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Cardiac arrest and hypothermia treatment-function and life satisfaction among survivors in the first 6 months
Resuscitation 85 (2014) 538–543
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Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Clinical paper
Cardiac arrest and hypothermia treatment-function and life satisfaction among survivors in the first 6 months夽 Ewa Wallin a,∗ , Ing-Marie Larsson a , Sten Rubertsson a , Marja-Leena Kristofferzon b,c a b c
Department of Surgical Sciences-Anaesthesiology & Intensive Care, Uppsala University, SE- 751 85 Uppsala, Sweden Faculty of Health and Occupational Studies, Department of Health and Caring Sciences, University of Gävle, Sweden Department of Public Health and Caring Sciences, Uppsala University, Sweden
a r t i c l e
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Article history: Received 11 June 2013 Received in revised form 12 November 2013 Accepted 9 December 2013 Keywords: Cardiac arrest Hypothermia treatment Intensive care Neurological outcome Cognitive function Life satisfaction
a b s t r a c t Aim of the study: To describe differences over time in outcome, physical and cognitive function among survivors of cardiac arrest treated with hypothermia and to examine survivors’ life satisfaction 6 months after cardiac arrest as well as gender differences. Methods: The study was prospective and included 45 cardiac arrest survivors admitted to three Swedish hospitals between 2008 and 2012. Participants were followed from intensive care unit discharge to one and six months after cardiac arrest. In addition to cerebral performance category (CPC), participants were asked to complete questionnaires regarding activities in daily life (Barthel index), cognitive function (mini mental state examination), and life satisfaction (LiSat-11). Results: Outcome measured using CPC scores improved over time. At 6 months, all participants were classified as having a good outcome. At one month, participants were impaired but improved over time in their activities in daily life and cognitive function. At 6 months satisfaction with “life as a whole” was seen in 70%. Conclusions: Cardiac arrest survivors are satisfied with life as a whole despite a severe illness that has impaired their physical and cognitive function, which seemed to improve over time. Predicting patients’ functional outcome in early stages is difficult, and the CPC score alone is not sufficient to assess patients’ function. It is a need to reach a consensus to which instruments best reflect physical and cognitive function as well as to specify a rehabilitation plan. © 2013 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Return of spontaneous circulation (ROSC) is frequently followed by a post-resuscitation syndrome that may entail secondary neurological damages and other organ dysfunction.1,2 The severity of brain damage after cardiac arrest (CA) is influenced by several factors such as the length of the interruption of cerebral blood flow, the duration, and quality of resuscitation interventions as well as the patient’s age and the cause of the CA, all of which affect survival rate.3 Therapeutic hypothermia treatment (TH) (33 ◦ C ± 1) maintained for a period of 12–24 h post-CA has proven useful, thus to improving the neurological outcome and reducing mortality following CA.4,5 The purpose of resuscitation and subsequent
夽 A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2013.12.020. ∗ Corresponding author. Tel.: +46 18 6114840; fax: +46 18 507845. E-mail address: [email protected] (E. Wallin). 0300-9572/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.resuscitation.2013.12.020
hypothermia treatment is to regain the patient’s pre-CA health status. Life after CA survival is affected by and has been described as including severe fatigue, feelings of anxiety and/or depression, increased dependency in activities of daily life (ADL) and decreased QoL.6–9 Studies describing patients’ cognitive function, ADL, and life satisfaction after CA have measured physical and mental QoL and shown that cognitive complaints exist but do not always affect QoL, ADL or the ability to return to work.9–13 The majority of the previous studies have been cross-sectional and measurements have been performed between 3 months and 2 years post-CA. The aim of the present study was to describe differences over time regarding functional outcome using cerebral performance category (CPC) at discharge from the ICU and at 1 and 6 months after CA in cases where TH was used in postresuscitation care. Additional aims were to describe differences in ADL and cognitive function within 1 and 6 months postCA, life satisfaction 6 months after CA and possible gender differences.
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2. Material and methods 2.1. Inclusion criteria for TH This prospective observational study was part of a project performed at three intensive care units in Sweden between May, 2008 and May, 2012 and focused on survivors of CA. Eligible for inclusion were patients still comatose with a glasgow coma scale (GCS)14 <8 or a reaction level scale (RLS 85)15 >3 after successful ROSC, with a systolic arterial blood pressure ≥ 80 mmHg > 5 min, regardless of whether the CA occurred in or out of hospital, or initial to the ECG rhythm. Patients with suspected pregnancy, terminal illness and/or primary deranged coagulation, and age <18 years were excluded (Fig. 1). Before cooling, all patients were sedated, intubated, and ventilated according to guidelines for severely ill patients adapted for TH post-CA and according to the respective ICU routines. TH was induced at the emergency department or when the patient was admitted to the ICU and continued for 24 h followed by passiverewarming until the body temperature reached 36 ◦ C. The study protocol contained no guidelines for withholding or withdrawing treatment. The intensive care following CA follows the same priorities and ethical considerations as other intensive care, i.e., they are prioritized based on the function and prognosis of all vital organs, which decide whether active treatment is required or should be continued.16–18 Each ICU unit followed national recommendations which later have been published.17 2.2. Inclusion criteria for the follow-up study An overview of the whole inclusion and exclusion process is shown in Fig. 1. Inclusion criteria for the follow-up study were patients’ ability to: speak and understand the Swedish language, understand, and answer the questions used in the follow-up study and answer at least one of the questionnaires at both occasions. Among survivors, three patients with CPC 3–4 at both 1 and 6 months were not able to answer the questionnaires at any of these occasions. In addition, four patients with CPC 3–4 were excluded since they were not able to answer the questionnaires at 1 month (Fig. 1). 2.3. Data collection and procedures At 1 month post-CA, information on pre-CA socio-demographic variables was collected through self-reports or from relatives and the primary CA-related medical variables were collected from medical charts. At 6 months, information on work situation and healthcare visits was collected through self-reports. The outcome measurements were CPC19 , Barthel index (BI)20 , mini mental state examination (MMSE)21 , and life satisfaction (LiSat-11).22 The questionnaires contained four domains: functional outcome, ADL, cognitive function, and life satisfaction. CPC scores were obtained at discharge from ICU, and at 1 and 6 months after CA. At discharge from ICU, the CPC was assessed by the critical care physician and at 1 and 6 months by the study manager. Measurements of ADL, MMSE, and LiSat-11 were made within 1 month, and after 6 months post-CA in connection with a visit made by the study manager responsible for data collection in respective areas. 2.3.1. CPC CPC scores range from 1 to 5, with 1–2 representing good outcome and 5 representing death (Table 1).19 2.3.2. Activities in daily life (ADL) The BI produces a simple index of independence and is useful in scoring improvement in rehabilitation.20 The BI consists of 10
