Summary

Background and objective: Unlike midazolam, melatonin premedication is not associated with cognitive impairment in adults despite its anxiolytic properties. The use of melatonin as a premedicant in children has not been reported. This randomized, double-blind, placebo-controlled study compared the perioperative effects of different doses of melatonin and midazolam in children.

Methods: Seven groups of children (n = 15 in each) were randomly assigned to receive one of the following premedicants. Midazolam 0.1, 0.25 or 0.5 mg kg−1 orally, melatonin 0.1, 0.25 or 0.5 mg kg−1 orally each mixed in 15 mg kg−1 acetaminophen, or placebo only (15 mg kg−1 acetaminophen). Anxiety and temperament were evaluated before and after administration of the study drug, on separation from parents and on the introduction of the anaesthesia mask. At week 2 postoperatively, the behaviour of the children was measured by the Post Hospitalization Behaviour Questionnaire.

Results: Melatonin or midazolam each in doses of 0.25 or 0.5 mg kg−1 were equally effective as premedicants in alleviating separation anxiety and anxiety associated with the introduction of the anaesthesia mask. A trend was noted for midazolam to prolong recovery times as the dosage increased. The use of melatonin was associated with a lower incidence (P = 0.049) of excitement at 10 min postoperatively, and a lower incidence (P = 0.046) of sleep disturbance at week 2 postoperatively than that observed with midazolam and control groups. No postoperative excitement was noted in the melatonin groups at 20, 30 and 45 min.

Discussion: Melatonin was not only as effective as midazolam in alleviating preoperative anxiety in children, but it was also associated with a tendency towards faster recovery, lower incidence of excitement postoperatively and a lower incidence of sleep disturbance at week 2 postoperatively.

Summary

Background and objective: This study was performed to compare three supraglottic airway devices: the ProSeal laryngeal mask airway (PLMA), the laryngeal tube S (LTS) and the oesophageal–tracheal combitube (OTC) during routine surgical procedures.

Methods: Ninety American Society of Anesthesiologists (ASA) I–III patients scheduled for routine minor obstetric surgery were randomly allocated to the PLMA (n = 30), the LTS (n = 30) or the OTC (n = 30) group, respectively. The overall success rate, insertion time, cuff pressures and resulting airway leak pressures were determined as well as a subjective assessment of handling and the incidence of sore throat, dysphagia and hoarseness were performed.

Results: Insertion time until the first adequate ventilation was significantly (P < 0.0001) shorter in the PLMA (median 29 s; 25–75th percentile 25–48 s; range 10–161 s; success rate 100%) and in the LTS group (38 s; 30–44 s; 13–180 s; 100%) compared to the OTC group (75 s; 48–98 s; 35–180 s; 90%). In vivo cuff pressures and airway leak pressures increased with the inflating cuff volume in all devices and were highest in the OTC group. Postoperatively, patients in the PLMA and the LTS group complained significantly less about sore throat (P < 0.001 and 0.05) and dysphagia (P < 0.001 and 0.02) compared to the OTC group, while there was no difference regarding the incidence of hoarseness. Subjective assessment of handling was comparable with the PLMA and the LTS, but inferior with the OTC.

Conclusions: In conclusion, both PLMA and LTS proved to be suitable for routine surgical procedures and proved to be superior to the OTC which cannot be recommended for routine use.

Summary

Background and objective: Stellate ganglion block has been extensively used in clinical practice for the management of painful conditions such as cephalic, facial and upper limb pains yet its mechanism of action and its analgesic efficacy are poorly understood. Method: Formalin (3% 0.2 mL) was injected into the plantar region of the right upper limb paw in rabbits and 50 min after this injection, saline or bupivacaine 2.5% 0.5 mL was administered via a chronic implantation catheter near the right stellate ganglion. Behavioural modification, changes in heart rate and plasma norepinephrine release at different time points after formalin and bupivacaine or saline injection were observed. Finally, the cervical spinal cord was harvested and immunostaining for substance P and c-Fos was performed. Results: Formalin caused stress noxious behavioural changes and a significant increase in heart rate and norepinephrine release. These changes were inhibited by bupivacaine stellate ganglion block but not by saline injection. Immunoreactants of substance P were significantly decreased by formalin injection compared with that in controls. However, with bupivacaine injection, substance P levels were restored though not reaching the levels seen in the controls. Formalin injection also caused a significant increase of c-Fos expression in cervical spinal cord. This increase was not affected by stellate ganglion block. Conclusion: Stellate ganglion block can effectively alleviate nociceptive responses induced by formalin injection. The mechanism of its action may involve reduction of substance P in the spinal cord and plasma catecholamine release caused by noxious stimuli.

