Balanced pre-emptive analgesia: does it work? A double-blind, controlled study in bilaterally symmetrical oral surgery.
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We studied 32 patients undergoing bilateral symmetrical lower third molar surgery under general anaesthesia to determine if the combined effects of pre-emptive local anaesthetic block using 0.5% bupivacaine, together with i.v. tenoxicam and alfentanil had any benefits over postoperative administration. Patients acted as their own controls and were allocated randomly to have surgery start on one side, the second side always being the pre-emptive side. Difference in pain intensity between the two sides was determined using visual analogue scales completed by each individual at 6 h, and at 1, 3 and 6 days after operation. A long-form McGill pain questionnaire was also used to assess difference in pain intensity between the two sides on the morning after surgery. There was no significant difference in pain intensity at any time after surgery. Our findings indicate that the combined use of pre-emptive analgesia from 0.5% bupivacaine, tenoxicam and alfentanil did not reduce postoperative pain intensity in patients undergoing molar exodontia. (+info)
Intranasal midazolam for premedication of children undergoing day-case anaesthesia: comparison of two delivery systems with assessment of intra-observer variability.
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Midazolam is often used for paediatric premedication. We have compared two methods of administering midazolam intranasally in 44 surgical day-case children allocated randomly to receive midazolam 0.2 mg kg-1 as drops or midazolam 0.1 mg kg-1 from an intranasal spray device. Behaviour was recorded on a four-point scale by the parent, nurse and anaesthetist. Coefficients were obtained representing the change in behaviour score. There was no significant difference in method of administration (coefficient 0.13, P = 0.39). Children were significantly more distressed at the time of premedication and at the time of venous cannulation (coefficients 1.31 and 0.70) than at baseline. There was no significant difference in the assessments between observers. Midazolam by either method was equally effective but acceptability of the premedication was poor in both groups. Intranasal midazolam cannot be recommended as a method for routine premedication of young children. (+info)
Comparison of recovery of propofol and methohexital sedation using an infusion pump.
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Two sedative anesthetic agents administered by an infusion pump were compared during third molar surgery. Forty American Society of Anesthesiologists (ASA) class I or II volunteers were randomly allocated to two groups. All subjects received supplemental oxygen via a nasal hood, fentanyl (0.0007 mg/kg intravenous [i.v.] bolus), and midazolam (1 mg/2 min) titrated to effect. Patients then received either 0.3 mg/kg of methohexital or 0.5 mg/kg of propofol via an infusion pump. Upon completion of the bolus, a continuous infusion of 0.05 mg/kg/min methohexital or 0.066 mg/kg/min propofol was administered throughout the procedure. Hemo-dynamic and respiratory parameters and psychomotor performance were compared for the two groups and no significant differences were found. The continuous infusion method maintained a steady level of sedation. Patients receiving propofol had a smoother sedation as judged by the surgeon and anesthetist. (+info)
Change in pain threshold by meperidine, naproxen sodium, and acetaminophen as determined by electric pulp testing.
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The purpose of this study was to compare changes in pain threshold caused by meperidine, naproxen sodium, acetaminophen, and placebo. The change in pain threshold was measured by electric pulp testing. Acetaminophen elevated the pain threshold statistically significantly. Clinically, however, the superiority of acetaminophen is questionable. No elevation of the pain threshold occurred with narcotic drugs or with nonsteroidal anti-inflammatory drugs: our research shows that the electric pulp tests of patients who have taken these drugs preoperatively will have results similar to those of patients who have taken no drugs. We question the philosophy of administering these drugs for change in pain threshold at the levels used here preoperatively. (+info)
Premedication with melatonin: a double-blind, placebo-controlled comparison with midazolam.
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We have evaluated the perioperative effects of melatonin with those of midazolam in 75 women in a prospective, randomized, double-blind, placebo-controlled study. Patients were given sublingual midazolam 15 mg, melatonin 5 mg or placebo, approximately 100 min before a standard anaesthetic. Sedation, anxiety and orientation were quantified before, and 10, 30, 60 and 90 min after premedication, and 15, 30, 60 and 90 min after admission to the recovery room. Psychomotor performance was evaluated at these times also, using the digit-symbol substitution test (DSST) and the Trieger dot test (TDT). Patients who received premedication with either midazolam or melatonin had a significant decrease in anxiety levels and increase in levels of sedation before operation compared with controls. Midazolam produced the highest scores for sedation at 30 and 60 min after administration and significant psychomotor impairment in the preoperative period compared with melatonin or placebo. After operation, patients who received midazolam or melatonin premedication had increased levels of sedation at 30 min and impairment in performance on the DSST at 15, 30 and 90 min compared with controls. There were no significant differences between the three groups for anxiety levels or TDT performance after operation. Amnesia was notable only in the midazolam group for one preoperative event (entry into the operating room). Patient satisfaction was noted in the midazolam and melatonin groups only. We have demonstrated that melatonin can be used effectively for premedication of adult patients. (+info)
Epileptiform electroencephalogram during mask induction of anesthesia with sevoflurane.
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BACKGROUND: Sevoflurane is suggested as a suitable anesthetic agent for mask induction in adults. The authors recently found that hyperventilation during sevoflurane-nitrous oxide-oxygen mask induction is associated with cardiovascular hyperdynamic response. We tested the hypothesis that the hyperdynamic response can be explained by electroencephalography (EEG) findings. METHODS: Thirty women were randomly allocated to receive sevoflurane-nitrous oxygen-oxygen mask induction using a single-breath method, followed by either spontaneous breathing (n = 15) or controlled hyperventilation (n = 15) for 6 min. EEG was recorded. Blood pressure and heart rate were recorded at 1-min intervals. RESULTS: Epileptiform EEG activity (spikes or polyspikes) was seen in all patients with controlled hyperventilation, and in seven patients with spontaneous breathing (P < 0.01). Jerking movements were seen in three patients with controlled hyperventilation. In the controlled hyperventilation group, heart rate increased 54% from baseline at 4 min after induction (P < 0.001). Mean arterial pressure increased 17% (P < 0.05), peaking at 3 min. In the spontaneous breathing group, heart rate showed no change, and mean arterial pressure decreased by 14% (P < 0.01) at 6 min. Heart rate and mean arterial pressure differed significantly between the groups from 2 min after beginning of the induction to the end of the trial. An increase in heart rate of more than 30% from baseline always was associated with epileptiform EEG activity. CONCLUSIONS: Sevoflurane mask induction elicits epileptiform EEG patterns. These are associated with an increase in heart rate in patients with controlled hyperventilation and also during spontaneous breathing of sevoflurane. (+info)
Evaluation of neuromuscular and cardiovascular effects of two doses of rapacuronium (ORG 9487) versus mivacurium and succinylcholine.
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BACKGROUND: This study compares the neuromuscular blocking and cardiovascular effects of rapacuronium (ORG 9487), a new aminosteroid nondepolarizing muscle relaxant, to recommended intubating doses of succinylcholine and mivacurium. METHODS: Adult patients were randomized in an open-label fashion to receive 1-5 microg/kg fentanyl before 1.5 mg/kg propofol induction followed by 1.5 or 2.5 mg/kg rapacuronium, 1.0 mg/kg succinylcholine, or 0.25 mg/kg mivacurium (i.e., 0.15 mg/kg followed by 0.1 mg/kg 30 s later). RESULTS: Patient neuromuscular blockade status was monitored by measuring the train-of-four response to a supramaximal stimulus at the ulnar nerve every 12 s. Percentage of the first twitch of the train-of-four (T1) at 60 s was similar in patients receiving 1.5 mg/kg rapacuronium, 2.5 mg/kg rapacuronium, and succinylcholine and was significantly less than in patients in the mivacurium group (26, 16, and 18%, respectively, vs. 48%; P < 0.01). Times to 80% T1 depression were also similar among patients in the 1.5 mg/kg rapacuronium, 2.5 mg/kg rapacuronium, and succinylcholine groups and significantly longer in the mivacurium group (62, 54, and 54 s, respectively, vs. 112 s; P < 0.01). Clinical duration was longer in all groups compared with the succinylcholine group; however, clinical duration in the 1.5 mg/kg rapacuronium group was shorter compared with the mivacurium group (15 vs. 21 min, respectively; P < 0.01). Heart rate changes were mild in the 1.5 mg/kg rapacuronium, succinylcholine, and mivacurium groups. The patients in the 2.5 mg/kg rapacuronium group had significantly higher heart rates compared with patients in the mivacurium group. No differences were found in blood pressure changes among patients in the four groups. CONCLUSIONS: Rapacuronium, 1.5 and 2.5 mg/kg, produced neuromuscular blockade as rapidly as succinylcholine and significantly faster than mivacurium. Although succinylcholine continued to show the shortest duration, 1.5 mg/kg rapacuronium used a rapid onset and a relatively short duration and may be considered an alternative to succinylcholine. (+info)
Closed-loop control of propofol anaesthesia.
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We describe the use of a closed-loop system to control depth of propofol anaesthesia automatically. We used the auditory evoked potential index (AEPindex) as the input signal of this system to validate it as a true measure of depth of anaesthesia. Auditory evoked potentials were acquired and processed in real time to provide the AEPindex. The AEPindex was used in a proportional integral (PI) controller to determine the target blood concentration of propofol required to induce and maintain general anaesthesia automatically. We studied 100 spontaneously breathing patients. The mean AEPindex before induction of anaesthesia was 73.5 (SD 17.6), during surgical anaesthesia 37.8 (4.5) and at recovery of consciousness 89.7 (17.9). Twenty-two patients required assisted ventilation before incision. After incision, ventilation was assisted in four of these 22 patients for more than 5 min. There was no incidence of intraoperative awareness and all patients were prepared to have the same anaesthetic in future. Movement interfering with surgery was minimal. Cardiovascular stability and overall control of anaesthesia were satisfactory. (+info)