Cryotherapy for Reducing Fistula Puncture Pain in Hemodialysis Patients (CRYO-AVF)

Background: Patients undergoing chronic hemodialysis require repeated arteriovenous fistula (AVF) cannulation, typically three times per week, resulting in over 300 needle punctures per year. Puncture-related pain and anxiety are common and can contribute to treatment avoidance and reduced quality of life. Cryotherapy has been proposed in prior literature as a simple, inexpensive, non-pharmacological method to reduce puncture-related pain by slowing nerve conduction velocity, but its comparative effectiveness against topical anesthetic gel and usual care has not been well established in clinical practice.

Objective: To compare the effectiveness of cryotherapy, topical lidocaine/prilocaine gel, and usual care in reducing AVF puncture-related pain and anxiety among hemodialysis patients, and to evaluate their effects on quality of life and physiological stress response.

Design: This is a randomized controlled trial with three parallel arms. Eligible participants were randomly assigned by dice-roll allocation to one of three groups:

1. Usual care: application of a room-temperature water bag to the puncture site for 5 minutes before cannulation.
2. Cryotherapy: application of a 200g ice pack, wrapped in a single layer of cotton cloth, to the LI4 (Hegu) acupoint on the non-fistula hand for 5 minutes before cannulation.
3. Topical anesthetic: application of lidocaine/prilocaine gel to two puncture areas under an occlusive dressing for up to 1 hour before cannulation.

All participants underwent the same cannulation procedure performed by the same operator using a 16Fr fistula needle, over three consecutive dialysis sessions (three times per week). Outcome assessors collecting data were blinded to group assignment.

Outcome Measures: Pain and symptom distress were assessed using the Edmonton Symptom Assessment Scale-revised (ESAS-r, 10 items) at four time points (pre-puncture, post-puncture, during dialysis, post-dialysis) across all three sessions. Quality of life was assessed using the EQ-5D-5L before dialysis, after dialysis, and before the next dialysis session. Heart rate variability (HRV), as an objective marker of sympathetic nervous system activity, was measured at the same time points as the EQ-5D-5L. Vital signs, dialysis blood flow rate, and pre/post-dialysis body weight were also recorded.

Statistical Analysis: Descriptive statistics (means, standard deviations, frequencies, percentages) were used to summarize demographic and clinical characteristics. Between-group comparisons were conducted using t-tests, chi-square tests, and two-way ANOVA to evaluate the effects of the interventions on pain, anxiety, and quality-of-life outcomes.