Summary

Introduction: We tested the hypothesis that repeated autoclaving removes protein deposits from the classic laryngeal mask airway (LMA). Methods: Twenty previously used LMAs were hand washed, machine washed, dried, autoclaved and randomly allocated into four equal-sized groups for repeat autoclaving on 0 (control), 1, 2 and 3 occasions. After the final autoclave cycle, the LMAs were immersed in a protein-staining solution, rinsed, dried and a high-resolution digital image taken of the dorsal and ventral surfaces. The severity of staining was scored by two blinded observers. Results: All LMAs were stained. There was no reduction in staining with repeat autoclaving. Conclusions: Repeat autoclaving does not remove protein deposits from the LMA.

Summary

Background and objective: Aprotinin administration may decrease the incidence of stroke associated with coronary artery bypass surgery by an unknown mechanism. Astrocytes exposed to hypoxia produce proinflammatory cytokines and upregulate intercellular adhesion molecule (ICAM)-1 on cerebral endothelium. This study investigated the effects of aprotinin on cerebral endothelial activation by hypoxic astrocytes in vitro.

Methods: Mouse astrocytes were exposed to hypoxia in an anaerobic chamber for 4 h followed by reoxygenation for 24 h. Astrocyte-conditioned medium (ACM) collected from mouse astrocytes subjected to hypoxia/reoxygenation (HR) or normoxia were applied to mouse cerebral endothelial cell (MCEC) cultures for 4 and 24 h in normoxia. Endothelial cells were preincubated for 1 h with aprotinin (1600 KIU mL−1) prior to exposure to ACM. Flow cytometry was used to estimate endothelial ICAM-1 expression. Interleukin (IL)-1β space concentrations in ACM were estimated with enzyme-linked immunosorbent assay (ELISA). Repeated comparisons were made using analysis of variance (ANOVA) and post hoc Tukey test as appropriate. P < 0.05 was considered significant. Data is presented as mean (standard deviation, SD).

Results: MCEC ICAM-1 expression was greater after 24 h exposure to HR-ACM compared to normoxic-ACM (mean channel flouresence (MCF) 107.5 (4.5) vs. 74.3 (4.5), respectively, P < 0.001). ICAM-1 expression was decreased by aprotinin preincubation compared to control (MCF 91.0 (1.1) vs. 107.5 (2.1), P = 0.006). Supernatant IL-1β concentrations in astrocytes exposed to HR were greater than those exposed to normoxia (7.1 (0.2) vs. 4.1 (0.2), P = 0.01).

Conclusions: This may be a neuroprotective mechanism associated with aprotinin administration.

Summary

Background and objectives: The sustained attention to response task (SART) test is a sensitive indicator of deficits in sustained attention and is simple to perform. Sustained attention is impaired for a short period after minor surgery under general anaesthesia but the magnitude and duration of this effect after major surgery is unknown. We used the SART test to investigate deficits in sustained attention in patients undergoing major surgery under general anaesthesia. Methods: The SART test was completed before surgery and at 24, 48 and 72 h postoperatively by 20 ASA I–II female patients (mean age 48.6 yr) undergoing total abdominal hysterectomy under general anaesthesia. It was also completed by 20 age-matched female controls at similar time intervals to evaluate the effect of repeated test performance. Results: There was a significant (P < 0.05) interaction between the groups in number of errors made (a measure of sustained attention deficit). The number of errors decreased in control subjects on repeated performance of the SART test but remained unchanged in patients undergoing total abdominal hysterectomy. The differences between groups remained significant after 72 h (P < 0.05). Patients' overall response times slowed significantly at 24–48 h (P < 0.05), but this recovered by 72 h after surgery. In contrast, overall response times in the control group tended to accelerate on repeated performance of the SART. Conclusions: The results of this study suggest that 72 h following major surgery patients have deficits in sustained attention compared with controls. Control subjects demonstrated a marked learning effect on repeated test performance compared with patients.

Summary

Background and objective: Percutaneous nephrolithotripsy (PCNL) is used for the fragmentation and removal of stones from the renal pelvis and renal calyceal systems. We compared the effects of propofol–alfentanil or propofol–remifentanil anaesthesia on haemodynamics, recovery characteristics and postoperative analgesic requirements during percutaneous nephrolithotripsy. Methods: Thirty non-premedicated patients were randomly allocated to receive either propofol–alfentanil (Group A) or propofol–remifentanil (Group R). The loading dose of the study drug was administered over 60 s (alfentanil 10 μg kg−1 or remifentanil 1 μg kg−1) followed by a continuous infusion (alfentanil 15 μg kg−1 h−1 or remifentanil 0.15 μg kg−1 min−1). Propofol was administered until loss of consciousness and maintained with a continuous infusion of 75 μg kg−1 min−1 in both groups. Atracurium was given for endotracheal intubation at a dose of 0.5 mg kg−1 and maintained with a continuous infusion of 0.4 mg kg−1 h−1. Mean arterial pressure heart rate, the total amount of propofol, time of recovery of spontaneous ventilation, extubation and eye opening in response to verbal stimulus and analgesic requirement were recorded. Results: In Group A, mean arterial pressure was higher at the first minute in the prone position, and during skin incision and lithotripsy, and heart rate was higher during skin incision and lithotripsy when compared with Group R (P < 0.05). The total amount of propofol did not differ between groups. Time of recovery of spontaneous ventilation, extubation and eye opening were significantly shorter in Group R than Group A (P < 0.05). Conclusions: Both propofol–remifentanil and propofol–alfentanil anaesthesia provided stable haemodynamics during percutaneous nephrolithotripsy, whereas propofol–remifentanil allowed earlier extubation.

Summary

Background and objective: The aim of the study was to report our experience concerning the effectiveness, complications and safety of spinal anaesthesia, and to determine whether spinal anaesthesia was effective in full-term infants undergoing elective inguinal hernia repair.

Methods: Sixty-eight full-term infants aged <6 months were included in the study. Infants were divided into three groups; Group I (<1 month, n = 20), Group II (>1 and <3 months, n = 26), and Group III (3–6 months, n = 22). All spinal blocks were performed under mask inhalation anaesthesia. A dose of bupivacaine 0.5% 0.5 mg kg−1 was used for infants under 5 kg and 0.4 mg kg−1 for those over 5 kg. Heart rate, mean arterial pressure, respiratory rate and SPO2 were recorded before and after spinal anaesthesia at 5 min intervals. Time to onset of analgesia, time to start of operation, duration of operation, anaesthesia and hospitalization, postoperative analgesic requirement and complications were recorded.

Results: Adequate spinal anaesthesia without sedation was better, time to obtain maximum cutaneous analgesia was shorter and need for sedation and postoperative analgesic requirement were significantly lower in Group I. Although heart rate, mean arterial pressure and respiratory rate decreased <20% in all groups following spinal analgesia, the decrease in Group I was lower than the others.

Conclusions: Spinal anaesthesia is an effective choice in inguinal hernia repair for full-term infants aged <1 month, providing excellent and reliable surgical conditions. However, this technique is not as useful for infants aged between 1 and 6 months.

Summary

Background and objective: Inhalation induction with sevoflurane provides acceptable conditions for tracheal intubation. Opioids significantly decrease the alveolar concentration needed to achieve tracheal intubation. The purpose of this study was to determine the target concentration of remifentanil providing excellent conditions for tracheal intubation with sevoflurane at 1 minimum alveolar concentration without muscle relaxant. Methods: Twenty-four consecutive patients, aged 18–50 yr, ASA I or II, were studied. Induction of anaesthesia was performed with sevoflurane at age-adjusted minimum alveolar concentration. Remifentanil was simultaneously administered using target-controlled infusion with the Minto model. Target plasma concentration of remifentanil was selected for each patient according to an up-and-down method. Results: The mean target concentration of remifentanil for successful tracheal intubation was 3.3 ng mL−1 (95% confidence interval: 2.6–3.9 ng mL−1). Arterial pressure, heart rate and bispectral index did not increase after tracheal intubation in the group of patients with successful intubation. Conclusions: Remifentanil at 3.3 ng mL−1 together with sevoflurane at 1 minimum alveolar concentration provides excellent conditions for tracheal intubation in 50% of patients.

Summary

Background and objective: Effective and early treatment of postoperative pain and nausea have become pivotal for the early discharge of patients after tonsillectomy. Opioid-based analgesia is standard practice but the use of non-steroidal anti-inflammatory drugs is discouraged due to their platelet inhibiting properties. The cyclo-oxygenase-2 selective non-steroidal anti-inflammatory drugs are effective analgesics and do not affect platelet function. We hypothesized that premedication with cyclo-oxygenase-2 selective non-steroidal anti-inflammatory drug in addition to paracetamol would provide effective analgesia and decrease opioid consumption during early recovery from tonsillectomy. Methods: In a randomized, placebo-controlled study of adult tonsillectomy patients (n = 40) one group (R-group; n = 20) was premedicated with paracetamol 1.5 g and rofecoxib 50 mg and a control group (P-group; n = 20) was premedicated with paracetamol 1.5 g and placebo. Morphine was used as rescue medication. Postoperative (24 h) pain scores (0–10), morphine consumption as well as intraoperative blood loss were recorded. Results: We found no overall difference in pain scores between the groups but significantly more patients in the placebo group had pain scores >5 within the first 8 h. The rofecoxib group consumed less morphine during the first 12 h. A lower intraoperative blood loss was observed in the rofecoxib group. Conclusion: Our results suggest an early although clinically minor analgesic benefit of the addition of a cyclo-oxygenase-2 selective non-steroidal anti-inflammatory drug to paracetamol as premedication for adult tonsillectomy.

Summary

Background and objective: We investigated whether a high bolus dose of cisatracurium (8× ED95) given at induction can provide muscle relaxation for the major part of a cardiac procedure with hypothermic cardiopulmonary bypass, avoid important postoperative residual curarization and cause no waste of product.

Methods: Twenty patients were randomly assigned either to Group 1 (n = 10) or Group 2 (n = 10). Those in Group 1 were given cisatracurium in a high bolus dose (0.4 mg kg−1). Those in Group 2 received cisatracurium 0.1mg kg−1 at induction followed after 30 min by a continuous infusion of cisatracurium. As an escape medication in case of patient movement, a bolus dose of cisatracurium 0.03 mg kg−1 was given.

Results: In Group 1 (large cisatracurium bolus dose), the clinical duration of effect (until T1/T0 = 25%) was 110 min. Six of 10 patients in Group 1 required additional boluses of cisatracurium intraoperatively. Four of these six had received an additional bolus near the end of surgery and had a train-of-four (TOF) ratio = 0 at the end. The other four patients in Group 1 had a final TOF ratio >0.9. In Group 2 (continuous cisatracurium infusion), only two patients had a TOF ratio >0.9 at the end of surgery, no patient moved and none received additional boluses. The total amount of cisatracurium used in the bolus and infusion Groups was 34.5 ± 7.8 and 21.3 ± 5.7 mg, respectively (P = 0.0004).

Conclusions: For continued neuromuscular block during hypothermic cardiac surgery, a high bolus dose of cisatracurium appears to be safe, although it is not an alternative to a continuous infusion, as its neuromuscular blockade does not cover the intraoperative period and a high incidence of movements occurs. In the patients who received a high bolus dose of cisatracurium, postoperative residual curarization appeared after additional boluses had been given. The consumption of cisatracurium by high bolus was significantly greater than with continuous infusion.

Summary

Background and objective: Metoclopramide is an antiemetic drug which inhibits plasma cholinesterase activity. We have compared the mivacurium infusion requirements and neuromuscular recovery after administration of metoclopramide to a group of adults compared to a control group.

Methods: Forty-five patients were randomized into three groups. Two groups received either 10 or 20 mg of intravenous (i.v.) metoclopramide and the third group received i.v. saline. Metoclopramide and saline were given 5 min before i.v. induction of anaesthesia. Plasma cholinesterase activity was measured before induction and 30 min after metoclopramide or saline injection. Neuromuscular block was monitored by accelerography using single and train-of-four (TOF) stimulation. The mivacurium intubation dose was followed by an infusion titrated every 5 min to maintain 95% block until the end of surgery when the infusion was stopped. Recovery from mivacurium was then monitored until complete.

Results: Mivacurium infusion rates were significantly lower in the metoclopramide groups. After 45 min of infusion, the infusion rates were 1.82 ± 0.8 and 2.1 ± 1 μg kg−1 min−1 in the 20 and 10 mg metoclopramide groups, respectively, and 6.8 ± 2.7 in the saline group. Time to recovery of TOF to greater than 90% was significantly prolonged in both metoclopramide groups compared to the saline group: 33.2 ± 7.2 and 29.5 ± 10.3 min in the metoclopramide 20 and 10 mg groups, respectively, compared to 22 ± 3.9 in the saline group (P < 0.001 for the 20 mg group compared to control).

Conclusion: Metoclopramide enhances the effect of a mivacurium infusion.

Summary

Background and objective: The use of remifentanil requires other analgesics for postoperative pain relief compared to fentanyl in patients undergoing craniotomy. This could possibly reduce the postoperative advantages of this short-acting opioid.

Methods: We compared remifentanil and fentanyl-based anaesthesia in a randomized observer and patient blinded trial on patients, undergoing an elective craniotomy. Twenty patients received anaesthesia using remifentanil with a small dose of piritramide (0.1 mg kg−1) after closure of the dura mater. Twenty patients underwent a fentanyl-based protocol. In both groups, anaesthesia was induced with thiopental and rocuronium, and maintained with 0.6–1 minimum alveolar concentration (MAC) isoflurane in a nitrous oxide/oxygen mixture 2 : 1 and rocuronium. Patients received 1 g of paracetamol rectally postoperatively. A visual analogue scale (VAS) for pain, the Glasgow Coma Score, a modified Aldrete Score, arterial carbon dioxide tension (PaCO2) and piritramide consumption were evaluated every half an hour postoperatively.

Results: No significant differences were found for pain, Aldrete or Glasgow Coma scores or for PaCO2 between the groups when controlled for age, although the pain and Glasgow Coma Scores were consistently higher and PaCO2 lower in the remifentanil group. Furthermore, 13 out of 20 patients in the remifentanil group requested extra piritramide as opposed to 7 out of 20 in the fentanyl group (P = 0.11).

Conclusions: Despite the intraoperative use of piritramide in the remifentanil group, patients experienced more pain postoperatively. A significant influence of age on pain intensity was found. The use of remifentanil with a small dose of piritramide of 0.1 mg kg−1 has no evident advantage over the use of fentanyl considering the postoperative conditions after craniotomy.

Summary

Background and objective: Neurological dysfunction is a common problem after cardiac surgery with cardiopulmonary bypass (CPB). Cerebral ischaemia associated with the use of CPB may result in a release of neuronal–ischaemic markers and a subsequent cerebral inflammatory response which may additionally release inflammatory cytokines. In order to locate the origin and to quantify the release of neuronal–ischaemic markers and cytokines we investigated arterial–cerebral venous concentration gradients during and after CPB in a clinical setting.

Methods: In twenty-five patients scheduled for coronary artery bypass grafting surgery we measured the plasma concentration of neuron-specific enolase, S-100β protein as well as interleukins (IL) IL-6, IL-8 and IL-10 from arterial and cerebral venous blood samples prior to surgery (baseline), during hypothermic CPB at 32°C, after termination of bypass, as well as 2, 4 and 6 h after admission to the intensive care unit.

Results: Arterial–cerebral venous concentration gradients of neuron-specific enolase, S-100β, IL-6, IL-8 and IL-10 were neither detectable during nor after CPB. Compared to the baseline period, S-100β and neuron-specific enolase significantly increased during hypothermic CPB. After termination of CPB, neuronal–ischaemic markers as well as cytokines were increased and remained elevated during the investigated time course without reaching baseline values.

Conclusions: Although we found an overall increase in plasma concentrations of neuronal–ischaemic markers, IL-6, IL-8 and IL-10 during and after CPB, arterial–cerebral venous gradients were not detectable for any of these parameters. Our results suggest that the increase of investigated parameters associated with the use of CPB are not primarily caused by a cerebral inflammatory response but rather reflect a release from other sources in the systemic circulation.

Summary

Background: In this double-blind randomized study, the analgesic effects of morphine alone and with methylprednisolone were examined in 72 patients undergoing arthroscopic knee surgery. Methods: At the end of arthroscopy, patients were allocated randomly to one of four groups to receive intra-articular administrations of saline, morphine 1 mg, morphine 5 mg or morphine 1 mg with methylprednisolone 40 mg. Preoperative and postoperative pain levels at rest and during movement (active flexion of the knee) were measured by a visual analogue scale (VAS). Postoperative analgesic requirements to alleviate pain were evaluated. Results: Pain scores were significantly lower for the patients who received 5 mg morphine and 1 mg morphine with 40 mg methylprednisolone than for those who received saline or 1 mg morphine. This was accompanied by a decrease in the postoperative consumption of analgesics and prolongation of the duration of pain relief. Conclusions: This study confirms that the analgesic effect of morphine given intra-articularly is dose dependent and that combination of methylprednisolone with morphine has an additive effect on analgesia.

Summary

Background and objective: Sedation is commonly used to facilitate diagnostic procedures in children. The aim of our study was to investigate sedation in children using propofol alone or combined with fentanyl or midazolam with regard to efficacy, adverse reactions or side-effects related to the drugs, ease of operation for the endoscopist, and time to discharge from the post-anaesthesia care unit. Methods: We prospectively studied 240 children, aged 1–12 yr of age, undergoing endoscopic procedures of the upper gastrointestinal tract. The patients were given an oral premedication with midazolam (0.5 mg kg−1) and were then randomly allocated to one of the three study groups: propofol alone (Group P), propofol with fentanyl 1 μg kg−1 (Group PF) or propofol with midazolam 0.1 mg kg−1 (Group PM). Additional doses of propofol given during the procedure were recorded. Adequacy of sedation and ease of procedure (easy, adequate, impossible) were evaluated by the endoscopist, who was blinded as to the drugs used. Results: The duration of the procedure and the recovery period were similar in the three groups. The number of patients requiring supplemental doses of propofol to permit safe completion of gastroscopy was 31 in Group P (=39%; eight of these required two additional doses), 14 in Group PM (=18%), and 11 in Group PF (=13%) (P < 0.05). There was a lower incidence of adverse events in Group PM and in Group PF than in Group P (P < 0.05). Conclusions: Propofol in combination with fentanyl or midazolam gives better sedation and ease of endoscopy than propofol alone.

Summary

Background and objective: Initial distribution volume of glucose (IDVG) reliably measures the central extracellular fluid volume in the presence of fluid gain or loss. We hypothesized that IDVG has a close relationship with intrathoracic blood volume (ITBV), which has recently been used as an indicator of cardiac preload. We therefore examined whether IDVG can correlate with ITBV in various fluid volume states.

Methods: Fourteen anaesthetized mongrel dogs were mechanically ventilated. ITBV and cardiac output were measured by single transpulmonary thermodilution technique. IDVG and indocyanine green derived plasma volume (PV-ICG) were determined by the administration of 100 mg kg−1 glucose and 0.5 mg kg−1 indocyanine green solutions, respectively, and calculated by applying a one-compartment model. Three sets of measurements were performed before and after haemorrhage (30 mL kg−1) and subsequent fluid volume loading (90 mL kg−1 of lactated Ringer's solution).

Results: A linear correlation was observed between IDVG and ITBV (r2 = 0.52, n = 42, P < 0.001) and between PV-ICG and ITBV (r2 = 0.44, n = 42, P < 0.001) throughout the procedures. A linear correlation was also observed between changes in IDVG and those in ITBV (r2 = 0.76, n = 28, P < 0.001). The ITBV/IDVG ratio during normovolaemia was 0.26 ± 0.04, which remained unchanged during the procedure.

Conclusion: Results showed that that IDVG has a linear correlation with ITBV, and support the concept that IDVG measurement has potential as a surrogate measure of ITBV in various fluid volume states.

Summary

Background and objectives: Failed endotracheal intubation is a principal cause of morbidity and mortality in anesthetized patients. The aim of this study was to investigate the efficiency of lateral neck radiography in predicting difficult intubation. Methods: In a prospective triple-blind study, 100 patients (aged 18–89 yr), scheduled for elective surgery were randomly selected. Lateral neck X-ray was obtained from each of the patients before operation. Several angles and parameters on the X-ray were proposed to illustrate a relationship with easy or difficult intubation. A radiologist recorded these angles before the operation. An anaesthesiologist also determined the Mallampati score preoperation. At the time of intubation, two other anesthesiologists performed a laryngoscopy and, according to established criteria, identified the patients as easy or difficult intubation. The results were then compared with each other. Results: Fifteen patients were identified as having difficult intubation (laryngoscopy Grades III and IV). Sensitivity and specificity of the Mallampati Class test were 26% and 100%, respectively. The sensitivity and specificity of the lateral neck X-ray for three measured angles were 100%. The positive and negative predictive values (NPVs) for those angles were 100% and for Mallampati classification were 100% and 80%, respectively. Conclusions: Compared to the Mallampati Class test, our method of analyzing the lateral X-ray, although not as easy and universally applicable as Mallampati Class test, proved to be a suitable method for predicting difficult intubation.

Summary

Background and objective: The phosphodiesterase-III (PDE-III) inhibitor enoximone-induced marked contractures in skeletal muscle specimens of malignant hyperthermia (MH) susceptible (MHS) human beings and swine. Whether this is a substance specific effect of enoximone or caused by inhibition of PDE-III remained unclear. Therefore, the effects of the PDE-III inhibitor amrinone in porcine MH normal (MHN) and MHS skeletal muscles were investigated.

Methods: MH-trigger-free general anaesthesia was performed in eight MHS and eight MHN swine. The MH status of the swine was determined by detection of the Arg615–Cys point mutation on chromosome 6 indicating MH susceptibility. Skeletal muscle specimens were excised for the in vitro contracture tests with amrinone. Amrinone was added cumulatively every 5 min to muscle specimens in order to obtain organ bath concentrations between 20 and 400 μmol L−1. The in vitro effects of amrinone on muscle contractures and twitches were measured.

Results: Amrinone-induced contractures in all skeletal muscle preparations. MHS muscles developed contractures at significantly lower bath concentrations of amrinone than MHN muscles. Contractures of MHS compared to MHN muscles were significantly larger at bath concentrations of 80, 100, 150, 200 and 400 μmol L−1 amrinone. Muscle twitches remained unchanged up to and including 200 μmol L−1 amrinone.

Conclusions: Inhibition of PDE-III in general elicited higher contractures in MHS than in MHN muscles. Therefore, a contribution of PDE-III and the cyclic adenosine monophosphate (cAMP) system in the pathophysiology of MH must be suspected.

Summary

Background and objective: Postoperative nausea and vomiting (PONV) is a frequent and unpleasant experience that may increase postoperative complications and costs. For surgical procedures with a high risk of PONV, prevention is preferable to treatment. In this study, the authors explore the dose–response relationship between granisetron administered just prior to the end of surgery and post-operative nausea and vomiting in patients undergoing abdominal hysterectomy. Methods: This was a randomized, double-blind, placebo-controlled, pilot study of post-operative nausea and vomiting prevention. Patients undergoing elective open abdominal hysterectomy requiring general anaesthesia received a single dose of granisetron 0.1, 0.2 or 0.3 mg or placebo administered approximately 15 min prior to the end of surgery. The primary efficacy end-point was the proportion of patients with no vomiting in the 0–6 h interval following medication administration. No inferential statistics were planned. Results: The proportion of patients with no vomiting episode in the 0–6 h interval after administration of study medication was higher in each granisetron treatment group (>90%) than in the placebo group (77%). Proportions of patients with no vomiting episodes in the 0–24 h interval were similar across treatment groups. Results of analyses of proportions of patients with no moderate or severe nausea episodes, proportions of those requiring rescue medication and times to first use of rescue medication suggested a treatment effect of granisetron relative to placebo in both the 0–6 and 0–24 h intervals. Similar proportions of patients in each treatment group reported at least one adverse event. Conclusions: Granisetron at doses of 0.1, 0.2 and 0.3 mg administered just prior to the end of surgery suggested a trend of improved efficacy compared to placebo in preventing postoperative nausea and vomiting in the first 6 h after abdominal hysterectomy. This pilot study did not identify a dose–response relationship.