SummaryFifty patients scheduled for surgery under lumbar epidural anaesthesia were included in a study to evaluate the possibility of localising the epidural space solely by means of an acoustic signal. With an experimental set-up, the pressure generated during the epidural puncture procedure was translated into a corresponding acoustic signal. One anaesthetist held the epidural needle with both hands and detected the epidural space by means of this acoustic signal. At the same time, a second anaesthetist applied the loss of resistance technique and functioned as control. In all patients the epidural space was located with the acoustic signal. This was confirmed by conventional loss of resistance in 49 (98%) of the patients; in one patient (2%) it was not. We conclude that it is possible to locate the epidural space using an acoustic signal alone.

SummaryThe insertion of an epidural catheter for labour analgesia may be challenging. This observational study compared pressures during insertion of an epidural catheter in pregnant (n = 35) and non-pregnant (n = 10) women, using an acoustic device for locating the epidural space that also records and stores pressure data during the procedure. In both groups, we compared the maximum pressure just before loss of resistance, the pressure in the epidural space and the pressure in the inserted epidural catheter. Maximum pressure just before loss of resistance in the pregnant women was significantly lower compared with the non-pregnant women. Pressures in the epidural space and with the disposable tubing connected to the inserted epidural catheter were greater in pregnant women than in non-pregnant women. The results support the hypothesis that physiological changes in the third trimester of pregnancy are the reason why epidural catheters are more difficult to insert in women in labour.

SummaryA postoperative questionnaire was used in 129 patients who had undergone a wide range of surgical procedures in order to investigate their personal experience of anaesthesia. The most frequent complaints were offeeling cold on waking up, sore throat, vomiting and muscle pains, all of which are capable of reduction by a change in anaesthetic technique. The total number of patients who had one or more complaints was 107 (82.9%). More than a third ofthe patients were afraid ofthe anaesthetic, as distinct from the operation. Most had received a pre-operative visit from the anaesthetist which was greatly appreciated. A few patients believed they could have been better informed of possible sequelae. More than 30% were not visited by the surgeon before the operation. A routine postoperative interview, using a preformulated questionnaire, is a good way to assess and maintain a high quality of anaesthesia. Key wordsAnaesthesia; audits.It is essential for every clinician to assess his (or her) results. This is relatively easy in the majority of specialties since a limited number of criteria can be used, but this is not the case after an anaesthetic, where most criteria are subjective. Nowadays the patient demands more from the anaesthetist than the ability to wake up. Four articles appeared between 1978 and 1985, following an Editorial in Anaesthesia in 1976,' in which the results of the use of a postoperative questionnaire were rep~rted."~ We have used a version of the above method adapted to our own hospital and with certain aspects amplified.The aims of our investigation were not only to record any anaesthetic complications or sequelae, but also to determine patient expectations of anaesthesia, their concept of the role of anaesthetists and the service they provide, and the desirability of pre-and postoperative visits by the anaesthetist to the patient. Patients and methodsOne hundred and twenty-nine patients were interviewed out of 143 who underwent general, plastic, orthopaedic, neurological, urological, ENT, vascular or gynaecological surgery during a 2-week period in July 1988.Patients under 14 years of age and those who had undergone brain surgery were excluded from the enquiry. Emergency surgery was excluded because of variability in the pre-operative period, and also cardiac operations because high doses of opioids and low doses of anaesthetic drugs are used, with an increased risk of awareness. The patients were interviewed 1-3 days after operation using a preformulated questionnaire. All interviews were carried out by the same person, who was not an anaesthetist, to eliminate bias. The data were processed on computer using the LOTUS program. Statistical analysis used the SPSSsystem for the Chi-square test and the Yates' continuity correction. Statistical significance was taken as p < 0.05. ResultsOnly 129 (90.2%) of the 143 patients could be interviewed because eight bad already gone home, three were too ill, one was deaf, one could not be located and one did not speak the language. Forty-five per cent ...