Blood Pressure Drop
The complex phenomenon of circumrescue collapse is not well understood. It can occur just before rescue, during rescue – as the victim is removed from the water - and after rescue, when the person is out of the water. Circumrescue collapse appears, at least in part, to be related to an abrupt drop in blood pressure as the person is removed from the water. In that situation, water pressure on the body is lost and the resulting hypotension is an obvious suspect. It can cause unconsciousness and also heart failure.
Consequently, rescue personnel should be careful about removing a victim from the water in a vertical position, particularly if hoisting into a helicopter. The safer position for the victim is horizontal, so a basket hoist or horizontal sling is preferred rather than using a strop. When pulling a victim onto a boat, have them lie down as soon as possible.
2 Minute Video About Slings and Baskets