The difference between the mean operative delays in the two groups was therefore 43 hours (95% confidence interval 41-35 to 44-45 h; t=6 0 143 df; p

All hepatitis B carriers who were HBeAg-positive had high titres of HBsAg; this could not be used as a reliable indicator of the presence of HBeAg, however, because some of the carriers with anti-HBe also had high HBsAg titres. Generally it has been found that many HBsAg carriers have neither HBeAg nor anti-HBe, which reflects the relative insensitivity of immunodiffusion-for example, in our study 2900 of the carriers were e-negative by this test. This number of unclassifiable carriers has made it difficult to evaluate the relation between HBeAg and raised liver enzyme concentrations reported by Maynard et al'6 and Polesky and Hanson."7 By using the more sensitive e-RIA in addition to immunodiffusion we could confirm their observations and show a more precise relation between the presence of HBeAg and raised enzyme concentrations.In acute hepatitis B infections serum liver enzyme concentrations are generally much higher than those in carriers and HBeAg is only transiently present. In chronic asymptomatic carriers persistently, though modestly, raised liver enzyme concentrations appear to be a useful indicator of the presence of e antigen and thus of probable infectivity. Indeed, it is interesting to compare the accuracy of using either immunodiffusion or raised enzyme concentrations to identify the HBeAgpositive carriers. Immunodiffusion identified 12 of the 14 HBeAg-positive sera, whereas 13 were identified by finding raised enzyme concentrations, though at the cost of three anti-HBe sera being incorrectly classified.Testing for the presence of HBeAg is practicable only for specialised laboratories; on the other hand, estimating liver enzyme concentrations is a routine determination in any general hospital. We consider that when assessing the potential infectivity of an indigenous HBsAg carrier in the UK estimating liver enzyme concentrations is a simple and accurate alternative to the specific tests for HBeAg. Haemodynamic effects of buprenorphine after heart surgery Medical_Journal, 1978, 2, 1602-1603 Summary and conclusions The effect of buprenorphine on the cardiovascular system was examined in 11 patients during the period of reduced cardiac reserve after open-heart surgery. Within 10 minutes of giving the full analgesic dose (5 ,_tg/kg) intravenously the mean heart rate had fallen significantly by six beats,'min. Although in two patients the mean arterial pressure fell by 24 mm Hg, there was no overall change in mean arterial pressure, carciiac output, or peripheral resistance. In a further six patients buprenorphine was used successfully as the sole analgesic after open-heart surgery.

1 The treatment of pain of cardiac origin requires a knowledge of the haemodynamic action of the analgesic agents used. 2 The haemodynamic effects of morphine, diamorphine, pavaveretum, pethidine and pentazocine are reviewed. 3 Clinical experience with the new antagonist analgesic buprenorphine is reported. 4 These studies indicate that buprenorphine may be the agent of choice for the relief of severe pain in patients with unstable circulation.

The haemodynamic effects of a continuous intravenous infusion of salbutamol (15 to 30 'g/min) and nitroprusside (50 to 100 tug/min) were compared in 9 patients after cardiac surgical operations. The mean falls in left atrial pressure and systemic vascular resistance were similar with the two drugs but salbutamol caused a greater increase in heart rate, maximum acceleration of aortic bloodflow, and maximum rate of change of left ventricular power. Because these differences would cause greater myocardial oxygen consumption with salbutamol and because the infusion of salbutamol is less easily controlled, nitroprusside is the preferred drug after cardiac operations.Drugs that cause vasodilatation and consequently a reduction in systemic vascular impedance (left ventricular afterload) have recently been advocated in a variety of circumstances in which cardiac function is abnormal. Advantageous effects have been reported in patients with acute myocardial infarction (Chatterjee et al., 1973), chronic ischaemic heart disease (Miller et al., 1975), refractory heart failure (Guiha et al., 1974), mitral regurgitation and stenosis (Goodman et al., 1974;Bolen et al., 1975), and cardiomyopathy (Rossen et al., 1976 The present study was undertaken to measure the haemodynamic changes during a continuous intravenous infusion of salbutamol in patients soon after cardiac operations. A comparison was made with the effects of an infusion of nitroprusside because this drug has previously been recommended in similar circumstances (Stinson et al., 1975). MethodsNine patients (7 male, 2 female; age range 36 to 64 years, mean 51 years) were studied. Five had aortocoronary bypass grafts inserted and 2 had had aortic and 2 mitral valve replacement. The patients were unselected consecutive surgical candidates in whom preoperative catheterisation had excluded left ventricular dyskinesia or valve disease other than that for which the operation was being performed. The exact nature of the investigation was explained to the patients in order to obtain informed consent.The study began 24 to 36 hours after operation, at a time when the patients could be maintained for several hours in quiet undisturbed circumstances. During this period no additional drugs were given.One patient was receiving an inotropic agent (iso.

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