Ventilation Strategies, Anesthetic Techniques and Cerebral Oxygenation in the Beach Chair Position

April 5, 2022 updated by: Paul Picton, University of Michigan

The Influence of Basic Ventilation Strategies and Anesthetic Techniques on Cerebral Oxygenation in the Beach Chair Position

The seated or "beach chair" position during surgery and general anesthesia decreases brain oxygen levels and can result in stroke. As such, poor neurological outcome following beach chair positioning is a growing concern. In the proposed study the investigators test the hypothesis that changes in ventilation strategy and anesthetic technique can affect cerebral oxygenation in anesthetized patients in the beach chair position.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This is a prospective cohort study with randomized nested design. Patients presenting for shoulder surgery will be randomized to receive desflurane or total intravenous anesthesia with propofol. Regional cerebral oxygenation will be measured using the INVOS 5100C monitor (Covidien, Boulder, CO). Depth of anesthesia will be maintained within a Bispectral Index range of 40-60. Following positioning, inspired oxygen fraction and minute ventilation will be sequentially adjusted. At each set point, regional cerebral oxygenation will be recorded and venous blood gas analysis performed. Statistical analysis will be repeated measures analysis of variance in which ventilation strategy is the within-subjects factor and anesthetic technique is the between-subjects factor; post hoc Tukey's correction will be used for multiple comparisons. If simple maneuvers of ventilation and anesthetic technique can prevent low brain oxygen levels, patient outcome may be improved.

Study Type

Interventional

Enrollment (Actual)

67

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Michigan
      • Ann Arbor, Michigan, United States, 48109
        • University of Michigan

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 85 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • scheduled for elective arthroscopic shoulder surgery in the beach chair position under general anesthesia with supplemental interscalene block

Exclusion Criteria:

  • refusal to give consent
  • ineligible for interscalene block
  • history of cardiovascular disease
  • history of cerebrovascular disease
  • hypertension
  • respiratory failure
  • non-English speaker

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Desflurane
Patients will receive general anesthesia with desflurane. Both arms have rSO2 measured and undergo identical changes in ventilation strategy.
Other: Inspired oxygen fraction / end tidal carbon dioxide

Following induction of anesthesia, FIO2 and minute ventilation will be sequentially adjusted to achieve:

  1. FIO2 30% (70% nitrogen), PETCO2 30mmHg - supine position.
  2. FIO2 30% (70% nitrogen), PETCO2 30mmHg - beach chair position.
  3. FIO2 100%, PETCO2 30mmHg - beach chair position.
  4. FIO2 100%, PETCO2 45mmHg - beach chair position.
  5. FIO2 30% (70% nitrogen), PETCO2 30mmHg - beach chair position.
Experimental: Propofol
Patients will receive total intravenous general anesthesia (TIVA) with propofol. Both have rSO2 measured and undergo identical changes in ventilation strategy.
Other: Inspired oxygen fraction / end tidal carbon dioxide

Following induction of anesthesia, FIO2 and minute ventilation will be sequentially adjusted to achieve:

  1. FIO2 30% (70% nitrogen), PETCO2 30mmHg - supine position.
  2. FIO2 30% (70% nitrogen), PETCO2 30mmHg - beach chair position.
  3. FIO2 100%, PETCO2 30mmHg - beach chair position.
  4. FIO2 100%, PETCO2 45mmHg - beach chair position.
  5. FIO2 30% (70% nitrogen), PETCO2 30mmHg - beach chair position.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Regional Cerebral Oxygenation (rSO2) Before and 5 Minutes After Each Change in Ventilation Strategy
Time Frame: duration of surgery, generally no more than 90 minutes total

rSO2 will be recorded as a "snap shot." A mean value from right and left sides will be calculated for each patient at each study point.

Set Point 1: FIO2 30% (70% nitrogen), PETCO2 30mmHg - supine position. Set Point 2: FIO2 30% (70% nitrogen), PETCO2 30mmHg - beach chair position. Set Point 3: FIO2 100%, PETCO2 30mmHg - beach chair position. Set Point 4: FIO2 100%, PETCO2 45mmHg - beach chair position. Set Point 5: FIO2 30% (70% nitrogen), PETCO2 30mmHg - beach chair position.

With each set point, the value shown is the absolute change from baseline.
duration of surgery, generally no more than 90 minutes total
Regional Cerebral Oxygenation (rSO2) Values
Time Frame: duration of surgery, generally no more than 90 minutes total

Regional cerebral oxygenation (rSO2) values at the set ventilatory points of the study for each anesthetic choice.

Set Point 1: FIO2 30% (70% nitrogen), PETCO2 30mmHg - supine position. Set Point 2: FIO2 30% (70% nitrogen), PETCO2 30mmHg - beach chair position. Set Point 3: FIO2 100%, PETCO2 30mmHg - beach chair position. Set Point 4: FIO2 100%, PETCO2 45mmHg - beach chair position. Set Point 5: FIO2 30% (70% nitrogen), PETCO2 30mmHg - beach chair position.
duration of surgery, generally no more than 90 minutes total

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Michigan

Investigators

  • Principal Investigator: Paul Picton, MD, University of Michigan

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2012

Primary Completion (Actual)

September 1, 2014

Study Completion (Actual)

September 1, 2014

Study Registration Dates

First Submitted

February 9, 2012

First Submitted That Met QC Criteria

February 16, 2012

First Posted (Estimate)

February 17, 2012

Study Record Updates

Last Update Posted (Actual)

April 6, 2022

Last Update Submitted That Met QC Criteria

April 5, 2022

Last Verified

April 1, 2022

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • HUM00049747

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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