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Acta Anaesthesiol Scand 2002 Oct;46(9):1137-43
Department of Anesthesiology and Intensive Care, Turku University Central Hospital, Finland. riikka.takala@tyks.fi
Previous studies have shown that both halothane and isoflurane have adverse but reversible effects on alveolar physiology. The present study was designed to test the hypothesis that also sevoflurane may affect alveolar integrity. Fifteen pigs were randomly selected to receive either thiopentone infusion (control group, n=8) or sevoflurane (n=7) at 4.0% inspiratory concentration (1.5 MAC) in air for 6 h. Tissue samples from the lungs were obtained at the end of the experiment. Both histopathological light microscopy and electron microscopy were used to assess the structural integrity of the alveoli. Pulmonary hemodynamics were comparable in both groups. Light microscopy showed no difference between the groups in the amount of alveolar macrophages, red blood cells or edema. Electron microscopy showed minor changes such as moderate local swelling of alveolar epithelium in both study groups. Alveolar type II cells were ultrastructurally unaltered in both study groups. We conclude that long-term, high concentration exposure to sevoflurane has no detrimental effect on the alveolar integrity in pigs.
PMID: 12366510, UI: 22252261
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Acta Anaesthesiol Scand 2002 Oct;46(9):1131-6
Department of Anesthesiology, Herlev Hospital, University of Copenhagen, Herlev, Denmark. pela@herlevhosp.kbhamt.dk
BACKGROUND: The orbicularis oculi (OO) muscle has been recommended for neuromuscular monitoring when the adductor pollicis (AP) muscle is not available. We investigated whether neuromuscular block could be measured reliably from the orbital part of the OO muscle by the use of acceleromyography. METHODS: During propofol, fentanyl, and alfentanil anaesthesia two TOF-Guards (Organon Teknika NV, Boxtel, the Netherlands) with acceleration transducers placed on the distal phalanx of the thumb and over the middle of the eyebrow, respectively, were used to measure neuromuscular block simultaneously in 23 patients during vecuronium-induced and neostigmine-antagonized neuromuscular block. For both muscles, the simultaneously recorded first response (T1) in the train-of-four (TOF) and TOF-ratio were measured both during onset and recovery of the block. Furthermore, both the AP muscle T1 and TOF-ratio responses were plotted against 10% intervals of the OO muscle responses during onset and recovery, respectively. RESULTS: The orbicularis oculi muscle had a shorter latency and a faster recovery to TOF-ratio 0.80 compared with the AP muscle. During onset and recovery, pronounced variations of the AP muscle T1 and TOF-ratio responses were observed when compared with the OO muscle. CONCLUSION: A significant clinical disagreement exists between the degree of paralysis measured at the OO and the AP muscles. It is impossible to obtain a reasonable estimate of the degree of block at the AP muscle when the block is measured from the OO muscle with acceleromyography. If used, there is substantial risk of overlooking a residual block, and adequate recovery of the block should be confirmed by a final AP muscle measurement.
PMID: 12366509, UI: 22252260
Anesthesiology 2002 Dec;97(6):1638-40
Department of Anesthesiology and Division of Intensive Care Medicine, University Hospital, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
PMID: 12459699, UI: 22346959
Anesthesiology 2002 Dec;97(6):1609-17
Department of Anesthesiology, Weiler Division, Montefiore Medical Center, 1825 Eastchester Road, Bronx, NY 10461, USA. BobLagasse@yahoo.com
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PMID: 12459692, UI: 22346952
Anesthesiology 2002 Dec;97(6):1582-90
Department of Anaesthesia, James Cook University Hospital, Middlesbrough, Cleveland TS4 3BW, UK. drdavidcooper@aol.com
BACKGROUND: In our routine practice, we observed a reduced incidence of fetal acidosis (umbilical artery pH < 7.20) at cesarean delivery during spinal anesthesia when a combination of phenylephrine and ephedrine was used as first line vasopressor therapy, compared with using ephedrine alone. METHODS: The study was randomized and double blind. It compared phenylephrine 100 microg/ml (phenylephrine group), ephedrine 3 mg/ml (ephedrine group), and phenylephrine 50 microg/ml combined with ephedrine 1.5 mg/ml (combination group), given by infusion, to maintain maternal systolic arterial pressure at baseline during spinal anesthesia for elective cesarean delivery. RESULTS: Fetal acidosis was less frequent in the phenylephrine group (1 of 48) (P = 0.004) and less frequent in the combination group (1 of 47) (P = 0.005) than in the ephedrine group (10 of 48). The mean systolic arterial pressure was similar for the three groups: Phenylephrine group median 98% (IQR 94-103) of baseline, ephedrine group 100% (96-106) and combination group 101% (97-108) (P = 0.11). The mean heart rate was higher in the ephedrine group (median 107% [IQR 99-118] of baseline) than in the phenylephrine group (88% [82-98]) (P < 0.0001), or the combination group (96% [86-102]) (P < 0.0001). Nausea and vomiting were less frequent in the phenylephrine group (nausea 17%, vomiting 0%) than in the ephedrine group (nausea 66%, vomiting 36%) (P < 0.0001), or the combination group (nausea 55%, vomiting 18%) (P < 0.0001). CONCLUSIONS: Giving phenylephrine alone by infusion at cesarean delivery was associated with a lower incidence of fetal acidosis and maternal nausea and vomiting than giving ephedrine alone. There was no advantage to combining phenylephrine and ephedrine because it increased nausea and vomiting, and it did not further improve fetal blood gas values, compared with giving phenylephrine alone.
