Effects of nicotinic acid on plasma volume loss of experimental dysbarism.

Two groups of dogs anesthetized with sodium pentobarbital were subjected to compression of 60 psig for 60 min and decompressed at the rate of 10 psi/min without staging. Plasma volume was measured in each group by I131-tagged albumin dilution technique prior to compression, 10 min and 60 min after decompression. One group of animals received no other treatment and the other group received 15 mg/kg of body weight of nicotinic acid by intravenous injection immediately prior to compression and an additional 7.5 mg/kg of body weight of nicotinic acid 30 min after decompression. Both the untreated and the nicotinic acid-treated animals lost significant plasma volume at both the 10- and 60-min postdecompression measurements. Nicotinic acid-treated animals lost significantly less plasma.