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Episodic and Continuous Breathlessness: A New Categorization of Breathlessness
Vol. 45 No. 6 June 2013
Journal of Pain and Symptom Management 1019
Original Article
Episodic and Continuous Breathlessness: A New Categorization of Breathlessness Steffen T. Simon, MD, MSc, Irene J. Higginson, BM, BS, BMedSci, PhD, FFPHM, FRCP, Hamid Benalia, BSc, MA, Marjolein Gysels, PhD, Fliss E.M. Murtagh, PhD, MRCGP, MSc, James Spicer, FRCP, PhD, MB, BS BA, and Claudia Bausewein, PhD, MD, MSc Department of Palliative Care, Policy and Rehabilitation (S.T.S., I.J.H., H.B., M.G., F.E.M.M., C.B.), King’s College London; Cicely Saunders Institute and Division of Cancer Studies (J.S.), King’s College London, Guy’s and St. Thomas’ NHS Foundation Trust, London, United Kingdom; Department of Palliative Medicine and Clinical Trials Unit (01KN1106) (S.T.S.), University Hospital Cologne, Cologne; and Institute of Palliative Care (S.T.S., C.B.), Oldenburg, Germany; and Interdisciplinary Centre for Palliative Medicine (C.B.), University Hospital Munich, Munich, Germany
Abstract Context. Unlike pain, where the concept of breakthrough and background pain has been widely characterized and defined, breathlessness as a symptom has not yet been fully explored and has been rarely categorized. Objectives. To explore patients’ experiences and descriptions of breathlessness to categorize breathlessness. Methods. Qualitative study using in-depth interviews with patients suffering from four life-limiting and advanced diseases (chronic heart failure, chronic obstructive pulmonary disease, lung cancer, and motor neuron disease). Interviews were tape-recorded, transcribed verbatim, and analyzed using Framework analysis. Results. A total of 51 participants were interviewed (mean SD age 68.2 11.6 years; 30 of 51 male; median Karnofsky 60%; mean SD breathlessness intensity 3.2 1.7 of 10). Episodic breathlessness and continuous breathlessness were the main categories, with subcategories of triggered and non-triggered episodic breathlessness and continuous breathlessness for short and long periods. Episodic breathlessness triggered by exertion, non-triggered episodic breathlessness, and continuous breathlessness for a long period (‘‘constant variable’’) were the most frequent and important categories with a high impact on daily living. Exertional breathlessness occurred in nearly all participants. Participants could differentiate episodic breathlessness (seconds, minutes, or hours) and continuous breathlessness (days, weeks, or months) by time. Episodic breathlessness occurred in isolation or in conjunction with continuous breathlessness.
Address correspondence to: Steffen T. Simon, MD, MSc, Department of Palliative Medicine, University Hospital Cologne, Kerpener Str. 62, 50924 Cologne, Germany. E-mail: [email protected] Ó 2013 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.
Accepted for publication: June 14, 2012.
0885-3924/$ - see front matter http://dx.doi.org/10.1016/j.jpainsymman.2012.06.008
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Conclusion. Participants categorize their breathlessness by time and triggers. The categorization needs further verification, similar to that already established in pain, and can be used as a new evidence-based categorization to advance our understanding of this under-researched, yet high impact, symptom to optimize management. J Pain Symptom Manage 2013;45:1019e1029. Ó 2013 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved. Key Words Breathlessness, dyspnea, episodic, continuous, categorization
Introduction Breathlessness is defined by the American Thoracic Society as ‘‘a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity.’’1 Breathlessness is a common and distressing symptom in patients with advanced diseases. It is highly prevalent, for example, in patients with chronic obstructive pulmonary disease (COPD) (90e95%) or lung cancer (78%), two of the most common diseases worldwide.2,3 A rich body of qualitative studies describes the burdensome impact of breathlessness on daily life.4 However, the management of breathlessness is complex and still insufficient.5 In addition, breathlessness is a relevant cost factor for health care systems; it is one of the leading symptoms resulting in emergency admissions.6 The presentation of breathlessness varies regarding intensity and the course of breathlessness.1 Patients describe episodes of breathlessness as an incident or acute event with sudden onset that is unpleasant and often causes panic.7 These episodes are often triggered by exertion, for example, climbing stairs, walking, or even talking.8 In contrast, breathlessness can be present all the time, even at rest, as a continuous burden to the patient.9 Reddy et al.10 used these dichotomous categories of episodic (or breakthrough) breathlessness and continuous (or constant) breathlessness to describe the length and frequency of episodes of breathlessness and the intensity level of episodic and continuous breathlessness. In this descriptive survey of 70 cancer patients, a screening question (‘‘How often are you short of breath?’’) was used and answers were grouped: ‘‘all the time’’ and ‘‘most of the time’’ as continuous breathlessness and ‘‘some of the time’’ and ‘‘a little of the time’’ as episodic breathlessness.10 The use of dichotomous categories is supported by other
studies.1,8 However, it is still unclear how the two main categories can be clearly differentiated from each other based on patients’ experiences and which subcategories exist. To our knowledge, no categorization of breathlessness exists that describes how categories are related to each other. The lack of standardization and well-defined order of categories hinders further developments in clinical care and research of breathlessness. Clinical assessment needs clearly defined and well-described categories and criteria to get an appropriate diagnosis to inform management. In research, the lack of categorization makes the comparison of studies difficult or even impossible and hampers systematic reviews and trials. Therefore, the aim of this study was to explore patients’ experiences and descriptions of breathlessness to categorize breathlessness.
Methods Study Design This was a qualitative study with in-depth, face-to-face interviews.
Setting, Participants, and Recruitment Participant recruitment took place in five outpatient clinics of two university hospitals in south London over six months in 2010. Patients were eligible if suffering from breathlessness as a result of one of the following diseases: COPD (Stages III and IV of the Global Initiative for Obstructive Lung Disease classification), chronic heart failure (CHF) (Stages II to IV of the New York Heart Association classification), lung cancer (LC) (primary and secondary LC, all stages), and motor neuron disease (MND) (all stages).11,12 Participants could be on any treatment for the underlying disease or for breathlessness, including chemotherapy or radiotherapy. Patients were
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excluded if unable to give informed consent, were too ill to be interviewed, or had cognitive impairment (clinical judgment by the principal investigator). Sampling continued until saturation when no new information was gained. The consultant in the outpatient clinic initiated the first contact with potential eligible participants during the recruitment period. The researchers checked inclusion and exclusion criteria and gave detailed information about the study to the patients. Informed consent was obtained before the interview was conducted.
Data Collection A purposive sample was selected to acquire indepth information about experiences and characteristics of breathlessness from patients in the above-described disease groups. We used semistructured, in-depth, face-to-face interviews with an exploratory approach. Interviews were conducted independently by two trained interviewers (S. T. S. and H. B.) at participants’ homes (except when the participant wished to conduct the interview elsewhere). We encouraged participants to think aloud and talk about any topic they felt to be important in the area of breathlessness. A topic guide was used to ensure that all relevant predefined topics were addressed, including general experience with breathlessness; experiences, characteristics, and triggers of episodic breathlessness; impact on daily living; management strategies; and health care use. Every interview started by asking about the general experience of breathlessness. In this study, episodic breathlessness was preliminarily defined as ‘‘breathlessness occurring intermittently in patients with and without underlying continuous breathlessness’’ according to Reddy et al.10 Demographic and clinical data were obtained before the interview started (Table 1). These included severity of breathlessness measured on the modified Borg Scale, a numeric scale from 0 to 10 combined with verbal descriptors of severity from ‘‘not at all’’ to ‘‘maximum,’’13 and a measure of comorbidity, the Charlson Comorbidity Index, which includes a range of 22 conditions.14 Debriefing was provided after each interview to discover potential harm or burdensome emotions, thoughts, and memories and offer support if needed (having an emergency plan in place). All interviews were tape-recorded and transcribed verbatim.
