Recovery of Ventilation After Anesthesia for Laparoscopic Nephrectomy

Study Overview
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Brief Summary
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The purpose of this randomized, controlled feasibility investigation is to characterize pharmacologically induced ventilatory depression after anesthesia and examine how is affected by the amount of supplemental oxygen patients are receiving in the immediate postoperative period.

Detailed Description
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The purpose of this study is characterize pharmacologically induced ventilatory depression after anesthesia and examine how is affected by the amount of supplemental oxygen patients are receiving in the immediate postoperative period, since hyperoxemia (ie., higher than necessary partial pressure of oxygen in the arterial blood) has been associated with ventilatory depression via suppression of the hypoxic ventilatory drive. In this feasibility randomized controlled trial, the investigators plan to estimate and compare the cumulative segment of time during which the transcutaneous partial pressure of carbon dioxide will exceed an upper limit of 45 mmHg (i.e., TcPCO2 > 45 mmHg) for the 90-min-long post-anesthesia period, between the conventional (titrated to an oxygen saturation > 96%) and the conservative (titrated to O2 saturation 90 -94%) O2 supplementation interventions. Hypothesis: Conservative use of O2 (titrated to an SpO2: 90 - 94%), will be associated with less hypoventilation (i.e., less time spent with an TcPCO2 > 45 mmHg) during recovery from general anesthesia, compared to liberal O2 supplementation (SpO2 > 96%).

Official Title
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Recovery of Ventilation After General Anesthesia for Robotic-assisted Laparoscopic Nephrectomy: The Effect of Conservative Versus Liberal Oxygen Supplementation - A Feasibility Study

Conditions
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Ventilatory Depression, Postoperative Respiratory Complication

Intervention / Treatment
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* Other: Oxygen gas -Conservative
* Other: Oxygen gas -Liberal


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists (ASA) physical status I-III Body mass index (BMI) less than 40 kg/m2 Scheduled to undergo robotic-assisted radical laparoscopic nephrectomy. Exclusion Criteria: Patients with a diagnosis of chronic obstructive pulmonary disorder (COPD), severe neurological, cardiopulmonary, psychiatric, or untreated thyroid disorder Chronic pain condition that is being treated with opioids Patients with a hematocrit lower than 30% at the end of surgery, or those with an excessive blood loss, requiring transfusion of blood products during their surgery, will be also excluded from the study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: In the post-anesthesia care unit (PACU), participants will be randomized to receive conservative (titrated to an SpO2 between 90 and 94%) versus liberal (titrated to SpO2 > 96%) oxygen supplementation, via a non-rebreather mask.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Conservative O2 Supplementation<br>Oxygen administration will titrated to a oxyhemoglobin saturation (SpO2) between 90 and 94%. | Other: Oxygen gas -Conservative<br>* Oxygen administration will titrated to a oxyhemoglobin saturation (SpO2) between 90% and 94%.<br>|
| Active Comparator: Liberal O2 Supplementation<br>Oxygen administration will titrated to an SpO2 > 96%. | Other: Oxygen gas -Liberal<br>* Oxygen administration will titrated to a oxyhemoglobin saturation (SpO2) higher than 96%.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transcutaneous partial pressure of carbon dioxide (TcPCO2) | The cumulative segment of time during which the transcutaneous partial pressure of carbon dioxide (TcPCO2: primary outcome) will exceed an upper limit of 45 mmHg (i.e., TcPCO2 > 45 mmHg) | Ninety -minute period immediately post-anesthesia. |