ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Human skin mast cell preparations were incubated with thiopental, thiamylal, methohexital, and pentobarbital in concentrations ranging from 10−5M to 10−3M. Both thiopental- and thiamylal-induced dose-related histamine release, with thiamylal having a significantly greater effect than thiopental (P< 0.05). In contrast, incubation of skin mast cell preparations with the same concentrations of pentobarbital and methohexital failed to increase histamine release above spontaneous levels at any concentration. The release of histamine by thiopental and thiamylal was not accompanied by the leakage of lactic dehydrogenase (LDH). Although a demonstration of histamine releasein vitrois not proof that clinical symptoms are causally related to histamine releasein vivo, methohexital may be preferred as the induction agent in patients showing extreme sensitivity to histamine (asthmatics) or increased histamine releasability (atopics).

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The effects of halothane on renal hemodynamics under both normovolemic and hypovolemic conditions were investigated in chronically instrumented conscious dogs whose homeostatic mechanisms were not altered by the presence of preexisting drugs. Renal blood flow and aortic pressure were assessed by prior implantation of Doppler ultrasonic flow probes on the renal artery and a catheter in the descending aorta. Administration of halothane to conscious normovolemic dogs (Group HN) resulted in 11–26% decreases in renal vascular resistance with no significant changes occurring in renal blood flow. In a second group of animals made hypovolemic while awake (Group AH), 30% of the blood volume was removed over one-half hour. In response to hemorrhage, these conscious animals' renal blood flow did not significantly change from the normovolemic control, and renal vascular resistance significantly decreased. With no further intervention, renal vascular resistance and renal blood flow remained unchanged from the level achieved after the 30% hemorrhage. A third group of animals (Group HH) was hemorrhaged in a manner similar to that of Group AH. They also showed no significant changes in renal blood flow and a significant decrease in renal vascular resistance in response to hemorrhage. Thereafter, administration of halothane, as in Group HN, to this group produced 11–23% decreases in renal vascular resistance with no significant decline in renal blood flow from the hypovolemic control levels established after hemorrhage. The author concludes the following: 1) administration of halothane to normovolemic conscious dogs does not decrease renal blood flow; 2) a moderate degree of acute hemorrhagic hypovolemia does not decrease renal blood flow in conscious dogs; and 3) administration of halothane to acutely hypovolemic conscious dogs does not impair renal perfusion.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The authors developed a new method of intrathecal local anesthetic injection in rabbits in order to study the relationship between anesthetic concentration and impaired neurologic function. They found that none of the local anesthetics studied produced persistent neurologic damage in concentrations used clinically. However, lidocaine and tetracaine can be prepared in high concentrations (far exceeding those clinically used) that will produce extensive irreversible neurologic injury and histologic changes. This was also true for sodium bisulfite, an antioxidant used in a number of commercially prepared local anesthetic solutions. Pure solutions of relatively insoluble local anesthetics (bupivacaine and 2-chloroprocaine) failed to produce comparable neurologic or neuropathologic changes when tested at concentrations up to their solubility limits. Extensive neurologic impairment was not necessarily accompanied by equally extensive lesions in the spinal cord and nerve roots.