Does the Laminar Airflow System Affect the Development of Perioperative Hypothermia? A Randomized Clinical Trial.

OBJECTIVES

We aimed to compare tympanic membrane temperature changes and the incidence of inadvertent perioperative hypothermia (IPH) in patients undergoing laparoscopic cholecystectomy under general anesthesia in laminar airflow systems (LAS-OR) and conventional turbulent airflow systems (CAS-OR).

BACKGROUND

Different heating, ventilation, and air-conditioning (HVAC) systems are used in the operating room (OR), such as LAS and CAS. Laminar airflow is directed directly to the patient in LAS-OR. Does laminar airflow in ORs cause faster heat loss by convection?

METHODS

This is a prospective, randomized study. We divided 200 patients with simple randomization (1:1), as group LAS and group CAS, and took the patients into the LAS-OR or CAS-OR for the operation. Clinical trial number: IRCT20180324039145N3. The tympanic membrane temperatures of patients were measured (°C) before anesthesia induction () and then every 15 min during surgery (). Changes (Δ) between and were measured.

RESULTS

In the first 30 min, there was a temperature decrease of approximately 0.8 °C (1.44 °F) in both groups. Temperature decreases at 45 min were higher in group LAS than in group CAS but not statistically significant, Δ, respectively, 0.89 (95% confidence interval [CI] [0.77, 1.02]) versus 0.77 (95% CI [0.69, 0.84]; = .09). IPH occurred in a total of 60.9% (112 of 184) of patients in the entire surgical evaluation period in group LAS and group CAS (58.9% vs. 62.8%, = . 59).

CONCLUSIONS

IPH is seen frequently in both HVAC systems. Clinically, the advantage of HVAC systems relative to each other has not been demonstrated during laparoscopic cholecystectomy.