The accuracy of standardized patient presentation.

The accuracy of standardized patient clinical problem presentation was evaluated by videotape rating of a random sample of 839 student-patient encounters, representing 88 patients, 27 cases and two university test sites. Patient-student encounters were sampled from a collaborative inter-university final-year clinical examination of fourth-year medical students which was conducted at the University of Manitoba and Southern Illinois University in 1987 and 1988. The accuracy, replicability and portability of standardized patient cases were evaluated. The average accuracy of patient presentation was 90.2% in 1987 and 93.4% in 1988. Perfect accuracy scores were obtained by 15 patients; however, 11 patients had average scores below 80% with the accuracy of presentation in some encounters being as low as 30%. There were significant differences in the accuracy score achieved by patients trained together for the same case in 6 of 35 possible comparisons. There was also a systematic trend for patients trained at Southern Illinois to be more accurate in their presentation than patients trained at the University of Manitoba. These differences were significant in 5 of the 15 cases used in the examination.

Myocardial failure and shock in iron poisoning.

Shock is a well-known complication of iron poisoning. Its aetiology is multifactorial with hypovolaemia due to gastrointestinal blood loss and myocardial depression due to systemic acidosis contributing to its genesis. Primary myocardial dysfunction has not been considered to play a role. Our clinical experiences and autopsy findings in three fatal cases of iron poisoning support myocardial dysfunction and damage as contributing factors to their cardiovascular collapse. The three patients, all female, were 3 1/2, 16 and 28-years-old. Onset of shock occurred at 1, 2 and 5 days post-ingestion. There was no response to vigorous fluid replacement therapy and aggressive catecholamine infusions. Central venous pressures were elevated. Microscopic examination of postmortem tissue showed myocardial damage and the presence of stainable iron. It is speculated that the myocardial depression is mediated by lipid peroxidation of myocyte organelle membranes due to iron catalysed free radical generation. The presence of myocardial dysfunction has therapeutic implications. Patients with severe iron poisoning require early and serial measurements of arterial blood pressure, central venous pressure and cardiac output. If primary myocardial dysfunction is documented then fluid replacement, inotropic support and afterload reduction should be considered.