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variables measuring three categories of function: self-care, continence of bowel and bladder, and mobility. The total score range is from 0 to 100.20 A high score is associated with greater likelihood of being independent and able to live at home at discharge from hospital.20,23 The BI was used as a self-report instrument. 2.3.3. Mini mental state examination (MMSE) The MMSE is a quantitative screening instrument intended to evaluate the patient’s cognitive function.21 The first section includes orientation, memory, counting and attention, and requires a verbal response. The second section addresses the ability to follow written and oral instructions, type a phrase spontaneously and copy a figure. The score range is 0–30.21 Patients scoring below 24 are classified as having cognitive dysfunction.21 2.3.4. Life satisfaction checklist (LiSat-11) The LiSat-11 was used as a self-report instrument at 6 months after CA and encompasses eleven domains assessing overall and domain-specific life satisfaction.22 The first domain characterizes satisfaction “with life as a whole”. The remaining ten domains characterize vocational, financial, and leisure situations, social contacts, sexual and family life, self-care, partnership and somatic, and psychological health. The LiSat-11 uses a six-step ordinal self-rating scale ranging from 6 = very satisfying to 1 = very dissatisfying.22 The scores on the LiSat-11 were dichotomized into satisfying and very satisfying (5–6) and rather satisfying to very dissatisfying (1–4), which is considered a valid scale reduction.22 The instrument was validated in a representative sample of Swedish men and women aged 18–64 years.22 2.4. Statistical analysis Statistical analyses were performed using SPSS version 21 (SPSS Inc. Chicago, IL, USA). Descriptive statistics and results are presented as frequencies, percentages, and as means with standard deviations. Due to the small sample size, the Wilcoxon signed rank test and Friedman’s test were used to describe differences over time. The Mann Whitney U-test, Chi-square test and Fisher’s exact test were used to analyse differences between included and excluded patients as well as between genders. Given the multiple tests performed, a P-value ≤0.01 was considered statistically significant. The reliability of the instruments was expressed as Cronbach’s ␣ coefficient. 2.5. Ethical considerations The study was reviewed and approved by the Regional Ethical Review Board in Uppsala, Sweden (Reg. no. 2007/307). Participation was voluntary and participants were free to withdraw at any time. Written consent to participate was obtained from next of kin, and later from survivors. 3. Results A total of 45 participants were included in the follow-up study; the mean age was 64 and the majority were males. At the time of CA, 10 (22%) were working full time, 6 (13%) were working parttime, 28 (62%) were retired, and one (2%) was on sick-leave. At the 6-month follow-up 5 (11%) participants had returned to full-time work, 3 (7%) worked part time, 6 (13%) were still on sick-leave, and 31 (69%) were retired. Education level was equally distributed. Among the participants, 38 (84%) were married or living with a partner and 7 (16%) were living alone. The most common first registered ECG rhythm was VF/VT, the majority of CA events were witnessed and mean time to ROSC was 20 min. A majority of the participants had a history of heart disease prior to the CA (Table 2).
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Fig. 1. Flow chart of cardiac arrest (CA) patients admitted to intensive care unit (ICU).
Between 1 and 6 months post-CA, 27 (60%) participants visited the health care system and of these 13 (48%) had been readmitted to the hospital. Reasons for readmission were complications/events related to the implantable cardioverter defibrillator (ICD) in 4 (31%) participants, chest pain in 6 (46%), and respiratory and/or abdominal symptoms in 3 (23%). Stroke was more common among the excluded patients, which was the only difference found in medical history as compared to the included patients (Table 2).
3.1. CPC To provide an overview of the entire group all patients included (n = 125) were evaluated according to the CPC score at ICU discharge, 1 and 6 months (Table 3). At discharge from the ICU (n = 45) (mean 6 days), 10 (22%) participants were classified as CPC 1 and 25 (56%) were classified as CPC 2, i.e., good outcome. Ten (22%) participants were classified as CPC 3–4, i.e., poor outcome. Six participants who scored CPC 3 at discharge from ICU improved to CPC 1, and one participant who scored CPC 4 improved to CPC 2 at 6 month (Table 3). A Friedman test revealed that participants’
CPC score improved across the three assessment points: 2 (2, N = 45) = 56.673, p < 0.001. Differences were seen at 1 and 6 months between included and excluded patients (Table 3). 3.2. Activities in daily life (ADL) ADL measured using the BI improved (p = 0.01), and differences over time in total score were observed (Table 3). Areas of improvements were: bathing, mobility, transfer, and walking in stairs (Fig. 2). Differences were seen at 6 months (p = 0.002) between the CPC 1 and CPC 2 groups, where those with CPC 1 had a higher total score on BI. 3.3. Mini mental state examination (MMSE) Cognitive function measured using the MMSE showed improvements over time (p < 0.001) (Table 3). At 1 month post-CA, 17 (39.5%) participants scored <24, which indicates a cognitive dysfunction, nine (53%) participants were classified as CPC 1 and eight (47%) participants were classified as CPC 2. At 6 months post-CA five
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Table 1 Cerebral performance category (CPC) score and function level. CPC score
Function level
CPC 1 Good cerebral performance CPC 2 Moderate/good cerebral performance CPC 3 Severe cerebral disability
Normal life Conscious, alert, able to work and lead a normal life. May have minor psychological or neurologic deficit Disabled but independent Conscious. Sufficient cerebral function for part-time work in sheltered environment or independent activities of daily life. Conscious but disabled and dependent Dependent on others for daily support (in an institution or at home with exceptional family effort). Has at least limited cognition. This category includes a wide range of cerebral abnormalities Unconscious, unaware of surroundings, no cognition. No verbal or psychological interaction with environment.
CPC 4 Coma or vegetative state CPC 5 Death
Certified brain dead or dead by traditional criteria.
Table 2 Demographic and medical characteristics of the study sample.
Age: mean (SD) min–max Gender: number (%) Male Female Initial cardiac rhythm: number (%) VF/VT Asystole or PEA Unknown/missing Location of CA: number (%) OHCA IHCA Witnessed: number (%) Bystander: number (%) Time from collapse to ROSC: mean minutes (SD) min–max (n = 38) Time from CA to ≤ 34 ◦ C: mean minutes (SD), min–max Medical history: number (%) No previous illness Myocardial infarction Heart failure Hypertension Diabetes Lung disease Stroke Malignancy Time spent in ICU: mean days (SD), min–max Time spent in hospital to discharge: mean days (SD), min–max Education: number (%) Primary school High school University Unknown
Included in the follow-up study (n = 45)
Excluded from the follow-up study (n = 18)
P-value
64 (13) 24–85
67 (16) 23–82
(NS)
29 (64) 16 (36)
15 (83) 3 (17)
(NS)
30 (67) 9 (20) 6 (13)
7 (39) 8 (44) 3 (17)
30 (67) 15 (33) 43 (96) 27 (60) 20 (15) 5–90 355 (190) 30–920
10 (56) 8 (44) 15 (83) 10 (48) 18 (10) 5–40 392 (174) 95–715
(NS) – – – (NS) – – (NS) (NS) (NS) (NS)
11(26) 15(33) 13 (31) 20 (44) 7 (16) 8 (18) 0 (0) 0 (0) 6 (4) 2–17 16 (13) 1–58
5 (28) 7(39) 3 (17) 9 (50) 0 (0) 2 (11) 3 (17) 1 (5) 9 (10) 2–46 19 (19) 2–69
(NS) (NS) (NS) (NS) (NS)) (NS) 0,005 (NS) (NS) (NS)
a
18 (43) 13 (32) 10 (25) 1 (2)
– – – –
– – – –
VF = ventricular fibrillation, VT = ventricular tachycardia, PEA = pulseless electrical activity, OHCA = out of hospital cardiac arrest, IHCA = in hospital cardiac arrest, ROSC = return of spontaneous circulation, ICU = intensive care unit. NS = non significant a Was not examined among the excluded patients (n = 18). Table 3 Demonstrating the distribution of outcome variables (CPC, BI and MMSE) over time for included and excluded. ICU discharge
CPC, n (%) CPC 1 CPC 2 CPC 3 CPC 4 CPC 5 BI Mean (SD) Min–max MMSE, Mean (SD) Min–max
P-value
Excluded
Included
n= 80 1 (1) 9 (11) 5 (6) 3 (4) 62 (78) – – – – – – – –
n = 45 10 (22) 25 (56) 9 (20) 1 (2) – – – – – – – – –
0.089 – – – – – – – – – – – – –
1 month
P-value
Excluded
Included
n = 18 7(39) 4(22) 6 (33) 1 (6) – n=3 85 (25.9) 55–100 n=4 24.4 (3.21) 21–28
n = 45 30 (67) 15 (33) – – – n = 45 86.4 (22.5) 20–100 n = 43 24.9 (3.64) 18–30
0.001 – – – – – 0.69 – – – 0.54 – – –
6 months Excluded
Included
n = 18 8 (44) 3 (17) 5 (28) – 2 (11) n=4 88.7 (16.5) 65–100 n=6 26 (3.83) 20–30
n = 45 40 (89) 5 (11) – – – n = 45 93.6 (16) 15–100 n = 43 27.2 (3.5) 12–30
P-value
Cronbachs alpha values
0.001 – – – – – 0.16 – – – 0.07 – – –
– – – – – – 0.93–0.94 – – – 0.77–0.72 – – –
P-values for differences between included and excluded. Cerebral performance categories (CPC) Barthel index (BI), minimental state examination (MMSE).
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4. Discussion
Fig. 2. Overview over Barthel index (BI) over time (n = 45). Possible points range from 5 to 10 in the different areas of BI.5 points in; bathing, personal hygiene, 10 points in; eat/dink, dressing, bowel/bladder control, toilet use, walking in stairs,15 points in; mobility, transfer.
(11.6%) participants scored <24 of these two participant was classified as CPC 1 and three were classified as CPC 2. Improvements over time were predominantly seen in areas such as orientation difficulties (p = 0.001) recall (p = 0.001) and coping a figure (p = 0.004). Differences were seen in MMSE at 6 months (p = 0.001) between the CPC 1 and CPC 2 groups, where those with CPC 1 had a higher score on MMSE.
3.4. Life satisfaction (LiSat-11) Satisfaction with “life as a whole” was seen in 70% of participants at 6 months post-CA (Table 4). A majority of participants were satisfied with family life, partnership, economy, contacts, ADL, and psychological health. A lower degree of satisfaction was observed in the relation to sexual life, and fewer were satisfied with somatic health (Table 4). Gender differences were found in psychological health 2 (df = 1) = 6.2, p = 0.007 where more men than women indicated satisfaction. No differences were seen between the CPC 1 and CPC 2 groups. There were some missing data because all patients did not reply to all questionnaire items. Four patients indicated that they did not have a partner, which also can explain the missing data in the domain, sexual life (Table 4).
Table 4 Self-reported levels (%) of satisfaction with life as a whole and with 10 different domains using the LiSat-11 checklist (n = 43). LiSat-11 Satisfied with: Life as a whole Vocation (n = 41) Economy (n = 42) Leisure (n = 42) Contacts Sexual life (n = 39) ADL Family life Partner relationship (n = 39)a Somatic health (n = 41) Psychological health For the whole scale a
Those with partner.
Satisfied (5–6) n (%)
Dissatisfied (1–4) n (%)
Cronbach alpha
30 (70) 22 (54) 27 (64) 24 (57) 28 (65) 13 (33) 36 (84) 36 (84) 32 (76)
13 (30) 19 (46) 14 (36) 18 (43) 15 (35) 26 (67) 7 (16) 7 (16) 6 (14)
– – – – – – – – –
21 (51) 31 (72) –
20 (49) 12 (28) –
– – 0.86
Impairment in physical and cognitive function is common in hypothermia-treated CA survivors, but tends to decrease over time in this selected group of CA survivors. The excluded group scored lower in CPC, both at 1 and 6 months. We found improvements in CPC from ICU discharge to 6 months post-CA among the included patients. Our result is comparable with Bouwes et al., who reported that 53% of the patients remained with bad outcome at 6 months.24 However, other studies report fewer patients remaining with bad outcome from hospital discharge to 6–12 months post-CA.10,25 Our result may have been affected by the loss of patients but cannot be confirmed as we did not collect data among the excluded patients. In the present study, about half of the participants of working age had returned to work at 6 months. This is comparable with others where about 50–79% of CA survivors had returned to work 6–36 months post-CA.6,10,13,26 However, the mean age at the CA event was lower in two of the previous studies (52–57 years compared to 64 years in the present study).6,13 The majority of participants in the present study were retired or close to retirement at the time of the CA, which may reflect the ability to return to work. Furthermore, if the question regarding work had been posed at a longer post-CA interval, return-to-work rates might have been higher. All this indicates that time and age are important factors in CA survivors’ improvement. Change in BI over a set time can be a powerful predictor of rehabilitation.27 The total BI score is not the most meaningful measure, rather it is the breakdown into individual items describing specific deficiencies.20 Relatives have reported a lack of information on rehabilitation at hospital discharge because the CA survivors were not completely recovered at discharge.28,29 Therefore, information on the physical weaknesses revealed by BI scores could be helpful for relatives by prepare them for the kinds of assistance CA survivors will need. Relatives have described both physical and cognitive impacts in CA survivors.28 This is comparable with the present findings where deficits mainly occurred in orientation and recall. In the present study, participants’ cognitive function measured using the MMSE showed improvement over time. These participants were estimated as CPC 1–2 both at 1 and 6 month, which implies a good outcome. This shows that it is difficult to predict patients’ functional outcome in the early stages. It may also indicate that CPC is imprecise and that it is difficult to assess the patients’ capacity with CPC alone. Although improvements were observed in MMSE, it is a worse result compared to a previous study, that reported no patients with MMSE <24 post-CA.25 One reason for this difference could be that in the present study 20% of the participants had asystole as the initial ECG rhythm compared to Bro-Jeppesen et al., who had a selected group of patients where all had VF/VT as the initial rhythm.25 However, another study reported that 52% of the participants had MMSE < 24, 13–28 months post-CA, which is a higher percentage, compared with the present study where 11.6% scored <24, 6 months postCA.11 These variations of results suggest that it is unclear whether and when improvements decline after CA. According to LundgrenNilsson et al., there were no improvements in cognitive function between 45 days and 1 year after CA.7 All this suggests that neither the CPC nor the MMSE alone is sufficient to assess patients’ function.30–33 Lundgren-Nilsson et al. reported that life satisfaction measured using the LiSat-11 one year post-CA was much lower than that measured in the reference population.7 In the present study, functional, and cognitive impacts have minor effects on life satisfaction measured using the LiSat-11. This is consistent with a report by Cronberg et al., where minor cognitive impairments only had minor limited effects on functional status and QoL.10 Despite severe illness, 70% of participants in the present study reported being very satisfied or satisfied in the domain “life as a whole”, which is comparable with a representative sample of the Swedish
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population, where 70% were satisfied or very satisfied with their life.22 One strength of the present study was that patients were followed over time and time assessment was uniform. Both the BI and MMSE are well established and validated tools for screening for impairments over time; they are easy to perform and not time consuming.27,34 The assessment protocol was chosen to include both self-report and a face-to face-questionnaire to detect patients’ own estimation as well as to obtain an objective estimation of possible neurological deficits after CA. Still, the study has some limitations. First, the loss of patients in the follow-up due to patients’ health and logistic issues may have influenced the results, in that the results may reflect a selected group of patients with good outcomes post-CA and the results can therefore, not be generalized to apply all CA survivors. The inclusion of nine patients with CPC 3–4 in the present study supports the intension to include patients regardless of their CPC score. We included patients that could answer at least one of the instruments at both occasions since the aim was to analyze changes over time. Second, the MMSE is not a very sensitive test for detecting frontal lobe dysfunction in patients with preserved intellectual capacity and should not be used by itself as a diagnostic tool.10,33,34 Education level and age are two other factors that can affect the assessment of cognitive function.33 Fugate et al., used an instrument similar to MMSE, the telephone interview for cognitive status, modified (TICS-m) for CA-survivors and showed cognitive impairment in 40%, 14–24 months post-CA.26 TICS-M could therefore be an alternative to MMSE since the test can be conducted by telephone.26 Third, participants with impaired cognitive function might have answered the questions in a false positive way due to limitations in self-awareness. This could have been avoided by confirming their replies with a relative.23 In the present study eight participants had impairments in both BI and MMSE at 1 month and the number was reduced to half at 6 months. A relationship between low scores in CPC and high scores in BI and MMSE were seen both at 1 and 6 months after CA (rho = −0.41 to −0.45, p = 0.002 − 0.006), which indicate that these instruments may be valid, complement each other and might detect changes over time. 5. Conclusions It is difficult to predict patients’ functional outcome in the early stages, and single scoring instruments is not sufficient to assess patients’ function. Furthermore, the present findings indicate that time can be an important factor in patients’ recovery. This knowledge is important to pass on to the patient, relatives, and the rehabilitation team before discharge. Acknowledgements The authors thank RN Marie Sellert Rydberg Dept. of Anaesthesia & Intensive Care Falun for collaboration and data collection. We also wish to thank the Department of Surgical Sciences, Anaesthesiology & Intensive Care, Uppsala University, for institutional grants, and The Uppsala University Hospital and the Leardal Foundation for Acute Medicine for financial support. References 1. Laver SR, Padkin A, Atalla A, Nolan JP. Therapeutic hypothermia after cardiac arrest: a survey of practice in intensive care units in the United Kingdom. Anaesthesia 2006;61:873–7. 2. Safar P, Behringer W, Bottiger BW, Sterz F. Cerebral resuscitation potentials for cardiac arrest. Crit Care Med 2002;30:S140–4. 3. Herlitz J, Engdahl J, Svensson L, Young M, Angquist KA, Holmberg S. Can we define patients with no chance of survival after out-of-hospital cardiac arrest? Heart 2004;90:1114–8.
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J Psychiatr Res 1975;12:189–98. 22. Fugl-Meyer AR, Melin R, Fugl-Meyer KS. Life satisfaction in 18- to 64-year-old Swedes: in relation to gender, age, partner and immigrant status. J Rehabil Med 2002;34:239–46. 23. Collin C, Wade DT, Davies S, Horne V. The Barthel ADL index: a reliability study. Int Disabil Stud 1988;10:61–3. 24. Bouwes A, Binnekade JM, Kuiper MA, et al. Prognosis of coma after therapeutic hypothermia: a prospective cohort study. Ann neurol 2012;71:206– 12. 25. Bro-Jeppesen J, Kjaergaard J, Horsted TI, et al. The impact of therapeutic hypothermia on neurological function and quality of life after cardiac arrest. Resuscitation 2009;80:171–6. 26. Fugate JE, Moore SA, Knopman DS, et al. Cognitive outcomes of patients undergoing therapeutic hypothermia after cardiac arrest. Neurology 2013;81:40–5. 27. Quinn TJ, Langhorne P, Stott DJ. Barthel index for stroke trials: development, properties, and application. Stroke 2011;42:1146–51. 28. Wallin E, Larsson IM, Rubertsson S, Kristoferzon ML. Relatives’ experiences of everyday life six months after hypothermia treatment of a significant other’s cardiac arrest. J Clin Nurs 2013. 29. Larsson IM, Wallin E, Rubertsson S, Kristofferzon ML. Relatives’ experiences during the next of kin’s hospital stay after surviving cardiac arrest and therapeutic hypothermia. Eur J Cardiovas Nurs: J Working Group Cardiovas Nurs Eur Soc Cardiol 2012. 30. Stiell IG, Nesbitt LP, Nichol G, et al. Comparison of the cerebral performance category score and the health utilities index for survivors of cardiac arrest. Ann emerg med 2009;53:241–8. 31. Hsu JW, Madsen CD, Callaham ML. Quality-of-life and formal functional testing of survivors of out-of-hospital cardiac arrest correlates poorly with traditional neurologic outcome scales. Ann emerg med 1996;28:597–605. 32. Cummins RO, Chamberlain D, Hazinski MF, et al. Recommended guidelines for reviewing, reporting, and conducting research on in-hospital resuscitation: the in-hospital “Utstein style”. American Heart Association. Circulation 1997;95:2213–39. 33. Crum RM, Anthony JC, Bassett SS, Folstein MF. Population-based norms for the mini-mental state examination by age and educational level. J Am Med Ass 1993;269:2386–91. 34. Tombaugh TN, McIntyre NJ. The mini-mental state examination: a comprehensive review. J Am Geriatr Soc 1992;40:922–35.
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Clinical paper
Cardiac arrest and hypothermia treatment-function and life satisfaction among survivors in the first 6 months夽 Ewa Wallin a,∗ , Ing-Marie Larsson a , Sten Rubertsson a , Marja-Leena Kristofferzon b,c a b c
Department of Surgical Sciences-Anaesthesiology & Intensive Care, Uppsala University, SE- 751 85 Uppsala, Sweden Faculty of Health and Occupational Studies, Department of Health and Caring Sciences, University of Gävle, Sweden Department of Public Health and Caring Sciences, Uppsala University, Sweden
a r t i c l e
i n f o
Article history: Received 11 June 2013 Received in revised form 12 November 2013 Accepted 9 December 2013 Keywords: Cardiac arrest Hypothermia treatment Intensive care Neurological outcome Cognitive function Life satisfaction
a b s t r a c t Aim of the study: To describe differences over time in outcome, physical and cognitive function among survivors of cardiac arrest treated with hypothermia and to examine survivors’ life satisfaction 6 months after cardiac arrest as well as gender differences. Methods: The study was prospective and included 45 cardiac arrest survivors admitted to three Swedish hospitals between 2008 and 2012. Participants were followed from intensive care unit discharge to one and six months after cardiac arrest. In addition to cerebral performance category (CPC), participants were asked to complete questionnaires regarding activities in daily life (Barthel index), cognitive function (mini mental state examination), and life satisfaction (LiSat-11). Results: Outcome measured using CPC scores improved over time. At 6 months, all participants were classified as having a good outcome. At one month, participants were impaired but improved over time in their activities in daily life and cognitive function. At 6 months satisfaction with “life as a whole” was seen in 70%. Conclusions: Cardiac arrest survivors are satisfied with life as a whole despite a severe illness that has impaired their physical and cognitive function, which seemed to improve over time. Predicting patients’ functional outcome in early stages is difficult, and the CPC score alone is not sufficient to assess patients’ function. It is a need to reach a consensus to which instruments best reflect physical and cognitive function as well as to specify a rehabilitation plan. © 2013 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Return of spontaneous circulation (ROSC) is frequently followed by a post-resuscitation syndrome that may entail secondary neurological damages and other organ dysfunction.1,2 The severity of brain damage after cardiac arrest (CA) is influenced by several factors such as the length of the interruption of cerebral blood flow, the duration, and quality of resuscitation interventions as well as the patient’s age and the cause of the CA, all of which affect survival rate.3 Therapeutic hypothermia treatment (TH) (33 ◦ C ± 1) maintained for a period of 12–24 h post-CA has proven useful, thus to improving the neurological outcome and reducing mortality following CA.4,5 The purpose of resuscitation and subsequent
夽 A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2013.12.020. ∗ Corresponding author. Tel.: +46 18 6114840; fax: +46 18 507845. E-mail address: [email protected] (E. Wallin). 0300-9572/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.resuscitation.2013.12.020
hypothermia treatment is to regain the patient’s pre-CA health status. Life after CA survival is affected by and has been described as including severe fatigue, feelings of anxiety and/or depression, increased dependency in activities of daily life (ADL) and decreased QoL.6–9 Studies describing patients’ cognitive function, ADL, and life satisfaction after CA have measured physical and mental QoL and shown that cognitive complaints exist but do not always affect QoL, ADL or the ability to return to work.9–13 The majority of the previous studies have been cross-sectional and measurements have been performed between 3 months and 2 years post-CA. The aim of the present study was to describe differences over time regarding functional outcome using cerebral performance category (CPC) at discharge from the ICU and at 1 and 6 months after CA in cases where TH was used in postresuscitation care. Additional aims were to describe differences in ADL and cognitive function within 1 and 6 months postCA, life satisfaction 6 months after CA and possible gender differences.
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2. Material and methods 2.1. Inclusion criteria for TH This prospective observational study was part of a project performed at three intensive care units in Sweden between May, 2008 and May, 2012 and focused on survivors of CA. Eligible for inclusion were patients still comatose with a glasgow coma scale (GCS)14 <8 or a reaction level scale (RLS 85)15 >3 after successful ROSC, with a systolic arterial blood pressure ≥ 80 mmHg > 5 min, regardless of whether the CA occurred in or out of hospital, or initial to the ECG rhythm. Patients with suspected pregnancy, terminal illness and/or primary deranged coagulation, and age <18 years were excluded (Fig. 1). Before cooling, all patients were sedated, intubated, and ventilated according to guidelines for severely ill patients adapted for TH post-CA and according to the respective ICU routines. TH was induced at the emergency department or when the patient was admitted to the ICU and continued for 24 h followed by passiverewarming until the body temperature reached 36 ◦ C. The study protocol contained no guidelines for withholding or withdrawing treatment. The intensive care following CA follows the same priorities and ethical considerations as other intensive care, i.e., they are prioritized based on the function and prognosis of all vital organs, which decide whether active treatment is required or should be continued.16–18 Each ICU unit followed national recommendations which later have been published.17 2.2. Inclusion criteria for the follow-up study An overview of the whole inclusion and exclusion process is shown in Fig. 1. Inclusion criteria for the follow-up study were patients’ ability to: speak and understand the Swedish language, understand, and answer the questions used in the follow-up study and answer at least one of the questionnaires at both occasions. Among survivors, three patients with CPC 3–4 at both 1 and 6 months were not able to answer the questionnaires at any of these occasions. In addition, four patients with CPC 3–4 were excluded since they were not able to answer the questionnaires at 1 month (Fig. 1). 2.3. Data collection and procedures At 1 month post-CA, information on pre-CA socio-demographic variables was collected through self-reports or from relatives and the primary CA-related medical variables were collected from medical charts. At 6 months, information on work situation and healthcare visits was collected through self-reports. The outcome measurements were CPC19 , Barthel index (BI)20 , mini mental state examination (MMSE)21 , and life satisfaction (LiSat-11).22 The questionnaires contained four domains: functional outcome, ADL, cognitive function, and life satisfaction. CPC scores were obtained at discharge from ICU, and at 1 and 6 months after CA. At discharge from ICU, the CPC was assessed by the critical care physician and at 1 and 6 months by the study manager. Measurements of ADL, MMSE, and LiSat-11 were made within 1 month, and after 6 months post-CA in connection with a visit made by the study manager responsible for data collection in respective areas. 2.3.1. CPC CPC scores range from 1 to 5, with 1–2 representing good outcome and 5 representing death (Table 1).19 2.3.2. Activities in daily life (ADL) The BI produces a simple index of independence and is useful in scoring improvement in rehabilitation.20 The BI consists of 10
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variables measuring three categories of function: self-care, continence of bowel and bladder, and mobility. The total score range is from 0 to 100.20 A high score is associated with greater likelihood of being independent and able to live at home at discharge from hospital.20,23 The BI was used as a self-report instrument. 2.3.3. Mini mental state examination (MMSE) The MMSE is a quantitative screening instrument intended to evaluate the patient’s cognitive function.21 The first section includes orientation, memory, counting and attention, and requires a verbal response. The second section addresses the ability to follow written and oral instructions, type a phrase spontaneously and copy a figure. The score range is 0–30.21 Patients scoring below 24 are classified as having cognitive dysfunction.21 2.3.4. Life satisfaction checklist (LiSat-11) The LiSat-11 was used as a self-report instrument at 6 months after CA and encompasses eleven domains assessing overall and domain-specific life satisfaction.22 The first domain characterizes satisfaction “with life as a whole”. The remaining ten domains characterize vocational, financial, and leisure situations, social contacts, sexual and family life, self-care, partnership and somatic, and psychological health. The LiSat-11 uses a six-step ordinal self-rating scale ranging from 6 = very satisfying to 1 = very dissatisfying.22 The scores on the LiSat-11 were dichotomized into satisfying and very satisfying (5–6) and rather satisfying to very dissatisfying (1–4), which is considered a valid scale reduction.22 The instrument was validated in a representative sample of Swedish men and women aged 18–64 years.22 2.4. Statistical analysis Statistical analyses were performed using SPSS version 21 (SPSS Inc. Chicago, IL, USA). Descriptive statistics and results are presented as frequencies, percentages, and as means with standard deviations. Due to the small sample size, the Wilcoxon signed rank test and Friedman’s test were used to describe differences over time. The Mann Whitney U-test, Chi-square test and Fisher’s exact test were used to analyse differences between included and excluded patients as well as between genders. Given the multiple tests performed, a P-value ≤0.01 was considered statistically significant. The reliability of the instruments was expressed as Cronbach’s ␣ coefficient. 2.5. Ethical considerations The study was reviewed and approved by the Regional Ethical Review Board in Uppsala, Sweden (Reg. no. 2007/307). Participation was voluntary and participants were free to withdraw at any time. Written consent to participate was obtained from next of kin, and later from survivors. 3. Results A total of 45 participants were included in the follow-up study; the mean age was 64 and the majority were males. At the time of CA, 10 (22%) were working full time, 6 (13%) were working parttime, 28 (62%) were retired, and one (2%) was on sick-leave. At the 6-month follow-up 5 (11%) participants had returned to full-time work, 3 (7%) worked part time, 6 (13%) were still on sick-leave, and 31 (69%) were retired. Education level was equally distributed. Among the participants, 38 (84%) were married or living with a partner and 7 (16%) were living alone. The most common first registered ECG rhythm was VF/VT, the majority of CA events were witnessed and mean time to ROSC was 20 min. A majority of the participants had a history of heart disease prior to the CA (Table 2).
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Fig. 1. Flow chart of cardiac arrest (CA) patients admitted to intensive care unit (ICU).
Between 1 and 6 months post-CA, 27 (60%) participants visited the health care system and of these 13 (48%) had been readmitted to the hospital. Reasons for readmission were complications/events related to the implantable cardioverter defibrillator (ICD) in 4 (31%) participants, chest pain in 6 (46%), and respiratory and/or abdominal symptoms in 3 (23%). Stroke was more common among the excluded patients, which was the only difference found in medical history as compared to the included patients (Table 2).
3.1. CPC To provide an overview of the entire group all patients included (n = 125) were evaluated according to the CPC score at ICU discharge, 1 and 6 months (Table 3). At discharge from the ICU (n = 45) (mean 6 days), 10 (22%) participants were classified as CPC 1 and 25 (56%) were classified as CPC 2, i.e., good outcome. Ten (22%) participants were classified as CPC 3–4, i.e., poor outcome. Six participants who scored CPC 3 at discharge from ICU improved to CPC 1, and one participant who scored CPC 4 improved to CPC 2 at 6 month (Table 3). A Friedman test revealed that participants’
CPC score improved across the three assessment points: 2 (2, N = 45) = 56.673, p < 0.001. Differences were seen at 1 and 6 months between included and excluded patients (Table 3). 3.2. Activities in daily life (ADL) ADL measured using the BI improved (p = 0.01), and differences over time in total score were observed (Table 3). Areas of improvements were: bathing, mobility, transfer, and walking in stairs (Fig. 2). Differences were seen at 6 months (p = 0.002) between the CPC 1 and CPC 2 groups, where those with CPC 1 had a higher total score on BI. 3.3. Mini mental state examination (MMSE) Cognitive function measured using the MMSE showed improvements over time (p < 0.001) (Table 3). At 1 month post-CA, 17 (39.5%) participants scored <24, which indicates a cognitive dysfunction, nine (53%) participants were classified as CPC 1 and eight (47%) participants were classified as CPC 2. At 6 months post-CA five
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Table 1 Cerebral performance category (CPC) score and function level. CPC score
Function level
CPC 1 Good cerebral performance CPC 2 Moderate/good cerebral performance CPC 3 Severe cerebral disability
Normal life Conscious, alert, able to work and lead a normal life. May have minor psychological or neurologic deficit Disabled but independent Conscious. Sufficient cerebral function for part-time work in sheltered environment or independent activities of daily life. Conscious but disabled and dependent Dependent on others for daily support (in an institution or at home with exceptional family effort). Has at least limited cognition. This category includes a wide range of cerebral abnormalities Unconscious, unaware of surroundings, no cognition. No verbal or psychological interaction with environment.
CPC 4 Coma or vegetative state CPC 5 Death
Certified brain dead or dead by traditional criteria.
Table 2 Demographic and medical characteristics of the study sample.
Age: mean (SD) min–max Gender: number (%) Male Female Initial cardiac rhythm: number (%) VF/VT Asystole or PEA Unknown/missing Location of CA: number (%) OHCA IHCA Witnessed: number (%) Bystander: number (%) Time from collapse to ROSC: mean minutes (SD) min–max (n = 38) Time from CA to ≤ 34 ◦ C: mean minutes (SD), min–max Medical history: number (%) No previous illness Myocardial infarction Heart failure Hypertension Diabetes Lung disease Stroke Malignancy Time spent in ICU: mean days (SD), min–max Time spent in hospital to discharge: mean days (SD), min–max Education: number (%) Primary school High school University Unknown
Included in the follow-up study (n = 45)
Excluded from the follow-up study (n = 18)
P-value
64 (13) 24–85
67 (16) 23–82
(NS)
29 (64) 16 (36)
15 (83) 3 (17)
(NS)
30 (67) 9 (20) 6 (13)
7 (39) 8 (44) 3 (17)
30 (67) 15 (33) 43 (96) 27 (60) 20 (15) 5–90 355 (190) 30–920
10 (56) 8 (44) 15 (83) 10 (48) 18 (10) 5–40 392 (174) 95–715
(NS) – – – (NS) – – (NS) (NS) (NS) (NS)
11(26) 15(33) 13 (31) 20 (44) 7 (16) 8 (18) 0 (0) 0 (0) 6 (4) 2–17 16 (13) 1–58
5 (28) 7(39) 3 (17) 9 (50) 0 (0) 2 (11) 3 (17) 1 (5) 9 (10) 2–46 19 (19) 2–69
(NS) (NS) (NS) (NS) (NS)) (NS) 0,005 (NS) (NS) (NS)
a
18 (43) 13 (32) 10 (25) 1 (2)
– – – –
– – – –
VF = ventricular fibrillation, VT = ventricular tachycardia, PEA = pulseless electrical activity, OHCA = out of hospital cardiac arrest, IHCA = in hospital cardiac arrest, ROSC = return of spontaneous circulation, ICU = intensive care unit. NS = non significant a Was not examined among the excluded patients (n = 18). Table 3 Demonstrating the distribution of outcome variables (CPC, BI and MMSE) over time for included and excluded. ICU discharge
CPC, n (%) CPC 1 CPC 2 CPC 3 CPC 4 CPC 5 BI Mean (SD) Min–max MMSE, Mean (SD) Min–max
P-value
Excluded
Included
n= 80 1 (1) 9 (11) 5 (6) 3 (4) 62 (78) – – – – – – – –
n = 45 10 (22) 25 (56) 9 (20) 1 (2) – – – – – – – – –
0.089 – – – – – – – – – – – – –
1 month
P-value
Excluded
Included
n = 18 7(39) 4(22) 6 (33) 1 (6) – n=3 85 (25.9) 55–100 n=4 24.4 (3.21) 21–28
n = 45 30 (67) 15 (33) – – – n = 45 86.4 (22.5) 20–100 n = 43 24.9 (3.64) 18–30
0.001 – – – – – 0.69 – – – 0.54 – – –
6 months Excluded
Included
n = 18 8 (44) 3 (17) 5 (28) – 2 (11) n=4 88.7 (16.5) 65–100 n=6 26 (3.83) 20–30
n = 45 40 (89) 5 (11) – – – n = 45 93.6 (16) 15–100 n = 43 27.2 (3.5) 12–30
P-value
Cronbachs alpha values
0.001 – – – – – 0.16 – – – 0.07 – – –
– – – – – – 0.93–0.94 – – – 0.77–0.72 – – –
P-values for differences between included and excluded. Cerebral performance categories (CPC) Barthel index (BI), minimental state examination (MMSE).
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4. Discussion
Fig. 2. Overview over Barthel index (BI) over time (n = 45). Possible points range from 5 to 10 in the different areas of BI.5 points in; bathing, personal hygiene, 10 points in; eat/dink, dressing, bowel/bladder control, toilet use, walking in stairs,15 points in; mobility, transfer.
(11.6%) participants scored <24 of these two participant was classified as CPC 1 and three were classified as CPC 2. Improvements over time were predominantly seen in areas such as orientation difficulties (p = 0.001) recall (p = 0.001) and coping a figure (p = 0.004). Differences were seen in MMSE at 6 months (p = 0.001) between the CPC 1 and CPC 2 groups, where those with CPC 1 had a higher score on MMSE.
3.4. Life satisfaction (LiSat-11) Satisfaction with “life as a whole” was seen in 70% of participants at 6 months post-CA (Table 4). A majority of participants were satisfied with family life, partnership, economy, contacts, ADL, and psychological health. A lower degree of satisfaction was observed in the relation to sexual life, and fewer were satisfied with somatic health (Table 4). Gender differences were found in psychological health 2 (df = 1) = 6.2, p = 0.007 where more men than women indicated satisfaction. No differences were seen between the CPC 1 and CPC 2 groups. There were some missing data because all patients did not reply to all questionnaire items. Four patients indicated that they did not have a partner, which also can explain the missing data in the domain, sexual life (Table 4).
Table 4 Self-reported levels (%) of satisfaction with life as a whole and with 10 different domains using the LiSat-11 checklist (n = 43). LiSat-11 Satisfied with: Life as a whole Vocation (n = 41) Economy (n = 42) Leisure (n = 42) Contacts Sexual life (n = 39) ADL Family life Partner relationship (n = 39)a Somatic health (n = 41) Psychological health For the whole scale a
Those with partner.
