The Accuracy of Peripheral Perfusion Index and Inferior Vena Cava Collapsibility Index for Predicting Hypotension in Patients Undergoing Shoulder Arthroscopy in Beach Chair Position: A Prospective Observational Study

Shoulder arthroscopy is a minimally invasive surgical procedure widely utilized for the diagnosis and treatment of various shoulder joint pathologies, it is commonly performed with patients positioned in the beach chair position , which enhances access to the shoulder joint.

In the beach chair position, the patient is placed in in a semi-sitting position with an angle ranging from 30-60 degrees, depending on surgeon preference and procedure requirements. The lower extremities are typically slightly flexed. Patient's head is securely supported using a specialized head rest or padding while the operative arm draped freely or positioned using a mechanical arm holder for optimal access to the shoulder joint.

Nonetheless, the beach chair position has unique physiological challenges including reduced venous return, decreased cardiac output which eventually results in an increased risk of hypotension. Hypotension during surgery can compromise organ perfusion, potentially leading to cerebral ischemia, myocardial dysfunction, and delayed recovery, thus blood pressure monitoring across the procedure is crucial for optimizing patient safety, outcomes and to prevent potential complications.

Various parameters have been implemented to predict hypotension in beach chair position including; pre-induction values of mean arterial pressure , stroke volume variation , cardiac index and stroke volume index but the inconsistent sensitivity and specificity, together with the necessity for invasive monitoring, may limit their routine use.

Ultrasound measurement of the inferior vena cava collapsibility index and inferior vena cava diameter has the advantages of easy performance, repeatability and low cost and has often been used to predict fluid responsiveness in emergency and critical care settings. Recently, this noninvasive hemodynamic assessment method was introduced to predict post induction hypotension in the operating room . However, its utility remains controversial across different population settings and different types of anaesthesia.