Effect of hypoxemia on pharmacokinetics of endotracheal lidocaine in dogs.

Endotracheal administration is an effective alternative method for giving drugs in the many clinical situations in which it is difficult or impossible to quickly obtain an intravenous line. Yet whether various clinical conditions such as hypoxemia have any effect on endotracheal drug therapy is not known. Sixteen sets of plasma lidocaine levels were measured at 5, 15, 30, and 60 min after endotracheal lidocaine administration in eight dogs. Each dog was given the same dose of endotracheal lidocaine by the same technique of administration while in both a normal control state (Group I = 'Non-hypoxemia', mean Po2 = 98) and during hypoxemia (Group II = "Hypoxemia", mean Po2 = 36). Significantly higher plasma lidocaine levels occurred in the hypoxemic state (Group II) at time = 5 min while there was no significant difference in plasma lidocaine levels at time = 15, 30, and 60 min. Mean plasma lidocaine levels (micrograms/ml) at 5 min were: Group I = 1.38, Group II = 2.36 (significant at P less than 0.05). Plasma lidocaine levels were: Group I = 1.61 vs. Group II = 1.63 at time = 15 min, Group I = 1.11 vs. Group II = 1.10 at time = 30 min, and Group I = 0.54 vs. Group II = 0.51 at time = 60 min. Thus, there was a higher peak plasma lidocaine level and a shorter time to peak plasma lidocaine levels in the hypoxemic dogs.(ABSTRACT TRUNCATED AT 250 WORDS)