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The effects of a continuous infusion of etomidate on cerebral function, metabolism, and hemodynamics and on the systemic circulation were examined in six dogs. The infusion rate of etomidate was progressively increased at 20-min intervals from 0.02 to 0.4 mg · kg−1· min−1for 2 h. Cerebral oxygen consumption (CMRO2) decreased until there was cessation of neuronal function as reflected by the onset of an isoelectric EEG. This occurred during an infusion of 0.3 mg · kg−1· min−1etomidate when the animals had received a total of 10.7 mg · kg−1over 91 min. At this time the CMRO2was 2.6 ml · min−1· 100 g−1, 48% of control. Thereafter, despite continued administration of etomidate to a total dose of 21.4 mg · kg−1CMRO2did not decrease further. Cerebral blood flow (CBF) decreased in association with a marked increase in cerebrovascular resistance but was independent of changes in CMRO2CBF decreased precipitously from 145 ± 23 to 72 ± 6 ml · min−1· 100 g−1during the lowest infusion rate of 0.02 mg · kg−1· min−1etomidate and stabilized at 34–36 ml · min−1· 100 g−1during an infusion rate of 0.1 mg · kg−1· min−1· CBF remained at this level despite the continued administration of etomidate and a further decrease in CMRO2· Etomidate produced physiologically minor but statistically significant changes in the systemic hemodynamic variables. Assays of cerebral metabolites taken at the end of the infusion revealed a normal energy state and a very mild but significant increase in cerebral lactate to 1.49 μmol · g−1. We conclude that etomidate is a potent, direct cerebral vasoconstrictor that appears to be independent of its effect on CMRO2and that the cerebral metabolic effects of etomidate are secondary to its effect on neuronal function, with little if any direct or toxic effects on metabolic pathways.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

To evaluate the effect of Bicitra® (Willen Drug Company, Baltimore, Maryland), a commercial preparation of sodium citrate and metoclopramide, on gastric contents 150 elective outpatients allocated into six groups with 25 patients in each group were studied. Patients in Group 1 served as controls. Patients in Groups 2, 3, 5, and 6 received Bicitra®, po, either 15 ml (Groups 2 and 5) or 30 ml (Groups 3 and 6). In addition, patients in Groups 5 and 6 also received metoclopramide 10 mg, iv; Group 4 patients received metoclopramide 10 mg, iv. Eighty-eight per cent of patients in the control group had a gastricpH ≤ 2.5, while 36% had a gastric content volume ≥ 25 ml withpH ≤ 2.5. Bicitra®, 15 ml and 30 ml, po, increased mean gastricpH and decreased the proportion of patients with a gastricpH ≤ 2.5 to 32 and 16%, respectively, in Groups 2 and 3. However, Bicitra® 15 ml and 30 ml, increased the mean gastric volume in Group 3 and also increased the proportion of patients with a gastric volume ≥ 25 ml to 56% in Group 2 and 84% in Group 3. The addition of metoclopramide 10 mg, iv, to Bicitra® reduced the proportion of patients with a gastric volume ≥ 25 ml in Groups 5 and 6 to 28 and 36%, respectively. Metoclopramide (Group 6) independently reduced mean gastric volume (15.6 mlvs.32.7 ml) and the proportion of patients with a gastric volume ≥ 25 ml (20%vs36%). Bicitra® and metoclopramide combination significantly reduced the proportion of patients with gastric contents ≥ 25 ml withpH ≤ 2.5.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Controversy persists surrounding the relative safety of bupivacaine compared with lidocaine especially with regard to its cardiovascular toxicity and the ability to resuscitate following such occurrences. The margin of safety between seizure onset and cardiovascular collapse was compared in lightly anesthetized and ventilated cats given an equipotent infusion of either lidocaine or bupivacaine (N = 10 for each group). The infusion rates were 4 mg · kg−1· min−1bupivacaine or 16 mg · kg−1· min−1lidocaine. Onset of electrical seizure activity occurred at about the same time in both groups and was defined as the central nervous system (CNS) toxic end point. The infusion continued until the mean arterial pressure reached 10 mmHg (cardiotoxic end point). Despite the early occurrence of electrocardiographic changes in the bupivacaine group, mean arterial pressure was greater and sustained significantly longer (4.9 ± 1.3 min; mean ± SD) with this drug compared with lidocaine (3.0 ± 0.6 min) (P< 0.005). Using the blood pressure criterion for defining cardiovascular (CV) collapse, the CV/CNS toxicity ratio for drug dosage was 4.0 with lidocaine and 4.8 with bupivacaine. The use of a standardized resuscitation protocol made it possible to compare the ability to resuscitate animals in each group. Despite very high plasma local anesthetic concentrations, all lidocaine-infused animals were quickly resuscitated (4.4 ± 3.0 min; mean ± SD). The resuscitation time for the bupivacaine group (5.4 ± 2.4 min) was similar. Two cats in the bupivacaine group could not be brought to resuscitation criterion, a difference, however, that was not statistically significant.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