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Table 1 Demographic and Clinical Characteristics of Participants (N ¼ 51) Characteristics Age, years, mean (SD), range Gender, male Disease group (stage) COPD LC (entity) CHF MND Ethnicity White British White others Black African Black Caribbean Indian Living situation, alone Karnofsky Index, median (range) CCI Missing No risk Mild risk Moderate risk Severe risk Smoking Still smoking Smoked but stopped Never smoked Oxygen supply Severity of breathlessness in general, mod. Borg, mean (SD) Average 24 hours Worst Now Rest On exertion
n (%)a 68.2 (11.6), 39e92 30 (59) 14 (7 GOLD-III, 7 GOLD-IV) 13 (7 primary LC, 4 mesothelioma, 2 secondary LC (breast)) 15 (2 NYHA-II, 10 NYHA-III, 3 NYHA-IV) 9 32 7 3 5 4 19 60
(63) (14) (6) (10) (8) (37) (30e90)
4 7 18 11 11
(8) (14) (35) (22) (22)
3 31 17 14
(6) (61) (33) (28)
3.2 5.4 1.7 1.2 5.4
(1.7) (2.4) (1.6) (1.2) (2.1)
COPD ¼ chronic obstructive pulmonary disease; GOLD ¼ Global initiative for chronic Obstructive Lung Disease; LC ¼ lung cancer; CHF ¼ chronic heart failure; NYHA ¼ New York Heart Association; MND ¼ motor neuron disease; CCI ¼ Charlson Comorbidity Index; mod. Borg ¼ modified Borg Scale. a Unless otherwise noted.
In addition, field notes of observational and interactional data were recorded in participantrelated memos after each interview.
Data Analysis The analysis was conducted using the Framework analysis method. This is a matrix-based method using a thematic framework to classify and organize data by key themes, concepts, and categories.15 First, all interviews and memos were read twice by the principal investigator (S. T. S.) to become familiar with the content. The following analytic hierarchy guided the
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analysis: data management (identifying initial themes and coding), descriptive accounts (sorting, summarizing, and identifying dimensions and categories), and explanatory accounts (detecting patterns, identifying clusters, and developing explanations and a theory). Descriptive (Table 2) and explanatory accounts (Figs. 1e3) are presented in this study. We used the dichotomous categories ‘‘episodic and continuous breathlessness’’ as a starting point and explored participants’ understanding and the experiences with these topics. The computer program NVivo (version 8) (QSR International (UK) Limited, Southport, U.K.) was used for data management. The stages of descriptive and explanatory accounts were facilitated by creating thematic charts with all participants in rows and categories in columns, in particular for thematic-related (inter-participant) and participant-related (interthematic) analysis. The analysis was conducted by the principal investigator. At the beginning, five interviews were coded by two additional reviewers who were part of the study group (C. B. and F. M.) to address rigor and trustworthiness. Differences were discussed and consensus achieved. At every stage of the analysis (indexing, charting, descriptive analysis, interpretation and explanation, and final results), findings were discussed by the study group and results of these discussions incorporated. In addition to the qualitative analysis, the
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proportion of patients who experienced the described type of breathlessness in each category was calculated.15
Ethics Ethical approval was obtained by The Joint University College London/University College London Hospitals Committees on the Ethics of Human Research Alpha (09/H0715/81). The study was registered by the National Institute for Health Research Clinical Research Network Portfolio (NIHR CRN Study ID 7859) and at ClinicalTrials.gov (NCT01138358).
Results Participants’ Characteristics Fifty-one participants were included in this study with a mean age of 68 years and mixed ethnic backgrounds but predominantly white; 30 of the 51 were male, and 19 of 51 lived alone (Table 1). We interviewed 14 participants with COPD, 13 with primary or secondary LC, 15 with CHF, and nine with MND. Patients suffered mainly from advanced stages of their disease, and 22 of 51 were determined to be moderately or severely ill based on their Charlson Comorbidity Index scores. The median Karnofsky performance status was 60% (can take care of most personal requirements but needs some help),
Table 2 List of Triggers for Breathlessness A1dExertion
Walking (38) Climbing stairs (34) Talking (28) Slightly exertion (21) Stand up (11) Carrying things (10) Dressing/clothing (9) Bending/leaning forward (9) Housework (9), gardening Doing things in a rush (7) Lifting things (6) Eating/drinking (3) Showering (2) Stretching arms/lifting arms Standing in line Rolling over in bed at night Laughing, screaming Sex On the bicycle (exercise) machine
A2dEmotion
Panic (16) Anger (11) Excitement, upset (10) Anxiety, fear (9) Stress (5) Impatience Argument Claustrophobia Annoyed, frustrated Worry about something Nervous Happy
A3dEnvironment Cold temperature (air, weather) (15) Hot temperature (14) Lie down flat (14) Tiredness (9) Perfumes, chemicals (9) Dry air (5) Wind (5) Dust, humid air (5) Mucus (4) Pollen Stir fry (hot fat) Vinegar Powder Anesthetic spray
C1dReasons for Short Period CB
Chest infection (8) Acute exacerbation (COPD) (4) Acute decompensation (CHF) (3) Chemotherapy (3) Anemia Pleural effusion
CB ¼ continuous breathlessness; COPD ¼ chronic obstructive pulmonary disease; CHF ¼ chronic heart failure. In brackets: number of participants who report this trigger; no bracket ¼ report of one participant only.
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Fig. 1. Relationship between EB and CB. The uneven surface of the blue box should illustrate the variable intensity of continuous breathlessness (please refer the online version for colors). EB ¼ episodic breathlessness; CB ¼ continuous breathlessness.
one-third of the participants never smoked, and 14 of 51 needed oxygen supply. The mean severity of breathlessness over the last 24 hours was 3.2 (SD 1.7) on the modified Borg Scale (0e10) and at worst 5.4 (SD 2.4), with the highest numbers in patients with LC and the lowest in MND. The interviews mostly took place in participants’ homes (45 of 51) and lasted for a median of 55 minutes (range 17e89 minutes).
Differentiation Between Episodic Breathlessness and Continuous Breathlessness Participants differentiated episodic breathlessness and continuous breathlessness by time: episodic breathlessness was characterized
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as being breathless for seconds, minutes, or hours (less than 24 hours) and continuous breathlessness was described by breathlessness longer than 24 hours (days, weeks, months, or years). Terms for episodic breathlessness were the following: attack, acute breathlessness, crisis, episode, gradual, incident, increase, period, spasmodic, and spontaneous. For continuous breathlessness, participants used the following terminology: breathlessness, breathlessness at rest, breathlessness all the time, constant, constant variable, continuous, fluctuating, and bad days. Episodic breathlessness: The episode comes and goes as, as it will. (Male, 79 years, COPD) Continuous breathlessness: You’re always a bit breathless. (Male, 70 years, COPD) Participants described a clear relationship between episodic breathlessness and continuous breathlessness using two options: 1) episodic breathlessness only, without continuous breathlessness or 2) continuous breathlessness plus episodic breathlessness (including all subcategories). Participants did not describe continuous breathlessness without episodic breathlessness; 11 of 51 (22%) participants reported episodic breathlessness only, whereas
Fig. 2. Categorization of breathlessness by time and triggers based on patients’ experiences. EB ¼ episodic breathlessness; CB ¼ continuous breathlessness.
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Fig. 3. Main categories of breathlessness.
40 of 51 (78%) participants experienced both categories (Fig. 1).
Two Types of Episodic Breathlessness: Triggered and Non-Triggered Participants described episodic breathlessness as being breathless for a certain time (framed by onset and recovery). When participants were asked to report their experience of episodic breathlessness, they described two different subgroups based on the existence of a trigger as a differentiator. Episodic breathlessness could either be caused by a distinct trigger or have occurred ‘‘out of the blue’’ without any identifiable trigger. Participants reported different triggers causing breathlessness. The most common subcategory of triggered episodic breathlessness was exertional breathlessness. Different levels of exertion were described: some participants became breathless by the slightest exertion, for example, walking a few steps on flat ground or just by talking, whereas others experienced breathlessness only after climbing some stairs or lifting heavy loads. However, most experienced an aggravation or worsening of their underlying breathlessness by becoming much more breathless compared with a healthy person. Overall, the severity and length of episodic breathlessness was related to the exertional level, with slight exertion causing mild and short episodes of breathlessness and high levels of exertion causing severe and longer episodes of breathlessness. Participants with exertional breathlessness described long walks, climbing stairs, and talking as common triggers but emphasized that carrying or lifting something (not necessarily heavy loads), rushing, or bending over were specific triggers that caused breathlessness very quickly (Table 2, A1). Now my breathlessness starts just a bit when I am talking or, er, when I am going up and down. (Female, 84 years, lung cancer)
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In addition, episodic breathlessness could be triggered by emotions and emotions could worsen continuous breathlessness or exertional breathlessness, which led to emergency calls when episodes of breathlessness were getting out of control. Panic, anger, and excitement were the most common emotional triggers of episodic breathlessness (Table 2, A2). When you are getting angry about something that seems to trigger it off. (Female, 69 years, COPD) Panic makes it worse. (Male, 89 years, CHF) Other triggers (e.g., environmental factors) potentially causing episodic breathlessness were extreme temperature (both cold and hot), chemicals (e.g., perfume), certain positions (e.g., lying down), or dust (Table 2, A3). I can’t stand people with deodorants on and that affects me quite badly. (Male, 69 years, COPD) Forty-nine percent of participants reported episodic breathlessness that occurred without warning and was unpredictable (coming ‘‘out of the blue’’). No trigger could be identified, and episodes could not be related to a certain situation or time. It was often characterized by quick onset, short duration, and severe intensity. This non-triggered episodic breathlessness was more common in patients with COPD and less common in MND but occurred in all disease groups. Sitting, watching television and then all of a sudden it comes on like that with no reason at all. (Female, 74 years, LC) Participants described episodic breathlessness as being breathless for a certain time (framed by onset and recovery). In contrast, continuous breathlessness was experienced as breathlessness all the time without breathlessfree intervals.
Two Manifestations of Continuous Breathlessness: Short Period and Long Period Some participants experienced continuous breathlessness as breathlessness all the time and even at rest. Although they tried to suppress or forget the continuous impairment of their breathing, a certain level of continuous breathlessness was always present. However,
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participants described the intensity level not as a continuum but as variable and fluctuating. Even participants with very severe continuous breathlessness (e.g., 8/10 or 9/10) judged the continuous breathlessness intensity at rest quite low but sometimes the slightest exertion triggered a severe level of continuous breathlessness. In addition, participants described bad days when they were severely breathless alternating with better days when continuous breathlessness was not such a burden. It’s a variable constant. (Male, 65 years, lung cancer) Sometimes you have better days than others. (Male, 72 years, CHF) Two subcategories of continuous breathlessness could be differentiated by time. First, some participants experienced continuous breathlessness only over a short period (days or weeks), for example, when they suffered from a chest infection or exacerbation of COPD (Table 2, C1). Basically, these participants only had episodes of breathlessness (e.g., exertional breathlessness), but for a certain time during a chest infection they were breathless all day long and reported this as continuous breathlessness. Second, some participants reported being breathless all the time for a long period and were familiar with this situation for months or even years as a chronic condition (e.g., patients with COPD). Exacerbation of COPD during winter time: When I really am bad I just can’t talk, I just can’t breathe, I just can’t do anything. (Male, 79 years, COPD) Chronic condition: It is there all the time, it never goes away. [.] it’s fighting for your life all the time. (Male, 76 years, COPD)
Categorization of Breathlessness by Time and Trigger Participants’ experiences and descriptions of different categories and subcategories of breathlessness allow a categorization of breathlessness (Fig. 2). First, episodic breathlessness and continuous breathlessness can be differentiated by time: episodic breathlessness can be defined by the length of the episode in seconds, minutes, or hours, whereas continuous breathlessness is characterized by breathlessness over a long
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period of time, for example, days, weeks, months, or even years. Second, two subcategories of episodic breathlessness can be identified in relation to triggers. Episodic breathlessness can be triggered by a known cause (Adtriggered episodic breathlessness), for example, exertion, emotion, or others (A1e3), or episodic breathlessness can occur ‘‘out of the blue’’ without a known trigger (Bdnon-triggered episodic breathlessness). In addition, two subcategories of continuous breathlessness are differentiated by time: breathlessness over days or weeks, for example, caused by pleural effusion or chest infection (C1dshort period of continuous breathlessness) and breathlessness over months or years without an expected end (C2dlong period of continuous breathlessness) (Fig. 2). The term chronic breathlessness was used for the overall duration of patients’ experience of breathlessness (episodic and/or continuous breathlessness) over a period of months or longer. The median duration of participants’ experiences of breathlessness (episodic and/ or continuous breathlessness) was 24 months (range 1e420; n ¼ 48). The categories or subcategories of breathlessness that were most prevalent were: exertional breathlessness (A1), non-triggered episodic breathlessness (B), and continuous breathlessness over a long period best described as a ‘‘constant variable’’ (C2) (Fig. 3). The prevalence of all categories is listed in Table 3. All participants in our study experienced triggered episodic breathlessness (A1e3); 25 of 51 (50%) participants experienced non-triggered episodic breathlessness (B), with unpredictable breathlessness; and 40 of 51 (78%) participants described at least one subcategory of continuous breathlessness (C1 and/or C2). The prevalence varied between the four different disease groups but was more consistent for exertional breathlessness (A1) and continuous breathlessness over a long period (C2). Eight participants described all subcategories, and two participants referred to exertional breathlessness (A1) only.
Discussion This is the first study to categorize breathlessness based on patients’ experiences by time
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Table 3 Prevalence of Six Different Classification Groups of Breathlessness by Underlying Disease Disease Group
n
CHF, n (%) LC, n (%) COPD, n (%) MND, n (%) Total, n (%)
15 13 14 9 51
A1 (EB by Exertion) 15 13 14 8a 50
(100) (100) (100) (89) (98)
A2 (EB by Emotion) 10 8 11 2 31
(67) (62) (79) (22) (61)
A3 (EB by Environment) 5 8 11 8 32
B (Non-Triggered EB)
(33) (62) (79) (89) (63)
9 5 10 1 25
(60) (38) (71) (11) (49)
C1 (CB Short Period) 5 4 11 2 22
(33) (31) (79) (22) (43)
C2 (CB Long Period) 10 8 12 6 36
(67) (62) (86) (67) (71)
EB ¼ episodic breathlessness; CB ¼ continuous breathlessness; CHF ¼ chronic heart failure; LC ¼ lung cancer; COPD ¼ chronic obstructive pulmonary disease; MND ¼ motor neuron disease. a One patient with MND was quadriplegic, not able to exert and did not experience exertional breathlessness.
and triggers in patients with advanced disease, providing a new categorization for a better understanding of breathlessness. The main categories, episodic breathlessness and continuous breathlessness, can be differentiated by time using 24 hours as a preliminary cutoff and can be subcategorized into triggered and nontriggered episodic breathlessness and continuous breathlessness for short and long periods. These categories are clinically relevant and helpful for the assessment of breathless patients. In addition, the categorization of breathlessness will help to define patient groups in breathlessness research to evaluate and develop effective treatments and to compare studies accurately. The presented categorization of breathlessness, including subcategories and cutoffs, needs further verification and adaptation in clinical practice and surveys.
Time Episodic breathlessness and continuous breathlessness are discriminated by time using 24 hours as a cutoff, as participants characterized the duration of episodes of breathlessness only in seconds, minutes, and hours but never in days, weeks, or months. The only studies that evaluated the duration of episodes of breathlessness consistently described episodic breathlessness in minutes and hours (most frequently between 5 and 15 minutes).8,10,16 Our study supports these findings and suggests a cutoff (24 hours). Participants characterized episodic breathlessness as breathlessness with a beginning and an end. This also applies to longer periods of breathlessness over days or weeks, for example, when having a chest infection with severe breathlessness. As participants described the sensation of breathlessness during this period as continuous or all the time, we categorized
this as continuous breathlessness (short period of continuous breathlessness, C1 in Fig. 2). This subcategory also could be categorized in two different ways. First, it could be placed as a subcategory of episodic breathlessness because episodic breathlessness was preliminarily defined as ‘‘breathlessness occurring intermittently’’ with an onset and end, which also applies for C1. Second, it could be grouped as a third main category between episodic breathlessness and continuous breathlessness: episodic breathlessness (less than 24 hours), periodic breathlessness (days or weeks), and continuous breathlessness (months or years). We categorized C1 as a subcategory of continuous breathlessness because we used the dichotomous categories of episodic breathlessness and continuous breathlessness preliminarily and participants described C1 within this dichotomy as continuous breathlessness. However, we did not explore whether they would have preferred a third main category instead of the dichotomous categorization. To our knowledge, no study has used three main categories in the categorization of breathlessness. This needs further exploration in a future study.
