Intradialytic Hypotension: A New Insight to an Old Problem

Effect of Intradialytic Aerobic Exercise on Relative Blood Volume in Patients Undergoing Maintenance Hemodialysis

The purpose of this study was to investigate changes in the relative blood volume because of intradialytic exercise. Twenty patients undergoing hemodialysis (HD) were assigned randomly to exercise or control sessions as a first test by simple randomization. All participants were crossed over and participated in both tests. In the exercise test, each patient underwent 30 minutes of exercise using a cycle ergometer from the initiation of HD. The control session consisted of routine HD without exercise. The blood volume (ΔBV) reduction in both types of sessions was calculated from the area under the curve of the ΔBV (ΔBVAUC) from the initiation of HD to the end of exercise (During Ex), from the end of exercise to the end of HD (Post Ex), and during the entire HD session (Whole HD). The ΔBVAUC of Post Ex in the exercise test (44.9 ± 14.3%h) was significantly smaller than that in the control test (50.3 ± 14.3%h) (p < 0.05), although other parameters such as ΔBVAUC either in the entire HD session or during exercise training did not differ significantly between two groups. This result suggests that intradialytic exercise at the beginning of the HD sessions may be altered the ΔBV in the latter part of the session.

Relationship between blood pressure response during hemodialysis and exercise tolerance or heart rate recovery measured using cardio-pulmonary exercise testing in maintenance hemodialysis patients

Background

This study investigated the association between the blood pressure response during hemodialysis (HD) and exercise tolerance or heart rate recovery (HRR) measured with cardiopulmonary exercise testing (CPX).

Methods

The study enrolled 23 patients who had been undergoing 4-h regular maintenance HD. The maximum workload (Loadpeak), peak oxygen uptake (VO2peak), workload and oxygen uptake at the anaerobic threshold (LoadAT and VO2AT, respectively), and HRR were measured with CPX. The average systolic blood pressure during HD (SBPav) was measured, and the number of times the SBP was less than 100 mmHg was determined in the 2-week period after CPX.

Results

The SBPav showed a significant correlation with LoadAT (r = 0.46) and Loadpeak (r = 0.43, p < 0.05). The number of times the SBP was less than 100 mmHg showed a significant correlation with the HRR (r = − 0.44, p < 0.05).

Conclusion

Exercise intolerance and HRR in HD patients may be associated with blood pressure instability during HD.

Relative blood volume changes during haemodialysis estimated from haemoconcentration markers

Relative blood volume (RBV) monitoring is frequently used in haemodialysis patients to help guide fluid management and improve cardiovascular stability. RBV changes are typically estimated based on online measurements of certain haemoconcentration markers, such as haematocrit (HCT), haemoglobin (HGB) or total blood protein concentration (TBP). The beginning of a haemodialysis procedure, i.e. filling the extracorporeal circuit with the patient’s blood (with the priming saline being infused to the patient or discarded) may be associated with relatively dynamic changes in the circulation, and hence the observed RBV changes may depend on the exact moment of starting the measurements. The aim of this study was to use a mathematical model to assess this issue quantitatively. The model-based simulations indicate that when the priming saline is not discarded but infused to the patient, a few-minute difference in the moment of starting RBV tracking through measurements of HCT, HGB or TBP may substantially affect the RBV changes observed throughout the dialysis session, especially with large priming volumes. A possible overestimation of the actual RBV changes is the highest when the measurements are started within a couple of minutes after the infusion of priming saline is completed.

Clinical research on individualized hemodialysis preventing unconventional hypotension in diabetic nephropathy patient

OBJECTIVE

This study aims to evaluate the effectiveness of individualized hemodialysis for unconventional hypotension in diabetic nephropathy patients.

METHODS

A total of 60 patients were selected and randomly divided into study group and control group. The control group used the standard dialysis model, while the study group used the individualized hemodialysis scheme, in which the dialysis was performed using an individualized dialysis machine temperature control, pattern of natrium, and pattern of step ultrafiltration in combination with dialysate-containing glucose.

RESULTS

The total occurrence rate of hypotension, dry weight standard-reaching rate, and blood quality during and after dialysis in the study group were superior to those in the control group (P < 0.05). Furthermore, the symptom scores in the study group (dizziness score, chest distress score, sweating score, muscle spasm score, gastrointestinal symptom score, and temporary mind change score) were lower than those in the control group (P < 0.05). The serum sodium, potassium, and chloride concentration in these two groups after dialysis was not statistically different (P > 0.05).

CONCLUSION

The combined application of low temperature, pattern of natrium, pattern of step ultrafiltration, and dialysate-containing glucose individualization is safe and effective for preventing and controlling the occurrence of intradialytic hypotension (IDH), improve symptoms, and improve the dry weight standard-reaching rate.

Intradialytic Hypotension as an Independent Risk Factor for Long-Term Mortality in Maintaining Hemodialysis Patients: A 5-Year Follow-Up Cohort Study

AIMS

This study aimed to assess risk factors of intradialytic hypotension (IDH) and the association of prognosis and IDH among maintenance hemodialysis (MHD) patients.

METHODS

Among 293 patients, 117 were identified with IDH (more than 4 hypotensive events during 3 months). The association between IDH and survival was evaluated.

RESULTS

The incidence of IDH was 39.9%. Age, ultrafiltration rate, N-terminal pro-B-type natriuretic peptide (NT-proBNP), albumin, β2-microglobulin (β2MG), and aortic root inside diameter (AoRD) were independently associated with IDH. During the 5-year follow-up, 84 patients died with a mortality rate 5.2 per 100 person-year. IDH-prone patients had a higher all-cause mortality rate. IDH and left ventricular mass index were independent risk factors for death (HR 1.655, 95% CI 1.061-2.580; HR 1.008, 95% CI 1.001-1.016).

CONCLUSION

IDH is an independent risk factor for long-term mortality in MHD patients. Patients with older age, high ultrafiltration rate, high level of serum NT-proBNP and β2MG, hypoalbuminemia, and shorter AoRD are at high risk of IDH.

Diuretics, Limited Ultrafiltration, and Residual Renal Function in Incident Hemodialysis Patients: A Case Series

The effect of diuretics on residual renal function expressed as residual GFR (rGFR) and urine volume (rUV) using 24-hour urine collections has not been well examined in hemodialysis (HD) patients. We present a small (seven patient) but provocative case series describing a strikingly low rate of decline in rUV and rGFR (average of creatinine and urea clearances, 24-hour urine collections) in patients treated with increasing doses of furosemide (up to 360 mg/day) during the first 2 years after initiation of HD. Between 6 and 12 months, the mean rUV fell by 1 ml/month, whereas rGFR declined by 0.03 ml/min/1.73 m(2) /month. The mean rate of decline from 12 to 24 months for rUV (33 ml/month) and rGFR (0.02 ml/min/1.73 m(2) /month) were also low. While data are clearly limited and the observation retrospective, they are consistent with the better documented benefit of diuretics observed in end-stage renal disease patients treated with peritoneal dialysis.

Noninvasive techniques for prevention of intradialytic hypotension

Episodes of hypotension during hemodialysis treatment constitutes an important clinical problem which has received considerable attention in recent years. Despite the fact that numerous approaches to reducing the frequency of intradialytic hypotension (IDH) have been proposed and evaluated, the problem has not yet found a definitive solution--an observation which, in particular, applies to episodes of acute, symptomatic hypotension. This overview covers recent advances in methodology for predicting and preventing IDH. Following a brief overview of well-established hypotension-related variables, including blood pressure, blood temperature, relative blood volume, and bioimpedance, special attention is given to electrocardiographic and photoplethysmographic (PPG) variables and their significance for IDH prediction. It is concluded that cardiovascular variables which reflect heart rate variability, heart rate turbulence, and baroreflex sensitivity are important to explore in feedback control hemodialysis systems so as to improve their performance. The analysis of hemodialysis-related changes in PPG pulse wave properties hold considerable promise for improving prediction.

Impact of blood volume monitoring on fluid removal during intermittent hemodialysis of critically ill children with acute kidney injury

BACKGROUND

In chronic pediatric patients treated with intermittent hemodialysis (IHD), blood volume monitoring (BVM) is commonly used to assess and manage volume status during the dialysis session. Minimal data exists on its use during IHD in critically ill children with acute kidney injury (AKI). In these cases, fluid removal may be limited by hemodynamic instability.

METHODS

We present a retrospective study conducted in our pediatric intensive care unit. For eligible patients, demographic data and IHD treatment characteristics were recorded including BVM use, ultrafiltration (UF) volume per session, hypotensive episodes and intradialysis interventions. Hypotensive episodes and UF per IHD session were compared between IHD sessions with BVM (BVM group) and IHD sessions without BVM (control group).

RESULTS

Twenty-three AKI patients with a median age of 11 years (1.8-18) and body weight of 36 kg (10-85) received 134 IHD sessions (70 with BVM and 64 without BVM). Hypotensive episodes occurred in 34% of all sessions with no significant difference between the BVM group and the control group: (95% CI: 22%, 44%) and 36% (95% CI: 24%, 48%), respectively, but UF per session was higher in the BVM group as compared to control (48 ± 27 mL/kg and 33 ± 26 mL/kg, respectively, P = 0.0001). The mean decrease in BVM did not exceed 13% over an entire dialysis session in patients without hypotension.

CONCLUSION

In conclusion, in our experience of IHD sessions in critically ill children with AKI, the use of BVM allowed a higher UF in those with BVM without influencing the frequency of hypotensive episodes. Applying specific guidelines on BVM use may decrease hypotensive episodes during IHD treatment in critically ill patients.