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Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy
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Intensive and Critical Care Nursing (2015) xxx, xxx—xxx
Available online at www.sciencedirect.com
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Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy Glenn M. Eastwood a,∗, Leah Peck a, Helen Young a, Emily Paton a, Neil J. Glassford a, Ling Zhang b, Guijun Zhu c, Aiko Tanaka a, Rinaldo Bellomo a a
Department of Intensive Care, Austin Hospital, Victoria, Australia Department of Nephrology, West China Medical School, West China Hospital, Sichuan, China c Department of Intensive Care, The Fourth Hospital of Hebei Austin Hospital, Hebei, China b
Accepted 1 June 2015
KEYWORDS Acute care nursing; Bolus fluid therapy; Fluid resuscitation; Decision-making; Intravenous fluid
Summary Objective: To describe self-reported practice of fluid bolus therapy by intensive care nurses. Research methodology: Multi-choice questionnaire of intensive care nurses conducted in July, 2014. Setting: Major university tertiary referral centre. Findings: 141 (64%) intensive care nurses responded. The majority of respondents identified 4% albumin as the commonest fluid bolus type and stated a fluid bolus was 250 ml; however fluid bolus volume varied from 100 ml to 1000 ml. Hypotension was identified as the primary physiological trigger for a fluid bolus. In the hour following a fluid bolus for hypotension almost half of respondents expected an ‘increase in mean arterial pressure of 0—10 mmHg’; for oliguria, >60% expected an ‘increase in urinary output of ‘0.5—1 ml/kg/hour’; for low CVP, 50% expected ‘an increase in CVP of 3—4 mmHg’; and, for tachycardia, 45% expected a ‘decrease in heart rate of 11—20 beats/minute’. Finally, 7—10% of respondents were ‘unsure’ about the physiological response to a fluid bolus.
∗
Corresponding author. Tel.: +61 3 9496 4835; fax: +61 3 9496 3932. E-mail addresses: [email protected] (G.M. Eastwood), [email protected] (L. Peck), [email protected] (H. Young), [email protected] (E. Paton), [email protected] (N.J. Glassford), [email protected] (L. Zhang), [email protected] (G. Zhu), [email protected] (A. Tanaka), [email protected] (R. Bellomo). http://dx.doi.org/10.1016/j.iccn.2015.06.001 0964-3397/© 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Eastwood GM, et al. Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy. Intensive Crit Care Nurs (2015), http://dx.doi.org/10.1016/j.iccn.2015.06.001
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G.M. Eastwood et al. Conclusion: Most respondents identified fluid bolus therapy to be at least 250 ml of 4% albumin given as quickly as possible; however, volumes from 100 to 1000 ml were also accepted. There was much uncertainty about the expected physiological response to fluid bolus therapy according to indication. © 2015 Elsevier Ltd. All rights reserved.
Implications for clinical practice • The administration of intravenous bolus fluid therapy is a common intervention in the care of critically ill patients that is largely not supported by sound evidence. • Findings demonstrated that 250 ml constituted a fluid bolus, albumin 4% was the fluid of choice and that the fluid should be administered as quickly as possible. However, reported fluid bolus volume varied from 100 ml to 1000 ml and there was uncertainty as to the expected physiological response following a fluid bolus. • Our findings provide evidence that hypotension is the dominant trigger for fluid bolus therapy and that nurses may overestimate the expected effects of fluid bolus therapy on key physiological variables. • To verify these findings it is now important to examine the practice and perceptions of fluid bolus therapy of intensive care nurse drawn from other intensive care units.
Introduction Intensive care patients are often prescribed maintenance intravenous (IV) fluids to prevent dehydration, treat or prevent hypovolaemia or to provide a vehicle for nutritional or pharmaceutical agents (Baid, 2010; Grocott et al., 2005). Fluid bolus therapy (FBT) is the rapid administration of a volume of IV fluid for the purposes of correcting haemodynamic instability (Vincent and Weil, 2006). Frequently, intensive care nurses administer, monitor and manage such IV fluid bolus therapy (FBT) for intensive care patients. FBT is a standard of care in the management of hypotensive, septic, oliguric and tachycardic patients (McLuckie, 2009; Molyneuz and Maitland, 2005), with FBT believed to effectively compensate for the reduction in cardiac output or venous return secondary to suspected hypovolaemia or vasodilation. On return to the intensive care unit (ICU), patients following open-heart surgery are frequently administered IV fluids for hypotension (Parke et al., 2014). Fluid overload after open-heart surgery is common and an identified marker of intra-ICU mortality and prolonged ICU length of stay (Stein et al., 2012). Of the fluids received after open-heart surgery, FBT contributes a large proportion of the positive fluid balance (Parke et al., 2014). However, the early post-operative fluid management of these patients is complex and the best way to delivery fluids is uncertain (Parke et al., 2014). Oliguria also occurs often in intensive care patients and may indicate that kidney function is endangered (Macedo et al., 2011). Severe oliguria and kidney failure requires dialysis and can lead to prolonged ICU admission and poor patient outcomes (Macedo et al., 2011; Payen et al., 2008). Intravenous FBT in the management of oliguria is thought to help preserve kidney function, yet the level of evidence to support FBT for oliguria is not strong (Payen et al., 2008). Another patient population that frequently receives FBT are those with sepsis. Almost 10% of all admissions to Australian and New Zealand ICUs are sepsis related (Kaukonen et al., 2014). Fluid resuscitation for
septic patients typically involves the rapid administration of crystalloid or colloid solutions and occurs mostly during the first 24 hours of ICU admission (Myburgh et al., 2012). At the present time, consensus opinion of the perceived benefits of intravenous FBT in clinical practice is such that the Surviving Sepsis Campaign guideline recommends 30 ml/kg as a key initial therapeutic intervention for septic critically ill patients (Dellinger et al., 2013). However, the actual impact of liberal or restrictive fluid management to critically ill septic patients remains unresolved (Bihari et al., 2013). Consequently, despite the ubiquity of the intervention, limited consensus exists regarding what exactly defines an intravenous fluid bolus (type of fluid, volume, rate of administration) or the anticipated benefits to short-term and longterm physiological and patient-centred outcomes associated with FBT (Bagshaw and Bellomo, 2007; Finfer et al., 2010; Vincent and Weil, 2006). Significantly, intensive care nurses at different times may be responsible for the initiation, administration, and ongoing management of FBT, either by protocol or by liaising with medical staff. Despite the degree of responsibility assumed by nursing staff for the delivery of FBT, little is known about the nursing practice of FBT. Accordingly, we conducted a survey of intensive care nurses to describe their self-reported attitudes and practices of intravenous FBT. Specifically, we aimed to identify the type, volume and duration of an intravenous bolus fluid. In addition, we wished to understand clinician involvement in deciding to administer a fluid bolus. Finally, we aimed to identify the common physiological triggers for, and anticipated physiological response to, FBT.
Methods Ethical approval Human research ethics committee approval (LNR/ 14/Austin/137) was obtained prospectively. The need
Please cite this article in press as: Eastwood GM, et al. Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy. Intensive Crit Care Nurs (2015), http://dx.doi.org/10.1016/j.iccn.2015.06.001
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Intravenous fluid bolus therapy for informed consent was unnecessary in this anonymous survey.
Development and pilot testing of the questionnaire We used an anonymous structured multi-choice questionnaire to survey intensive care nurses. This questionnaire was purposefully developed to complement a concurrent fluid bolus therapy questionnaire targeting medical intensive care clinicians. The questionnaire consisted of fifteen questions in three parts. The first part of the questionnaire sought information on the type, volume, duration of administration and clinician involvement in administering a fluid bolus. The second part of the questionnaire elicited information on the physiological triggers for and the anticipated physiological response to the administration of an IV fluid bolus. The third part of the questionnaire obtained basic demographic and practice-oriented details. To tailor our survey to our nursing cohort we included the fluids available in our unit and listed fluid volume in millilitres to reflect current FBT prescription practices. We pilot tested the questionnaire among seven experienced intensive care clinicians (two nursing professors, one associate nurse unit manager, two senior critical care nurses as well as two intensive care medical research fellows). Minor changes were made to reduce the number of questions, to ensure a nursing focus to the questionnaire and to increase the clarity of each question prior to the survey being conducted. Due to the small number of changes to the questionnaire no further pilot-testing was performed (Burns et al., 2008).
Target population and questionnaire administration Intensive care nurses employed in our 22-bed ICU of a major tertiary referral centre, Melbourne, Australia were eligible to participate in this study. Our ICU admits approximately 2200 patients annually including cardiac surgical patients and is the state-wide referral centre for spinal cord injuries, chronic respiratory failure and liver transplant medicine. Our target population included 220 nurses of which 45 (20%) were employed on a full-time basis. All nurses were informed of the study via an internal email and brief presentations at weekday in-service education sessions. To optimise survey completion, nurses were invited to complete either a paper-based survey or to access the survey via a web-link that was contained within the survey invitation Nurses were approached during weekday rounding by ICU research coordinators and a reminder. Nurses who expressed an interest were provided with a questionnaire and asked to deposit completed questionnaires into designated survey collection boxes located within the ICU. All responses were collected from 14th to 31st July, 2014.
Data management and analysis Anonymous questionnaire responses were collated using an online survey site (SurveyMonkey® , Palo Alto, CA, USA) to facilitate data management and analysis. All responses are expressed as a percentage (%) of the total number of responses for that question. No imputation has been made
3 Table 1 Characteristics respondents. Question
of
intensive
care
nurse
Responsesa
Your gender? (140 responses) Male 24 (17%) Female 116 (83%) Years of experience intensive care? (140 responses) Less than 5 years 37 (26.4%) 5—10 years 52 (37.1%) 11—15 years 22 (15.8%) 16—20 years 15 (10.7%) More than 20 years 14 (10%) Which of the following options best describes your intensive care qualification? (139 responses) No formal qualification 13 (9.3%) Graduate certificate 76 (54.7%) Postgraduate diploma 37 (26.6%) Other higher degree 13 (9.4%) Which of the following best describes your work pattern? (139 responses) Day shifts 24 (17.3%) Night shifts 14 (10.1%) Rotating day and night shifts 101 (73.6%) a
Responses = All responses are expressed as a % of the total number of responses for that question.
as the proportion of missing values was so low: all questions had three or less missing responses. Data collected by this questionnaire were analysed using simple procedures to calculate proportions. To examine for differences between respondents multivariable analysis was performed using SPSS statistical package V19.0 for Windows with a p value of <0.01 for statistical significance.
Findings Cohort demographics Overall, 141 (64.1%) intensive care nurses responded to the survey invitation. Of the respondents, 116 (82.8%) were female, 52 (37.1%) reported having between 5 and 10 years of critical care practice, 76 (54.7%) had a graduate certificate in intensive care and 101 (72.6%) worked a rotating ‘day and night’ shift roster (Table 1).
Choice of fluid, volume, duration of administration and decisions associated with FBT Overall, 100/140 respondents (71.4%) indicated that 4% albumin solution was the most commonly used bolus fluid, 30 (21.4%) compounded sodium lactate solution, and 9 (6.4%) 20% albumin (Table 2). 100/139 respondents (71.9%) considered a fluid bolus to be at least 250 ml and 27 (19.4%) considered a fluid bolus to be at least 500 ml, and 12 (8.6%) identified 100 ml, 200 ml or 1000 ml as being a fluid bolus (Table 2). Compared to respondents without a formal critical care qualification, graduate level respondents were more likely to select ‘Albumin 4%’ (60/76, 78% vs. 5/13, 38%)
Please cite this article in press as: Eastwood GM, et al. Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy. Intensive Crit Care Nurs (2015), http://dx.doi.org/10.1016/j.iccn.2015.06.001
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Question
Responsesa
Of the fluids listed below which do you most commonly administer as an intravenous fluid bolus? (140 responses) 1. Albumin 4% 100 (71.4%) 2. Albumin 20% 9 (6.4%) 3. 0.9% saline 1 (0.7%) 4. Plasmalyte 0 (0%) 5. Compound sodium 30 (21.4%) lactate/Hartmann’s solution Which volume of fluid do you consider to be an intravenous fluid bolus? (139 responses) 1. 100 ml 5 (3.6%) 2. 200 ml 5 (3.6%) 3. 250 ml 100 (72%) 4. 500 ml 27 (19.4%) 5. 1000 ml 2 (1.4%) 6. >1000 ml 0 (0%) Over what duration do you feel that an intravenous fluid bolus should be given? (140 responses) 1. As quickly as possible 79 (56.4%) 2. < 15 minutes 33 (23.6%) 3. 15—30 minutes 21 (15%) 4. 30—60 minutes 7 (5%) 5. >60 minutes 0 In your opinion, who is the primary clinician responsible for making the decision to give a patient a fluid bolus? (138 responses) 1. Bedside nurse 10 (7.25%) 2. Charge nurse 0 (0%) 3. ICU registrar 117 (84.8%) 4. Resident Medical Officer 10 (7.25%) (RMO) or Hospital Medical Officer (HMO) 5. ICU consultant 0 (0%) 6. Patient’s treating surgeon 1 (0.7%) or physician How often do you initiate the discussion with the intensive care doctor to give an intravenous fluid bolus? (141 responses) 1. 100% of the time 46 (36.2%) 2. Between 50 and 100% of 82 (58.1%) the time 3. <50% of the time 12 (8.5%) 4. Never 1 (0.7%) Without a written ‘existing’ order, how often do you independently decide to give an intravenous fluid bolus? (141 responses) 1. 100% of the time 4 (2.8%) 2. Between 50 and 100% of 21 (14.9%) the time 3. <50% of the time 42 (29.8%) 4. Never 74 (52.5%) ICU = intensive care unit. a Responses = all responses are expressed as a % of the total number of responses for that question.
and less likely to select ‘compound sodium lactate’ solution (12/76, 16% vs. 7/13, 54%) as their IV fluid of choice (p < 0.01). Respondents were asked to indicate the duration of time with which a fluid bolus should be administered: 79 respondents (56.4%) selected ‘as quickly as possible’, 33 (23.6%) indicated ‘less than 15 minutes’ and 21 (15%) identified ‘15—30 minutes,’ with the remaining respondents indicating ‘30—60 minutes’ (Table 2).