Triggers Exertion was the most frequent trigger for episodes of breathlessness and described by all patients in this study (except one quadriplegic patient who was not able to exert). In participants with additional continuous breathlessness, sometimes the slightest exertion aggravated baseline levels of continuous breathlessness up to severe intensity resulting in limited mobility and high impact on daily life. The relevance of exertional breathlessness is frequently described.1 Episodic breathlessness by exertion is the main cause of breathlessness in patients with COPD.17,18 In
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reducing activity, patients try to prevent and relieve breathlessness, but this leads to inactivity and deconditioning, with a vicious cycle of worsening quality of life and social loss. Similar experiences were reported for patients with cancer, and exertional triggers have been identified as most common.8 There is increasing evidence and better understanding about the neurophysiological mechanisms of episodic breathlessness by exertion involving ventilator load, respiratory muscle capacity, neural respiratory drive, and neuromechanical dissociation.19 However, exertion not only triggers episodic breathlessness but also can increase exercise capacity when used appropriately, for example, during pulmonary rehabilitation for COPD patients.20 Finally, different levels of exertion or exercise capacity are used as measurement criteria in tools to evaluate breathlessness severity, for example, the Medical Research Council Breathlessness Scale or the Oxygen Cost Diagram.21 Therefore, the category episodic breathlessness by exertion or, in other words, the impairment of daily activity is used as an indicator for the severity of breathlessness in general. Besides exertion, a variety of triggers is known and has been described before, such as emotions (e.g., panic and anger) and environmental factors (e.g., cold wind and perfume). In our study, exertion and emotion were the most important and most prevalent triggers and could occur simultaneously and exacerbate each other, for example, being upset and rushing to the telephone. These situations can lead to severe episodes of breathlessness with the possibility of losing control of the situation and needing to call an ambulance. Our findings are supported by trigger lists of other studies and add some new factors.8,9,22,23
Non-Triggered Episodic Breathlessness Non-triggered episodic breathlessness has rarely been reported before. A recent systematic review on episodic breathlessness identified only four qualitative studies that mentioned this category, with limited information.7,16,17,24,25 In a sample of 18 COPD patients, some patients reported the sudden onset and rapid disappearance of episodic breathlessness without knowing the trigger (e.g., no exertion).24 In a mixed sample of
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COPD and cancer patients, only patients with cancer described unpredictable and inexplicable episodic breathlessness.7 In our study, nearly half of the patients reported this unpredictable form of episodic breathlessness, which occurred most often in patients with COPD and rarely in MND patients. It could be argued that participants might not remember the trigger or do not want to report the trigger (e.g., anxiety or panic).7 Although this might be the case in a few patients, it seems to be unlikely for all because of the consistency in reporting by half of the participants in this sample. Additionally, anxiety, panic, and other sensitive issues were frequent topics during the in-depth interviews with no correlation between this category of episodic breathlessness and patients who did not want to talk about sensitive issues.
Continuous Breathlessness as a ‘‘Constant Variable’’ Continuous breathlessness is a continuum in terms of ‘‘present all the time’’ but very variable and fluctuating regarding the intensity level. All triggers of episodic breathlessness (A1e3) and especially exertion can aggravate continuous breathlessness but so can changes in the daily condition. In a qualitative study on COPD patients, the ‘‘invisibility’’ of breathlessness was described when the patient seemed to be all right at rest (without breathlessness) but severely disabled by breathlessness during slightest exertion (walking to the bathroom).24 Mainly, participants with COPD reported this fluctuation in our study, but it occurred in all disease groups. The variability of continuous breathlessness is one reason why the management of breathlessness is challenging in finding the right balance in pharmacological treatment between overdosing and underdosing. Clinical experience and trial evidence suggest lower doses of morphine in the management of breathlessness in contrast to pain. A recent pharmacovigilance study with a mixed disease group of patients (predominantly COPD) showed that 10 mg sustained-released morphine once daily was effective for most patients.5 In addition and because of the variability of continuous breathlessness, measurement of breathlessness in clinical practice and in trials should cover breathlessness ‘‘over the past 24 hours’’ and not only ‘‘right now.’’26
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Strengths and Limitations One of the strengths of this study is that the provided categorization of breathlessness by time and triggers is based on patient experience and not just clinical observation. This advances our understanding of this complex symptom to inform appropriate and effective management. Second, patients from different disease groups were included in the study. This allows the proposed classification to be applicable in diseases with a high prevalence of breathlessness and not only to one disease. There also are some limitations. Although this was a qualitative study, we do present some numbers and proportions to give an indication of the distribution of the breathlessness categories in the different disease groups; however, the small numbers do not allow any statistical analysis. Therefore, the prevalence of different categories needs further verification in a larger survey with sufficient statistical power and higher numbers of participants. Episodic breathlessness in this study might have been overestimated and categories biased toward episodic breathlessness, as the main focus of the interviews was to explore experiences and characteristics of episodic breathlessness. However, participants were not only asked about episodic breathlessness but about their general experience with breathlessness (including continuous breathlessness) and how episodic breathlessness differed from continuous breathlessness.
Implications for Clinical Practice and Research First, breathless patients experience breathlessness in different ways and with different characteristics. We need to label these different patient experiences and develop a shared terminology among both clinicians and researchers to speak the same language. Therefore, a consensus about categories, definitions, and terminology is needed. Second, the categorization should help to describe the interrelation between categories as well as differentiators and cutoffs. This is most relevant for finding the most effective and most appropriate treatment because different categories might need different management strategies. Third, the categorization should inform the clinical assessment of breathless patients to evaluate from
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which kind of breathlessness the patient is suffering. The three main categories (Fig. 3) can lead clinical assessment. In addition, symptomatic management of breathlessness (episodic and continuous breathlessness) should always start with the evaluation of reversible triggers and optimization of the treatment of the underlying disease. The list of triggers (A1e3 and C1) might be helpful as a checklist. Fourth, the categorization should inform research to develop effective management strategies and for a better comparison of studies in the area of breathlessness using the same terminology and categories.
Conclusion We provide a new evidence-based categorization of breathlessness by time and triggers based on patient reports. The categorization needs further verification in larger surveys and a consensus about definitions and terminology similar to those already established in pain. Consistent, evidence-based, and clear definitions are a crucial foundation for research into effective interventions to optimize management.
Disclosures and Acknowledgments This study was supported by a research grant from the Dr. Werner Jachst€adt Foundation, Wuppertal, Germany and by Cicely Saunders International, London, U.K., without any influence on study design, analysis, interpretation, or presentation. The authors declare no conflicts of interest. The authors extend special thanks to all the patients who gave deep insights into their experiences of breathlessness. They thank Caroline Jolley, John Moxham, Julia DeCoursey, Andrew Dougherty, Nigel Leigh, and Emma Willey for their supportive recruitment of participants for this study and Cathy Shipman, Jonathan Koffman, Lucy Selman, Cassie Goddard, and Christina Ramsenthaler for their support during the analysis.
References 1. American Thoracic Society. Dyspnea. Mechanisms, assessment, and management: a consensus
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statement. Am J Respir Crit Care Med 1999;159: 321e340.
breathlessness in asthma. Am Rev Respir Dis 1982; 126:825e828.
2. Solano JP, Gomes B, Higginson IJ. A comparison of symptom prevalence in far advanced cancer, AIDS, heart disease, chronic obstructive pulmonary disease and renal disease. J Pain Symptom Manage 2006;31:58e69.
14. Charlson M, Szatrowski TP, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol 1994;47:1245e1251.
3. Edmonds P, Karlsen S, Khan S, AddingtonHall J. A comparison of the palliative care needs of patients dying from chronic respiratory diseases and lung cancer. Palliat Med 2001;15:287e295. 4. Gysels M, Bausewein C, Higginson IJ. Experiences of breathlessness: a systematic review of the qualitative literature. Palliat Support Care 2007;5: 281e302. 5. Currow DC, McDonald C, Oaten S, et al. Oncedaily opioids for chronic dyspnea: a dose increment and pharmacovigilance study. J Pain Symptom Manage 2011;42:388e399. 6. Barbera L, Taylor C, Dudgeon D. Why do patients with cancer visit the emergency department near the end of life? CMAJ 2010;182:563e568. 7. Booth S, Silvester S, Todd C. Breathlessness in cancer and chronic obstructive pulmonary disease: using a qualitative approach to describe the experience of patients and carers. Palliat Support Care 2003;1:337e344. 8. O’Driscoll M, Corner J, Bailey C. The experience of breathlessness in lung cancer. Eur J Cancer Care (Engl) 1999;8:37e43. 9. Henoch I, Bergman B, Gustafsson M, GastonJohansson F, Danielson E. Dyspnea experience in patients with lung cancer in palliative care. Eur J Oncol Nurs 2008;12:86e96. 10. Reddy SK, Parsons HA, Elsayem A, Palmer JL, Bruera E. Characteristics and correlates of dyspnea in patients with advanced cancer. J Palliat Med 2009;12:29e36. 11. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global strategy for the diagnosis, management and prevention of COPD. 2010. Available from http://www.goldcopd.org. Accessed June 2, 2012. 12. Heart Failure Society of America. NYHA classification. 2002. Available from http://www.abouthf. org/questions_stages.htm. Accessed June 2, 2012. 13. Burdon JG, Juniper EF, Killian KJ, Hargreave FE, Campbell EJ. The perception of
15. Ritchie J, Lewis J. Qualitative research practice. London, UK: Sage Publications, 2004. 16. Lai YL, Chan CW, Lopez V. Perceptions of dyspnea and helpful interventions during the advanced stage of lung cancer: Chinese patients’ perspectives. Cancer Nurs 2007;30:E1eE8. 17. Barnett M. Chronic obstructive pulmonary disease: a phenomenological study of patients’ experiences. J Clin Nurs 2005;14:805e812. 18. Gysels MH, Higginson IJ. Self-management for breathlessness in COPD: the role of pulmonary rehabilitation. Chron Respir Dis 2009;6:133e140. 19. Jolley CJ, Moxham J. A physiological model of patient-reported breathlessness during daily activities in COPD. Eur Respir Rev 2009;18:66e79. 20. O’Donnell DE, McGuire M, Samis L, Webb KA. The impact of exercise reconditioning on breathlessness in severe chronic airflow limitation. Am J Respir Crit Care Med 1995;152:2005e2013. 21. Bausewein C, Farquhar M, Booth S, Gysels M, Higginson IJ. Measurement of breathlessness in advanced disease: a systematic review. Respir Med 2007;101:399e410. 22. Janson-Bjerklie S, Carrieri VK, Hudes M. The sensations of pulmonary dyspnea. Nurs Res 1986; 35:154e159. 23. Henoch I, Bergman B, Danielson E. Dyspnea experience and management strategies in patients with lung cancer. Psychooncology 2008;17:709e715. 24. Gysels M, Higginson IJ. Access to services for patients with chronic obstructive pulmonary disease: the invisibility of breathlessness. J Pain Symptom Manage 2008;36:451e460. 25. Simon ST, Bausewein C, Schildmann E, et al. Episodic breathlessness (EB) in patients with advanced disease: a systematic review. J Pain Symptom Manage 2012. [Epub ahead of print]. 26. Dorman S, Jolley C, Abernethy A, et al. Researching breathlessness in palliative care: consensus statement of the National Cancer Research Institute Palliative Care Breathlessness Subgroup. Palliat Med 2009;23:213e227.
Journal of Pain and Symptom Management 1019
Original Article
Episodic and Continuous Breathlessness: A New Categorization of Breathlessness Steffen T. Simon, MD, MSc, Irene J. Higginson, BM, BS, BMedSci, PhD, FFPHM, FRCP, Hamid Benalia, BSc, MA, Marjolein Gysels, PhD, Fliss E.M. Murtagh, PhD, MRCGP, MSc, James Spicer, FRCP, PhD, MB, BS BA, and Claudia Bausewein, PhD, MD, MSc Department of Palliative Care, Policy and Rehabilitation (S.T.S., I.J.H., H.B., M.G., F.E.M.M., C.B.), King’s College London; Cicely Saunders Institute and Division of Cancer Studies (J.S.), King’s College London, Guy’s and St. Thomas’ NHS Foundation Trust, London, United Kingdom; Department of Palliative Medicine and Clinical Trials Unit (01KN1106) (S.T.S.), University Hospital Cologne, Cologne; and Institute of Palliative Care (S.T.S., C.B.), Oldenburg, Germany; and Interdisciplinary Centre for Palliative Medicine (C.B.), University Hospital Munich, Munich, Germany
Abstract Context. Unlike pain, where the concept of breakthrough and background pain has been widely characterized and defined, breathlessness as a symptom has not yet been fully explored and has been rarely categorized. Objectives. To explore patients’ experiences and descriptions of breathlessness to categorize breathlessness. Methods. Qualitative study using in-depth interviews with patients suffering from four life-limiting and advanced diseases (chronic heart failure, chronic obstructive pulmonary disease, lung cancer, and motor neuron disease). Interviews were tape-recorded, transcribed verbatim, and analyzed using Framework analysis. Results. A total of 51 participants were interviewed (mean SD age 68.2 11.6 years; 30 of 51 male; median Karnofsky 60%; mean SD breathlessness intensity 3.2 1.7 of 10). Episodic breathlessness and continuous breathlessness were the main categories, with subcategories of triggered and non-triggered episodic breathlessness and continuous breathlessness for short and long periods. Episodic breathlessness triggered by exertion, non-triggered episodic breathlessness, and continuous breathlessness for a long period (‘‘constant variable’’) were the most frequent and important categories with a high impact on daily living. Exertional breathlessness occurred in nearly all participants. Participants could differentiate episodic breathlessness (seconds, minutes, or hours) and continuous breathlessness (days, weeks, or months) by time. Episodic breathlessness occurred in isolation or in conjunction with continuous breathlessness.
Address correspondence to: Steffen T. Simon, MD, MSc, Department of Palliative Medicine, University Hospital Cologne, Kerpener Str. 62, 50924 Cologne, Germany. E-mail: [email protected] Ó 2013 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.
Accepted for publication: June 14, 2012.
0885-3924/$ - see front matter http://dx.doi.org/10.1016/j.jpainsymman.2012.06.008
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Conclusion. Participants categorize their breathlessness by time and triggers. The categorization needs further verification, similar to that already established in pain, and can be used as a new evidence-based categorization to advance our understanding of this under-researched, yet high impact, symptom to optimize management. J Pain Symptom Manage 2013;45:1019e1029. Ó 2013 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved. Key Words Breathlessness, dyspnea, episodic, continuous, categorization
Introduction Breathlessness is defined by the American Thoracic Society as ‘‘a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity.’’1 Breathlessness is a common and distressing symptom in patients with advanced diseases. It is highly prevalent, for example, in patients with chronic obstructive pulmonary disease (COPD) (90e95%) or lung cancer (78%), two of the most common diseases worldwide.2,3 A rich body of qualitative studies describes the burdensome impact of breathlessness on daily life.4 However, the management of breathlessness is complex and still insufficient.5 In addition, breathlessness is a relevant cost factor for health care systems; it is one of the leading symptoms resulting in emergency admissions.6 The presentation of breathlessness varies regarding intensity and the course of breathlessness.1 Patients describe episodes of breathlessness as an incident or acute event with sudden onset that is unpleasant and often causes panic.7 These episodes are often triggered by exertion, for example, climbing stairs, walking, or even talking.8 In contrast, breathlessness can be present all the time, even at rest, as a continuous burden to the patient.9 Reddy et al.10 used these dichotomous categories of episodic (or breakthrough) breathlessness and continuous (or constant) breathlessness to describe the length and frequency of episodes of breathlessness and the intensity level of episodic and continuous breathlessness. In this descriptive survey of 70 cancer patients, a screening question (‘‘How often are you short of breath?’’) was used and answers were grouped: ‘‘all the time’’ and ‘‘most of the time’’ as continuous breathlessness and ‘‘some of the time’’ and ‘‘a little of the time’’ as episodic breathlessness.10 The use of dichotomous categories is supported by other
studies.1,8 However, it is still unclear how the two main categories can be clearly differentiated from each other based on patients’ experiences and which subcategories exist. To our knowledge, no categorization of breathlessness exists that describes how categories are related to each other. The lack of standardization and well-defined order of categories hinders further developments in clinical care and research of breathlessness. Clinical assessment needs clearly defined and well-described categories and criteria to get an appropriate diagnosis to inform management. In research, the lack of categorization makes the comparison of studies difficult or even impossible and hampers systematic reviews and trials. Therefore, the aim of this study was to explore patients’ experiences and descriptions of breathlessness to categorize breathlessness.
Methods Study Design This was a qualitative study with in-depth, face-to-face interviews.
Setting, Participants, and Recruitment Participant recruitment took place in five outpatient clinics of two university hospitals in south London over six months in 2010. Patients were eligible if suffering from breathlessness as a result of one of the following diseases: COPD (Stages III and IV of the Global Initiative for Obstructive Lung Disease classification), chronic heart failure (CHF) (Stages II to IV of the New York Heart Association classification), lung cancer (LC) (primary and secondary LC, all stages), and motor neuron disease (MND) (all stages).11,12 Participants could be on any treatment for the underlying disease or for breathlessness, including chemotherapy or radiotherapy. Patients were
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excluded if unable to give informed consent, were too ill to be interviewed, or had cognitive impairment (clinical judgment by the principal investigator). Sampling continued until saturation when no new information was gained. The consultant in the outpatient clinic initiated the first contact with potential eligible participants during the recruitment period. The researchers checked inclusion and exclusion criteria and gave detailed information about the study to the patients. Informed consent was obtained before the interview was conducted.
