ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

Mouth opening and the resistance to opening developed by the muscles of mastication were measured in 63 children anesthetized with halothane and relaxed with succinylcholine, pancuronium, or vecuronium. Measurement of mouth opening, induced by a constant test force, was made when each patient was deeply anesthetized, as judged by clinical parameters. Succinylcholine, vecuronium, or pancuronium was then administered. The mouth opening measurement was repeated immediately after the loss of limb muscle twitch response and 45 s following the loss of twitch response. For the 24 patients receiving succinylcholine, there was a significant reduction in mean mouth opening (P< 0.0001) and a significant increase in jaw stiffness (P< 0.0001) immediately after limb relaxation. Forty-five seconds after full limb relaxation was attained, the mean mouth opening was still reduced (p< 0.0001) and the mean jaw stiffness was still increased (p< 0.0003) in the succinylcholine group. Patients receiving cither vecuronium or pancuronium did not show a significant change of mouth opening or jaw stiffness following limb relaxation. Three patients, who received succinylcholine, required several attempts at tracheal intubation due to increased resistance to mouth opening. Anesthesia and surgery proceeded in all patients. None of the patients developed malignant hyperthermia. In view of the fact that a reduction in mouth opening was a constant finding when succinylcholine was administered during halothane anesthesia, the assumption that isolated “masseter spasm” or jaw stiffness heralds malignant hyperthermia should be reconsidered.

ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The first pass uptake of fentanyl, meperidine, and morphine in human lung was studied in patients using a double indicator dilution technique. A bolus containing one of the drugs and indocyanine green dye (ICG) was rapidly injected into the central venous catheter of patients prior to anesthesia for surgery. Sequential arterial blood samples were collected at 1-s intervals for 45 s after injection. The total amount of drug taken up by the lung during the first pass and the instantaneous extraction of drug at each time point during the first pass were calculated from the differences in the arterial blood concentrationversustime curves of the nondiffusible indicator (ICG) and the drug. The total uptake (mean ± SE) during the first pass through the human lung for fentanyl and meperidine was 75.2 ± 3.2% and 64.7 ± 7.8% of the injected dose, respectively. The pulmonary uptake of morphine was very small, with 96.5 ± 7.1% of the injected dose recovered in arterial blood after the first pass through the lung. The arterial blood concentration of drug and dyeversustime showed a slight delay of the fentanyl and meperidine peaks compared to ICG, It was also observed that greater than 90% of these drugs were extracted from the blood in the early part of the first pass, but the extraction decreased with time during the first pass through the lung. These findings indicate that sonic of the drug taken up by the lung can diffuse back out into the blood. In spite of this back diffusion, 75% and 65% of the fentanyl and meperidine remained in the lung tissue at the end of the first pass. This high first pass pulmonary uptake of fentanyl and meperidine results in a large decrease in the amount of drug that enters the systemic circulation immediately after injection. This non-respiratory pulmonary function could play a major role in determining the plasma pharmacokinetics of these drugs immediately after intravenous administration. No such role of the lung exists for morphine.

ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The effects of intravenous droperidol, 0.2 mg·kg-1, on baroreflex control of heart rate and on plasma catecholamine levels were determined in 10 ASA physical status I unpremedicated patients. Baroreflex control of heart rate was assessed by a pressor test using phenylephrine. Plasma concentrations of norepinephrine and epinephrine were determined by high pressure liquid chromatography, and plasma droperidol concentrations were measured by radioimmunoassay, from blood samples withdrawn before baroreflex evaluation. All data were obtained before and 5, 10, and 15 min following droperidol administration. Baroreflex response was significantly decreased after droperidol at each time of the study with the maximal decrease (-47% from control) observed at 5 min. No resetting of baroreflex was present since the pulse interval at the reference pressure was unchanged. Plasma norepinephrine concentrations were moderately but significantly increased only at 5 min, while no significant change in epinephrine concentrations was observed. It is concluded that droperidol induces a moderate but sustained alteration of baroreflex function and a transient increase in plasma norepinephrine concentrations.

ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The potential clinical scope of use-dependent block of conduction (UDB) was assessed by studying characteristics of UDBin vitroin individual mammalian axons. Single and repetitive stimulation was applied to rabbit cervical sympathetic and vagus nerves exposed to solutions containing lidocaine 0, 0.3, or 0.6 niinol/1 (9.1 or 18.2 mg/dl) at 37° C. Unit responses were recorded in dissected filaments or extracellularly in the vagus nodose ganglion. With lidocaine 0.3 mM, equilibrium conduction block, tested by single shocks, was rare. 40-Hz trains produced a significantly greater increase in latency (slowing of conduction) and a much greater incidence of UDB in the sympathetic units than in myclinated vagus axons of equivalent control conduction velocities or in unmyclinated axons. 10-Hz stimulation did not produce UDB. With lidocaine 0.6 mM, the incidence of equilibrium conduction block was too high among sympathetic axons to assess UDB, and significantly higher than among nonsympathetic myclinated and unmyclinated units. The observations support the hypothesis that the differential block of sympathetics observed clinically with spinal anesthesia may be, at least in part, a use-dependent (frequency-dependent) effect. UDB seems unlikely to contribute to local anesthetic block of pain impulses.

ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

Calcium entry blocking drugs (CaEBs) produce vasodilation and, in high doses, modify alpha adrenergic receptor function. Previous laboratory data suggested that CaEBs might alter the response to α-adrenergic stimulation. The authors tested the hypothesis that CaEB therapy altered α-adrenergic responsiveness in patients chronically treated with CaEBs. Twenty-six consenting patients with coronary artery disease were given a phenylephrine challenge before anesthesia induction and during cardiopulmonary bypass while the aorta was cross-clamped. A log dose response curve was constructed for each patient, and the ED30(dose producing 30% increase in systemic vascular resistance) was calculated. Nine patients not treated with CaEB served as controls, and 17 patients were treated with nifedipine (n = 7) or diltiazem (n = 10). Mean ED30 was increased approximately three-fold in the CaEB treated groups compared to the control group. However, there was no statistical difference in the KD30 or phenylephrine dose response slopes between CaEB treated and untreated patients. In awake patients, ED30correlated with nifedipine levels (R = 0.953,P= 0.01). There was a significant (P≤ .02) shift in the ED30from prior to anesthesia (o during aortic cross-clamp and cardiopulmonary bypass; ED30was approximately 50% less and correlated with CaEB level (R = 0.713,P= 0.03). Hemodynainic variables were not different between groups at any interval. Our data suggest that vascular responsiveness lo phenylephrine in patients treated with CaEBs is diminished, but similar to that in untreated patients. Vascular responsiveness decreases in awake patients with increasing nifedipine levels.

ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The effects of short-term infusion (10 min) of nifedipine (7.5 μ·kg-1) or verapamil (0.15 mg·kg-1) on left ventricular (LV) contractility and on systemic hemodynamics in patients with coronary artery disease, chronically treated with low-dose β-adrenergic blocking drugs, exhibiting a normal LV function at rest, arc presented. In order to analyze the interaction between calcium entry blocking drugs and halothane, the results arc discussed in light of data, obtained in similar patients during halothane anesthesia, using identical experimental conditions, which have already been reported. LV dP/dtmaxand LV end-diastolic pressure (LVEDP) remained unaffected when nifedipine was infused in the awake patients. Verapamil significantly decreased LV dP/dtmaxin patients while awake, but LVEDP did not change. Both calcium entry blocking drugs caused decreases in blood pressure and systemic vascular resistance, accompanied by increases in heart rate. The only significant differences between the awake and the anesthetized patients were the absence of changes in heart rate and the greater reduction in LV dP/dtmaxfollowing administration of the calcium entry blocking drugs during anesthesia. Possible explanations for this may include the drugs' combined interference with calcium ion fluxes within the myocardial and smooth muscle fibers, the ability of halothane to modify the response of the autonomic nervous system to the calcium entry blocking drugs and altered kinetics of the calcium entry blocking drugs induced by the volatile anesthetic. It is impossible to determine from the present investigation which of these mechanisms is predominant.

ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

Systolic pressure variation (SPV) is defined as the difference between the maximum and minimum values of systolic blood pressure following a single positive pressure breath. An increase in the SPV is known to occur clinically during hypovolemia. This study aims to quantify SPV during graded hemorrhage in ventilated dogs, and to compare its reliability relative to other hemodynamic indicators of hypovolemia. Ten anesthetized dogs were mechanically ventilated with a fixed tidal volume. A continuously inflated vest was applied around the chest to maintain the ratio of lung to chest wall compliance similar to that of humans (0.83 ± 0.12). SPV was further divided into δ up and δ down components relative to apneic (5 s) systolic blood pressure. Dogs were bled 5, 10, 20, and 30% of their estimated blood volume. The measured parameters best correlated to the amount of bleeding were SPV (ra, = 0.993), δ down (ra, = 0.981), and cardiac output (ra, = 0.976). The SPV and its δ down component correlated to the degree of hemorrhage as well as the CO and the pulmonary capillary wedge pressure, and significantly better than the central venous pressure and the mean systemic blood pressure. Thus, SPV and its δ down component arc accurate indicators of hypovolemia in ventilated dogs subjected to hemorrhage.

ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The authors studied the effects of enflurane, isoflurane, and fentanyl, each in combination with 60% nitrous oxide, on the vecuronium infusion rate necessary to maintain constant 90% depression of control muscle twitch tension. Thirty healthy surgical patients were given an initial 0.1 mg/kg bolus of vecuronium, followed by an infusion of vecuronium at an initial rate of 1.0 μg·kg-1·min-1·After 1 h of steady-state 90% twitch depression, plasma vecuronium concentrations (Css90) were measured by capillary column gas chromatography. Total plasma clearance of vecuronium was estimated using Cs59n values. Vecuronium infusion rates (mean ± SD) were similar for patients given enflurane (0.28 ± 0.13 μg·kg-1min-1) and isoflurane (0.30 ± 0.13 μg·kg-1·min-1), but significantly higher in patients given fentanyl (0.92 ± 0.37 μg·kg-1·min-1). Values for Css90in the patients receiving enflurane and isoflurane were similar (71 ± 34 and 72 ± 44 ng/ml, respectively), but significantly higher in those receiving fentanyl (165 ± 48 ng/ml). Total plasma clearance was similar during enflurane, isoflurane, and fentanyl anesthesia (4.4 ± 2.6, 4.6 ± 1.2, and 5.6 ± 1.9 ml·kg-1min-1, respectively). The authors conclude that patients receiving isoflurane and enflurane require markedly lower vecuronium infusion rates to achieve 90% neuromuscular blockade than those receiving fentanyl. The enhancement of neuromuscular blockade by isoflurane and enflurane represents a change in the pharmacodynamics of vecuronium-induced neuromuscular blockade, rather than a change in pharmacokinetics.

ISSN:0003-3022    

出版商:OVID    

年代:1987

数据来源: OVID