摘要:

To determine the influence of renal function on the pharmacology of atracurium, 10 patients with normal renal function and 10 with renal failure (scheduled for cadaver kidney transplant) were anesthetized with nitrous oxide and halothane. Atracurium besylate, 0.5 mg·kg−1, was given as an iv bolus and plasma samples were collected over a 4-h period. These samples were assayed for atracurium (all patients) and laudanosine, one of the principal metabolites (eight of the normal group), using an ion-exchange liquid chromatographic assay. The plasma concentrations of atracurium for each patient were fitted to a two-compartment pharmacokinetic model. The onset time, duration of action, and recovery time of atracurium neuromuscular blockade were measured. There were no differences found in the pharmacokinetics or pharmacodynamics of atracurium between patients with normal renal function and those with renal failure. There were measurable levels of laudanosine following atracurium administration with peak levels of 199 ± 31 ng·ml−1at 2 min. The authors conclude that the pharmacokinetics and pharmacodynamics of atracurium are not altered by renal failure.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Hypoxemia created by pulmonary microemboli is improved by continuous positive-pressure ventilation (CPPV) but at a cost of reducing cardiac output (&OV0422;). In this high pulmonary vascular resistance (PVR), pulmonary edema setting, the authors attempted to increase the &OV0422;, which had been reduced by CPPV, with an infusion of dextraran. In 14 dogs, 0.125 g/kg of starch microemboli (63–74 μm in diameter) were infused. CPPV at 15 cm H2O then was applied and PaO2increased from 53 ± 4 to 69 ± 3 mmHg, but &OV0422; decreased from 2.9 ± 0.2 to 1.7 ± 0.2 l/min. Seven of these dogs (control group) were monitored for 3 h. In the remaining seven dogs (volume group), dextran 40 was infused until &OV0422; returned to pre-CPPV values, and monitoring was continued for 3 h. With return of &OV0422; to pre-CPPV levels, indices of tissue oxygenation (O2transport, P&OV0456;O2, O2consumption and metabolic acidosis) were significantly improved. However lung water was increased significantly by the volume infusion, so that at 3 h lung water in the volume group was double the value in the control group. The authors conclude that volume infusion in the face of a high PVR may correct the reduced &OV0422; of CPPV and improve tissue oxygenation, but it also may increase pulmonary edema.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

In six dogs, the authors investigated the effect of balothane on cardiac acceleration response to the electrical stimulation of a cutaneous nerve. It was found that increasing the concentration of halothane was associated with a proportional depression of the cardiac acceleration response to somatic nerve stimulation (y—99.8 - 44.3x; y—δHR, x—halothane end-tidal concentration). Relationship of the response to end-tidal anesthetic concentration was characterized by a strong correlation (r = −0.93,P< 0.0001). Complete abolition of the increase in heart rate in response to somatic nerve stimulation was observed at a halothane end-tidal concentration of 2.2 vol% (extrapolation). It is suggested that suppression of heart rate increase to noxious stimulation may be used as a graded index of the depth of anesthesia for halothane.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The biochemical mechanisms by which nitroso-vasodilators cause smooth muscle relaxation remain controversial. One theory states that the effects of nitroso-vasodilators are mediated by increased intracellular levels of cyclic GMP due to activation of guanylate cyclase. To test this hypothesis, the authors examined the effects of sodium nitroprusside (SNP) in anesthetized dogs with and without pretreatment with the phosphodiesterase inhibitor aminophylline. Aminophylline pretreatment resulted in a 2.8-fold potentiation of the hypotensive effects of a continuous infusion of SNP. Potentiation also was seen for the effects of SNP on stroke volume, heart rate, and plasma cyclic GMP levels. These results support the hypothesis that nitroso-vasodilators exert their effects via guanylate cyclase activation. The authors advise caution when vasodilator therapy with agents such as SNP, nitroglycerin, or hydralazine is instituted in patients receiving aminophylline and when aminophylline is either instituted or discontinued in patients on vasodilator therapy.