Obese patients require higher, but not high pneumatic tourniquet inflation pressures using a novel technique during total knee arthroplasty.

Abstract

This study aims to investigate the effect of obesity on pneumatic tourniquet inflation pressures determined with a novel formula during total knee arthroplasty (TKA). Data of 208 patients (19 males, 199 females; mean age 69.8 years; range, 53 to 84 years) who were performed TKA between January 2013 and December 2016 were evaluated prospectively. Patients were divided into two groups as non-obese (body mass index [BMI] ≤30.0 kg/m2) and obese (BMI >30.0 kg/m2) according to BMI. Tourniquet inflation pressures were set using arterial occlusion pressure (AOP) estimation method and adding 20 mmHg of safety margin to AOP value. All patients were assessed intra- and postoperatively with outcome measures such as systolic blood pressure, AOP, tourniquet pressure and its effectiveness. The quality of the surgical field and complications were assessed by the surgical team in a blinded fashion. The study included 118 and 90 lower extremity operations in obese and non-obese groups, respectively. Compared to non-obese group; extremity circumference, initial and maximal systolic blood pressures, AOP values, initial and maximal tourniquet pressures were higher in obese group. The performance of the tourniquet was assessed as "excellent" and "good" at almost all stages of the surgical procedure in all patients in both groups. No complication occurred intra- or postoperatively. Compared to non-obese patients, higher tourniquet inflation pressure is required in obese patients during TKA due to their wider extremity circumference and higher systolic blood pressure profile.