Gum elastic bougie, capnography and apnoeic oxygenation.

BACKGROUND AND AIM: This study assessed the accuracy of using capnography with a modified, hollow gum elastic bougie in predicting tracheal intubation, and its effectiveness as a method of apnoeic oxygenation. METHODS: Patients were randomly allocated to having the gum elastic bougie inserted, under anaesthesia, in the trachea or the oesophagus. End-tidal carbon dioxide measurements were made at 10 and 20 s. The position of the gum elastic bougie was correctly predicted in 89.2% of patients. We tested the apnoeic oxygenation on an anaesthetic simulator model, which is housed in the Scottish Anaesthesia Simulator Centre, Stirling, UK. RESULTS: The time taken for the oxygen saturation to fall to 90% was significantly prolonged when the gum elastic bougie was used for apnoeic oxygenation. CONCLUSION: The modification of the gum elastic bougie allows a more objective assessment of correct placement than the previous tactile method. The current design of bougie is unsuitable but can be modified.

Patients' desire for information about anaesthesia: change in Scottish attitudes over five years.

In 1989, 49 general surgical in-patients in our hospital completed a preoperative questionnaire concerning their desire for information about anaesthesia. We have now repeated the study.

Anaesthesia for thoracoscopic pleurectomy and ligation of bullae.

A patient is described who, despite severe pre-operative respiratory disability, had her persistent pneumothorax successfully managed by thoracoscopic pleurectomy. The technique causes considerably less pain and interference with respiratory function postoperatively than does conventional thoracotomy. Potential anaesthetic problems arise because of the necessity of insufflating carbon dioxide at pressures of up to 1 kPa to maintain a pneumothorax during surgery.

Patients' desire for information about anaesthesia. Scottish and Canadian attitudes.

Patients in Canada and Scotland were asked to complete a pre-operative questionnaire examining their desire for information relating to anaesthesia. In both Canada and Scotland, patients under the age of 50 years had a greater wish to receive information than those who were older (p less than 0.0001). In Canada, female patients were found to be more keen to receive pre-operative information than males of the same age group (p less than 0.05). The priority given to individual pieces of information was remarkably similar in both countries. Details of dangerous complications of anaesthesia and surgery were consistently rated of low priority, with high priority going to postoperative landmarks such as eating and drinking. Both countries rated meeting the anaesthetist before surgery as the highest priority of all.

General anaesthesia and undrained pneumothorax. The use of a computer-controlled propofol infusion.

A patient who required pleurectomy had a 30% pneumothorax when she was presented for anaesthesia. She had refused to have this drained, and it had not responded to conservative management. She was anaesthetised using a computer-controlled propofol infusion system, without the use of nitrous oxide, and a chest drain was inserted before the institution of positive pressure ventilation. This technique reduces the hazards associated with general anaesthesia in the presence of an undrained pneumothorax. It may be a safe alternative method of induction of anaesthesia in other conditions in which positive pressure ventilation must be avoided, such as bronchopleural fistula.

Preoperative piroxicam for postoperative analgesia in dental surgery.

Fifty patients were allocated randomly to receive placebo or piroxicam 40 mg, 2.5 h before surgical removal of lower third molars under general anaesthesia. A significantly greater number of patients in the piroxicam group did not require opioid analgesia after operation (P less than 0.05). The piroxicam group also required fewer doses of paracetamol in the first 24 h after recovery from anaesthesia (P less than 0.05), and the time from recovery to first postoperative analgesia was longer in those patients who had received piroxicam (P less than 0.05). Piroxicam did not significantly prolong the duration of recovery from anaesthesia.

Oral contraception and post-operative thromboembolism: an epidemiological review.

It has been stated that oestrogen-containing oral contraceptive medication should be discontinued one month prior to surgery, to avoid an increased incidence of post-operative thromboembolism. Others have suggested that the risk of post-operative morbidity is low compared with the risk of pre-operative pregnancy, and that in most cases no such action should be taken. The evidence from clinical investigation is reviewed, with particular reference to study design. It is found that all studies so far conducted are subject to sources of bias or confounding which render their results inconclusive. There is a need for a randomised control trial comparing the effects of discontinuing or continuing oral contraception prior to surgery. Meanwhile, with a post-operative risk inferred but not conclusively demonstrated, if oral contraception is to be withdrawn prior to surgery, great care must be taken to reduce the risk of ensuing pregnancy to as near zero as possible.

PIP: The debate on discontinuation of the oral contraceptive (OC) pill prior to major surgery because of the risk of preoperation pregnancy and increase in postoperative mortality is reviewed in light of 6 studies published on this issue. OC use has been associated with the risk of thromboembolism and the postoperative onset of deep venous thrombosis (DVT) is equally well-known. A study by Vessey in 1970 found an almost 4 times higher risk for OC users to develop DVT after an operation, however, multiple biases could be ascribed to the study design. A U.S. questionnaire study following up released patients received only a 60% response rate, the subjects controls ratio was distorted, and the almost 3 times higher risk finding was highly suspect. 2 other studies showing a 19% and 10.5% DVT rate for OC users after surgery had even more significant omissions regarding age, weight, and pelvic disease. In a study by Gallus examining 221 women aged 18-49 after emergency surgery, only 1 control had DVT, however, controls tended to be older, heavier, and had twice as many varices. The Oxford/Family Planning Association contraceptive study indicated a 0.96% incidence of thromboembolism for OC users vs. 0.5% for nonusers, which is not statistically significant. Thus, the investigation of postoperative thromboembolism allegedly caused by OC use is wrought with difficulties owing to the multiplicity of risk factors, and before discontinuation is advised these variables have to be weighed and an alternative has to be offered.

Incidence of arrhythmias in dental anaesthesia: a cross-over comparison of halothane and isoflurane.

Fifty patients received halothane anaesthesia during the surgical removal of 3rd molars from one side of the mouth and isoflurane during extractions on the other. Degree of surgical difficulty was matched, and end-tidal PCO2 did not differ significantly between sides. A significantly higher incidence of arrhythmias occurred during halothane, compared with isoflurane, anaesthesia. This difference occurred primarily when halothane was given for the first operated side. A clinically important feature of the stability of cardiac rhythm during isoflurane anaesthesia was demonstrated--when frequent ectopic beats occur during halothane anaesthesia, a significant decrease in the rate of premature contractions occurs within 3 min of discontinuing halothane and introducing isoflurane.

The severance of epidural catheters.

Four groups of Portex Minipack epidural sets were tested to measure the force required to sever the catheter on the needle bevel. The 18-gauge radio-opaque catheter was found to sever at a significantly lower applied force and to stretch significantly less before breaking than the 18-gauge clear catheter or either of the 16-gauge catheters. The other catheters tested had breaking strains of between 10-20 Newtons (1-2 kg force) and stretched by more than 30% of their lengths before breaking. It is suggested that these other catheters may therefore be a preferable alternative to the 18-gauge radio-opaque.