Clinician involvement in deciding to administer FBT One hundred and seventeen respondents (84.8%) indicated that the primary prescriber of a fluid bolus was the ‘ICU Registrar’. An equal number of respondents (10/138, 7.25%) named the ‘Bedside nurse’ and the ‘Resident Medical Officer’ as being the primary responsible clinician. Respondents were asked to indicate how often they initiated the discussion with the intensive care doctor to give an intravenous fluid bolus: 82 (58.1%) stated ‘Between 50 and 100% of the time’, 46 (32.6%) stated ‘100% of the time’, and 13 (9.2%) indicated ‘less than 50% of the time’ or ‘Never’ (Table 2). When asked if they gave a fluid bolus without a written ‘existing’ order: 74 respondents (52.5%) stated ‘Never’, 42 (29.8%) choose ‘less than 50% of the time’, 21 (14.9%) indicated ‘between 50 and 100% of the time’, and 4 (2.8%) indicated ‘100% of the time’ (Table 2).
Physiological triggers for, and anticipated physiological response to, FBT From a list of five common physiological abnormalities respondents were asked to indicate which abnormality they felt most commonly triggered a fluid bolus: 116 respondents (82.2%) selected ‘hypotension’, 10 (7.1%) chose ‘low central venous pressure (CVP)’, 5 (3.5%) identified ‘oliguria’, 3 (2.1%) indicated ‘tachycardia’, and 2 (1.4%) selected low pulmonary artery pressure. Four respondents (2.8%) selected ‘Other’ and commented that it was a combination of physiological triggers that would be used to administer a fluid bolus rather than a single physiological trigger. Respondents were then asked to indicate their anticipated physiological response in the hour following a fluid bolus for four common FBT indications: for hypotension, 59 respondents (42.4%) identified an ‘increase in mean arterial pressure (MAP) of 11—20 mmHg’ (Fig. 1); for oliguria, 25 respondents (17.9%) selected an ‘increase in urinary output
Percentage (%)
Table 2 Choice of fluid, volume, duration of administration and clinician involvement in fluid bolus therapy.
50 45 40 35 30 25 20 15 10 5 0 An increase in MAP of 0 to 10 mmHg
An increase in An increase in MAP of 11 to 20 MAP of >20 mmHg mmHg Mean arterial pressure (MAP)
Unsure
Figure 1 Anticipated physiological response to hypotension one hour after a fluid bolus (n = 291).
Please cite this article in press as: Eastwood GM, et al. Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy. Intensive Crit Care Nurs (2015), http://dx.doi.org/10.1016/j.iccn.2015.06.001
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Percentage (%)
Intravenous fluid bolus therapy
5
80
20% expecting the UO to quadruple, and 45% expecting a decrease in HR of 11—20 beats/minute. In addition, many nurses were unsure about what to expect physiologically in the hour following the administration of a fluid bolus.
60 40 20 0 An increase in An increase in An increase in urinary output of urinary output of 2 urinary output of > to 4 ml/kg/hour 0.5 to 1 4 ml/kg/hour ml/kg/hour Urinary output (UO)
Unsure
Comparison with previous studies
Percentage (%)
Figure 2 Anticipated physiological response to oligura one hour after a fluid bolus (n = 293). 60 50 40 30 20 10 0 An increase in CVP of 0 to 2 mmHg
An increase in An increase in CVP of 3 to 4 CVP of > 4 mmHg mmHg Central venous pressure (CVP)
Unsure
Figure 3 Anticipated physiological response in central venous pressure one hour after a fluid bolus (n = 288). Percentage (%)
50 40 30 20 10 0 A decrease in HR A decrease in HR A decrease in HR of 0 to 10 of 11 to 20 of > 20 beats/minute beats/minute beats/minute Heart rate (HR)
Unsure
Figure 4 Anticipated physiological response to tachycardia one hour after a fluid bolus (n = 293).
(UO) of 2—4 ml/kg/hour’ (Fig. 2); for low CVP, 71 respondents (50.1%) indicated ‘an increase in CVP of 3—4 mmHg’ (Fig. 3); and, for tachycardia, 63 respondents (45.3%) chose a ‘decrease in heart rate of 11—20 beats/minute (Fig. 4).
Discussion Summary of major findings The majority of our cohort of intensive care nurses considered a fluid bolus to be 250 ml. However, it was surprising that the size of what constitutes a bolus varied from 100 to 1000 ml (a 10-fold difference). While half of the respondents indicated that a fluid bolus should be administered as quickly as possible, other respondents accepted durations of up to 30 minutes and one hour (a fivefold variability) still constituted FBT. While medical staff were primarily responsible for the administration of FBT, it was common for nursing staff to initiate the discussion or, in the absence of a written order, to independently administer FBT. Hypotension was identified as the commonest physiological FBT trigger. A significant proportion of nurses anticipated unrealistic physiological responses to a fluid bolus: with >40% of respondents expecting an increase in MAP of between 11 and 20 mmHg,
To the best of our knowledge, this is the first survey to describe intensive care nurses’ self-reported practice of FBT. However, using recent prospective observational data and drawing from the critical care fluid resuscitation literature it is possible to relate our findings to current practice. A recent multi-centre, prospective observational study described the current practice of fluid administration in post-operative cardiac surgical patients (Parke et al., 2014). Of the 1226 fluid boluses reported, 64.7% were given for hypotension, and 64% were crystalloid, with an average volume of 561 ml; average colloid boluses were smaller at 387 ml. This is in contrast to our finding that ICU nurses feel most comfortable using 4% Albumin; colloid only accounted for 14.2% of episodes in the cardiac cohort. In the cardiac surgery study the ‘bedside nurse’ was the primary decision maker in 40% of episodes compared to 7.25% in our cohort. Some of the disparities are likely to reflect cost and availability of colloids, the patient characteristics, and the presence of ‘standing orders’ covering the administration of up to 3 L of fluid for volume resuscitation at the discretion of the bedside nurse. The best approach to FBT for critically ill patients remains controversial; however emerging evidence is helping to identify current practice, triggers for FBT (Finfer et al., 2010) and patient outcomes associated with fluid resuscitation in intensive care (Maitland et al., 2011; Myburgh et al., 2012). For example, a cross-sectional study in 2010 involving 391 ICUs across 25 countries described the types of fluids administered during resuscitation episodes. Finfer et al. (2010), examined 4488 episodes of FBT involving 1955 patients during the 24-hour study period. Perceived signs of impaired perfusion (1526/3419, 44.6%) and the desire to correct abnormal vital signs (1189/3419, 24.8%) were the main indications for FBT, with colloids being given more frequently than crystalloids; however, the choice of fluid varied markedly between countries. The identification of albumin as the primary fluid of choice at our centre was unsurprising for two main reasons. Firstly, the study hospital is the state referral-centre for liver failure patients where the administration of 4% or 20% albumin is the preferred intravenous fluid for patients with cirrhosis and spontaneous bacterial peritonitis (Sort et al., 1999). Secondly, since 2009 it has been our unit practice to implement a chloride-restrictive IV fluid strategy (Yonus et al., 2012). Application of this approach has seen a dramatic reduction in the use of chloride-rich fluids like saline (Yonus et al., 2012). As such, the responses provided in our survey are likely to reflect local ecological conditions associated with the availability of fluids and trends in fluid prescription practices tailored to our patient population. In addition, our finding that critical care qualified nurses compared to those without a formal qualification were more likely to select Albumin 4% may be reflective of clinical knowledge and the frequency of use within our ICU.
