Summary

Background and objective: Sevoflurane and propofol reduce the extent of necrosis and improve neurological outcome in rodent models of cerebral ischaemia and reperfusion. However, the effects of these anaesthetics on programmed cell death (apoptosis) are unclear. The present study investigates whether sevoflurane and propofol affect the expression of apoptosis-regulating proteins after cerebral ischaemia in rats.

Methods: Thirty-two fasted male Sprague–Dawley rats were tracheally intubated and the lungs were ventilated (isoflurane and N2O/O2 anaesthesia). After surgical preparation, the animals were randomly assigned to one of the following groups: control (n = 8): fentanyl intravenous (10 μg kg−1 bolus and 25 μg kg−1 h−1 infusion) with N2O/O2; sevoflurane (n = 8): 2.0% sevoflurane (end-tidal concentration) and O2/air; propofol (n = 8): 0.8–1.0 mg kg−1 min−1 propofol intravenous and O2/air; sham-operated (n = 8): 25 μg kg−1 h−1 fentanyl intravenous and N2O/O2, no cerebral ischaemia. Ischaemia (30 min) was induced by unilateral common carotid artery occlusion plus haemorrhagic hypotension to a mean arterial pressure of 30–35 mmHg. Four hours after cerebral ischaemia the brains were removed and the expression of apoptosis-regulating proteins (Bax, Bcl-2, p53, Mdm-2) was determined using immunofluorescence and Western-blot analyses.

Results: The expression of the pro-apoptotic protein Bax was greater in control animals than in sevoflurane or propofol anaesthetized rats and than in sham-operated animals. The concentrations of Bcl-2, p53 and Mdm-2 were not changed 4 h after cerebral ischaemia.

Conclusions: In addition to the anti-necrotic effects of sevoflurane and propofol, these anaesthetics also reduce the concentration of the apoptosis-inducing protein Bax as early as 4 h after ischaemia.

Summary

Background: Ketamine has been claimed to prevent acute opioid tolerance and hyperalgesia following acute exposure to opioids and its use has been proposed to decrease postoperative morphine consumption.

Methods: We conducted a randomized, double-blind, controlled study to evaluate the effect of intravenous (i.v.) ketamine on postoperative pain for 48 h after major ear, nose and throat (ENT) surgery. Thirty-one patients received i.v. ketamine 0.15 mg kg−1 before induction and 2 μg kg−1 min−1 during anaesthesia, and 31 patients were administered placebo in a similar manner. Anaesthesia was standardized with remifentanil and propofol, but without nitrous oxide. Standardized postoperative analgesia included paracetamol, methylprednisolone and morphine administered via a patient controlled analgesia (PCA) device.

Results: Intra-operative remifentanil consumption was not different between the ketamine group (0.25 ± 0.07 μg kg−1 min−1) and the control group (0.22 ± 0.07 μg kg−1 min−1). In the postoperative period, both groups experienced an identical pain course evolution. Cumulative morphine consumption was not significantly different between groups: at 24 h it was 33.3 ± 14.9 with ketamine and 31.9 ± 15.3 mg in controls, at 48 h it was 40.4 ± 20.6 mg with ketamine and 42.5 ± 25.9 mg in controls.

Conclusion: Low-dose ketamine added to a remifentanil-based propofol anaesthesia did not reduce morphine consumption after major ENT surgery.

Summary

The mitochondrial myopathies consist of a heterogeneous group of disorders caused by structural and functional abnormalities in mitochondria leading to involvement of the nervous system and muscles as well as other organ systems. The peculiar genetic characteristics of mitochondrial DNA impart distinctive properties to these disorders. The pathophysiology is presented. The methods employed in making the correct diagnosis, the preoperative patient assessment and correction of metabolic dysfunctions and anaesthetic techniques used, are highlighted. The conditions are briefly reviewed and suggestions are made for the safe anaesthetic management of affected patients.

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 laparoscopic cholecystectomy (LC). In a prospective, randomized, double-blind manner, 120 patients (83 females), aged 25–65 years, were assigned to receive granisetron 40 μg kg−1 alone or granisetron 40 μg 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.

