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(Technical Communication)

PEDIATRIC ANESTHESIA:

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ANESTHETIC PHARMACOLOGY:

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Inhaled Anesthetics and Immobility: Mechanisms, Mysteries, and Minimum Alveolar Anesthetic Concentration (Review Article)

ª¯¤j¸£½¤¶Ë®`/Orphanin FQ(N/OFQ)µ²¦X¦ìÂIªº¯SÂI

Characterization of Nociceptin/Orphanin FQ Binding Sites in Dog Brain Membranes (Review Article)

µw½¤¥~¥i¼Ö©w¹ï¦Ñ¹«À£¤O·P¨ü¾¹¥æ·P¯«¸g¤ÏÀ³ªº§í¨î¨Ì¿à²§¬tîÅ¿@«×

Epidural Clonidine Suppresses the Baroreceptor-Sympathetic Response Depending on Isoflurane Concentrations in Cats (Review Article)

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Midazolam-Induced Muscle Dysfunction and Its Recovery in Fatigued Diaphragm in Dogs (Review Article)

¦h¨F´¶¨Ú¥i¨Ï¨ßŸìH­°§C¨Ã§e¾¯¶q¬ÛÃö©Ê

Doxapram Produces a Dose-Dependent Reduction in the Shivering Threshold in Rabbits (Review Article)

2-Bromomelationinªº¶Ê¯v©MÂíµh®ÄÀ³

The Hypnotic and Analgesic Effects of 2-Bromomelatonin (Review Article)

TECHNOLOGY, COMPUTING, AND SIMULATION:

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(¤ý¥ß¤¤ Ķ ²ø¤ß¨} ®Õ¡^

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PAIN MEDICINE:

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Defining Neuropathic Pain (Medical Intelligence)

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Does Pain Relief Improve Pain Behavior and Mood in Chronic Pain Patients? (Medical Intelligence)

¯«¸gÃþ©T¾JÃĪ«ªºÂíµh§@¥Î¡Gªüªk¨FÀs©Mªüªk¦hÀs¹ï¶Ü°ØÃþÂíµhÃĪº¼W±j§@¥Îªº¤ñ¸û

Antinociceptive Properties of Neurosteroids: A Comparison of Alphadolone and Alphaxalone in Potentiation of Opioid Antinociception (Medical Intelligence)

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(¤ý¤h¹p Ķ ²ø¤ß¨} ®Õ¡^

The Antinociceptive Effect of Nalbuphine and Its Long-Acting Esters in Rats (Medical Intelligence)

¦b»¶´Ô¯À¤Þ°_µhı¹L±Óªº¦ÛÄ@ªÌ¤¤ÀR¯ß¨Ï¥Î¹p¦Ìªâ¤Ó¥§·|²£¥ÍºMÃĩʪºµhı¹L±Ó

Intravenous Remifentanil Produces Withdrawal Hyperalgesia in Volunteers with Capsaicin-Induced Hyperalgesia (Medical Intelligence)

¬t©K§Q¦h¹ï¶Ü°Ø¦Û±±Âíµh¯f¤Hªº¤î¦R§@¥Î¡GÀH¾÷¡A¹ï·Ó¡A¦hºØ¾¯¶q-®ÄÀ³ªº¬ã¨s¡C

The Antiemetic Efficacy of Droperidol Added to Morphine Patient-Controlled Analgesia: A Randomized, Controlled, Multicenter Dose-Finding Study (Medical Intelligence)

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The Effects of Postoperative Pain Management on Immune Response to Surgery (Medical Intelligence)

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Can Quantitative Sensory Testing Predict the Outcome of Epidural Steroid Injections in Sciatica? A Preliminary Study (Medical Intelligence)

CRITICAL CARE AND TRAUMA:

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NEUROSURGICAL ANESTHESIA:

µ¥À£°ª®ñª¬ºA¤U´ú¶q¤j¸£ªº®ñ¦X¡G¸£¥~¶Ë®É¨Ï¥Î²Õ´·L±´¤l¡Aªñ¬õ¥~½u¤À¥úÃè¤ÎÀVÀR¯ß¦å®ñ´ú©w¤TºØ§Þ³Nªº¤ñ¸û

¨ß¤l¼Ò«¬¤¤²Ó­M¶¡ÂHªþ¤À¤l-1¡]ICAM-1¡^ªº³æ§J¶©§ÜÅé¦bµw½¤¥~ªºªvÀø§@¥Î¡G²Ó­M¶¡ÂHªþ¤À¤l-1¡]ICAM-1¡^¤Þ°_¯á¯Á¯Ê¦åªº¾÷¨î

OBSTETRIC ANESTHESIA:

ÄY­«¥ý¥ü¤líw²£°ü¸y³Â¤À®Y®É§C¦åÀ£ªºµo¥Í²v¤Ö©ó°·±d²£°ü¡G«e¤©Ê¦î¦C¬ã¨s

¦b±ß´Á¤À®Y®ÉÀT¤ºª`®g25ugªâ¤Ó¥§¦X¥Î2.5mgªº­«¤ñ­«¥¬¤ñ¥d¦]»P¦X¥Îµ¥¤ñ­«¥¬¤ñ¥d¦]¬Û¤ñ©µªø¤FÂíµh®É¶¡

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REGIONAL ANESTHESIA:

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*Division of Anesthesiology, Department APSIC (Anesthesiology, Pharmacology & Surgical Intensive Care) and Division of Cardiology, Geneva University Hospitals, Switzerland

Anesth Analg 2003 97: 623-633.

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A number of drugs have been tested in clinical trials to decrease cardiac complications in patients undergoing noncardiac surgery. To compare the results of these studies, we conducted a quantitative systematic review. Medline, Embase, and Cochrane databases were searched for randomized trials that assessed myocardial ischemia, myocardial infarction, 30-day cardiac mortality, and adverse effects. Data were combined using a fixed-effect model and expressed as Peto odds ratios (OR) with 95% confidence interval (CI) and as numbers-needed-to-treat/harm (NNT/H). Twenty-one trials involving 3646 patients were included: 11 trials using s-blockers (6 drugs; 866 patients), 6 clonidine or mivazerol (614 patients), 3 diltiazem or verapamil (121 patients), and 1 nitroglycerin (45 patients). All trials had an inactive control; there were no direct comparisons. s-blockers decreased ischemic episodes during surgery (7.6% versus 20.2% with placebo; OR 0.32 [95% CI, 0.17¡V0.58]; NNT 8) and after surgery (15.2% versus 27.9% with control; OR 0.46 [95% CI, 0.26¡V0.81]; NNT 8). ₂-agonists decreased ischemia during surgery only (19.4% versus 32.8%; OR 0.47 [95% CI, 0.33¡V0.68]; NNT 7). s-blockers reduced the risk of myocardial infarction (0.9% versus 5.2%; OR 0.19 [95% CI, 0.08¡V0.48]; NNT 23) but only when 2 trials with high-risk patients were included. The effect of ₂-agonists on myocardial infarction was not significant (6.1% versus 7.3%; OR 0.85 [95% CI, 0.62¡V1.14]). s-blockers significantly decreased the risk of cardiac death from 3.9% to 0.8% (OR 0.25 [95% CI, 0.09¡V0.73], NNT 32). ₂-agonists significantly decreased the risk of cardiac death from 2.3% to 1.1% (OR 0.50 [95% CI, 0.28¡V0.91], NNT 83). For calcium channel blockers and nitroglycerin, evidence of any benefit was lacking. The most common adverse effect was bradycardia, which occurred in 24.5% of patients receiving a s adrenergic blocker versus 9.1% of controls (OR 3.76 [95% CI, 2.45¡V5.77], NNH 6).

Department of Anesthesiology, University of Pittsburgh Medical Center, Pennsylvania

Anesth Analg 2003 97: 648-649.

Venovenous bypass has improved patient survival and decreased morbidity and mortality in the field of orthotopic liver transplantation. The standard at many transplant centers is the use of the internal jugular percutaneous venovenous bypass cannulae (PVVBC) for venous return to the patient. Placement of these large (18F) PVVBC may lead to several complications and requires confirmation before use. Use of transesophageal echocardiography, an effective and rapid method to guide placement of the PVVBC and minimize potential complications associated with insertion of the device, is described.

Inhaled Anesthetics and Immobility: Mechanisms, Mysteries, and Minimum Alveolar Anesthetic Concentration (Review Article)

*Department of Anesthesia and Perioperative Care, University of California, San Francisco, California; Department of Anesthesiology, University of California, Davis, California; Columbia University, New York, New York; University of Texas, Austin, Texas; ||University of Pittsburgh, Pittsburgh, Pennsylvania; ?Stanford University, Palo Alto, California; #University of Toronto, Toronto, Canada; **Department of Anaesthesia, Harvard Medical School, Cambridge, Massachusetts; and Garvan Institute of Medical Research, Darlinghurst, Australia
Anesth Analg 2003 97: 718-740.

³q¹L¤À¤l¼Ò«¬¡B°ò¦]¤uµ{¡B¯«¸g¥Í²z¡B¯«¸gÃIJz©M°Êª«¹êÅçµ¥¤è­±ªº¬ã¨s¡A§Ú­Ì¹ï§l¤J³Â¾KÃijq¹L¹ï¯áÅ誺§@¥Î²£¥Í¨î°Êªº¾÷¨î¦³¤F§ó¦nªºÁA¸Ñ¡C³\¦h°tÅé©M¹qÀ£ªù±±Â÷¤l³q¹D¥i¯à°Ñ»P¤FMACªº½Õ¸`¡A¦Ó¤@¨Ç¯S®íªº®ò°ò»Ä³¡¦ì¥i¯à¬O½Õ¸`³¡¦ì¡CµM¦Ó¡A³q¹L¦bÅé¹êÅçµo²{¡A¤@¨Ç¨üÅé©Î³q¹D¥i¯à¤£°Ñ»P½Õ¸`¥þ³Â¨î°Ê§@¥Îªº½Õ¸`¡A³o¥]¬AGABAA¡BAch¡BK+¡B5-HT3¡Bªü¤ù¨üÅé©M₂-¨üÅé¿E°Ê¾¯µ¥¡C¨ä¥L¦p¥Ì®ò»Ä¡BNMDA¡B¶u³q¹Dµ¥ªº§@¥Î¡A«h»Ý­n¶i¤@¨BÅçÃÒ¡C

Studies using molecular modeling, genetic engineering, neurophysiology/pharmacology, and whole animals have advanced our understanding of where and how inhaled anesthetics act to produce immobility (minimum alveolar anesthetic concentration; MAC) by actions on the spinal cord. Numerous ligand- and voltage-gated channels might plausibly mediate MAC, and specific animo acid sites in certain receptors present likely candidates for mediation. However, in vivo studies to date suggest that several channels or receptors may not be mediators (e.g., -aminobutyric acid A, acetylcholine, potassium, 5-hydroxytryptamine-3, opioids, and ₂-adrenergic), whereas other receptors/channels (e.g., glycine, N-methyl-D-aspartate, and sodium) remain credible candidates.

Department of Anesthesiology, University of Tsukuba Institute of Clinical Medicine, Tsukuba City, Ibaraki, Japan

Anesth Analg 2003;97:755-758

Midazolam, widely used for sedation and anesthesia, decreases contractility in nonfatigued diaphragm; however, its effects on contractility in fatigued diaphragm that are implicated as a cause of respiratory failure have not been established. We therefore studied the effects of midazolam on diaphragm muscle function and recovery in fatigued diaphragm. Dogs were divided into three groups of eight each. In each group, diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20-Hz stimulation for 30 min. When fatigue was established, Group I received no study drug; Group II was infused with a sedative dose (0.1 mg ¡P kg^-1 ¡P h^-1) of midazolam; and Group III was infused with an anesthetic dose (0.5 mg ¡P kg^-1 ¡P h^-1) of midazolam. We assessed diaphragm muscle function (contractility and electrical activity) by transdiaphragmatic pressure (Pdi) and integrated electrical activity of the diaphragm (Edi). In the presence of fatigue, Pdi at low-frequency (20-Hz) stimulation decreased from baseline values (P < 0.05), Pdi at high-frequency (100-Hz) stimulation did not change, and Edi to each stimulus did not change. With an infusion of midazolam, in Groups II and III, Pdi at both stimuli and Edi at 100-Hz stimulation decreased from fatigued values (P < 0.05). The decrease in Pdi and Edi was more in Group III than in Group II (P < 0.05). At 60 min after the cessation of midazolam administration, in Group II, Pdi and Edi recovered from midazolam-induced values (P < 0.05) and returned to fatigued values. In Group III, Pdi and Edi did not change from midazolam-induced values. We conclude that midazolam causes, in a dose-related manner, diaphragm muscle dysfunction in fatigued canine diaphragm and that at a sedative dose, but not at an anesthetic dose, midazolam does not delay its recovery.

Departments of *Anesthesiology, Pediatrics, and Child Psychiatry, Yale University School of Medicine and Yale-New Haven Hospital, New Haven, Connecticut

Anesth Analg 2003 97: 772-775.

¤j¸£¥b²y¦P¨B¤Æ³Ìªñ³Q§@¬°´î¤Ö³N«eµJ¼{©M³N¤¤³Â¾KÃÄ¡BÂíµhÃĥζqªº±¹¬I¤§¤@¡C¥»¬ã¨sÆ[¹îHemisyncRÁn¹ï³Â¾KÂíÀR²`«×ªº¼vÅT¡C¦bª¾±¡¦P·N«á¡A§â¥þ³Â©Mªù¶E¯f¤H¤À¬°¤G²Õ¡A³B²z²Õµ¹¤©HemisyncRÁn(n = 31)¡A¹ï·Ó²Õµ¹ªÅ¥ÕºÏ±a(n = 29)¡C¨â²Õªº©ó¹w§¡¦b³N«e©M³N¤¤¡C²§¤þ×ô³Â¾K¬°¥D¡A°O¿ý»¤¾É¤Îºû«ù©Ò»Ý²§¤þ×ôªº¾¯¶q¡ABISºÊ´ú½T«O©Ò¦³¯f¤H³Â¾KÂíÀR¤@­P¡C§Ú­Ìµo²{¨â²Õ¶¡²§¤þ×ôªº»¤¾É(2.49 ¡Ó 0.59 mg/kg versus 2.60 ¡Ó 0.59 mg/kg; P = 0.48)¤Îºû«ù¾¯¶q(0.141 ¡Ó 0.02 mg ¡P kg^-1 ¡P min^-1 versus 0.146 ¡Ó 0.04 mg ¡P kg^-1 ¡P min^-1; P = 0.62)µL®t²§¡A¨â²Õ¯f¤HµJ¼{µ{«×µL®t²§¡Cµ²½×¡GHemisyncRÁn¤£¼vÅT¥þ³Â¯f¤HªºÂíÀR§@¥Î¡C

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Hemispheric synchronization is currently promoted as a treatment for preoperative anxiety and for reduction of intraoperative anesthetic and analgesic consumption. We designed this study to examine the effect of HemisyncR sounds on anesthetic hypnotic depth. After obtaining informed consent, we randomized subjects undergoing general anesthesia and outpatient surgery into two groups: the treatment group received HemisyncR sounds (n = 31), and the control group received a blank cassette tape (n = 29). Both groups received the intervention in the preoperative area and during the surgical procedure. Subjects underwent a propofol-based anesthetic regimen, and propofol doses required for the induction and maintenance of anesthesia were recorded. A bispectral index monitor was used to ensure that the hypnotic component of the anesthetic state was the same in all patients. We found no differences in the amount of propofol used during the induction of anesthesia (2.49 ¡Ó 0.59 mg/kg versus 2.60 ¡Ó 0.59 mg/kg; P = 0.48) or the maintenance of anesthesia (0.141 ¡Ó 0.02 mg ¡P kg^-1 ¡P min^-1 versus 0.146 ¡Ó 0.04 mg ¡P kg^-1 ¡P min^-1; P = 0.62) between the HemisyncR and control groups. We also found no differences between the HemisyncR group and the control group for participants with high state anxiety (P = not significant). We conclude that HemisyncR sounds do not reduce the hypnotic component of the anesthetic state of patients undergoing general anesthesia and surgery.

Departments of Neurology, Anesthesiology, and Rehabilitation Medicine, University of Wisconsin Medical School, University of Wisconsin, Madison

Anesth Analg 2003 97: 785-790.

A practical definition of neuropathic pain based on the distinction between neuropathic and inflammatory pain mechanisms is suggested. Neuropathic pain is in this case is defined as pain occurring in an area of the body affected by neurological disease. In addition to pain, the patient is likely to have weakness and numbness at the same time.

*Department of Medical Research, Chi-Mei Medical Center, Tainan, Taiwan; Department of Research and Education, National Defense Medical Center, Taipei, Taiwan; and Department of Anesthesiology, Tri-Service General Hospital, Taipei, Taiwan

Anesth Analg 2003 97: 806-809.

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A long-acting analgesic is particularly desirable in patients with long-lasting pain. In this study, we evaluated the antinociceptive effect and duration of action of three nalbuphine esters¡Xnalbuphine propionate, enanthate, and decanoate¡Xand observed whether these esters had a long-acting effect. Male Sprague-Dawley rats (n = 12 in each group) were used. Two studies were performed. In Study 1, we evaluated the antinociceptive effect of IM nalbuphine HCl with dosages of 0.25, 1.25, 2.5, 25, and 250 £gmol/kg. In Study 2, we evaluated the antinociceptive effects of IM nalbuphine base and esters with a dosage of 25 £gmol/kg. After 2.5, 25, and 250 £gmol/kg IM injections, we found that nalbuphine HCl produced a dose-related antinociceptive effect with durations of action of 1.5, 2, and 4 h, respectively. After a 25 £gmol/kg IM injection, the durations of action of the nalbuphine esters, nalbuphine propionate, enanthate, and decanoate were 5, 30, and 60 h, respectively. We conclude that, on an equimolar basis, nalbuphine esters produce relatively longer durations of action than nalbuphine HCl.