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The respiratory depressant and analgesic effects of intravenous dezocine were evaluated in six healthy volunteers. Single 0.15 mg/kg doses were compared with identical amounts of morphine, and the two drugs were given in combination. Five successive 0.15 mg/kg doses of dezocine also were given to identify dose-effect relationships. Respiratory center sensitivity was monitored by carbon dioxide (CO2) rebreathing and mouth occlusion pressure (P0.1) measurements, while analgesia to experimental pain was tested with submaximal tourniquet ischemia. Single 0.15 mg/kg doses of dezocine produced significantly more tolerance to experimental pain and greater respiratory depression than a comparable dose of morphine in the first hour, but effects of both drugs were similar thereafter. Multiple doses of dezocine progressively increased pain tolerance from 46 ± 14% above control with the first dose to 70 ± 18% above control with the second dose (cumulative total 0.30 mg/kg). Additional dezocine doses did not result in significantly more analgesia. Depression of CO2sensitivity followed a similar pattern. Morphine 0.15 mg/kg, when given to subjects who had received a prior dose of dezocine, produced no additional effect beyond that observed with dezocine. With the reverse sequence, dezocine increased the respiratory depression of morphine but also produced a dramatic increment in analgesia, which suggested an additive action. Dezocine is therefore an effective analgesic with morphine-like effects. In human subjects it appears to be a slightly more potent analgesic than morphine in identical clinical doses (0.15 mg/kg). Dezocine is similar to other agonist-antagonist analgesics in that it exhibits a ceiling effect for respiratory depression that parallels its analgesic activity.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The authors tested in dogs the hypothesis that beta-adrenoceptor blockade might alter the time course or magnitude of serum potassium (K+) changes following the administration of succinylcholine (SCh). The results indicate that the normal increase in K+ induced by SCh (1 mg/kg intravenously) is exaggerated in the presence of propranolol-induced (0.25 mg/kg), beta-adrenoceptor blockade. Specifically, a peak increase of 1.7 mEq/1 (43%) over control K+ was noted in the beta-blocked dogsversusa 0.5 mEq/l (13%) increase in control dogs. The peak increase in K+ occurred later in the beta-blocked dogs (60–90 min post-SCh)versuscontrol dogs (30 min post-SCh). The authors postulate that these results reflect impairment of intracellular uptake of the SCh-induced acute K+ load secondary to beta-adrenoceptor blockade. Additionally, in a third group of dogs, diazepam in a dose of 0.5 mg/kg attenuated the K+ increases (1 mEq/1—24%) following SCh in beta-blocked dogs. Whether these data can be extrapolated to beta-adrenoceptor blocked patients remains a matter for further investigation. In the interim, periodic monitoring of K+ is warranted in any patient receiving medications known to alter the state of activity of the beta-adrenoceptor. In particular, careful consideration must be given to the potential impact of various interventions (SCh administration, K+ infusion) on K+ levels in beta-adrenoceptor blocked patients.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Hepatic arterial blood flow (HABF) and portal blood flow (PBF) were measured in 18 dogs while awake and during isoflurane and halothane anesthesia. Surgical preparation 1 week before the measurements consisted of a left thoracotomy, placement of a left atrial catheter, and insertion of another catheter into the distal aorta via the left femoral artery. Cardiac output and liver blood flow were determined using microspheres at three stages: stage 1—awake state; stage 2—after 45 min of 1 MAC of isoflurane (eight dogs) or halothane (10 dogs) anesthesia; and stage 3—after 45 min of 2 MAC of inhalation anesthesia. Half-life and fractional clearance for indocyanine green (ICG) were determined 1 day before the experiment (awake state), and at the end of stages 2 and 3. Mean arterial pressure (MAP) and cardiac index (CI), as well as PBF, decreased during isoflurane and halothane anesthesia. HABF increased significantly during isoflurane anesthesia, remained unchanged during 1 MAC of halothane anesthesia, and significantly decreased during 2 MAC of halothane anesthesia. Apparently, hepatic oxygen supply was maintained much better during isoflurane than during halothane anesthesia. PBF correlated with CI during halothane (r = 0.97) and, to a certain extent, with MAP during isoflurane (r = 0.66). HABF correlated with CI and MAP during halothane (r = 0.74 and 0.71, respectively) but did not correlate with systemic hemodynamic variables during isoflurane. ICG half-life significantly increased during 1 and 2 MAC of halothane anesthesia. The degree of increase did not correlate with the level of anesthesia or the decrease in total hepatic blood flow. Isoflurane anesthesia was not accompanied by significant changes in ICG half-life. The data suggest that halothane has a more deleterious effect on liver blood flow than does isoflurane and, in addition, interferes with liver cell ability to absorb and excrete ICG.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID