Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1993
ReviewCocaine abuse in the parturient and effects on the fetus and neonate.
The growing use of cocaine among pregnant women and women of childbearing age has become an issue of great concern to physicians. Cocaine abuse among parturients is associated with multi-target organ involvement, including the cardiovascular, respiratory, neurologic, and hematologic systems. ⋯ Although a history of premature rupture of membranes, smoking, alcohol use, syphilis serology, and use of other illicit drugs suggests cocaine abuse, the single most important predictor is the absence of prenatal care. The intraoperative anesthetic management should take into consideration the different effects of cocaine on the mother, the fetus, and the neonate.
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Anesthesia and analgesia · Oct 1993
Multicenter Study Clinical TrialEffects on recovery when isoflurane is used to supplement propofol-nitrous oxide anesthesia.
During propofol-nitrous oxide (N2O) anesthesia, volatile anesthetics are frequently administered to treat signs of inadequate anesthesia and to decrease the possibility of intraoperative awareness. Because the clinical effects of this combination have not been examined rigorously, we used data from the 1989-90 Phase IV clinical trial with propofol to evaluate recovery from propofol-N2O anesthesia with and without supplementation with isoflurane. In this study involving 15,806 patients at 1722 institutions, propofol was administered for induction and maintenance of anesthesia with N2O for procedures lasting less than 60 min. ⋯ Adjunctive use of isoflurane prolonged the time to awakening and to becoming oriented, but discharge times were similar for the two groups. The incidence of postoperative nausea, vomiting, recall, and excitement did not differ between the two groups. We conclude that the addition of isoflurane to a propofol-N2O anesthetic does not alter recovery from anesthesia.
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Anesthesia and analgesia · Oct 1993
Randomized Controlled Trial Clinical TrialThe orbicularis oculi and the adductor pollicis muscles as monitors of atracurium block of laryngeal muscles.
The aim of this study was to determine whether atracurium-induced neuromuscular block at the laryngeal adductor muscles could be predicted by visual inspection of either adductor pollicis or orbicularis oculi responses. Twenty-one ASA Class I or II patients were anesthetized with propofol (2-2.5 mg/kg) and fentanyl (2-5 micrograms/kg). Tracheal intubation was performed without neuromuscular blocking drugs. ⋯ In patients receiving atracurium 0.5 mg/kg, laryngeal and orbicularis oculi responses were abolished faster (mean +/- SD: 132 +/- 80 and 146 +/- 58 s, respectively) than the adductor pollicis muscle (243 +/- 55 s; P < 0.05). There was a significant correlation (r = 0.94; P < 0.001) between neuromuscular block onset time at the laryngeal adductor and orbicularis oculi muscles but not between laryngeal and thumb muscles. The authors conclude that, after injection of atracurium, laryngeal adductor and orbicularis oculi blocks have similar intensities and time courses.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Oct 1993
Nitrous oxide decreases solubility of isoflurane and halothane in blood.
This study investigated the effects of carrier gases on the solubility of isoflurane or halothane in blood. The blood/gas partition coefficients (lambda blood/gas) of 1 minimum alveolar anesthetic concentration of isoflurane or halothane in 100% oxygen, 30% oxygen with 70% nitrous oxide, 100% nitrous oxide or air were measured at 37 degrees C, with blood from four donors. ⋯ The values of isoflurane or halothane in 100% nitrous oxide (1.29 +/- 0.03; 2.25 +/- 0.08) and in a gas mixture of 30% oxygen and 70% nitrous oxide (1.33 +/- 0.04; 2.29 +/- 0.05) were lower (P < 0.05) than those obtained with 100% oxygen (1.40 +/- 0.03; 2.37 +/- 0.04). We conclude that nitrous oxide decreases the lambda blood/gas of isoflurane or halothane, and that this change of solubility, although small, increases the uptake rate of halothane or isoflurane.
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Reportedly, during spinal anesthesia, the shivering threshold is reduced approximately 1 degree C but the vasoconstriction threshold remains normal. Such divergence between the shivering and vasoconstriction thresholds is an unusual pattern of thermoregulatory impairment and suggests that the mechanisms of impairment during regional anesthesia may be especially complex. Accordingly, we sought to define the pattern of thermoregulatory impairment during spinal anesthesia by measuring response thresholds. ⋯ Spinal anesthesia significantly decreased the thresholds for vasoconstriction and shivering, and the decrease in each was approximately 0.5 degree C. The range of temperatures not triggering thermoregulatory responses (those between sweating and vasoconstriction) was 0.9 +/- 0.6 degree C during spinal anesthesia. The synchronous decrease in the shivering and vasoconstriction thresholds during spinal anesthesia is consistent with thermoregulatory impairment resulting from altered afferent thermal input.