End‐expiratory lung volume assessment using helium and carbon dioxide in an experimental model of pediatric capnoperitoneum

Background Capnoperitoneum during laparoscopy leads to cranial shift of the diaphragm, loss in lung volume, and risk of impaired gas exchange. Infants are susceptible to these changes and bedside assessment of lung volume during laparoscopy might assist with optimizing the ventilation. Thus, the primary aim was to investigate the monitoring value of a continuous end‐expiratory lung volume (EELV) assessment method based on CO2 dynamics ( EELVCO2) in a pediatric capnoperitoneum model by evaluating the correlation and trending ability against helium washout (EELVHe). Methods Intra‐abdominal pressure (IAP) was randomly varied between 0, 6, and 12 mm Hg with CO2 insufflation, while positive end‐expiratory pressure (PEEP) levels of 3, 6, and 9 cm H2O were randomly applied in eight anesthetized and mechanically ventilated chinchilla rabbits. Concomitant EELVCO2 and EELVHe and lung clearance index (LCI) were obtained under each experimental condition. Results Significant correlations were found between EELVCO2 and EELVHe before capnoperitoneum (r = .85, P