Intradialytic Hypotension Prevention and ...

Copyright 2015 American Nephrology Nurses’ Association (ANNA) All rights reserved. No part of this document may be reproduced or transmitted in any form without the written permission of the American Nephrology Nurses' Association.

Intradialytic Hypotension Prevention and Management Knowledge and Practices: Results from a Survey of Australian and New Zealand Nephrology Nurses

Continuing Nursing Education

Wendi Bradshaw Cherene Ockerby Paul N. Bennett he most frequent serious side effect of hemodialysis is intradialytic hypotension (IDH), which is estimated to occur in 15% to 30% of all hemodialysis treatments (Henrich, 2008; Thijssen, Kappel, & Kotanko, 2013). A person undergoing hemodialysis frequently requires the removal of greater than 2 liters of fluid in a single session (Agarwal, 2012). If vascular refill does not keep pace with fluid removal, then IDH can occur (Daugirdas, 2001). Despite the high incidence of IDH, there is a paucity of published literature discussing nursing practices to prevent, recognize, and treat IDH. Several studies have confirmed that hypoperfusion through the hemodialysis procedure itself has long-term deleterious effects that are compounded with repeated episodes of hypotension (Davenport, 2013; Eldehni & McIntyre, 2012). These effects are in addition to the danger of the hypoten-

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Wendi Bradshaw, MN, RN, is a Clinical Nurse Specialist, Monash Health, Melbourne, Victoria, Australia. She may be contacted directly via email at [email protected] Cherene Ockerby, BA (Hons), is a Research Assistant, Monash Health, Melbourne, and the Centre for Nursing Research, School of Nursing and Midwifery, Deakin University, Clayton, Victoria, Australia. Paul N. Bennett, PhD, MHSM, GCSc (App Stats), RN (Renal), is Professor and Chair, Translational Nursing, Western Health, Melbourne, Victoria, Australia. Statement of Disclosure: The authors reported no actual or potential conflict of interest in relation to this continuing nursing education activity. Note: Additional statements of disclosure and instructions for CNE evaluation can be found on page 167.

Nephrology Nursing Journal

Copyright 2015 American Nephrology Nurses’ Association Bradshaw, W., Ockerby, C., & Bennett, P.N. (2015). Intradialytic hypotension prevention and management knowledge and practices: Results from a survey of Australian and New Zealand nephrology nurses. Nephrology Nursing Journal, 42(2), 155-166. Intradialytic hypotension (IDH) remains the most frequent serious side effect of hemodialysis, increasing morbidity in patients on hemodialysis. Nephrology nurses have a critical role in the prevention and management of IDH. The aim of this study was to investigate nephrology nurse knowledge and practice habits in the prevention and management of IDH. This was an explorative cross-sectional design, web-based survey of Australian and New Zealand nephrology nurses (n = 173). IDH definitions, blood pressure interpretation, and IDH interventions were inconsistent and not always evidencebased. Demographic characteristics had little impact on the variation in responses. A universal definition for IDH may improve early recognition of the problem. Formal guidelines in considering individualized interventional strategies for asymptomatic episodes prior symptomatic IDH occurrence may improve outcomes for patients on hemodialysis. Key Words: Blood pressure, hemodialysis, intradialytic hypotension, nursing, nephrology.

Goal To provide an overview of nephrology nurse knowledge and practice habits in the prevention and management and treatment of intradialytic hypotension (IDH) as reported by nephrology nurses surveyed in Australia and New Zealand. Objectives

1. 2. 3.

Identify the varying definitions of intradialytic hypotension (IDH). Discuss the importance of nephrology nurses’ knowledge of IDH identification. Explain possible prevention and management strategies of IDH as reflected by outcomes of this study.

This offering for 1.4 contact hours is provided by the American Nephrology Nurses’ Association (ANNA). American Nephrology Nurses’ Association is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center Commission on Accreditation. ANNA is a provider approved by the California Board of Registered Nursing, provider number CEP 00910. This CNE article meets the Nephrology Nursing Certification Commission’s (NNCC’s) continuing nursing education requirements for certification and recertification.

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sive episode itself and to other longterm cardiovascular risks inherent in chronic kidney disease (Burton, Jefferies, Selby, & McIntyre, 2009; Jefferies, Bhupinder, Schiller, Moran, & McIntyre, 2011; McIntyre, 2010a). Reduction in myocardial blood flow during IDH can result in cardiac stunning (Burton et al., 2009) with subsequent structural and fibrotic changes contributing to arrhythmias, cardiac fibrosis, and sudden cardiac death (Dorairajan, Chockalingam, & Misra, 2010). Reduced cerebral flow from IDH may result in stroke (Covic & Voroneanu, 2013) or transient ischemic events in a population already susceptible to subdural and intracranial hemorrhage (Davenport, 2006). Altered thrombogenicity arising from combinations of increased shear stress, inflammatory mediators, and endothelial abnormalities provides increased risks for thrombus formation (Schreiber, Jr., 2001) and increased rates of vascular access thrombosis (Lewicki, Kerr, & Polkinghorne, 2013). IDH episodes interrupt the hemodialysis procedure, greatly reducing the efficacy of the treatment (Ellis, 2011) and resulting in increased mortality (National Kidney Foundation [NKF], 2005). Overwhelmingly, the nephrology literature describes a burdensome cascade of adverse, diverse, and critical pathophysiological consequences that are a direct result of repeated IDH episodes (Davenport, 2009; Shoji, Tsubakihara, Fujii, & Imai, 2004). Aberrations in one or more of four critical determinants to IDH (reduction of cardiac output, excessive ultrafiltration [UF] rate, reduction of effective peripheral vascular resistance, and reduction in venoconstriction) contribute to reduced perfusion pressure, which results in cellular hypoperfusion (Covic & Voroneanu, 2013; Daugirdas, 2001; Davenport, 2013; Dorairajan et al., 2010; Eldehni & McIntyre, 2012; McIntyre et al., 2011; Stafie et al., 2010). The subsequent effects have been incorporated into a critical pathway, as they arise from repeated IDH episodes (see Figure 1). The imperative for both preventative strategies and early recognition

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Table 1 Current Definitions of Intradialytic Hypotension Definition

Source

A decrease in systolic blood pressure by greater than 20 mmHg or a decrease in MAP by greater than 10 mmHg with symptoms.

Kooman et al., 2007; National Kidney Foundation, 2006

SBP lower than 110 mmHg, with SBP drop greater than 30 mmHg from the predialysis level.

Imai et al., 2006

Decrease in SBP by greater than 20 mmHg or to below 100 mmHg with symptoms.

Stafie et al., 2010

SBP drop of greater than 20 mmHg, with symptoms such as dizziness, nausea, vomiting, or cramps.

Nesralla et al., 2013

A drop in MAP of 20 mmHg or greater.

Tomita et al., 2001

A decrease of more than 40 mmHg in SBP and 20 mmHg in DBP.

Dheenan & Henrich, 2001

BP drop (greater than 30 mmHg SBP) requiring saline infusion.

Ok et al., 2013

Notes: SBP = systolic blood pressure; DBP = diastolic blood pressure; MAP = mean arterial blood pressure.

of IDH is borne by all nephrology care clinicians. Yet the critical management and treatment activities in dealing with IDH are carried out by nephrology nurses.

Definitions of Intradialytic Hypotension While several proactive strategies may be utilized to minimize the likelihood of IDH, it is the measurement of blood pressure that the nurse relies on most to confer information about the patient’s immediate intradialytic cardiovascular status (Ferns, 2010; Hossli, 2005; McGhee & Bridges, 2002). Given the complexities of IDH, the literature offers varying definitions, as demonstrated in Table 1. Agarwal (2012, p. 593) notes that in research the “difference in the way IDH is defined also appears to be a major source of variation from one study to the next. Variable definitions create problems with interpretation of the study.” These study definitions can also be challenging to apply clinically when staff are preventing or managing an IDH episode.

Symptomatic and Asymptomatic Variation Additional to the problem of variation in IDH definition is inclusion of asymptomatic episodes as IDH. Davenport (2006) states that such “variation is because of the definition, varying from symptomatic hypotension requiring active treatment to an asymptomatic percentage fall in systolic blood pressure” (p. 162). Thus, recognition of both symptomatic and asymptomatic hypotension is important, particularly regarding the consequences of cellular hypoperfusion (Chesterton et al., 2010). Some researchers have alluded that asymptomatic hypotension is just as critical as episodes with symptoms (Dubin, Owens, Gasper, Ganz, & Johansen, 2011; McIntyre, 2010b; Quader et al., 2014). Yet relative asymptomatic hypotension is not reflected in the definitions offered by industry leaders (Kooman, et al., 2007; NKF, 2005, 2006). Regarding intradialytic blood pressure assessment, the importance of the systolic blood pressure in offer-


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Figure 1 Critical Pathway Indicating Conditions Directly Related to Intradialytic Hypotension (IDH) Leading to Death

↓Cardiac output

↓TPR/PVR

IDH

↑UFR

↓ Venoconstriction ↓Perfusion pressure

↓Neuronal blood supply

Cellular hypoperfusion

↓ Cerebral blood flow

↓Splanchnic blood flow

↓ Myocardial blood flow (↓DBP) Axonal and myelin sheath degradation

Mesenteric ischemia

IBRS

↓Capillary flow

RWMA ↑Gut permeability

Cerebral ischemia

↑Cardiac fibrosis Endotoxin into circulation

↑Cognitive deficits Stroke Cardiac ischemia/ heart failure

Cellular ischemia

Adenosine release

↑Vasodilation Sudden cardiac death

Post-dialysis fatigue

↑Inflammatory processes (↑CRP)

Malnutrition (↓albumin)

Depression Death

Notes: UFR = ultrafiltration rate, TPR/PVR = total peripheral resistance/peripheral vascular resistance, IBRS = impaired baroreflex receptor sensitivity, RWMA = regional wall motion abnormalities, CRP – C-reactive protein. Sources: Covic & Voroneamu, 2013; Daugirdas, 2001; Dorairajan, Chockalingam, & Misra, 2010; McIntyre et al., 2011; Sherman, 1988; Shinzato et al., 1994; Stafie et al., 2010.


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ing an initial indication of patient condition is reflected by reference within nearly all IDH definitions (see Table 1). Additionally, the diastolic value has been explained in its expression of peripheral resistance and vascular compliance (Ie et al., 2005; Zoccali, 2003), and studies indicate that lower values of both systolic and diastolic blood pressures pre-, during, and post-hemodialysis are associated with significant increased mortality risks (Thijssen et al., 2013; van der Sande, Kooman, & Leunissen, 2000). Ultimately, all blood pressure (BP) markers are essential: “consequently, diagnosis and treatment of BP (in hemodialysis) must be considered in respect of pre-/post-dialysis mean arterial pressure and especially pulse pressure values, not just depending on pre-/post-dialysis systolic and diastolic pressure values” (Kovacic, Roguljic, Bacic, & Bosnjak, 2003, p. 360). Therefore, the overarching aim of this research was to investigate nephrology nurse knowledge in the prevention and management of IDH. In particular, this study aimed to explore practice habits for hypotension prevention, determine the importance nurses ascribe to specific blood pressure measures, and identify barriers and enablers for offering improvements in early recognition and IDH management.

Methods Theoretical Framework The theoretical approach guiding this study was the Knowledge to Action (KTA) framework, as interpreted through its diagrammatic action cycle, which offers a practical and succinct approach to the acceptance of new knowledge for the work environment (Graham et al., 2006). The KTA process relies on the components of problem identification and solution (knowledge creation) through acknowledgement of barrier and contextual issues that progress through an implementation and evaluation (action) phase (Graham et al., 2006; Sudsawad, 2007). This framework

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was considered relevant in establishing practical guidance from problem identification (IDH) through to possible solution implementation (IDH amelioration).

Ethical Standards The ethical principles of autonomy, beneficence, non-maleficence, and justice were applied in this study. The ethical requirements as per the Australian National Statement on Ethical Conduct in Human Research (National Health and Medical Research Council, 2007) were followed, and the study commenced once approval was granted from the appropriate Human Research and Ethics Committee. Participation was voluntary, and consent was implied by completion of the survey as specified on the plain language statement page of the survey.

2013. Links to the survey were emailed within the monthly email newsletter of the RSA, inviting voluntary participation. Data were aggregated as individual surveys were completed, with the total data results extracted at the end of the three-month period. Data from the electronic survey were imported into IBM SPSS Statistics version 22 (Armonk, NY: IBM Corp). All variables were summarized using simple frequency and descriptive techniques (e.g., frequency count, percentage, mean, and standard deviation). Depending on response categories, Chi-square test for independence, independent samples t-tests, or analysis of variance (ANOVA) were conducted to compare responses based on demographic characteristics, with p < 0.05 considered statistically significant.

