Total Shoulder Arthroplasty Near-infrared Spectroscopy

Study Overview
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Brief Summary
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The purpose of this study is to measure cerebral oxygenation and cardiac output of total shoulder replacement patients undergoing general anesthesia (GA) and positive-pressure ventilation (PPV). We hypothesize that cerebral desaturation occurs frequently during GA with PPV, but is rare during GA and spontaneous ventilation. We also hypothesize that cardiac output usually is well maintained under GA in the sitting position when epinephrine is used, but that decreased cardiac output increases the risk of cerebral desaturation.

Official Title
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The Effects of Positive-pressure Ventilation on Cerebral Oxygenation and Cardiac Output in Total Shoulder Arthroplasty.

Conditions
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Cerebral Ischemia

Intervention / Treatment
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* Device: Casmed Fore-Sight Elite
* Device: Non-invasive Cardiac Output Monitor (NICOM)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients 18-99 undergoing total shoulder arthroplasty Planned general anesthesia + brachial plexus nerve block Planned arterial catheter Exclusion Criteria: Patients younger than 18 years older and older than 99 Patients not intending to receive general anesthesia and peripheral nerve block Indication for endotracheal tube BMI ≥ 30 Ejection Fraction (if known) < 50% Known significant restrictive or obstructive pulmonary disease Patients with a history of transient ischemic attack (TIA) or stroke Patients with recent signs or symptoms of myocardial ischemia Current stress test positive for ischemia Intolerance to study medications pre-existing contraindication to regional anesthesia infection at block site pre-existing neurological injury to operative limb Non-English speaking patients

Ages Eligible for Study
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Minimum Age: 18 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Near-infrared spectroscopy<br>Casmed Fore-Sight Elite and Non-invasive Cardiac Output Monitor (NICOM) | Device: Casmed Fore-Sight Elite<br> <br> Device: Non-invasive Cardiac Output Monitor (NICOM)<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Cerebral Desaturation Events | The number of Cerebral Desaturation Events (CDE) that occured. CDE is defined as a reduction in cerebral tissue oxygen saturation of >20% from baseline that lasts for 90 seconds or longer. | Day of surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cardiac Output (CO) | Cardiac output of patients as measured in liters per minute | Day of surgery | 
| Cardiac Index (CI) | Average cardiac index for patients, a measurement of how efficient the heart is pumping. Measured in liters per minute per meters squared of heart size. | Day of surgery | 
| Stroke Volume (SV) | Stroke volume, the amount of blood pumped by the left ventricle of the heart with each contraction. Measured in milliliters. | Day of surgery | 
| Mean Arterial Pressure (MAP) | mean arterial pressure and noninvasive blood pressure will be represented as a percentage of baseline after surgery. A lower percentage is a worse outcome. | Day of surgery | 
| End Tidal Carbon Dioxide (ETCO2) | a lower score is a better outcome. | Day of surgery | 
| Intravenous Fluid Volume |  | Day of surgery |