Please cite this article in press as: Eastwood GM, et al. Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy. Intensive Crit Care Nurs (2015), http://dx.doi.org/10.1016/j.iccn.2015.06.001
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A key determinant of FBT effectiveness is the ability to correct haemodynamic instability and perceived impaired tissue perfusion, and the duration of this physiological response. In 2013, Bihari, Prakash and Bersten reported the findings of a single centre prospective observational study undertaken to estimate the efficacy of FBT in 50 patients with severe sepsis and septic shock. For these patients low blood pressure (76%) and increased vasopressor requirement (60%) were the most common FBT indications. For the first day the median fluid bolus volume was 750 ml (IQR 500—1750 ml). However, by one hour following FBT the MAP had only increased by 2 mmHg; HR was unchanged; CVP had risen by 2 mmHg; and UO was unaffected. Such findings therefore indicate that the expectations of the physiological effects of FBT by our nursing cohort are dissociated from prospective observational data.
Clinical implications Our study is the first to describe what ICU nurses define as FBT, what physiological abnormalities they report trigger such FBT and what kind of physiological outcomes they expect from its use. Its findings highlight that there are disparate views of what constitutes FBT with up to 10fold variability in volume and fivefold variability in speed of delivery. They also provide evidence that hypotension is the dominant trigger for FBT and, finally, they suggest that nurses may overestimate the expected effects of FBT on key physiological variables in comparison with effects reported in the literature (Bihari et al., 2013).
Strengths and limitations To our knowledge, this is the largest sample of Australian intensive care nurses surveyed in relation to self-reported intravenous FBT practices reported. The findings of this study have helped to inform our understanding of this important aspect of intensive care practice. However, our responses are limited by the single centre design. Second, responses were self-reported data and, as such, may not reflect actual practice. Thirdly, in Australia, 4% and 20% albumin is freely available, being provided by the Red Cross as a by-product of blood product manufacture. It is therefore unsurprising that albumin is frequently used in our, and other Australian centres. In addition, the study hospital is the state referral-centre for liver failure patients where the administration of 4% or 20% albumin is the preferred intravenous fluid for patients with cirrhosis and spontaneous bacterial peritonitis (Sort et al., 1999). As such, the responses provided in our survey are likely to reflect local ecological conditions associated with the availability of fluids and trends in fluid prescription practices tailored to our patient population. Finally, the questions about anticipated physiological responses to administering an intravenous FBT may not have provided enough information on which to make a definitive clinical judgement. Importantly, our survey did not explore the individual patient contexts associated with decisions related to FBT. In response, we recognise that FBT and effective management of patients’ haemodynamic instabilities, irrespective of cause, remains fundamental to optimising patient outcomes. Therefore, it is now important
to assess the external validity of our findings by examining the practice and perceptions of FBT of intensive care nurses drawn from other ICUs.
Conclusion In a study of a cohort of ICU nurses the most common definition of FBT involved 250 ml of 4% albumin given as quickly as possible. However, there was substantial variability in the definition of FBT with volumes being cited varying from 100 to 1000 ml. We also found great uncertainty about the anticipated physiological response to a fluid bolus and a general overestimation of the physiological effects of FBT. Our study provides initial data on a major area of nursing practice and justifies more extensive investigations.
Authors’ contributions Adj. A/Prof Eastwood participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Ms Peck participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Ms Young participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Ms Paton participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Dr Glassford participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Dr Zhang participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Dr Zhu participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Dr Aiko Tanaka participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Professor Rinaldo Bellomo participated in the design, conduct and analysis of the study and that I have seen and approved the final version.
Funding The authors have no sources of funding to declare.
Conflict of interest The authors have no conflict of interest to declare.
Acknowledgements We wish to thank the intensive care nurses who kindly completed our survey.
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Intravenous fluid bolus therapy Bihari S, Prakash, Bersten AD. Post resuscitation fluid boluses in severe sepsis or septic shock: prevalence and efficacy (PRICE study). Shock 2013;40(1):28—34. Burns KEA, Duffett M, Kho ME, et al. A guide for the design and conduct of self-administered surveys of clinicians. Can Med Assoc J 2008;179(3):245—52. Dellinger RP, Levy MM, Rhodes A, et al. Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2012. Crit Care Med 2013;41(2):580—637. Finfer S, Liu B, Taylor C, et al. Resuscitation fluid use in critically ill adults: an international cross-sectional study in 391 intensive care units. Crit Care 2010;14(5):R185. Grocott MPW, Mythen MG, Gan TJ. Perioperative fluid management and clinical outcomes in adults. Anesth Analg 2005;100(4):1093—106. Kaukonen K-M, Bailey M, Suzuki S, Pilcher D, Bellomo R. Mortality related to severe sepsis and septic shock in critically ill patients in Australia and New Zealand. JAMA 2014;311(13):1308—16. McLuckie A. Shock — an overview. In: Bersten AD, editor. Oh’s intensive care manual. 6th ed. Philadelphia: Elsevier Limited; 2009. p. 97—104. Macedo E, Malhotra R, Bouchardd J, Wynn SK, Mehta RL. Oliguria is an early predictor of higher mortality in critically ill patients. Kidney Int 2011;80(7):760—7. Maitland K, Kiguli S, Opoka RO, et al. Mortality after fluid bolus in African children with severe infection. N Engl J Med 2011;364(26):2483—95.