Data Collection A purposive sample was selected to acquire indepth information about experiences and characteristics of breathlessness from patients in the above-described disease groups. We used semistructured, in-depth, face-to-face interviews with an exploratory approach. Interviews were conducted independently by two trained interviewers (S. T. S. and H. B.) at participants’ homes (except when the participant wished to conduct the interview elsewhere). We encouraged participants to think aloud and talk about any topic they felt to be important in the area of breathlessness. A topic guide was used to ensure that all relevant predefined topics were addressed, including general experience with breathlessness; experiences, characteristics, and triggers of episodic breathlessness; impact on daily living; management strategies; and health care use. Every interview started by asking about the general experience of breathlessness. In this study, episodic breathlessness was preliminarily defined as ‘‘breathlessness occurring intermittently in patients with and without underlying continuous breathlessness’’ according to Reddy et al.10 Demographic and clinical data were obtained before the interview started (Table 1). These included severity of breathlessness measured on the modified Borg Scale, a numeric scale from 0 to 10 combined with verbal descriptors of severity from ‘‘not at all’’ to ‘‘maximum,’’13 and a measure of comorbidity, the Charlson Comorbidity Index, which includes a range of 22 conditions.14 Debriefing was provided after each interview to discover potential harm or burdensome emotions, thoughts, and memories and offer support if needed (having an emergency plan in place). All interviews were tape-recorded and transcribed verbatim.
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Table 1 Demographic and Clinical Characteristics of Participants (N ¼ 51) Characteristics Age, years, mean (SD), range Gender, male Disease group (stage) COPD LC (entity) CHF MND Ethnicity White British White others Black African Black Caribbean Indian Living situation, alone Karnofsky Index, median (range) CCI Missing No risk Mild risk Moderate risk Severe risk Smoking Still smoking Smoked but stopped Never smoked Oxygen supply Severity of breathlessness in general, mod. Borg, mean (SD) Average 24 hours Worst Now Rest On exertion
n (%)a 68.2 (11.6), 39e92 30 (59) 14 (7 GOLD-III, 7 GOLD-IV) 13 (7 primary LC, 4 mesothelioma, 2 secondary LC (breast)) 15 (2 NYHA-II, 10 NYHA-III, 3 NYHA-IV) 9 32 7 3 5 4 19 60
(63) (14) (6) (10) (8) (37) (30e90)
4 7 18 11 11
(8) (14) (35) (22) (22)
3 31 17 14
(6) (61) (33) (28)
3.2 5.4 1.7 1.2 5.4
(1.7) (2.4) (1.6) (1.2) (2.1)
COPD ¼ chronic obstructive pulmonary disease; GOLD ¼ Global initiative for chronic Obstructive Lung Disease; LC ¼ lung cancer; CHF ¼ chronic heart failure; NYHA ¼ New York Heart Association; MND ¼ motor neuron disease; CCI ¼ Charlson Comorbidity Index; mod. Borg ¼ modified Borg Scale. a Unless otherwise noted.
In addition, field notes of observational and interactional data were recorded in participantrelated memos after each interview.
Data Analysis The analysis was conducted using the Framework analysis method. This is a matrix-based method using a thematic framework to classify and organize data by key themes, concepts, and categories.15 First, all interviews and memos were read twice by the principal investigator (S. T. S.) to become familiar with the content. The following analytic hierarchy guided the
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analysis: data management (identifying initial themes and coding), descriptive accounts (sorting, summarizing, and identifying dimensions and categories), and explanatory accounts (detecting patterns, identifying clusters, and developing explanations and a theory). Descriptive (Table 2) and explanatory accounts (Figs. 1e3) are presented in this study. We used the dichotomous categories ‘‘episodic and continuous breathlessness’’ as a starting point and explored participants’ understanding and the experiences with these topics. The computer program NVivo (version 8) (QSR International (UK) Limited, Southport, U.K.) was used for data management. The stages of descriptive and explanatory accounts were facilitated by creating thematic charts with all participants in rows and categories in columns, in particular for thematic-related (inter-participant) and participant-related (interthematic) analysis. The analysis was conducted by the principal investigator. At the beginning, five interviews were coded by two additional reviewers who were part of the study group (C. B. and F. M.) to address rigor and trustworthiness. Differences were discussed and consensus achieved. At every stage of the analysis (indexing, charting, descriptive analysis, interpretation and explanation, and final results), findings were discussed by the study group and results of these discussions incorporated. In addition to the qualitative analysis, the
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proportion of patients who experienced the described type of breathlessness in each category was calculated.15
Ethics Ethical approval was obtained by The Joint University College London/University College London Hospitals Committees on the Ethics of Human Research Alpha (09/H0715/81). The study was registered by the National Institute for Health Research Clinical Research Network Portfolio (NIHR CRN Study ID 7859) and at ClinicalTrials.gov (NCT01138358).
Results Participants’ Characteristics Fifty-one participants were included in this study with a mean age of 68 years and mixed ethnic backgrounds but predominantly white; 30 of the 51 were male, and 19 of 51 lived alone (Table 1). We interviewed 14 participants with COPD, 13 with primary or secondary LC, 15 with CHF, and nine with MND. Patients suffered mainly from advanced stages of their disease, and 22 of 51 were determined to be moderately or severely ill based on their Charlson Comorbidity Index scores. The median Karnofsky performance status was 60% (can take care of most personal requirements but needs some help),
Table 2 List of Triggers for Breathlessness A1dExertion
Walking (38) Climbing stairs (34) Talking (28) Slightly exertion (21) Stand up (11) Carrying things (10) Dressing/clothing (9) Bending/leaning forward (9) Housework (9), gardening Doing things in a rush (7) Lifting things (6) Eating/drinking (3) Showering (2) Stretching arms/lifting arms Standing in line Rolling over in bed at night Laughing, screaming Sex On the bicycle (exercise) machine
A2dEmotion
Panic (16) Anger (11) Excitement, upset (10) Anxiety, fear (9) Stress (5) Impatience Argument Claustrophobia Annoyed, frustrated Worry about something Nervous Happy
A3dEnvironment Cold temperature (air, weather) (15) Hot temperature (14) Lie down flat (14) Tiredness (9) Perfumes, chemicals (9) Dry air (5) Wind (5) Dust, humid air (5) Mucus (4) Pollen Stir fry (hot fat) Vinegar Powder Anesthetic spray
C1dReasons for Short Period CB
Chest infection (8) Acute exacerbation (COPD) (4) Acute decompensation (CHF) (3) Chemotherapy (3) Anemia Pleural effusion
CB ¼ continuous breathlessness; COPD ¼ chronic obstructive pulmonary disease; CHF ¼ chronic heart failure. In brackets: number of participants who report this trigger; no bracket ¼ report of one participant only.
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Fig. 1. Relationship between EB and CB. The uneven surface of the blue box should illustrate the variable intensity of continuous breathlessness (please refer the online version for colors). EB ¼ episodic breathlessness; CB ¼ continuous breathlessness.
one-third of the participants never smoked, and 14 of 51 needed oxygen supply. The mean severity of breathlessness over the last 24 hours was 3.2 (SD 1.7) on the modified Borg Scale (0e10) and at worst 5.4 (SD 2.4), with the highest numbers in patients with LC and the lowest in MND. The interviews mostly took place in participants’ homes (45 of 51) and lasted for a median of 55 minutes (range 17e89 minutes).
Differentiation Between Episodic Breathlessness and Continuous Breathlessness Participants differentiated episodic breathlessness and continuous breathlessness by time: episodic breathlessness was characterized
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as being breathless for seconds, minutes, or hours (less than 24 hours) and continuous breathlessness was described by breathlessness longer than 24 hours (days, weeks, months, or years). Terms for episodic breathlessness were the following: attack, acute breathlessness, crisis, episode, gradual, incident, increase, period, spasmodic, and spontaneous. For continuous breathlessness, participants used the following terminology: breathlessness, breathlessness at rest, breathlessness all the time, constant, constant variable, continuous, fluctuating, and bad days. Episodic breathlessness: The episode comes and goes as, as it will. (Male, 79 years, COPD) Continuous breathlessness: You’re always a bit breathless. (Male, 70 years, COPD) Participants described a clear relationship between episodic breathlessness and continuous breathlessness using two options: 1) episodic breathlessness only, without continuous breathlessness or 2) continuous breathlessness plus episodic breathlessness (including all subcategories). Participants did not describe continuous breathlessness without episodic breathlessness; 11 of 51 (22%) participants reported episodic breathlessness only, whereas
Fig. 2. Categorization of breathlessness by time and triggers based on patients’ experiences. EB ¼ episodic breathlessness; CB ¼ continuous breathlessness.
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Fig. 3. Main categories of breathlessness.
40 of 51 (78%) participants experienced both categories (Fig. 1).
Two Types of Episodic Breathlessness: Triggered and Non-Triggered Participants described episodic breathlessness as being breathless for a certain time (framed by onset and recovery). When participants were asked to report their experience of episodic breathlessness, they described two different subgroups based on the existence of a trigger as a differentiator. Episodic breathlessness could either be caused by a distinct trigger or have occurred ‘‘out of the blue’’ without any identifiable trigger. Participants reported different triggers causing breathlessness. The most common subcategory of triggered episodic breathlessness was exertional breathlessness. Different levels of exertion were described: some participants became breathless by the slightest exertion, for example, walking a few steps on flat ground or just by talking, whereas others experienced breathlessness only after climbing some stairs or lifting heavy loads. However, most experienced an aggravation or worsening of their underlying breathlessness by becoming much more breathless compared with a healthy person. Overall, the severity and length of episodic breathlessness was related to the exertional level, with slight exertion causing mild and short episodes of breathlessness and high levels of exertion causing severe and longer episodes of breathlessness. Participants with exertional breathlessness described long walks, climbing stairs, and talking as common triggers but emphasized that carrying or lifting something (not necessarily heavy loads), rushing, or bending over were specific triggers that caused breathlessness very quickly (Table 2, A1). Now my breathlessness starts just a bit when I am talking or, er, when I am going up and down. (Female, 84 years, lung cancer)
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In addition, episodic breathlessness could be triggered by emotions and emotions could worsen continuous breathlessness or exertional breathlessness, which led to emergency calls when episodes of breathlessness were getting out of control. Panic, anger, and excitement were the most common emotional triggers of episodic breathlessness (Table 2, A2). When you are getting angry about something that seems to trigger it off. (Female, 69 years, COPD) Panic makes it worse. (Male, 89 years, CHF) Other triggers (e.g., environmental factors) potentially causing episodic breathlessness were extreme temperature (both cold and hot), chemicals (e.g., perfume), certain positions (e.g., lying down), or dust (Table 2, A3). I can’t stand people with deodorants on and that affects me quite badly. (Male, 69 years, COPD) Forty-nine percent of participants reported episodic breathlessness that occurred without warning and was unpredictable (coming ‘‘out of the blue’’). No trigger could be identified, and episodes could not be related to a certain situation or time. It was often characterized by quick onset, short duration, and severe intensity. This non-triggered episodic breathlessness was more common in patients with COPD and less common in MND but occurred in all disease groups. Sitting, watching television and then all of a sudden it comes on like that with no reason at all. (Female, 74 years, LC) Participants described episodic breathlessness as being breathless for a certain time (framed by onset and recovery). In contrast, continuous breathlessness was experienced as breathlessness all the time without breathlessfree intervals.
Two Manifestations of Continuous Breathlessness: Short Period and Long Period Some participants experienced continuous breathlessness as breathlessness all the time and even at rest. Although they tried to suppress or forget the continuous impairment of their breathing, a certain level of continuous breathlessness was always present. However,
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participants described the intensity level not as a continuum but as variable and fluctuating. Even participants with very severe continuous breathlessness (e.g., 8/10 or 9/10) judged the continuous breathlessness intensity at rest quite low but sometimes the slightest exertion triggered a severe level of continuous breathlessness. In addition, participants described bad days when they were severely breathless alternating with better days when continuous breathlessness was not such a burden. It’s a variable constant. (Male, 65 years, lung cancer) Sometimes you have better days than others. (Male, 72 years, CHF) Two subcategories of continuous breathlessness could be differentiated by time. First, some participants experienced continuous breathlessness only over a short period (days or weeks), for example, when they suffered from a chest infection or exacerbation of COPD (Table 2, C1). Basically, these participants only had episodes of breathlessness (e.g., exertional breathlessness), but for a certain time during a chest infection they were breathless all day long and reported this as continuous breathlessness. Second, some participants reported being breathless all the time for a long period and were familiar with this situation for months or even years as a chronic condition (e.g., patients with COPD). Exacerbation of COPD during winter time: When I really am bad I just can’t talk, I just can’t breathe, I just can’t do anything. (Male, 79 years, COPD) Chronic condition: It is there all the time, it never goes away. [.] it’s fighting for your life all the time. (Male, 76 years, COPD)
Categorization of Breathlessness by Time and Trigger Participants’ experiences and descriptions of different categories and subcategories of breathlessness allow a categorization of breathlessness (Fig. 2). First, episodic breathlessness and continuous breathlessness can be differentiated by time: episodic breathlessness can be defined by the length of the episode in seconds, minutes, or hours, whereas continuous breathlessness is characterized by breathlessness over a long
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period of time, for example, days, weeks, months, or even years. Second, two subcategories of episodic breathlessness can be identified in relation to triggers. Episodic breathlessness can be triggered by a known cause (Adtriggered episodic breathlessness), for example, exertion, emotion, or others (A1e3), or episodic breathlessness can occur ‘‘out of the blue’’ without a known trigger (Bdnon-triggered episodic breathlessness). In addition, two subcategories of continuous breathlessness are differentiated by time: breathlessness over days or weeks, for example, caused by pleural effusion or chest infection (C1dshort period of continuous breathlessness) and breathlessness over months or years without an expected end (C2dlong period of continuous breathlessness) (Fig. 2). The term chronic breathlessness was used for the overall duration of patients’ experience of breathlessness (episodic and/or continuous breathlessness) over a period of months or longer. The median duration of participants’ experiences of breathlessness (episodic and/ or continuous breathlessness) was 24 months (range 1e420; n ¼ 48). The categories or subcategories of breathlessness that were most prevalent were: exertional breathlessness (A1), non-triggered episodic breathlessness (B), and continuous breathlessness over a long period best described as a ‘‘constant variable’’ (C2) (Fig. 3). The prevalence of all categories is listed in Table 3. All participants in our study experienced triggered episodic breathlessness (A1e3); 25 of 51 (50%) participants experienced non-triggered episodic breathlessness (B), with unpredictable breathlessness; and 40 of 51 (78%) participants described at least one subcategory of continuous breathlessness (C1 and/or C2). The prevalence varied between the four different disease groups but was more consistent for exertional breathlessness (A1) and continuous breathlessness over a long period (C2). Eight participants described all subcategories, and two participants referred to exertional breathlessness (A1) only.
Discussion This is the first study to categorize breathlessness based on patients’ experiences by time
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Table 3 Prevalence of Six Different Classification Groups of Breathlessness by Underlying Disease Disease Group
n
CHF, n (%) LC, n (%) COPD, n (%) MND, n (%) Total, n (%)
15 13 14 9 51
A1 (EB by Exertion) 15 13 14 8a 50
(100) (100) (100) (89) (98)
A2 (EB by Emotion) 10 8 11 2 31
(67) (62) (79) (22) (61)
A3 (EB by Environment) 5 8 11 8 32
B (Non-Triggered EB)
(33) (62) (79) (89) (63)
9 5 10 1 25
(60) (38) (71) (11) (49)
C1 (CB Short Period) 5 4 11 2 22
(33) (31) (79) (22) (43)
C2 (CB Long Period) 10 8 12 6 36
(67) (62) (86) (67) (71)
EB ¼ episodic breathlessness; CB ¼ continuous breathlessness; CHF ¼ chronic heart failure; LC ¼ lung cancer; COPD ¼ chronic obstructive pulmonary disease; MND ¼ motor neuron disease. a One patient with MND was quadriplegic, not able to exert and did not experience exertional breathlessness.
and triggers in patients with advanced disease, providing a new categorization for a better understanding of breathlessness. The main categories, episodic breathlessness and continuous breathlessness, can be differentiated by time using 24 hours as a preliminary cutoff and can be subcategorized into triggered and nontriggered episodic breathlessness and continuous breathlessness for short and long periods. These categories are clinically relevant and helpful for the assessment of breathless patients. In addition, the categorization of breathlessness will help to define patient groups in breathlessness research to evaluate and develop effective treatments and to compare studies accurately. The presented categorization of breathlessness, including subcategories and cutoffs, needs further verification and adaptation in clinical practice and surveys.
