Ultimo Aggiornamento: 31 Dicembre 2002

Acta Anaesthesiol Scand 2001 Nov;45(10):1276-80

Plasma concentrations of ropivacaine following a single-shot caudal block of 1, 2 or 3 mg/kg in children.

Bosenberg AT, Thomas J, Lopez T, Huledal G, Jeppsson L, Larsson LE

Department of Anaesthesia, Faculty of Medicine, University of Natal, Durban, South Africa. bosie@nu.ac.za

BACKGROUND: For documenting the properties of ropivacaine used for regional anaesthesia in children, the relationship between dose and resulting systemic exposure is essential. The aim of this pharmacokinetic part of a randomised, multicentre, double-blind study was to determine the free and total plasma levels of ropivacaine in children aged between 4 and 12 years following a single-shot caudal dose of 1, 2 or 3 mg/kg of ropivacaine for postoperative pain management. METHOD: Following induction of a standardised general anaesthetic (halothane; nitrous oxide: oxygen 60:40), a caudal block using 1 ml/kg ropivacaine in concentrations of 1, 2 or 3 mg/ml was performed in 43 ASA I children (body weight 12-25 kg) scheduled for elective inguinal surgery. Blood samples were collected prior to and 15, 30, 45, 60 and 240 min after placement of the caudal block for determination of total and free ropivacaine plasma concentrations. RESULTS: The peak plasma concentration of total ropivacaine, reached within 15-241 min after the block, increased in proportion to dose, with mean values at 0.27, 0.64 and 0.90 mg/l following 1, 2 and 3 mg/kg respectively. The peak plasma level of free ropivacaine also increased in a dose-proportional manner, with mean levels at 0.014, 0.030 and 0.042 mg/l. The highest individual peak plasma level of free ropivacaine was 0.070 mg/l, well below the threshold levels of CNS toxicity described in adults. No clinical signs of systemic toxicity were observed. CONCLUSION: Following single-shot caudal doses of 1-3 mg/kg in children up to 25 kg and aged between 4 and 12 years, plasma levels of free ropivacaine increase in proportion to dose and all were shown to be within safe limits.

Publication Types:

• Clinical trial
• Multicenter study
• Randomized controlled trial

PMID: 11736682, UI: 21598725

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Acta Anaesthesiol Scand 2001 Nov;45(10):1235-40

Effects of sustained pressure application on compliance and blood gases in healthy porcine lungs.

Markstrom A, Hedlund A, Sjostrand U, Nordgren A, Lichtwarck-Aschoff M

Department of Surgical Sciences/Section of Anaesthesiology and Intensive Care, University Hospital, Uppsala, Sweden. agneta.markstrom@ane.ds.sll.se

BACKGROUND: Short periods of sustained increase in airway pressures (Press(up)) are believed to re-open lung areas that collapsed upon induction of anaesthesia. Recruitment of alveolar surface is usually assessed in terms of changes in the pressure-volume (PV) curve. The purpose of this study was to analyse PV-curves before and after a Press(up) and to ascertain whether such changes are compatible with the concept of recruitment of lung volume. METHODS: During ketamine anaesthesia, 12 healthy piglets were subjected to a Press(up) with end-expiratory pressure (PEEP) of 12 cmH2O and end-inspiratory pressure of 40 cmH2O. Before and after Press(up), PV-curves were obtained from a slow insufflation of 630 ml at zero PEEP (ZEEP). RESULTS: Compliance was non-linear both before and after Press(up) increasing up to 300 ml and sharply decreasing thereafter. After Press(up), the entire compliance curve was shifted to a higher absolute level. Up to 100 ml and a pressure level corresponding to the lower inflection point on the PV-curve (LIP), compliance was higher before Press(up). No effects on blood gases could be observed. CONCLUSION: If the similar shape of the compliance curve corresponds to a similar chain of re-opening and overdistension events, this would imply that all volume gained by Press(up) is lost within 10 min, without explaining the higher absolute compliance following Press(up). We speculate that a) re-opening of rapidly collapsing small airways determines the initial compliance increase; b) the lower compliance after Press(up) until LIP indicates reduced intratidal re-opening of lung regions; and c) changes in bronchomotor tone induced by Press(up) raise the absolute compliance, with a similar scenario of alveolar and small airway recruitment now taking place but at different degrees of airway stiffness.

PMID: 11736676, UI: 21598719

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Acta Anaesthesiol Scand 2001 Nov;45(10):1210-4

Practice and knowledge of cricoid pressure in southern Sweden.

Schmidt A, Akeson J

Department of Anaesthesia and Intensive Care, Helsingborg Hospital, Helsingborg, Sweden. anders.schmidt@helsingborgslasarett.se

BACKGROUND: For 40 years cricoid pressure has been used to prevent regurgitation of gastric contents during induction of anaesthesia. Recent studies have emphasised use of more moderate force so as not to deteriorate ventilation or endotracheal intubation. This study was undertaken to assess the current practice and knowledge of cricoid pressure among anaesthesia personnel in southern Sweden. METHODS: Forty-eight subjects at two anaesthetic departments in southern Sweden were asked to apply and maintain cricoid pressure for 60 s with their dominant and non-dominant hands, respectively, in a laryngotracheal model during simulated intravenous induction of anaesthesia. Where and how pressure was applied as well as the force used by each subject was recorded together with information on individual experience and knowledge of the technique. RESULTS: There were no significant changes in force applied over time, and no significant differences in force between dominant (median 36 N; 25th percentile 26 N; 75th percentile 50 N) and non-dominant (37; 26; 50 N) hand, between female and male subjects or between physicians, nurses and assistant nurses. Force exceeding 60 N was recorded at least once in 21% of subjects. More than two-thirds (69%) had not heard of any recommended level of force to be applied. Forty percent of anaesthesiologists were unaware of any contraindications. CONCLUSION: More specific education and training seems mandatory to improve clinical use of cricoid pressure and possibly increase patient safety. Simulators allowing cricoid pressure to be carried out and evaluated in a standardised manner should therefore be incorporated into future training programmes and airway management courses.

PMID: 11736671, UI: 21598714

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Acta Anaesthesiol Scand 2001 Nov;45(10):1196-203

Rocuronium and anaphylaxis--a statistical challenge.

Laake JH, Rottingen JA

Department of Anaesthesiology, National Hospital (Rikshospitalet), Oslo, Norway. j.h.laake@basalmed.uio.no

Drug induced anaphylaxis is frequently attributed to the use of muscle relaxants during anaesthesia. Recently The Norwegian Medicines Agency recommended that rocuronium bromide (Esmeron) be withdrawn from routine practice due to frequent reports of anaphylaxis. Over a period of two and a half years approximately 150,000 patients received rocuronium as part of their anaesthesia. In this period the Norwegian drug authorities received 29 reports of anaphylaxis or anaphylactoid reactions in patients treated with rocuronium. This is in stark contrast to the situation in other Nordic countries where a total of only seven cases of anaphylaxis in approximately 800,000 patients treated with rocuronium had been recorded by December 2000. This situation highlights the many potential problems of the surveillance of adverse drug reactions: reporting bias may lead to an over-estimate of the risk of one drug compared to another, and the possibility of under-reporting of adverse events (due to a weak reporting culture) further limit the validity of such comparisons. The surveillance of adverse drug reactions also represents a statistical challenge. While adverse event reports may help us to estimate the anaphylaxis rate we need to appreciate the uncertainty of such estimates. Adverse reactions are rare, random, and mostly independent events, resulting from the successive exposure of patients to a low risk intervention. The frequency distribution of adverse events will therefore conform to that of a Poisson process. The resulting Poisson distribution may inform us about the variability of adverse event data. An understanding of these methodological problems and statistical challenges will allow anaesthesiologists to make informed decisions concerning the use of muscle relaxants and other drugs associated with severe adverse reactions.

PMID: 11736669, UI: 21598712

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Anaesthesist 2001 Nov;50(11):842-5

[Less pain on injection by a new formulation of propofol? A comparison with propofol LCT].

Larsen B, Beerhalter U, Biedler A, Brandt A, Doege F, Brun K, Erdkonig R, Larsen R

Klinik fur Anaesthesiologie und Intensivmedizin, Universitatskliniken des Saarlandes, Kirrberger Strasse, 66421 Homburg/Saar. airlar@uniklinik-saarland.de

BACKGROUND: Pain on injection is a major disadvantage of propofol, experienced by the vast majority of patients. Since the traditional formulation has almost normal osmolality and pH, it is hypothesised that the concentration of free propofol in the aqueous phase of the emulsion is responsible for the pain and that reducing the amount of free propofol would also reduce the frequency and intensity of pain on injection. This study was designed to investigate whether pain on injection can be reduced in frequency and intensity by a new formulation of propofol. METHODS: We performed a monocentre, controlled, randomised, double-blind study to compare the pain produced by intravenous injection of a new propofol preparation (propofol-MCT/LCT) with standard propofol in patients undergoing elective surgical procedures. A total of 184 non-premedicated patients received either 1% propofol prepared in a mixture of medium and long chain triglycerides (Propofol-MCT/LCT, Propofol- Lipuro, B. Braum Melsungen AG) or standard 1% propofol prepared exclusively in long chain triglycerides (Propofol-LCT; Disoprivan, AstraZeneca) into a vein of the dorsal hand for induction of anaesthesia. Anaesthesia was maintained by TIVA with propofol and remifentanil. Pain on injection was recorded and graded as none, mild, moderate or severe. RESULTS: Patients receiving propofol-MCT/LCT had a significantly lower incidence of pain on injection compared to the standard propofol group (37% vs 64%) with the intensity of pain also being less severe. There were no differences between both groups in propofol dosage for induction (3.2 +/- 0.8 mg/kg vs 3.3 +/- 0.9 mg/kg) and maintenance of anaesthesia (3.4 +/- 0.6 mg/kg/h vs 3.2 +/- 0.5 mg/kg/h), remifentanil dosage (25 +/- 6 micrograms/kg/h vs. 24 +/- 6 micrograms/kg/h), intraoperative hemodynamics, recovery parameters and postoperative patient satisfaction. Postoperative thrombophlebitis at the injection site for propofol was not observed in any of the patients. CONCLUSIONS: Propofol-MCT/LCT produced significantly less pain on injection when compared to standard propofol in ASA I and II patients undergoing elective surgery. Pain was also significantly less severe, with both effects presumably being due to the lower concentration of free propofol in the MCT/LCT-preparation. With regard to injection pain propofol-MCT/LCT offers significant a advantage over standard propofol.

Publication Types:

• Clinical trial
• Randomized controlled trial

PMID: 11760478, UI: 21597280

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Anesthesiology 2001 Dec;95(6):1537-9

What are "relevant" concentrations?

Eckenhoff RG, Johansson JS

Publication Types:

• Letter

PMID: 11767771, UI: 21617884

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Anesthesiology 2001 Dec;95(6):1528-30

A novel method of one-lung isolation using a double endobronchial blocker technique.

Amar D, Desiderio DP, Bains MS, Wilson RS

Department of Anesthesiology, Memorian Sloan-Kettering Cancer Center, Weill Medical College of Cornell University, New York, New York 10021, USA. amard@mskcc.org

PMID: 11748418, UI: 21614296

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Anesthesiology 2001 Dec;95(6):1521-3

Continuous posterior lumbar plexus block for acute postoperative pain control in young children.

Sciard D, Matuszczak M, Gebhard R, Greger J, Al-Samsam T, Chelly JE

Memorial Hermann Hospital, Houston, Texas, USA.

PMID: 11748415, UI: 21614293

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Anesthesiology 2001 Dec;95(6):1519-21

Persistent phrenic nerve paralysis following interscalene brachial plexus block.

Robaux S, Bouaziz H, Boisseau N, Raucoules-Aime M, Laxenaire MC

Department of Anesthesiology and Critical Care, Central University Hospital, Nancy, France.

PMID: 11748414, UI: 21614292

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Anesthesiology 2001 Dec;95(6):1485-91

Cardiopulmonary bypass induces neurologic and neurocognitive dysfunction in the rat.

Mackensen GB, Sato Y, Nellgard B, Pineda J, Newman MF, Warner DS, Grocott HP

Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina 27710, USA.

BACKGROUND: Neurocognitive dysfunction is a common complication of cardiac surgery using cardiopulmonary bypass (CPB). Elucidating injury mechanisms and developing neuroprotective strategies have been hampered by the lack of a suitable long-term recovery model of CPB. The purpose of this study was to investigate neurologic and neurocognitive outcome after CPB in a recovery model of CPB in the rat. METHODS: Fasted rats (n = 10) were subjected to 60 min of normothermic (37.5 degrees C) nonpulsatile CPB using a roller pump and a membrane oxygenator. Sham-operated controls (n = 10) were not subjected to CPB. Neurologic outcome was assessed on days 1, 3, and 12 after CPB using standardized functional testing. Neurocognitive outcome, defined as the time (or latency) to finding a submerged platform in a Morris water maze (an indicator of visual-spatial learning and memory), was evaluated daily from post-CPB days 3-12. Histologic injury in the hippocampus was also evaluated. RESULTS: Neurologic outcome was worse in the CPB versus the sham-operated controls at all three measurement intervals (P < 0.001). The CPB group also had longer water maze latencies compared with the sham-operated controls (P = 0.004), indicating significant neurocognitive dysfunction after CPB. No difference in histologic injury between groups was observed. CONCLUSIONS: CPB caused both neurologic and neurocognitive impairment in a rodent recovery model. This model could potentially facilitate the investigation of CPB-related injury mechanisms and possible neuroprotective interventions.

PMID: 11748410, UI: 21614288

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Anesthesiology 2001 Dec;95(6):1380-8

Brain expression of inducible cyclooxygenase 2 messenger RNA in rats undergoing cardiopulmonary bypass.

Hindman BJ, Moore SA, Cutkomp J, Smith T, Ross-Barta SE, Dexter F, Brian JE Jr

Department of Anesthesia, University of Iowa, College of Medicine, Iowa City, USA. Brad-Hindman@uiowa.edu

BACKGROUND: We hypothesized that systemic proinflammatory cytokines or endotoxemia, or both, associated with cardiopulmonary bypass (CPB) would increase expression of inducible cyclooxygenase (COX-2) or inducible nitric oxide synthase (iNOS) messenger RNA (mRNA), or both, in brain. METHODS: Isoflurane-anesthetized Sprague-Dawley rats were randomly selected for CPB (n = 6) or sham surgery (n = 6). All animals underwent tracheotomy and controlled ventilation, arterial and venous pressure monitoring, insertion of a jugular venous outflow catheter, insertion of a subclavian arterial inflow catheter, systemic anticoagulation (500 U/kg heparin) and, except during CPB, servoregulation of pericranial temperature at 37.5 degrees C. Animals selected for CPB underwent 1 h of CPB at 165 ml x kg(-1) x min(-1) (31.8 +/- 0.2 degrees C), whereas animals having sham surgery underwent no intervention during this interval. Thereafter, all animals were given protamine and remained anesthetized for 4 more h. Brain and liver COX-2 and iNOS mRNA expression were determined by a ribonuclease protection assay with ribosomal L32 mRNA as a loading control. Arterial blood was analyzed for interleukin 1beta, interleukin 6, and endotoxin concentrations. RESULTS: Endotoxin concentrations did not increase above baseline values in either group. At 4 h after the CPB interval, interleukin 6 concentrations were significantly greater in CPB animals (101 +/- 45 pg/ml) versus sham animals (44 +/- 17 pg/ml) (P = 0.025). Brain COX-2 expression was significantly greater in CPB animals (0.36 +/- 0.11) versus shams (0.19 +/- 0.08) (P = 0.013). Brain COX-2 expression correlated with interleukin 6 concentration 4 h after CPB (r = 0.91; P = 5 x 10(-5)). In brain, iNOS mRNA was not detected in any animal. Cardiopulmonary bypass animals had only trace COX-2 and iNOS mRNA induction in liver. CONCLUSIONS: Cardiopulmonary bypass was associated with increased systemic interleukin 6 concentrations and increased brain COX-2 expression.

PMID: 11748396, UI: 21614274

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Anesthesiology 2001 Dec;95(6):1362-70

Are estimates of MAC reliable?

Paul M, Fisher DM

Department of Anesthesia, University of California, San Francisco, USA.

BACKGROUND: Potency of inhaled anesthetics (minimum alveolar concentration [MAC]) is typically studied in humans using an "up-down" approach in which the (quantal) response to skin incision is assessed only once for each individual, so that each individual's MAC is never determined. The authors examined the influence of interindividual variability and study design issues (e.g., the number of patients enrolled in a study) on the accuracy of MAC estimates. METHODS: The typical sequence of a MAC study was simulated. The authors varied and tested the impact of several factors: anesthetic concentration used to start a study; number of "crossovers" (successive patients having different responses to skin incision) to terminate a study; concentration increment between consecutive patients; interindividual variability; and "measurement error." For each factor, simulations were replicated 500 times, and the resulting estimates were summarized. RESULTS: Starting an experiment below or above the "true" value led to slightly biased MAC estimates; in contrast, variability was underestimated with starting concentrations close to the true value. More than six crossovers improved MAC estimates minimally but increased variability estimates toward true values. A larger increment size affected MAC minimally and increased variability estimates toward true values. A larger interindividual variability led to more "outlier" estimates for MAC. Under many conditions, several of 500 replicates yielded MAC estimates that deviated more than 10% or even more than 25% from the "true" value. CONCLUSION: Individual experiments may yield inaccurate MAC estimates. This inaccuracy is minimized as the number of crossovers increases; however, improvement diminishes as the number of crossovers exceeds six.

Publication Types:

• Clinical trial

PMID: 11748393, UI: 21614271

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Anesthesiology 2001 Dec;95(6):1346-50

Spinal ropivacaine for cesarean section: a dose-finding study.

Khaw KS, Ngan Kee WD, Wong EL, Liu JY, Chung R

Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, SAR, China. KimKhaw@cuhk.edu.hk

BACKGROUND: The dose-response relation for spinal ropivacaine is undetermined, and there are few data available for obstetric patients. METHODS: In a prospective, randomized, double-blind investigation, the authors studied 72 patients undergoing elective cesarean delivery. An epidural catheter was placed at the L2-L3 vertebral interspace. Lumbar puncture was then performed at the L3-L4 vertebral interspace, and patients were randomized to receive a dose of spinal ropivacaine diluted to 3 ml with normal saline: 10 mg (n = 12), 15 mg (n = 20), 20 mg (n = 20), or 25 mg (n = 20). Sensory changes assessed by ice and pin prick and motor changes assessed by modified Bromage score were recorded at timed intervals. A dose was considered effective if an upper sensory level to pin prick of T7 or above was achieved and epidural supplementation was not required intraoperatively. RESULTS: Anesthesia was successful in 8.3, 45, 70, and 90% of the 10-, 15-, 20-, and 25-mg groups, respectively. A sigmoid dose-response curve and a probit log dose-response plot were obtained, and the authors determined the ED50 (95% confidence interval) to be 16.7 (14.1-18.8) mg and the ED95 (95% confidence interval) to be 26.8 (23.6-34.1) mg. Duration of sensory and motor block and degree of motor block, but not onset of anesthesia, were positively related to dose. CONCLUSIONS: The ED50 and estimated ED95 for spinal ropivacaine were 16.7 and 26.8 mg, respectively. Ropivacaine is a suitable agent for spinal anesthesia for cesarean delivery.

Publication Types:

• Clinical trial
• Randomized controlled trial

PMID: 11748390, UI: 21614268

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Anesthesiology 2001 Dec;95(6):1323-8

Differential sensitivity of abdominal muscles and the diaphragm to mivacurium: an electromyographic study.

Kirov K, Motamed C, Dhonneur G

Department of Anesthesiology and Surgical Intensive Care Unit, Henri Mondor University Hospital, Paris XII School of Medicine, Creteil, France.

BACKGROUND: Respiratory muscles are considered to be more resistant to muscle relaxants as compared with peripheral muscles. However, the relative sensitivity of respiratory muscles participating to the pump function has not been compared. We used electromyography to compare pharmacodynamic parameters of the diaphragm and abdominal muscles after mivacurium. METHODS: Forty adults undergoing elective surgery were randomly allocated in five dosing groups of mivacurium (50, 100, 150, 200, and 250 microg/kg). Patients anesthetized with propofol and fentanyl underwent intubation without relaxants. Anesthesia was maintained with nitrous oxide and propofol. The right phrenic nerve, the left 10th intercostal nerve, and the ulnar nerve were stimulated. Electromyography of the diaphragm and abdominal muscles was recorded from surface electrodes. Mechanomyography was used to measure adductor pollicis evoked contraction. After a 5-min stable recording period, patients received a single intravenous bolus (20 s) dose of mivacurium. By using log dose-probit effect regression analysis, dose-response curves were constructed. Effective doses and 95% confidence intervals were derived for the diaphragm and abdominal muscles and were compared. RESULTS: The dose-response regression line of abdominal muscles differed from that of the diaphragm. Calculated ED50 and ED90 were higher for the diaphragm than for the abdominal muscles (104 [82-127] and 196 [177-213] microg/kg, and 67 [51-82] and 161 [143-181] microg/kg, respectively). The onset of block was faster and recovery of control responses were shorter at the diaphragm than at the abdominal muscles. CONCLUSION: Diaphragm and abdominal muscles have differential sensitivity to mivacurium. The diaphragm is more resistant to mivacurium than abdominal muscles are.

Publication Types:

• Clinical trial

PMID: 11748387, UI: 21614265

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Anesthesiology 2001 Dec;95(6):1311-2

Smiles, kudos, and comments.

Warner MA, Forbes RB, Canady JW

Publication Types:

• Comment
• Editorial

PMID: 11748384, UI: 21614262

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Br J Anaesth 2001 Aug;87(2):320-1

Use of pre-emptive vasopressors for spinal anaesthesia-induced hypotension during Caesarean section.

Heidemann BH, Clark VA

Publication Types:

• Letter

PMID: 11780169, UI: 21577435

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Br J Anaesth 2001 Aug;87(2):320

Incidence of awareness in total intravenous anaesthesia.

Sandin R

Publication Types:

• Letter

PMID: 11780168, UI: 21577434

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Br J Anaesth 2001 Aug;87(2):323-4

ProSeal laryngeal mask airway use for prolonged middle ear surgery.

Nicholls M

Publication Types:

• Letter

PMID: 11721708, UI: 21577438

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Br J Anaesth 2001 Aug;87(2):321-2

Epidural catheter associated duritis.

Imison A

Publication Types:

• Letter

PMID: 11721706, UI: 21577436

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Br J Anaesth 2001 Aug;87(2):295-8

Primary pulmonary hypertension in pregnancy; a role for novel vasodilators.

Monnery L, Nanson J, Charlton G

Department of Anaesthesia, Dorset County Hospital, Williams Avenue, Dorchester DT1 2JY, UK.

We describe the case of a 28-week pregnant woman presenting with severe primary pulmonary hypertension (PPH). She had an elective Caesarean section under general anaesthesia at 32 weeks gestation. Pulmonary artery pressures (PAP) measured from a pulmonary artery catheter before anaesthesia were in excess of 100 mm Hg. Intraoperative nitric oxide was used to reduce PAP. After the delivery of a healthy infant PAP was controlled with nebulized iloprost and a prostacyclin infusion. Seven days later she was discharged from intensive care taking an oral calcium antagonist and warfarin. She developed intractable right heart failure and died 14 days after delivery. Despite increasing experience in the use of drugs to reduce PAP, the clinical course of pregnancy complicated by severe PPH is usually fatal.

PMID: 11493507, UI: 21384819

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Br J Anaesth 2001 Aug;87(2):229-36

Cerebral hypoperfusion in immediate postoperative period following coronary artery bypass grafting, heart valve, and abdominal aortic surgery.

Millar SM, Alston RP, Andrews PJ, Souter MJ

Department of Anaesthesia, The Alfred Hospital, Prahran Melbourne, Victoria, Australia.

Perioperative levels of jugular bulb oxyhaemoglobin saturation (Sj(O(2))) and lactate concentration (Lj), and postoperative duration of Sj(O(2))<50% were compared between patients undergoing coronary artery bypass grafting (CABG) (n=86), heart valve (n=14) and abdominal aortic (n=16) surgery. Radial artery and jugular bulb blood samples were aspirated after induction of anaesthesia, during re-warming on cardiopulmonary bypass (CPB) (36 degrees C), on arrival in the intensive care unit (ICU) and, subsequently, at 1, 2 and 6 h after ICU admission. Most patients having heart surgery were hypocapnic at 36 degrees C on CPB. Following CABG and heart valve surgery, many patients were hypocapnic whereas after abdominal aortic surgery, most were hypercapnic. During CPB and postoperatively, Sj(O(2)) and Lj were significantly correlated to Pa(CO(2)) and the arterial concentration of lactate (La) respectively (P<0.05). After correction for arterial carbon dioxide tension (Pa(CO(2))) and La, there were no significant changes in Sj(O(2)) or Lj on CPB. Postoperatively, having corrected for Pa(CO(2)), there were significant effects on Sj(O(2)) over all groups as a result of time from surgery (P<0.001) and its interaction with operation type (P<0.001). Following correction for La, there were no postoperative effects on Lj. No significant differences (P=0.2) in duration of Sj(O(2))<50% existed between patients undergoing CABG (1054 (82) min), abdominal aortic (893 (113) min) and heart valve (1073 (91) min) surgery. The lack of significant reciprocal effects on Lj combined with the frequency of hypocapnia and strong influence of Pa(CO(2))()on Sj(O(2)), suggest that Sj(O(2))<50% during CPB and after cardiac surgery represents hypoperfusion as a consequence of hypocapnia rather than cerebral ischaemia.

PMID: 11493494, UI: 21384806

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Br J Anaesth 2001 Aug;87(2):207-11

Manoeuvres used to clear the airway during fibreoptic intubation.

Durga VK, Millns JP, Smith JE

Department of Anaesthesia, University Hospital Birmingham, Selly Oak Hospital, Birmingham B29 6JD, UK.

Fibreoptic orotracheal endoscopy under general anaesthesia may be more difficult to perform if the upper airway cannot be fully cleared. We have studied the effectiveness of jaw thrust, lingual traction and the application of both manoeuvres simultaneously, in opening up the orolaryngeal airspace in 30 ASA group 1 or 2 patients aged between 16 and 70 yr undergoing elective general surgery requiring orotracheal intubation. Airway clearance was assessed fibreoptically at soft palate level by observing whether or not the uvula or soft palate was apposed to the base of the tongue, and at epiglottic level by observing whether or not the epiglottis was apposed to the posterior pharyngeal wall. Lingual traction with Duval's forceps cleared the tongue away from the uvula and soft palate significantly more times than did jaw thrust (P<0.05). Jaw thrust cleared the epiglottis away from the posterior pharyngeal wall more frequently than did lingual traction (P=0.052). Applying both jaw thrust and lingual traction simultaneously cleared the airway at both soft palate and epiglottic level in every patient. When used alone, jaw thrust and lingual traction fail to produce full airway clearance in a significant number of patients. Combined jaw thrust and lingual traction clears the airway more effectively but requires two assistants.

Publication Types:

• Clinical trial
• Controlled clinical trial

PMID: 11493491, UI: 21384803

Br J Pharmacol 2002 Jan 1;135(1):55-64

The antiarrhythmic effects of ischaemic preconditioning in anaesthetized dogs are prevented by atropine; role of changes in baroreceptor reflex sensitivity.

Babai L, Papp JG, Parratt JR, Vegh A A

Department of Pharmacology and Pharmacotherapy, University of Szeged, Albert Szent-Gyorgyi Faculty of Medicine, Dom ter 12, P.O. Box 427, H-6701 Hungary. Research Unit for Cardiovascular Pharmacology, Hungarian Academy of Sciences, University of Szeged, Albert Szent-Gyorgyi Faculty of Medicine, Dom ter 12, P.O. Box 427, H-6701 Hungary. Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 0NR.

[Record supplied by publisher]

Dogs, anaesthetized with chloralose and urethane, were subjected to a 25 min occlusion of the left anterior descending coronary artery. This resulted in ventricular ectopic activity, a reduction in baroreflex sensitivity (BRS, measured following the intravenous administration of phenylephrine), elevations in the epicardial ST-segment and increases in the degree of inhomogeneity of electrical activation, both measured from the ischaemic region of the left ventricular wall. These changes were markedly reduced when the 25 min occlusion was preceded, 20 min earlier, by a 5 min (preconditioning) occlusion of the same coronary artery (e.g. VF during ischaemia reduced from 40% in the controls to 0%; P<0.05; BRS increased from 1.22+/-0.23 pre-occlusion to 1.61+/-0.25 mmHg ms(-1) post-occlusion in preconditioned dogs; cf. 1.28+/-0.29 to 0.45+/-0.12 mmHg ms(-1) respectively in the controls, P<0.05). These beneficial effects of preconditioning were prevented by the administration, 10 min prior to the 25 min coronary artery occlusion, of atropine (1 mg kg(-1) i.v. followed by a continuous infusion of 0.04 mg kg(-1) h(-1)). For example, VF during occlusion was increased from 0% in the preconditioned dogs to 40% (P<0.05) in the presence of atropine and BRS was again reduced during occlusion (from 1.75+/-0.29 to 0.30+/-0.08 mmHg ms(-1); P<0.05). We conclude that preconditioning reduces arrhythmia severity during ischaemia by favourably modifying cardiac autonomic receptor mechanism through enhancing vagal influences.

PMID: 11786480

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Can J Anaesth 2002 Jan;49(1):90-1

Images in Anesthesia: Bilateral pneumothorax following tracheal extubation.

Badaoui R, El Kettani C, Ouendo M, Fikri M, Montravers P

Amiens France.

[Medline record in process]

PMID: 11782335, UI: 21642023

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Can J Anaesth 2002 Jan;49(1):81-3

Anesthetic management for a patient with Jansky-Bielschowsky disease : [L'anesthesie d'une patiente atteinte d'idiotie amaurotique de type Bielschowsky].

Yamada Y, Doi K, Sakura S, Saito Y

Department of Anesthesiology, Shimane Medical University, Izumo, Japan.

[Medline record in process]

PURPOSE: To describe the anesthetic management of a patient with Jansky-Bielschowsky disease (JBD), the late infantile form of neuronal ceroid lipofuscinosis, characterized by dementia, severe and drug resistant grand mal, myoclonic seizures, and blindness. Clinical features: A 14-yr-old girl with JBD was scheduled for resection of a gingival tumour and an infected sinus in the sacral area. Her preanesthetic examination revealed extreme muscle atrophy and dementia. Grand mal, myoclonic seizures, and upper airway obstruction were frequent. Following iv induction with thiamylal, anesthesia was maintained with sevoflurane, N(2)O and O(2). Her trachea was intubated without using muscle relaxants. Muscle relaxants were not used during the operation. Apart from an intractable hypothermia, the intraoperative course was uneventful. The emergence of anesthesia was smooth, except for persisting seizures. CONCLUSION: General anesthesia using thiamylal and sevoflurane provided satisfactory conditions during operation in a patient with JBD. Intraoperative hypothermia required particular attention.

PMID: 11782333, UI: 21642021

Can J Anaesth 2002 Jan;49(1):67-71

Lidocaine with fentanyl, compared to morphine, marginally improves postoperative epidural analgesia in children : [Une combinaison de lidocaine et de fentanyl, comparee a la morphine, ameliore peu l'analgesie peridurale postoperatoire chez les enfants].

Reinoso-Barbero F, Saavedra B, Hervilla S, de Vicente J, Tabares B, Gomez-Criado MS

Departamentos de Anestesiologia y Farmacologia Clinica Hospital Universitario "La Paz" Facultad de Medicina Universidad Autonoma de Madrid Madrid Spain.

[Record supplied by publisher]

PURPOSE: To compare the epidural administration of fentanyl (1 &mgr;g*mL(-1)) combined with lidocaine 0.4% to preservative-free morphine for postoperative analgesia and side effects in children undergoing major orthopedic surgery. METHODS: In a prospective, double-blind study, 30 children, ASA I-II, 2-16-yr-old, were randomly allocated to receive immediately after surgery either epidural F-L (epidural infusion at a rate of 0.1-0.35 mL*kg(-1)*hr(-1) of 1 &mgr;g*mL(-1) of fentanyl and lidocaine 0.4%) or epidural M (bolus of 20 &mgr;g*kg(-1) of morphine in 0.5 mL*kg(-1) saline every eight hours). Both groups received 40 mg*kg(-1) of iv metamizol (dipyrone) every six hours. In the F-L Group, blood samples were taken on the second and third postoperative day to determine total lidocaine concentrations. Adequacy of analgesia using adapted pediatric pain scales (0-10 score) and side-effects were assessed every eight hours postoperatively. RESULTS: Resting pain scores were under 4, 95% of the time in the F-L Group and 87% of the time in the M Group (Chi square=4.674, P <0.05). The frequency of complications was very similar in both groups. The F-L Group total plasma lidocaine concentrations were directly related to the dose received, and below the toxic range in all patients. CONCLUSIONS: Postoperative epidural fentanyl with lidocaine infusion provides slightly better analgesia than conventional bolus administration of epidural morphine. Side-effects or risk of systemic toxicity were not augmented by the addition of lidocaine to epidural opioids.

PMID: 11782331

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Can J Anaesth 2002 Jan;49(1):49-56

Examining the evidence in anesthesia literature: a survey and evaluation of obstetrical postdural puncture headache reports : [Examen de la preuve dans la documentation sur l'anesthesie : enquete et evaluation des articles sur les cephalees obstetricales post-ponction durale].

Choi PT, Galinski SE, Lucas S, Takeuchi L, Jadad AR

Department of Anesthesia, St. Joseph's Healthcare and McMaster University, Hamilton, Ontario, Canada. Toronto, Ontario, Canada.

[Medline record in process]

PURPOSE: To describe a bibliographic database on the literature of postdural puncture headache (PDPH) in the obstetrical population, to describe the research architecture in this field, and to evaluate the quality of case-control studies, cohort studies, and controlled clinical trials on PDPH. METHODS: Computerized bibliographic searches, citation review, and hand searches were conducted to find all relevant citations on incidence, clinical course, prevention, or treatment of PDPH in parturients. The study design and topic(s) covered by each study were evaluated. Case-control studies and cohort studies were evaluated using the Quality Index; clinical trials were evaluated using the Jadad scale. RESULTS: One hundred ninety-six relevant citations were published between 1949 and 1999. Research on PDPH has been increasing rapidly with the majority of studies published in the 1990's. Incidence and prevention were the focus of over half of all citations. Optimal study designs were infrequently utilized. The methodological quality was poor for observational studies (Quality Index 10/29) and clinical trials (Jadad scale 2/5). CONCLUSION: Although the amount of research on PDPH in parturients is increasing, use of optimal study designs and improvement in methodology is needed.

PMID: 11782328, UI: 21642016

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Can J Anaesth 2002 Jan;49(1):46-8

Best evidence in anesthetic practice: Prognosis: the Apgar score predicts 28-day neonatal mortality.

Macarthur A, Halpern S

Toronto, Ontario.

[Medline record in process]

PMID: 11782327, UI: 21642015

Can J Anaesth 2002 Jan;49(1):32-45

A systematic review of adjuncts for intravenous regional anesthesia for surgical procedures : [Etude methodique des traitements d'appoint a l'anesthesie regionale intraveineuse pendant les interventions chirurgicales].

Choyce A, Peng P

Departments of Anesthesia, King's College Hospital, Denmark Hill, London, UK and the Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.

[Record supplied by publisher]

PURPOSE: To review the use of adjuncts to intravenous regional anesthesia (IVRA) for surgical procedures in terms of their intraoperative effects (efficacy of block and tourniquet pain) and postoperative analgesia. SOURCE: A systematic search (Medline, Embase, reference lists) for randomized, controlled and double-blinded studies using adjuncts to IVRA for surgical procedures was conducted. Data were collected on intraoperative effects (onset/offset and quality of block and tourniquet pain), postoperative effects (pain intensity and analgesic consumption) and side effects recorded. Statistical significance as indicated in the original report and likely clinical relevance were taken into account to arrive at a judgment of overall benefit. Principal findings: Twenty-nine studies met all inclusion criteria. Data on 1,217 study subjects are included. Adjuncts used were opioids (fentanyl, meperidine, morphine, sufentanil), tramadol, non-steroidal anti-inflammatory drugs (NSAIDs; ketorolac, tenoxicam, acetyl-salicylate), clonidine, muscle relaxants (atracurium, pancuronium, mivacurium), alkalinization with sodium bicarbonate, potassium and temperature. There is good evidence to recommend NSAIDs in general and ketorolac in particular, for improving postoperative analgesia. Clonidine 1 &mgr;g*kg (-1) also appears to improve postoperative analgesia and prolong tourniquet tolerance. Opioids are poor by this route; only meperidine 30 mg or more has substantial postoperative benefit but at the expense of postdeflation nausea, vomiting and dizziness. Muscle relaxants improve intraoperative motor block and aid fracture reduction. CONCLUSION: Using NSAIDs or clonidine as adjuncts to IVRA improves postoperative analgesia and muscle relaxant improves motor block.

PMID: 11782326

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Can J Anaesth 2002 Jan;49(1):1-4

Anesthesiology and hyperbaric medicine/Anesthesiologie et medecine hyperbare.

LeDez KM

[Medline record in process]

PMID: 11782320, UI: 21642008

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Can J Anaesth 2001 Nov;48(10):1015-9

The intubating laryngeal mask airway in severe ankylosing spondylitis.

Lu PP, Brimacombe J, Ho AC, Shyr MH, Liu HP

Department of Anesthesia, Chang Gung Memorial Hospital, Taoyuan Hsien.

PURPOSE: To evaluate the use of inhalational induction followed by intubation through the intubating laryngeal mask (ILM) for patients with severe ankylosing spondylitis undergoing elective surgery who prefer airway management under anesthesia. METHODS: Nine patients undergoing a total of 11 procedures were enrolled in the study. Fentanyl 2 microg*kg(-1), midazolam 0.035 mg*kg(-1) and sevoflurane in oxygen 100% were used for induction. The ILM was inserted when the end-tidal sevoflurane concentration reached 3%. After an effective airway was established, atracurium 0.5 mg*kg(-1) was given. A polyvinyl chloride tube in the reversed position using a blind technique was used to intubate the trachea. RESULTS: The ILM provided an effective airway on 11/11 occasions at the first attempt. Intubation was successful at the first attempt on 7/11 occasions, at the second attempt on 2/11 and at the third attempt in 1/11. Intubation failed in one patient. The mean (range) minimal oxygen saturation was 99.4% (97-100%). There were no problems with ILM removal. CONCLUSION: Inhalational induction followed by ILM insertion and blind intubation is a reasonable option in patients with severe ankylosing spondylitis undergoing elective surgery who prefer airway management under anesthesia.

PMID: 11698322, UI: 21554835

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Can J Anaesth 2001 Nov;48(10):1000-10

Preemptive analgesia I: physiological pathways and pharmacological modalities.

Kelly DJ, Ahmad M, Brull SJ

Department of Anaesthesia, Cork University Hospital, Wilton, Cork, Ireland.

PURPOSE: This two-part review summarizes the current knowledge of physiological mechanisms, pharmacological modalities and controversial issues surrounding preemptive analgesia. SOURCE: Articles from 1966 to present were obtained from the MEDLINE databases. Search terms included: analgesia, preemptive; neurotransmitters; pain, postoperative; hyperalgesia; sensitization, central nervous system; pathways, nociception; anesthetic techniques; analgesics, agents. Principal findings: The physiological basis of preemptive analgesia is complex and involves modification of the pain pathways. The pharmacological modalities available may modify the physiological responses at various levels. Effective preemptive analgesic techniques require multi-modal interception of nociceptive input, increasing threshold for nociception, and blocking or decreasing nociceptor receptor activation. Although the literature is controversial regarding the effectiveness of preemptive analgesia, some general recommendations can be helpful in guiding clinical care. Regional anesthesia induced prior to surgical trauma and continued well into the postoperative period is effective in attenuating peripheral and central sensitization. Pharmacologic agents such as NSAIDs (non-steroidal anti-inflammatory drugs) opioids, and NMDA (N-methyl-D-aspartate) - and alpha-2-receptor antagonists, especially when used in combination, act synergistically to decrease postoperative pain. CONCLUSION: The variable patient characteristics and timing of preemptive analgesia in relation to surgical noxious input requires individualization of the technique(s) chosen. Multi-modal analgesic techniques appear most effective.

Publication Types:

• Review
• Review, tutorial

PMID: 11698320, UI: 21554833

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Eur J Anaesthesiol 2001 Dec;18(12):836-8

The effect of rocuronium on intraocular pressure: a comparison with succinylcholine.

Mitra S, Gombar KK, Gombar S

Publication Types:

• Clinical trial
• Letter
• Randomized controlled trial

PMID: 11737185, UI: 21600897

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Eur J Anaesthesiol 2001 Dec;18(12):829-32

Sudden unconsciousness during a lesser occipital nerve block in a patient with the occipital bone defect.

Okuda Y, Matsumoto T, Shinohara M, Kitajima T, Kim P

First Department of Anaesthesiology, Dokkyo University School of Medicine, Tochigi, 321-0293, Japan. y-okuda@dokkyomed.ac.jp

Occipital nerve block is usually considered to be a very simple and safe regional anaesthetic technique. We describe a case of sudden unconsciousness during a lesser occipital nerve block in a patient with an occipital bone defect. A 63-year-old man complained of headache, which was localized to the right occipital region. A right lesser occipital nerve block with a local anaesthetic was performed for treatment. During the lesser occipital nerve block, the patient suddenly became disturbed and lost consciousness. Two hours after the incident, the patient was fully awake without neurological sequelae. He had previously undergone a microvascular decompression for right trigeminal neuralgia. The patient had a bone defect following craniotomy. We believed that the loss of consciousness during lesser nerve block may be due to a subarachnoid injection. Occipital nerve block is relatively contraindicated in the presence of a bone defect.

