Pyrexia after total knee replacement. A cause for concern?

Ninety patients who had undergone 92 total knee replacements were reviewed to determine predictors of postoperative pyrexia and to evaluate the relative value of septic screening in this group of patients. Postoperative pyrexia was defined as an axillary temperature greater than 37 degrees C (98.4 degrees F) on any or all of the 5 days after surgery. All of the patients in this series developed a postoperative pyrexia after knee arthroplasty. None of 16 patients (17% of arthroplasties) with a temperature of 39 degrees C (102 degrees F) or greater had evidence of infection. None of the 4 patients with urinary tract infections developed a pyrexia exceeding 38 degrees C (101 degrees F). At a minimum of 2 years' follow-up, none of the 90 patients had developed an infected arthroplasty. Logistic regression analysis showed that the risk of becoming significantly febrile (temperature > 39 degrees C) doubled for every unit drop in hematocrit and increased fourfold for each unit of blood transfused after surgery. Perioperative blood loss and pyrexia were correlated, but the correlation was not statistically significant. The duration of procedure, tourniquet time, and patient age or sex were not associated with risk of pyrexia. In this series, there was no association between a pyrexia greater than 37 degrees C, septic screening, and the presence of an infective focus. Early postoperative pyrexia after arthroplasty is a normal physiological response, and a significant pyrexia can be predicted by a drop in hematocrit and/or after postoperative transfusion. Pyrexia in the early postoperative period following total knee arthroplasty warrants detailed laboratory and radiographic investigation only in the presence of positive physical findings.

Age-dependent inhibition of suckling by cholecystokinin.

The effects of exogenous cholecystokinin (10--40 U/kg body wt) on neonatal rat suckling were studied in 5-, 10-, 15-, and 20-day-old rats that were equipped with tongue cannulas. Milk (0.1 ml over 10 s) was delivered through the tongue cannula once every minute, providing a rat was still suckling. Cholecystokinin, a well-established inhibitor of adult rat feeding, did not reduce milk intake volume of 5- and 10-day-old rats. It did, however, depress milk intake of 15- and especially of 20-day-old rats. Despite its effect on milk intake, cholecystokinin never lengthened the latency to attach to the nipple and, paradoxically, reduced it on certain occasions. The implications of these findings for the events controlling various aspects of suckling behavior throughout the course of the nursing-suckling period in rats and for the mechanism of action of cholecystokinin are discussed.

Federal licensure as consumer protection.

In the continuing debate over licensure for radiologic technologists, more concern needs to be directed toward the patient as the unwary consumer. Radiology patients can only presume that maximum effort is being taken to minimize x-ray exposure. Unfortunately, the patient has little control in guaranteeing that premise.