Heated Circuit for One-lung Ventilation

Effect of Heated-humidified Circuit on Arterial Oxygenation in Patients Undergoing One-lung Ventilation for Thoracoscopic Surgery

One-lung ventilation interrupts oxygenation. The effect of heated humidifed breathing circuit on arterial oxygenation during one-lung ventilation has not been investigated. The investigators will investigate the effect of the heated humidifed breathing circuit on oxygenation during one-lung ventilation in patients undergoing thoracoscopic surgery.

Inclusion Criteria:

• American Society of Anesthesiologist class I-II
• Patients scheduled for one-lung ventilation for thoracoscopic surgery

Exclusion Criteria:

• Obesity
• Severe obstructive or restrictive lung disease
• Preoperative oxygen supply
• Preoperative intubated state or under mechanical ventilatory support
• Baseline arterial partial pressure of oxygen (PaO2) < 70 mmHg
• Symptomatic coronary or peripheral arterial disease
• Renal failure
• Preoperative continuous infusion of inotropes or vasopressor
• Pregnancy