SummaryThe risk of accidental over-dosing of obese children poses challenges to anaesthetists during dose calculations for drugs with serious side-effects, such as analgesics. For many drugs, dosing scalars such as ideal body weight and lean body mass are recommended instead of total body weight during weight-based dose calculations. However, the complex current methods of obtaining these dosing scalars are impractical in the peri-operative setting. Arbitrary dose adjustments and guesswork are, unfortunately, tempting solutions for the time-pressured anaesthetist. The study's aim was to develop and validate an accurate, convenient alternative. A nomogram was created and its performance compared with the standard calculation method by volunteers using measurements from 108 obese children. The nomogram was as accurate (bias 0.12 kg vs À0.41 kg, respectively, p = 0.4), faster (mean (SD) time taken 2.8 (1.0) min (vs 3.3 (0.9) min respectively, p = 0.003) and less likely to result in mistakes (significant errors 3% vs 19%, respectively, p = 0.001). We present a system that simplifies estimation of ideal body weight and lean body mass in obese children, providing foundations for safer drug dose calculation.

The utilisation of the pre-operative ECG inpatients undergoing routine surgery was investigated in 354 adult patients over a 2-week period. Sixty-four percent of patients had an ECG pre-operatively. An ECG was not performed in 17% of patients who, current hospital policy suggests, should have had one. In contrast, an ECG was performed in 33% ofpatients who, hospital policy suggests, have no need of one (all of which were normal), which represented 18% of the total number of pre-operative ECGs performed.In 62% of patients with known cardiac disease, and 44% of patients with strong risk factors for ischaemic heart disease (in the absence of known disease) the ECG was abnormal. This compares with only 7% of patients aged over 50 with no risk factors in whom the ECG was abnormal. These findings suggest that there is room for improvement in the utilisation of the pre-operative ECG, which may have cost implications. Key wordsMonitoring; electrocardiography.The pre-operative ECG is a quick, safe test performed routinely in patients with the aim of detecting pre-existing cardiovascular disease, which, if abnormal is associated with increased postoperative risk [I, 21. It may also be of value as a baseline reading in patients with known cardiac disease or cardiac risk factors to assess the significance of any postoperative ECG abnormalities. However, the accumulated cost of the test is high and, particularly in the present atmosphere of cost containment, the use of such tests needs to be reviewed frequently to ensure that they are being used in appropriate patients.Current guidelines within our hospital suggest that a pre-operative ECG should be performed in all patients who have either known cardiac disease, are at risk of cardiac disease, or who are aged over 50 years.As part of a larger survey of the pre-operative cardiovascular status of the surgical population in our hospital, we have investigated the practice of requesting pre-operative ECGs and the incidence of abnormalities. MethodsThe survey was conducted over a 2-week period in May 1993 in all patients aged over 16 years undergoing anaesthesia in the following specialties: general surgery, urology, ophthalmic surgery, ENT surgery, neurosurgery, dental surgery and vascular surgery. Patients having emergency surgery were not included.Information was collected about each patient presenting for surgery. A careful pre-operative medical history, with particular emphasis on the cardiovascular system, was taken from each patient. Patients with known cardiac disease were defined as patients with ischaemic heart disease (previous myocardial infarction or angina) or valvular heart disease. Patients considered to be at risk of ischaemic heart disease were patients who had hypertension, peripheral vascular disease, diabetes, or a past history of cardiac failure or cerebrovascular event in the absence of known cardiac disease.Patients were divided into four groups based upon their pre-operative history: group 1 = patients with known cardiac disease; group 2 = patients at ris...

We have studied the incidence and duration of perioperative myocardial ischaemia using ambulatory ECG monitoring in 100 patients undergoing transurethral surgery, who were allocated randomly to receive either general or spinal anaesthesia. The overall incidence of myocardial ischaemia increased from 18% to 26% between the preoperative and postoperative periods. Patients with ischaemic heart disease had a significantly greater incidence of myocardial ischaemia after operation than patients without known ischaemic heart disease (P < 0.05). There was an increase in both the incidence and duration of myocardial ischaemia after operation with both anaesthetic techniques, but no significant difference between the two.

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