PMID: 12459688, UI: 22346948
Anesthesiology 2002 Dec;97(6):1567-75
Department of Public Health and Epidemiology, University of Birmingham, Birmingham, UK. matt_ja_wilson@hotmail.com
BACKGROUND: The authors recently showed that "mobile" epidural analgesia, using low-dose local anesthetic-opioid mixtures, reduces the impact of epidural analgesia on instrumental vaginal delivery, relative to a traditional technique. The main prespecified assessment of pain relief efficacy, women's postpartum estimates of labor pain after epidural insertion, did not differ. The detailed analgesic efficacy and the anesthetic characteristics of the techniques are reported here. METHODS: A total of 1,054 nulliparous women were randomized, in labor, to receive boluses of 10 ml 0.25% bupivacaine (traditional), combined spinal-epidural (CSE) analgesia, or low-dose infusion (LDI), the latter groups utilizing 0.1% bupivacaine with 2 microg/ml fentanyl. Visual analog scale pain assessments were collected throughout labor and delivery and 24 h later. Details of the conduct of epidural analgesia, drug utilization, and requirement for anesthesiologist reattendance were recorded. RESULTS: A total of 353 women were randomized to receive traditional epidural analgesia, 351 received CSE, and 350 received LDI. CSE was associated with a more rapid onset of analgesia, lower median visual analog scale pain scores than traditional in the first hour after epidural insertion, and a significant reduction in bupivacaine dose given during labor. Pain scores reported by women receiving LDI were similar to those in the traditional group throughout labor and delivery. Anesthesiologist reattendance was low but greater with each mobile technique. CONCLUSIONS: Relative to traditional epidural analgesia, LDI is at least as effective and CSE provided better pain relief in the early stages after insertion. The proven efficacy of mobile epidurals and their beneficial impact on delivery mode make them the preferred techniques for epidural pain relief in labor.
PMID: 12459686, UI: 22346946
Anesthesiology 2002 Dec;97(6):1500-6
Department of Anaesthesiology, Weill Medical College of Cornell University, 525 East 68th Street, New York, NY 10021, USA.
BACKGROUND: General anesthetics inhibit evoked release of classic neurotransmitters. However, their actions on neuropeptide release in the central nervous system have not been well characterized. METHODS: The effects of representative intravenous and volatile anesthetics were studied on the release of sulfated cholecystokinin 8 (CCK8s), a representative excitatory neuropeptide, from isolated rat cerebrocortical nerve terminals (synaptosomes). Basal, elevated KCl depolarization-evoked and veratridine-evoked release of CCK8s from synaptosomes purified from rat cerebral cortex was evaluated at 35 degrees C in the absence or presence of extracellular Ca2+. CCK8s released into the incubation medium was determined by enzyme-linked immunoassay after filtration. RESULTS: Elevation of extracellular KCl concentration (to 15-30 mM) or veratridine (10-20 microm) stimulated Ca2+ -dependent CCK8s release. Basal, elevated KCl- or veratridine-evoked CCK8s release was not affected significantly by propofol (12.5-50 microm), pentobarbital (50 and 100 microm), thiopental (20 microm), etomidate (20 microm), ketamine (20 microm), isoflurane (0.6-0.8 mM), or halothane (0.6-0.8 mMm). CONCLUSIONS: Clinically relevant concentrations of several classes of general anesthetics did not affect basal, KCl-evoked, or veratridine-evoked CCK8s release from isolated rat cortical nerve terminals. This is in contrast to the demonstrable effects of certain general anesthetics on the release of amino acid and catecholamine transmitters. These transmitter-specific presynaptic effects of general anesthetics suggest that anesthetic-sensitive presynaptic targets are not common to all transmitter classes.
PMID: 12459677, UI: 22346937
Anesthesiology 2002 Dec;97(6):1466-76
Anesthesiology Department, Division of Gastroenterology and Hepatology, Mayo Clinic & Foundation, 200 Southwest First Street, Rochester, MN 55905, USA. johnson.michael@mayo.edu
BACKGROUND: To investigate the mechanism by which rare cases of spinal local anesthetic (LA) neurotoxicity occur, we have tested the hypotheses that LAs elevate cytoplasmic calcium (Ca2+(cyt)), that this is associated with a neurotoxic effect, and that lidocaine and bupivacaine differ in their neurotoxicity. METHODS: Neurons of the ND7 cell culture line, derived from dorsal root ganglion, were loaded with fura-2 and analyzed by digitized video fluorescence microscopy during 60 min LA exposure, allowing determination of Ca2+(cyt) and time of necrotic cell death (plasma membrane lysis) at the single neuron level. RESULTS: Lidocaine 0.1% and bupivacaine 0.025% caused minimal changes in Ca. Lidocaine 0.5-5% and bupivacaine 0.125-0.625% caused an early, small (less than threefold), concentration-dependent increase in Ca2+(cyt) that was transient and returned to near baseline within 10 min. Lidocaine 2.5% and 5% then caused a sustained, greater than ten-fold increase in Ca2+(cyt) and death in some neurons during the 60 min exposure period. Pretreatment with thapsigargin eliminated the initial transient increase in Ca2+(cyt), consistent with endoplasmic reticulum (ER) as its source, and increased neuronal death with 5% lidocaine, suggesting that lidocaine neurotoxicity can be increased by failure of ER to take up elevated Ca2+(cyt). The later sustained increase in Ca2+(cyt) seen with 2.5 and 5% lidocaine was prevented in Ca2+ -free medium, and restored when Ca2+ was added back to the buffer in the presence of lidocaine, suggesting that higher concentrations of lidocaine increase influx of Ca2+ through the plasma membrane. CONCLUSIONS: In this model, lidocaine greater than 2.5% elevates Ca2+(cyt) to toxic levels. Bupivacaine and lower concentrations of lidocaine transiently alter Ca2+(cyt) homeostasis for several minutes, but without an immediate neurotoxic effect within 60 min.
PMID: 12459673, UI: 22346933
Anesthesiology 2002 Dec;97(6):1451-7
Department of Anesthesiology, University of Virginia, Charlottesville, VA, USA.
BACKGROUND: Local anesthetics have been shown to selectively inhibit functioning of Xenopus laevis Gq proteins. It is not known whether a similar interaction exists with mammalian G proteins. The goal of this study was to determine whether mammalian Gq protein is inhibited by local anesthetics. METHODS: In Xenopus oocytes, the authors replaced endogenous Gq protein with mouse Gq (expressed in Sf9 cells using baculovirus vectors). Cells endogenously expressing lysophosphatidic acid or recombinantly expressing muscarinic m3 receptors were injected with phosphorothioate DNA antisense (or sense as control) oligonucleotides against Xenopus Gq. Forty-eight hours later, oocytes were injected with purified mouse Gq (5 x 10(-8) M) or solvent as control. Two hours later, the authors injected either lidocaine, its permanently charged analog QX314 (at IC50, 50 nl), or solvent (KCl 150 mM) as control and measured Ca-activated Cl currents in response to lysophosphatidic acid or methylcholine (one tenth of EC50). RESULTS: Injection of anti-Gq reduced the mean response size elicited by lysophosphatidic acid to 33 +/- 7% of the corresponding control response. In contrast, responses were unchanged (131 +/- 29% of control) in cells in addition injected with mouse Gq protein. Injection of mouse Gq protein "rescued" the inhibitory effect of intracellularly injected QX314: whereas QX314 was without effect on Gq-depleted oocytes, responses to lysophosphatidic acid after QX314 injection were inhibited to 44 +/- 10% of control response in cells in addition injected with mouse Gq protein (5 x 10(-8) M). Similar results were obtained for m3 signaling and intracellularly injected lidocaine. CONCLUSION: Inhibition of Gq function by local anesthetics is not restricted to Xenopus G proteins. Therefore, Gq should be considered as one additional intracellular target site for local anesthetics, especially relevant for those effects not explainable by sodium channel blockade (e.g., antiinflammatory effects).
PMID: 12459671, UI: 22346931
Anesthesiology 2002 Dec;97(6):1445-50
Klinik fur Anasthesiologie und Intensivmedizin, Universitat Essen, Hufelandstrasse 55, 45122 Essen, Germany. harald.groeben@uni-essen.de
BACKGROUND: Awake tracheal intubation may evoke reflex bronchoconstriction in asthmatics. Whether this effect is altered by the choice of the local anesthetic used or by pretreatment with a beta2-adrenoceptor agonist is unknown. Therefore, we assessed the effect of awake fiberoptic intubation after lidocaine or dyclonine inhalation with or without pretreatment with salbutamol on lung function in asthmatic volunteers. METHODS: Bronchial hyperreactivity was verified by an inhalational histamine challenge. On four different days in a randomized, double blind fashion the volunteers (n = 10) inhaled either dyclonine or lidocaine with or without salbutamol pretreatment. FEV1 was measured at baseline, following salbutamol or saline inhalation, after lidocaine or dyclonine inhalation, while intubated, and after extubation. Lidocaine and dyclonine plasma concentrations were also measured. Statistics: Two-way ANOVA, post hoc tests with Bonferroni correction, results are presented as mean +/- SD. RESULTS: Neither lidocaine nor dyclonine inhalation changed FEV1 significantly from baseline compared with placebo inhalation (4.43 +/- 0.67 l vs. 4.29 +/- 0.72 l, and 4.53 +/- 0.63 l vs. 4.24 +/- 0.80 l, respectively). Salbutamol slightly but significantly increased FEV1 (4.45 +/- 0.76 l vs. 4.71 +/- 0.61 l, P = 0.0034, and 4.48 +/- 0.62 l vs. 4.71 +/- 0.61 l, P = 0.0121, respectively). Following awake intubation FEV1 significantly decreased under lidocaine topical anesthesia (4.29 +/- 0.72 l to 2.86 +/- 0.87 l) but decreased even more under dyclonine anesthesia (4.24 +/- 0.80 l to 2.20 +/- 0.67 l; P < 0.0001). While salbutamol pretreatment significantly attenuated the response to intubation, it did not eliminate the difference between the effects of lidocaine and dyclonine. Only minutes after extubation FEV1 was similar compared with baseline. CONCLUSION: In asthmatics, awake fiberoptic intubation evokes a more than 50% decrease in FEV1 following dyclonine inhalation. Using lidocaine for topical anesthesia the decrease in FEV1 is significantly mitigated (35%) and can be even further attenuated by salbutamol pretreatment. Therefore, combined treatment with lidocaine and salbutamol can be recommended for awake intubation while the use of dyclonine, despite its excellent and longer lasting topical anesthesia, may be contraindicated in patients with bronchial hyperreactivity.
PMID: 12459670, UI: 22346930
Anesthesiology 2002 Dec;97(6):1434-44
Department of Anesthesiology, University of Washington, Seattle, WA, USA. hschwid@u.washington.edu
BACKGROUND: Anesthesia simulators can generate reproducible, standardized clinical scenarios for instruction and evaluation purposes. Valid and reliable simulated scenarios and grading systems must be developed to use simulation for evaluation of anesthesia residents. METHODS: After obtaining Human Subjects approval at each of the 10 participating institutions, 99 anesthesia residents consented to be videotaped during their management of four simulated scenarios on MedSim or METI mannequin-based anesthesia simulators. Using two different grading forms, two evaluators at each department independently reviewed the videotapes of the subjects from their institution to score the residents' performance. A third evaluator, at an outside institution, reviewed the videotape again. Statistical analysis was performed for construct- and criterion-related validity, internal consistency, interrater reliability, and intersimulator reliability. A single evaluator reviewed all videotapes a fourth time to determine the frequency of certain management errors. RESULTS: Even advanced anesthesia residents nearing completion of their training made numerous management errors; however, construct-related validity of mannequin-based simulator assessment was supported by an overall improvement in simulator scores from CB and CA-1 to CA-2 and CA-3 levels of training. Subjects rated the simulator scenarios as realistic (3.47 out of possible 4), further supporting construct-related validity. Criterion-related validity was supported by moderate correlation of simulator scores with departmental faculty evaluations (0.37-0.41, P < 0.01), ABA written in-training scores (0.44-0.49, < 0.01), and departmental mock oral board scores (0.44-0.47, P < 0.01). Reliability of the simulator assessment was demonstrated by very good internal consistency (alpha = 0.71-0.76) and excellent interrater reliability (correlation = 0.94-0.96; P < 0.01; kappa = 0.81-0.90). There was no significant difference in METI versus MedSim scores for residents in the same year of training. CONCLUSIONS: Numerous management errors were identified in this study of anesthesia residents from 10 institutions. Further attention to these problems may benefit residency training since advanced residents continued to make these errors. Evaluation of anesthesia residents using mannequin-based simulators shows promise, adding a new dimension to current assessment methods. Further improvements are necessary in the simulation scenarios and grading criteria before mannequin-based simulation is used for accreditation purposes.
