Sterility and performance of open and closed extracorporeal circuits after long-term dry-wet setups.

BACKGROUND: The timeframe for safely using previously setup dry, crystalloid, and blood-primed extracorporeal circuits has long been debated. This study was undertaken to determine a safe deviation from standardized recommendations. METHODS: Open (cardiopulmonary bypass) circuits and closed extracorporeal membrane oxygenation circuits were setup dry for up to 60 days and wet primed for up to 6 weeks with one control inoculated with Escherichia coli. Open circuits were cultured daily, closed circuits weekly. Circuits were primed with blood, albumin, heparin, NaHCO3, and CaCl2. Baseline pCO2, pO2, hemoglobin, lactate dehydrogenase, and plasma free hemoglobin were measured. Circuits were recirculated at a blood flow of 6 Liters/minute with a sweep gas of 1 Liter/minute at 100% FiO2 for 1 minute. Post oxygenator blood gases were collected at 8-, 16-, and 24-hour intervals. RESULTS: There was no observed compromise to the sterility of the circuits and no clinically significant gas exchange abnormalities observed over the duration of the study period. Statistical significance (p < 0.01) was seen in free hemoglobin and lactate dehydrogenase levels, most significant in between the 16- and 24-hour time point in the closed systems intentionally inoculated with E. coli. CONCLUSION: Open and closed circuits can be safely setup dry for up to 60 days. Open, wet-primed circuits can be used safely up to 5 days. Closed, wet-primed circuits can be used safely up to 6 weeks. Blood-primed circuits can be safely run up to 16 hours prior to patient use but should be validated in a randomized clinical study.

Antibiotic prophylaxis practices in dentistry: a survey of dentists and physicians.

BACKGROUND: A survey was conducted to determine prescribing practices of general dental and medical practitioners regarding the use of antibiotics for prophylaxis. MATERIALS AND METHODS: A questionnaire with an accompanying letter was designed to investigate prescribing practices of general dentists and physicians. The survey encompassed demographic data, mechanisms to keep current with prophylactic practice, first- and second-line drugs prescribed with doses and directions, applicable medical conditions and dental procedures warranting antibiotic prophylaxis. Names were chosen randomly from provincial lists and ethics approval was granted. Responses were compared with 1997 American Heart Association (AHA) guidelines. RESULTS: In all, 1,500 surveys were sent to each group, with a response rate of 32% of dentists and 17% of physicians. There was a significant difference (p < 0.05) between dentists (95%) and physicians (71%) in selecting the correct first-line antibiotic, amoxicillin, and in choosing the correct dose of amoxicillin (i.e., 2 g, 1 hour before treatment): 88% of dentists and 48% of physicians (p < 0.05). Appropriate second-line drugs were correctly selected by 84% of dentists and 67% of physicians--a significant difference (p < 0.05)--with clindamycin chosen most often (82% and 49%, respectively). Over 90% of respondents in both professions correctly identified conditions, such as prosthetic heart valve and endocarditis, requiring antibiotic prophylaxis. CONCLUSIONS: Clinicians are not always aware of current clinical guidelines, and dentists and physicians exhibit different patterns regarding antibiotic prescribing. Dentists are more familiar than physicians with current protocols of the AHA.