Anesthesiology
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To examine the association between anemia and postoperative apnea in former preterm infants, 24 former preterm infants of less than 60 weeks postconceptual age undergoing inguinal hernia repair were studied. A hematocrit of at least 25% was required for study participation. General endotracheal inhalational anesthesia, supplemented with neuromuscular blockade and controlled ventilation, was used. ⋯ Anemic infants had an 80% incidence of postoperative apnea versus 21% in infants with a normal hematocrit (P less than .03). In the infants who developed postoperative prolonged apnea and/or bradycardia, a prior history of apnea was equally present in both groups (21% in group 1 and 20% in group 2). This study shows that anemia in former preterm infants can be associated with an increased incidence of postoperative apnea.
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Prior reports suggest cerebral blood flow (CBF) responses to changing bypass (systemic) flow rates may differ between alpha-stat and pH-stat management. To compare the effect of blood gas management upon CBF responses to changing systemic flow and pressure, 15 New Zealand White rabbits, anesthetized with fentanyl and diazepam, underwent nonpulsatile cardiopulmonary bypass at 25 degrees C. One group of animals (n = 8) was randomized to alpha-stat blood gas management that maintained arterial carbon dioxide tension (PaCO2) approximately 40 mmHg when measured at 37 degrees C. ⋯ There were no significant differences between groups with respect to bypass flow rate, mean arterial pressure (MAP), central venous pressure, temperature, hematocrit, arterial oxygen tension (PaCO2), or bypass duration at any measurement point. MAP decreased significantly, from approximately 80 to approximately 65 mmHg with decreasing bypass flow (P = 0.0001). Over the entire range of bypass flows, CBF decreased with decreasing bypass flow (P = 0.001), and the degree of change was equivalent among regions and between groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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The anesthetic interactions of midazolam and fentanyl were determined in terms of enflurane MAC reduction in dogs. In part 1, 8 animals received an intravenous (iv) loading dose of fentanyl followed by a constant infusion at 0.05 micrograms.kg-1.min-1 to produce a stable enflurane MAC reduction of approximately 20%. Midazolam was then administered in a series of three incremental loading doses and infusions (2.4, 9.6, and 28.8 micrograms.kg-1.min-1 previously determined to produce enflurane MAC reductions of approximately 30, 45, and 60%, respectively. ⋯ The fentanyl concentrations in plasma remained stable at 1.0 +/- 0.3 ng/ml (mean +/- standard deviation [SD], part 1) and 3.1 +/- 0.5 ng/ml (part 2) throughout the study and, in the absence of midazolam, reduced enflurane MAC by 28 +/- 11 and 44 +/- 5%, respectively. The addition of midazolam produced significant further reductions in enflurane MAC, but the reductions were less than those predicted on the basis of an additive interaction. Naloxone returned enflurane MAC reduction to that expected for midazolam alone (part 1).(ABSTRACT TRUNCATED AT 250 WORDS)
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We compared the duration of action and recovery times for vecuronium in normothermic and mildly hypothermic patients. Ten patients were actively cooled to a central body temperature near 34.5 degrees C, and ten were maintained at a normothermic central temperature (greater than 36.5 degrees C); temperature was measured in the distal esophagus. Vecuronium 0.1 mg/kg was administered as an intravenous (iv) bolus to all patients, and the evoked mechanical response to train-of-four stimulation was recorded. ⋯ Vecuronium's duration of action (from injection of drug until T1 = 10%) was 28 +/- 4 and 62 +/- 8 min during normothermia and hypothermia, respectively (P less than 0.05). The corresponding values for spontaneous recovery from T1 = 10% to TOF ratio greater than 75% were 37 +/- 15 and 80 +/- 24 min (P less than 0.05), and for neostigmine-induced recovery were 10 +/- 3 and 16 +/- 11 min (difference not significant). We conclude that mild hypothermia increases the duration of action of and time for spontaneous recovery from vecuronium-induced neuromuscular blockade.
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Randomized Controlled Trial Multicenter Study Clinical Trial
The effects of the addition of sufentanil to 0.125% bupivacaine on the quality of analgesia during labor and on the incidence of instrumental deliveries.
In a double-blinded, randomized, prospective multi-center study of 695 women, we investigated whether epidural injection of sufentanil added to 0.125% bupivacaine with epinephrine (1:800,000) reduces the total amount of local anesthetic required, resulting in less motor blockade and reduced incidence of instrumental deliveries, and improves the quality of analgesia provided by this low concentration of local anesthetic without jeopardizing the safety of the baby. In addition, other potential benefits of sufentanil (such as decrease in the incidence of shivering) and side effects were examined. ⋯ The only side effect that occurred more frequently after sufentanil was pruritus. We conclude that epidural injection of 10-30 micrograms sufentanil added to 0.125% bupivacaine with epinephrine (1:800,000) improved the quality of analgesia during labor and reduced the incidence of instrumental deliveries without jeopardizing the safety of the baby.