ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

To determine if thiopental reduces the incidence of neurologic sequelae after coronary artery surgery, we prospectively studied 300 patients undergoing coronary artery bypass grafting. Patients who had no history of neurologic or psychiatric illness were randomly assigned to receive either a thiopental infusion or a saline placebo infusion beginning with the administration of heparin and ending just after aortic decannulation. The patients received an opioid-relaxant anesthetic administered by an anesthesiologist who was not involved in this investigation and who was blinded to the test infusion. One of the investigators infused either saline or thiopental to produce an isoelectric electroencephalogram with 30–45 s between bursts. Standardized neurologic examinations were performed pre-operatively and on the 2nd and 5th postoperative days by one of the blinded investigators. The group of patients receiving thiopental required a longer time for awakening (6.4 ± 3.9vs4.0 ± 2.4 h, mean ± SD,P< 0.05) and for tracheal extubation (22.4 ± 18.4vs11A ± 9.6 h,P< 0.05), and a greater number of these patients were lethargic on the 2nd postoperative day. More patients receiving thiopental required vasoconstrictors during the thiopental loading and cardiopulmonary bypass (CPB) periods, while a greater number of patients receiving placebo required vasodilators. A greater number of patients receiving thiopental required inotropic drugs during separation from CPB. Despite the above differences, only 2 of the 151 patients in the placebo group (1.3%) and 5 of the 149 patients in the thiopental group (3.3%) experienced strokes (P= 0.2535). There were no differences between the groups in time to discharge from the intensive care unit (ICU), length of hospitalization, or hospital costs. The results support the conclusion that thiopental does not reduce the number of strokes in patients undergoing coronary artery surgery.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The neuromuscular effects of desflurane administered alone were studied in ten healthy human volunteers aged 20–27 yr. Also, the dose-response relationships of pancuronium and succinylcholine in surgical patients during anesthesia with desflurane (n = 13) were compared to those during isoflurane anesthesia (n = 14). In the volunteers, we measured the mechanical response of the adductor pollicis muscle to stimulation of the ulnar nerve in a train-of-four (TOF) sequence at 2 Hz and at tetanic frequencies of 50, 100, and 200 Hz, each administered for 5 s. Amplitudes of the first response (T1) in each TOF sequence and the ratios of the fourth TOF response (T4) to the first were similar at 3,6, and 9% desflurane and decreased significantly only at 12% (P< 0.05). Desflurane concentrations of 3–12% caused tetanic fade (>10% decrement in amplitude) at 50, 100, and 200 Hz. The addition of N2O and the duration of anesthetic exposure did not alter desflurane's neuromuscular effects. The only neuromuscular variable influenced by CO2was T1 amplitude, which decreased as arterial CO2tension (PaCO2) increased. The doses of pancuronium that depressed T1 amplitude by 50% (ED50) were similar during anesthesia with 1.25 MAC desflurane, 10.5 ± 2.8 μg/kg (mean ± SD) and 1.25 MAC isoflurane, 12.3 ± 5.0 μg/kg. The ED50doses of succinylcholine were similar during anesthesia with desflurane 132 ± 76 μg/kg and isoflurane 123 ± 36 μg/kg. We conclude that desflurane significantly depresses neuromuscular function and augments the action of pancuronium and succinylcholine to a degree similar to that of isoflurane.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Thirty-eight healthy outpatients undergoing elective surgical procedures lasting 1–3 h were randomly assigned to receive either desflurane 3% (approximately 0.5 MAC) or isoflurane 0.6% (approximately 0.5 MAC) for maintenance of general anesthesia with nitrous oxide 60% in oxygen after a standardized induction sequence consisting of fentanyl 3 μ·kg−1, thiopental 4 μ·kg−1, and succinylcholine 1–1.5μ·kg−1, intravenously. Although anesthetic conditions were similar during operations in the two treatment groups, significant differences were noted in the recovery profiles as measured by elimination kinetics, psychometric