Summary

Background: We have evaluated the use of the TOF-Guard® (TOF, train-of-four) acceleromyographic thumb responses to ulnar nerve stimulation in neonates and infants and the return of the responses after neuromuscular blockade.

Methods: Baseline acceleromyographic recording of thumb adduction to ulnar nerve stimulation during volatile anaesthesia was performed in 22 babies aged less than 30 weeks. At the start of stimulation the automatic set-up procedure of the TOF-Guard® was used to see if a 100% control twitch height could be achieved. Irrespective of the ability to achieve a 100% control twitch height, TOF stimulation was used thereafter. When no automatic 100% control twitch could be reached, the transducer signal gain factor was set manually to obtain a 100% value. In 14 of the 22 children the recovery after neuromuscular blockade with rocuronium 0.3 mg kg−1 was recorded.

Results: In nine of 22 patients a 100% baseline twitch height was obtained with the automatic set-up. In the other 13 babies the TOF-Guard® display indicated that the transducer signal was too low. The mean time to recovery of control twitch to 75% of baseline after rocuronium 0.3 mg kg−1 was 51 min (SD = 21) and the time to recovery of the TOF ratio to 70% was 49 min (SD = 19). The mean final twitch height and TOF after recovery from rocuronium blockade were 101% (SD = 15) and 92% (SD = 12), respectively.

Conclusion: The recovery of the responses after neuromuscular blockade to near baseline values shows that acceleromyography can be used to measure neuromuscular block and recovery in neonates and infants.

Summary

Background and objective: The electroencephalographic Narcotrend Index (NI) is a measure of the hypnotic component of general anaesthesia. The purpose of this study was to evaluate the impact of Narcotrend guidance on propofol consumption and emergence times in children receiving total intravenous anaesthesia with propofol and remifentanil. Methods: Thirty children, aged 1–11 yr, scheduled for paediatric urological surgery were enrolled. Remifentanil was given to all patients at a constant infusion rate of 0.3 μg kg−1 min−1 throughout anaesthesia. Patients were randomly allocated to receive a continuous propofol infusion adjusted either according to a conventional clinical practice (Group C: n = 15) or guided by Narcotrend monitoring (Group NI: n = 15; target NI 60 ± 5). All patients were connected to the Narcotrend Monitor, but in Group C the anaesthetist was blinded to the screen of the monitor. Propofol consumption (mg kg−1 h−1) and emergence times (min) were the primary and secondary outcome measures. Results: Propofol consumption (median [inter-quartile range]) was significantly lower in Group NI compared to Group C (NI: 7.0 [6.4–8.2] vs. C: 9.3 [8.3–11.0] mg kg−1 h−1; P < 0.001), whereas Log-Rank-analysis revealed no intergroup difference in emergence times (Group NI: mean [95% confidence interval (CI)] 12.8 [11.2–14.4] min; Group C: 16.4 [12.6–20.2] min; P = 0.10). Haemodynamic variables remained stable within age-related limits, and there were no observations of adverse events, especially no clinical signs of intraoperative awareness in any patient. Conclusion: Narcotrend monitoring for guidance of propofol/remifentanil anaesthesia in children results in reduced propofol consumption compared to a conventional clinical practice.

Summary

Background and objective: The cerebral state index (CSI™) derived from a new small handheld electroencephalogram monitor was studied during routine day surgical anaesthesia titrated according to the bispectral index (BIS™). The objective was to determine the degree of agreement between the two monitors. Methods: Anaesthesia was induced with propofol and fentanyl (0.1 mg) in 38 patients undergoing general anaesthesia for routine day-surgery. Maintenance anaesthesia (sevoflurane (20/38), desflurane (10/38) or propofol (8/38)) titrated by BIS XP (Aspect Medical, Natwick, MA, USA) and BIS and CSI (cerebral State Monitor, Danmeter; Odense, Denmark) index values were recorded every minute. No patient received muscle relaxation. Observer's Assessment of Alertness/Sedation rating scale was used to assess level of sedation. Results: Pair-wise recordings (914) of CSI and BIS were collected. The indices showed similar pattern and decreased with increasing level of sedation, however with large ranges for each level of sedation. Median indices were similar during surgery (BIS: 50 (14–89); CSI: 51 (7–88)) and both indices increased (P < 0.01) when minor movements occurred (BIS 65 (40–83); CSI 67 (40–89)). During maintenance of anaesthesia CSI > 20% from BIS-index in 24% of readings, and on rare occasions CSI indices deviated >100% from the BIS reading. When BIS < 40, CSI decreased slower than BIS and with wider spreading. Conclusions: When used for day-surgery anaesthesia without muscle relaxation, CSI and BIS show similar patterns and numerical values but with the incidence of occasionally large discrepancies between pair-wise readings. Which monitor is the more dependable remains to be established and cannot be implied from this initial explorative study.

Summary

Background: The purpose of this study was to assess whether the addition of intravenous magnesium sulphate (Mg) at the induction of anaesthesia to a balanced anaesthetic protocol including wound infiltration, paracetamol and tramadol resulted in improved analgesic efficiency after radical prostatectomy. Methods: We conducted a randomized, double-blind, controlled study. Thirty ASA I or II males scheduled to undergo radical retropubic prostatectomy with general anaesthesia were prospectively assigned to one of the two groups (n = 15 each). The Mg group (Gr Mg) received 50 mg kg−1 of MgSO4 in 100 mL of isotonic saline over 20 min immediately after induction of anaesthesia and before skin incision. The patients in the control group (Gr C) received the same volume of saline over the same period. At the time of abdominal closure, wound infiltration with 190 mg (40 mL) of ropivacaine was performed in both groups. Pain was assessed by a 10-point visual analogue scale in the recovery room starting from the time of tracheal extubation. Standardized postoperative analgesia included paracetamol and tramadol administered via a patient-controlled analgesia device. Results: In the postoperative period, both groups experienced an identical pain course evolution. Cumulative mean tramadol dose after 24 h was 226 mg in the magnesium group and 446 mg in the control group (P < 0.001). Postoperative nausea occurred in two patients in each group. Two vs. eight patients required analgesic rescue in magnesium and control groups, respectively (P = 0.053). Conclusions: This study shows that intravenous magnesium sulphate reduces tramadol consumption when used as a postoperative analgesic protocol in radical prostatectomy.

Two daily doses of oral Harpagophytum extract WS 1531 (600 and 1200, respectively, containing 50 and 100 mg of the marker harpagoside) were compared with placebo over 4 weeks in a randomized, double-blind study in 197 patients with chronic susceptibility to back pain and current exacerbations that were producing pain worse than 5 on a 0–10 visual analogue scale. The principal outcome measure, based on pilot studies, was the number of patients who were pain free without the permitted rescue medication (tramadol) for 5 days out of the last week. The treatment and placebo groups were well matched in physical characteristics, in the severity of pain, duration, nature and accompaniments of their pain, the Arhus low backpain index and in laboratory indices of organ system function. A total of 183 patients completed the study. The numbers of pain-free patients were three, six and 10 in the placebo group (P), the Harpagophytum 600 group (H600) and the Harpagophytum 1200 group (H1200)respectively (P=0.027, one-tailed Cochrane–Armitage test). The majority of responders’ were patients who had suffered less than 42 days of pain, and subgroup analyses suggested that the effect was confined to patients with more severe and radiating pain accompanied by neurological deficit. However, subsidiary analyses, concentrating on the current pain component of the Arhus index, painted a slightly different picture, with the benefits seeming, if anything,to be greatest in the H600 group and in patients without more severe pain, radiation or neurological deficit. Patients with more pain tended to use more tramadol, but even severe and unbearable pain would not guarantee that tramadol would be used at all, and certainly not to the maximum permitted dose. There was no evidence for Harpagophytum-related side-effects, except possibly for mild and infrequent gastrointestinal symptoms.

Following administration of 0.6 mg kg−1 rocuronium, the pharmacokinetics and the pharmacodynamics were studied in six obese and six control (normal weight) patients receiving balanced anaesthesia. Twelve gynaecological patients were allocated into two groups, according to body mass index (normal weight: body mass index: 20–24, obese weight: body mass index > 28). Venous plasma concentrations were determined by high-pressure liquid chromatography before administration of rocuronium, at 1, 2, 4, 6, 8,10, 15, 20, 25, 30, 35, 40, 48, 60, 75, 120, 180, 240, 300, 360 and 420 min after administration of rocuronium and at recovery of single twitch to 25% and 75% of control twitch height. Onset time was shorter (NS) in the obese compared with normal weight (obese weight: 65 ± 16, normal weight: 100 ± 39 s, mean±SD). Duration 25% (obese weight: 29.5 ± 5.3, normal weight: 28.4±5.3 min) and spontaneous recovery time (obese weight: 12.6 ± 2.7, normal weight: 12.5 ± 2.3 min) did not show any differences between the two groups. The pharmacokinetics of rocuronium were comparable in the two groups. The volume of distribution at steady state Vss (mL kg−1) was 208 ± 56 in normal weight and 169 ± 37 in obese weight. Distribution (T1/2α) and elimination half-life (T1/2β) as well as mean residence time were 15.6 ± 3.7, 70.3 ± 23.9 and 53.2 ± 9.8 min in normal weight and 16.9 ± 3.8, 75.5 ± 25.5 and 51.1 ± 18.9 min in obese weight,respectively. Also, no differences were observed in plasma clearance (3.89 ± 0.58 in normal weight and 3.62 ± 1.42 mL kg−1 min−1 obese weight). This study indicates that the pharmoacodynamics and pharmacokinetics of rocuronium are in female patients not altered by obesity.

Summary

Background and objective: Unanticipated difficulty in tracheal intubation in an anaesthetized patient has always been a cause of concern to anaesthesiologists. This difficulty may lead to morbidity and mortality. This survey was carried out to determine the technique commonly favoured in centres in the Oxford region in the UK for the management of unanticipated difficult intubation.

Methods: We conducted a clinical scenario-based questionnaire survey of 181 anaesthesiologists in the Oxford region. In this scenario, difficulty in endotracheal intubation is recognized only after induction of anaesthesia. A number of options were available to deal with this situation. We used this scenario as a tool to gain insight into the training and the training needs of anaesthesiologists at various levels of training.

Results: Of the 181 questionnaires sent, we received 143 (79%) completed replies. The vast majority (141/143 (99%)) of anaesthesiologists would use a gum-elastic bougie together with head and neck positioning and optimal external laryngeal manipulation to gain the best attempt at intubation. If intubation still failed, overall 129/143 (90%) had a back-up plan, while 14/143 (10%) had no plan. Flexible fibreoptic techniques were more commonly planned by 92/143 (64%) anaesthesiologists compared to blind techniques which were less commonly planned by 37/143 (26%) anaesthesiologists. Differences in choice of technique among anaesthesiologists in teaching and district general hospitals were not significant (P = 0.87). Overall, trainees were less likely to choose fibreoptic techniques compared to consultants (P = 0.0009) and would use blind techniques or ask a more experienced colleague to take over. The main reason for the choice was previous experience with the technique.

Conclusions: Although fibreoptic techniques were most commonly planned, these were less often chosen by trainees than consultants due to lack of experience/training, while unavailability of intubating laryngeal mask airway (Intavent®) was an additional issue precluding its use as an adjunct to intubation.

Summary

Background and objectives: Postoperative pain is a common problem following ambulatory breast augmentation surgery. This study was performed to compare standard of care (oral analgesics) with patient-controlled incisional regional analgesia (PCRA) for postoperative pain management at home for 48 h. A second aim was to compare the analgesic efficacy of ropivacaine 0.25% vs. 0.5%. Methods: Surgery was performed under local anaesthesia and monitored anesthesia care. Sixty adults (ASA 1–2) were randomized to one of two groups. Patients in Group PCRA could self-administer ropivacaine 0.25% 10 mL in the left breast and ropivacaine 0.5% in the right breast. Patients in Group T (tablets) received our standard of care treatment, i.e. oral paracetamol 1 g four times a day and oral ibuprofen 500 mg three times a day. Parameters measured included: analgesic requirements (in post-anesthesia care unit, PACU and post-discharge), pain intensity (visual analogue scale), patient satisfaction, global analgesia, side-effects, and quality of recovery. Results: Pain scores were significantly lower in Group PCRA compared to Group T at all time periods (P < 0.05). No differences were found in pain scores between the right and left breasts. Significantly more patients in Group T requested analgesics in the recovery unit (27 vs. 7; P = 0.001) and also at home (20 vs. 11; P < 0.02). More patients in the tablet group had nausea and vomiting (10 vs. 3; P < 0.05). Global analgesia on day 2 was significantly better in PCRA group; however, patient satisfaction was similar in both groups. More patients in the tablet group had sleep disturbance and woke up at night due to pain. Conclusions: Pain relief after ambulatory breast augmentation is superior with incisional PCRA when compared to oral analgesic combination of paracetamol and ibuprofen. Incisional PCRA was associated with minimal side-effects and less sleep disturbance. There was no difference in the analgesic efficacy between ropivacaine 0.25% and 0.5%.

Summary

Background and objective: Previous studies mainly conducted on elective patients recommend doses of 0.9–1.2 mg kg−1 rocuronium to obtain comparable intubation conditions with succinylcholine 1.0 mg kg−1 after 60 s during a rapid-sequence induction. We decided to compare the overall intubating conditions of standard doses of rocuronium 0.6 mg kg−1 and succinylcholine 1.0 mg kg−1 during a strict rapid-sequence induction regimen including propofol and alfentanil. Methods: Male and female patients (ASA I–III) older than 17 yr scheduled for emergency abdominal or gynaecological surgery and with increased risk of pulmonary aspiration of gastric content were randomized to a rapid-sequence induction with succinylcholine 1.0 mg kg−1 or rocuronium 0.6 mg kg−1. Patients with a predicted difficult airway were excluded. A senior anaesthesiologist ‘blinded’ for the randomization performed the intubation 60 s after injection of the neuromuscular blocker. Intubating conditions were evaluated according to an established guideline. Tracheal intubation not completed within 30 s was recorded as failed. Results: 222 patients were randomized. Three patients had their operation cancelled and 10 did not fulfil the inclusion criteria. Clinically acceptable intubation conditions were present in 93.5% and 96.1% of patients in the succinylcholine group (n = 107) and the rocuronium group (n = 102), respectively (P = 0.59). Conclusions: During a rapid-sequence induction with alfentanil and propofol, both rocuronium 0.6 mg kg−1 and succinylcholine 1.0 mg kg−1 provide clinically acceptable intubation conditions in 60 s in patients scheduled for emergency surgery. Under the conditions of this rapid-sequence induction regimen rocuronium may be a substitute for succinylcholine.

Summary

Background and objective: Placement of central venous catheters in patients is associated with several risks including endocardial lesions and dysrhythmias. Correct positioning of central venous catheters in the superior vena cava is essential for immediate use. The objective of a first study was to evaluate the signal quality of an intravascular electrocardiogram (ECG) during position control using a guidewire compared with the customary fluid column-based ECG system, and to assess its efficacy of correct placement of the central venous catheter. A second study tested if dysrhythmias can be avoided by intravascular ECG monitoring during catheter and guidewire advancement.

Methods: The jugular or subclavian vein of 40 patients undergoing heart surgery or who were being treated in the intensive care unit was cannulated. Intravascular ECGs were recorded during position control, and guidewire and water column lead were compared in the same patient with regard to the quality of the ECG reading and P-wave enhancement. In another 40 patients, the guidewire was inserted only 10 cm and the central venous catheter advanced under guidewire ECG control. Correct position of all the central venous catheters was confirmed by chest radiography.

Results: All central venous catheters were correctly positioned in the superior vena cava. For the same catheter position, the P-wave was significantly larger in the guidewire ECG than in the fluid column system. No changes in the quality of the ECG were detected when the guidewire was advanced or withdrawn by 1 cm relative to the catheter tip. Cardiac dysrhythmias were not seen during ECG-monitored advancement of the guidewire.

Conclusions: ECG quality using a guidewire lead is superior to the water column-based system. Furthermore, it is independent from the exact position of the guidewire as related to the tip of the catheter. Using intravascular guidewire ECG during advancement can prevent induction of dysrhythmias.