Retraction notice to "Recoveries of post-tetanic twitch and train-of-four responses after administration of vecuronium with different inhalation anaesthetics and neuroleptanaesthesia" [Br J Anaesth 1993; 70: 402-404]

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief of British Journal of Anaesthesia. The study is retracted for the following reasons: Statistical analysis suggests that the data may be fabricated. Y Saitoh provided a statement in a personal communication to a member of the editorial board of British Journal of Anaesthesia that the study was not approved by the Institutional Review Board and that no evidence exists to support the study findings. Additionally, the Japanese Society of Anesthesiologists has recommended retraction of this article: http://www.anesth.or.jp/english/pdf/news20170925.pdf.

Retraction notice to "Relationship between post-tetanic twitch and single twitch response after administration of vecuronium" [Br J Anaesth 1993; 71: 443-444]

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief of British Journal of Anaesthesia. The study is retracted for the following reasons: Y Saitoh provided a statement in a personal communication to a member of the editorial board of British Journal of Anaesthesia that the study was not approved by the Institutional Review Board and that no evidence exists to support the study findings.

Retraction notice to "Post-tetanic count and single twitch height at the onset of reflex movement after administration of vecuronium under different types of anaesthesia" [Br J Anaesth 1994; 72: 688-690]

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief of British Journal of Anaesthesia. The study is retracted for the following reasons: Y Saitoh provided a statement in a personal communication to a member of the editorial board of British Journal of Anaesthesia that the study was not approved by the Institutional Review Board and that no evidence exists to support the study findings.

Changes in respiratory physiological dead space and compliance during non-abdominal, upper abdominal and lower abdominal surgery under general anaesthesia

BACKGROUND AND OBJECTIVE

To evaluate the temporal changes in respiratory physiological dead space and dynamic compliance of the respiratory system during non-abdominal, upper abdominal and lower abdominal surgery under general anaesthesia with intermittent positive pressure ventilation.

METHODS

Thirty-four adult patients were studied (non-abdominal surgery, n = 8; upper abdominal surgery, n = 13 and lower abdominal surgery in lithotomy position, n = 13). Physiological dead space was measured using the single breath carbon dioxide test. The physiological dead space to tidal volume ratio (VD/VT), dynamic compliance of respiratory system, expiratory tidal volume and respiratory rate were measured 10 min after tracheal intubation, and 30, 60 and 120 min later.

RESULTS

In lower abdominal surgery group, VD/VT was significantly increased at 120 min compared with 0 min (P = 0.005) and 30 min (P = 0.009). There were no significant differences in VD/VT between the three groups at any time point. Compliance decreased significantly in patients with upper abdominal (120 min) and lower abdominal surgery (60 and 120 min), but there were no significant changes during non-abdominal surgery.

CONCLUSIONS

We found that the VD/VT increased in patients undergoing lower abdominal surgery in lithotomy and head down tilt, and compliance decreased in those undergoing upper abdominal and lower abdominal surgery over time.

Chromatographic determination of free lidocaine and its active metabolites in plasma from patients under epidural anesthesia

OBJECTIVE

We developed a simple and selective assay method for simultaneous determination of free lidocaine (LDC) and its active metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX) in plasma, by using high-performance liquid chromatography (HPLC). The method was applied to the plasma concentration monitoring in continuous epidural anesthesia with LDC.

MATERIALS AND METHODS

Free fraction was separated from plasma by using an ultrafiltration technique. Free and total LDC, MEGX and GX in plasma were analyzed by HPLC equipped with ordinary octadecylsilyl silica (ODS) column and ultraviolet (UV) detector.

PATIENTS

Five male patients with cancer who received epidural injection of 1.5% LDC for 5 hours in elective thoracic surgery, were enrolled to determine the plasma levels of total and free LDC, MEGX and GX.

RESULTS AND DISCUSSION

The calibration curve for free LDC, MEGX and GX were linear at the concentration of 25 to 1,000 ng ml(-1) (r = 0.9998 - 0.9999). The recoveries for LDC, MEGX and GX from plasma water were ranged 73.2-89.1%. The coefficient variations for intra- and inter-day assay for LDC, MEGX and GX were less than 4.1%. The detection limit ofeach drug was 20 ng ml(-1). Plasma-free MEGX after 180 min epidural injection was higher than free LDC, even though the total concentration of MEGX was 4 times lower than that of LDC. The percentages of free fraction for LDC, MEGX and GX were 11.7, 48.5 and 78.3% after 5-hour epidural administration of LDC. Since the free fraction of MEGX and GX increases and exceeds the concentration of free LDC during continuous epidural anesthesia, accumulation of these toxic metabolites should be carefully monitored as well as LDC.

CONCLUSION

The present method is a reliable technique and can be applied to monitoring free LDC, MEGX and GX, which provide us beneficial information as to the LDC metabolism and toxicity.

Comparative effects of xenon and nitrous oxide on diaphragmatic contractility in dogs

BACKGROUND

Xenon at two different concentrations (30%, 60%) has no effect on diaphragmatic contractility. This study was undertaken to compare the effects of xenon and nitrous oxide (N2O), a commonly used and well-established gas anesthetic, on diaphragmatic contractility in dogs.

METHODS

Twenty-one pentobarbitone-anesthetized dogs were randomly divided into three groups of seven each: group 1 received xenon 30% (0.25 MAC) in oxygen; group 2 received N2O 47% (0.25 MAC) in oxygen; and group 3 received N2O 60% (0.32 MAC) in oxygen. Diaphragmatic contractility was assessed by transdiaphragmatic pressure (Pdi) at low- (20-Hz) and high-frequency (100-Hz) stimulation, after maintaining 60 min of stable condition. The integrated electrical activity of diaphragm (Edi) to each stimulus was measured.

RESULTS

With an inhalation of xenon 30%, N2O 47%, or N2O 60%, Pdi and Edi at both stimuli did not change. No difference in Pdi or Edi was observed among the groups.

CONCLUSION

When used at clinical concentration, xenon or N2O does not affect contractility and electrical activity of the diaphragm in dogs.

Inhaled olprinone improves contractility of fatigued canine diaphragm

BACKGROUND

Diaphragmatic fatigue is implicated as a cause of respiratory failure. This study was undertaken to evaluate the effects of inhaled olprinone, a newly developed phosphodiesterase III inhibitor, on the contractility of fatigued diaphragm in dogs.

METHODS

Diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz stimulation applied for 30 min. When fatigue was established, group I (n=8) received inhaled vehicle; group II (n=8) received inhaled olprinone 1 mg; group III (n=8) received inhaled olprinone 2 mg. Diaphragmatic contractility was assessed by transdiaphragmatic pressure (Pdi, cm H2O).

RESULTS

In the presence of fatigue, in each group, Pdi at low-frequency (20 Hz) stimulation decreased from baseline values (P<0.05), whereas Pdi at high-frequency (100 Hz) stimulation did not change. In groups II and III, during olprinone administration, Pdi at both stimuli increased from fatigued values (20 Hz stimulation: group II (mean (SD)) 10.8 (1.0) to 12.5 (1.3), group III 10.9 (1.7) to 15.0 (3.0); 100 Hz stimulation: group II 20.1 (1.9) to 22.6 (1.3), group III 20.6 (2.0) to 24.5 (2.0), P<0.05). The increase in Pdi was larger in group III than in group II (P<0.05).