It is well known that halothane causes an increase in cerebral blood flow (CBF). In this study the effects of halothane, enflurane, and isoflurane on regional cerebral blood flow (rCBF) in humans were determined in the presence of 70% N2O at a combined MAC concentration of 1.5. CBF was determined in 24 patients from the washout of locally applied133Xenon with the use of an external scintillation. All 24 patients (control n = 6, halothane n = 6, enflurane n = 6, and isoflurane n = 6) were undergoing neurosurgical procedures. All patients were anesthetized with thiopental, fentanyl, droperidol, and 70% N2O in oxygen and paralyzed with pancuronium. The measurements were performed after the dura had been opened and before definitive surgery. The first measurement was done in the absence of any volatile agent, and the wash-out curve was registered for 6 min. The second measurement was done after one of the volatile agents had been added for at least 20 min and had reached a concentration of 0.58% for halothane, 1.14% for enflurane, or 1.0% for isoflurane in the expiratory gases in order to obtain about 1.5 MAC with each volatile anesthetic. The anesthetic concentrations were measured with the Engström multigas analyzer EMMA®. The physiologic variables changed very little throughout the period of observation. Body temperature, heart rate, blood pressure, PaCO2, and PaO2were stable. Ephedrine was used to maintain a stable arterial pressure. At approximately 1.5 MAC, halothane (plus N2O) increased rCBF to nearly three times (166%) the control value, while enflurane induced only a slight increase (35%) in rCBF. Isoflurane caused no increase of rCBF at approximately 1.5 MAC (−5%). The authors conclude that isoflurane may well be a better alternative than halothane or enflurane during neurosurgical operations in patients with increased intracranial pressure.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Regional blood flows and cerebral oxygen consumption (CMRO2) were measured following alcohol withdrawal in alcohol-dependent rats. In addition, the authors tested the ability of midazolam (0.057, 0.575, or 5.75 mg · kg−1) to modify alcohol-induced changes. Rats received a 3-week treatment of dailyad libitumaccess to a liquid diet containing 6.54% ethanol or a sham treatment with the same caloric intake but with white dextrin substituted for alcohol. Regional blood flow was measured 12 h after alcohol withdrawal with radioactive microspheres. Nitrous oxide (70% in oxygen) was used as the control anesthetic. Rats withdrawn from alcohol treatment had significantly increased heart rate, cortical cerebral blood flow (CBF) (39 ± 8%, mean ± SE), and CMRO2(41 ± 9%) compared with shamtreated rats (P< 0.05). Subcortical CBF (49 ± 8%), myocardial (52 ± 18%), and hepatic arterial blood flow (298 ± 47%) also were increased in alcohol-withdrawn rats. Renal blood flow decreased 47 ± 5%, while skeletal muscle and small intestinal blood flow were not significantly different between the two groups. Midazolam infusion decreased CBF, CMRO2, and hepatic arterial blood flow in alcohol-withdrawn rats to similar levels as sham-treated rats and increased renal blood flow in both groups. Skeletal muscle and intestinal tissues showed no change in blood flow in response to midazolam. The authors conclude that midazolam may be effective in lowering blood pressure and brain metabolism and reversing regional blood flow changes produced by alcohol withdrawal in the rat.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The systemic effect of bupivacaine on the control of ventilation was studied in eight ASA I (six male, two female) unpremedicated healthy subjects aged 30–55 yr (mean 43.5 yr) and weighing 59–82 kg (mean 69 kg) after axillary blockade with bupivacaine 0.5% without epinephrine, 3 mg/kg. The slope of the ventilatory response to CO2was significantly increased (P< 0.05) from its control value (1.77 ± 1.03 1 ± min−1· mmHg−1[mean ± SD]) 30 min (+19 ± 32%) and 60 min (+32 ± 37%) after axillary blockade, while plasma bupivacaine levels were 1.65 ± 0.82 and 1.40 ± 0.60 μg/ml, respectively. The correlation between individual plasma bupivacaine levels and the changes in the slope of the ventilatory response to CO2was significant (r = 0.57, n = 16,P< 0.05). Resting minute ventilation and end-tidal CO2values did not change significantly. These results suggest that bupivacaine has a systemic stimulating effect on the ventilatory control mechanisms.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID