Right lung ventilation in a porcine open-chest shock model.

OBJECTIVE: To determine the effect of selective right lung ventilation on gas exchange and hemodynamics when compared with bilateral lung ventilation in a porcine open-chest shock model. METHODS: A randomized, controlled laboratory investigation was performed using a static hemorrhagic shock model in 12 adult swine undergoing thoracotomy. The animals were subjected to a fixed 40% circulating blood volume hemorrhage over 20 minutes. Each animal was then assigned to either a tracheal (control) or a right mainstem (experimental) intubation group. Minute ventilation was held constant in both groups and tidal volumes were decreased by 33% in the right mainstem intubation group. Following intubation and left lateral thoracotomy, another 20% fixed-volume hemorrhage was instituted simultaneously with IV crystalloid and whole blood resuscitation for both groups over 30 minutes. Heart rate, blood pressure, and arterial blood gases were measured at 5-minute intervals. RESULTS: There was no significant difference between the control and experimental groups for any of the measured variables, including mean arterial pressure, pH, partial arterial pressure of CO2 (PaCO2), and PaO2, over time. All animals survived the study protocol. CONCLUSION: Selective right lung ventilation has no detrimental effect on gas exchange or hemodynamics when compared with standard bilateral lung ventilation in a porcine open-chest shock model.

Pregnancy in the emergency department: risk factors and prevalence among all women.

STUDY OBJECTIVE: To determine the prevalence of unrecognized pregnancy in the emergency department and to ascertain if patient history can effectively detect unrecognized pregnancies. DESIGN: Prospective study. SETTING: Urban ED with annual census of 40,000. PARTICIPANTS: One hundred ninety-one consecutive women meeting inclusion criteria. INTERVENTIONS: All participants completed a menstrual/sexual history questionnaire and had a urine pregnancy test. RESULTS: Overall, we found a 6.3% prevalence of unrecognized pregnancy. Women with abdominal/pelvic complaints had a 13% prevalence; those with other complaints had a 2.5% prevalence. Two historical risk factors, the patient's suspicion that she might be pregnant and an abnormal last menstrual period, had a statistically significant correlation with unrecognized pregnancy. A third risk factor, the presence of abdominal/pelvic complaints, nearly achieved statistical significance. These risk factors detected all unrecognized pregnancies with a sensitivity of 100% and a specificity of 54%. CONCLUSION: The prevalence of unrecognized pregnancy in our ED was 6.3%. Historical risk factors detected all of them.