Dipyridamole-thallium myocardial scanning in the preoperative assessment of patients undergoing abdominal aortic aneurysmectomy.

Dipyridamole thallium scanning (DTS) is an imaging technique with good sensitivity for coronary artery disease (CAD). The purpose of this study was to compare the haemodynamic courses and the correlation between pulmonary capillary wedge pressure (PCWP) and central venous pressure (CVP) in patients with normal DTS (Group 1: n = 12) with those whose scans demonstrated CAD (Group 2: n = 11). Haemodynamic profiles were obtained prior to anaesthesia and at several times during surgery. The haemodynamic courses in both groups were similar with significant decreases in cardiac index, stroke index, and left ventricular stroke work index during aortic cross-clamping compared with values prior to anaesthesia. There were no significant changes in PCWP and CVP throughout the study. The correlations between PCWP and CVP were significant in both groups as were the correlations between the changes in PCWP and the changes in CVP observed at the time of cross-clamping. These correlations all had large standard errors of the estimate, however, making it impossible to predict the PCWP from the CVP with precision. It is concluded that, in a limited study population, an abnormal DTS did not identify patients in whom the PCWP and CVP correlated poorly during abdominal aortic aneurysmectomy.

Prevalence of hepatitis B in anaesthesia personnel.

Hepatitis B virus (HBV) infection, an occupational risk to anaesthetists, varies widely in incidence throughout the world. This study was undertaken to define the prevalence of previous HBV infection in anaesthesia personnel in the teaching hospitals of metropolitan Vancouver. Participants donated a blood sample and completed a questionnaire. Overall participation rate was 90.4 per cent. No participants were HBV carriers. Ten of 83 anaesthetists (12 per cent) had antibodies to HBV while all anaesthesia residents were seronegative. Anaesthetists with HBV antibodies tended to be either older or foreign born. Standard precautions taken by anaesthetists such as use of preoperative questioning of a patient's hepatitis status or the use of gloves when handling body fluids of a suspected or proven HBV carrier could not be shown to affect this seropositivity rate. This study, consistent with others, suggests that anaesthetists are at risk for acquiring HBV infection from occupational exposure. This risk appears to be somewhat less than that for surgeons, dentists, and staff of dialysis and urban emergency units.

Failure of nimodipine to reverse acute experimental spinal cord injury.

The calcium-channel blocking agent, nimodipine, was administered to cats for 5 days after acute experimental SCI. Six weeks after injury, no significant differences in neurologic recovery or white matter tissue preservation at the injury site were found between treated and control animals.

Therapeutic trial of hypercarbia and hypocarbia in acute experimental spinal cord injury.

Hypocarbia, normocarbia, or hypercarbia was maintained for an 8-hour period beginning 30 minutes after acute threshold spinal cord injuries in cats. No statistically significant differences in neurological recovery or histologically assessed tissue preservation were found among the three groups of animals 6 weeks after injury. No animal recovered the ability to walk. It is concluded that maintenance of hypercarbia or hypocarbia during the early postinjury period is no more therapeutic than maintenance of normocarbia. Mortality rates and tissue preservation data suggest, however, that postinjury hypocarbia may be less damaging than hypercarbia.

Failure of tetracaine to reverse spinal cord injury in the cat.

Beginning 30 minutes after acute spinal cord injury, cats were treated by the administration of continuous spinal anesthesia for 8 hours. This was achieved by the intermittent injection of hyperbaric tetracaine into the subarachnoid space at the site of injury via an indwelling catheter. There were no significant differences in functional recovery or histologically assessed tissue preservation between treated cats and concurrently managed control animals. The indwelling subarachnoid catheter used for drug administration was found to have no significant effect on the spinal cord injury.