Heated Irrigation Fluids Did Not Reduce the Prevalence of Rectally Measured Hypothermia During Hip Arthroscopic Surgery Compared With Room-Temperature Fluids: A Prospective Randomized Trial.

Background: Close monitoring and heated irrigation fluids have been frequently used to avoid hypothermia and associated complications during hip arthroscopic surgery. Saline fluids are used extensively in hip arthroscopic surgery, but they are routinely stored at room temperature and are cooler than the patient's core temperature.

Purpose: To investigate the efficacy of heated irrigation fluids to prevent hypothermia during hip arthroscopic surgery and whether the core temperature measured rectally during hip arthroscopic surgery differs from the core temperature measured at the temporal region.

Study design: Randomized controlled trial; Level of evidence, 2.

Methods: Patients who underwent hip arthroscopic surgery for the treatment of femoroacetabular impingement syndrome between 2021 and 2023 were prospectively enrolled and divided into 2 groups: those whose irrigation fluids were stored at room temperature (group 1) and those whose irrigation fluids were heated to 36°C to 38°C (group 2). A probe inserted in the rectal mucosa was used to measure the patient's body temperature every 15 minutes. The patient's temperature was also measured at the temporal region with a laser thermometer. A body temperature <36°C, detected by either method, was considered as hypothermia. The method that detected hypothermia more quickly was investigated, and the effect of the heated irrigation fluids was explored. Statistical analyses were conducted to compare temperature measurements and the incidence of hypothermia between the groups using appropriate tests for categorical and continuous variables based on the data distribution.

Results: There were 60 patients randomized and allocated to group 1 and 56 patients to group 2. Hypothermia, defined as a temperature <36°C, occurred in 32 patients (53.3%) in group 1 and 24 patients (42.9%) in group 2. There was no difference between the groups using heated or room-temperature fluids in the onset of hypothermia (P = .425). Significantly more hypothermia cases were detected by the rectal temperature measurement than by the temporal temperature measurement (54 vs 2 patients, respectively; P < .001). The rectal temperature measurement was also quicker in detecting hypothermia (69.6 ± 47.2 vs 138.2 ± 56.8 minutes, respectively; P < .001).

Conclusion: This study demonstrates that the usage of either room-temperature or heated irrigation fluids did not influence the incidence of hypothermia. Rectal measurements of core body temperature detected hypothermia earlier during hip arthroscopic surgery.

Registration: NCT05396924 (ClinicalTrials.gov).