Beach-Chair Position, Arm Blood Pressure Discrepancy and an AV Fistula
An 82-year-old woman, 92 kg, BMI 34, ASA III with type 2 diabetes and hypertension, is positioned in the beach-chair position for a 3.5-hour arthroscopic shoulder repair under general anesthesia with an interscalene block. She has a history of carpal tunnel syndrome and a left forearm arteriovenous fistula for dialysis. After 20 minutes in the beach chair at 70 degrees, the blood pressure cuff on the right arm reads 88/50 mmHg, while the left-arm cuff reads 128/70 mmHg; the right hand looks pale. The surgeon asks to increase the chair angle to 80 degrees for exposure and to 'just tuck the arm' to speed up draping. You are responsible for positioning and pressure-area checks.
1. Interpret the blood pressure discrepancy and identify the immediate positioning and monitoring concerns.
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Interpretation. A right-arm reading of 88/50 with a left-arm reading of 128/70 is a real discrepancy until proven otherwise. If the right side is the operative side with an interscalene block, sympathetic blockade can cause vasodilation and a lower reading, but a pale hand is not explained by vasodilation alone. Check the cuff size and position, repeat the reading, and assess the right radial pulse, capillary refill and SpO2 on that hand. The arm may be compressed by the tuck or the cuff may be at a different level from the heart in the beach-chair position.
Immediate concerns: possible brachial plexus or arterial compression, unrecognised hypotension, and reduced cerebral perfusion in the head-up position. Notify the anaesthesiologist before changing the angle or the arm position.
2. What specific protections and checks would you implement, and how would you respond to the request to increase the angle and tuck the arm?
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Protections and checks.
- Eyes: lubricate and tape securely; no pressure on the globe.
- Head/neck: keep neutral, avoid extreme flexion/extension, check the ETT is not kinked, secure it.
- Pressure areas: pad occiput, sacrum, heels, elbows and iliac crests; reassess every 30 minutes.
- Right arm: support in neutral alignment, no abduction beyond 90°, no traction; keep the hand visible and check pulse/SpO2.
- Left arm: protect the AV fistula - no BP cuff, no IV, no pressure; pad it.
- Legs: anti-embolism stockings or intermittent compression, knees supported.
- General: safety strap, table brakes, warm air blanket, fluid warmer, and a documented position check.
Response to the surgeon: explain that increasing to 80 degrees may worsen hypotension and cerebral perfusion; agree a staged increase only after the anaesthesiologist reviews the blood pressure and the right arm. 'Tucking' the arm is acceptable only if the pulse and SpO2 remain normal, the arm is padded and not hyperabducted, and the hand stays accessible. Do not rush this to save draping time.
3. What documentation and handover points matter for PACU?
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Documentation and handover.
- Record the beach-chair angle, time, padding used, pressure areas checked, both-arm blood pressures and which arm was used, peripheral pulse/SpO2, and any intervention.
- Note the AV fistula and the instruction not to use that arm.
- Hand over to PACU: prolonged head-up position, any hypotension, right-arm pulse concern, block details, skin condition and the need for neurovascular observations. A clear handover is the best protection if a nerve or pressure injury appears later.