Compression Stocking Use in Shoulder Arthroscopy in Beach Chair

Study Overview
=================
Brief Summary
-----------------
Shoulder arthroscopy is one of the most commonly performed orthopaedic procedures and it is often done with the patient in the upright, or beach chair position (BCP). There have been multiple reported complications associated with the BCP, including cerebral ischemia, loss of vision, ophthalmoplegia, stroke, and even death. It has been reported that patients with a body mass index (BMI) of 34 or greater are as much as 12 times more likely to experience cerebral desaturation events (CDEs) compared to non-obese controls. CDEs in the upright position are hypothesized to be partially related to reduced cardiac preload due to venous pooling in the lower extremities which is exaggerated in obese patients. This prospective observational study aims to determine if the use of compression stockings in obese patients undergoing shoulder arthroscopy in the BCP can reduce the incidence, frequency, or magnitude of CDEs experienced by the patient

Detailed Description
-----------------
There have been numerous studies recently in the orthopaedic surgery and anesthesia literature related to both complications associated with arthroscopy in the BCP and ongoing efforts to improve patient safety. Advantages of this position when compared with the lateral decubitus position include easier anatomic orientation, lack of traction on the brachial plexus, ease of exam under anesthesia, and easier conversion to an open approach if needed. While extremely uncommon, complications such as ischemic brain and spinal cord injury as well as visual loss and ophthalmoplegia have been reported. A recent study reported that obesity increases the likelihood of having a CDE by as many as 12 times. CDEs were defined as intra-operative decreases in regional cerebral tissue oxygen saturation (rSO2) of 20% or greater from baseline as measured by near-infrared spectroscopy (NIRS). Since obesity is so common, it was decided to investigate a measure to potentially help decrease CDEs in this population. The exact etiology of CDEs has not been definitively demonstrated and it is felt to be multifactorial. The sympathetic nervous system normally increases systemic vascular resistance and heart rate to maintain mean arterial blood pressure (MAP) when a person sits up or stands upright. This response is blunted by the vasodilatory effects of intravenous and inhaled anesthetics used in patients undergoing shoulder arthroscopy in the BCP. The result is decreased MAP and cerebral perfusion pressure that can contribute to hypoxic brain injury. The use of sequential compression devices placed on the legs of patients undergoing shoulder arthroscopy in the BCP has been shown to reduce the incidence of hypotension by increasing cardiac preload. This study excluded obese patients (BMI > 30) and did not directly monitor rSO2, but rather only monitored hemodynamic variables. Compression stockings are often used in patients with venous insufficiency to help with pain and to control edema. The stockings compress the soft tissues and veins, and in conjunction with sequential compression devices (SCDs), may help to increase preload in an anesthetized patient in the BCP. To our knowledge, the effect of compression stockings on cerebral perfusion has not been studied. This study aims to determine if the use of compression stockings in obese patients undergoing shoulder arthroscopy in the BCP can decrease the incidence, frequency or magnitude of CDEs as measured by NIRS. We hypothesize that the use of compression stockings will result in decreased incidence and frequency of CDEs in our population.

Official Title
-----------------
The Effect of Compression Stockings on Cerebral Desaturation Events in Obese Patients Undergoing Shoulder Arthroscopy in the Beach Chair Position

Conditions
-----------------
Obesity, Shoulder Impingement

Intervention / Treatment
-----------------
* Device: Thigh-high compression stockings


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age 18 years or older BMI greater than or equal to 30 kg/m^2 Capable of receiving an interscalene nerve block. Exclusion Criteria: Age < 18 History of carotid artery stenosis equal to or greater than 90% History of stroke History of transient ischemic attack History of syncope History of vision loss

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

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

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

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

Design Details

Primary Purpose: Prevention
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Prospective Case<br>Patients with a BMI of 30 kg/m^2 or greater who underwent shoulder arthroscopy in the beach chair position and were monitored intraoperatively using near-infrared spectroscopy while wearing thigh-high compression stockings. | Device: Thigh-high compression stockings<br>* The intervention in this study are thigh-high compression stockings manufactured by Covidien.<br>* Other names: Thrombo-Embolic Deterrent (TED) Anti-Embolism Stockings;|
| No Intervention: Historical Control<br>Patients with a BMI of 30 kg/m^2 or greater who underwent elective shoulder arthroscopy in the beach-chair position and were monitored intraoperatively using near-infrared spectroscopy but without wearing compression stockings. | |

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cerebral Desaturation Event | The prevalence of a cerebral desaturation event is compared between prospective patients who underwent shoulder arthroscopy in the beach chair position while wearing thigh-high compression stockings versus historical control patients who underwent shoulder arthroscopy in the beach chair position and did not wear thigh-high compression stockings. | Assessed intraoperatively, an average of 114 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Operation Time | The length of operation time (in minutes) is compared between prospective patients who underwent shoulder arthroscopy in the beach chair position while wearing thigh-high compression stockings versus historical control patients who underwent shoulder arthroscopy in the beach chair position and did not wear thigh-high compression stockings. | End of surgery | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
obesity, arthroscopy, shoulder, beach chair, compression hose