CONCLUSIONS

Inhaled olprinone produces a dose-dependent improvement in contractility of fatigued canine diaphragm.

The dose-range effects of propofol on the contractility of fatigued diaphragm in dogs

Diaphragmatic fatigue may contribute to the development of respiratory failure. We studied the dose-range effects of propofol on the contractility of fatigued diaphragm in dogs. Animals 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. Immediately after the end of a fatigue-producing period, Group 1 received no study drug; Group 2 was infused with small-dose propofol (0.1 mg/kg initial dose plus 1.5 mg x kg(-1) x h(-1) maintenance dose); Group 3 was infused with large-dose propofol (0.1 mg/kg initial dose plus 6.0 mg x kg(-1) x h(-1) maintenance dose). We assessed diaphragmatic contractility by transdiaphragmatic pressure (Pdi). After the fatigue-producing period, in each group, Pdi at low-frequency (20-Hz) stimulation decreased from baseline values (P < 0.05), whereas there was no change in Pdi at high-frequency (100-Hz) stimulation. In Groups 2 and 3, with an infusion of propofol, Pdi at 20-Hz stimulation decreased from fatigued values (P < 0.05). Compared with Group 1, Pdi at 20-Hz stimulation decreased from fatigued values (P < 0.05) during propofol administration in Groups 2 and 3. The decrease in Pdi was more in Group 3 than in Group 2 (P < 0.05). We conclude that propofol decreases the contractility of fatigued canine diaphragm in a dose-related fashion.

IMPLICATIONS

Propofol is a widely used IV anesthetic for the induction and maintenance of general anesthesia and sedation. It decreases, in a dose-related fashion, the contractility of fatigued diaphragm in dogs.

Effect of intravenous prostaglandin E1 on pial vessel diameters and intracranial pressure in rabbits

BACKGROUND

The main advantages of prostaglandin E1 (PGE1) for induced hypotension during neurosurgery include a rapid onset of action, a quick recovery from hypotension, lack of toxicity, maintenance of adequate perfusion to vital organs, and maintenance of cerebral blood flow reactivity to carbon dioxide during hypotension. However, there is no report that shows the effect of PGE1 on cerebral microvessel diameter and only a few data are available that show the effect of PGE1 on intracranial pressure. The aim of this study was to measure cerebral arteriole and venule diameters and intracranial pressure (ICP) during PGE1-induced hypotension to evaluate whether PGE1 is suitable for neuroanesthesia.

METHODS

We measured the effects of 0.1, 0.3, 1.0, 3.0, and 10.0 microg x kg(-1) x min(-1) of intravenous PGE1 on mean arterial pressure (MAP), cerebral arteriole and venule diameters and ICP in anesthetized rabbits.

RESULTS

MAP decreased statistically significantly from baseline at the infusion rates of 1.0, 3.0, and 10.0 microg x kg(-1) x ml(-1). Arteriole diameter increased significantly from the baseline at the infusion rate of 10.0 microg x kg(-1) x ml(-1) (18% from control). Venule diameter did not change from baseline value at any infusion rate. ICP did not change from baseline value at any infusion rate.

CONCLUSION

We conclude that PGE1 might be a suitable drug for induced hypotension in neurosurgery from the viewpoint of its small effect on the cerebral microvessels and ICP.

Plasma lidocaine concentrations during continuous thoracic epidural anesthesia after clonidine premedication in children

There is no report concerning oral clonidine's effects on epidural lidocaine in children. Therefore, we performed a study to assess the concentrations of plasma lidocaine and its major metabolite (monoethylglycinexylidide [MEGX]) in children receiving continuous thoracic epidural anesthesia after oral clonidine premedication. Ten pediatric patients, aged 1-9 yr, were randomly allocated to the Control or Clonidine 4 microg/kg group (n = 5 each). Anesthesia was induced and maintained with sevoflurane in oxygen and air (FIO2 40%). Epidural puncture and tubing were carefully performed at the Th11-12 intervertebral space. An initial dose of 1% lidocaine (5 mg/kg) was injected through a catheter into the epidural space, followed by 2.5 mg x kg(-1) x h(-1). Plasma concentrations of lidocaine and MEGX were measured at 15 min, 30 min, and every 60 min for 4 h after the initiation of continuous epidural injection. The concentrations of lidocaine and MEGX were measured using high-pressure liquid chromatography with ultraviolet detection. Hemodynamic variables were similar between members of the Control and Clonidine groups during anesthesia. The Clonidine group showed significantly smaller lidocaine concentrations (p < 0.05) and the concentration of MEGX tended to be smaller in the plasma of the Clonidine group for the initial 4 h after the initiation of epidural infusion. In conclusion, oral clonidine preanesthetic medication at a dose of 4 microg/kg decreases plasma lidocaine concentration in children.

IMPLICATIONS

Oral clonidine decreases the plasma lidocaine concentration in children. Our finding may have clinical implications in patients receiving continuous epidural anesthesia. Additionally, perhaps an additional margin of safety regarding lidocaine toxicity is gained through the use of oral clonidine in children who will receive epidural lidocaine.

[Change of cross-sectional area of the right internal jugular vein: effect of Trendelenburg position and valsalva maneuver]

To compare the effect of Valsalva maneuver and 10 degrees Trendelenburg position on the right internal jugular vein (RIJV), we measured RIJV cross-sectional area using ultrasound imaging during these procedures. The study group consisted of 13 normal healthy volunteers (6 males, 7 females, aged 25-47) with no history of neck surgery or right internal jugular vein (RIJV) puncture. All ultrasound images were obtained at the level of the cricoid cartilage. The subjects were positioned supine, and the measurements were taken with the subjects supine, under Valsalva maneuver, and under 10 degrees Trendelenburg tilt position. The cross-sectional areas of the RIJV during Valsalva maneuver and 10 degrees Trendelenburg position compared to those with supine position were 314 +/- 162%, and 192 +/- 96%, respectively. We conclude that both procedures increase cross-sectional area of IRJV significantly and in this respect Valsalva maneuver is more effective than Trendelenburg position.

The formalin test: effects of formalin concentration and short-term halothane inhalation

BACKGROUND AND OBJECTIVES

In order to evaluate the effects of formalin concentration and inhalational anesthetics in formalin tests, we injected 5 concentrations of formalin into awake and anesthetized rats and investigated their behavior and the c-fos immunoreactivity of their spinal cords.

METHODS

Sixty adult male Sprague-Dawley rats were divided into 10 experimental groups. Each rat was either manually restrained or subdued through several minutes of 2% to 2.5% halothane inhalation, and then 1 of 5 concentrations of 0%, 5%, 10%, 27%, or 100% formalin (0%, 1.85%, 3.7%, 10%, or 37% formaldehyde solutions) was injected into its rear paw. Nociceptive behaviors were checked for 1 hour, 6 times for each 5-minute period. Two hours after the formalin injections, the rats were killed and c-fos immunoreactivity was measured.

RESULTS

Typical responses were observed in the 5% and 10% formalin (1.85% and 3.7% formaldehyde) groups, and nociceptive behaviors were lower in the 27% and 100% formalin (10% and 37% formaldehyde) groups. The number of c-fos-positive cells increased as the formalin concentration increased. Halothane inhalation affected the results of both the behavior and the c-fos immunoreactivity, especially in the 10% formalin (3.7% formaldehyde) group.