PMID: 11737183, UI: 21600895

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Eur J Anaesthesiol 2001 Dec;18(12):789-97

The midazolam-induced paradox phenomenon is reversible by flumazenil. Epidemiology, patient characteristics and review of the literature.

Weinbroum AA, Szold O, Ogorek D, Flaishon R

Post Anesthesia Care Unit, Tel Aviv Sourasky Medical Center, 6 Weizman St, Tel Aviv 64239, Israel. draviw@tasmc.health.gov.il

BACKGROUND AND OBJECTIVE: Midazolam may occasionally precipitate hostility and violence instead of tranquility. We characterized these episodes, their rate of occurrence, the potential paradoxical responders and possible predisposing circumstances among patients undergoing lower body surgery under spinal or epidural anaesthesia and midazolam sedation. PATIENTS AND METHODS: Fifty-eight patients who fulfilled the study entry criteria and who underwent surgery within a 3-month period in a large metropolitan, university-affiliated hospital were enrolled. Sedation and restlessness in all patients were controlled by midazolam administered intravenously by the attending anaesthesiologist; these parameters were later objectively confirmed by recorded actigrams. If "paradoxical" events occurred, flumazenil 0.1 mg 10 s-1 was injected until the aberrant behaviour ceased. Patients with paradoxical reactions were later compared with matched control patients selected from the study group to identify epidemiological characteristics. RESULTS: The incidence of paradoxical events was 10.2% (six out of 58 patients, confidence limits 2.3-18.3%) and they occurred 45-210 min after sedation started; the only independent predictor was an age older than that of the entire study group. The mean cumulative and per weight doses of midazolam were similar for both the experimental and the study groups of patients: 7.3 +/- 2.8 to 10.1 +/- 3.6 mg, and 0.1 +/- 0.04 to 0.12 +/- 0.05 mg kg-1. Flumazenil 0.2-0.3 mg (range 0.1-0.5 mg) effectively stopped the midazolam-induced paradoxical activity within 30 s and surgery continued uneventfully. CONCLUSIONS: Flumazenil completely reverses midazolam-induced paradoxical reactions and they are more frequent in older patients.

Publication Types:

• Review
• Review, academic

PMID: 11737177, UI: 21600889

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Eur J Pharmacol 2001 Sep 28;428(1):113-9

Effects of furosemide on the tubular reabsorption of nitrates in anesthetized dogs.

Rahma M, Kimura S, Yoneyama H, Kosaka H, Nishiyama A, Fukui T, Abe Y

Department of Pharmacology, Kagawa Medical University, Japan. yakuri@kms.ac.jp

[Medline record in process]

The present study was performed to determine the tubular sites of nitrite and nitrate (NO) reabsorption and the effects of furosemide on the renal handling of NOx in anesthetized dogs, using renal clearance and stop-flow methods. Furosemide (2 mg/kg, i.v.) increased the urinary excretion rates of Na+ (U(Na+)V) and NOx (U(NOx)V) with a reduction of tubular reabsorption rates of Na+ and NOx. During inhibition of renal nitric oxide (NO) synthesis by an intrarenal infusion of L-nitro arginine (30 microg/kg-min), furosemide also increased U(NOx)V and decreased tubular reabsorption rate of NOx from 96.5+/-0.8% to 86.6+/-1.7%. An intravenous infusion of 10% mannitol (0.5 ml/kg-min) also increased both U(Na+)V and U(NOx)V. In addition, after furosemide administration or mannitol infusion. U(NOx)V was correlated with U(Na+)V. In stop-flow experiments, the distal dip in NOx curve was observed and the site of the dip in NOx curve was identical to that of Na+ curve. Furosemide shifted upward the U/P(Na+)/U/P(Cr) and U/P(NOx)/U/P(Cr) at the distal dip, indicating inhibition of Na+ and NOx reabsorption at distal tubules. These results indicate that more than 96% of the filtered NOx is reabsorbed in the renal tubules, and that the tubular handling of NOx is very close to that of Na+. In addition, the stop-flow experiments demonstrate that furosemide inhibited the reabsorption of NOx as well as Na+ at the distal tubule.

PMID: 11779027, UI: 21637311

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Pediatr Dent 2001 Sep-Oct;23(5):424-30

Comparing the safety, efficacy and recovery of intranasal midazolam vs. oral chloral hydrate and promethazine.

Dallman JA, Ignelzi MA Jr, Briskie DM

Department of Orthodontics and Pediatric Dentistry, University of Michigan School of Dentistry, USA.

PURPOSE: The purpose of this study was to compare the safety, efficacy and recovery time of intranasal midazolam spray administered using an atomizer to orally administered chloral hydrate and promethazine for the sedation of pediatric dental patients. METHODS: A randomized double-blind crossover study design was utilized in which 31 patients (mean age 41.8 months, range 26-58 months) underwent two restorative dental appointments. At one appointment, subjects received 0.2 mg/kg intranasal midazolam; at the other appointment subjects received 62.5 mg/kg chloral hydrate with 12.5 mg promethazine. Administered at each appointment was 25%-50% N(2)0/0(2). Physiologic parameters (heart rate, blood pressure, respiratory rate, oxygen saturation) and behavior assessments (crying, movement, sleep) using the Houpt Sedation Rating Scale were recorded at baseline and every five minutes during treatment. Overall behavior was assessed at baseline and at the end of treatment. Following treatment, a modified Vancouver Recovery Scale was used to determine the length of time it took each subject to meet established discharge criteria. RESULTS: There were no clinically significant differences in physiologic parameters, however a statistically significant decrease in systolic and diastolic blood pressure was observed in patients sedated with chloral hydrate/promethazine. There were no significant differences in behavior between groups. Patients sedated with intranasal midazolam slept less and recovered quicker than patients sedated with oral chloral hydrate/promethazine. CONCLUSIONS: Intranasal midazolam administered using an atomizer is as safe (as assessed by physiologic parameters) and effective (as assessed by behavior ratings) as oral chloral hydrate/promethazine for conscious sedation of pediatric dental patients.

Publication Types:

• Clinical trial
• Randomized controlled trial

PMID: 11699169, UI: 21556487