It has been shown in healthy volunteers that a concentration of volatile anaesthetic lower than 1 minimum alveolar concentration provides unconsciousness. We tested the hypothesis that, using the electroencephalogram bispectral index, less than 1 minimum alveolar concentration of sevoflurane can produce unconsciousness in patients. Anaesthesia was induced and maintained with sevoflurane in N2O and O2 (33%) in 32 ASA I-II women undergoing laparoscopic tubal ligation. For the first patient, the sevoflurane concentration was adjusted to 1 minimum alveolar concentration with an end-tidal concentration of 0.7%. The electroencephalogram bispectral index values were used to determine the concentration to be used for the next patient. The ED50 (effective dose) measured using end tidal concentrations of sevoflurane for laparoscopic tubal ligation in a 40-year-old patient was 0.70% (CI 95%: 0.63–0.77) and ED95 0.83% (CI 95%: 0.75–0.90). None of the patients had any operation-associated recall. It is concluded that the sevoflurane concentration needed for laparoscopic tubal ligation is not lower than 1 minimum alveolar concentration.

Dimenhydrinate is an inexpensive antihistaminic drug, that is frequently used as an anti-emetic during anaesthesia. The popularity of the drug is contrasted by the lack of modern studies concerning its efficacy in reducing the incidence of post-operative nausea and vomiting. Thus, dimenhydrinate was compared with placebo in this prospective, randomized, double-blind study. One hundred and thirty-three female in-patients were studied. They were stratified according to the type of surgery (laparoscopic cholecystectomy, thyroid resection or knee arthroscopy) to ensure an homogenous distribution in both groups. General anaesthesia was induced with etomidate, fentanyl, vecuronium and maintained with enflurane in N2O/O2. Neuromuscular block was reversed with pyridostigmine/atropine. Patients in the dimenhydrinate group (n=67) received 62 mg dimenhydrinate intravenously after induction of anaesthesia. Placebo patients (n=66) received saline. Administration of dimenhydrinate (and placebo) was repeated three times during the 48-h study to mitigate the short half-life of the drug. Post-operative analgesia and anti-emetic rescue medication was standardized. Episodes of vomiting, retching and the need for additional anti-emetics were recorded. Nausea was assessed using a 10-cm visual analogue scale. Post-operative nausea and vomiting was rated as ‘none’, ‘mild’, ‘moderate’ and ‘severe’ using a fixed scoring algorithm. There were no differences between the two groups with regard to biometric data, type of surgery and distribution of risk factors for developing post-operative nausea and vomiting. In the dimenhydrinate group, more patients remained completely free from post-operative nausea and vomiting compared with placebo (dimenhydrinate: 38.8%; placebo:15.1%; P=0.004). The incidence of severe post-operative nausea and vomiting was also reduced from 39.4% to 14.9%. No relevant side effects were observed. Intra-operative dimenhydrinate, followed by three further administrations after surgery, reduces the incidence and the severity of post-operative nausea and vomiting without side effects. However, there still remained an unacceptable high number of patients who were not prevented completely from experiencing post-operative nausea and vomiting.

Post-operative nausea and vomiting is distressing for patients and can cause dissatisfaction and impaired well-being in the post-operative period. This study examined the question whether the reduced incidence of post-operative nausea and vomiting inevitably translates into improved clinical status and well-being. In this context high doses of droperidol were investigated. On the one hand, droperidol is known to be a powerful anti-emetic, but on the other hand there is concern about psychological effects, both in the pre- and the post-operative period. In this prospective randomized double-blinded study, droperidol (5–7.5 mg) was compared with midazolam (5–7.5 mg) used to supplement fentanyl-N2</O based anaesthesia, with respect to post-operative mood and well-being using a psychological questionnaire (Bf-S-test). Furthermore, the incidence of post-operative nausea and vomiting was recorded. Out of 160 patients undergoing thyroidectomy and laparoscopic cholecystectomy, data from 150 patients were analysed. The administration of droperidol significantly lowered the incidence of post-operative nausea and vomiting from 77.8% to 55.1% compared with midazolam (P=0.0059; χ2-test). Although post-operative nausea and vomiting is an independent risk factor for post-operative discomfort and bad mood, patients receiving droperidol showed impaired well-being 6 h after surgery. Well-being scores returned to pre-operative base-line values and did not differ between the two groups 24 and 48 h post-operatively. The reduced incidence of post-operative nausea and vomiting achieved with high dose droperidol does not equate with increased post-operative well-being. It is an important point at issue to decide whether smaller doses of droperidol that are commonly used for anti-emetic therapy are free of these side effects.

A review was undertaken of all 190 patients who were referred over 7 years, from 1991 to 1997 inclusive, for an epidural blood patch as a treatment for headache after dural puncture. The patterns of referral and symptoms, the distributions of age and gender and the effectiveness of the blood patch were examined. Most of the referrals (n=153) were after deliberate diagnostic dural puncture in neurology and neuroradiology, with a minority (n=28) used for anaesthesia and obstetrics, which were mostly inadvertent. Another nine cases were related to placement of an intrathecal catheter. The numbers of referrals per year reached a maximum in 1995 before falling again, a curious inverse relation to the number of invasive neuro-radiological diagnostic procedures. Most of the patients were between 30 and 50-years-old, with 25 younger than 30 and 14 older than 60. Women accounted for 70% of the referrals for headache, although the gender ratio amongst patients subjected to at risk procedures appeared closer to 50:50. Neckache accompanied the headache in 85% of cases, auditory problems were volunteered by three patients and one patient had diplopia for 6 weeks. Of the 190 patients who were referred, 186 received at least one patch, the symptoms in the remaining four being too mild or atypical to warrant blood patch treatment. This provided initial relief in all but two patients, one of whom received a further epidural blood patch with no effect. There was sustained relief of symptoms in 136 and a partial relapse in 38 patients, which resolved without needing any further blood patch. A second patch was provided for seven patients and a third for three patients, of whom two were cured. Of the patients who needed more than one blood patch, nine were after inadvertent dural puncture with a Tuohy needle and, of these patients, six were in labour. A total of 200 patches were provided in all for the 186 patients and all but three patients had a satisfactory outcome. Epidural blood patches are effective in treating headache after dural puncture, but less successful than is commonly believed, especially after inadvertent dural taps. A relapse after treatment does not always require a second patch. Specialities other than anaesthesia seemed reluctant to accept the benefits in both cost and comfort of using needles of improved design for dural puncture.

We have compared the efficacy of granisetron with perphenazine in the prevention of vomiting after tonsillectomy with or without adenoidectomy in children. In a prospective, randomized, double-blind study, 90 paediatric patients, ASA I, aged 4–10 years, received granisetron 40 mg kg−1 or perphenazine 70 mg kg−1 (n=45 each) intravenously immediately after an inhalation induction of anaesthesia. A standard general anaesthetic technique was employed throughout. A complete response, defined as no emesis with no need for another rescue antiemetic, during the first 3 h (0–3 h) after anaesthesia was 87% with granisetron and 78% with perphenazine (P=0.204). The corresponding incidence during the next 21 h (3–24 h) after anaesthesia was 87% and 62% (P=0.007). No clinically serious adverse events were observed in any of the groups. We conclude that granisetron is a better anti-emetic than perphenazine for the long-term prevention of post-operative vomiting in children undergoing general anaesthesia for tonsillectomy.

Epidural analgesia is one of the preferred methods of analgesia for labour. The aim of the present survey was to evaluate current practice in obstetric analgesia in departments of anaesthesia and to make a comparison with former surveys from Germany and other countries. Questionnaires on the practice of pain relief, especially epidural analgesia, during labour and delivery were sent to 1178 anaesthesic departments in Germany in the second half of 1996. Five hundred and thirty-two completed replies were received, which represent 46.9% of all German obstetric units. The majority of the departments of anaesthesia practising epidural analgesia have an epidural rate of less than 10% and 10.2% of the departments do not offer this method to their parturients. In 86.8% of all units performing epidural analgesia, the epidural catheter is placed by an anaesthetist. Only 6.5% of the units provide a 24-h epidural service which is exclusively assigned to labour and delivery. In 77.8% of the units, this service is not exclusively assigned to obstetrics, but also to other duties. Of the obstetric units offering epidural analgesia, 14.7% have no epidural service at night. Plain local anaesthetics for epidural analgesia are used by 55.9% of the departments, a combination of local anaesthetics with epidural opioids by 28.7%. Epidural analgesia is predominantly (82.2%) maintained by intermittent bolus administration. Although the rate of epidural analgesia increased during recent decades, this method is not offered to all parturients. Further improvements in the use of epidural analgesia for labour seem to be necessary.

Lignocaine added to the anaesthetic preparation Diprivan® reduces propofol induced pain on injection. This effect is due to a drop in pH which decreases the content of propofol in the aqueous phase of the soya bean emulsion. This in turn changes the electrostatic forces in the emulsion and destabilization occurs. The effect of lignocaine on the anaesthetic potency of propofol was validated in a randomized blind study in the rat. The induction dose of 1% propofol mixed with 1% lignocaine (10+1) was significantly higher when compared with the induction dose of propofol 1% given after a separate injection of 1% lignocaine (9.4±5.5 vs. 5.6±5.2 mg; P<0.05). The duration of sleep was shorter in rats injected with propofol 1% mixed with lignocaine 1% (10+1) compared with those given 1% lignocaine and 1% propofol in separate injections (160±181 vs. 375±202 s; P<0.05). The anaesthetic potency of propofol was not significantly changed by the addition of either saline or hydrochloric acid. The anaesthesia inducing effect was not time-dependent. A similar lower potency was observed for a solution stored for 4 h compared with one freshly prepared, although sleeping time was longer (9.2±6.8 mg; 428±110 s) as compared with the 4 h mixture. The results indicate that lignocaine altered the propofol preparation. The reduced anaesthetic potency of propofol after addition of lignocaine is not due to the resultant drop in pH, which is known to occur.

We evaluated the relation between dose and response for the neuroprotective effect of propofol in a rat model with incomplete cerebral ischaemia. For clarification of the mechanism of neuroprotection, plasma catecholamines and tumour necrosis factor-α levels were measured. Three doses (low, moderate and high-dose) of propofol were tested. These produced, respectively, a low amplitude, slowing and a burst-suppression pattern of electroencephalographic activity. Incomplete cerebral ischaemia was produced by right carotid artery occlusion combined with haemorrhagic hypotension (35 mmHg) for 30 min. Neurological outcome at 72 h post-ischaemia in the high-dose group was significantly better than that in both low-dose and moderate-dose groups. Propofol exhibited a trend in the dose-related attenuation of the increases in plasma adrenaline and noradrenaline during ischaemia. Tumour necrosis factor-α increased during and after ischaemia in all groups with no intergroup differences. The results indicate that a burst-suppression dose of propofol provides neuroprotection. The protective effect can not be completely explained by the attenuating effect on circulating catecholamines.

Gamma hydroxybutyric acid, a central inhibitory neurotransmitter and a cerebral metabolite of gamma-aminobutyric acid, is present in high concentrations in the mammalian hypothalamus and basal ganglia. Its sodium salt gamma hydroxybutyrate has been effectively used as an intravenous anaesthetic agent, and as an oral sedative, and in the management of the alcohol withdrawal syndrome. In an animal model, using 72 Wistar strain rats allocated to one of six groups of 12 animals each, with implanted lumbar intrathecal catheters, we examined whether gamma hydroxybutyrate, 20% 40 μL (32 mg kg−1) administered alone or combined with fentanyl, gamma hydroxybutyrate 20% 20 μL (16 mg kg−1), fentanyl 0.005% 20 μL (4 mg kg−1) as an intrathecal bolus, provides intra-operative anaesthesia, comparable with that produced by intrathecal lignocaine. We demonstrated that gamma hydroxybutyrate, given by an intrathecal bolus in the rat model, produced reversible segmental antinociception, together with muscular relaxation of the abdominal wall and rear limbs. This is accompanied by moderate sedation without haemodynamic or respiratory depression. This agent may thus be promising for use as a spinal anaesthetic drug.

A 6-month-old boy with Sturge–Weber syndrome was scheduled for congenital glaucoma and left buphthalmus surgery. Physical examination revealed haemangioma throughout the right trigeminal nerve, congenital glaucoma, left megalocornea and bilateral buphthalmus. Examination of the eye was performed under general anaesthesia, was followed 2 days later by trabeculotomy. No premedication was given to the patient. After induction of anaesthesia with halothane, O2 and N2O muscle relaxation was achieved with atracurium and he was intubated gently. No difference was observed in vital signs during surgery. At the end of the operation he was given oxygen 100% and extubated, muscle relaxant reversal was with atropine and neostigmine. No complication was observed in the post-operative period.

We describe a case of paradoxical air embolism during orthotopic liver transplantation, early diagnosis, using intra-operative transoesophageal echocardiography after a circulatory failure, allowed early management by hyperbaric oxygen therapy.

Despite a low incidence of botulism in the industrialized world some cases occasionally occur in Germany after eating contaminated food. Because botulism is rarely seen, most physicians are unfamiliar with its early recognition and treatment. However, immediate intensive care treatment is important. We report the case of a previously healthy 54-year-old female who developed signs of botulism after eating vacuum packed smoked fish and developed severe respiratory insufficiency with difficult carbon dioxide elimination in the days following.