Impact of Obesity, Respiratory Symptoms, and Posture on Perioperative Respiratory Adverse Events and Lung Function in Children.

Abstract

Obesity is linked to altered lung function and increased perioperative respiratory adverse events (PRAEs). We examined the effects of obesity, respiratory symptoms, and posture on PRAEs, lung mechanics, and ventilation distribution in children undergoing general anesthesia. A total of 110 children (6-16 years) undergoing elective surgery were stratified into normal-weight and overweight/obese groups. Preoperative respiratory symptoms were documented. Respiratory mechanics and end-expiratory lung volume were assessed by forced oscillation technique (FOT) and multiple-breath nitrogen washout (MBW), respectively, in sitting and supine positions before anesthesia induction; FOT was repeated after induction. All PRAEs were recorded. Severe PRAEs were uncommon (5/110, 4.5%, (95% confidence interval [CI], 1.5%-10.4%) laryngospasm; no bronchospasm). Minor PRAE occurred more frequently in obese children compared with normal-weight children (19/55, 34.5% (95% CI, 22.2%-48.6%) vs 9/55, 16.4% (95% CI, 7.9%-28.3%)), regardless of respiratory symptoms. Obesity was associated with increased peripheral airway resistance, most evident in the supine and anesthetized states. Respiratory symptoms primarily affected tissue mechanics, and additive impairments were observed when children were overweight/obese and had respiratory symptoms. MBW outcomes showed minimal group differences, though supine positioning consistently reduced functional residual capacity and increased lung clearance index. Anesthesia induction led to reduced resistance and improved elasticity, likely reflecting anesthesia-induced bronchodilation, but this effect was attenuated in obese children and those with respiratory symptoms. Obesity increased susceptibility to minor PRAE and elevated peripheral airway resistance, whereas respiratory symptoms impaired tissue mechanics. Postural change exerted a dominant influence on lung function. Anesthesia-induced bronchodilatation was blunted in obese children and those with respiratory symptoms, highlighting the need for targeted perioperative strategies.