The effects of cigarette smoking on anesthesia.
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Cigarette smoke contains over 4000 substances, some of which are harmful to the smoker. Some constituents cause cardiovascular problems, increasing the blood pressure, heart rate, and the systemic vascular resistance. Some cause respiratory problems, interfering with oxygen uptake, transport, and delivery. Further, some interfere with respiratory function both during and after anesthesia. Some also interfere with drug metabolism. Various effects on muscle relaxants have been reported. Risk of aspiration is similar to that of nonsmokers, but the incidence of postoperative nausea and vomiting appears to be less in smokers than in nonsmokers. Even passive smoking effects anesthesia. Best is to stop smoking for at least 8 weeks prior to surgery or, if not, at least for 24 hours before surgery. Anxiolytic premedication with smooth, deep anesthesia should prevent most problems. Monitoring may be difficult due to incorrect readings on pulse oximeters and higher arterial to end tidal carbon dioxide differences. In the recovery period, smokers will need oxygen therapy and more analgesics. It is time that anesthesiologists played a stronger role in advising smokers to stop smoking. (+info)
Anesthetic choice of halothane versus propofol: impact on experimental perioperative stroke.
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BACKGROUND AND PURPOSE: It is not known whether preischemic exposure to anesthetic agents affects the amount of damage from transient focal ischemia that occurs after cessation of the anesthetic. We compared the effect of prior exposure to halothane or propofol on infarction size after transient middle cerebral artery occlusion (MCAO) induced in the awakening animal to test the hypothesis that anesthetic type and exposure duration would independently affect the amount of brain injury. METHODS: Male Wistar rats (weight, 200 to 300 g) were anesthetized briefly with halothane for placement of hemodynamic instrumentation. Twenty-four hours later, rats were treated with either a short (approximately 1 hour) or long (8 hours) duration of inhaled halothane (1% to 2%) or intravenous propofol (10 mg/kg bolus, 30 mg/kg per hour infusion). Each cohort (n=8 per group) was then subjected to 2-hour MCAO by the intraluminal suture technique. All anesthesia was discontinued once MCAO was achieved. Infarct volume was measured at 22 hours of reperfusion. In a second cohort, regional cerebral blood flow (CBF) was measured ([(14)C]iodoantipyrine autoradiography) at end-occlusion in short-duration halothane (n=5) or short-duration propofol (n=5) anesthesia groups and in corresponding surgical shams (n=3 each). RESULTS: Pericranial temperature, PaO(2), PaCO(2), and blood pressure were controlled and not different among groups before or during occlusion. MCAO resulted in a similar immediate reduction in laser-Doppler flow signal after discontinuation of anesthesia in the awakening animals. Infarct volume was smaller in rats exposed to short-duration halothane in cortex (87.5+/-16.6 mm(3)) (mean+/-SEM) and caudoputamen (38.3+/-13.7 mm(3)) compared with rats exposed to short-duration propofol (cortex, 177.5+/-16.9 mm(3); caudoputamen, 47.8+/-2.9 mm(3)). Infarct volume was not different in long-duration halothane versus long-duration propofol treatment. Absolute cortical or caudoputamen intraischemic CBF was not different between short-duration halothane or short-duration propofol treatment. CONCLUSIONS: These data demonstrate that short-duration halothane exposure before MCAO in the awakening animal attenuates infarction volume compared with propofol. This protection by halothane is not mediated through preservation of intraischemic CBF. Longer durations of halothane exposure may activate secondary injury pathways, which negate the protective effects of short-term halothane preischemic treatment. (+info)
Recovery from propofol anaesthesia supplemented with remifentanil.
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We have examined the effects on recovery end-points of supplementation of a propofol-based anaesthetic with remifentanil. After induction of anaesthesia with propofol and remifentanil 1.0 microg kg(-1), 15 patients each were randomly allocated to target plasma propofol concentrations of 2, 3, 4 or 5 microg ml(-1) for maintenance of anaesthesia. Remifentanil was administered by infusion for supplementation in doses required for maintenance of adequate anaesthesia. All patients received 50% nitrous oxide in oxygen and ventilation was controlled. The total amount of drugs used and times to different recovery end-points were recorded. Cognitive function was also assessed using a Mini-Mental State questionnaire. The median dose of remifentanil for maintenance of adequate anaesthesia (excluding the initial bolus dose) in the four groups was 0.21, 0.15, 0.11 and 0.13 microg kg(-1) min(-1) respectively (P=0.0026). The median times to eye opening and orientation were shortest in the 2 microg ml(-1) group [6.0 and 6.5 min, 8.5 and 10.8 min, 13.4 and 15.8 min, and 14.2 and 19.5 min respectively in the propofol 2, 3, 4, and 5 microg ml(-1) groups respectively (P<0.001)]. The times to discharge from the recovery ward and the Mini-Mental State scores were not significantly different. (+info)
Recovery after remifentanil and sufentanil for analgesia and sedation of mechanically ventilated patients after trauma or major surgery.
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We investigated the analgesic effect and the neurological recovery time after administration of remifentanil in mechanically ventilated patients in an intensive care unit. Twenty patients, after trauma or major surgery with no intracranial pathology, were randomized to receive either remifentanil/propofol (n=10) or sufentanil/propofol (n=10). A sedation score and a simplified pain score were used to assess adequate sedation and analgesia. Medication was temporarily stopped after 24 h. Immediately before and 10 and 30 min after, the degree of sedation and pain score were evaluated. Adequate analgesia and sedation was achieved with remifentanil 10.6 microg kg(-1) h(-1) and propofol 2.1 mg kg(-1) h(-1), or sufentanil 0.5 microg kg(-1) h(-1) and propofol 1.3 mg kg(-1) h(-1). The difference in propofol dose between groups was significant. Ten minutes after terminating the medication, the degree of sedation decreased significantly after remifentanil and all patients could follow simple commands. During the following 20 min, all patients with remifentanil emerged from sedation and complained of considerable pain. By contrast, in the sufentanil group, only six (7) responded to commands after 10 (30) min and their pain score remained essentially unchanged during the 30-min observation period. We conclude that, in contrast to sufentanil, remifentanil facilitates rapid emergence from analgesia and sedation, allowing a clinical neurological examination within 10-30 min in mechanically ventilated patients with no intracranial pathology. (+info)
Infusion of amino acid enriched solution hastens recovery from neuromuscular block caused by vecuronium.
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We investigated the effect of an amino acid infusion on neuromuscular block produced by vecuronium, and on rectal temperature and surface temperature over the adductor pollicis muscle. Sixty adult patients undergoing general anaesthesia were randomly divided into four groups of 15 patients each: amino acid (AA)-post-tetanic count (PTC); AA-train-of-four (TOF); control (C)-PTC; or C-TOF group. In the AA-PTC and AA-TOF groups, after a bolus of vecuronium 0.1 mg kg(-1), a continuous infusion of an 18 amino acid enriched solution (AMIPAREN) was started at a rate of 166 kJ h(-1). In the C-PTC and C-TOF groups, normal saline was administered. Time from vecuronium to the return of the PTC in the AA-PTC group was significantly shorter than in the C-PTC group (mean (SD), 13.3 (4.5) versus 18.0 (5.6) min, P<0.05). Times to return of T1, T2, T3, and T4 (first, second, third, and fourth twitch of TOF) in the AA-TOF group were significantly shorter than in the C-TOF group (21.1 (4.5) versus 28.0 (8.2) min for T1, P<0.05). PTC in the AA-PTC group was significantly greater than in the C-PTC group; 25-35 min after administration of vecuronium (P<0.05). T1/T0 and T4/T1 in the AA-TOF group were significantly higher than in the C-TOF group, 40-120 and 50-120 min after vecuronium respectively (P<0.05). Rectal temperature and surface temperature over the adductor pollicis muscle in the AA-PTC and AA-TOF groups were significantly higher than in the control groups 50-120 and 100-120 min after vecuronium respectively (P<0.05). Infusion of amino acid enriched solution hastens recovery from neuromuscular block. (+info)
Xenon anaesthesia for laparoscopic cholecystectomy in a patient with Eisenmenger's syndrome.
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There are few reports on anaesthesia for patients with Eisenmenger's syndrome requiring non-cardiac surgery and none of the use of xenon. We describe the use of xenon with a closed-circuit system in a patient with Eisenmenger's syndrome having a laparoscopic cholecystectomy. (+info)
Small-dose selective spinal anaesthesia for short-duration outpatient gynaecological laparoscopy: recovery characteristics compared with propofol anaesthesia.
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A randomized controlled trial compared recovery characteristics after selective spinal anaesthesia (SSA) or propofol general anaesthesia (GA) for short-duration outpatient laparoscopic surgery. Forty women were randomized to receive either SSA (1% lidocaine 10 mg, sufentanil 10 microg and sterile water 1.8 ml) or GA (propofol and nitrous oxide 50% in oxygen). Compared with the GA group, times to leaving the operating room, performing a straight leg raise, performing deep knee-bends and achieving an Aldrete score >9 and the time in Phase II recovery were significantly shorter (P < 0.05) in the SSA group. (+info)
Analgesic efficacy of tramadol 2 mg kg(-1) for paediatric day-case adenoidectomy.
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We studied the analgesic efficacy of tramadol 2 mg kg(-1) for post-operative analgesia after day-case adenoidectomy in children aged 1-3 yr. Eighty children were allocated randomly to receive tramadol 2 mg kg(-1) i.v. or placebo immediately after induction of anaesthesia. Anaesthesia was induced with alfentanil 10 microg kg(-1) and propofol 4 mg kg(-1) followed by mivacurium 0.2 mg kg(-1) for tracheal intubation. Anaesthesia was continued with sevoflurane in nitrous oxide and oxygen. All children were given ibuprofen rectally at approximately 10 mg kg(-1) before the start of surgery. Post-operative pain and recovery assessments were performed by a nurse blinded to the analgesic treatment using the Aldrete recovery score, the pain/discomfort scale and measurement of recovery times. Rescue medication (pethidine in increments of 5 mg i.v.) was administered according to the pain scores. A post-operative questionnaire was used to evaluate the need for analgesia at home up to 24 h after operation. Rescue analgesic at home was rectal or oral ibuprofen 125 mg. Children in the tramadol group required fewer pethidine doses than those in the placebo group (P = 0.014). Forty-five per cent of children receiving tramadol did not require post-operative analgesia at all compared with 15% of children receiving placebo (P = 0.003). Recovery times and the incidence of adverse effects were similar in the two groups in the recovery room and at home. The requirement for rectal ibuprofen at home did not differ between groups. (+info)