Satisfied (5–6) n (%)
Dissatisfied (1–4) n (%)
Cronbach alpha
30 (70) 22 (54) 27 (64) 24 (57) 28 (65) 13 (33) 36 (84) 36 (84) 32 (76)
13 (30) 19 (46) 14 (36) 18 (43) 15 (35) 26 (67) 7 (16) 7 (16) 6 (14)
– – – – – – – – –
21 (51) 31 (72) –
20 (49) 12 (28) –
– – 0.86
Impairment in physical and cognitive function is common in hypothermia-treated CA survivors, but tends to decrease over time in this selected group of CA survivors. The excluded group scored lower in CPC, both at 1 and 6 months. We found improvements in CPC from ICU discharge to 6 months post-CA among the included patients. Our result is comparable with Bouwes et al., who reported that 53% of the patients remained with bad outcome at 6 months.24 However, other studies report fewer patients remaining with bad outcome from hospital discharge to 6–12 months post-CA.10,25 Our result may have been affected by the loss of patients but cannot be confirmed as we did not collect data among the excluded patients. In the present study, about half of the participants of working age had returned to work at 6 months. This is comparable with others where about 50–79% of CA survivors had returned to work 6–36 months post-CA.6,10,13,26 However, the mean age at the CA event was lower in two of the previous studies (52–57 years compared to 64 years in the present study).6,13 The majority of participants in the present study were retired or close to retirement at the time of the CA, which may reflect the ability to return to work. Furthermore, if the question regarding work had been posed at a longer post-CA interval, return-to-work rates might have been higher. All this indicates that time and age are important factors in CA survivors’ improvement. Change in BI over a set time can be a powerful predictor of rehabilitation.27 The total BI score is not the most meaningful measure, rather it is the breakdown into individual items describing specific deficiencies.20 Relatives have reported a lack of information on rehabilitation at hospital discharge because the CA survivors were not completely recovered at discharge.28,29 Therefore, information on the physical weaknesses revealed by BI scores could be helpful for relatives by prepare them for the kinds of assistance CA survivors will need. Relatives have described both physical and cognitive impacts in CA survivors.28 This is comparable with the present findings where deficits mainly occurred in orientation and recall. In the present study, participants’ cognitive function measured using the MMSE showed improvement over time. These participants were estimated as CPC 1–2 both at 1 and 6 month, which implies a good outcome. This shows that it is difficult to predict patients’ functional outcome in the early stages. It may also indicate that CPC is imprecise and that it is difficult to assess the patients’ capacity with CPC alone. Although improvements were observed in MMSE, it is a worse result compared to a previous study, that reported no patients with MMSE <24 post-CA.25 One reason for this difference could be that in the present study 20% of the participants had asystole as the initial ECG rhythm compared to Bro-Jeppesen et al., who had a selected group of patients where all had VF/VT as the initial rhythm.25 However, another study reported that 52% of the participants had MMSE < 24, 13–28 months post-CA, which is a higher percentage, compared with the present study where 11.6% scored <24, 6 months postCA.11 These variations of results suggest that it is unclear whether and when improvements decline after CA. According to LundgrenNilsson et al., there were no improvements in cognitive function between 45 days and 1 year after CA.7 All this suggests that neither the CPC nor the MMSE alone is sufficient to assess patients’ function.30–33 Lundgren-Nilsson et al. reported that life satisfaction measured using the LiSat-11 one year post-CA was much lower than that measured in the reference population.7 In the present study, functional, and cognitive impacts have minor effects on life satisfaction measured using the LiSat-11. This is consistent with a report by Cronberg et al., where minor cognitive impairments only had minor limited effects on functional status and QoL.10 Despite severe illness, 70% of participants in the present study reported being very satisfied or satisfied in the domain “life as a whole”, which is comparable with a representative sample of the Swedish
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population, where 70% were satisfied or very satisfied with their life.22 One strength of the present study was that patients were followed over time and time assessment was uniform. Both the BI and MMSE are well established and validated tools for screening for impairments over time; they are easy to perform and not time consuming.27,34 The assessment protocol was chosen to include both self-report and a face-to face-questionnaire to detect patients’ own estimation as well as to obtain an objective estimation of possible neurological deficits after CA. Still, the study has some limitations. First, the loss of patients in the follow-up due to patients’ health and logistic issues may have influenced the results, in that the results may reflect a selected group of patients with good outcomes post-CA and the results can therefore, not be generalized to apply all CA survivors. The inclusion of nine patients with CPC 3–4 in the present study supports the intension to include patients regardless of their CPC score. We included patients that could answer at least one of the instruments at both occasions since the aim was to analyze changes over time. Second, the MMSE is not a very sensitive test for detecting frontal lobe dysfunction in patients with preserved intellectual capacity and should not be used by itself as a diagnostic tool.10,33,34 Education level and age are two other factors that can affect the assessment of cognitive function.33 Fugate et al., used an instrument similar to MMSE, the telephone interview for cognitive status, modified (TICS-m) for CA-survivors and showed cognitive impairment in 40%, 14–24 months post-CA.26 TICS-M could therefore be an alternative to MMSE since the test can be conducted by telephone.26 Third, participants with impaired cognitive function might have answered the questions in a false positive way due to limitations in self-awareness. This could have been avoided by confirming their replies with a relative.23 In the present study eight participants had impairments in both BI and MMSE at 1 month and the number was reduced to half at 6 months. A relationship between low scores in CPC and high scores in BI and MMSE were seen both at 1 and 6 months after CA (rho = −0.41 to −0.45, p = 0.002 − 0.006), which indicate that these instruments may be valid, complement each other and might detect changes over time. 5. Conclusions It is difficult to predict patients’ functional outcome in the early stages, and single scoring instruments is not sufficient to assess patients’ function. Furthermore, the present findings indicate that time can be an important factor in patients’ recovery. This knowledge is important to pass on to the patient, relatives, and the rehabilitation team before discharge. Acknowledgements The authors thank RN Marie Sellert Rydberg Dept. of Anaesthesia & Intensive Care Falun for collaboration and data collection. We also wish to thank the Department of Surgical Sciences, Anaesthesiology & Intensive Care, Uppsala University, for institutional grants, and The Uppsala University Hospital and the Leardal Foundation for Acute Medicine for financial support. References 1. Laver SR, Padkin A, Atalla A, Nolan JP. Therapeutic hypothermia after cardiac arrest: a survey of practice in intensive care units in the United Kingdom. Anaesthesia 2006;61:873–7. 2. Safar P, Behringer W, Bottiger BW, Sterz F. Cerebral resuscitation potentials for cardiac arrest. Crit Care Med 2002;30:S140–4. 3. Herlitz J, Engdahl J, Svensson L, Young M, Angquist KA, Holmberg S. Can we define patients with no chance of survival after out-of-hospital cardiac arrest? Heart 2004;90:1114–8.
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