Optimal Frequency of Total Body Water Measurements by Bioelectrical Impedance Analysis to Prevent Intradialytic Hypotension

The study, conducted at Thammasat University Hospital, aimed to assess the efficacy of different frequencies of BIA measurements in preventing intradialytic hypotension in ESRD patients undergoing hemodialysis.

The trial enrolled ESRD patients and collected data from June 2022 to February 2023.

Research Procedure:

• Screening for eligibility was conducted among individuals undergoing hemodialysis at the hemodialysis unit of Thammasat University Hospital.
• Informed consent was obtained from participants or their authorized representatives.
• Basic demographic and medical data were recorded, including gender, age, pre-existing conditions, causes of kidney disease, smoking habits, regular medications. The dry weight, interdialytic weight gain (IDWG), and net ultrafiltration (UF) were calculated from every session of the patient's dialysis, and then taken the average. Blood flow rate (BFR) and dialysate temperature were taken from the largest value from each dialysis session and the greatest frequency. Single pool KT/V and blood tests (hemoglobin, serum albumin, electrolytes) were from the closest value before entering the research. Pre-dialysis systolic blood pressure (SBP) and diastolic blood pressure (DBP) were the average values.
• Volunteers were randomly assigned to two groups, each consisting of 45 individuals. Group 1 underwent BIA measurements monthly for 4 months, then switched to bi-monthly BIA measurements for 4 months. Group 2 underwent BIA measurements every 2 months for 4 months, then switched to monthly BIA measurements for 4 months. Data were used as a combination to adjust dry weight for accurate fluid removal.
• Episodes of intra-dialyltic hypotension were recorded and the numbers of such episodes were calculated as incidence rates to explore the most optimum frequency of BIA measurement (between every-1-month group and the every-2-month). Intradialytic hypotension in this study was defined as a decrease in (SBP) ≥ 20 mmHg or a decrease in mean arterial pressure (MAP) ≥ 10 mmHg. For BIA measurements in addition to the presence of intradialytic hypotension, the number of occurrences of intradialytic hypotension was counted as one increase.
• Factors affecting intradialytic hypotension were also explored.

Inclusion criteria

• over 18 years of age
• dialysis vintage ≥ 3 months
• hemodialysis at least thrice weekly
• hemodialysis ≥ 3 hours per session.

Exclusion criteria

• congestive heart failure (NYHA class 3-4)
• cardiac arrhythmias with relapse within 1 month and still unable to control symptoms during the drug adjustment period
• coronary artery disease which active within 1 month without treatment
• patients who take regular oral medications to raise blood pressure before undergoing dialysis such as midodrine
• patients with low blood pressure or requiring blood pressure medication adjustments within 1 month period
• has another unstable symptom