*Department of Anesthesiology and Research Institute, Rabin Medical Center, Golda-Hasharon Campus, affiliated with the Sackler School of Medicine, Tel-Aviv University; Department of Anesthesiology, Schneider Children¡¦s Medical Center, Petah Tiqva; and Department of Psychology, Hebrew University, Jerusalem, Israel

Anesth Analg 2003 97: 822-827

Surgery is associated with immune alterations, which are the combined result of tissue damage, anesthesia, postoperative pain, and psychological stress. In the present study, we compared the effects of several postoperative pain management techniques on postoperative immune function. Patients hospitalized for abdominal surgery were randomly assigned to one of three postoperative pain management techniques: opiates on demand (intermittent opiate regimen [IOR]), patient-controlled analgesia (PCA), and patient-controlled epidural analgesia (PCEA). Postoperative pain was assessed. Blood samples were collected before and 24, 48, and 72 h after surgery. Production of interleukin (IL)-1s, IL-2, and IL-6, natural killer cell cytotoxicity, and lymphocyte mitogenic responses were assessed. Patients of the PCEA group exhibited lower pain scores in the first 24 h after surgery compared with patients of the IOR and PCA groups. Mitogenic responses were suppressed in all groups in the first 24 h, returned to preoperative values by 72 h in the PCEA group, but remained suppressed in the PCA group. Production of IL-1s and IL-6 increased in the IOR and PCA groups, whereas it remained almost unchanged in the PCEA group. Patients receiving an epidural mixture of opiate and local anesthetics (PCEA group) exhibited reduced suppression of lymphocyte proliferation and attenuated proinflammatory cytokine response in the postoperative period.

*Surgical Intensive Care Unit, Biostatistical Unit, and Surgical Unit, Hopital Pontchaillou, Rennes, France

Anesth Analg 2003 97: 843-847.

In a randomized, double-blinded study, we evaluated the analgesic effect of ketamine in the management of pain in a surgical intensive care unit after major abdominal surgery. Patients received morphine patient-controlled analgesia with either placebo (Group M) or ketamine (Group K). Morphine was administered with initial loading doses of 2 mg until the visual analog scale (VAS) score was <30 and thereafter with bolus doses of 1 mg and a lockout time of 7 min. Ketamine was administered with an initial bolus of 0.5 mg/kg followed by a perfusion of 2 £gg ¡P kg^-1 ¡P min^-1 during the first 24 h and 1 £gg ¡P kg^-1 ¡P min^-1 during the following 24 h. The 4-h cumulative morphine doses were measured over 48 h. The VAS scores at rest and at The mobilization were measured every 4 h during 48 h. A total of 101 patients were enrolled, and 93 were analyzed (41 in Group K and 52 in Group M). VAS scores at rest and at mobilization were similar. cumulative consumption of morphine was significantly smaller in Group K (P < 0.05). We concluded that small doses of ketamine were a valuable adjunct to opioids in surgical intensive care unit patients after major abdominal surgery.

Division of Anesthesiology, Pain Management, Emergency and Critical Care Medicine, University Hospital, Nimes, France

Anesth Analg 2003 97: 867-872.

In this prospective cohort study, we compared the incidence and severity of spinal anesthesia (SA)-associated hypotension in severely preeclamptic (n = 30) versus healthy (n = 30) parturients undergoing cesarean delivery. After the administration of IV fluids, SA was performed with hyperbaric 0.5% bupivacaine, sufentanil, and morphine. Blood pressure (BP) was recorded before and at 2-min intervals for 30 min after SA. Clinically significant hypotension was defined as the need for ephedrine (systolic BP decrease to <100 mm Hg in healthy parturients or 30% decrease in mean BP in both groups). Despite receiving a smaller fluid volume (1653 ¡Ó 331 mL versus 1895 ¡Ó 150 mL; P = 0.005) and a larger bupivacaine dose (10.5 ¡Ó 0.9 mg versus 10.0 ¡Ó 0.7 mg; P = 0.019), the severely preeclamptic patients had a less frequent incidence of clinically significant hypotension (16.6% versus 53.3%; P = 0.006), which was less severe and required less ephedrine. The risk of hypotension was almost six times less in severely preeclamptic patients (odds ratio, 0.17; 95% confidence interval, 0.05¡V0.58; P = 0.006) than that in healthy patients.

Department of Anesthesiology and General Intensive Care, University of Vienna, Vienna, Austria

Anesth Analg 2003 97: 888-892.

Levobupivacaine is the isolated S(-)-stereoisomer of racemic bupivacaine. Important pharmacodynamic properties of levobupivacaine have not been determined for the femoral three-in-one block. In this randomized, controlled, double-blinded trial, we studied 60 ASA physical status I¡VIII patients scheduled for surgery of the lower limb. A nerve-stimulator-guided three-in-one block was performed as supplemental analgesic therapy with 20 mL of bupivacaine 0.5% (n = 20), levobupivacaine 0.5% (n = 20), or levobupivacaine 0.25% (n = 20). Sensory onset time, quality of blockade, and duration of blockade were assessed by pinprick test in the central sensory innervation region of the femoral nerve (distribution of the anterior femoral cutaneous nerve). A rating scale from 100% (normal sensation) to 0% (no sensation at all) as compared with the contralateral leg was used. No significant difference in sensory onset time among the three local anesthetic solutions was observed (mean [95% confidence interval]): bupivacaine 0.5%, 27 min (20¡V33 min); levobupivacaine 0.5%, 24 min (18¡V30 min); and levobupivacaine 0.25%, 30 min (23¡V36 min) (P = 0.49). The analgesic quality of the blockade was also not significantly different among the three groups, whereas a complete sensory block was achieved in significantly fewer patients in the levobupivacaine 0.25% group (P = 0.02). The duration of blockade was significantly shorter with levobupivacaine 0.25% compared with the other groups: bupivacaine 0.5%, 1053 min (802¡V1304 min); levobupivacaine 0.5%, 1001 min (844¡V1158 min); and levobupivacaine 0.25%, 707 min (551¡V863 min) (P = 0.01). Levobupivacaine 0.5% is recommended instead of bupivacaine 0.5% for the three-in-one block.

Madhav Swaminathan, MD, Barbara G. Phillips-Bute, PhD, and Joseph P. Mathew, MD

Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina

Anesth Analg 2003;97:642-647

Left ventricular ejection time (LVET) is an important component in evaluating left ventricular performance. This measurement is usually made by measuring the timing of the transaortic valve flow velocity by continuous-wave Doppler. Although M-mode has also been used for measuring LVET, it has not been compared with the Doppler method. We tested the hypothesis that the M-mode-measured duration of aortic valve opening is comparable to Doppler-derived measurement of LVET by transesophageal echocardiography (TEE). Measurements were made in 31 patients undergoing nonaortic valve cardiac surgery. The timing of transaortic flow by continuous-wave Doppler was compared with the M-mode-derived timing of aortic valve opening. There was close correlation (Pearson correlation coefficient, r = 0.86; P < 0.0001) between M-mode and Doppler measurements. There was no significant difference between the two techniques by linearity tests (P > 0.1). Bland-Altman analysis showed no significant bias. We confirmed the hypothesis that M-mode-derived measurement of LVET is comparable to Doppler-derived measurement of LVET. M-mode may be an acceptable alternative to the Doppler method, especially when transvalvular velocity gradients cannot be readily obtained. M-mode is a simple, yet often underused, method of evaluating LVET during TEE.

Yoshikazu Ikeda, MD^*, Kiyonobu Nishikawa, MD^*, Kenji Ohashi, MD, Takashi Mori, MD^*, and Akira Asada, MD^*

*Department of Anesthesiology and Intensive Care Medicine, Osaka City University Medical School, Osaka, Japan; and Department of Anesthesia, Hoshigaoka Kosei-nenkin Hospital, Osaka, Japan

Anesth Analg 2003;97:748-754

Epidural administration of clonidine induces hypotension and bradycardia secondary to decreased sympathetic nerve activity. In this study, we sought to elucidate the change in baroreflex response caused by epidural clonidine. Thirty-six cats were allocated to six groups (n = 6 each) and were given either thoracic epidural clonidine 4 £gg/kg or lidocaine 2 mg/kg during 0.5, 1.0, or 1.5 minimum alveolar anesthetic concentration (MAC) isoflurane anesthesia. Heart rate (HR), mean arterial blood pressure (MAP), and cardiac sympathetic nerve activity (CSNA) were measured. Depressor and pressor responses were induced by IV nitroprusside 10 £gg/kg and phenylephrine 10 £gg/kg, respectively. Baroreflex was evaluated by the change in both CSNA and HR relative to the peak change in MAP (CSNA/MAP and HR/MAP, respectively). These measurements were performed before and 30 min after epidural drug administration. Epidural clonidine and lidocaine decreased HR, MAP, and CSNA by similar extents. CSNA/MAP and HR/MAP for depressor response were suppressed with epidural lidocaine and clonidine in all groups but the clonidine 0.5 MAC isoflurane group (0.197 ¡Ó 0.053 to 0.063 ¡Ó 0.014 and 0.717 ¡Ó 0.156 to 0.177 ¡Ó 0.038, respectively, by epidural lidocaine [P < 0.05] but 0.221 ¡Ó 0.028 to 0.164 ¡Ó 0.041 and 0.721 ¡Ó 0.177 to 0.945 ¡Ó 0.239, respectively, by epidural clonidine during 0.5 MAC isoflurane). Those for pressor response were suppressed in all groups. We conclude that thoracic epidural clonidine suppresses baroreflex gain during isoflurane anesthesia >1.0 MAC but may offer certain advantages compared with epidural lidocaine during 0.5 MAC isoflurane by virtue of preserving baroreflex sensitivity when inadvertent hypotension occurs.

Mohamed Naguib, MB BCh, MSc, FFARCSI, MD^*, Max T. Baker, PhD^*, Gilberto Spadoni, PhD, and Marc Gregerson, BS^*

Departments of Anesthesia, *University of Iowa College of Medicine, Iowa City, Iowa; and Institute of Medicinal Chemistry and Toxicology, University of Urbino, piazza Rinascimento, Italy

Anesth Analg 2003;97:763-768

2-Bromomelatonin is an analog of melatonin with a higher melatonin receptor affinity. We tested the hypnotic and analgesic properties of 2-bromomelatonin and compared them with those of propofol. Sprague-Dawley rats were assigned to receive 2-bromomelatonin or propofol IV, or morphine intraperitoneally. Righting reflex and response to tail clamping were assessed. Both 2-bromomelatonin and propofol caused a dose-dependent increase in the percent of rats displaying loss of both the righting reflex and the response to tail clamping. 2-Bromomelatonin was comparable to propofol in terms of its rapid onset and short duration of hypnosis. The 50% effective dose (95% confidence interval) for loss of righting reflex for propofol and 2-bromomelatonin were 3.7 (3.4¡V4.0) and 38 (35¡V41) mg/kg, respectively. Corresponding values for loss of response to tail clamp were 2.9 (3.5¡V4.0) and 21 (15¡V30) mg/kg, respectively. 2-Bromomelatonin is approximately 6¡V10 times less potent than propofol depending on the end-point used. Intraperitoneal 30 mg/kg morphine did not affect the righting reflex, but resulted in loss of response to tail clamping in all animals. 2-Bromomelatonin can exert hypnotic and antinocifensive effects similar to that observed with propofol. Unlike propofol, the reduced nocifensive behavior persisted after the animals had regained their righting reflex. This study provides evidence that 2-bromomelatonin has properties that are desirable in anesthetics or anesthetic adjuvants.

Tadahiko Ishiyama, MD PhD, Takeshi Oguchi, MD PhD, Tetsuya Iijima, MD, Takashi Matsukawa, MD PhD, Satoshi Kashimoto, MD PhD, and Teruo Kumazawa, MD PhD

Department of Anesthesiology, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan

Anesth Analg 2003;97:780-784
¦b½Æ¦X¥þ³Â©Mµw½¤¥~³Â¾K¹Lµ{¤¤¡A³q±`À³¥Î³Â¶À¯À©M·sºÖªL¨Ó³B²z¯f¤Hªº§C¦åÀ£¡A¨âºØÃĪ«¥i¯à·|§ïÅܳ¾K²`«×¡C¦b¥Ø«eªº¬ã¨s¤¤¡A§Ú­Ì¤ñ¸û¤F³Â¶À¯À©M·sºÖªL¹ï½Æ¦X¥þ³Â©Mµw½¤¥~³Â¾K¯f¤H¸£¹qÂùÀW«ü¡]BIS¡^ªº¼vÅT¡C¦b³q¹Lµw½¤¥~¾ÉºÞµ¹¤©¯f¤H¥¬¤ñ¥d¦]«á¡AÀ³¥Î²§¤þ×ô©Mºû®w·ÍÓi¶i¦æ³Â¾K»¤¾É¡A¨Ã±Ä¥Î0.75%¤C¬tîų¾Kºû«ù¡C®ðºÞ´¡ºÞ«á¬ù10¤ÀÄÁ¡A´ú©w¯f¤HªºBIS§@¬°°ò¦­È¡C¦b³Â¾K¹Lµ{¤¤¿ï¾Ü¸û³Â¾K«e°Ê¯ß¦åÀ£¤U­°30%ªº¯f¤H§@¬°¹ï·Ó²Õ¡]n=9¡^¡C¹ï©ó¦åÀ£¤U­°¸û©úÅã¦Ó¤£±o¤£À³¥ÎÃĪ«³B²zªº¯f¤HÀH¾÷¤À¬°¨â²Õ¡A¤@²Õµ¹¤©0.1mg/Kg³Â¶À¯À³B²z¡]n=17¡^¡A¥t¥~¤@²Õµ¹¤©2£gg/Kg·sºÖªL³B²z¡]n=17¡^¡C¦b10¤ÀÄÁ¤º¨C¶¡¹j1¤ÀÄÁ´ú©wBIS­È¡Cµ²ªGµo²{³Â¶À¯À²Õ¯f¤H¦b²Ä7¨ì10¤ÀÄÁ¤ºBIS©úÅã¤j©ó¹ï·Ó²Õ©M·sºÖªL²Õ¡]P¡Õ0.05¡×¦Ó¥B³Â¶À¯À²Õ¦³7­Ó¯f¤HªºBIS¤j©ó60¡A¦ý¦b¹ï·Ó²Õ©M·sºÖªL²Õ§¡¨S¦³¯f¤HBIS¤j©ó60¡]P¡Õ0.005¡×¡C¦]¦¹¦b½Æ¦X¥þ³Â©Mµw½¤¥~³Â¾K¹Lµ{¤¤³Â¶À¯À¯à¼W¥[¤F±wªÌªºBIS¡A¦Ó·sºÖªL«h¤£¯à¡C

Ephedrine and phenylephrine are used to treat hypotension during combined general and epidural anesthesia, and they may change anesthetic depth. In the current study, we evaluated the effects of ephedrine versus phenylephrine on bispectral index (BIS) during combined general and epidural anesthesia. After injection of ropivacaine through the epidural catheter, general anesthesia was induced with propofol and vecuronium, and was maintained with 0.75% sevoflurane. Approximately 10 min after the intubation, BIS was recorded as a baseline value. Patients with decreases in arterial blood pressure <30% of the preanesthetic values were defined as control group (n = 9). Patients who had to be treated for larger decreases in arterial blood pressure were randomly assigned to receive ephedrine 0.1 mg/kg (n = 17) or phenylephrine 2 £gg/kg (n = 17). BIS values were recorded at 1-min intervals for 10 min. BIS in the ephedrine group was significantly larger from 7 to 10 min than that in the control and phenylephrine groups (P < 0.05). Seven patients in the ephedrine group had BIS >60, whereas no patient in the control and phenylephrine groups had BIS >60 (P < 0.005). Ephedrine, but not phenylephrine, increased BIS during general anesthesia combined with epidural anesthesia.

L. Winter, R. Nadeson, A. P. Tucker, and C. S. Goodchild

Monash University Department of Anaesthesia, Monash Medical Centre, Clayton, Victoria, Australia

Anesth Analg 2003;97:798-805
¥»¬ã¨s¤¤¡A§Ú­Ì¬ã¨s¤F³æ¿Wµ¹¤©¶Ü°ØÃþÃĪ«ªâ¤Ó¥§¡A¶Ü°Ø©M®ñ¥i଩M¦X¨Öµ¹¤©¨âºØ¯«¸gÃþ©T¾JÃþÃĪ«¡Gªüªk¨FÀs©Mªüªk¦hÀs¹ïÂíµh©MÂíÀR§@¥Îªº¼vÅT¡C±N¶Ü°ØÃþÃĪ«©M¯«¸gÃþ©T¾JÃþÃĪ«¤À§Oª`®g¤JWistar¶¯¹«ªº¸¡µÄ¤º¡A¥Hopen-field¬¡°ÊºÊ´ú©Mrotarod»ö¾¹¨Ó§PÂ_ÂíÀR®ÄªG¡C¦b¥¼¹FÂíÀR¾¯¶q«e¡Aµe¥XÂíµh§@¥Îªº¾¯¶q-¤ÏÀ³¦±½u¡C¦b«DÂíÀR¾¯¶q¤U¡Aªâ¤Ó¥§¡B¶Ü°Ø©M®ñ¥iଧ¡¥i²£¥Í¾¯¶q¨Ì¿à©Êªº·n§À¤ÏÀ³¡]tail flick latency,TFL¡^¡C¥Ñ©ó¨âºØ¯«¸gÃþ©T¾JÃħ¡¤£¯à§ïÅÜTFL¡A©Ò¥H³q¹L¹q¬y±j«×¨Ó§PÂ_«DÂíÀR¾¯¶q¤U³o¨âºØÃĹïÂíµh§@¥Îªº¼vÅT¡C¦b¹q¬y´ú¸Õ¤¤¡Aªüªk¦hÀs¥i²£¥Í©úÅ㪺Âíµh§@¥Î¡A¦Óªüªk¨FÀs«hµL¦¹§@¥Î¡C¾¨ºÞ³æ¿W¥Îªüªk¦hÀs¤£¼vÅTTFL¡A¦ý»P¤TºØÂíµhÃĦX¥Î«á§¡¥i¨ÏTFLªº¾¯¶q-¤ÏÀ³¦±½u¥ª²¾¡Cªüªk¨FÀs³æ¿W¥ÎÃÄ©M¦X¨Ö¶Ü°ØÃþÃĪ««h§¡µL¼vÅT¡C»P¶Ü°ØÃþÃĪ«¦X¥Î®É¡A¨âºØÃħ¡µLÂíÀR§@¥Î¡C§Ú­Ì±o¥Xµ²½×¡G»P¶Ü°Ø¡Bªâ¤Ó¥§©M®ñ¥iଦX¥Î®É¡Aªüªk¦hÀs¥i¼W±jÂíµh§@¥Î¦Ó¤£¥[²`ÂíÀR§@¥Î¡A¦Óªüªk¨FÀsµL¦¹§@¥Î¡C

In this study, we investigated the antinociceptive and sedative effects of the opioids fentanyl, morphine, and oxycodone given alone and in combination with two neurosteroids: alphadolone and alphaxalone. An open-field activity monitor and rotarod apparatus were used to define the sedative effects caused by opioid and neurosteroid compounds given alone intraperitoneally to male Wistar rats. Dose-response curves for antinociception were constructed using only nonsedative doses of these drugs. At nonsedating doses, fentanyl, morphine, and oxycodone all caused dose-dependent tail flick latency (TFL) antinociceptive effects. Because neither neurosteroid altered TFL, electrical current was used as the test to determine doses of neurosteroid that caused antinociceptive effects at nonsedative doses. Alphadolone 10 mg/kg intraperitoneally caused significant antinociceptive effects in the electrical test but alphaxalone did not. All three opioid dose-response curves for TFL antinociception were shifted to the left by coadministration of alphadolone even though alphadolone alone had no effect on TFL. Alphaxalone given alone had no antinociceptive effects at nonsedative doses and it had no effect on opioid antinociception. Neither neurosteroid caused sedative effects when combined with opioids. We conclude that coadministration of alphadolone, but not alphaxalone, with morphine, fentanyl, or oxycodone potentiates antinociception and that this effect is not caused by an increase in sedation.

Xavier Culebras, MD^*, Jean-Baptiste Corpataux, MD, Giovanni Gaggero, MD, and Martin R. Tramer, MD DPhil^*

*Division d¡¦Anesthesie, Departement APSIC (Anestheie, Pharmacologie et Soins Intensif de Chirurgie), Hopitaux Universitaires de Geneve, Geneve, Switzerland; Service d¡¦Anesthesie, Hopital de La Chaux-de-Fonds, La Chaux-de-Fonds, Switzerland; and Service d¡¦Anesthesie, Hopital Sud Fribourgeois, Riaz, Switzerland

Anesth Analg 2003;97:816-821

The antiemetic dose response of droperidol when it is added to patient-controlled analgesia with morphine is not well known. We randomly allocated adults who received postoperative morphine patient-controlled analgesia (1-mg bolus, 5-min lockout) to one of four regimens: no droperidol (control) or 5, 15, or 50 £gg of droperidol per milligram of morphine. Efficacy and adverse effects were recorded during 24 h and were analyzed with number needed to treat (NNT) and number needed to harm with 95% confidence intervals. Data from 82 controls, 82 patients receiving droperidol 5 £gg, 82 receiving droperidol 15 £gg, and 83 receiving droperidol 50 £gg were analyzed. Average consumption of droperidol per 24 h was 0.2 mg with the 5-£gg regimen, 0.61 mg with the 15-£gg regimen, and 2.04 mg with the 50-£gg regimen. In controls, the incidence of nausea was 48.8%; with droperidol 5 £gg, it was 42.7% (NNT compared with control, 16 [95% confidence interval, 4.7 to -11]); with 15 £gg, it was 32.9% (NNT, 6.3 [3.3¡V100]); and with 50 £gg, it was 21.7% (NNT, 3.7 [2.4 to 7.6]). In controls, the incidence of vomiting was 24.4%; with droperidol 5 £gg, it was 23.2% (NNT compared with control, 82 [7 to -8.5]); with 15 £gg, it was 22.0% (NNT, 41 [6.5 to -9.6]); and with 50 £gg, it was 12% (NNT, 8.1 [4.2¡V142]). In controls, the incidence of pruritus was 12.2%; with droperidol 5 £gg, it was 6.1% (NNT compared with control, 16 [6.7 to -37]); and with 15 and 50 £gg, it was 2.4% (NNT, 10 [5.7¡V52]). In controls, the incidence of sedation was 2.4%; with droperidol 5 £gg, it was 8.5% (number needed to harm (NNH) compared with control, 16 [7.7 to -123]); with 15 £gg, it was 6.1% (NNH, 27 [10 to -40]); and with 50 £gg, it was 18.1% (NNH, 6.4 [4.1¡V15]). There were no extrapyramidal symptoms and no cardiac adverse events. There was no difference in patient satisfaction. The optimal antiemetic dose of droperidol is 15¡V50 £gg/mg of morphine. Larger doses may have more antivomiting efficacy but are likely to be unacceptably sedating.

Claudia Coimbra, MSc MD, FRCPC^*, Manon Choiniere, PhD, and Thomas M. Hemmerling, MD DEAA^*

Department of *Anesthesiology and Burn Centre, Hotel-Dieu, Centre Hospitalier de l¡¦Universite de Montreal (CHUM), Universite de Montreal, Quebec, Canada

Anesth Analg 2003;97:839-842

he first change of dressings after skin grafting in burn patients is a source of great anxiety because of pain anticipation and the immediate and first confrontation with the result of skin grafting. We designed this dose-finding study to determine the feasibility and safety of patient-controlled sedation (PCS) using propofol during these procedures. Twenty patients were familiarized with the PCS and asked to use PCS whenever they felt uncomfortable or anxious. Analgesia was provided by a single bolus of morphine IV 15 min before the procedure according to their daily intake. The first 10 patients used a fixed bolus of propofol 0.3 mg/kg and a lockout of 5 min. The degree of sedation was measured using bispectral index (BIS) monitoring. Demands versus delivery of propofol boluses were recorded. Within 1 h after the procedure, pain intensity was evaluated and satisfaction scores obtained from patients and nurses performing the dressing changes. In the first 10 patients, there were no respiratory rates <10 breaths/min, systolic and diastolic blood pressure were within 25% of baseline values, and peripheral saturation stayed more than 94% with additional small flow oxygen via nasal insufflation. There were double the demands than actual deliveries of propofol boluses. The BIS did not show significant decreases of <80 in any patient reflecting an insufficient state of sedation. Because the interim analysis of the efficacy of the PCS setup showed an insufficient state of sedation, a different PCS setup was evaluated in a second group of 10 patients (an individualized propofol bolus, titrated to achieve a significant decrease of BIS or a sleepy state, and no lockout period). The second group of patients showed a more effective sedation, with respiratory and hemodynamic variables being not significantly different from the first group of patients. PCS with propofol is feasible in burn patients and can be used safely. To provide an optimal sedation, we suggest to initially titrate the bolus to achieve a significant decrease of BIS or a clinically effective state of sedation and to abolish the lockout interval.

Kamatham A. Naidu, PhD^*, Eugene S. Fu, MD, E. Truitt Sutton, PhD, Leon D. Prockop, MD^*, and Alan Cantor, PhD

Departments of *Neurology, Anesthesiology, and Physiology, College of Medicine, University of South Florida, Tampa, Florida; and Oncology Program, H. Lee Moffitt Cancer Center, University of South Florida, Tampa, Florida

Anesth Analg 2003;97:857-862

The pathophysiology of ischemia/reperfusion injury involves extravascular migration of leukocytes from the bloodstream to the site of injury. Leukocyte adhesion and intercellular adhesion molecule-1 (ICAM-1) play an important role in the recruitment of leukocytes to the site of injury. In this study, we evaluated the role of the ICAM-1 in spinal cord ischemia and the therapeutic effects of epidural ICAM-1 monoclonal antibody (Mab). The descending aorta was occluded below the renal artery with an aneurysm clip in rabbits anesthetized with halothane. The following variables were evaluated, in addition to ICAM-1 expression in the lumbar spinal cord, in animals receiving saline or ICAM-1 Mab via the epidural route: (1) leukocyte recruitment in the lumen of capillary vessels of the lumbar spinal cord (L6-7) at 8 h after 30 min of aortic occlusion and (2) neurological evaluation at 20 h after aortic occlusion of 10, 15, 17.5, 20, or 25 min. Paraplegia was graded with the following scale: Grade 0, no deficit; Grade 1, partial deficit; and Grade 2, complete paraplegia. Spinal cord ischemia increased the expression of ICAM-1 in the endothelium of spinal cord capillaries and led to capillary leukocyte recruitment and extravascular migration into the lumbar spinal cord parenchyma, which was ablated with epidural ICAM-1 Mab. Epidural ICAM-1 Mab reduced neurological deficits and offered neuroprotection. These findings demonstrate the involvement of the ICAM-1 pathway in spinal cord ischemia and the neuroprotective effects of epidural ICAM-1 Mab. Strategies to ameliorate spinal cord ischemia may entail the administration of leukocyte antiadhesion molecules into the neuraxial space.

Lena S. Sun, MD^*,, Shin Takuma, MD, Rui Lui, MD, and Shunichi Homma, MD

Departments of *Anesthesiology, Pediatrics, and Medicine, College of Physicians and Surgeons of Columbia University, New York, New York

Anesth Analg 2003;97:878-882
¹ï©ó¤HÃþ¨Ó»¡¡A­L¨à¼ÉÅS©ó¤U»P¨ä¤ß¦åºÞ¥\¯à²§±`¦³Ãö¡C§Ú­Ì¶i¦æ¤F¤@¶µ¹êÅç¡A§Y¿ï¾Ü¤F¤@¸s§³®Wªº¤j¥Õ¹«¡A¦b¾ã­Ó§³®W´Á¤Î¤À®Y«áªº14¤Ñ³q¹L­GÄé¬~¥Í²zÆQ¤ô©Î60mg/kgªº¥i¥d¦]¡C§Ú­ÌµM«á¥Î°ªÀW²v¸g¯Ý¶WÁn¤ß°Ê¹ÏÀˬd7¤Ñ©M14¤Ñªº·s¥Í¥Õ¹«¥H½T©w¦b¼ÉÅS¥i¥d¦]¤U¬O§_¼vÅT¨ä¤ßŦ¦¬ÁY¥\¯à¡C©Ò¦³ªº¬ã¨s³£¦b¨S¦³ÂíÀR¥B²M¿ôª¬ºA¤U¡C§Ú­Ì±q¤Gºû¹Ï¹³¤¤­pºâ¨ÅÀY¤¤¦Ù¤ô¥­Åܤƪº­±¿n¨Ó±oª¾¦¬ÁY¥\¯à©M¤ß²v¡]HR¡^¡C¨â²Õ¦~ÄÖ¬qªº¥i¥d¦]¼ÉÅS²Õ¡AÀR®§ª¬ºA¤Uªº¤ß²v³£§Ö©ó¹ï·Ó²Õ¡A¦ý°ò¦¤ßŦ¦¬ÁY¥\¯à¹ï·Ó²Õ©M¼ÉÅS²ÕµL®t²§¡C¥u¦b¨Ï¥Î³Ì¤j¾¯¶q¦h¤Ú×ô¤BÓi¤U¯à¨Ï©Ò¦³²Õªº¥Õ¹«¤ß²v¼W§Ö¡]¥X¥Í7¤Ñªº¹ï·Ó²Õ¤ß²v¥Ñ438¡Ó3bpm¼W§Ö¦Ü462¡Ó10bpm¡F¥X¥Í7¤Ñªº¥i¥d¦]²Õ¤ß²v¥Ñ466¡Ó3bpm¼W§Ö¦Ü493¡Ó7bpm¡F¥X¥Í14¤Ñªº¹ï·Ó²Õ¤ß²v¥Ñ443¡Ó4bpm¼W§Ö¦Ü487¡Ó4bpm¡F¥X¥Í14¤Ñªº¥i¥d¦]²Õ¤ß²v¥Ñ477¡Ó4bpm¼W§Ö¦Ü501¡Ó5bpm¡^¡C¦h¤Ú×ô¤BÓi¯à¨Ï¥X¥Í7¤Ñ¡]±q76.6%¡Ó0.6%¨ì81.5%¡Ó0.7%¡^©M14¤Ñ¡]±q78.2%¡Ó0.7%¨ì81.9%¡Ó0.7%¡^ªº¹ï·Ó²Õ¥Õ¹«¤ßŦ¦¬ÁYÅãµÛ¼W±j¡A¦ý¹ï©ó¥i¥d¦]²Õ¤£©úÅã¡]¥X¥Í7¤Ñªº±q76.7%¡Ó0.8%¨ì78.9%¡Ó0.8%¦Ó¥X¥Í14¤Ñªº±q76.8%¡Ó1.1%¨ì79.3%¡Ó0.8%¡^¡CµÇ¤W¸¢¯À¹ï¥X¥Í7¤Ñªº¹ï·Ó²Õ¦³©úÅ㪺¤ßŦ¦¬ÁY§@¥Î¡A¦ý¹ï¥i¥d¦]²Õ¤£©úÅã¡A¦Ó¹ï¥X¥Í14¤Ñªº¹ï·Ó²Õ©M¥i¥d¦]²Õ³£µL©úÅ㪺ÅܤơC§Ú­Ìªº¬ã¨sµ²ªG´£¥Ü³ò²£´Á¼ÉÅS©ó¥i¥d¦]¤£·|¨ÏÀR®§¤ß¥\¯à¦³©ÒÅܤơA¦ý¥i«d®z·s¥Í¥Õ¹«¹ï£]µÇ¤W¸¢¯À¨üÅé¿E°Ê¾¯ªº¤ÏÀ³¡C³o¨Çµ²ªGªí©ú³ò²£´Á¼ÉÅS©ó¥i¥d¦]²Õ¥i­°§C·s¥Í¨à¦­´Á¹ï¼vÅT¤ß¦Ù¦¬ÁY¤OÃĪ«ªº¤ÏÀ³¡C

Fetal cocaine exposure has been associated with a variety of cardiovascular dysfunctions in humans. We treated pregnant rats with either saline or cocaine at 60 mg/kg by gastric lavage for the entire gestational period and for 14 days after parturition. We then performed high-frequency transthoracic echocardiography to determine whether cocaine exposure affected neonatal cardiac contractile function in vivo in 7- and 14-day-old neonatal rats. All studies were performed in the unsedated, conscious state. Heart rate (HR) and systolic function, expressed as fractional area of change at the midpapillary muscle level, were calculated from two-dimensional images. Resting HR was faster in the cocaine-exposed group at both ages, but baseline contractile function was not different between control (CTL) and cocaine-exposed (COC) neonatal rats. Dobutamine induced a significant increase in HR in all groups at only the largest dose tested (Day 7 CTL HR increased from 438 ¡Ó 3 bpm to 462 ¡Ó 10 bpm; Day 7 COC HR increased from 466 ¡Ó 3 bpm to 493 ¡Ó 7 bpm; Day 14 CTL HR increased from 443 ¡Ó 4 bpm to 487 ¡Ó 4 bpm; Day 14 COC HR increased from 477 ¡Ó 4 bpm to 501 ¡Ó 5 bpm). Dobutamine elicited a significant increase in contractile response at both Day 7 (from 76.6% ¡Ó 0.6% to 81.5% ¡Ó 0.7%) and Day 14 in CTL (from 78.2% ¡Ó 0.7% to 81.9% ¡Ó 0.7%), but not in COC, animals (from 76.7% ¡Ó 0.8% to 78.9% ¡Ó 0.8% at Day 7 and from 76.8% ¡Ó 1.1% to 79.3% ¡Ó 0.8% at Day 14). Epinephrine induced a significant increase in contractile response in CTL, but not in COC, rats at Day 7 and had no effect on fractional area of change at 14 days of age in either CTL or COC animals. Our results indicate that perinatal cocaine exposure does not modify resting contractile function but attenuates the contractile response to ß-adrenoceptor stimulation in the neonatal rat. These results suggest that perinatal cocaine exposure may lead to decreased responsiveness to inotropic drugs during the early neonatal period.

Duminda N. Wijeysundera, MD*, and W. Scott Beattie, MD PhD, FRCPC

From the *Department of Anesthesia, University of Toronto, and the Department of Anesthesia, University Health Network, University of Toronto, Toronto, ON

Anesth Analg 2003;97:634-641

Cardiac complications are the leading cause of death after noncardiac surgery. Despite theoretical benefits, calcium channel blockers (CCB) are not widely used in the perioperative setting. This systematic review assessed the efficacy of CCBs during noncardiac surgery. MEDLINE, EMBASE, Science Citation Index, PubMed, and reference lists were searched without language restriction for randomized controlled trials (RCT) evaluating CCBs during noncardiac surgery. Two reviewers independently abstracted data on death, myocardial infarction (MI), ischemia, supraventricular tachyarrhythmia (SVT), and congestive heart failure (CHF). Treatment effects were calculated as relative risks (RR) with 95% confidence intervals (CI). Eleven studies (1007 patients) were included. CCBs significantly reduced ischemia (RR, 0.49; 95% CI, 0.30¡V0.80; P = 0.004) and SVT (RR, 0.52; 95% CI, 0.37¡V0.72; P < 0.0001). CCBs were associated with trends towards reduced death and MI. In post hoc analyses, CCBs significantly reduced death/MI (RR, 0.35; 95% CI, 0.15¡V0.86; P = 0.02) and major morbid events (MME), defined as death, MI, or CHF (RR, 0.39; 95% CI, 0.17¡V0.89; P = 0.02). In subgroup analyses, diltiazem significantly reduced ischemia, SVT, death/MI, and MMEs. This meta-analysis shows CCBs significantly reduced ischemia, SVT, and combined end-points in the setting of noncardiac surgery. The majority of these benefits are attributable to diltiazem, suggesting the need for further evaluation of this drug in a large RCT.

Christophe Dadure, MD, Philippe Pirat, MD, Olivier Raux, MD, Rachel Troncin, MD, Alain Rochette, MD, Christine Ricard, MD, and Xavier Capdevila, MD PhD

Department of Anesthesia and Critical Care Medicine, Lapeyronie University Hospital, Montpellier, France

Anesth Analg 2003 97: 687-690

Continuous peripheral nerve blocks (CPNB) after pediatric major orthopedic surgery are not widely used. We conducted a prospective descriptive study to evaluate the effectiveness of disposable elastomeric pumps for CPNB in children. After inducing general anesthesia, 25 consecutive children scheduled for major orthopedic surgery received a 0.5-mL/kg bolus of a mixture of 1% lidocaine with epinephrine and 0.25% bupivacaine in axillary, femoral, or popliteal catheters. After surgery, disposable pumps with 0.2% ropivacaine were connected. Pump flows were adjusted to the patient¡¦s weight. Postoperative pain was evaluated using a visual analog scale or Children and Infants Postoperative Pain Scale scores at H1, H6, H12, H24, and H48, as well as amounts of rescue analgesia, adverse events, and motor and sensory block. An ambulation score for the children was also evaluated. Eleven popliteal, nine femoral, and five axillary continuous blocks were performed. All the blocks were effective for surgery. The mean total dose consumption of 0.2% ropivacaine was 10.1 mg/kg. Disposable pump flow varied from -9.61% to +8.6% compared with the theoretical one. Postoperative analgesia was excellent. The median of pain score was zero at each period studied. Sensory and motor block were noted at H1 and decreased from the sixth hour. No adverse events were noted. We concluded that the use of elastomeric disposable pumps for CPNB in children was an effective technique

Emma E. Johnson, BSc(Hons)*, Helen Gibson, BSc(Hons)*, Beverley Nicol, PhD, Johannes Zanzinger, PhD, Peter Widdowson, PhD, Mark Hawthorn, PhD, Geza Toth, PhD, Judit Farkas, PhD, Remo Guerrini, PhD, and David G. Lambert, PhD*

*University Department of Anaesthesia, Critical Care and Pain Management, Leicester Royal Infirmary, Leicester, United Kingdom; Veterinary Medicine Research & Development, Pfizer Ltd., Sandwich, Kent, United Kingdom; Isotope Laboratory, Institute of Biochemistry, Biological Research Centre, Szeged, Hungary; and Department of Pharmaceutical Sciences and Biotechnology Centre, University of Ferrara, Ferrara, Italy

Anesth Analg 2003 97: 741-747

Nociceptin/orphanin FQ (N/OFQ) is the endogenous ligand for the N/OFQ receptor (NOP), whose characteristics in the dog are unknown. We therefore compared [3H]N/OFQ binding in dog and rat brain membranes. Radioligand saturation/competition studies with these membranes and leucyl-[3H]N/OFQ(1¡V17)OH or the novel radioligand [3H]N/OFQ(1¡V13)NH2 were performed to determine receptor density and ligand affinity. The density of classic opioid receptors was determined by using [3H]diprenorphine. Leucyl-[3H]N/OFQ(1¡V17)OH binding was concentration dependent and saturable in dog (maximum binding capacity [Bmax], 28.7 ¡Ó 2.8 fmol/mg of protein; equilibrium dissociation constant as negative log [pKd], 10.27 ¡Ó 0.11) and rat (Bmax, 137.0 ¡Ó 12.9 fmol/mg of protein; pKd, 10.41 ¡Ó 0.05). In comparison, the Bmax and pKd of [3H]diprenorphine were, respectively, 77.7 ¡Ó 5.3 fmol/mg of protein and 9.74 ¡Ó 0.09 in dog and 79.1 ¡Ó 18.2 fmol/mg of protein and 9.51 ¡Ó 0.04 in rat. In dog, [3H]N/OFQ(1¡V13)NH2 binding to NOP receptors was also saturable (Bmax, 23.7 ¡Ó 2.0 fmol/mg of protein; pKd, 10.16 ¡Ó 0.12). In both species, leucyl-[3H]N/OFQ(1¡V17)OH was displaced by various NOP ligands. Dynorphin A, N/OFQ(1¡V5)NH2, and nocistatin were essentially inactive. There was a significant positive correlation (r2 = 0.95; P < 0.0001) between pKi values (an estimate of affinity) obtained in displacement studies in rat and dog. We have demonstrated a low density of NOP receptors, measured with two radioligands, in dog, and these receptors display a high degree of pharmacological similarity with those natively expressed in the rat.

Katsumi Okuyama, MD^*, Takashi Matsukawa, MD^*, Makoto Ozaki, MD, Daniel I. Sessler, MD, Tomoki Nishiyama, MD, Makoto Imamura, MD^*, and Teruo Kumazawa, MD^*

Departments of Anesthesia, *University of Yamanashi, Faculty of Medicine, Yamanashi; Tokyo Women¡¦s Medical University, and Tokyo University School of Medicine, Tokyo, Japan; and Outcomes Research^TM Institute and Departments of Anesthesiology, University of Louisville, Louisville, Kentucky

Anesth Analg 2003 97: 759-762.

Dopamine is a thermoregulatory neurotransmitter that provokes hypothermia when injected in or near the hypothalamus. Doxapram stimulates release of dopamine from carotid bodies, but is known to have central effects that are probably, at least in part, similarly mediated. We thus tested the hypothesis that doxapram produces a substantial, dose-dependent reduction in the shivering threshold in rabbits. Twenty-four rabbits, anesthetized with isoflurane, were randomly assigned to 1) saline (control), 2) 0.25 mg ¡P kg^-1 ¡P h^-1 doxapram, or 3) 0.50 mg ¡P kg^-1 ¡P h^-1 doxapram. These doses are within the recommended range for humans. Body temperature was reduced at a rate of 2¢X to 3¢XC/h by perfusing water at 10¢XC through a U-shaped thermode positioned in the colon. Core temperatures were recorded from the distal esophagus. A blinded observer evaluated shivering. Core temperature at the onset of shivering defined the threshold. Data were analyzed with a one-way analysis of variance; P < 0.05 was considered statistically significant. Hemodynamic and respiratory responses were comparable in the groups. The control rabbits shivered at 36.3¢X ¡Ó 0.3¢XC, those given 0.25 mg ¡P kg^-1 ¡P h^-1 doxapram shivered at 34.8¢X ¡Ó 0.5¢XC, and those given 0.50 mg ¡P kg^-1 ¡P h^-1 shivered at 33.7¢X ¡Ó 0.6¢XC. All the shivering thresholds significantly (P < 0.001) differed from one another. The magnitude of this inhibition, if similar in humans, would be clinically important.

Department of Anesthesiology, Nagasaki University School of Medicine, Nagasaki, Japan

Anesth Analg 2003 97: 776-779.

We performed this study to assess the accuracy of transcutaneous CO₂ (PTCCO₂) monitoring compared with end-tidal CO₂ (PETCO₂) in thoracic anesthesia. Twenty-six patients undergoing pneumonectomy with thoracotomy for which a long period of one-lung ventilation (OLV) was required were studied. The lungs were mechanically ventilated in the lateral decubitus position. PTCCO₂, PETCO₂, and arterial CO₂ (PaCO₂) were simultaneously measured during two-lung ventilation (TLV) and during OLV at intervals of 15 min. All patients completed the study protocol. Bland-Altman analysis revealed a bias of -0.4 mm Hg with a precision of ¡Ó2.5 mm Hg during OLV and 1.4 mm Hg with ¡Ó4.3 mm Hg during TLV when PTCCO₂ and PaCO₂ were compared and revealed a bias of -5.8 mm Hg with a precision of ¡Ó4.1 mm Hg during OLV and -7.1 mm Hg with ¡Ó4.6 mm Hg during TLV when PETCO₂ and PaCO₂ were compared. We conclude that PTCCO₂ monitoring is accurate for evaluating CO₂ levels during thoracic anesthesia.

Anesth Analg 2003 97: 791-797

Chronic pain is a subjective experience and has not only physical, but also psychological and social dimensions. In the present study, we sought to determine whether an effective pain reduction would improve mood, behavioral, and cognitive outcome measures in chronic pain patients. Four-hundred-seventy-seven patients entering pain therapy at our university pain center were prospectively studied during the first year of treatment. Patients received pharmacotherapy, acupuncture, transcutaneous nerve stimulation, physiotherapy, and invasive pain treatment. Intensity and quality of pain were assessed with the Visual Analog Scale and Multidimensional Pain Scale. Psychological and social aspects were evaluated using the Pain Behavior Questionnaire and the Profile of Mood States questionnaire. Significant reductions in pain intensity (Visual Analog Scale, 7.35 at pretreatment and 1.03 after 12 mo; P = 0.01; Multidimensional Pain Scale, F = 6.185; P < 0.001) were accompanied by improvements in behavioral and cognitive dimensions (Pain Behavior Questionnaire, F = 9.483; P = 0.002). However, mood and psychological well-being did not improve (Profile of Mood States, F = 0.416; P = 0.551). The authors conclude that reducing pain intensity improves behavioral and cognitive dimensions but not psychological well-being and cognitive assessment.

Department of Anesthesiology and Center for the Study of Pharmacologic Plasticity in the Presence of Pain, Wake Forest University School of Medicine, Winston-Salem, North Carolina

Anesth Analg 2003 97: 810-815.

Opioids administered during surgery may be beneficial by preempting postoperative pain or detrimental by causing acute tolerance. We used a stable model of hyperalgesia in volunteers to test whether acute opioid exposure also results in such pain sensitization over a period of hours in humans. Ten healthy volunteers were studied. Areas of mechanical hyperalgesia and allodynia were induced by topical capsaicin application plus intermittent heating. Computer-controlled IV remifentanil infusion was titrated to a targeted plasma concentration that reduced pain report to noxious heat by 70% and was maintained at this level for 60¡V100 min. Areas of hyperalgesia and allodynia were measured during and after remifentanil infusion. Remifentanil (targeted concentration of 3.1 ¡Ó 1.2 ng/mL) reduced areas of hyperalgesia and allodynia by 33% ¡Ó 31% and 65% ¡Ó 28%, respectively, during infusion (P < 0.05). Areas of hyperalgesia and allodynia continuously enlarged 4 h after remifentanil was stopped, to 180% ¡Ó 47% and 180% ¡Ó 86%, respectively. This study demonstrates that acute opioid exposure enhances hypersensitivity for hours after exposure. If applicable to the surgical setting, this could increase the dose of opioid required for postoperative analgesia and enhance, rather than inhibit, postoperative pain.

*Department of Internal Medicine B, Bnai-Zion Medical Center and Pain Relief Unit, Rambam Medical Center, and the Haifa Pain Research Group, the Technion, Israel Institute of Technology, Haifa, Israel

Anesth Analg 2003 97: 828-832.

Quantitative Sensory Testing (QST) is a psycho-physiological test used to identify dysfunction of individual nerve fiber types. In the present study, we investigated whether selective nerve fiber dysfunction, as assessed by QST, correlates with the effectiveness of epidural steroid injections (ESI) in patients with lumbar radiculopathy. Twenty patients with unilateral painful sciatica caused by disc herniation participated in this open study. Before ESI, quantitative thermal and mechanical sensory testing was conducted at the most painful dermatome and the contralateral dermatome. The primary outcome measure used was the self-recording of pain intensity twice daily with a 0¡V10 numerical pain scale (NPS). Secondary efficacy measures included the Short Form of the McGill Pain Questionnaire, the straight leg raising test, and the lumbar range of motion. A significant difference in all types of sensory thresholds between the affected and the contralateral dermatomes was detected at baseline. All outcome measures improved subsequent to the ESI. A significant positive correlation was found between the increase in cold sensation thresholds of the affected dermatome (A-fiber dysfunction) and the improvement in NPS. The increase in touch and vibration thresholds (As-fiber dysfunction) was found to be inversely correlated with the improvement in NPS. No correlation was found between heat sensation thresholds (C fibers) and any of the outcome measures. These results suggest that QST has the potential to be an important tool in the selection of the appropriate treatment (e.g., ESI versus surgery) for patients with sciatica and may assist in identifying the mechanisms of pain generation in these patients.

Andrew D. McLeod, FRCA*, Farrell Igielman, FRCA*, Clare Elwell, PhD, Mark Cope, PhD, and Martin Smith, FRCA*

Departments of *Neuroanaesthesia and Medical Physics & Bioengineering, The National Hospital for Neurology and Neurosurgery, University College London Hospitals & Centre for Anaesthesia, UCL, London, United Kingdom

Anesth Analg 2003 97: 851-856.

Measuring Cerebral Oxygenation DWe measured simultaneous changes in jugular venous oxygen saturation, brain tissue oxygen tension, and cerebral tissue oxygen index by using near-infrared spectroscopy during normobaric hyperoxygenation in eight severely brain-injured patients. Patients were ventilated at their baseline fraction of inspired oxygen (FIO2), followed by stepped changes in FIO2 to 1.0, 0.6, and 0.02¡V0.05 less than baseline. There was an increase (P < 0.01) in jugular venous saturation (mean ¡Ó SD) from a baseline value of 79% ¡Ó 7% to 89% ¡Ó 6% and 84% ¡Ó 8% at an FIO2 of 1.0 and 0.6, respectively. The changes in brain tissue oxygen tension were from a baseline of 30 ¡Ó 5 mm Hg to 147 ¡Ó 36 mm Hg and 63 ¡Ó 6 mm Hg at an FIO2 of 1.0 and 0.6, respectively (P < 0.01). The baseline tissue oxygen index was 78% ¡Ó 3%, and this increased to 83% ¡Ó 5% and 80% ¡Ó 4% at an FIO2 of 1.0 and 0.6, respectively. There was a reduction (P < 0.05) in tissue oxygen index to 76.2% ¡Ó 3.0% when the FIO2 was reduced to less than baseline. The changes in the three variables followed similar patterns but varied in their degree and speed of response. During brain injury, FIO2 affects measured variables of cerebral oxygenation.

Wendy H. L. Teoh, MBBS, and Alex T. H. Sia, MMed

Department of Anesthesia, KK Women¡¦s & Children¡¦s Hospital, Singapore

Anesth Analg 2003 97: 873-877

We investigated the effect of sequential administration of intrathecal (IT) hyperbaric bupivacaine (after the initial administration of IT hypobaric fentanyl) on the duration of spinal analgesia. Thirty-seven nulliparous parturients with a cervical dilation 5 cm were randomized to receive either IT fentanyl 25 £gg and plain bupivacaine 2.5 mg (group P; n = 19) or IT fentanyl 25 £gg and hyperbaric (with 8% glucose) bupivacaine 2.5 mg (group H; n = 18). The two components of the IT injectate were administered sequentially (fentanyl 25 £gg diluted in 2 mL of normal saline, immediately followed by 0.5 mL of 0.5% bupivacaine). Patients were then positioned with their torso elevated at 30¢X for 30 min. Pain scores using 0¡V100 visual analog scales were collected before combined spinal/epidural analgesia and at 5, 15, and 30 min after the block. Patients in Group H had a longer median duration of analgesia (122 min; range, 80¡V210 min) than Group P (95 min; range, 75¡V125 min) (P < 0.01). Group H also had a more limited dermatomal spread (median highest sensory level of T8 versus T4 in group P; P < 0.05). The side-effect profile was similar. Under these circumstances, hyperbaric bupivacaine conferred an increased duration of IT analgesia compared with plain bupivacaine.

Shigeo Ohmura, MD, Akiko Sugano, MD, Masayuki Kawada, MD, and Ken Yamamoto, MD

Department of Anesthesiology and Intensive Care Medicine, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan

Anesth Analg 2003 97: 893-897.

Local anesthetic toxicity produced by an inadvertent IV injection is attenuated by the pulmonary uptake of local anesthetics. We compared the pulmonary uptake of ropivacaine and levobupivacaine after a bolus injection in rabbits. Sixteen anesthetized rabbits were randomly assigned to either a ropivacaine group or a levobupivacaine group. A bolus containing ropivacaine or levobupivacaine 0.5 mg/kg and indocyanine green (an intravascular indicator) 0.25 mg/kg was injected rapidly into the vena cava. Arterial blood samples were collected serially at 1.2-s intervals for 30 s. Concentrations of local anesthetic and indocyanine green in each sample were determined for the calculation of first-pass uptake of a local anesthetic in the lung. The first-pass uptake of levobupivacaine (31.4% ¡Ó 8.3%; mean ¡Ó SD) was larger than that of ropivacaine (22.9% ¡Ó 5.6%), and the maximum arterial concentration of ropivacaine (21.2 ¡Ó 2.8 £gg/mL) was larger than that of levobupivacaine (18.6 ¡Ó 1.9 £gg/mL). We conclude that the pulmonary uptake of levobupivacaine is larger than that of ropivacaine after a bolus injection. Therefore, the advantages of ropivacaine over levobupivacaine in terms of less cardiovascular toxicity may be offset by the smaller pulmonary uptake after an inadvertent IV injection.

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