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 (EELV CO2) in a pediatric capnoperitoneum model by evaluating the correlation and trending ability against helium washout (EELVHe).