摘要:

Inactivation of atracuriumin vivohas been postulated to proceed along two pathways: Hofmann elimination and ester hydrolysis. Since an end product of Hofmann elimination (acrylate) may be potentially toxic, the authors conducted a study to determine the extent of degradation via enzyme catalyzed hydrolysis relative to that via Hofmann elimination. The enzyme carboxylesterase was inhibited by the pretreatment of rats with an organophosphorous compound, triorchotolyl phosphate (TOTP). Skeletal muscle relaxation produced either byd-tubocurarine or succinylcholine was not influenced by the pretreatment. This indicates that TOTP does not alter directly the paralyzing properties of either depolarizing or nondepolarizing muscle relaxants. Relaxation produced by atracurium, however, was prolonged markedly and the rate of recovery from relaxation was decreased. The authors conclude: 1) enzyme-catalyzed hydrolysis is probably responsible for the short duration of action of atracurium; 2) Hofmann elimination, at least in rats, probably is not the principal degradation pathway; and 3) the opportunity forin vivogeneration of large amounts of po tentially toxic end products is less than previously implied.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Transthoracic electric countershock can cause necrotic myocardial lesions in humans as well as experimental animals. The authors investigated the effect on postcountershock myocardial damage of pretreatment with prazosin (0.1 mg/kg), an alpha-1 antagonist; L-metoprolol (0.5 mg/kg), a beta-1 antagonist, and verapamil (0.5 mg/kg), a calcium channel-blocking agent. Twenty dogs were anesthetized with halothane and given two transthoracic countershocks of 295 delivered joules each after drug or vehicle treatment. Myocardial injury was quantitated 24 h following countershock by measuring the uptake of technetium-99m pyrophosphate in the myocardium. Elevated technetium-99m pyrophosphate uptake occurred in visible lesions in most dogs regardless of drug treatment. For each of four parameters of myocardial damage there was no statistically significant difference between control animals and those treated with prazosin, metoprolol, or verapamil. These data suggest that adrenergic or calcium channel-mediated mechanisms are not involved in the pathogenesis of postcountershock myocardial damage.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Loss of righting reflex (LRR) produced by various concentrations of the leucine-enkephalin analog BW831c (TYR.D-ALA.GLY.PHE.D-LEU.NHEt.HCI) was determined in amphibia at 1 atm and 120 atm of helium. EC50for LRR was 22.1 ± 1.6μMand 44 ± 6.9μM, respectively. The octanol/water partition coefficient (P) was 26 ± 3.6, suggesting that this peptide is sufficiently lipid soluble for a classic Meyer-Overton type of anesthetic action. The ratio (EC50at 120 atm)/(EC50at 1 atm) for the peptide (2.0 ± 0.31) was essentially the same as that for the long-chain alcohol, octanol (1.8 ± 0.08), and similar to those reported for phenobarbital and the gaseous anesthetics. Thus, peptide-induced LRR was reversible by pressure. Peptide-induced LRR also was completely reversible by naloxone, whereas octanol-induced LRR was unaffected by up to 100μMnaloxone. These findings are consistent with a dual mechanism of anesthetic action for this peptide: one, an opiate receptor-specific mechanism, reversible with the specific opiate antagonist, naloxone; the other, a nonspecific mechanism, related to lipid solubility and reversible with the application of the physical agent, pressure.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Six patients, ages 29–58 yr, were investigated during barbiturate and fentanyl anesthesia. After intubation with a double-lumen bronchial catheter, one lung was ventilated continuously with 100% O2, and the other was rendered hypoxic during three 15-min periods by ventilation with 95% N2+ 5% O2, with intervening 15-min periods of oxygen ventilation. Cardiac output was determined by thermodilution, and the distribution of blood flow between the lungs was assessed from the excretion of a continuously infused poorly soluble gas (SF6). The first hypoxic challenge resulted in a 10% increase in cardiac output (QT) and a reduction in the fractional perfusion of the test lung from 57% to 31% of QT. The pulmonary artery mean pressure increased by 54%, and the vascular resistance of the test lung increased threefold. The venous admixture increased from 19% to 40% of QT, whereas the inert gas shunt remained unaltered at 15% (inert gases also being eliminated by nitrogen-ventilated areas). The arterial oxygen tension decreased from 353 mmHg to 79 mmHg. On resumption of the control state, central hemodynamics and gas exchange returned to the initial values. The second and third hypoxic challenges resulted in reductions in the fractional perfusion of the test lung to 35% and 37% of QT. All other variables were altered to the same degree as during the first challenge. The authors conclude that hypoxic challenge of one lung in an intravenously anesthetized human subject elicits a maximum vasoconstrictor response within the first 15 min, and this response cannot be potentiated by repeated challenges.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The effects of nitrous oxide, enflurane, and isoflurane on cortical somatosensory evoked potentials (SEPs) were studied in 29 patients undergoing intracranial or spinal operations. Anesthesia was induced with fentanyl (25 μg/kg, iv) plus thiopental (0.5–1.0 mg/kg, iv). In one group of patients (n = 12), nitrous oxide (50%) was compared with enflurane (0.25–1.0%), and in another group (n = 12) nitrous oxide (50%) was compared with enflurane (0.25–1.0%). In all third group of patients (n = 5) with preexisting neurologic deficits, nitrous oxide (50%) was compared with enflurane (0.25–1.0%). In all three groups, one gas was administered for 30 min, and then the alternate gas was administered for 30 min; then the cycle was repeated for a total of two administrations of each of the two anesthetics. SEPs were determined before and after induction of anesthesia and at the end of each 30-min study period. The latencies and amplitudes of the early cortical components of the upper- and lower-extremity SEP were examined. Induction of anesthesia resulted in increases of latency in both upper- and lower-extremity SEPs-without any alteration of amplitude. Nitrous oxide, enflurane, and isoflurane each decreased the amplitude of the upper-extremity SEPs compared with the postinduction value. The amplitude of the upper-extremity SEPs was less during nitrous oxide than with either enflurane or isoflurane. Nitrous oxide decreased the amplitude of lower-extremity SEPs below postinduction value, while enflurane and isoflurane had no effect. Isoflurane and enflurane increased the latency of both upper- and lower-extremity SEPs slightly, while nitrous oxide had no effect. In patients with preexisting neurologic deficits, nitrous oxide decreased amplitude more than enflurane. The authors conclude that during fentanyl-based anesthesia either enflurane or isoflurane (0.25–1.0%) results in less alteration of cortical SEPs than does nitrous oxide (50%), and these concentrations of enflurane or isoflurane are compatible with the generation of waves that are adequate for evaluation.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Despite the widespread use of multiple dose vials (MDV) for anesthetic medications, there is a paucity of data concerning the sterility of in-use MDV. The purpose of this study was to analyze the frequency of bacterial contamination of MDV used in current anesthesia practice. The authors collected weekly samples from 351 in-use MDV for seven consecutive weeks and cultured them using appropriate bacterial growth media. The vials contained drugs including neuromuscular blockers, anticholinergics, and an induction agent. They were sampled from locations designated for elective as well as emergency surgery. Six vial subgroups were studied with multiple samplings for 6–48 days. One-half of all opened vials remained in use after 4–9 days, while less than 5% remained after 6 weeks. No vial yielded bacteria. The authors conclude that the incidence of MDV contamination with live bacteria is low for the anesthetic medications studied. This appeared to be true even for vials with increasing duration of use and for vials from locations where emergency surgery commonly was performed.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID