Anesthesia and analgesia
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Anesthesia and analgesia · Jan 1984
Concentrations of lactate and pyruvate in maternal and neonatal blood with different intravenous fluids used for prehydration before epidural anesthesia.
This study assesses the effects of infusion of 1200 ml of four different intravenous solutions before epidural anesthesia for cesarean section on maternal and neonatal whole blood lactate (L), pyruvate (P), excess lactate (XL), L/P ratio, and base excess (BE) in four equal groups of patients. Patients in group I (n = 15) received normal saline; those in group II, Ringer's lactate (RL); those in group III, RL with 20 g of glucose; and those in group IV, Plasma-Lyte A. Maternal venous concentrations of L increased significantly in all groups after infusion, but P increased only in group III. ⋯ However, neither neonatal Apgar scores nor maternal and neonatal BE significantly differed among the four groups. No neonate developed hypoglycemia. It is concluded that all the four intravenous fluids, despite differences in their effects on blood L and P concentrations, produce clinically satisfactory maternal and neonatal outcome.
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Anesthesia and analgesia · Jan 1984
High-dose hydromorphone (Dilaudid) for coronary artery bypass surgery.
The hemodynamic effects of high-dose hydromorphone hydrochloride (H), 1.25 mg/kg, were investigated in 10 patients with normal ventricular function undergoing coronary artery bypass graft (CABG) surgery. One patient with unstable angina was excluded from the study because of hypotension and facial flushing after a 6-mg test dose of H. Nine patients showed no significant change in heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), left ventricular stroke work index (LVSWI), systemic vascular resistance (SVR), pulmonary capillary wedge pressure (PCWP), or coronary perfusion pressure (CPP) after H; central venous pressure (CVP) increased significantly (P less than 0.05). ⋯ Vasodilators were required in eight patients before aortic cannulation and after extracorporeal circulation. Mean time to awakening was 7.6 hr after the full dose of H, and extubation was performed the morning after surgery (21 hr after H) according to our usual practice. We conclude that very large doses of H (equivalent in analgesic terms to 10 mg/kg of morphine sulfate) are well tolerated by most patients undergoing CABG surgery, but unconsciousness and complete suppression of sympathetic responses require supplementation of H with additional anesthetic agents or vasodilators.
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Anesthesia and analgesia · Dec 1983
Comparative StudyDifferential sensitivities of mammalian nerve fibers during pregnancy.
The onset of conduction blockade in the vagus nerve of pregnant and nonpregnant rabbits was studied utilizing an in vitro sheath nerve preparation. The time required for 50% depression of the action potential (AP) of A, B, and C vagal fibers from five pregnant and six nonpregnant animals was determined after the application of bupivacaine (0.35 mM). The onset of conduction block occurred in 6.7-12.1 min in the A, B, and C fibers from pregnant animals compared to onset times of 17.9-31.6 min in nerves taken from nonpregnant rabbits. ⋯ The results suggest either an increased sensitivity of nerve fibers from pregnant animals to bupivacaine or an enhanced diffusion of the bupivacaine to the membrane receptor site. Mechanical factors are clearly not responsible for the observed results. Hormonal factors may play a role in the decreased anesthetic latency, because progesterone levels were significantly higher in the pregnant animals.