The Effect of Ventilation on Cerebral Oxygenation in the Sitting Position

Study Overview
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Brief Summary
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The aim of this clinical investigation is to determine the effect of intraoperative ventilation on cerebral oxygen saturation in patients undergoing arthroscopic shoulder surgery in the beach chair position (BCP)

Detailed Description
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Recent developments in near-infrared spectroscopy technology now permit rapid assessment of cerebral oxygenation (SctO2) using non-invasive probes. A high incidence cerebral desaturation events (CDE-defined as a decrease in SctO2 values below 20% of baseline measures or absolute SctO2 values ≤ 55 for ≥ 15 seconds) have been observed in previous investigation of patients undergoing shoulder surgery in BCP with hyperventilation. The investigators hypothesize that the incidence of CDE will be reduced in patients ventilated at normocapnic levels (end-tidal carbon dioxide values (ETCO2) of 40-42 mm Hg) when compared to subjects hyperventilated (ETCO2 of 30-32 mm Hg) in the operating room. Patients undergoing shoulder surgery in the BCP will be randomized to a hypocapnic group (ETCO2 of 30-32 mm Hg) or a normocapnic group (ETCO2 of 40-42 mm Hg). Cerebral oxygenation will be measured continuously throughout the procedure to assess perioperative SctO2 values and the incidence of CDE. The investigators previously observed an association between CDE in the operating room and postoperative nausea and vomiting. Therefore, the effect of ventilatory pattern and intraoperative SctO2 on clinical recovery will also be determined.

Official Title
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The Effect of Ventilation on Cerebral Oxygenation in the Sitting Position

Conditions
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Cerebral Ischemia

Intervention / Treatment
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* Other: Hypocapnic group
* Other: Normocapnic group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients presenting for elective shoulder arthroscopy under general anesthesia in the BCP. Exclusion Criteria: Exclusion criteria include 1) history of pre-existing cerebrovascular disease or orthostatic hypotension 2) age < 18 years 3) American Society of Anesthesiologists Physical Status IV or V.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 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
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Hypocapnic group<br>Patients will be ventilated to an ETCO2 of 30-32 mm Hg. | Other: Hypocapnic group<br>* Patients will be ventilated to an ETCO2 of 30-32 mm Hg.<br>|
| Active Comparator: Normocapnic group<br>Patients will be ventilated to an ETCO2 of 40-42 mm Hg | Other: Normocapnic group<br>* Patients will be ventilated to an ETCO2 of 40-42 mm Hg<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of Cerebral Desaturation Events | Cerebral desaturation events were measured with near-infrared spectroscopy | Intraoperative-first 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Patients Experiencing Nausea and Vomiting | Assessed by recovery nurses | Postanesthesia care unit-first 2 hours | 
| Postanesthesia Care Unit Length of Stay (Total Time) |  | Approximately 5 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cerebral desaturation events, Cerebral oximetry, Beach chair position