Results

Participants Participants were Australian and New Zealand registered nurses working in hemodialysis settings who were sourced through the membership database of the Renal Society of Australasia (RSA). The RSA has a total membership of 1,373, and most of these members (n = 1,285) are registered nurses.

The Survey A survey was developed by the authors that included questions to identify the demographic characteristics of participants and the facilities in which they worked, followed by a series of quantitative questions to examine participants’ blood pressure knowledge and practice patterns (see Table 2). A final open-ended question offered the participants the opportunity to include any additional comments, concerns, or opinions they had in regard to IDH. The survey tool was pilot tested with five nurses to increase face validity, resulting in minor changes to the survey tool prior final dissemination.

Data Collection and Analysis The survey was an online webbased questionnaire available for completion over a three-month period in

A total of 198 nurses responded to the survey. Of these respondents, 25 completed only the demographic section of the survey and were therefore excluded from analysis, resulting in a final sample of 173 nurses. The demographic characteristics of participants and the facilities in which they worked are found in Table 3. Participants represented a breadth of experience ranging from less than two years (4.6%) to over 20 years (17.9%). The majority of participants had completed a post-graduate nephrology qualification (generally a 12 month Graduate Certificate), and just over one-third had completed nephrologyspecific BP education in the last 12 months. The highest proportions of respondents worked in facilities with the capacity to treat over 50 patients (39.9%), with only 9.8% working in facilities of less than 10 patients. The majority of participants worked in a hospital-based facility, and half of the sample was based in regional, rural, or remote locations.

Defining Intradialytic Hypotension Participants were provided with four of the most commonly used def-


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Table 2 Survey Questions 1.

How many years in total, have you worked in hemodialysis? < 2 years 2-5 years 6-10 years 11-15 years 16-20 years

20 years+

2.

Do you have a post-graduate renal/nephrology qualification (hospital, TAFE or university)? Yes No

3.

Have you received any blood pressure education in the last twelve months? Yes No

4.

How many patients does your hemodialysis facility treat? 1 to 10 11 to 25 26 to 50 > 50

5.

Your hemodialysis facility is: Hospital based Non-hospital based

6.

The location of your hemodialysis facility is: Metropolitan Regional (non-metropolitan)

Rural

Remote

7.

In which state, territory or island is your dialysis facility?

8.

Which of the following BEST defines intradialytic hypotension: a. A drop in blood pressure accompanied by adverse symptoms which require intervention b. A drop in blood pressure which may or may not be accompanied by adverse symptoms c. A drop in systolic blood pressure greater than 20 mmHg d. A drop in mean arterial pressure greater than 10 mmHg

9.

Rank the order of importance of the following BP measures when assessing intradialytic hypotension (from 1 most important through 4 least important): a. Systolic b. Diastolic c. Mean arterial pressure d. Pulse pressure

10. What proportion of dialysis sessions in your facility results in symptomatic hypotension? 0% to 2% 3% to 5% 6% to 10% 11% to 20% 21% to 50% > 51% 11. How successful are you in managing to prevent intradialytic hypotension? Always Nearly always Sometimes Never 12. Do you think the routine use of proactive intradialytic measures can prevent the occurrence of intradialytic hypotension? Yes No 13. Which of the following proactive intradialytic actions do you routinely use? a. Ultrafiltration (UF) profiling b. Sodium modelling c. Isolated ultrafiltration with dialysis d. Strict adherence to a maximum UF goal e. Strict adherence to a maximum UF rate f. Reduction in dialysate temperature g. Use of blood volume monitoring h. Reduction of blood flow (Qb) i. Other: _______________________________________________________


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initions of IDH from the nephrology literature (Agarwal, 2012; Kooman et al., 2007; Nesralla et al., 2013; Tomita et al., 2001) and asked to select the one that best defined IDH from their perspective. The majority of participants (n = 118, 68.2%) selected “a drop in blood pressure which may or may not be accompanied by adverse symptoms” as the most appropriate definition of IDH; 28 (16.2%) selected “a drop in blood pressure accompanied by adverse symptoms which require intervention,” 20 (11.6%) selected “a drop in systolic blood pressure of greater than 20 mmHg,” and 7 (4%) selected “a drop in mean arterial pressure greater than 10 mmHg.” The variability in responses reflects the ambiguity in definitions of IDH found in the nephrology literature, but importantly, the majority of participants correctly identified that a hypotensive episode does not need to be symptomatic to proffer significant harm, as has been recently recognized (Eldehni & McIntyre, 2012; McIntyre, 2010b; Sherman & Kapoian, 2011).

Most Important Blood Pressure Measure Systolic blood pressure measure was the most important selected consideration in patient assessment for IDH (n = 101, 58.4%), while the majority of participants (n = 96, 55.5%) selected pulse pressure as the least important consideration (see Figure 2). Mean arterial pressure had the widest response variance, with approximately one-quarter of participants (23% to 28%) selecting each of the four response options.

Frequency and Prevention of IDH Cumulatively, 91% of participants in this study estimated that IDH occurred in 20% of treatments or less. A total of 83 participants (48.0%) reported that 0% to 5% of all hemodialysis sessions in their facility result in IDH, 44 participants (25.4%) estimated 6% to 10%, and 31 participants (17.9%) estimated 11% to 20% of all hemodialysis sessions. Thirteen par-

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Table 2 (continued) Survey Questions 14. For any routinely used actions in the previous question, please rank in order of preference starting at 1 as most preferred to 8 as least preferred: a. Ultrafiltration (UF) profiling b. Sodium modelling c. Isolated ultrafiltration with dialysis d. Strict adherence to a maximum UF goal e. Strict adherence to a maximum UF rate f. Reduction in dialysate temperature g. Use of blood volume monitoring h. Reduction in blood flow rate (Qb) i. Other: ______________________________________________________ 15. Rate the importance of the following strategies in preventing intradialytic hypotension (from 1 as very important through 7 as not important): a. Extension of dialysis time (longer sessions) b. Intensive patient fluid restriction education c. Intensive patient sodium intake education d. Increase in frequency of dialysis sessions offered per week e. Frequent assessment of dry weight (ideal body weight) 16. Please indicate your agreement with the following statements: (Strongly Agree/Agree /Neutral/Disagree/Strongly Disagree) a. Older patients are more likely to develop intradialytic hypotension b. Diabetic patients are more likely to develop intradialytic hypotension c. Every patient I dialyse could become hypotensive d. I intuitively know if a patient will develop intradialytic hypotension In thinking about the management of the prevention of intradialytic hypotension, would you like to make any further comments?

ticipants (7.5%) reported that 21% to 50% of hemodialysis sessions resulted in IDH in their facility, and the remaining two participants reported that IDH occurred in over 50% of sessions. The majority of participants reported that they were nearly always (n = 119, 68.8%) or always (n = 21, 12.1%) successful in preventing IDH. The remaining 33 participants (19.1%) indicated they were sometimes successful, and no one reported never being successful. Participants were asked about their preferred choice of effective activities used regularly for IDH prevention. Figure 3 indicates how many participants used each of the nominated intradialytic strategies to prevent IDH in their facility. Ultrafiltration profiling and blood volume monitoring were the most frequently used strategies, while sodium modelling was the least common. This section of the survey was designed to explore current practice, and there are no specific right or wrong answers.

General Knowledge of IDH Table 3 Characteristics of Participants and the Facility in Which They Worked Variable Years working in hemodialysis

Postgraduate nephrology qualification Nephrology BP education in past 12 months Number of patients at the facility

Type of facility Location of the facility

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Response Less than 2 years 2 to 5 years 6 to 10 years 11 to 15 years 16 to 20 years 20+ years Yes No Yes No 1 to 10 11 to 25 26 to 50 50+ Hospital Non-hospital Metropolitan Regional Rural Remote

n

%

8 21 52 40 21 31 114 59 60 113 17 36 51 69 118 55

4.6 12.1 30.1 23.1 12.1 17.9 65.9 34.1 34.7 65.3 9.8 20.8 29.5 39.9 68.2 31.8

86 55 26 6

49.7 31.8 15.0 3.5

Fifteen participants did not respond to the last quantitative section of the survey, resulting in a final sample of 158. Of these, 40 participants (25.3%) strongly agreed, and 79 participants (50.0%) agreed that patients of an older age are more likely to develop IDH; only two participants strongly disagreed. A larger proportion of participants strongly agreed (n = 69, 43.7%) that patients with diabetes are more likely to develop IDH, and an additional 55 participants (34.8%) agreed; only one person selected strongly disagree. Similarly, 87.3% of participants either agreed (n = 67) or strongly agreed (n = 71) that every patient they dialyze could become hypotensive. The item “I intuitively know if a patient will develop IDH” elicited mixed responses, with the highest proportion of participants (n = 54, 34.2%) selecting the neutral response option; only 13 participants (8.2%) selected strongly agree (see Figure 4).


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Figure 2 Perceived Importance of Four Blood Pressure Measures When Assessing Intradialytic Hypotension (IDH) 1 (Most Important)

2

3

4 (Least Important)

100

Percentage of Responses

90 80 70 60 50 40 30 20 10 0

Systolic BP

Diastolic BP

Mean Arterial Pressure

Pulse Pressure

Blood Pressure Measure

Figure 3 Strategies Used to Prevent Intradialytic Hypotension (IDH)

Strategies Used to Prevent IDH

Ultrafiltration profiling 75.7 Blood volume monitoring 61.8 Dialysate temperature reduction 52.6 Isolated ultrafiltration with dialysis 51.4 Maximum ultrafiltration rate 47.4 Maximum ultrafiltration goal 45.1

Additional Comments about the Management and Prevention of IDH

Reduction blood flow rate (Qb) 23.7 Sodium modelling 10.4 0

20

40

60

80

100


Comparison of Responses Based on Nurse and Facility Demographics Responses to survey items were compared on the basis of participant


ification (51.6%) reported that they routinely use isolated ultrafiltration with hemodialysis, compared with participants without a qualification (32.9%) (c2 = 5.66, p = 0.02, phi = 0.18). Responses were also compared on the basis of the characteristics of the facility in which participants worked. Participants were asked to respond based on their own practice; however, it is possible that this may reflect the general practice in their unit. Three statistically significant findings were identified that were associated with facility size and location. First, the use of a maximum ultrafiltration goal differed based on facility size (c2 = 13.5, p = 0.004, V = 0.26). Of the 21 respondents who work in facilities with 1 to 10 patients, only one respondent (4.8%) indicated using strict adherence to a maximum UF goal, compared with 39% to 50% of respondents working in larger facilities. Second, strict adherence to a maximum UF goal differed based on geographic locations (c2 = 13.21, p < 0.001, V = 0.26). This strategy was routinely used by 58% of the 62 participants from regional facilities, compared with only 30% to 31% of participants from metropolitan and rural/remote facilities. Third, the use of sodium modelling was uncommon across all geographic locations, but it was particularly rare in regional facilities, with only one respondent out of 62 (1.6%) reporting routinely using this strategy. In comparison, 11% to 13% of participants at metropolitan and rural/ remote locations indicated they themselves routinely use sodium modelling (c2 = 6.30, p = 0.04, V= 0.18).

demographics (years of experience, nephrology qualification, and recent BP training). Results indicated that higher proportions of participants with a post-graduate nephrology qual-

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Seventy-one respondents (37%) provided additional comments, totalling 120 individual suggestions (i.e., some made more than one comment). The responses have been categorized into four themes: 1) the importance of nurse assessment, monitoring/actions/responsibility; 2) presence and use of machine technologies/tools/policy; 3) patient responsi-

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Figure 4 Participant Responses to the Item “I intuitively know if a patient will develop Intradialytic Hypotension (IDH)”


100 90 80 70 60 50 40 30 20 10 0

8.2

29.1

34.2

22.8

5.7

Strongly Agree

Agree

Neutral

Disagree

Strongly Disagree

Response Options

Table 4 Themes from Open-Ended Question and Frequency Number of Comments

Themes 1.

The importance of nurse assessment, monitoring/actions/ responsibility

56

2.

Presence and use of machine technologies/tools/policy

36

3.

Patient responsibilities/fluid-dietary restrictions

17

4.

Miscellaneous suggestions

11

bilities/fluid-dietary restrictions; and 4) miscellaneous suggestions (see Table 4). Within theme 1, 22 comments stressed the importance of individualized, clinical patient assessment, and ongoing intradialytic monitoring. This included the importance of knowing the patient, recognizing “what works” for this patient, and taking the time to formulate individualized dialysis care plans. Also within theme 1, there were seven comments about the importance of further nephrology education, five comments about the importance of dry weight assessment, and three comments about being alert to particular risk fac-

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tors. In theme 2, nine comments suggested extending hemodialysis times or frequency, and six suggested UF profiling as advantageous. Four commented on maintaining a maximal fluid removal goal, and two requested policy or protocol guidance. Within theme 3, a remark was made on patients being responsible for selfcare (eight comments), on avoiding food intake during dialysis (five comments), and patients taking care with medication administration (four comments). Theme 4 included the comment that IDH is an incident and not acceptable, and a comment that each patient’s lifestyle choices should be respected.

Discussion The findings from Australian and New Zealand nurses in this study suggest an ambiguity in defining intradialytic hypotension, including uncertainty of the significance of asymptomatic hypotensive episodes – factors acknowledged within nephrology literature (Chesterton et al., 2010; Davenport, 2006). While the majority of respondents recognized the overwhelming importance of the systolic blood pressure value in assessing for the occurrence or likelihood of IDH, scholars have suggested that diastolic blood pressure, mean arterial pressure, and pulse pressure are simultaneously just as significant, and all have something of value to add to the intradialytic monitoring of the patients on hemodialysis (Ie et al., 2005; Kovacic et al., 2003; Thijssen et al., 2013; Zoccali, 2003). This survey has showcased the intradialytic strategies routinely used for IDH minimization, and these practice patterns can be compared with literature recommendations. Ultrafiltration profiling was performed by 76% of Australian and New Zealand nurses in this study. This finding is clinically significant because it suggests acknowledgment of the importance of staggered fluid removal in its principled allowance for vascular refill as may be tailored to a patient’s specific tolerance (Davenport, 2009, 2011; Dheenan & Henrich, 2001; Yung, 2008). Nurses may not always have the hemodialysis machine capability to perform such profiles, but innovation to those available may lead to enhanced refill patterning in the form of UF pausing for individual patient benefit (Bradshaw, Ockerby, & Bennett, 2011; Yung, 2008). UF pausing is different than profiling because it may be implemented in the moment, rather than strategically planned from the outset. However, its use is still suggestive of the recognition for vascular refill, in line with ongoing patient assessment, which remains the purpose behind such practices.


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Although not frequently used by nurses in this study, sodium modelling (performed routinely by only 10% of respondent nurses) offers optimal fluid removal with minimum adversity (Davenport, 2011). Sodium modelling has fallen out of favour since the Dheenan and Henrich (2001) study advocating sodium modelling “using a step-wise protocol...[as] most effective in stabilizing blood pressure” (p. 1179). If not performed by experienced practitioners, there is the possibility of sodium accumulation, which augments thirst and increases interdialytic fluid gains (Stiller, Bonnie-Schoren, Grassmann, Uhlenusch-Korwer, & Mann, 2001), which may ultimately increase IDH incidence. Fifty-one percent (51%) of nurses in this study utilize isolated ultrafiltration; nurses with a nephrology qualification were more likely to do so. It may be speculated that this practice requires additional knowledge and confidence gained through clinical and theoretical experience, although its utility is still debated (Dheenan & Henrich, 2001). The NKF’s Kidney Disease Outcomes Quality Initiative (KDOQI) suggests that “isolated ultrafiltration...[is] associated with decreased incidence of IDH and improved hemodynamic stability” (NKF, 2005, p. S79). However, the European Best Practice Guidelines on hemodynamic instability propose that “isolated ultrafiltration followed by isovolaemic dialysis may actually increase the risk for IDH because of the high ultrafiltration rates” (Kooman et al., 2007, p. ii39). Additionally, isolated UF time may detract from overall dialysis time, impacting on dialysis adequacy and longevity outcomes. Nurses from Australia and New Zealand tend to use both maximum UF rate (47%) and maximum UF goal (45%); and maximum UF goal in particular was shown to be more common in larger hemodialysis facilities. The exact reason for this is not clear; however, it may be that larger hemodialysis units require more policies to ensure good practice gover-


nance as opposed to smaller units where the nurse manager has a closer view of every hemodialysis treatment. Within restrictions based on maximum UF rate, the limit is ascribed as an hourly rate rather than an overall goal per treatment. The Dialysis Outcomes and Practice Patterns Study (DOPPS) reported an increase in all-cause mortality for UF rates greater than 10mL/hour/kg, associating this mortality to increased IDH (Saran et al., 2006). The authors additionally suggest longer treatment times being associated with lower mortality, inferring a link between higher UF rate and cardiovascular mortality, yet ultimately, they concede “this is an observational study and causality is not proven” (Saran, et al., 2006, p. 1227). Dialysate temperature reduction has been shown to decrease IDH incidence, chiefly through reduction of core body temperature and subsequent maintenance of vascular tone (Damasiewicz & Polkinghorne, 2011; Ellis, 2011; Palmer, 2009; Palmer & Henrich, 2008). It is recommended as an effective practice (Dheenan & Henrich, 2001), and frequently used in Australia and New Zealand. Yet with such recognized benefit in protection against IDH, it is not clear why this intervention is not used in all facilities. It may be that many facilities already have lowered the dialysate temperature, which may be unknown to some nurses. Modern hemodialysis machines have default programming, allowing lower dialysate temperature settings as standard practice and routine (daily) checking of dialysate temperature, which is policy in many units. Recommendations for blood volume monitoring within the literature vary considerably (Dasselaar, 2007; Davenport, 2009; Lewicki et al., 2013). Although the choice for use depends on machine technology availability, there is a tendency for staff members to rely on a significant numerical value in ascribing volume status to their patients, which is contrary to recommendations (Lewicki et al., 2013; Nesralla et al., 2013). A treat-

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ment session commencing from fluid overload and ending in euvolemia may appear numerically identical to a session commencing at euvolemia and ending in dehydration (Lindley & Keane, 2013), so interpretation of the graphed refill pattern, the critical line, is essential. Reducing blood flow may be an example of unit-based practice being handed down from nurse to nurse because there is no evidence to suggest this strategy has any effect on IDH. Reducing blood flow rate (BFR) is “a legacy of the old days of dialysis therapy, when such a reduction might have lessened the vasodilatory effect of acetate influx as well as reduce dialyzer blood volume” and is “no longer a helpful intervention” (Sherman & Kapoian, 2011, p. 1397). European Best Practice Guidelines on hemodynamic instability suggest “slowing BFR is sometimes used in treatment of IDH. However, no data are present that assessed the effect of this on BP response” (Kooman et al., 2007, p. ii43). Only one article questioning the practice has been located. The study was designed to examine the effect of altering BFR on BP during hemodialysis, although their data were not obtained during periods of IDH. Still, they concluded that “BPs are maintained higher at higher BFRs as compared with lower BFRs” and “current data do not support lowering of BFRs during hypotensive episodes” (Trivedi, Kukla, Prowant, & Lim, 2007, p. 427). Australian and New Zealand nurses confirmed the importance of sustained patient assessment, vigilant intradialytic monitoring, nephrology nurse education, patient education, acknowledging the importance of longer treatment sessions in both ameliorating IDH, and improving outcomes for patients on dialysis. Yet participants also expressed frustration at having minimal and inconsistent policy regarding IDH management plans and lack of clear industry guidelines in promoting such strategies. In considering the information gleaned from this study within the Knowledge to Action framework, it is

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Table 5 Barriers and Enablers in the Nurse Management of Intradialytic Hypotension (IDH)

Variance in defining IDH

Nurse awareness and insistence on individualized patient assessment

Ambiguity of significance of asymptomatic IDH

Majority nurse recognition of asymptomatic IDH significance

Lack of industry guidelines for advanced recognition of IDH and policy

Nurse request for industry policy guidance in IDH management

the symptomatic episodes that are memorable. But this has not been considered by the 31.8% who chose a definition that did not necessarily account for asymptomatic IDH. This further highlights the problem of ambiguity within industry guidelines, which probably compounds the problems of early IDH recognition and makes no account for the invisible effects of asymptomatic, or relative, IDH.

Nurse educational inconsistency as informs practice variation

Nurse request for further education and standardization of practice

Limitations

Ambiguity in ascribed importance of specific blood pressure measures

Nurse insistence on significance of continual BP monitoring

Unit cultural habits informing practice

Nurse awareness in suggestion of unit cultural influences

Propensity to continue out-dated practices

Nurse awareness of importance of practice advancement, education

Barriers

possible to additionally highlight barriers that impede successful management of IDH as well as several enablers, which are derived both from survey question responses and from individual nurse comment. These barriers and enablers are suggested in Table 5. Respondent comments acknowledged the need for continual individualized patient assessment and ongoing intradialytic monitoring. Nurses frequently stated this importance along with the value of knowing the patient. This was within the context of knowing patient responses to specific treatments, knowing their individual tolerances, understanding changes in their wellness (and acknowledging general, interdialytic deterioration), and knowing unique patient histories. While nurses are pragmatic in their preference to what works and what does not work, their variable responses to the subjective statement “I intuitively know if a patient will become hypotensive” are interesting (see Figure 4). Intuition as a form of knowing is well acknowledged and accepted within nursing literature (Benner & Tanner, 1987; Rew & Barrow, 1987), and includes a subconscious assess-

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Enablers

ment that may be rationalized in hindsight or an embodied awareness, which is trusted by the nurse in the moment (Lyneham, Parkinsons, & Denholm, 2008). It could be argued that the longer a nurse cares for a patient, given the chronic status of the hemodialysis population, the more the patients are “known” by the nurse. Yet the variability of responses to this question suggests a lack of trust in this important way of knowing. When considering which patients are more likely to become hypotensive, the classification of some patients as hypotensive-resistant or hypotensive-prone by some researchers (Graziani et al., 2010) as well as the proposition of categorizing hypotensive likeliness (Sulowicz & Radziszewski, 2006), suggests that the comment “all patients I dialyze could become hypotensive” is not necessarily accurate. The overwhelming response of 87% of survey respondents otherwise agreeing with this statement, however, may suggest a cautiousness that cannot be ignored. While the majority of nurses recognize the significance of asymptomatic episodes as important in choosing a definition of hypotension, it is

The first limitation of this study was that the sample purposefully selected for this study represents a group of nurses who are voluntary members of the RSA, and as such, may not be truly representative of the Australian and New Zealand nephrology nursing workforce as a whole. The study was also limited by the survey tool. Although the survey questions were piloted and minor changes made, no further face, content, or construct validity, or reliability testing were undertaken. This is recommended for future research.

Conclusion The findings from this study of Australian and New Zealand nurses have suggested some ambiguity in adequately defining IDH, which may delay early recognition. Failure to identify the relevance of asymptomatic episodes, as inferred in this study, may add to this problem. The overwhelming suggestion of the systolic value as the most important blood pressure value when assessing for IDH suggests a dilution of physiological reasoning in considering the pathology of hypotension and the multifactorial importance of all BP measures. Australian and New Zealand nurses have pragmatically insisted on the importance of individualized patient assessment, of the imperative of continual intradialytic monitoring, and of the necessity of knowing the patient as an individual. They have commented on the need for continual nephrology education, and requested guidance in IDH and


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fluid removal policy. This survey has show-cased the intradialytic strategies this nurse sample consider significant and which of these are routinely used for IDH minimalization. References Agarwal, R. (2012). How can we prevent intradialytic hypotension? Current Opinion in Nephrology and Hypertension, 21(6), 593-599. doi: 10.1097/ MNH.0b013e3283588f3c Benner, P., & Tanner, C. (1987). How expert nurses use intuition. American Journal of Nursing, 87(1), 23-34. Bradshaw, W., Ockerby, C., & Bennett, P. (2011). Pre-emptively pausing ultrafiltration to minimise dialysis hypotension. Renal Society of Australasia Journal, 7(3), 130-134. Burton, J.O., Jefferies, H.J., Selby, N.M., & McIntyre, C.W. (2009). Hemodialysis-induced cardiac injury: Determinants and associated outcomes. Clinical Journal of American Society of Nephrology, 4(5), 914-920. doi:10. 2215/CJN.03900808 Chesterton, L.J., Selby, N.M., Burton, J.O., Fialova, J., Chan, C., & McIntyre, C.W. (2010). Categorization of the hemodynamic response to hemodialysis: The importance of baroreflex sensitivity. Hemodialysis International, 14(1), 18-28. doi:10. 1111/j.1542-4758.2009.00403.x Covic, A., & Voroneanu, L. (2013). Dialysis fata morgana: Can we finally successfully tackle intradialytic hypotension with plasma sodium biofeedback systems? Nephrology Dialysis and Transplantation(28), 250-253. doi:10. 1093/ndt/gfs434 Damasiewicz, M., & Polkinghorne, K. (2011). Intra-dialytic hypotension and blood volume temperature monitoring. Nephrology 16, 13-18. doi:10. 1111/j.1440-1797.2010.01362.x Dasselaar, J.J. (2007). Relative blood volume based biofeedback during haemodialysis. Journal of Renal Care, 33(2), 59-65. doi:10.1111/j.1755-6686. 2007.tb00041.x Daugirdas, J.T. (2001). Pathophysiology of dialysis hypotension: An update. American Journal of Kidney Disease, 38(4, Suppl. 4), S11-17. doi:10.1053/ ajkd.2001.28090 Davenport, A. (2006). Intradialytic complications during hemodialysis. Hemodialysis International, 10, 162-167. doi: 10.1111/j.1542-4758.2006.00088.x


Davenport, A. (2009). Can advances in hemodialysis machine technology prevent intradialytic hypotension? [Editorial]. Seminars in Dialysis, 22, 231-236. doi:10.1111/j.1525-139X. 2009.00614.x Davenport, A. (2011). Using dialysis machine technology to reduce intradialytic hypotension. Hemodialysis International, S37-S42. doi:10.1111/ j.1542-4758.2011.00600.x Davenport, A. (2013). Balancing risks: Blood pressure targets, intradialytic hypotension and ischemic brain injury. Seminars in Dialysis, 27(1), 1315. Dheenan, S., & Henrich, W.L. (2001). Preventing dialysis hypotension: A comparison of usual protective maneuvers. Kidney International, 59(3), 11751181. doi:10.1046/j.1523-1755.2001. 0590031175.x Dorairajan, S., Chockalingam, A., & Misra, M. (2010). Myocardial stunning in hemodialysis: What is the overall message? Hemodialysis International, 14(4), 447-450. doi:10.1111/ j.1542-4758.2010.00495.x Dubin, R., Owens, C., Gasper, W., Ganz, P., & Johansen, K. (2011). Associations of endothelial dysfunction and arterial stiffness with intradialytic hypotension and hypertension. Hemodialysis International, 15(3), 350358. doi:10.1111/j.1542-4758.2011. 00560.x Eldehni, M., & McIntyre, C. (2012). Are there neurological consequences of recurrent intradialytic hypotension? Seminars in Dialysis, 25(3), 253-256. Ellis, P. (2011). Back to basics: Complications of haemodialysis. Journal of Renal Nursing, 3(5), 230-233. Ferns, T. (2010). Mean arterial blood pressure and the assessment of acutely ill patients. Nursing Standard, 25(12), 4044. doi:10.7748/ns2010.11.25.12.40. c8113 Graham, I., Logan, J., Harrison, M., Straus, S., Tetroe, J., Caswell, W., & Robinson, N. (2006). Lost in knowledge translation: Time for a map? Journal of Continuing Education in the Health Professions, 26(1), 13-24. doi:10.1002/chp.47 Graziani, G., Finazzi, S., Mangiarotti, R., Como, G., Fedeli, C., Oldani, S., ... Badalamenti, S. (2010). Different cardiovascular responses to hemodialysis-induced fluid depletion and blood pressure compliance. Journal Of Nephrology, 23(1), 55-61.

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Henrich, W.L. (2008). Intradialytic hypotension: A new insight to an old problem. American Journal of Kidney Diseases, 52(2), 209-210. doi:10.1053/ j.ajkd.2008.06.003 Hossli, S.M. (2005). Clinical management of intradialytic hypotension: Survey results. Nephrology Nursing Journal, 32(3), 287-292. Ie, E., De Backer, T., Carlier, S., Vletter, W., Nette, R., Weimar, W., & Zietse, R. (2005). Ultrafiltration improves aortic compliance in haemodialysis patients. Journal of Human Hypertension, 19(6), 439-444. doi:10.1038/ sj.jhh.1001813 Imai, E., Fujii, M., Kohno, Y., Kageyama, H., Nakahara, K., Hori, M., & Tsubakihara, Y. (2006). Adenosine A1 receptor antagonist improves intradialytic hypotension. Kidney International, 69(5), 877-883. doi: 10.1038/sj.ki.5000088 Jefferies, H., Bhupinder, V., Schiller, B., Moran, J., & McIntyre, C.W. (2011). Frequent hemodialysis schedules are associated with reduced levels of dialysis-induced cardiac injury (myocardial stunning). Clinical Journal of American Society of Nephrology, 6(6), 1326-1332. doi:10.2215/CJN.05200 610 Kooman, J., Basci, A., Pizzarelli, F., Canaud, B., Haage, P., Fouque, D., ... Vanholder, R. (2007). EBPG guideline on haemodynamic instability. Nephrology Dialysis and Transplantation, 22(Suppl. 2), ii22-ii44. doi:10. 1093/ndt/gfm019 Kovacic, V., Roguljic, L., Bacic, B., & Bosnjak, T. (2003). Mean arterial pressure and pulse pressure are associated with different clinical parameters in chronic haemodialysis patients. Journal of Human Hypertension, 17(5), 353. doi:10.1038/sj.jhh.1001557 Lewicki, M., Kerr, P., & Polkinghorne, K. (2013). Blood pressure and blood volume: Acute and chronic considerations in hemodialysis. Seminars in Dialysis, 26(1), 62-72. doi:10.1111/ sdi.12009 Lindley, E., & Keane, D. (2013). Are haemodialysis patients at risk of excessive dehydration? Renal Society of Australasia Journal, 9(3), 110-111. Lyneham, J., Parkinsons, C., & Denholm, C. (2008). Explicating Benner’s concept of expert practice: Intuition in emergency nursing. Journal of Advanced Nursing, 64(4), 380-387. doi:10. 1111/j.1365-2648.2008.04799.x

