Day-night pattern in accidental exposures to blood-borne pathogens among medical students and residents.

The purpose of this study was to determine whether the occurrence of accidental blood-borne pathogen exposure incidents in medical students and residents in training varies during the 24 h. A retrospective review of reported exposures was conducted in a large urban teaching institution--the University of Texas Health Science Center in Houston--between November 1993 and July 1998. Professional level (year of student or level of resident), time of exposure, means/route of exposure (needle stick, laceration, or splash), and type of medical service were recorded. Analysis of the clock time of the 745 reported blood-borne pathogen exposures showed they occurred more frequently during the day than night. Over the nearly 5-year span, 531 incidents took place between 06:00 and 17:59 in comparison to only 214 between 18:00 and 05:59. To account for the day-night difference in medical student and resident hospital staffing, the data were reexpressed as exposure rates, that is, in terms of the number of events per hour per 1000 medical students and residents. Based on the total number of reported exposures over the almost 5-year span of data collection, the average rate was 40 accidents per hour per 1000 doctors in training during the 12 h daytime span (6:00-17:59). It was 50% greater at night (18:00-05:59), with 60 incidents per hour per 1000 doctors in training. The day-night difference in rate of exposures was statistically significant (p < .04). The relative risk ratio for residents and students when working during the day shift compared to working the night shift was 0.67. This means that doctors in training are at a 1.50 higher risk of sustaining a blood-borne pathogen exposure when working nights than when working days.

Intestinal parasitosis in an urban pediatric clinic population.

Three hundred twenty-one pediatric patients were prospectively screened for intestinal parasites. Of the stool specimens, 49.5% were positive for ova or parasites. Positive stool specimens were significantly correlated with recent travel to Mexico by the patient or a household member. The incidence rate for Giardia lamblia was 20%, and it was 5% for both Ascaris and Trichuris. Hymenolepis nana was the fourth most common parasite, with a rate of 4%. No identifiable clinical, laboratory, or other demographic predictors of parasitic infestation were found. Giardia seems to be rapidly increasing in prevalence and may be the most frequently isolated parasite in the southern United States.

Hazards of battery ingestion.

A 12-year-old boy ingested a mercury battery from a watch as a part of an alleged poisoning attempt by an uncle. The battery apparently ruptured spontaneously in the child's stomach less than 36 hours after ingestion. At surgery one battery terminal was found embedded in gastric mucosa thought to be progressing toward gastric perforation. The unique complications of battery ingestion, such as gastrointestinal perforation and possible mercury poisoning, are reviewed. A strong recommendation for immediate endoscopic or surgical removal of ingested batteries is made. Parental education along with preventive measures by manufacturers such as package warnings, specific labeling of battery contents on each package, and "childproofing" of battery-containing products is stressed.