Respiratory and cardiovascular effects of doxapram and theophylline for the treatment of asphyxia in neonatal calves.

Respiratory stimulants are widely used in asphyxic neonatal calves despite a lack of data about their effectiveness and indications of possible side effects. The effect of doxapram and theophylline on respiratory, cardiovascular, and acid-base variables was investigated in 10 healthy neonatal calves (Bos Taurus). A venous, a peripheral arterial, and a pulmonary arterial catheter were placed, and central venous, pulmonary, and systemic blood pressures and cardiac output were measured using thermodilution technique. Doxapram, but not theophylline, led to an immediate increase in respiratory rate (P