7 Molyneuz EM, Maitland K. Intravenous fluid — getting the balance right. N Engl J Med 2005;353(9):941—4. Myburgh JA, Finfer S, Bellomo R, et al. Hydroxyethyl starch or saline for fluid resuscitation in intensive care. N Engl J Med 2012;367(20):1901—11. Parke RL, McGuinness SP, Gilder E, McCarthy LW. Intravenous fluid use after cardiac surgery: a multicentre, prospective, observational study. Crit Care Resusc 2014;16(3):164—9. Payen D, de Pont AC, Sakr Y, et al. , Sepsis Occurrence in Acutely Ill Patients (SOAP) Investigators. A positive fluid balance is associated with worse outcome in patients with acute renal failure. Crit Care 2008;12(3):R74. Sort P, Navasa M, Arroyo V, et al. Effect of intravenous albumin on renal impairment and mortality in patients with cirrhosis and spontaneous bacterial peritonitis. N Engl J Med 1999;341(6):403—9. Stein A, de Souza LV, Belettini CR, et al. Fluid overload and changes in serum creatinine after cardiac surgery: predictors of mortality and longer intensive care stay. A prospective cohort study. Crit Care 2012;16(3):R99. Vincent JL, Weil MH. Fluid challenge revisited. Crit Care Med 2006;34(5):1333—7. Yonus NM, Bellomo R, Hegarty C, Story D, Ho L, Bailey M. Association between a chloride-liberal vs chloride-restrictive intravenous fluid administration strategy and kidney injury in critically ill adults. JAMA 2012;308(15):1566—72.
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Intensive and Critical Care Nursing (2015) xxx, xxx—xxx
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/iccn
Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy Glenn M. Eastwood a,∗, Leah Peck a, Helen Young a, Emily Paton a, Neil J. Glassford a, Ling Zhang b, Guijun Zhu c, Aiko Tanaka a, Rinaldo Bellomo a a
Department of Intensive Care, Austin Hospital, Victoria, Australia Department of Nephrology, West China Medical School, West China Hospital, Sichuan, China c Department of Intensive Care, The Fourth Hospital of Hebei Austin Hospital, Hebei, China b
Accepted 1 June 2015
KEYWORDS Acute care nursing; Bolus fluid therapy; Fluid resuscitation; Decision-making; Intravenous fluid
Summary Objective: To describe self-reported practice of fluid bolus therapy by intensive care nurses. Research methodology: Multi-choice questionnaire of intensive care nurses conducted in July, 2014. Setting: Major university tertiary referral centre. Findings: 141 (64%) intensive care nurses responded. The majority of respondents identified 4% albumin as the commonest fluid bolus type and stated a fluid bolus was 250 ml; however fluid bolus volume varied from 100 ml to 1000 ml. Hypotension was identified as the primary physiological trigger for a fluid bolus. In the hour following a fluid bolus for hypotension almost half of respondents expected an ‘increase in mean arterial pressure of 0—10 mmHg’; for oliguria, >60% expected an ‘increase in urinary output of ‘0.5—1 ml/kg/hour’; for low CVP, 50% expected ‘an increase in CVP of 3—4 mmHg’; and, for tachycardia, 45% expected a ‘decrease in heart rate of 11—20 beats/minute’. Finally, 7—10% of respondents were ‘unsure’ about the physiological response to a fluid bolus.
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Corresponding author. Tel.: +61 3 9496 4835; fax: +61 3 9496 3932. E-mail addresses: [email protected] (G.M. Eastwood), [email protected] (L. Peck), [email protected] (H. Young), [email protected] (E. Paton), [email protected] (N.J. Glassford), [email protected] (L. Zhang), [email protected] (G. Zhu), [email protected] (A. Tanaka), [email protected] (R. Bellomo). http://dx.doi.org/10.1016/j.iccn.2015.06.001 0964-3397/© 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Eastwood GM, et al. Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy. Intensive Crit Care Nurs (2015), http://dx.doi.org/10.1016/j.iccn.2015.06.001
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G.M. Eastwood et al. Conclusion: Most respondents identified fluid bolus therapy to be at least 250 ml of 4% albumin given as quickly as possible; however, volumes from 100 to 1000 ml were also accepted. There was much uncertainty about the expected physiological response to fluid bolus therapy according to indication. © 2015 Elsevier Ltd. All rights reserved.
Implications for clinical practice • The administration of intravenous bolus fluid therapy is a common intervention in the care of critically ill patients that is largely not supported by sound evidence. • Findings demonstrated that 250 ml constituted a fluid bolus, albumin 4% was the fluid of choice and that the fluid should be administered as quickly as possible. However, reported fluid bolus volume varied from 100 ml to 1000 ml and there was uncertainty as to the expected physiological response following a fluid bolus. • Our findings provide evidence that hypotension is the dominant trigger for fluid bolus therapy and that nurses may overestimate the expected effects of fluid bolus therapy on key physiological variables. • To verify these findings it is now important to examine the practice and perceptions of fluid bolus therapy of intensive care nurse drawn from other intensive care units.
