Scuba Diving Before a Morning Flight
On Saturday afternoon, a private pilot completes three open-water scuba dives in one day: 18 m for 35 minutes, 15 m for 30 minutes, and 12 m for 25 minutes. The last dive surfaces at 13:00. He plans to fly home the next morning at 08:00 in a normally aspirated light aircraft, cruising at 8,500 ft for 1.5 hours. On Sunday morning he reports mild pain in his left shoulder and tingling in his right hand. He attributes this to sleeping awkwardly. He feels otherwise well, has no fever, and his pulse oximetry is 97% at sea level. The weather is good, and he has not consumed alcohol in the last 24 hours. He asks whether he can fly as planned or should drive instead.
1. Identify the primary aeromedical hazard and explain why the planned flight increases the risk.
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The primary hazard is decompression sickness (DCS). The pilot made three dives in one day, including repetitive exposure. During diving, nitrogen dissolves in tissues; after surfacing, residual nitrogen can form bubbles if ambient pressure falls too quickly. Flying at 8,500 ft reduces ambient pressure further, effectively adding another altitude exposure after the dives. The shoulder pain and hand tingling are consistent with DCS, and tingling suggests possible neurological involvement rather than a harmless sleep position.
The commonly taught minimum wait after multiple dives is 24 hours. Here the interval is only 19 hours (13:00 Saturday to 08:00 Sunday), so the flight is inside the risk window. A normal pulse oximeter does not exclude DCS because it measures oxygen saturation, not nitrogen bubbles or tissue damage. The presence of neurological symptoms makes the situation more concerning. Therefore the flight should not proceed.
2. What should the pilot do next, and why is a normal pulse oximeter reading not reassuring?
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He should not fly, should not dive again, and should seek prompt medical assessment for possible DCS. He should contact a diving medicine specialist or emergency service, describe the dives and symptoms, and follow advice about recompression and flying. Driving is safer than flying, but even driving should be cleared by a doctor if symptoms are neurological. He should also inform his passengers and arrange alternative transport.
Pulse oximetry at sea level can be normal in DCS because the problem is bubbles in tissue and venous blood, not necessarily low arterial oxygen saturation. Waiting for symptoms to worsen is unsafe; early treatment improves outcomes. The key decision is to accept the no-go and not let the planned schedule override medical risk.