Analysis of the incidence and related factors of hypothermia in patients with continuous renal replacement therapy

Abstract

To investigate the incidence and risk factors of hypothermia in patients with acute renal injury (AKI) receiving continuous renal replacement therapy (CRRT), and to compare the effects of different heating methods on the incidence of hypothermia in patients with CRRT. A prospective study was conducted. AKI patients with CRRT who were admitted to the department of critical care medicine of the First Affiliated Hospital of Wannan Medical College (Yijishan Hospital) from January 2020 to December 2022 were enrolled as the study subjects. Patients were divided into dialysate heating group and reverse-piped heating group according to randomized numerical table method. Both groups were provided with reasonable treatment mode and parameter setting by the bedside physician according to the patient's specific condition. The dialysis heating group used the AsahiKASEI dialysis machine heating panel to heat the dialysis solution at 37 centigrade. The reverse-piped heating group used the Barkey blood heater from the Prismaflex CRRT system to heat the dialysis solution, and the heating line temperature was set at 41 centigrade. The patient's temperature was then continuously monitored. Hypothermia was defined as a temperature lower than 36 centigrade or a drop of more than 1 centigrade from the basal body temperature. The incidence and duration of hypothermia were compared between the two groups. Binary multivariate Logistic regression analysis was used to explore the influencing factors of hypothermia during CRRT in AKI patients. A total of 73 patients with AKI treated with CRRT were eventually enrolled, including 37 in the dialysate heating group and 36 in the reverse-piped heating group. The incidence of hypothermia in the dialysis heating group was significantly lower than that in the reverse-piped heating group [40.5% (15/37) vs. 69.4% (25/36), P < 0.05], and the hypothermia occurred later than that in the reverse-piped heating group (hours: 5.40±0.92 vs. 3.35±0.92, P < 0.01). Patients were divided into hypothermic and non-hypothermic groups based on the presence or absence of hypothermia, and a univariate analysis of all indicators showed a significant decrease in mean arterial pressure (MAP) in hypothermic patients (n = 40) compared with the non-hypothermic patients [n = 33; mmHg (1 mmHg ≈ 0.133 kPa): 77.45±12.47 vs. 94.42±14.51, P < 0.01], shock, administration of medium and high doses of vasoactive drug (medium dose: 0.2-0.5 μg×kg-1×min-1, high dose: > 0.5 μg×kg-1×min-1) and CRRT treatment were significantly increased [shock: 45.0% (18/40) vs. 6.1% (2/33), administration of medium and high doses of vasoactive drugs: 82.5% (33/40) vs. 18.2% (6/33), administration of CRRT (mL×kg-1×h-1): 51.50±9.38 vs. 38.42±10.97, all P < 0.05], there were also significant differences in CRRT heating types between the two groups [in the hypothermia group, the main heating method was the infusion line heating, which was 62.5% (25/40), while in the non-hypothermia group, the main heating method was the dialysate heating, which was 66.7% (22/33), P < 0.05]. Including the above indicators in a binary multivariate Logistic regression analysis, it was found that shock [odds ratio (OR) = 17.633, 95% confidence interval (95%CI) was 1.487-209.064], mid-to-high-dose vasoactive drug (OR = 24.320, 95%CI was 3.076-192.294), CRRT heating type (reverse-piped heating; OR = 13.316, 95%CI was 1.485-119.377), and CRRT treatment dose (OR = 1.130, 95%CI was 1.020-1.251) were risk factors for hypothermia during CRRT in AKI patients (all P < 0.05), while MAP was protective factor (OR = 0.922, 95%CI was 0.861-0.987, P < 0.05). AKI patients have a high incidence of hypothermia during CRRT treatment, and the incidence of hypothermia can be effectively reduced by heating CRRT treatment fluids. Shock, use of medium and high doses of vasoactive drug, CRRT heating type, and CRRT treatment dose are risk factors for hypothermia during CRRT in AKI patients, with MAP is a protective factor.