165



McGhee, B., & Bridges, M. (2002). Monitoring arterial blood pressure: What you may not know. Critical Care Nurse, 22(2), 60-78. McIntyre, C.W. (2010a). Haemodialysisinduced myocardial stunning in chronic kidney disease: A new aspect of cardiovascular disease. Blood Purification, 29(2), 105-110. doi:10.1159/ 000245634 McIntyre, C.W. (2010b). Recurrent circulatory stress: The dark side of dialysis. Seminars in Dialysis, 23(5), 449451. doi:10.1111/j.1525-139X.2010. 00782.x McIntyre, C.W., Harrison, L., Eldehni, M., Jefferies, H., Szeto, C., John, S. G., ... Li, P. (2011). Circulating endotoxemia: A novel factor in systemic inflammation and cardiovascular disease in chronic kidney disease. Clinical Journal of American Society of Nephrology, 6, 133-141. National Health and Medical Research Council. (2007). National Statement on Ethical Conduct in Human Research (2007 – Updated May 2013). Canberra: Commonwealth of Australia. National Kidney Foundation (NKF). (2005). KDOQI clinical practice guidelines for cardiovascular disease in dialysis patients. American Journal of Kidney Diseases, 45(4, Suppl. 3), S1154. National Kidney Foundation (NKF). (2006). KDOQI clinical practice guidelines and clinical practice recommendations for 2006 updates: Hemodialysis adequacy, peritoneal dialysis adequacy and vascular access. American Journal of Kidney Diseases, 48(Suppl. 1), S1-S322. Nesralla, G., Suri, R., Guyatt, G., Mustafa, R., Walter, S., Lindsay, R.M., & Akl, E. (2013). Biofeedback dialysis for hypotension and hypervolemia: A systemic review and meta-analysis. Nephrology Dialysis and Transplantation (28), 182-191. doi:10.1093/ndt/gfs389 Ok, E., Asci, G., Toz, H., Ok, E. S., Kircelli, F., Yilmaz, M., ... Ozkahya, M. (2013). Mortality and cardiovascular events in online haemodiafiltration (OL-HDF) compared with highflux dialysis: Results from the Turkish OL-HDF Study. Nephrology Dialysis and Transplantation, 28(1), 192-202. doi:10.1093/ndt/gfs407

166

Palmer, B.F. (2009). Preventing intradialytic hypotension. Seminars in Dialysis, 22(5), 489-491. doi:10.1111/j. 1525-139X.2009.00643.x Palmer, B.F., & Henrich, W.L. (2008). Recent advances in the prevention and management of intradialytic hypotension. Journal of the American Society of Nephrology, 19(1), 8-11. doi:10.1681/ASN.2007091006 Quader, M., Kumar, D., Shah, K., Fatani, Y., Katlaps, G., & Kasirajan, V. (2014). Safety analysis of intermittent hemodialysis in patients with continuous flow left ventricular assist devices. Hemodialysis International, 18(1), 205-209. doi:10.111/hdi.12073 Rew, L., & Barrow, E. (1987). Intuition: A neglected hallmark of nursing knowledge. Advances in Nursing Science, 10(1), 49-61. doi:10.1097/00012272198710000-00010 Saran, R., Bragg-Gresham, J.L., Levin, N.W., Twardowski, Z.J., Wizemann, V., Saito, A., ... Port, F.K. (2006). Longer treatment time and slower ultrafiltration in hemodialysis: Associations with reduced mortality in the DOPPS. Kidney International, 69(7), 1222-1228. doi:10.1038/sj.ki.5000186 Schreiber, Jr., M.J. (2001). Setting the stage. American Journal of Kidney Diseases, 38(4, Supplement 4), S1-S10. doi:10.1053/ajkd.2001.28089 Sherman, R. (1988). The pathophysiologic basis for hemodialysis related hypotension. Seminars in Dialysis, 1(2), 136-142. doi:10.1111/j.1525139X.1988.tb00747.x Sherman, R., & Kapoian, T. (2011). Intradialytic hypotension strikes again. Journal of the American Society of Nephrology, 22(8), 1396-1398. doi:10.1681/ ASN.2011060541 Shinzato, T., Miwa, M., Nakai, S., Morita, H., Odani, H., Inoue, I., & Maeda, K. (1994). Role of adenosine in dialysisinduced hypotension. Journal of the American Society of Nephrology, 4(12), 1987-1994. Shoji, T., Tsubakihara, Y., Fujii, M., & Imai, E. (2004). Hemodialysis-associated hypotension is an independent risk factor for two-year mortality in hemodialysis patients. Kidney International, 66(3), 1212-1220. doi:10. 1111/j.1523-1755.2004.00812.x

Stafie, M.-E., Checherit , I.A., Niculae, A., Lupu oru, G., David, C., & Ciocâlteu, A. (2010). Intradialytic hypotension: Mechanisms and therapeutic implications. Therapeutics, Pharmacology & Clinical Toxicology, 14(1), 57-62. Stiller, S., Bonnie-Schoren, E., Grassmann, A., Uhlenusch-Korwer, I., & Mann, H. (2001). A critical review of sodium profiling for hemodialysis. Seminars in Dialysis, 14(5), 337-347. doi:10. 1046/j.1525-139X.2001.00086.x Sudsawad, P. (2007). Knowledge translation: Introduction to models, strategies and measures. Austin, TX: Southwest Educational Development Laboratory, National Center for the Dissemination of Disability Research. Sulowicz, W., & Radziszewski, A. (2006). Pathogenesis and treatment of dialysis hypotension. Kidney International, 70(S104), S36-S39. doi:10.1038/sj.ki. 5001975 Thijssen, S., Kappel, F., & Kotanko, P. (2013). Absolute blood volume in hemodialysis patients: Why is it relevant, and how to measure it? Blood Purification(35), 63-71. doi: 10.1159/ 000345484 Tomita, M., Malhotra, D., Dheenan, S., Shapiro, J.I., Henrich, W.L., & Santoro, T.J. (2001). A potential role for immune activation in hemodialysis hypotension. Renal Failure, 23(5), 637-649. doi:10.1081/JDI-100107360 Trivedi, H., Kukla, A., Prowant, B., & Lim, H. (2007). A study of the extracorporeal rate of blood flow and blood pressure during hemodialysis. Hemodialysis International, 11(4), 424429. doi:10.1111/j.1542-4758.2007. 00212.x van der Sande, F., Kooman, J., & Leunissen, K. (2000). Intradialytic hypotension – New concepts on an old problem. Nephrology Dialysis and Transplantation, 15(11), 1746-1748. doi:10.1093/ndt/15.11.1746 Yung, J. (2008). Optimal ultrafiltration profiling in hemodialysis. Nephrology Nursing Journal, 35(3), 287-289. Zoccali, C. (2003). Arterial pressure components and cardiovascular risk in end-stage renal disease. Nephrology Dialysis and Transplantation, 18(2), 249-252. doi:10.1093/ndt/18.2.249


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