Impaired Capillary Recruitment Capacity in Obesity: A Subgroup Analysis of Prospective Observational Study on Anesthesia Effects

Abstract

Background: This subgroup analysis of prospective observational research, involving 71 participants, compared the effects of anesthesia on microvascular reactivity in obese vs lean individuals using near-infrared spectroscopy and vascular occlusion tests. The correlation between the body mass index (BMI) and microvascular reactivity under general anesthesia was also investigated. Material/Methods: This study enrolled adult patients classified as American Society of Anesthesiologists physical status I or II, undergoing elective surgery under general anesthesia. The microcirculatory variables measured before (Tpre) and 30 min following the induction of anesthesia (Tpost) were as follows: baseline tissue oxygen saturation (StO2), occlusion slope (Ñoccl), and recovery slope (Ñrecov). The patients were grouped according to their BMI (lean [BMI <25 kg/m2] vs obese [BMI 325 kg/m2]). Data are presented as medians and interquartile ranges. Results: There were 43 patients in the lean group and 28 in the obese group. At Tpre, baseline StO2, Ñoccl, and Ñrecov were not different between the 2 groups (P=0.860, 0.659, and 0.518, respectively). At Tpost, the baseline StO2 and Ñoccl were not different between the 2 groups (P=0.343 and 0.791); however, the Ñrecov was lower in the obese group than in the lean group (3.245 [2.737, 3.977] vs 4.131 [3.491, 4.843], P=0.003). At Tpost, BMI showed a moderate correlation with Ñrecov (correlation coefficient: -0.319, P=0.007). Conclusions: In obese patients, capillary recruitment capacity during general anesthesia is compromised compared to lean patients.