Effect of PEEP on Arterial Oxygen Partial Pressure in Elderly Patients With Lithotomy Position Using LMA Supreme™

Positive end-expiratory pressure (PEEP) during general anesthesia with mechanical ventilation is routinely used as a standard lung protective strategy to prevent postoperative pulmonary complications including atelectasis.

In urologic surgery, elderly patients are common. Since aging decreases the elasticity of lung tissues and allowing the collapse of small airways, old age is a risk factor for postoperative atelectasis. Lithotomy position is the preferred position in urologic surgery. However, it causes the abdominal viscera to displace the diaphragm cephalad, reducing lung compliance and resulting atelectasis. Therefore, in elderly patients undergoing urologic surgery with lithotomy position, PEEP may be essential to prevent postoperative atelectasis.

Laryngeal mask airway (LMA) has been widely used in urologic surgery with lithotomy position because of short surgical time and no necessity of administration of muscle relaxant. However, application of PEEP when using LMA is still controversy. Therefore, in the present study, we aimed to compare the effect of PEEP on arterial oxygen partial pressure in elderly patients undergoing urologic surgery using LMA supreme™ in a lithotomy position.

Inclusion criteria

• Patients undergoing urologic surgery with lithotomy position under general anesthesia
• Elderly patients (65 ≤ Age < 80)
• American Society of Anesthesiologists (ASA) physical status: 1-3
• Patients who voluntarily agreed to participate in this clinical study

Exclusion criteria

• Heart failure (ejection fraction ≤ 40%)
• Hemodynamic instability during perioperative period
• Lung diseases (chronic obstructive pulmonary disease, asthma, bullae, pleural effusion)
• Obesity (BMI ≥ 30 kg/m2)
• Neck or upper respiratory tract pathologies
• An increased risk of pulmonary aspiration
• Anticipation of the difficult laryngeal mask fixation due to poor dentition