Time Episodic breathlessness and continuous breathlessness are discriminated by time using 24 hours as a cutoff, as participants characterized the duration of episodes of breathlessness only in seconds, minutes, and hours but never in days, weeks, or months. The only studies that evaluated the duration of episodes of breathlessness consistently described episodic breathlessness in minutes and hours (most frequently between 5 and 15 minutes).8,10,16 Our study supports these findings and suggests a cutoff (24 hours). Participants characterized episodic breathlessness as breathlessness with a beginning and an end. This also applies to longer periods of breathlessness over days or weeks, for example, when having a chest infection with severe breathlessness. As participants described the sensation of breathlessness during this period as continuous or all the time, we categorized
this as continuous breathlessness (short period of continuous breathlessness, C1 in Fig. 2). This subcategory also could be categorized in two different ways. First, it could be placed as a subcategory of episodic breathlessness because episodic breathlessness was preliminarily defined as ‘‘breathlessness occurring intermittently’’ with an onset and end, which also applies for C1. Second, it could be grouped as a third main category between episodic breathlessness and continuous breathlessness: episodic breathlessness (less than 24 hours), periodic breathlessness (days or weeks), and continuous breathlessness (months or years). We categorized C1 as a subcategory of continuous breathlessness because we used the dichotomous categories of episodic breathlessness and continuous breathlessness preliminarily and participants described C1 within this dichotomy as continuous breathlessness. However, we did not explore whether they would have preferred a third main category instead of the dichotomous categorization. To our knowledge, no study has used three main categories in the categorization of breathlessness. This needs further exploration in a future study.
Triggers Exertion was the most frequent trigger for episodes of breathlessness and described by all patients in this study (except one quadriplegic patient who was not able to exert). In participants with additional continuous breathlessness, sometimes the slightest exertion aggravated baseline levels of continuous breathlessness up to severe intensity resulting in limited mobility and high impact on daily life. The relevance of exertional breathlessness is frequently described.1 Episodic breathlessness by exertion is the main cause of breathlessness in patients with COPD.17,18 In
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reducing activity, patients try to prevent and relieve breathlessness, but this leads to inactivity and deconditioning, with a vicious cycle of worsening quality of life and social loss. Similar experiences were reported for patients with cancer, and exertional triggers have been identified as most common.8 There is increasing evidence and better understanding about the neurophysiological mechanisms of episodic breathlessness by exertion involving ventilator load, respiratory muscle capacity, neural respiratory drive, and neuromechanical dissociation.19 However, exertion not only triggers episodic breathlessness but also can increase exercise capacity when used appropriately, for example, during pulmonary rehabilitation for COPD patients.20 Finally, different levels of exertion or exercise capacity are used as measurement criteria in tools to evaluate breathlessness severity, for example, the Medical Research Council Breathlessness Scale or the Oxygen Cost Diagram.21 Therefore, the category episodic breathlessness by exertion or, in other words, the impairment of daily activity is used as an indicator for the severity of breathlessness in general. Besides exertion, a variety of triggers is known and has been described before, such as emotions (e.g., panic and anger) and environmental factors (e.g., cold wind and perfume). In our study, exertion and emotion were the most important and most prevalent triggers and could occur simultaneously and exacerbate each other, for example, being upset and rushing to the telephone. These situations can lead to severe episodes of breathlessness with the possibility of losing control of the situation and needing to call an ambulance. Our findings are supported by trigger lists of other studies and add some new factors.8,9,22,23
Non-Triggered Episodic Breathlessness Non-triggered episodic breathlessness has rarely been reported before. A recent systematic review on episodic breathlessness identified only four qualitative studies that mentioned this category, with limited information.7,16,17,24,25 In a sample of 18 COPD patients, some patients reported the sudden onset and rapid disappearance of episodic breathlessness without knowing the trigger (e.g., no exertion).24 In a mixed sample of
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COPD and cancer patients, only patients with cancer described unpredictable and inexplicable episodic breathlessness.7 In our study, nearly half of the patients reported this unpredictable form of episodic breathlessness, which occurred most often in patients with COPD and rarely in MND patients. It could be argued that participants might not remember the trigger or do not want to report the trigger (e.g., anxiety or panic).7 Although this might be the case in a few patients, it seems to be unlikely for all because of the consistency in reporting by half of the participants in this sample. Additionally, anxiety, panic, and other sensitive issues were frequent topics during the in-depth interviews with no correlation between this category of episodic breathlessness and patients who did not want to talk about sensitive issues.
Continuous Breathlessness as a ‘‘Constant Variable’’ Continuous breathlessness is a continuum in terms of ‘‘present all the time’’ but very variable and fluctuating regarding the intensity level. All triggers of episodic breathlessness (A1e3) and especially exertion can aggravate continuous breathlessness but so can changes in the daily condition. In a qualitative study on COPD patients, the ‘‘invisibility’’ of breathlessness was described when the patient seemed to be all right at rest (without breathlessness) but severely disabled by breathlessness during slightest exertion (walking to the bathroom).24 Mainly, participants with COPD reported this fluctuation in our study, but it occurred in all disease groups. The variability of continuous breathlessness is one reason why the management of breathlessness is challenging in finding the right balance in pharmacological treatment between overdosing and underdosing. Clinical experience and trial evidence suggest lower doses of morphine in the management of breathlessness in contrast to pain. A recent pharmacovigilance study with a mixed disease group of patients (predominantly COPD) showed that 10 mg sustained-released morphine once daily was effective for most patients.5 In addition and because of the variability of continuous breathlessness, measurement of breathlessness in clinical practice and in trials should cover breathlessness ‘‘over the past 24 hours’’ and not only ‘‘right now.’’26
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Strengths and Limitations One of the strengths of this study is that the provided categorization of breathlessness by time and triggers is based on patient experience and not just clinical observation. This advances our understanding of this complex symptom to inform appropriate and effective management. Second, patients from different disease groups were included in the study. This allows the proposed classification to be applicable in diseases with a high prevalence of breathlessness and not only to one disease. There also are some limitations. Although this was a qualitative study, we do present some numbers and proportions to give an indication of the distribution of the breathlessness categories in the different disease groups; however, the small numbers do not allow any statistical analysis. Therefore, the prevalence of different categories needs further verification in a larger survey with sufficient statistical power and higher numbers of participants. Episodic breathlessness in this study might have been overestimated and categories biased toward episodic breathlessness, as the main focus of the interviews was to explore experiences and characteristics of episodic breathlessness. However, participants were not only asked about episodic breathlessness but about their general experience with breathlessness (including continuous breathlessness) and how episodic breathlessness differed from continuous breathlessness.
Implications for Clinical Practice and Research First, breathless patients experience breathlessness in different ways and with different characteristics. We need to label these different patient experiences and develop a shared terminology among both clinicians and researchers to speak the same language. Therefore, a consensus about categories, definitions, and terminology is needed. Second, the categorization should help to describe the interrelation between categories as well as differentiators and cutoffs. This is most relevant for finding the most effective and most appropriate treatment because different categories might need different management strategies. Third, the categorization should inform the clinical assessment of breathless patients to evaluate from
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which kind of breathlessness the patient is suffering. The three main categories (Fig. 3) can lead clinical assessment. In addition, symptomatic management of breathlessness (episodic and continuous breathlessness) should always start with the evaluation of reversible triggers and optimization of the treatment of the underlying disease. The list of triggers (A1e3 and C1) might be helpful as a checklist. Fourth, the categorization should inform research to develop effective management strategies and for a better comparison of studies in the area of breathlessness using the same terminology and categories.
Conclusion We provide a new evidence-based categorization of breathlessness by time and triggers based on patient reports. The categorization needs further verification in larger surveys and a consensus about definitions and terminology similar to those already established in pain. Consistent, evidence-based, and clear definitions are a crucial foundation for research into effective interventions to optimize management.
Disclosures and Acknowledgments This study was supported by a research grant from the Dr. Werner Jachst€adt Foundation, Wuppertal, Germany and by Cicely Saunders International, London, U.K., without any influence on study design, analysis, interpretation, or presentation. The authors declare no conflicts of interest. The authors extend special thanks to all the patients who gave deep insights into their experiences of breathlessness. They thank Caroline Jolley, John Moxham, Julia DeCoursey, Andrew Dougherty, Nigel Leigh, and Emma Willey for their supportive recruitment of participants for this study and Cathy Shipman, Jonathan Koffman, Lucy Selman, Cassie Goddard, and Christina Ramsenthaler for their support during the analysis.
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