The effect of respiratory alkalosis on oxygen consumption after passive hyperventilation was studied in eight dogs. PaCo2 decreased from 32.1 to 13.6 torr, pH increased from 7.43 to 7.72, and oxygen consumption increased from 116.5 to 147.5 ml/m2/min. Venous admixture decreased from 17.1 to 8.8 per
This study was designed to evaluate the effects of induction of enflurane or halothane anesthesia on the distribution and elimination of previously administered intravenous aminophylline, and to evaluate the effect of previously administered intravenous aminophylline on the uptake of enflurane or halothane. Fifty-four dogs were studied: 6 received no anesthetic, 24 received enflurane, and 24 halothane. The six animals receiving no anesthetic were given 10 mg/kg of aminophylline. In each of the two groups of 24 animals, six animals served as controls and received no aminophylline. Of the other 18 animals in each group, six received 10 mg/kg of aminophylline, six received 25 mg/kg of aminophylline, and six received 50 mg/kg of aminophylline intravenously before induction of enflurane or halothane anesthesia. The redistribution (alpha) phase of theophylline was similar when anesthesia was induced with either enflurane or halothane and slightly more rapid when no anesthetic was given following aminophylline administration. The elimination (beta) phase of theophylline in the presence of either anesthetic was not significantly different than when no anesthetic was administered. The uptake of enflurane or halothane was unaffected by prior administration of aminophylline. Differences in arrhythmogenicity between enflurane and halothane after aminophylline administration are not related to alterations in theophylline pharmacokinetics or anesthetic uptake.
Carbon dioxide washout curves were determined in hyperventilated dogs. Direct measurement of mixed venous carbon dioxide tension allowed calculation of changes in whole-body CO 2 stores. The average whole-body CO 2 dissociation constant in ten studies was 3.73 ml/kg mm. The limiting factor in reaching a new steady-state value was represented by a slow compartment in the washout curve. The average rate constant for this compartment was 0.062 min –1 . The slowest compartment in this analysis has a 98% change in 1 hr, therefore the experimentally determined whole-body dissociation constant should closely approximate actual changes in tissue CO 2 stores, excluding bone and fat.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)