CONCLUSIONS

It is desirable to describe both formalin and formaldehyde concentrations simultaneously and to do formalin tests without inhalational anesthetics.

The residual effects of hemorrhagic shock on pain reaction and c-fos expression in rats

To investigate the residual effects of hemorrhagic shock on pain reaction and c-fos expression, we performed formalin tests after hemorrhage and reinfusion in rats. Twenty adult male Sprague-Dawley rats were divided into Control (n = 10) and Postshock (n = 10) groups. The mean blood pressure of the Control group was 100-120 mm Hg, and that of the Postshock group was kept at 50-60 mm Hg for 30 min by draining blood. After 15 min of returning mean blood pressure to normal levels in the Postshock group, 10% formalin (3.7% formaldehyde solution, 100 microL) was injected into the left rear paw of both groups. Nociceptive behaviors were observed for 1 h after the formalin injection. The rats were killed at 2 h after the formalin injection, and the lumbar spinal cord was then stained for c-fos immunohistochemistry by using the avidin-biotin-peroxidase method. Animals in the Postshock group showed considerably less nociceptive behavior than those in the Control group. C-fos expression in the deep layer (IV-VI) of the spinal cord was significantly less in the Postshock group. In conclusion, decreases of nociceptive behaviors and c-fos expression were observed under normotensive conditions after hemorrhagic shock. The mechanisms governing these reactions remain unclear.

IMPLICATIONS

Formalin tests were performed after hemorrhage and reinfusion in rats. A stress-induced analgesia was observed under normotensive conditions after hemorrhagic shock. The mechanisms remain unclear.

Midazolam versus propofol for reducing contractility of fatigued canine diaphragm

The effects of midazolam and propofol on the contractility of fatigued canine diaphragm were examined. Diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz applied for 30 min. After fatigue had been induced, group I (n=10) received no study drug, group II (n=10) was given a propofol infusion (0.1 mg kg(-1) loading dose plus 1.5 mg kg(-1) h(-1) maintenance dose) and group III (n=10) was given a midazolam infusion (0.1 mg kg(-1) loading dose plus 0.1 mg kg(-1) h(-1) maintenance dose). Diaphragmatic contractility was assessed by measuring transdiaphragmatic pressure (Pdi). After the fatigue-inducing period in each group, Pdi at low-frequency (20 Hz) stimulation was lower than the baseline values (P<0.05), whereas no change in Pdi at high-frequency (100 Hz) stimulation was observed. In group II, Pdi at 20 Hz stimulation was lower than fatigued values (P<0.05); Pdi at 100 Hz stimulation did not change. In group III, Pdi at both stimulation frequencies was lower than fatigued values (P<0.05). Compared with group I, Pdi at 20 Hz stimulation was lower than fatigued values (P<0.05) during administration of the study drug in groups II and III. The decrease in Pdi was greater in group III than in group II (P<0.05). In conclusion, midazolam compared with propofol is associated with an inhibitory effect on contractility in the fatigued canine diaphragm.

Dose-Response Characteristics of Midazolam for Reducing Diaphragmatic Contractility

A sedative dose of midazolam decreases contractility of the diaphragm, but no data are available concerning the relationship between dose and diaphragmatic contractility. We studied the dose-response characteristics of midazolam for reducing the diaphragmatic contractility in dogs. Animals were divided into three groups of eight each: Group 1 received no study drug, Group 2 was infused with a sedative dose of midazolam (0.1 mg/kg initial dose plus 0.1 mg x kg(-1) x h(-1) maintenance dose), and Group 3 was infused with an anesthetic dose of midazolam (0.1 mg/kg initial dose plus 0.5 mg x kg(-1) x h(-1) maintenance dose). We assessed the diaphragmatic contractility by transdiaphragmatic pressure (Pdi). With an infusion of midazolam in Groups 2 and 3, Pdi at low-frequency (20 Hz) and high-frequency (100 Hz) stimulation decreased from the baseline values (P < 0.05), and the integrated electrical activity of diaphragm (Edi) at 100-Hz stimulation decreased from the baseline values, whereas Edi at 20-Hz stimulation did not change. Compared with Group 1, Pdi and Edi for each stimulus decreased during midazolam infusion in Groups 2 and 3 (P < 0.05). The decrease in Pdi and Edi was more in Group 3 than in Group 2 (P < 0.05). We conclude that midazolam decreases, in a dose-dependent manner, contractility of the diaphragm in dogs.

Repeated administration of protamine does not attenuate circulatory changes caused by protamine reversal of heparin in dogs

OBJECTIVE

To determine whether repeated administration of protamine attenuates circulatory changes caused by protamine reversal of heparin and to evaluate the significance of nitric oxide generation.

DESIGN

Prospective, randomized, controlled, animal study.

SETTING

University research laboratory.

PARTICIPANTS

Twenty-seven adult mongrel dogs.

INTERVENTIONS

The animals were randomly assigned to 3 groups (n = 9 in each) according to the pretreatment. The control group was pretreated with normal saline, and the 2 other groups were given 2 different doses of protamine: protamine 0.1 (protamine, 0.1 mg/kg) and protamine 1.0 (protamine, 1.0 mg/kg). Under general anesthesia, all animals were anticoagulated with intravenous heparin, 200 IU/kg. Five minutes after heparin injection, preadministered saline (control) or protamine in saline was infused during 60 seconds. Five minutes after the pretreatment, protamine, 2.0 mg/kg in control, 1.9 mg/kg in protamine 0.1, or 1.0 mg/kg in protamine 1.0, was administered intravenously during 10 seconds.

MEASUREMENTS AND MAIN RESULTS

Percent changes in mean arterial blood pressure among the 3 groups at each period were not significantly different except 60 minutes after protamine infusion. Mean pulmonary arterial pressure in the protamine 1.0 group at 5, 15, 20, and 60 minutes was higher than in the control group. Serum nitrate concentration was not significantly different among the 3 groups at baseline and 10 minutes after protamine injection.

CONCLUSION

Repeated administration of protamine does not attenuate circulatory changes caused by protamine reversal of heparin in dogs. Nitric oxide generation does not appear to be responsible for the phenomenon.

The effects of 30% and 60% xenon inhalation on pial vessel diameter and intracranial pressure in rabbits

Xenon may increase cerebral blood flow and intracranial pressure (ICP). To evaluate the effects of xenon on brain circulation, we measured pial vessel diameter changes, CO(2) reactivity, and ICP during xenon inhalation in rabbits. Minimum alveolar anesthetic concentration (MAC) for xenon was established in rabbits (n = 6). By using a cranial window model, pial vessel diameters were measured at 30% and 60% xenon inhalation and in time control groups (n = 15). ICP, mean arterial blood pressure, and heart rate were recorded during 30% and 60% xenon inhalation (n = 5). Pial vessel diameters were measured during hypocapnia and hypercapnia conditions in 60% Xenon and Control groups (n = 14). MAC for xenon was 85%. Xenon (0.35 and 0.7 MAC) dilated the arterioles (10% and 18%, respectively) and venules (2% and 4%, respectively) (P < 0.05). Dilation of arterioles was more prominent than that of venules. ICP, mean arterial blood pressure, and heart rate did not change during xenon inhalation. No difference in CO(2) reactivity was observed between Xenon and Control groups (P = 0.79). Sixty percent xenon (0.7 MAC) dilated brain vessels, but venule changes were small. Xenon did not increase ICP and preserved CO(2) reactivity of the brain vessels.

IMPLICATIONS

Xenon might increase cerebral blood flow; however, 0.7 minimum alveolar anesthetic concentration xenon preserved both low intracranial pressure and CO(2) reactivity of the cerebral vessels in the normal rabbit.

[Pulmonary edema in a child following laryngospasm triggered by a laryngeal mask airway during emergence from anesthesia]

A 9-year-old boy underwent biopsy of the tumor at the external auditory meatus under general anesthesia with a laryngeal mask airway(LMA). During emergence from anesthesia, laryngospasm with marked inspiratory effort and cyanosis occurred. The LMA was removed and the patient was orotracheally intubated following vecuronium administration. In spite of controlled ventilation with 100% oxygen, oxygen saturation remained at low 90s and pink frothy sputum appeared in the tracheal tube. We suspected negative pressure pulmonary edema and treated him with mechanical ventilation with positive end-expiratory pressure. Seventeen hours later the pink frothy sputum decreased and he was extubated. Laryngospasm during emergence from anesthesia with an LMA can induce negative pressure pulmonary edema, especially in pediatric patients.

Effects of i.v. metoclopramide, atropine and their combination on gastric insufflation in children anaesthetized with sevoflurane and nitrous oxide

METHODS

To determine effects of i.v. metoclopramide, atropine and their combination on the airway pressures at which gastric insufflation occurs in children, 45 healthy infants and children (ASA I) received an inhalational induction of anaesthesia with sevoflurane, N2O and O2. A blinded observer used a stethoscope to auscultate over the upper abdomen for any air entry. First, proximal airway pressure was slowly increased by closing the pop-off valve of the anaesthesia machine until gas was heard entering the stomach (pop-off point, control measurement). If the peak inspiratory pressure reached 40 cm H2O, the patient was to be excluded from the study. Then, all subjects randomly received i.v. atropine 0.01 mg.kg-1, metoclopramide 0.2 mg.kg-1, or atropine 0.01 mg.kg-1 plus metoclopramide 0.2 mg.kg-1 (n=15 each), and determination of the pop-off point was repeated 5 min later. The stomach was evacuated before each measurement.

RESULTS

Atropine significantly decreased the pop-off point [from 21 +/- 3 to 19 +/- 2 cm H2O (mean +/- SD), P < 0.05], while metoclopramide significantly increased the pop-off point (from 20 +/- 3 to 26 +/- 6 cm H2O, P < 0.05). The combination of metoclopramide and atropine did not alter the pop-off point (from 20 +/- 2 to 19 +/- 5 cm H2O).

CONCLUSION

Since metoclopramide exerts only mild effect on the pop-off point, cricoid pressure still remains the standard anaesthetic practice to prevent gastric insufflation in children. Prophylactic i.v. metoclopramide may be restricted to, and its clinical usefulness should be determined in, symptomatic patients with gastro-oesophageal reflux.

[Dose-response study of preincisional buprenorphine on emergence time and postoperative analgesic requirement in patients anesthetized with sevoflurane]

The effect of intravenous buprenorphine on emergence time from sevoflurane anesthesia and postoperative analgesic requirement was evaluated after otolaryngeal surgeries. Forty-five patients were randomly assigned to one of three treatment groups (n = 15 each): Control-group received saline as a control; 2 micrograms-group received buprenorphine 2 micrograms.kg-1; and 4 micrograms-group received buprenorphine 4 micrograms.kg-1, respectively. Study drug was administered intravenously at the induction of general anesthesia. Anesthesia was maintained with sevoflurane (1.5%) and nitrous oxide (66%) in oxygen. The pain score, postoperative analgesic requirement, and incidence of nausea and/or vomiting were examined. The emergence times were 16.4 +/- 3.5, 14.7 +/- 5.2, and 17.8 +/- 7.7 min [mean +/- SD], in the control-group, the 2 micrograms-group, and the 4 micrograms-group, respectively. There were no differences among the groups in term of the end-tidal sevoflurane concentration immediately before tracheal extubation. In the control-group, the 2 micrograms-group, and the 4 micrograms-group, 10, 1, and 3 patients, requested additional analgesics during the first 24 hours after surgery, respectively (control-group vs. 2 micrograms-group and 4 micrograms-group, P < 0.05). Nausea and vomiting occurred more frequently in the 2 micrograms-group and the 4 micrograms-group. We conclude that buprenorphine (2 or 4 micrograms.kg-1) reduced analgesic requirement during the first 24 hours after surgery without delaying emergence from sevoflurane anesthesia.

Colforsin daropate improves contractility in fatigued canine diaphragm

We studied the effects of colforsin daropate, a water-soluble forskoline derivative, on contractility in fatigued canine diaphragm. Dogs were randomly divided into 4 groups of 8 each. In each group, diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz applied for 30 min. Immediately after the end of a fatigue-producing period, Group 1 received no study drug, Group 2 was infused with small-dose colforsin daropate (0.2 microg. kg(-1). min(-1)), Group 3 was infused with large-dose colforsin daropate (0.5 microg. kg(-1). min(-1)), and Group 4 was infused with nicardipne (5 microg. kg(-1). min(-1)) during colforsin daropate (0.5 microg. kg(-1). min(-1)) administration. After the fatigue-producing period, in each group transdiaphragmatic pressure (Pdi) at low-frequency (20-Hz) stimulation decreased from baseline values (P < 0.05), whereas there was no change in Pdi at high-frequency (100-Hz) stimulation. In Groups 2 and 3, during colforsin daropate administration, Pdi to each stimulus increased from fatigued values (P < 0.05). The increase in Pdi was larger in Group 3 than in Group 2 (P < 0.05). In Group 4, the augmentation of Pdi by colforsin daropate was abolished in fatigued diaphragm with an infusion of nicardipine. The integrated diaphragmatic electric activity did not change in any of the groups. We conclude that colforsin daropate improves, in a dose-dependent manner, contractility in fatigued canine diaphragm via its effect on transmembrane calcium movement.

IMPLICATIONS

Diaphragmatic fatigue is implicated as a cause of respiratory failure in normal subjects and in patients with chronic obstructive lung disease. Colforsin daropate improves contractile properties during diaphragmatic fatigue.

[Anesthetic management for left ventricular assist device implantation in patients waiting for heart transplantation]

We report the anesthetic management of patients with dilated cardiomyopathy who underwent left ventricular assist device implantation (LVAD). Anesthesia was induced and maintained with midazolam and fentanyl. Transesophageal echocardiography (TEE) and a PA catheter were useful for hemodynamic monitoring and management of the patients. Furthermore, TEE is useful for the early detection of inflow of the air which is absorbed by negative pressure derived from high LVAD support pressure. On starting LVAD support, evaluation of right ventricular function and treatment for right ventricular failure were important and necessary for the patients. Added to conventional therapy using catecholamines, inhaled nitric oxide may provide a favorable effect for right ventricular failure.

Effects of a thromboxane receptor antagonist (NT-126) and a thromboxane synthase inhibitor (OKY-O46) on protamine-induced circulatory changes in dogs

OBJECTIVE

To examine whether a thromboxane receptor antagonist, NT-126, or a thromboxane synthase inhibitor, OKY-046, prevents circulatory changes caused by protamine reversal of heparin and to evaluate the significance of thromboxane generation in the phenomena.

DESIGN

Prospective, randomized, controlled, animal study.

SETTING

A university research laboratory.

PARTICIPANTS

Twenty-four adult mongrel dogs.

INTERVENTIONS

According to the pretreatments, the animals were divided into 3 groups (n = 8 in each): (1) control (normal saline); (2) NT-126, 0.01 mg/kg; and (3) OKY-046, 1 mg/kg. Under general anesthesia, all animals were anticoagulated with intravenous heparin, 200 IU/kg, 5 minutes before the pretreatment. Five minutes after the pretreatment, protamine sulfate, 2 mg/kg, was administered intravenously over 10 seconds. Hemodynamic variables were recorded repeatedly until 60 minutes after the protamine. Plasma thromboxane B2 level was determined at baseline and 10 minutes after protamine injection.

MEASUREMENTS AND MAIN RESULTS

The average values of mean arterial blood pressure and mean pulmonary artery pressure among the 3 groups in each period and values in each group over the study period were not significantly different. There was weak correlation between maximum percent increases in systolic pulmonary artery pressure or maximum percent decreases in systolic arterial blood pressure for 5 minutes after the protamine versus percent increases in plasma thromboxane B2 level.

CONCLUSION

Neither NT-126 nor OKY-046 appears to be effective in preventing protamine-induced circulatory changes in this dog model, suggesting that thromboxane generation alone is not responsible for the phenomena.

Flumazenil abolishes midazolam-induced increase in the work of nasal breathing

PURPOSE

To evaluate the effects of midazolam sedation followed by flumazenil antagonism on the work of nasal breathing in normal humans.

METHODS

We measured minute ventilation through the nasal route, respiratory frequency, nasal resistance (Rn) and the work of nasal breathing under three conditions: awake, during midazolam sedation, and after flumazenil antagonism in eight healthy human subjects. A custom-made, partitioned face mask enabled nasal and oral airflow to be measured separately. To calculate Rn and the work of nasal breathing, nasal mask and oropharyngeal pressure was also measured.

RESULTS

Total resistive work spent on the upstream segment of the nasal route per minute (Wn) (J x min(-1)) was greater during midazolam sedation (3.6 +/- 2.9) than while awake (1.6 +/- 0.9) and after flumazenil antagonism (1.7 +/- 0.6), respectively (mean +/- SD) (P < 0.05). Total resistive work spent on the upstream segment of nasal breathing (WnNnE) (JxL(-1)) increased from 0.31 +/- 0.14 to 0.75 +/- 0.61 after midazolam administration (P < 0.05) and decreased to 0.31 +/- 0.10 after flumazenil. Following midazolam administration, a strong correlation was observed between changes in WnNnE and changes in Rn r = 0.852, P < 0.0001), whereas there was no correlation between changes in Wn and changes in Rn r = 0.159, P = 0.279).

CONCLUSION

The work of breathing spent on the upstream segment of the nasal route increases during midazolam sedation and returns to baseline after flumazenil antagonism.

Different effects of olprinone on contractility in nonfatigued and fatigued diaphragm in dogs

PURPOSE

To evaluate the effects of low-dose olprinone, a phosphodiesterase III inhibitor, on contractility and its mechanism in nonfatigued and fatigued diaphragm in dogs.

METHODS

Thirty six pentobarbitone-anesthetized dogs were studied. In Group Ia (n=6), animals without fatigue, received no study drug. In Group Ib (n=6), dogs were given a bolus injection (10 ug x kg(-1)) followed by continuous infusion (0.1 microg x kg(-1) x min(-1)) of olprinone. In Groups IIa, IIb, and IIc (n=8 each), diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20-Hz applied for 30 min. After producing fatigue, Group IIa received no study drug; Group IIb was infused with olprinone (10 ug x kg(-1) loading dose plus 0.1 microg-kg(-1) min(-1) maintenance dose); Group IIc was infused with nicardipine (5 microg x kg(-1) x min(-1)) during olprinone administration. Diaphragmatic contractility was assessed by transdiaphragmatic pressure (Pdi).

RESULTS

No difference in Pdi was observed between Groups Ia and Ib. After fatigue, in Groups IIa, IIb, and IIc, Pdi at low-frequency (20-Hz) stimulation decreased from prefatigued (baseline) values (P < 0.05), whereas there was no change in Pdi at high-frequency stimulation (100-Hz). In Group IIb, during olprinone administration, Pdi at both stimuli increased from fatigued values (P < 0.05). In Group IIc, the augmentation of Pdi to each stimulus in fatigued diaphragm by olprinone was abolished with an infusion of nicardipine.

CONCLUSION

Low-dose olprinone does not affect contractility in nonfatigued diaphragm, but increases contractility in fatigued diaphragm via its effect on transmembrane calcium movement in dogs.

Reduction in standard MAC and MAC for intubation after clonidine premedication in children

We examined the relative effects of different doses of oral clonidine on the MAC for endotracheal intubation (MACEI) and the MAC for skin incision (MAC) in children. We studied 90 children (15 in each group) (age range 2-8 yr, weight 10-27 kg, height 89-124 cm) who received one of three preanaesthetic medications: placebo (control), oral clonidine 2 micrograms kg-1, or oral clonidine 4 micrograms kg-1 100 min before anaesthesia. Anaesthesia was induced and maintained with sevoflurane in oxygen and air without i.v. anesthetics and neuromuscular relaxants. The end-tidal sevoflurane concentration was kept constant for > or = 15 min before tracheal intubation or skin incision. MACs were determined using Dixon's 'up-and-down method'. Mean (SD) MACEIs of sevoflurane were 2.9 (0.1)%, 2.5 (0.1)% and 1.9 (0.1)% (P < 0.05), and MACs were 2.3 (0.1)%, 1.8 (0.1)% and 1.3 (0.1)% (P < 0.05), respectively, in control, clonidine 2 micrograms kg-1 and clonidine 4 micrograms kg-1 groups. The MACEIs and MACs decreased dose-dependently. The MACEI/MAC ratio (1.4) was not affected by clonidine.

The effect of sedative drugs on diaphragmatic contractility in dogs: propofol versus midazolam

IMPLICATIONS

a sedative dose (0.1 mg x kg(-1) x h(-1)) of midazolam, compared with a subhypnotic dose (1.5 mg x kg(-1) x h(-1)) of propofol, decreases the contractility of the diaphragm in dogs.

[Complications of hysteroscopical myomectomy: a report of two cases]

Hysteroscopical myomectomy has recently become popular in Japan. We present two patients who developed water intoxication and air embolism during surgery. [Case 1] Hysteroscopical myomectomy was performed under general anesthesia in a 37-yr-old woman (ASA I). Three hours after the start of the surgery, the patient's serum sodium concentration dropped to 118 mEq.l-1. She was treated with furosemide and recovered without sequelae. [Case 2] A 39-yr-old woman (ASA I) was scheduled to have hysteroscopical myomectomy under spinal and epidural anesthesia. Forty-five minutes after the start of the surgery, the patient complained of severe back pain, her blood pressure decreasing to 40 mmHg, SpO2 decreased to 80%, and ECG showed atrial fibrillation. After administration of ephedrine 5 mg, she recovered within 20 min. No abnormality was observed in echocardiogram, although some negative spots were detectable in a lung scintigraphy. She was discharged without sequelae. The hysteroscopical procedure is considered a non-invasive surgery, but the cases presented here emphasize the necessity for close attention to complications, especially pulmonary embolism.

