Journal of anesthesia
-
We observed the changes in partial pressure of arterial oxygen (PaO 2) and carbon dioxide (PaCO 2) before and during assumption of the lateral position prior to lumbar puncture in 81 patients to investigate whether lung volume decreased and ventilation was suppressed. PaO 2 significantly decreased while the patients were in the lateral position, while PaCO 2 remained unchanged. ⋯ The fact that closing volume increases with age implies that the decrease in functional residual capacity in the lateral position could have caused the decrease in PaO 2. It is therefore advisable to continuously monitor arterial oxygenation using a noninvasive monitor, such as a pulse oximeter, while performing spinal or epidural block, especially in elderly patients.
-
Journal of anesthesia · Jun 1994
Relationship between cardiac output and mixed venous-arterialPCO 2 gradient in sodium bicarbonate-treated dogs.
We examined the relationship between cardiac output (CO) and mixed venous-arterialPCO 2 gradient ([Formula: see text]) along with the other variables derived from arterial and/or mixed venous blood gases in sodium bicarbonate-treated dogs. Six dogs with low cardiac output following cardiopulmonary resuscitation were used. CO, blood gases, and hemoglobin measurements were repeated every 20-30 min after administration of sodium bicarbonate or normal saline. ⋯ Arteriovenous oxygen content difference ([Formula: see text]), mixed venous oxygen saturation ([Formula: see text]), and[Formula: see text] were highly correlated with CO. The correlation coefficients between[Formula: see text],[Formula: see text], and[Formula: see text] werer=-0.81 (P<0.001),r=0.70 (P<0.001), andr=-0.77 (P<0.001), respectively. The results suggest that, if[Formula: see text] is measured during the steady state, except for the period during the transient increase in CO2 elimination just after the administration of sodium bicarbonate,[Formula: see text] can be used as an index of systemic perfusion even after the administration of sodium bicarbonate.
-
Journal of anesthesia · Jun 1994
Intrathecal phentolamine increases blood flow and skin temperature in the hind limbs of dogs.
Spinal anesthesia with local anesthetics increases blood flow and skin temperature in the lower extremities. Although the effect of α2 adrenoceptor agonists on the spinal cord has been confirmed, there has been no such report of the effects of α-adrenoceptor antagonists. We studied the effects of intrathecal administration of phentolamine on the blood flow in the femoral artery and skin temperature in the hind limbs of seven dogs. ⋯ High pad skin temperature continued for 60 min in the L group and for 90 min in the P group. With phentolamine i.v. (1 mg), there were no changes in blood flow in the femoral artery or pad skin temperature; there was only a decrease in blood pressure. In conclusion, the intrathecal α-adrenoceptor antagonist, phentolamine, increases blood flow in the femoral artery and pad skin temperature in hind limbs in dogs similar to lidocaine.
-
Journal of anesthesia · Jun 1994
Differential effects of isoflurane, halothane, and ketamine on the regional methionine-enkephalinlike immunoreactivity in the mouse brain.
The widely used measurement index for anesthetic potency, minimum alveolar concentration (MAC), is hypothesized to be the sum of the effects on multiple neural systems whose contribution to anesthesia differs depending on the agents used. The present study, which compared the effects of halothane, isoflurane, and ketamine, at equipotent level of anesthesia, on the methionine-enkephalinergic neurons in 9 brain regions, showed a significant difference in the methionine-enkephalin-like immunoreactivity (Met-ENK-like IR) among the anesthetics in each region. The order of the Met-ENK-like IR was: halothane > ketamine > isoflurane in the caudatus putamen; halothane > isoflurane ≊ketamine in the nucleus accumbens and the ventral pallidum; halothane ≊isoflurane > ketamine in the globus pallidus, the nucleus dorsomedialis hypothalami, and the nucleus ventromedialis hypothalami; and halothane > isoflurane > ketamine in the arcuate nucleus, the periaqueductal gray, and the nucleus reticularis parvocellularis. These findings indicate that these three anesthetics affect the methionine-enkephalinergic neurons in the motor and pain controlling pathways in different fashions.