PMID: 12459669, UI: 22346929
Anesthesiology 2002 Dec;97(6):1409-15
Department of Anesthesiology, Osaka Prefectural Habikino Hospital, 3-7-1 Habikino, Habikino City, Osaka, Japan 583-8588. hagihira@masui.med.osaka-u.ac.jp
BACKGROUND: The authors previously reported that, during isoflurane anesthesia, electroencephalographic bicoherence values changed in a fairly restricted region of frequency versus frequency space. The aim of the current study was to clarify the relation between electroencephalographic bicoherence and the isoflurane concentration. METHODS: Thirty elective abdominal surgery patients (male and female, aged 34-77 yr, American Society of Anesthesiologists physical status I-II) were enrolled. After electroencephalogram recording with patients in an awake state, anesthesia was induced with 3 mg/kg thiopental and maintained with oxygen and isoflurane. Continuous epidural anesthesia with 80-100 mg/kg 1% lidocaine was also administered. Using software they developed, the authors continuously recorded the FP1-A1 lead of the electroencephalographic signal and expired isoflurane concentration to an IBM-PC compatible computer. After confirming the steady state of each isoflurane (end-tidal concentration at 0.3, 0.5, 0.7, 0.9, 1.1, 1.3, and 1.5%), electroencephalographic bicoherence values were calculated. RESULTS: In a light anesthetic state, electroencephalographic bicoherence values were low (generally < or = 15.0%). At increased concentrations of isoflurane, two peaks of electroencephalographic bicoherence emerged along the diagonal line (f1=f2). The peak emerged at around 4.0 Hz and grew higher as isoflurane concentration increased until it reached a plateau (43.8 +/- 3.5%, mean +/- SD) at isoflurane 0.9%. The other peak, at about 10.0 Hz, also became significantly higher and reached a plateau (32.6 +/- 9.2%) at isoflurane 0.9%; at isoflurane 1.3%, however, this peak slightly decreased. CONCLUSION: Changes in the height of two electroencephalographic bicoherence peaks correlated well with isoflurane concentration.
PMID: 12459666, UI: 22346926
Anesthesiology 2002 Dec;97(6):1363-70
Department of Anaesthesia and Intensive Care, Royal Adelaide Hospital, Adelaide University, North Terrace, Adelaide, South Australia 5000, Australia. guy.ludbrook@adelaide.edu.au
BACKGROUND: The potential benefit of propofol dose regimens that use physiologic pharmacokinetic modeling to target the brain has been demonstrated in animals, but no data are available on the rate of propofol distribution to the brain in humans. This study measured the brain uptake of propofol in humans and the simultaneous effects on electroencephalography, cerebral blood flow velocity (V(mca)), and cerebral oxygen extraction. METHODS: Seven subjects had arterial and jugular bulb catheters placed before induction. Electroencephalography and V(mca) were recorded during induction with propofol while blood samples were taken from both catheters for later propofol analysis. Brain uptake of propofol was calculated using mass balance principles, with effect compartment modeling used to quantitate the rate of uptake. RESULTS: Bispectral index (electroencephalogram) values decreased to a minimum value of approximately 4 at around 7 min from the onset of propofol administration and then slowly recovered. This was accompanied by decreases in V(mca), reaching a minimum value of approximately 40% of baseline. Cerebral oxygen extraction did not change, suggesting parallel changes in cerebral metabolism. There was slow equilibrium of propofol between the blood and the brain (t(1/2keo) of 6.5 min), with a close relation between brain concentrations and bispectral index, although with considerable interpatient variability. The majority of the decreases in V(mca), and presumably cerebral metabolism, corresponded with bispectral index values reaching 40-50 and the onset of burst suppression. CONCLUSION: Description of brain distribution of propofol will allow development of physiologic pharmacokinetic models for propofol and evaluation of dose regimens that target the brain.
PMID: 12459660, UI: 22346920
Anesthesiology 2002 Dec;97(6):1335-7
PMID: 12459657, UI: 22346917
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Br J Anaesth 2002 Nov;89(5):800; discussion 800-1
PMID: 12393791, UI: 22280492
Br J Anaesth 2002 Nov;89(5):782-5
Whipps Cross Hospital, Whipps Cross Road, Leytonstone, London E11 1NR, UK.
We present the cases of three women who, within a 6-month period, suffered post-partum generalized tonic-clonic seizures. All had received an epidural in labour for analgesia and were subsequently diagnosed as suffering from postdural puncture headache. All were treated for that headache with Synacthen and one also received sumatriptan before her seizures. All made satisfactory recoveries and were discharged home. None displayed classical patterns suggestive of pre-eclampsia, meningitis, cortical venous thrombosis or any other pathological process that might explain these events adequately, and the specific precipitating factors were left unidentified.
PMID: 12393783, UI: 22280484
Br J Anaesth 2002 Nov;89(5):766-9
Department of Anaesthesia, Intensive Care and Pain Medicine, St Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
BACKGROUND: Residual paralysis following the use of neuromuscular blocking drugs remains a clinical problem. As part of departmental quality assurance, we examined the degree of postoperative residual curarization (PORC) following atracurium. METHODS: Forty patients undergoing general anaesthesia involving atracurium were studied. Quantitative neuromuscular monitoring (mechanomyography, Myograph 2000, Biometer, Denmark) was performed by assessing the response to supramaximal train-of-four (TOF) stimulation of the ulnar nerve. Anaesthesia was provided by non-participating clinicians who were blinded to the study data. A TOF ratio </=0.7 at extubation was classified as PORC. RESULTS: At antagonism of neuromuscular block, 70% (28/40) of patients had a TOF ratio </=0.7, and 65% (26/40) of patients had a TOF ratio </=0.7 at extubation. Peripheral nerve stimulator use was associated with a longer interval from antagonism of block to extubation (P=0.01), but was not associated with differences in atracurium dosage or a reduction in PORC at extubation. Patients with TOF ratio </=0.7 at extubation had surgery of shorter duration [59 (SEM 6) vs 103 (9) min, P<0.001], greater doses of atracurium relative to the duration of surgery [6 (1) vs 11 (1) micro g kg(-1) min(-1), P<0.005], and shorter intervals from administration of last dose of atracurium to antagonism of neuromuscular block [29 (2) vs 53 (9) min, P<0.005] and from antagonism to extubation [6 (1) vs 15 (4) min, P<0.01]. Duration of surgical procedure was the sole multivariate predictor of PORC [odds ratio 0.94 (95% confidence intervals 0.91-0.98), P<0.01]. CONCLUSIONS: PORC remains a clinical problem despite use of intermediate-duration neuromuscular blocking drugs and peripheral nerve stimulators. Patients undergoing procedures of short duration may be at risk of inappropriately early tracheal extubation, possibly due to work pressures. The association between suboptimal antagonism of neuromuscular blockade and short procedures needs reinforcement during postgraduate training and departmental quality assurance.
PMID: 12393778, UI: 22280479
Br J Anaesth 2002 Nov;89(5):729-32
Department of Anaesthesiology, Kansai Medical University, 10-15 Fumizono-cho, Moriguchi City, Osaka 570-8507, Japan.
BACKGROUND: We have compared the laryngeal tube and laryngeal mask in 22 patients for the success rate of insertion, gas leak pressure and the incidence of gastric insufflation. METHOD: In a randomized, crossover design, the laryngeal tube and laryngeal mask were inserted in turn after induction of anaesthesia and neuromuscular block. The cuffs were inflated until the intracuff pressure reached 60 cm H(2)O. We measured adequacy of ventilation and the minimum airway pressure at which gas leaked around the cuff. The presence or absence of gastric insufflation was studied at an inflation pressure of 20 cm H(2)O. RESULTS: It was possible to ventilate through the laryngeal tube in 21 patients and through the laryngeal mask in 21 patients. The mean leak pressure for the laryngeal tube (26 (SD 5) cm H(2)O) was significantly greater than that for the laryngeal mask (19 (4) cm H(2)O) (P<0.01; 95% confidence intervals for mean difference: 5.3-10.2 cm H(2)O). Gastric insufflation did not occur when the laryngeal tube was used and was noted in three patients when the laryngeal mask was used. CONCLUSION: The laryngeal tube provides a better seal in the oropharynx than the laryngeal mask.
PMID: 12393771, UI: 22280472
Br J Anaesth 2002 Nov;89(5):722-8
Department of Anesthesiology and Intensive Care Medicine, Klinikum der Stadt Ludwigshafen, Bremserstrasse 79, D-67063 Ludwigshafen, Germany.
BACKGROUND: Hydroxyethyl starch (HES) may affect blood coagulation. We studied the effects of a modified, balanced, high-molecular weight [mean molecular weight (MW) 550 kDa], high-substituted [degree of substitution (DS) 0.7] HES preparation (Hextend) on coagulation in patients undergoing major abdominal surgery. METHODS: Patients were allocated randomly to receive Hextend) (n=21), lactated Ringer's solution (RL, n=21) or 6% HES with a low MW (130 kDa) and a low DS (0.4) (n=21). The infusion was started after induction of anaesthesia and continued until the second postoperative day to maintain central venous pressure between 8 and 12 mm Hg. Activated thrombelastography (TEG) was used to assess coagulation. Different activators were used (extrinsic and intrinsic activation of TEG) and aprotinin was added to assess hyperfibrinolytic activity (ApTEG). We measured onset of coagulation [coagulation time (CT=reaction time, r)], the kinetics of clot formation [clot formation time (CFT=coagulation time, k)] and maximum clot firmness (MCF=maximal amplitude, MA). Measurements were performed after induction of anaesthesia, at the end of surgery, 5 h after surgery and on the mornings of the first and second days after surgery. RESULTS: Significantly more HES 130/0.4 [2590 (SD 260) ml] than Hextend) [1970 (310) ml] was given. Blood loss was greatest in the Hextend) group and did not differ between RL- and HES 130/0.4-treated patients. Baseline TEG data were similar and within the normal range. CT and CFT were greater in the Hextend) group immediately after surgery, 5 h after surgery and on the first day than in the two other groups. ApTEG MCF also changed significantly in the Hextend) patients, indicating more pronounced fibrinolysis. Volume replacement using RL caused moderate hypercoagulability, shown by a decrease in CT. CONCLUSION: A modified, balanced high-molecular weight HES with a high degree of substitution (Hextend) adversely affected measures of coagulation in patients undergoing major abdominal surgery, whereas a preparation with a low MW and low DS affected these measures of haemostasis less. Large amounts of RL decreased the coagulation time.
PMID: 12393770, UI: 22280471
Br J Anaesth 2002 Nov;89(5):697-701
Department of Anaesthesiology and Critical Care, Centre Hospitalier Universitaire Pitie-Salpetriere, Assistance Publique-Hopitaux de Paris (AP-HP), Universite Pierre et Marie Curie, Paris, France.
BACKGROUND: Postoperative morphine titration frequently induces sedation. The assumption is made that patients sleep when their pain is relieved. Some patients complain of persistent pain when they awake. We studied the time-course of sedation and analgesia to understand the determinants of patients' sleep during morphine titration. METHODS: Seventy-three patients requiring morphine titration in a post-anaesthetic care unit after major surgery, were studied. Fifty-two patients slept (Sleep group) and 21 did not (Awake group). When a patient slept during titration, morphine was discontinued. Visual analogue pain scale (VAS), Ramsay score (RS), and the bispectral index (BIS) were recorded at the beginning of titration (STonset), at sleep onset (STsleep), then 5, 10, 20, and 30 min afterwards (ST4). RESULTS: In the Sleep group, mean (SD) RS increased from 1.7 (0.4) to 2.4 (0.6) (P<0.05 vs STonset) and BIS decreased from 95 (5.0) to 89.8 (10.2) between STonset and STsleep (P<0.05), RS remained stable thereafter. Conversely, RS and BIS remained unaltered in the Awake group. The reduction in VAS was comparable between groups (from 78 (17) to 39 (21), and from 64 (16) to 30.4 (11), respectively). Even though mean (SD) VAS was 39 (21) at ST4 in the Sleep group, 13 patients (25%) maintained a VAS above 50 mm. CONCLUSION: We observed dissociated effects of morphine on the time-course of sedation and analgesia with sedation occurring first, followed by analgesia. Therefore, morphine-induced sedation should not be considered as an indicator of an appropriate correct level of analgesia during i.v. morphine titration.
PMID: 12393765, UI: 22280466
Eur J Anaesthesiol 2002 Oct;19(10):768-70
[Medline record in process]
PMID: 12463393, UI: 22350797
Eur J Anaesthesiol 2002 Oct;19(10):762; author reply 763
PMID: 12463390, UI: 22350794
Eur J Anaesthesiol 2002 Oct;19(10):755-9
Clinique Generale St Jean, Service d'anesthesie, Bruxelles, Belgium. JEAN-LUC.DEMEERE@village.uunet.be
BACKGROUND AND OBJECTIVE: The study evaluated the manpower requirements in anaesthesia in Belgium until 2020. The basic intent was to estimate the need for anaesthesiologists in different hospitals because the number of medical students will be reduced to 700 in 2004 and to 600 in 2007 (numerus clausus), and the number of trainees in anaesthesia from 110 to 42 (best scenario) or to 21 (worst scenario). Simultaneous anaesthesia (more than one patient at the same time) is not allowed by our professional safety rules or by the Belgian Ministry of Public Health. The questions are: will we have enough anaesthesiologists in the next 20 years, and is there a need for nurses to administer anaesthesia? This professional title of nurse anaesthetist does not presently exist in Belgium. METHODS: Every registered anaesthesiologist in Belgium received a questionnaire about the manpower requirements in his or her institution expected over the next 20 years. The workload in the specialty was also considered. RESULTS: We received 154 replies from 186 different hospitals. The workload is definitely high: 10 h per day was devoted to clinical work and 4.6 h per week to administration. Belgium will need 51 anaesthesiologists each year after 2004, and 58 each year from 2010 to 2020. CONCLUSIONS: Will anaesthesiologists accept their present high workload for the next 20 years? If not, the consequences will be serious. Three-quarters (75.4%) of the replies identified a need for more anaesthesiologists and considered that an anaesthesiologist supervising anaesthesia nurses for a number of patients simultaneously was a possible solution.
PMID: 12463388, UI: 22350792
Eur J Anaesthesiol 2002 Oct;19(10):749-54
Toolo Hospital, Helsinki University Central Hospital, Department of Anaesthesia, Helsinki, Finland. paivi.tanskanen@hus.fi
BACKGROUND AND OBJECTIVE: Thiopental prolongs the QT interval more than propofol, and the two induction agents were compared in patients with subarachnoid haemorrhage predisposed to electrocardiographic abnormalities and cardiac dysrhythmias. METHODS: Twenty-nine patients were studied randomly. Anaesthesia was induced with either thiopental or propofol and fentanyl; vecuronium was used as a neuromuscular blocking agent. The electrocardiogram and arterial blood pressure were monitored from before the induction of anaesthesia to 2 min after endotracheal intubation. RESULTS: The median QT interval was at baseline 423 ms in the thiopental group and at 432 ms in the propofol group, and it increased in the thiopental group to 446 ms and decreased in the propofol group to 425 ms (P < 0.01 between groups). After induction and endotracheal intubation, the number of patients with increased QT dispersion was greater in the propofol group (P < 0.05). The incidence of cardiac dysrhythmias was similar in the study groups. CONCLUSIONS: Thiopental and propofol are equally suitable for the induction of anaesthesia in patients with subarachnoid haemorrhage.
PMID: 12463387, UI: 22350791
Eur J Anaesthesiol 2002 Oct;19(10):742-8
Catharina Hospital, Department of Surgery, Eindhoven, The Netherlands.
BACKGROUND AND OBJECTIVE: Multimodality treatment for patients with locally advanced primary or locally recurrent rectal cancer, including high-dose preoperative external beam radiotherapy, extensive surgery and intraoperative radiation therapy, decreases the local recurrence rates and improves survival. During this aggressive operation, the anaesthesiologist is faced with potential problems such as major transfusion requirements, hypothermia, intraoperative position changes, the need to transport the patient to the intraoperative radiation therapy applicator, and the risks associated with remote monitoring of the patient during the 10 min intraoperative radiation therapy application. The anaesthetic management and perioperative results were evaluated for the anaesthetic results and the complications. METHODS: One-hundred-and-six patients undergoing the multimodality treatment between February 1994 and March 2000 for locally advanced primary (n = 50) and locally recurrent rectal cancer (n = 56) were retrospectively evaluated for their anaesthetic results and complications. RESULTS: All patients were operated upon using a combination of general and epidural anaesthesia. The average duration of anaesthesia was 6 (range 3-10.5) h and the mean blood loss 3.6 (range 0.4-14) L. All patients recovered well from anaesthesia. Two patients (2%) died in the intensive care unit (34 and 48 days postoperatively) because of adult respiratory distress syndrome following postoperative haemorrhage. Severe haemorrhage during or after the operation was significantly related with the development of adult respiratory distress syndrome (P < 0.0001). CONCLUSION: With adequate preoperative assessment and optimalization of the patient's condition, maintaining peroperative haemodynamic stability with the help of adequate remote monitoring, early and fast transfusion, and multidisciplinary communication, anaesthetic complications can be minimized.
PMID: 12463386, UI: 22350790
Eur J Anaesthesiol 2002 Oct;19(10):735-41
University of Bonn, Department of Anaesthesiology and Intensive Care Medicine, Bonn, Germany. jbruhn@mailer.meb.uni-bonn.de
BACKGROUND AND OBJECTIVE: The common parameters of the electroencephalogram quantify a shift of its power spectrum towards lower frequencies with increasing anaesthetic drug concentrations (e.g. spectral-edge frequency 95). These ad hoc parameters are not optimized for the content of information with regard to drug effect. Using semilinear canonical correlation, different frequency ranges (bins) of the power spectrum can be weighted for sensitivity to changes of drug concentration by multiplying their power with iteratively determined coefficients, yielding a new (canonical univariate) electroencephalographic parameter. METHODS: Electroencephalographic data obtained during application of volatile anaesthetics were used: isoflurane (n = 6), desflurane (7), sevoflurane (7), desflurane during surgical stimulation (12). Volatile anaesthetic end-tidal concentrations varied between 0.5 and 1.6 minimum alveolar concentration (MAC). The canonical univariate parameter and spectral-edge frequency 95 were determined and their correlation with the volatile anaesthetic effect compartment concentration, obtained by simultaneous pharmacokinetic-pharmacodynamic modelling, were compared. RESULTS: The canonical univariate parameter with individually optimized coefficients, but not with mean coefficients, was superior to the spectral-edge frequency 95 as a measure of anaesthetic drug effect. No significant differences of the coefficients were found between the three volatile anaesthetics or between the data with or without surgical stimulus. The coefficients for volatile anaesthetics were similar to the coefficients for opioids, but different from coefficients for propofol and midazolam. CONCLUSIONS: The canonical univariate parameter calculated with individually optimized coefficients, but not with mean coefficients, correlates more accurately and consistently with the effect site concentrations of volatile anaesthetics than with spectral-edge frequency 95.
PMID: 12463385, UI: 22350789
Eur J Anaesthesiol 2002 Oct;19(10):727-34
Ghent University Hospital, Department of Anaesthesia, Ghent, Belgium. michel.struys@rug.ac.be
BACKGROUND AND OBJECTIVE: The study was designed to compare the costs of propofol versus sevoflurane for the maintenance of the hypnotic component of anaesthesia during general anaesthesia, guided by the bispectral index, for gynaecological laparoscopic surgery. METHODS: Forty ASA Grade I-II female patients scheduled for gynaecological laparoscopy were randomly allocated to two groups. All patients received a continuous infusion of remifentanil (0.25 microg kg(-1) min(-1)) for 2 min. Then anaesthesia was induced with propofol 1% at 300 mL h(-1) until loss of consciousness. To guide the bispectral index between 40 and 60, Group 1 patients received propofol 10 mg kg(-1) h(-1) initially, which was increased or decreased by 2 mg kg(-1) h(-1) steps; Group 2 patients received sevoflurane, initially set at 2 vol.% and adjusted with steps of 0.2-0.4%. The time and quality of anaesthesia and recovery were assessed in two postoperative standardized interviews. RESULTS: Patient characteristics, the propofol induction dose, the bispectral index and the haemodynamic profiles during induction of anaesthesia, and its duration, were similar between the groups. In Group 1, 7.55 +/- 1.75 mg kg(-1) h(-1) propofol and in Group 2, 0.20 +/- 0.09 mL kg(-1) h(-1) liquid sevoflurane were used for maintenance. The cost for maintenance, including wasted drugs, was higher when using propofol (Euro 25.14 +/- 10.69) than sevoflurane (Euro 12.80 +/- 2.67). Postoperatively, recovery profiles tended to be better with propofol; however, the day after discharge no differences were found. CONCLUSIONS: When applying the bispectral index to guide the administration of hypnotic anaesthetic drugs, propofol-based maintenance of anaesthesia was associated with the highest cost. A trend towards a better recovery profile was obtained with propofol. However, on the day after discharge, no differences in quality were observed.
PMID: 12463384, UI: 22350788
Eur J Anaesthesiol 2002 Oct;19(10):717-26
Imperial College School of Technology and Medicine, Northwick Park Hospital, Division of Anaesthesia, Surgery and Intensive Care, Harrow, UK. c.thornton@ic.ac.uk
BACKGROUND AND OBJECTIVE: Parallels exist between the coma associated with cerebral malaria and general anaesthesia. They both produce reversible loss of consciousness. In the case of cerebral malaria and in the absence of other complications, patients recover without sequelae. General anaesthetics are so designed that patients recover from their anaesthetics very quickly and show no 'after effects'. This study compares brain function in these two clinical conditions by examining auditory- (AEPs) and median nerve somatosensory-evoked potentials (SEPs). The AEPs studied (waves Pa and Nb) are thought to arise from the primary auditory cortex and the median nerve SEPs (waves P15, N20, P25, N35, P45) from the pons, thalamus and primary somatosensory cortices. METHODS: Six comatosed patients with malaria (three males, three females) aged between 19 and 38 yr were studied in Zimbabwe. Their Glasgow Coma Scores on admission were 4, 3, 6, 7, 7 and 11. Their AEPs and median nerve SEPs were recorded daily over 4 days. The data were compared with those previously collected in the UK on patients and volunteers anaesthetized with desflurane, isoflurane, sevoflurane and propofol. RESULTS: In general, patients with cerebral malaria showed AEPs and SEPs similar to those of light to moderate anaesthesia i.e. 0.5-1.25 measure of anaesthetic potency (MAC), where 1 MAC is the minimum alveolar concentration necessary to prevent movement to surgical incision in 50% of patients. The appearance of the AEPs and SEPs bore no relationship to the degree of coma. The auditory brainstem-evoked response was retained in all degrees of coma, as would be expected. Otherwise, it would not be possible to interpret the waveform. In most instances, the early cortical complex Pa/Nb/Pb of the AER was present. When comatose patients emerged from malarial coma or were stimulated by talking loudly to them, they showed changes in the Pa/Nb/Pb complex similar to those seen on awakening from anaesthesia. The somatosensory-evoked response showed clear P15, N20 and P25 peaks at the expected latencies, and in some instances the waveforms of cerebral malaria and lightly anaesthetized volunteers were very similar. CONCLUSIONS: The sensory-evoked responses of the cerebral malaria patients recorded in this study were not markedly different from those seen in light-to-moderately anaesthetized patients and volunteers. The profound depression of the AEPs and SEPs associated with deeper levels of anaesthesia were not seen, with the exception of one patient several hours before death.
PMID: 12463383, UI: 22350787
Eur J Pharmacol 2002 Dec 20;457(2-3):161-168
Departamento de Fisiologi;a, Facultad de Medicina, Universidad Autonoma, Arzobispo Morcillo, 2, 28029, Madrid, Spain
[Record supplied by publisher]
To examine the coronary reactivity to endothelin-1 and its interaction with nitric oxide or prostanoids during partial coronary ischemia and reperfusion, left circumflex coronary artery flow was electromagnetically measured, and partial occlusion of this artery was induced for 60 min, followed by reperfusion in anesthetized goats (eight non-treated, six treated with N(w)-nitro-L-arginine methyl esther (L-NAME) and five treated with meclofenamate). During partial occlusion, coronary vascular conductance was reduced by 24-37% (P<0.01), and the coronary vasodilatation in response to acetylcholine (3-100 ng) and sodium nitroprusside (1-10 &mgr;g) was much decreased in every case; the vasoconstriction in response to endothelin-1 (1-10 &mgr;g) was depressed in non-treated animals, and this depression was reversed by L-NAME and was accentuated by meclofenamate. At 30 min of reperfusion coronary vascular conductance remained decreased by 22-27% (P<0.01), and the vasodilatation in response to acetylcholine (3-100 ng) and sodium nitroprusside (1-10 &mgr;g), as well as the vasoconstriction with endothelin-1 (1-10 &mgr;g), were as in the control and comparable in the three groups of animals. These results suggest: (a) that during ischemia, the coronary vasodilator reserve is greatly reduced, and the vasoconstriction with endothelin-1 is blunted, with preservation of the modulatory role of nitric oxide and involvement of vasoconstrictor prostanoids in this vasoconstriction, and (2) that during reperfusion, the coronary vasodilator reserve and the coronary reactivity to acetylcholine and endothelin-1 recover, but the modulatory role of nitric oxide in this reactivity may be attenuated.
PMID: 12464362
J Oral Maxillofac Surg 2002 Dec;60(12):1503-5
Oral and Maxillofacial Surgery, Hospital of St Raphael, New Haven, CT 06511, USA.
PMID: 12465019, UI: 22352337
J Oral Maxillofac Surg 2002 Nov;60(11):1246-9
Department of Anesthesiology, University of Tsukuba Institute of Clinical Medicine, Tsukuba City, Ibaraki, Japan. yfujii@igaku.md.tsukuba.ac.jp
PURPOSE: The study goal was to evaluate the efficacy and safety of a small dose of propofol for the prevention of nausea and vomiting following third molar extraction. PATIENTS AND METHODS: In a prospective, randomized, double-blinded, placebo-controlled trial, 90 women received placebo or propofol at 2 different doses (0.25 mg/kg, 0.5 mg/kg) (n = 30 of each) intravenously at the end of surgery. A standard general anesthetic technique, including sevoflurane and nitrous oxide in oxygen, was employed throughout the surgical procedure. Emetic episodes and safety assessments were performed during 0 to 3 hours and 3 to 24 hours after after anesthesia. RESULTS: The rate of patients experiencing emesis-free (no nausea, retching, or vomiting) during 0 to 3 hours after anesthesia was 60% with placebo, 66% with propofol 0.25 mg/kg (P =.395), and 90% with propofol 0.5 mg/kg (P =.001); the corresponding rate during 3 to 24 hours after anesthesia was 60%, 63% (P = 0.5), and 87% (P =.02) (P values compared with placebo). No clinically serious adverse effects due to the study drug were observed in any group. CONCLUSIONS: Prophylactic therapy with a small dose (0.5 mg/kg) of propofol is effective for preventing postoperative nausea and vomiting in female patients undergoing general anesthesia for third molar extractions. Copyright 2002 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 60:1246-1249, 2002
PMID: 12420256, UI: 22307471
Lancet 2002 Oct 26;360(9342):1322
Sunnybrook and Women's College Health Sciences Centre, University of Toronto, Ontario, M5G 1N8, Toronto, Canada.
PMID: 12414224, UI: 22302435