Influence of Obesity on Microvascular Reactivity During General Anesthesia

Influence of Obesity on Microvascular Reactivity During General Anesthesia

The purpose of this study was to investigate the effect of obesity on changes in microvascular reactivity and tissue oxygen saturation (StO2) during general anesthesia using near-infrared spectroscopy in conjunction with vascular occlusion tests (VOT).

For this prospective observation investigation, a total of 128 patients who underwent elective surgery under general anesthesia at Pusan National University Hospital between June 2018 and February 2021 were participated in this study. Baseline StO2 on thenar eminence, hemodynamics, and laboratory profile were monitored before (Tpre) and 30 min after general anesthesia (Tpost). During vascular occlusion tests (VOT), the occlusion slope representing oxygen consumption of muscle and recovery slope representing microvascular reactivity were also collected at Tpre and Tpost. For analysis, the patients were divided into two groups: overweight (body mass index [BMI] ≥ 25 kg/m2) and normal weight (BMI < 25).

Preoperative laboratory findings were obtained. Mean blood pressure (MBP), pulse oxygen saturation (SpO2), heart rate (HR), skin temperature, and VOT-derived measurements, including baseline tissue oxygen saturation (StO2), occlusion slope, minimum StO2, time to minimum StO2, recovery slope, maximum StO2, and time to baseline StO2 were recorded before (Tpre) and 30 min after general anesthesia (Tpost).

Inclusion Criteria:

• Subjects who underwent elective surgery under general anesthesia.

Exclusion Criteria:

• Society of Anesthesiologists (ASA) physical status > II
• patients with a neuraxial block
• uncontrolled hypertension
• patients with major cardiovascular disease
• diabetes
• pregnant individuals
• peripheral vascular disease
• chronic venous insufficiency
• smoking: Pack-years > 10
• chronic obstructive and restrictive pulmonary disease