Randomized, prospective trial of bilevel versus continuous positive airway pressure in acute pulmonary edema.

OBJECTIVE: To evaluate whether bilevel positive airway pressure, by actively assisting inhalation, more rapidly improves ventilation, acidemia, and dyspnea than continuous positive airway pressure (CPAP) in patients with acute pulmonary edema. DESIGN: Randomized, controlled, double-blind trial. SETTING: Emergency department in a university hospital. PATIENTS: Twenty-seven patients, presenting with acute pulmonary edema, characterized by dyspnea, tachypnea, tachycardia, accessory muscle use, bilateral rales, and typical findings of congestion on a chest radiograph. INTERVENTIONS: In addition to standard therapy, 13 patients were randomized to receive nasal CPAP (10 cm H2O), and 14 patients were randomized to receive nasal bilevel positive airway pressure (inspiratory and expiratory positive airway pressures of 15 and 5 cm H2O, respectively) in the spontaneous/timed mode that combines patient flow-triggering and backup time-triggering. MEASUREMENTS AND MAIN RESULTS: After 30 mins, significant reductions in breathing frequency (32 +/- 4 to 26 +/- 5 breaths/min), heart rate (110 +/- 21 to 97 +/- 20 beats/min), blood pressure (mean 117 +/- 28 to 92 +/- 18 mm Hg), and Paco2 (56 +/- 15 to 43 +/- 9 torr [7.5 +/- 2 to 5.7 +/- 1.2 kPa]) were observed in the bilevel positive airway pressure group, as were significant improvements in arterial pH and dyspnea scores (p < .05 for all of these parameters). Only breathing frequency improved significantly in the CPAP group (32 +/- 4 to 28 +/- 5 breaths/min, p < .05). At 30 mins; the bilevel positive airway pressure group had greater reductions in Paco2 (p = .057), systolic blood pressure (p = .005), and mean arterial pressure (p = .03) than the CPAP group. The myocardial infarction rate was higher in the bilevel positive airway pressure group (71%) compared with both the CPAP group (31%) and historically matched controls (38%) (p = .05). Duration of ventilator use, intensive care unit and hospital stays, and intubation and mortality rates were similar between the two groups. CONCLUSIONS: Bilevel positive airway pressure improves ventilation and vital signs more rapidly than CPAP in patients with acute pulmonary edema. The higher rate of myocardial infarctions associated with the use of bilevel positive airway pressure highlights the need for further studies to clarify its effects on hemodynamics and infarction rates, and to determine optimal pressure settings.

Use of urinary gram stain for detection of urinary tract infection in infants.

STUDY OBJECTIVE: To determine whether Gram stain of urine is more sensitive than urinalysis in detecting urinary tract infection in infants. DESIGN: Prospective series. SETTING: Urban teaching hospital emergency department. PARTICIPANTS: Two hundred seven infants 6 months old or less, from whom a catheterized or suprapubically aspirated urine specimen was obtained for culture. INTERVENTIONS: Urinary Gram stain, culture, and urinalysis were performed. With culture results as the validating standard, the Gram stain sensitivity, specificity, and predictive values were compared with urinalysis, including leukocyte esterase, nitrite, pyuria, and bacteriuria. RESULTS: The prevalence of positive cultures was 8.7% (18 of 207). Gram stain had higher sensitivity than overall urinalysis (94% versus 67%, P < .05), higher specificity (92% versus 79%, P < .05), and higher positive predictive value (53% versus 23%, P < .05). CONCLUSION: Urinary Gram stain appears to be more reliable than urinalysis in detecting urinary tract infection in young infants.

Indium-111 antimyosin antibody imaging: a promising new technique in the diagnosis of M.I.

Extensive clinical research has demonstrated that the administration of indium-111 antimyosin antibodies is useful in the diagnosis of acute myocardial infarction. It is specific for acute myocardial necrosis, as opposed to ischemia or chronic infarction, and therefore identifies patients who have had an acute MI. It is most useful in patients whose ECGs are indeterminate for the diagnosis of acute myocardial infarction (eg, left bundle branch block or permanent pacemaker) or those with inconclusive CK or CK-MB. Diagnostic accuracy and safety of antimyosin imaging has been established. This new cardiac imaging agent holds great potential for future clinical use in the diagnosis and management of patients with known or suspected acute myocardial infarction. Presuming FDA approval, the critical care nurse will see antimyosin used as an innovative and viable alternative in the diagnosis of acute myocardial infarction. Critical care nurses need to continually increase their knowledge of technologic advances and clinical applications for their own professional development, as well as to provide accurate information to patients and their families. In the area of nuclear cardiology, this includes antimyosin imaging and other state-of-the-art imaging techniques such as magnetic resonance imaging, positron emission tomography and computed tomography.