Are Operating Rooms With Laminar Airflow a Risk for Inadvertent Perioperative Hypothermia During Ureterorenoscopic Lithotripsy Under Spinal Anesthesia? A Prospective Randomized Clinical Trial.

Abstract

Inadvertent perioperative hypothermia (IPH), defined as a core temperature <36°C, is common during a surgical procedure and is associated with high morbidity and mortality. Laminar (LAS) and conventional airflow systems (CAS) are used frequently for clean microenvironmental surgical areas in operating rooms. In LAS, the cold airflow is directed toward the patient, unlike CAS. Does this airflow in LAS cause heat loss from the patient by convection more than CAS? We aimed to compare the IPH frequencies of these airflow systems on patients who underwent ureterorenoscopic lithotripsy (ureterorenoscopic surgery) under spinal anesthesia. The study was a prospective, parallel-group, randomized trial. A total of 246 volunteers were included in the study and divided into group LAS (n = 123) and group CAS (n = 123). Randomization of patients was performed using the closed-envelope method (as 1:1).The tympanic membrane temperature of patients was measured before spinal anesthesia ( T0 ) and then every 15 minutes ( T n ) during the procedure. The IPH ratio and the change of the tympanic temperatures (Δ T ) were recorded (clinical trial number: IRCT20180324039145N5). In total, there were no statistical differences between the IPH ratios of group LAS and group CAS (61.2% [71 of 116] versus 49.6% [57 of 115], respectively; P = 0.075). The IPH ratio was 55.4% (128 of 231). The tympanic temperatures of patients decreased about 0.64°C (0.45°C) at the 30th minute. In both groups, Δ 30 was similar (0.62; 95% confidence interval, 0.52-0.72 [ P = 0.65]; 95% confidence interval, 0.55-0.74 [ P = 0.236], respectively). The risk for IPH of both LAS and CAS in the operating room is similar during ureterorenoscopic surgery.