Introduction Intensive care patients are often prescribed maintenance intravenous (IV) fluids to prevent dehydration, treat or prevent hypovolaemia or to provide a vehicle for nutritional or pharmaceutical agents (Baid, 2010; Grocott et al., 2005). Fluid bolus therapy (FBT) is the rapid administration of a volume of IV fluid for the purposes of correcting haemodynamic instability (Vincent and Weil, 2006). Frequently, intensive care nurses administer, monitor and manage such IV fluid bolus therapy (FBT) for intensive care patients. FBT is a standard of care in the management of hypotensive, septic, oliguric and tachycardic patients (McLuckie, 2009; Molyneuz and Maitland, 2005), with FBT believed to effectively compensate for the reduction in cardiac output or venous return secondary to suspected hypovolaemia or vasodilation. On return to the intensive care unit (ICU), patients following open-heart surgery are frequently administered IV fluids for hypotension (Parke et al., 2014). Fluid overload after open-heart surgery is common and an identified marker of intra-ICU mortality and prolonged ICU length of stay (Stein et al., 2012). Of the fluids received after open-heart surgery, FBT contributes a large proportion of the positive fluid balance (Parke et al., 2014). However, the early post-operative fluid management of these patients is complex and the best way to delivery fluids is uncertain (Parke et al., 2014). Oliguria also occurs often in intensive care patients and may indicate that kidney function is endangered (Macedo et al., 2011). Severe oliguria and kidney failure requires dialysis and can lead to prolonged ICU admission and poor patient outcomes (Macedo et al., 2011; Payen et al., 2008). Intravenous FBT in the management of oliguria is thought to help preserve kidney function, yet the level of evidence to support FBT for oliguria is not strong (Payen et al., 2008). Another patient population that frequently receives FBT are those with sepsis. Almost 10% of all admissions to Australian and New Zealand ICUs are sepsis related (Kaukonen et al., 2014). Fluid resuscitation for
septic patients typically involves the rapid administration of crystalloid or colloid solutions and occurs mostly during the first 24 hours of ICU admission (Myburgh et al., 2012). At the present time, consensus opinion of the perceived benefits of intravenous FBT in clinical practice is such that the Surviving Sepsis Campaign guideline recommends 30 ml/kg as a key initial therapeutic intervention for septic critically ill patients (Dellinger et al., 2013). However, the actual impact of liberal or restrictive fluid management to critically ill septic patients remains unresolved (Bihari et al., 2013). Consequently, despite the ubiquity of the intervention, limited consensus exists regarding what exactly defines an intravenous fluid bolus (type of fluid, volume, rate of administration) or the anticipated benefits to short-term and longterm physiological and patient-centred outcomes associated with FBT (Bagshaw and Bellomo, 2007; Finfer et al., 2010; Vincent and Weil, 2006). Significantly, intensive care nurses at different times may be responsible for the initiation, administration, and ongoing management of FBT, either by protocol or by liaising with medical staff. Despite the degree of responsibility assumed by nursing staff for the delivery of FBT, little is known about the nursing practice of FBT. Accordingly, we conducted a survey of intensive care nurses to describe their self-reported attitudes and practices of intravenous FBT. Specifically, we aimed to identify the type, volume and duration of an intravenous bolus fluid. In addition, we wished to understand clinician involvement in deciding to administer a fluid bolus. Finally, we aimed to identify the common physiological triggers for, and anticipated physiological response to, FBT.
Methods Ethical approval Human research ethics committee approval (LNR/ 14/Austin/137) was obtained prospectively. The need
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Intravenous fluid bolus therapy for informed consent was unnecessary in this anonymous survey.
Development and pilot testing of the questionnaire We used an anonymous structured multi-choice questionnaire to survey intensive care nurses. This questionnaire was purposefully developed to complement a concurrent fluid bolus therapy questionnaire targeting medical intensive care clinicians. The questionnaire consisted of fifteen questions in three parts. The first part of the questionnaire sought information on the type, volume, duration of administration and clinician involvement in administering a fluid bolus. The second part of the questionnaire elicited information on the physiological triggers for and the anticipated physiological response to the administration of an IV fluid bolus. The third part of the questionnaire obtained basic demographic and practice-oriented details. To tailor our survey to our nursing cohort we included the fluids available in our unit and listed fluid volume in millilitres to reflect current FBT prescription practices. We pilot tested the questionnaire among seven experienced intensive care clinicians (two nursing professors, one associate nurse unit manager, two senior critical care nurses as well as two intensive care medical research fellows). Minor changes were made to reduce the number of questions, to ensure a nursing focus to the questionnaire and to increase the clarity of each question prior to the survey being conducted. Due to the small number of changes to the questionnaire no further pilot-testing was performed (Burns et al., 2008).
Target population and questionnaire administration Intensive care nurses employed in our 22-bed ICU of a major tertiary referral centre, Melbourne, Australia were eligible to participate in this study. Our ICU admits approximately 2200 patients annually including cardiac surgical patients and is the state-wide referral centre for spinal cord injuries, chronic respiratory failure and liver transplant medicine. Our target population included 220 nurses of which 45 (20%) were employed on a full-time basis. All nurses were informed of the study via an internal email and brief presentations at weekday in-service education sessions. To optimise survey completion, nurses were invited to complete either a paper-based survey or to access the survey via a web-link that was contained within the survey invitation Nurses were approached during weekday rounding by ICU research coordinators and a reminder. Nurses who expressed an interest were provided with a questionnaire and asked to deposit completed questionnaires into designated survey collection boxes located within the ICU. All responses were collected from 14th to 31st July, 2014.
Data management and analysis Anonymous questionnaire responses were collated using an online survey site (SurveyMonkey® , Palo Alto, CA, USA) to facilitate data management and analysis. All responses are expressed as a percentage (%) of the total number of responses for that question. No imputation has been made
3 Table 1 Characteristics respondents. Question
of
intensive
care
nurse
Responsesa
Your gender? (140 responses) Male 24 (17%) Female 116 (83%) Years of experience intensive care? (140 responses) Less than 5 years 37 (26.4%) 5—10 years 52 (37.1%) 11—15 years 22 (15.8%) 16—20 years 15 (10.7%) More than 20 years 14 (10%) Which of the following options best describes your intensive care qualification? (139 responses) No formal qualification 13 (9.3%) Graduate certificate 76 (54.7%) Postgraduate diploma 37 (26.6%) Other higher degree 13 (9.4%) Which of the following best describes your work pattern? (139 responses) Day shifts 24 (17.3%) Night shifts 14 (10.1%) Rotating day and night shifts 101 (73.6%) a
Responses = All responses are expressed as a % of the total number of responses for that question.
as the proportion of missing values was so low: all questions had three or less missing responses. Data collected by this questionnaire were analysed using simple procedures to calculate proportions. To examine for differences between respondents multivariable analysis was performed using SPSS statistical package V19.0 for Windows with a p value of <0.01 for statistical significance.
Findings Cohort demographics Overall, 141 (64.1%) intensive care nurses responded to the survey invitation. Of the respondents, 116 (82.8%) were female, 52 (37.1%) reported having between 5 and 10 years of critical care practice, 76 (54.7%) had a graduate certificate in intensive care and 101 (72.6%) worked a rotating ‘day and night’ shift roster (Table 1).
Choice of fluid, volume, duration of administration and decisions associated with FBT Overall, 100/140 respondents (71.4%) indicated that 4% albumin solution was the most commonly used bolus fluid, 30 (21.4%) compounded sodium lactate solution, and 9 (6.4%) 20% albumin (Table 2). 100/139 respondents (71.9%) considered a fluid bolus to be at least 250 ml and 27 (19.4%) considered a fluid bolus to be at least 500 ml, and 12 (8.6%) identified 100 ml, 200 ml or 1000 ml as being a fluid bolus (Table 2). Compared to respondents without a formal critical care qualification, graduate level respondents were more likely to select ‘Albumin 4%’ (60/76, 78% vs. 5/13, 38%)
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Question
Responsesa
Of the fluids listed below which do you most commonly administer as an intravenous fluid bolus? (140 responses) 1. Albumin 4% 100 (71.4%) 2. Albumin 20% 9 (6.4%) 3. 0.9% saline 1 (0.7%) 4. Plasmalyte 0 (0%) 5. Compound sodium 30 (21.4%) lactate/Hartmann’s solution Which volume of fluid do you consider to be an intravenous fluid bolus? (139 responses) 1. 100 ml 5 (3.6%) 2. 200 ml 5 (3.6%) 3. 250 ml 100 (72%) 4. 500 ml 27 (19.4%) 5. 1000 ml 2 (1.4%) 6. >1000 ml 0 (0%) Over what duration do you feel that an intravenous fluid bolus should be given? (140 responses) 1. As quickly as possible 79 (56.4%) 2. < 15 minutes 33 (23.6%) 3. 15—30 minutes 21 (15%) 4. 30—60 minutes 7 (5%) 5. >60 minutes 0 In your opinion, who is the primary clinician responsible for making the decision to give a patient a fluid bolus? (138 responses) 1. Bedside nurse 10 (7.25%) 2. Charge nurse 0 (0%) 3. ICU registrar 117 (84.8%) 4. Resident Medical Officer 10 (7.25%) (RMO) or Hospital Medical Officer (HMO) 5. ICU consultant 0 (0%) 6. Patient’s treating surgeon 1 (0.7%) or physician How often do you initiate the discussion with the intensive care doctor to give an intravenous fluid bolus? (141 responses) 1. 100% of the time 46 (36.2%) 2. Between 50 and 100% of 82 (58.1%) the time 3. <50% of the time 12 (8.5%) 4. Never 1 (0.7%) Without a written ‘existing’ order, how often do you independently decide to give an intravenous fluid bolus? (141 responses) 1. 100% of the time 4 (2.8%) 2. Between 50 and 100% of 21 (14.9%) the time 3. <50% of the time 42 (29.8%) 4. Never 74 (52.5%) ICU = intensive care unit. a Responses = all responses are expressed as a % of the total number of responses for that question.
and less likely to select ‘compound sodium lactate’ solution (12/76, 16% vs. 7/13, 54%) as their IV fluid of choice (p < 0.01). Respondents were asked to indicate the duration of time with which a fluid bolus should be administered: 79 respondents (56.4%) selected ‘as quickly as possible’, 33 (23.6%) indicated ‘less than 15 minutes’ and 21 (15%) identified ‘15—30 minutes,’ with the remaining respondents indicating ‘30—60 minutes’ (Table 2).
Clinician involvement in deciding to administer FBT One hundred and seventeen respondents (84.8%) indicated that the primary prescriber of a fluid bolus was the ‘ICU Registrar’. An equal number of respondents (10/138, 7.25%) named the ‘Bedside nurse’ and the ‘Resident Medical Officer’ as being the primary responsible clinician. Respondents were asked to indicate how often they initiated the discussion with the intensive care doctor to give an intravenous fluid bolus: 82 (58.1%) stated ‘Between 50 and 100% of the time’, 46 (32.6%) stated ‘100% of the time’, and 13 (9.2%) indicated ‘less than 50% of the time’ or ‘Never’ (Table 2). When asked if they gave a fluid bolus without a written ‘existing’ order: 74 respondents (52.5%) stated ‘Never’, 42 (29.8%) choose ‘less than 50% of the time’, 21 (14.9%) indicated ‘between 50 and 100% of the time’, and 4 (2.8%) indicated ‘100% of the time’ (Table 2).
Physiological triggers for, and anticipated physiological response to, FBT From a list of five common physiological abnormalities respondents were asked to indicate which abnormality they felt most commonly triggered a fluid bolus: 116 respondents (82.2%) selected ‘hypotension’, 10 (7.1%) chose ‘low central venous pressure (CVP)’, 5 (3.5%) identified ‘oliguria’, 3 (2.1%) indicated ‘tachycardia’, and 2 (1.4%) selected low pulmonary artery pressure. Four respondents (2.8%) selected ‘Other’ and commented that it was a combination of physiological triggers that would be used to administer a fluid bolus rather than a single physiological trigger. Respondents were then asked to indicate their anticipated physiological response in the hour following a fluid bolus for four common FBT indications: for hypotension, 59 respondents (42.4%) identified an ‘increase in mean arterial pressure (MAP) of 11—20 mmHg’ (Fig. 1); for oliguria, 25 respondents (17.9%) selected an ‘increase in urinary output
Percentage (%)
Table 2 Choice of fluid, volume, duration of administration and clinician involvement in fluid bolus therapy.
50 45 40 35 30 25 20 15 10 5 0 An increase in MAP of 0 to 10 mmHg
An increase in An increase in MAP of 11 to 20 MAP of >20 mmHg mmHg Mean arterial pressure (MAP)
Unsure
Figure 1 Anticipated physiological response to hypotension one hour after a fluid bolus (n = 291).
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Percentage (%)
Intravenous fluid bolus therapy
5
80
20% expecting the UO to quadruple, and 45% expecting a decrease in HR of 11—20 beats/minute. In addition, many nurses were unsure about what to expect physiologically in the hour following the administration of a fluid bolus.
60 40 20 0 An increase in An increase in An increase in urinary output of urinary output of 2 urinary output of > to 4 ml/kg/hour 0.5 to 1 4 ml/kg/hour ml/kg/hour Urinary output (UO)
Unsure
Comparison with previous studies
Percentage (%)
Figure 2 Anticipated physiological response to oligura one hour after a fluid bolus (n = 293). 60 50 40 30 20 10 0 An increase in CVP of 0 to 2 mmHg
An increase in An increase in CVP of 3 to 4 CVP of > 4 mmHg mmHg Central venous pressure (CVP)
Unsure
Figure 3 Anticipated physiological response in central venous pressure one hour after a fluid bolus (n = 288). Percentage (%)
50 40 30 20 10 0 A decrease in HR A decrease in HR A decrease in HR of 0 to 10 of 11 to 20 of > 20 beats/minute beats/minute beats/minute Heart rate (HR)
Unsure
Figure 4 Anticipated physiological response to tachycardia one hour after a fluid bolus (n = 293).
(UO) of 2—4 ml/kg/hour’ (Fig. 2); for low CVP, 71 respondents (50.1%) indicated ‘an increase in CVP of 3—4 mmHg’ (Fig. 3); and, for tachycardia, 63 respondents (45.3%) chose a ‘decrease in heart rate of 11—20 beats/minute (Fig. 4).
Discussion Summary of major findings The majority of our cohort of intensive care nurses considered a fluid bolus to be 250 ml. However, it was surprising that the size of what constitutes a bolus varied from 100 to 1000 ml (a 10-fold difference). While half of the respondents indicated that a fluid bolus should be administered as quickly as possible, other respondents accepted durations of up to 30 minutes and one hour (a fivefold variability) still constituted FBT. While medical staff were primarily responsible for the administration of FBT, it was common for nursing staff to initiate the discussion or, in the absence of a written order, to independently administer FBT. Hypotension was identified as the commonest physiological FBT trigger. A significant proportion of nurses anticipated unrealistic physiological responses to a fluid bolus: with >40% of respondents expecting an increase in MAP of between 11 and 20 mmHg,
To the best of our knowledge, this is the first survey to describe intensive care nurses’ self-reported practice of FBT. However, using recent prospective observational data and drawing from the critical care fluid resuscitation literature it is possible to relate our findings to current practice. A recent multi-centre, prospective observational study described the current practice of fluid administration in post-operative cardiac surgical patients (Parke et al., 2014). Of the 1226 fluid boluses reported, 64.7% were given for hypotension, and 64% were crystalloid, with an average volume of 561 ml; average colloid boluses were smaller at 387 ml. This is in contrast to our finding that ICU nurses feel most comfortable using 4% Albumin; colloid only accounted for 14.2% of episodes in the cardiac cohort. In the cardiac surgery study the ‘bedside nurse’ was the primary decision maker in 40% of episodes compared to 7.25% in our cohort. Some of the disparities are likely to reflect cost and availability of colloids, the patient characteristics, and the presence of ‘standing orders’ covering the administration of up to 3 L of fluid for volume resuscitation at the discretion of the bedside nurse. The best approach to FBT for critically ill patients remains controversial; however emerging evidence is helping to identify current practice, triggers for FBT (Finfer et al., 2010) and patient outcomes associated with fluid resuscitation in intensive care (Maitland et al., 2011; Myburgh et al., 2012). For example, a cross-sectional study in 2010 involving 391 ICUs across 25 countries described the types of fluids administered during resuscitation episodes. Finfer et al. (2010), examined 4488 episodes of FBT involving 1955 patients during the 24-hour study period. Perceived signs of impaired perfusion (1526/3419, 44.6%) and the desire to correct abnormal vital signs (1189/3419, 24.8%) were the main indications for FBT, with colloids being given more frequently than crystalloids; however, the choice of fluid varied markedly between countries. The identification of albumin as the primary fluid of choice at our centre was unsurprising for two main reasons. Firstly, the study hospital is the state referral-centre for liver failure patients where the administration of 4% or 20% albumin is the preferred intravenous fluid for patients with cirrhosis and spontaneous bacterial peritonitis (Sort et al., 1999). Secondly, since 2009 it has been our unit practice to implement a chloride-restrictive IV fluid strategy (Yonus et al., 2012). Application of this approach has seen a dramatic reduction in the use of chloride-rich fluids like saline (Yonus et al., 2012). As such, the responses provided in our survey are likely to reflect local ecological conditions associated with the availability of fluids and trends in fluid prescription practices tailored to our patient population. In addition, our finding that critical care qualified nurses compared to those without a formal qualification were more likely to select Albumin 4% may be reflective of clinical knowledge and the frequency of use within our ICU.
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A key determinant of FBT effectiveness is the ability to correct haemodynamic instability and perceived impaired tissue perfusion, and the duration of this physiological response. In 2013, Bihari, Prakash and Bersten reported the findings of a single centre prospective observational study undertaken to estimate the efficacy of FBT in 50 patients with severe sepsis and septic shock. For these patients low blood pressure (76%) and increased vasopressor requirement (60%) were the most common FBT indications. For the first day the median fluid bolus volume was 750 ml (IQR 500—1750 ml). However, by one hour following FBT the MAP had only increased by 2 mmHg; HR was unchanged; CVP had risen by 2 mmHg; and UO was unaffected. Such findings therefore indicate that the expectations of the physiological effects of FBT by our nursing cohort are dissociated from prospective observational data.
Clinical implications Our study is the first to describe what ICU nurses define as FBT, what physiological abnormalities they report trigger such FBT and what kind of physiological outcomes they expect from its use. Its findings highlight that there are disparate views of what constitutes FBT with up to 10fold variability in volume and fivefold variability in speed of delivery. They also provide evidence that hypotension is the dominant trigger for FBT and, finally, they suggest that nurses may overestimate the expected effects of FBT on key physiological variables in comparison with effects reported in the literature (Bihari et al., 2013).
Strengths and limitations To our knowledge, this is the largest sample of Australian intensive care nurses surveyed in relation to self-reported intravenous FBT practices reported. The findings of this study have helped to inform our understanding of this important aspect of intensive care practice. However, our responses are limited by the single centre design. Second, responses were self-reported data and, as such, may not reflect actual practice. Thirdly, in Australia, 4% and 20% albumin is freely available, being provided by the Red Cross as a by-product of blood product manufacture. It is therefore unsurprising that albumin is frequently used in our, and other Australian centres. In addition, the study hospital is the state referral-centre for liver failure patients where the administration of 4% or 20% albumin is the preferred intravenous fluid for patients with cirrhosis and spontaneous bacterial peritonitis (Sort et al., 1999). As such, the responses provided in our survey are likely to reflect local ecological conditions associated with the availability of fluids and trends in fluid prescription practices tailored to our patient population. Finally, the questions about anticipated physiological responses to administering an intravenous FBT may not have provided enough information on which to make a definitive clinical judgement. Importantly, our survey did not explore the individual patient contexts associated with decisions related to FBT. In response, we recognise that FBT and effective management of patients’ haemodynamic instabilities, irrespective of cause, remains fundamental to optimising patient outcomes. Therefore, it is now important
to assess the external validity of our findings by examining the practice and perceptions of FBT of intensive care nurses drawn from other ICUs.
Conclusion In a study of a cohort of ICU nurses the most common definition of FBT involved 250 ml of 4% albumin given as quickly as possible. However, there was substantial variability in the definition of FBT with volumes being cited varying from 100 to 1000 ml. We also found great uncertainty about the anticipated physiological response to a fluid bolus and a general overestimation of the physiological effects of FBT. Our study provides initial data on a major area of nursing practice and justifies more extensive investigations.
Authors’ contributions Adj. A/Prof Eastwood participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Ms Peck participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Ms Young participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Ms Paton participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Dr Glassford participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Dr Zhang participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Dr Zhu participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Dr Aiko Tanaka participated in the design, conduct and analysis of the study and that I have seen and approved the final version. Professor Rinaldo Bellomo participated in the design, conduct and analysis of the study and that I have seen and approved the final version.
Funding The authors have no sources of funding to declare.
Conflict of interest The authors have no conflict of interest to declare.
Acknowledgements We wish to thank the intensive care nurses who kindly completed our survey.
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Please cite this article in press as: Eastwood GM, et al. Intensive care nurses’ self-reported practice of intravenous fluid bolus therapy. Intensive Crit Care Nurs (2015), http://dx.doi.org/10.1016/j.iccn.2015.06.001