Sometimes progress is hard to see, when looking at the big picture, because there is very little of it. But sometimes progress is hard to see because the big picture is out of focus. When perioperative deaths ascribed to anaesthesia are in the order of 1 in 20 000 operations and even changes in major morbidity require massive sample sizes to detect, neuroanaesthesia's most emphatic yardstick of progress is too crude to measure advances that have occurred over the most recent decade. We clearly need to become more familiar with neuropsychological tests that can detect subtle changes. Today, for elective neurosurgery, we are primarily in the business of doing two things – pushing the envelope for surgical intervention to include cases that would have been considered too risky 15 years ago, and reducing the frequency of “Uncle-Joe-has-never-been-the-same-since-they-operated-on-his-brain syndrome”. Both of these areas of progress are empirically measurable, but we have not made much progress towards measuring them. Of course, this measurement problem plagues anaesthesiology generally, and we need to attend to it in general. Meanwhile, saying where we are relative to the recent past and the near future involves a lot of guesswork. What follows is my guesswork about progress in neurosurgical anaesthesiology.

We performed a prospective, randomized study comparing the efficacy and safety of remifentanil, propofol or both for conscious sedation during eye surgery under retrobulbar blockade. Forty-five unpremedicated patients were assigned to receive remifentanil (group R) (n=15, mean dosage: 0.05±0.03 μg kg−1 min−1), propofol (group P) (n=15, 1.5±0.5 mg kg−1 h−1) or a combination (group RP) (n=15, R: 0.03±0.01 μg kg−1 min−1; P: 0.7±0.2 mg kg−1 h−1). Haemodynamic responses were comparable among all groups. Minimum values for respiratory rate were lower in R patients (R: 7 vs. P and RP: 10 breaths min−1). Peri-operative blood gas analysis showed differences in maximum carbon dioxide tensions (R: 51.5 vs. P: 48.3 vs. RP: 45.5 mmHg) and decrease in minimum pH values (R: −0.06 vs. P: −0.0 vs. RP: −0.01). All group P patients reported mild to intense pain during retrobulbar block, while 53% of the group R patients were free from pain. In group RP, 60% of patients experienced no pain and the remaining 40% reported mild pain only. Remifentanil, applied as the sole agent, provided superior pain relief and patient comfort when compared with propofol, but produced greater respiratory depression and postoperative nausea. The combination of remifentanil and propofol provided haemodynamic stability, adequate spontaneous respiration and pain relief, with a low risk of untoward side effects.

A non-invasive ultrasound imaging technique (BladderScan) was used prospectively in an attempt to reduce the need for catheterization of the urinary bladder and the incidence of urinary tract infections after orthopaedic surgery. Over a 4-month period, in which 1920 patients were included, catheterization was performed if there was no spontaneous diuresis by 8 h after surgery. A total of 31% of these patients were catheterized, and 18 patients developed urinary tract infections. In a subsequent 4-month period, there were 2196 patients, catheterization was performed only if the bladder volume was more than 800 mL 8 h after surgery. The rate of catheterization decreased to 16%, and five patients developed urinary tract infections. In our patients, measuring bladder volume reduced the need for a urinary catheter and the likelihood of urinary infection.

Replacement of the aortic valve exposes the left ventricle to myocardial ischaemia and imposes on it abrupt changes in loading conditions and geometry. We studied the immediate changes in the left ventricular function of patients undergoing aortic valve replacement by transoesophageal echocardiography. Patients with aortic regurgitation responded to surgery with a decrease in global systolic function associated with a fall in preload. Patients with aortic stenosis showed an impairment in myocardial contractility and ventricular filling, and their global systolic function did not improve despite the marked reduction in afterload. This can be a consequence of inadequate myocardial protection and intra-operative ischaemic injury of the hypertrophic myocardium. Information provided by transoesophageal echocardiography contributes to optimal and individualized management of the period immediately after aortic valve replacement.

The increasing use of ambulatory surgery requires methods of anaesthesia that allow patients to be discharged soon after the operation is completed. Spinal anaesthesia is usually simple and quick, and the incidence of post-spinal headache has been reduced by using non-cutting small-gauge needles. Limiting the spread of spinal anaesthesia, as long as it still provides analgesia for surgery, should reduce the haemodynamic effects and speed recovery. Restricted spinal anaesthesia, intended to be unilateral using 0.18% hypobaric bupivacaine via a 25G or 27G Whitacre unidirectional needle, was compared with epidural anaesthesia (using a mixture of lignocaine and prilocaine) in 64 matched-pair patients undergoing ambulatory arthroscopy. Motor blockade, assessed for the specific myotomes L2 to S1, was significantly more unilateral in the spinal group. Two patients in the spinal group and nine patients in the epidural group were treated for hypotension (P < 0.05). One patient in the spinal group developed a post-spinal headache. One patient in the epidural group rated the anaesthesia poor.

The aim of this study was to compare the effect of three different induction techniques, with or without neuromuscular block, on tracheal intubation, haemodynamic responses and cardiac rhythm. Ninety children, aged 1–3 years, undergoing day-case adenoidectomy were randomly allocated to three groups: group TS received thiopentone 5 mg kg−1 and suxamethonium 1.5 mg kg−1, group H 5 Vol.% halothane and group PA alfentanil 10 μg kg−1 and propofol 3 mg kg−1 for induction of anaesthesia. No anticholinergics were used. Holter-monitoring of the heart rate and rhythm was started at least 15 min before induction of anaesthesia and continued until 3 min after intubation. Tracheal intubation was performed by an anaesthetist blinded to the induction method and judged as excellent, moderate or poor according to ease of laryngoscopy, position of vocal cords and incidence of coughing after intubation. Tracheal intubation was successful at the first attempt in all children in groups TS and H and but only in 80% in group PA (P=0.001). Intubating conditions were excellent in 22 (73%), 22 (73%) and one (3%) of the patients in groups TS, H and PA, respectively (P=0.001). Cardiac dysrhythmias (supraventricular extrasystole or junctional rhythm) occurred in two (7%) patients in groups PA and H each (NS). Bradycardia occurred in 0 (0%), four (14%) and six (21%) children in groups TS, H and PA, respectively (P=0.007 PA vs.TS, P=0.03 H vs. TS). In conclusion, induction of anaesthesia with propofol 3 mg kg−1 and alfentanil 10 μg kg−1 without neuromuscular block did not provide acceptable intubating conditions in children 1–3 years, although it preserved arterial pressure better than thiopentone/suxamethonium or halothane. Cardiac dysrhythmias were few regardless of the induction method.

Sixty patients were randomly assigned to two equal groups. Group I received epidural morphine 1 mg after surgery and used a patient-controlled analgesia device programmed to deliver morphine 0.2 mg h−1, 0.2 mg per bolus. Group II received an epidural loading dose of morphine 1 mg plus ketamine 5 mg and used a patient-controlled analgesia device programmed to deliver morphine 0.2 mg+ketamine 0.5 mg h−1, morphine 0.2 mg+ketamine 0.5 mg per bolus with a lockout time of 10 min. The mean morphine consumption was 8.6±0.7 mg for group I and 6.2±0.2 mg for group II. Although group II utilized significantly less morphine (P<0.05), pain relief was significantly better in group II than in group I (P<0.05) in the first 3 h. Vomiting occurred more frequently in group I (26%) than in group II (13%). The frequency and severity of pruritus and level of sedation were similar in the two groups. These findings suggest that patient-controlled epidural analgesia with morphine plus ketamine may provide effective analgesia with a lesser dose of morphine and fewer subsequent side effects, compared with patient-controlled epidural analgesia with morphine alone after lower abdominal surgery.

There is disagreement concerning the role of nitric oxide (NO) in general anaesthesia. The present study was conducted to determine whether the anaesthetic drug isoflurane alters levels of NO metabolites, NOx (NO2 and NO3), in the hippocampus of rats during and after anaesthesia. Results showed resting hippocampal NOx levels of about 20 pmol in freely moving control rats. Five minutes after the induction of isoflurane anaesthesia (4.72%=4 minimum alveolar concentrations, detected by righting reflex), there was loss of the righting reflex coincident with a significant elevation in hippocampal NOx levels. During isoflurane anaesthesia, the maximum NOx concentration rose ≈2.4-fold higher than control levels; the NO3 level increased about 5-fold higher than resting levels. NOx levels returned to control levels following discontinuation of the anaesthetic. When rats were pre-treated with L-NG-nitro arginine methyl ester, an NO synthase-inhibitor, the isoflurane-induced increases in NOx were markedly suppressed. D-NG-nitro arginine methyl ester was ineffective in preventing these neurochemical changes, thus indicating the stereoselective nature of the inhibition by L-NG-nitro arginine methyl ester. Furthermore, L-NG-nitro arginine methyl ester pre-treatment likewise prevented increases in both NO2 and NO3 levels. When rats were exposed to 80% nitrous oxide in oxygen, there was loss of the righting reflex but no change in hippocampal NOx levels. These findings indicate that isoflurane increases production of hippocampal NO and that this may be pertinent to general anaesthetic drug effects.