Effect of xenon on diaphragmatic contractility in dogs

PURPOSE

This study was undertaken to examine the effect of xenon on diaphragmatic contractility in pentobarbitone- anesthetized, mechanically ventilated dogs.

METHODS

Twenty-one dogs were randomly allocated to three groups (n=7 of each): Group I received oxygen 100%; Group II received xenon 30% in oxygen; Group III received xenon 60% in oxygen. Diaphragmatic contractility was assessed by measuring transdiaphragmatic pressure (Pdi) generated during supramaximal stimulation of phrenic nerves at the neck at low-frequency (20-Hz) and high-frequency (100-Hz) stimulation, after maintaining 60 min of stable condition.

RESULTS

With inhalation of xenon at two different concentration (30% and 60%), no changes were observed in Pdi at either concentration. There was no difference in Pdi among the three groups.

CONCLUSION

Increasing the concentration of xenon to 60% has no effect on diaphragmatic contractility in dogs. This suggests that xenon may be used safely as an anesthetic with respect to respiratory muscle function.

The awakening concentration of sevoflurane in children

Sevoflurane is frequently used as a rapidly acting drug for the induction of anesthesia. We investigated the awakening concentration (MAC-awake) of sevoflurane in ASA physical status I children (age range 2-10 yr). We also investigated the effects of two different doses of clonidine (2 and 4 microg/kg) on the MAC-awake of sevoflurane. Subjects were randomly divided into three groups and received placebo (n = 24), clonidine 2 microg/kg (n = 17), or clonidine 4 microg/kg (n = 22) orally, 100 min before the induction of anesthesia. Sedation scores were estimated, by using a five-point scale, after entry into the operating room, and anesthesia was induced and maintained with sevoflurane in oxygen and balanced nitrogen, without an additional anesthetic. After surgery, end-tidal sevoflurane was decreased stepwise by 0.2% at 15-min intervals, a standardized verbal command was played to the patients, and the MAC-awake was determined. The MAC-awake of sevoflurane alone was 0. 78% +/- 0.24% (mean +/- SD), which decreased to 0.36% +/- 0.09% and 0.36% +/- 0.16% (both P <0.0001, compared with the control group) after premedication with the small and large doses of clonidine, respectively. The lack of any dose-response relationship might be explained by a plateau effect.

IMPLICATIONS

The awakening concentration of sevoflurane in unpremedicated children was 0.78%. Oral clonidine premedication at a dose of 2 microg/kg reduced the awakening concentration to 0.36%. However, an additional decrease in this value was not observed after the administration of the larger dose of clonidine premedication (4 microg/kg).

[Preparation and clinical evaluation of orally-disintegrating clonidine hydrochloride tablets for preanesthetic medication]

Orally-disintegrating tablets of clonidine hydrochloride, an alpha 2-adrenergic agonist, were prepared by the method of drying an aqueous suspension. The suspension was prepared using powdered lactose, and the composition ratio was 2:1 (powdered lactose: 0.048% clonidine hydrochloride solution). The suspension was dried under 4 +/- 1 degrees C (72 +/- 15% R.H.). We obtained tablets containing clonidine hydrochloride (40 micrograms/tablet). Physical properties of the tablets were as follows: hardness was 4.0 kgf, and disintegration time was 41.7 s (in vitro). In the clinical use, 8 patients, aged 1-2 year and weighing 9-11 kg, received approximately 4 micrograms/kg body weight as clonidine hydrochloride. The tablet was administered 90 min before entering the operating room. All patients were willing to accept the tablet. The quality of separation from parents, sedation and a mask acceptance were excellent on all patients. These results suggest that the orally-disintegrating tablet of clonidine hydrochloride was useful in a clinical situation for the preanesthetic medication of pediatric patients aged 1-2 year.

Plasma lidocaine, monoethylglycinexylidide, and glycinexylidide concentrations after epidural administration in geriatric patients

BACKGROUND AND OBJECTIVES

The purpose of this study was to evaluate the effect of age on the pharmacokinetics of lidocaine after epidural administration.

METHODS

Two percent lidocaine with epinephrine (5 microg/mL) was administered in two different age groups: an adult group (age 42 +/- 6 years, n = 10) and an elderly group (age 77 +/- 4 years, n = 10). Concentrations of lidocaine and its active metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), were measured in plasma samples obtained after 15, 30, 45, 60, 90, 120, 150, and 180 minutes of administration using high-performance liquid chromatography with ultraviolet detection.

RESULTS

No significant differences in plasma concentrations of lidocaine and its metabolites were observed between the two groups during the 3 hours of study. However, the elderly group showed significantly longer mean residence times (MRTs) and lower plasma clearance of lidocaine during the period compared with the adult group (P < .05). Plasma concentration ratios of MEGX/lidocaine were significantly lower in the elderly group after 2 hours of lidocaine administration (P < .05).

CONCLUSIONS

The increase in plasma lidocaine concentration after epidural anesthesia in elderly patients was not as high as anticipated. However, the elderly patients showed longer MRTs, lower clearance, and lower ratios of MEGX/lidocaine than did the adult (middle-age) patients.

Pretreatment with oral clonidine attenuates cardiovascular responses to tracheal extubation in children

This study was designed to evaluate the effects of diazepam and clonidine orally given preoperatively on cardiovascular responses to tracheal extubation in children. Fifty children, ASA physical status I, aged 4-10 years, undergoing minor elective surgery (inguinal hernia, phimosis) received orally, in a randomized, double-blind manner, diazepam 0.4 mg.kg-1 or clonidine 4 microgram.kg-1 (n=25 of each). These drugs were administered 105 min before an inhalational induction of anaesthesia. The same standard general anaesthetic technique was employed throughout. The maximum changes in heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were less in patients who had received clonidine than in those who had received diazepam (HR, 12 vs 24; SBP, 14 vs 26; DBP, 9 vs 16; mean, P < 0.05). In conclusion, compared to diazepam given orally, pretreatment with oral clonidine attenuates haemodynamic changes associated with tracheal extubation in children.

Modifications of the hemodynamic consequences of theophylline intoxication with landiolol in halothane-anesthetized dogs

PURPOSE

To examine the effect of landiolol (ONO-1101), a new ultra-short acting, highly selective beta1 blocker, on hemodynamic response to acute theophylline intoxication in anesthetized dogs.

METHODS

Thirty-four dogs were studied during halothane anesthesia. Aminophylline (50 mg x kg(-1) over 20 min followed by infusion at 1.75 mg x kg(-1) x hr(-1)) was administered as a model of acute theophylline intoxication. Dogs were randomly enrolled into four landiolol groups (0, 1, 10, 100 microg x kg(-1) x min(-1)) to treat tachyarrhythmias. Hemodynamic variables, heart rate (HR), systemic blood pressure (SBP), pulmonary artery pressure, pulmonary artery occlusion pressure, and cardiac output (CO) were measured along with plasma concentrations of theophylline, epinephrine, and norepinephrine.

RESULTS

After 60 min, plasma concentration of theophylline reached 46.6+/-4.0 (mean +/- SD) microg x ml(-1), HR increased from 129+/-21 to 193+/-27 bpm (P<0.0001) and CO increased from 1.6+/-0.5 l x min(-1) to 2.1+/-0.4 l x min(-1) (P<0.0001), whereas SBP decreased from 139+/-25 to 121+/-25 mm Hg (P<0.0001), with decreasing systemic vascular resistance. After intoxication, plasma epinephrine concentration increased from 125 +/-112 to 325+/-239 pg x ml(-1) (P<0.0001), and norepinephrine concentration from 103+/-61 to 133+/-61 pg x ml(-1) (P<0.0011). Landiolol 10 microg x kg(-1) x min(-1) decreased HR to pre-intoxication level, whereas HR returned to the intoxication baseline by 30 min after cessation of landiolol infusion.

CONCLUSIONS

Landiolol controlled tachyarrhythmias associated with theophylline toxicity. The optimal effective dose of landiolol was 10 microg x kg(-1) x min(-1).

Advancement of the mandible facilitates nasal breathing in human subjects sedated with midazolam

PURPOSE

To determine how anterior advancement of the mandible (ADM) affects spontaneous breathing through the nasal route in healthy human volunteers sedated with intravenous midazolam.

METHODS

In four subjects who exhibited nasal breathing during midazolam sedation (intravenous dose: 0.09+/-0.02 mg x kg(-1), mean +/- SD), we measured respiratory rate (RR), peak nasal inspiratory airflow rate (V(nIpeak)) peak nasal expiratory airflow rate (V(nEpeak), duty ratio (Ti/Ttot) and nasal resistance (Rn) before and after ADM. Nasal resistance was calculated by dividing the difference between nasal mask and oropharyngeal pressure by airflow rate at peak nasal inspiratory airflow.

RESULTS

The RR, V(nIpeak), and V(nEpeak) increased following ADM (P<0.001, respectively). On the contrary, Ti/Ttot decreased after ADM (P<0.001). Consequently, ADM decreased Rn from 30.4+/-40.8 to 5.0+/-5.6 (cm H2O x l(-1) x sec(-1)) (mean +/- SD) (P<0.001). In these four subjects, no respiratory airflow was observed through the oral route before and after ADM.

CONCLUSION

Advancement of the mandible decreases nasal resistance, thereby facilitating spontaneous breathing through the nasal route in normal humans sedated with midazolam.

Effects of oral clonidine premedication on side effects of intravenous ketamine anesthesia: a randomized, double-blind, placebo-controlled study

STUDY OBJECTIVE

To determine the effects of oral clonidine premedication on hemodynamic changes during the entire course of ketamine anesthesia and incidence of postoperative adverse reactions.

DESIGN

Randomized, prospective, double-blind, placebo-controlled study.

SETTING

Department of Anesthesiology, University of Tsukuba Hospital, Ibaraki, Japan.

PATIENTS

39 ASA physical status I and II patients undergoing superficial surgeries.

INTERVENTIONS

Placebo, clonidine 2.5 micrograms/kg, and clonidine 5 micrograms/kg groups received respective doses of oral clonidine 90 minutes prior to surgery. Anesthesia was induced with ketamine 2 mg/kg intravenously (i.v.), trachea was intubated, and anesthesia was maintained with 67% nitrous oxide, oxygen, and supplemental ketamine (1 mg/kg) when systolic blood pressure and heart rate (HR) exceeded 180 mmHg and 100 bpm, respectively.

MEASUREMENTS AND MAIN RESULTS

In the clonidine 2.5 micrograms/kg group, HR response to tracheal intubation was significantly less, while in the clonidine 5 micrograms/kg group both mean arterial pressure and HR responses were significantly suppressed, compared with the placebo group. Intraoperative coefficients of variations of HR were significantly less in both clonidine groups than the placebo group. Incidence of nightmare and degree of salivation were significantly less in the clonidine 5 micrograms/kg group than in the placebo group.

CONCLUSION

Oral clonidine 2.5 micrograms/kg and clonidine 5 micrograms/kg attenuates cardiostimulatory effects, while clonidine 5 micrograms/kg was associated with reduced incidence and severity of nightmare and salivation attributable to i.v. ketamine.

Ramosetron for preventing postoperative nausea and vomiting in women undergoing gynecological surgery

In a prospective, randomized, double-blinded, placebo-controlled trial, we evaluated the efficacy of ramosetron at three different doses (0.15, 0.3, and 0.6 mg) for the prevention of postoperative nausea and vomiting (PONV) after gynecological surgery. One hundred twenty women, ASA physical status I or II, aged 21-63 yr, received IV either placebo or ramosetron 0.15, 0.3, or 0.6 mg (n = 30 of each) at the completion of surgery. A standard general anesthetic technique and postoperative analgesia were used. A complete response, defined as no PONV and no need for another rescue antiemetic, during 0-3 h after anesthesia occurred in 40%, 47%, 87%, and 90% of patients who had received placebo and ramosetron 0.15, 0.3, and 0.6 mg, respectively. Corresponding results during 3-24 h after anesthesia were 43%, 50%, 87%, and 90%, and 24-48 h after anesthesia were 50%, 53%, 90%, and 93% (P < 0.05). Patients who had received ramosetron 0.3 or 0.6 mg were satisfied compared with those who had received placebo (P < 0.05). There were no serious clinical adverse events caused by the study drug in any of the groups. In conclusion, ramosetron 0.3 mg is an effective antiemetic for preventing PONV during 0-48 h after anesthesia in female patients undergoing gynecological surgery. Increasing the dose to 0.6 mg provided no further benefit.

IMPLICATIONS

This randomized, double-blinded, placebo-controlled trial in 120 women found the effective dose of ramosetron for preventing postoperative nausea and vomiting after gynecological surgery to be 0.3 mg.

Granisetron/dexamethasone combination for the prevention of postoperative nausea and vomiting after laparoscopic cholecystectomy

Dexamethasone decreases chemotherapy-induced emesis when added to an antiemetic regimen. This study was undertaken to evaluate the efficacy of granisetron/dexamethasone combination for preventing postoperative nausea and vomiting (PONV) after lapIaroscopic cholecystectomy (LC). In a prospective, randomized, double-blind manner, 120 patients (83 females), aged 25-65 years, were assigned to receive granisetron 40 microg kg-1 alone or granisetron 40 microg kg-1 plus dexamethasone 8 mg (n=60 of each) intravenously immediately before the induction of anaesthesia. A standardized general anaesthetic procedure and postoperative analgesia were used. A complete response, defined as no PONV and no need for another rescue antiemetic, during 0-3 h after anaesthesia was 83% with granisetron and 98% with granisetron plus dexamethasone, respectively (P=0.008); the corresponding incidence during 3-24 h after anaesthesia was 83% and 98% (P=0.008). No clinically important adverse events were observed in any of the group. In conclusion, prophylactic therapy with granisetron/dexamethasone combination is more effective than granisetron alone for the prevention of PONV after LC.

RETRACTED ARTICLE: Prophylactic antiemetic therapy with droperidol in patients undergoing laparoscopic cholecystectomy

PURPOSE

The incidence of postoperative nausea and vomiting (PONV) following laparoscopic cholecystectomy (LC) is relatively high when no prophylactic antiemetic is given. We have studied the efficacy of a commonly used and well-established antiemetic, droperidol, for the prevention of PONV in patients undergoing LC.

METHODS

In a randomized, double-blind, placebo-controlled study, 60 patients received placebo (saline) or droperidol 50 microg.kg(-1) (maximum dose, 2.5 mg) intravenously immediately before the induction of anesthesia (n = 30 of each). A standard general anesthetic technique was employed throughout.

RESULTS

A complete response, defined as no PONV and no need for another rescue antiemetic medication during the first 24 h after anesthesia, was 57% and 83% in patients who had received placebo and droperidol 50 microg.kg(-1), respectively ( P < 0.05). No clinically serious adverse events were observed in any of the groups.

CONCLUSION

Prophylactic antiemetic therapy with droperidol 50 microg.kg(-1) (maximum dose, 2.5 mg) is highly effective for preventing PONV after LC.

Prevention of postoperative vomiting with granisetron in paediatric patients with and without a history of motion sickness

A history of motion sickness is one of the patient-related factors associated with postoperative emesis. This prospective, randomized, double-blind, placebo-controlled study was undertaken to assess the efficacy of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, for preventing postoperative vomiting after tonsillectomy in 120 children with (n = 60) and without (n = 60) a history of motion sickness. Patients received a single dose of granisetron (40 micrograms.kg-1) or placebo (saline) (n = 30 of each) intravenously after an inhalation induction of anaesthesia. A complete response, defined as no vomiting, no retching and no need for another rescue medication, during the first 24 h after anaesthesia was 77% and 13% in patients with a history of motion sickness who had received granisetron or placebo, respectively; the corresponding incidence was 83% and 40% in those without it (P < 0.05; chi 2 test with Yates' continuity correction). No clinically serious adverse effects due to the study drug were observed in any of the groups. In conclusion, prophylactic antiemetic therapy with granisetron is effective for preventing postoperative emesis in children with a history of motion sickness as well as in those without it.

Propofol decreases diaphragmatic contractility in dogs

Volatile anesthetics depress diaphragmatic muscle function; however, no data are available regarding the effect of propofol on diaphragmatic contractility. We therefore studied this effect in dogs. Pentobarbital-anesthetized animals were divided into three groups of 10 each. Group I received only maintenance fluid; Group II was infused with a subhypnotic dose of propofol (0.1-mg/kg initial dose plus 1.5-mg x kg(-1) x h(-1) maintenance dose); Group III was infused with an anesthetic dose of propofol (0.1-mg/kg initial dose plus 6.0-mg x kg(-1) x h(-1) maintenance dose). We assessed diaphragmatic contractility by transdiaphragmatic pressure (Pdi). With an infusion of propofol in Groups II and III, Pdi at low-frequency (20-Hz) stimulation decreased from the baseline values (P < 0.05), whereas Pdi at high-frequency (100-Hz) stimulation did not change. Compared with Group I, Pdi at 20-Hz stimulation decreased during propofol administration in Groups II and III (P < 0.05). The decrease in Pdi was more in Group III than in Group II (P < 0.05). We conclude that propofol is associated with a dose-related inhibitory effect on diaphragmatic contractility in dogs.

IMPLICATIONS

Propofol is an effective IV anesthetic for the induction and maintenance of anesthesia. Subhypnotic and anesthetic doses of propofol decrease diaphragmatic contractility in dogs.

[Epidural anesthesia for cesarean section in a patient with dilated cardiomyopathy (DCM)]

A 23-year-old patient with dilated cardio myopathy (DCM) was scheduled for a cesarean section. We inserted an epidural catheter at the L 2/3 interspace and injected 1.5% lidocaine 6 ml with epinephrine 30 micro g and fentanyl 50 micro g. The analgesic level 15 minutes after injection was achieved up to the eighth thoracic dermatome. Dopamin 5 micro g.kg-1.min-1 was infused simultaneously. Analgesia was sufficient for the surgery, and heart rate and blood pressure were stable throughout the operation. The infant's apgar scores were 9 and 10. Epidural anesthesia is one of the options for cesarean section in pregnant women with DCM.

Plasma concentrations of lidocaine and its principal metabolites during continuous epidural infusion of lidocaine with or without epinephrine

BACKGROUND AND OBJECTIVES

The purpose of this study was to evaluate the effect of epinephrine on the absorption of lidocaine and the accumulation of active metabolites of lidocaine during continuous epidural anesthesia.

METHODS

Lidocaine was administered as an initial bolus of 5 mg/kg of 2% lidocaine solution followed by continuous infusion at 2.5 mg/kg/h. Patients in group I (n = 10) received lidocaine alone and patients in group II (n = 10) received lidocaine + epinephrine (5 pg/mL). Concentrations of lidocaine and its active metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), were measured in plasma samples obtained after 15 minutes, 30 minutes, and 1, 2, and 3 hours of infusion using high-performance liquid chromatography with ultraviolet detection.

RESULTS

Plasma lidocaine concentrations were higher in group I for the first 30 minutes; however, after 1 hour the levels were the same. Plasma MEGX and GX increased continuously in both groups. MEGX levels the were significantly higher in group I, but there was no significant difference in the sum of lidocaine + MEGX after 2 hours. There was no significant difference in GX levels between the two groups.

CONCLUSIONS

With respect to continuous epidural administration, addition of epinephrine to lidocaine solutions is ineffective after 2 hours for reducing the potential for systemic toxicity, because the sum of the plasma concentrations of lidocaine and its principal active metabolite, MEGX, are unaffected.

Early oral intake after arthroscopic surgery under spinal anesthesia

PURPOSE

We investigated the tolerability of early oral feeding (EOF) and its effects on the recovery of bowel function after spinal anesthesia.

METHODS

Thirty-one healthy adult patients undergoing knee arthroscopy or arthroscopic surgeries were randomly assigned to either the EOF group (n = 16) or the nil per os (NPO, n = 15) group. Spinal anesthesia was performed using hyperbaric tetracaine solution in all patients. Patients in the EOF group were allowed free access to solid and liquid food immediately after surgery before analgesia from spinal tetracaine resolved. Oral intake was prohibited for 24 h after completion of surgery in the NPO group.

RESULTS

Two patients in each group were mildly nauseated without the need for treatment. While degree of appetite determined by a visual analog scale before the first meal and time to the first gas emission showed no significant differences between groups, the median time to the first defecation in the EOF group (20.6 h) was significantly shorter than that of the NPO group (33.5 h, P = 0.005). No other complications associated with anesthesia, surgery, or EOF were noted.

CONCLUSION

Our results suggest that the restriction of EOF after surgery not involving the gastrointestinal tract under spinal anesthesia may not be rational, and that EOF may facilitate recovery of bowel function.

Ramosetron vs granisetron for the prevention of postoperative nausea and vomiting after laparoscopic cholecystectomy

PURPOSE

To compare the efficacy of ramosetron with granisetron for the prevention of postoperative nausea and vomiting (PONV) after laparoscopic cholecystectomy.

METHODS

In a randomized, double-blind study, 80 female inpatients received 3 mg granisetron or 0.3 mg ramosetron i.v. (n=40 of each) at the completion of surgery The standardized anesthetic included isoflurane and nitrous oxide in oxygen.

RESULTS

Complete response, defined as no PONV, during the first 24 hr (0-24 hr) after anesthesia was 85% with granisetron and 93% with ramosetron, respectively (P=0.241); the corresponding incidence during the next 24 hr (24-48 hr) after anesthesia was 63% and 90% (P=0.004). No clinically important adverse events due to the study drug were observed in any of the groups.

CONCLUSION

Ramosetron was more effective than granisetron for prevention of PONV during 0-48 hr after anesthesia for laparoscopic cholecystectomy.