testing, and visual analog scales (to assess subjective feelings). The time required for the end-tidal concentration to decrease by 50% was 2.5 ± 0.8 min for desfluranevs9.5 ± 3.4 min for isoflurane (mean ± standard deviation [SD]). Times to awakening and ability to follow simple commands were significantly shorter after desflurane than after isoflurane (5.1 ± 2.4vs10.2 ± 7.7 min 6.5 ± 2.3 minvs11.1 ± 7.9 min, respectively). Postoperatively, patients who received desflurane exhibited less impairment of cognitive function (as measured using the Digit-Symbol Substitution Test) than did those who received isoflurane. Furthermore, visual analog scores indicated that patients receiving desflurane experienced significantly less discomfort (pain), drowsiness, fatigue, clumsiness, and confusion in the early postoperative period. We conclude that desflurane may offer clinical advantages over isoflurane when used for maintenance of anesthesia during outpatient surgical procedures.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

In order to examine the clinical potential of desflurane (difluo-romethyl-l-fluoro-2,2,2-trifluoroethyl ether) in humans, a randomized, controlled study was designed to compare time of emergence from anesthesia in patients undergoing elective surgery under desflurane anesthesia to that of patients under isoflurane anesthesia. Twenty-eight patients were randomly divided into four groups. Group 1 received isoflurane 0.65 MAC; group 2, desflurane 0.65 MAC; group 3, isoflurane 1.25 MAC; and group 4, desflurane 1.25 MAC. Anesthesia was induced with sodium thiopental, and N2O 60% was added to the volatile agent. Mean anesthetic exposure times (min [mean ± SD]) were 108 ± 49 in group 1, 132 ± 46 in group 2, 147 ± 74 in group 3, and 166 ± 71 in group 4, with no significant differences between groups. The times from discontinuation of anesthetic gases until patients opened their eyes and squeezed the investigator's hand in response to a command were averaged and recorded as “emergence time.” Emergence time was significantly less with desflurane than with isoflurane given at the same MAC. Patients receiving isoflurane 0.65 MAC responded to commands 15.6 ± 4.3 min after discontinuation of the anesthetic; patients in the desflurane 0.65 MAC group responded in 8.8 ± 2.7 min (P< 0.01). Emergence time for isoflurane 1.25 MAC was 30.0 ± 11.0 min; for desflurane 1.25 MAC it was 16.1 ± 6.0 min (P< 0.05). Our results confirm that emergence from desflurane anesthesia is more rapid than from isoflurane.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Desflurane (formerly I-653) is a new inhalaticnal anesthetic with a promising pharmacokinetic profile that includes low solubility in blood and tissue, including fat. Since its lipid solubility is less than that of other volatile agents, it may have lower potency. Low solubility would be expected to increase the rate at which alveolar concentration approaches inspired concentration during induction as well as to increase the rate of elimination of desflurane from blood at emergence. We determined the minimum alveolar concentration (MAC) of desflurane in 44 unpremedicated ASA physical status 1 or 2 patients undergoing elective surgery. We prospectively studied four patient groups distinguished by age and anesthetic regimen: 18–30versus31–65 yr and desflurane in 60% N2O/40% O2versusdesflurane in O2. Anesthesia was induced with desflurane or desflurane in 60% N2O/40% O2. MAC was determined by a modification of Dixon's up-and-down method with increments of 0.5% desflurane. The MAC of desflurane in O2was 7.25 ± 0.0 (mean ± SD) in the 18–30-yr age group, and 6.0 ± 0.29 in the 31–65-yr group; the addition of 60% N2O reduced the MAC to 4.0 ± 0.29 and 2.83 ± 0.58, respectively. The median time from discontinuation of desflurane to an appropriate response to commands was 5.25 min. Desflurane appears to be a mild airway irritant but was well tolerated by all patients.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The electroencephalographic (EEG) effects of a new inhaled anesthetic are of interest because of the potential of such agents to produce excitatory (convulsant) activity and because of the potential usefulness of the EEG as an indicator of anesthetic depth and cerebral activity. Accordingly, we examined the EEG in 12 healthy, young male volunteers during desflurane anesthesia. Each subject had a baseline recording and then steady-state exposure to 6, 9, and 12% (0.83, 1.24, and 1.66 MAC) desflurane in O2alone, and to 3, 6, and 9% desflurane in O2with 60% N2O. The sequence of doses and the presence of N2O were randomized. We used mechanical ventilation to maintain normocapnia at each dose level. We also tested the effects of hypercapnia secondary to spontaneous ventilation. Additionally, at 1.24 MAC, subjects' lungs were hyperventilated to a Pco2, of 25.8 ± 0.7 mmHg and exposed to rhythmic, loud clapping to attempt to provoke excitatory phenomena. Finally, after at least 6 h exposure to desflurane, we repeated measurements at 0.83 and 1.66 MAC to assess possible tolerance. Four channels of EEG were monitored visually, and at each dose, a quantitative EEG analysis was performed. Desflurane produced EEG changes comparable to those observed with equipotent levels of isoflurane. No epileptiform activity was seen. Desflurane significantly suppressed EEG activity; prominent burst suppression was seen at 1.24 MAC and higher. Substitution of N2O for 0.42 MAC desflurane reduced the degree of EEG suppression relative to the equipotent administration of desflurane and O2. Quantitative EEG measures for the early doses and for the later, repeated exposures did not differ.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Unsuspected distal migration of the tip of the pulmonary artery catheter may cause life-threatening complications. We prospectively evaluated the clinical utility of the PA Watch Catheter® in 25 patients after cardiac surgery by hourly measurements of pulmonary artery (distal lumen), right ventricular (middle lumen), and central venous (proximal lumen) pressures. The catheter was considered to be in the proper position when the middle lumen port, located 10 cm from the tip, transmitted a right ventricular pressure waveform. Satisfactory initial catheter placement was obtained in 24 of 25 patients. During the 28.4 ± 1.8 h of postoperative monitoring, clinically unsuspected distal catheter migration, indicated by the presence of a pulmonary artery pressure waveform in the middle lumen port, occurred in 12 of the 25 patients (48%). In these patients, 20 episodes occurred and required catheter withdrawal distances of 1.8 ± 0.3 cm (range 1–6 cm). The PA Watch Catheter® proved to be a useful indicator of unsuspected distal catheter migration in the postoperative period. The PA Watch Catheter® allows assessment of catheter tip placement in the proximal pulmonary artery and may decrease catheter-induced complications.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Several groups of investigators have reported that the plasma concentrations of laudanosine, a metabolite of atracurium, are high immediately after administration of atracurium and thereafter decline. Such a time profile of a metabolite in plasma is very unusual. The authors describe a model of atracurium decay and laudanosine disposition that satisfactorily explains these data. The model reveals the following: 1) each atracurium molecule is degraded into two of laudanosine; 2) the generation of laudanosine occurs through two processes—a rapid one, involving approximately 31% of the atracurium dose and proceeding with a half-life of 0.25 min, and a slower one, involving the residual 69% and proceeding with a half-life of 51 min; 3) atracurium degradation by Hofmann elimination proceeds in the central and the noncentral compartments; 4) laudanosine formed from atracurium gains access to its central compartment and disappears from plasma in a biexponential pattern; 5) in cirrhotic patients, only 18% of the atracurium dose is degraded rapidly and laudanosine is disposed of more slowly. The authors propose that the rapid degradation of atracurium in plasma proceeds through a nucleophilic substitution reaction, with plasma nucleophiles substituting for the laudanosine moiety in atracurium. Because both laudanosine moieties in atracurium are required to establish and sustain plasma concentrations of laudanosine, excretion of atracurium or its degradation through pathways not generating laudanosine must be small.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID