Studying the arterial to end-tidal carbon dioxide difference in children undergoing laparoscopic surgeries under different intra-abdominal pressures is of extreme importance. This is because both hyper and hypocarbia are detrimental in this vulnerable age group.

Capnography provides a non-invasive estimate of arterial CO2 levels and allows clinicians to modify mechanical ventilation settings in order to maintain normocapnia. Normally, a positive gap between arterial CO2 and ETCO2 of approximately 0.5 kPa is assumed in a healthy patient and ventilation settings are adjusted accordingly. However, the correlation between PaCO2 and PetCO2 during laparoscopic surgery is inconsistent mainly due to inter- and intra-individual variability. Discrepancies between arterial carbon dioxide and End-tidal carbon dioxide measures have been demonstrated in ventilated children with cyanotic congenital heart disease , infants with respiratory failure and during visceral and urological laparoscopic surgery. Moreover, as the increase in PaCO2 is directly proportional to the level of intra-abdominal pressure (IAP) used, variations in the arterial to end-tidal carbon dioxide difference can be also expected with different levels of IAP used.

Inclusion Criteria:

• Children with the following inclusion criteria;
• Weight: 10-30 kg.
• Age: 1-6 years.
• Sex: both males and females.
• ASA physical status: I, II.
• Operation: elective laparoscopic surgeries that last more than 45 min.

Exclusion Criteria:

Patients will be excluded if they have;

• Patients with any perioperative cardiovascular or respiratory event occurred which made the study intervention clinically unacceptable,
• Patients with unsatisfactory preoperative peripheral arterial oxygen saturation,
• Patients with unsatisfactory preoperative hemoglobin level, neurological or psychiatric disease,
• Children with a BMI >95th percentile for age.

Children scheduled for laparoscopic surgery of Weight: 10-30 kg, Age: 1-6 years, both males and females,ASA physical status: I, II.