ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundHalothane and caffeine diagnostic protocols and an experimental ryanodine test from the North American Malignant Hyperthermia (MH) Group (NAMHG) and the European MH Group (EMHG) have not been compared in the same persons until now.MethodsThe outcomes of the NAMHG and EMHG halothane and caffeine contracture tests were compared in 84 persons referred for diagnostic testing. In addition, the authors assessed the experimental ryanodine protocol in 50 of these persons.ResultsAlthough the NAMHG and EMHG halothane protocols are slightly different methodologically, each yielded outcomes in close (84‐100%) agreement with diagnoses made by the other protocol. Excluding 23 persons judged to be equivocal (marginally positive responders) by the EMHG protocol resulted in fewer persons classified as normal and MH susceptible (42 and 19, respectively) than those classified by the NAMHG protocol (48 and 34, respectively). For the 61 persons not excluded as equivocal, the diagnoses were identical by both protocols, with the exception of one person who was diagnosed as MH susceptible by the NAMHG protocol and as “normal” by the EMHG protocol. The NAMHG protocol produced only two equivocal diagnoses. Therefore, a normal or MH diagnosis by the NAMHG protocol was frequently associated with an equivocal diagnosis by the EMHG protocol. The time to 0.2‐g contracture after the addition of 1 [micro sign] M ryanodine completely separated populations, which was in agreement with the EMHG protocol and, except for one person, with the NAMHG protocol.ConclusionsOverall, the NAMHG and EMHG protocols and the experimental ryanodine test yielded similar diagnoses. The EMHG protocol reduced the number of marginal responders in the final analysis, which may make the remaining diagnoses slightly more accurate for use in genetic studies.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundIn the absence of explicit memories such as the recall and recognition of intraoperative events, memory of auditory information played during general anesthesia has been demonstrated with several tests of implicit memory. In contrast to explicit memory, which requires conscious recollection, implicit memory does not require recollection of previous experiences and is evidenced by a priming effect on task performance. The authors evaluated the effect of a standardized anesthetic technique on implicit memory, first using a word stem completion task, and then a reading speed task in a subsequent study.MethodsWhile undergoing lumbar disc surgery, 60 patients were exposed to auditory materials via headphones in two successive experiments. A balanced intravenous technique with propofol and alfentanil infusions and a nitrous oxide‐oxygen mixture was used to maintain adequate anesthesia. In the first experiment, 30 patients were exposed randomly to one of the two lists of 34 repeated German nouns; in the second experiment, 30 patients were exposed to one of two tapes containing two short stories. Thirty control patients for each experiment heard the tapes without receiving anesthesia. All patients were tested for implicit memory 6‐8 h later: A word stem completion task for the words and a reading speed task for the stories were used as measures of implicit memory.ResultsThe control group completed the word stems significantly more often with the words that they had heard previously, but no such effect was found in the anesthetized group. However, both the control and patient groups showed a decreased reading time of about 40 ms per word for the previously presented stories compared with the new stories. The patients had no explicit memory of intraoperative events.ConclusionsImplicit memory was demonstrated after anesthesia by the reading speed task but not by the word stem completion task. Some methodologic aspects, such as using low frequency words or varying study and test modalities, may account for the negative results of the word stem completion task. Another explanation is that anesthesia with propofol, alfentanil, and nitrous oxide suppressed the word priming but not the reading speed measure of implicit memory. The reading speed paradigm seems to provide a stable and reliable measurement of implicit memory.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundIt is still unclear whether memory of intraoperative events results entirely from moments of inadequate anesthesia. The current study was designed to determine whether the probability of memory declines with increasing depth of the hypnotic state.MethodA list of words was played via headphones during surgery to patients who had suffered acute trauma. Several commonly used indicators of anesthetic effect, including the bispectral index, were recorded during word presentation. First, these indicators served as predictors of the memory performance in a postoperative word stem completion test. Second, general memory performance observed in the first part was separated into explicit and implicit memory using the process dissociation procedure, and then two models of memory were compared: One model assumed that the probability of explicit and implicit memory decreases with increasing depth of hypnotic state (individual differences model), whereas the other assumed equal memory performance for all patients regardless or their level of hypnotic state.ResultsGeneral memory performance declined with decreasing bispectral index values. None of the other indicators of hypnotic state were related to general memory performance. Memory was still significant at bispectral index levels between 60 and 40. A comparison of the two models of memory resulted in a better fit of the individual differences model, thus providing evidence of a dependence of explicit and implicit memory on the hypnotic state. Quantification of explicit and implicit memory revealed a significant implicit but no reliable explicit memory performance.ConclusionsThis study clearly indicates that memory is related to the depth of hypnosis. The observed memory performance should be interpreted in terms of implicit memory. Auditory information processing occurred at bispectral index levels between 60 and 40.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundPatients with essential hypertension show altered baroreflex control of heart rate, and during the perioperative period they demonstrate increased circulatory instability. Clonidine has been shown to reduce perioperative circulatory instability. This study documents changes in measures of heart rate control after surgery in patients with essential hypertension and determines the effects of clonidine on postoperative heart rate control in these patients.MethodsUsing a randomized double‐blind placebo‐controlled design, 20 patients with essential hypertension (systolic pressure > 160 mmHg or diastolic pressure > 95 mmHg for >or= to 1 yr) were assigned to receive clonidine (or placebo), 6 [micro sign]g/kg orally 120 min before anesthesia and 3 [micro sign]g/kg intravenously over 60 min before the end of surgery. The spontaneous baroreflex ("sequence") technique and analysis of heart rate variability were used to quantify control of heart rate at baseline, before induction of anesthesia, and 1 and 3 h postoperatively.ResultsBaroreflex slope and heart rate variability were reduced postoperatively in patients given placebo but not those given clonidine. Clonidine resulted in greater postoperative baroreflex slope and power at all frequency ranges compared with placebo (4.9 +/− 2.9 vs. 2.2 +/− 2.1 ms/mmHg for baroreflex slope, 354 +/− 685 vs. 30 +/− 37 ms2/Hzfor high frequency variability). Clonidine also resulted in lower concentrations of catecholamine, decreased mean heart rate and blood pressure, and decreased perioperative tachycardia and hypertension.ConclusionsPatients with hypertension exhibit reduced heart rate control during the recovery period after elective surgery. Clonidine prevents this reduction in heart rate control. This may represent a basis for the improved circulatory stability seen with perioperative administration of clonidine.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundTo reduce the ambient concentration of waste anesthetic agents, exhaust gas scavenging systems are standard in almost all operating rooms. The incidence of contamination and the factors that may increase the concentrations of ambient anesthetic gases have not been evaluated fully during routine circumstances, however.MethodsConcentrations of nitrous oxide (N2O) in ambient air were monitored automatically in 10 operating rooms in Kagoshima University Hospital from January to March 1997. Ambient air was sampled automatically from each operating room, and the concentrations of N2O were analyzed every 22 min by an infrared spectrophotometer. The output of the N2O analyzer was integrated electronically regarding time, and data were displayed on a monitor in the administrative office for anesthesia supervisors. A concentration of N2O > 50 parts per million was regarded as abnormally high and was displayed with an alarm signal. The cause of the high concentration of N2O was then sought.ResultsDuring the 3‐month investigation, N2O was used in 402 cases. Abnormally high concentrations of N2O were detected at some time during 104 (25.9%) of those cases. The causes were mask ventilation (42 cases, 40.4% of detected cases), unconnected scavenging systems (20 cases, 19.2%), leak around uncuffed pediatric endotracheal tube (13 cases, 12.5%), equipment leakage (12 cases, 11.5%), and others (17 cases, 16.4%).ConclusionsN2O contamination was common during routine circumstances in our operating rooms. An unconnected scavenging system led to the highest concentrations of N2O recorded. Proper use of scavenging systems is necessary if contamination by anesthetic gas is to be limited.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundNausea and vomiting are the most frequent problems after minor ambulatory surgical procedures. The agents used to induce and maintain anesthesia may modify the incidence of emesis. When neuromuscular blockade is antagonized with anticholinesterases, atropine or glycopyrrolate is used commonly to prevent bradycardia and excessive oral secretions. This study was designed to evaluate the effect of atrophine and glycopyrrolate on postoperative vomiting in children.MethodsNinety‐three patients undergoing tonsillectomy with or without adenoidectomy were studied. After inhalation induction of anesthesia with nitrous oxide, oxygen, and halothane, anesthesia was maintained with a nitrous oxide‐oxygen mixture, halothane, morphine, and atracurium. Patients were randomized to receive, in a double‐blinded manner, either 15 [micro sign]g/kg atropine or 10 [micro sign]g/kg glycopyrrolate with 60 [micro sign]g/kg neostigmine to reverse neuromuscular blockade. Patient recovery, the incidence of postoperative emesis, antiemetic therapy, and the duration of postoperative hospital stay were assessed.ResultsThere were no significant differences in age, gender, weight, or discharge time from the postanesthesia care unit or the hospital between the groups. Twenty‐four hours after operation, the incidence of vomiting in the atropine group (56%) was significantly less than in the glycopyrrolate group (81%; P < 0.05). There was no significant difference between the atropine and glycopyrrolate groups in the number of patients who required antiemetics or additional analgesics.ConclusionsIn children undergoing tonsillectomy with or without adenoidectomy, reversal of neuromuscular blockade with atropine and neostigmine is associated with a lesser incidence of postoperative emesis compared with glycopyrrolate and neostigmine.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID