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

Study Overview
=================
Brief Summary
-----------------
The purpose of the present study is to compare the effect of PEEP on arterial oxygen partial pressure in elderly patients undergoing urologic surgery using LMA supreme™ in a lithotomy position.

Detailed Description
-----------------
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.

Official Title
-----------------
Effect of Positive End-expiratory Pressure on Arterial Oxygen Partial Pressure in Elderly Patients Undergoing Urologic Surgery Using LMA Supreme™ in Lithotomy Position

Conditions
-----------------
Urinary Bladder Neoplasms, Prostatic Neoplasms

Intervention / Treatment
-----------------
* Other: PEEP


Participation Criteria
=================
Eligibility Criteria
-----------------
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

Ages Eligible for Study
-----------------
Minimum Age: 65 Years
Maximum Age: 79 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group P<br>After LMA Supreme™ insertion, PEEP of 7 cmH2O would apply during general anesthesia with mechanical ventilation. | Other: PEEP<br>* After LMA Supreme™ insertion, it's proper position is confirmed. Then, PEEP of 7 cmH2O is applied during mechanical ventilation.<br>* Other names: Application of PEEP 7 cmH2O;|
| No Intervention: Group Z<br>After LMA Supreme™ insertion, PEEP would not apply during general anesthesia with mechanical ventilation. | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The difference of arterial oxygen partial pressure (PaO2) between group P and group Z | The difference of arterial oxygen partial pressure (PaO2) between group P and group Z 1 hour after LMA insertion by arterial blood gas analysis | 1 hour after LMA insertion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative pulmonary complications | Postoperative pulmonary complications include atelectasis, pneumothorax, bronchospasm, pneumonia, pulmonary edema, pleural effusion, respiratory failure | Up to seven days | 
| Complications associated with LMA | Complications associated with LMA include oropharyngolaryngeal injury and sore throat. | 1 hour after end of surgery | 
| Incidence of significant leak of LMA | Significant leak of LMA means that leak friction is more than 0.2. | At 5, 30, 60 mins after LMA insertion | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
elderly, lithotomy position, PEEP, laryngeal mask airway