Background: A period of less than our hour from emergency department presentation to first antibiotic dose is a core quality measure for community-acquired pneumonia (CAP). Time pressures might reduce the accuracy of pneumonia diagnosis and lead to unnecessary antibiotic administration.
Study design: Retrospective cohort.
Setting: 365-bed university-affiliated community hospital in Baltimore.
Synopsis: Patients admitted with an initial diagnosis of CAP were studied when the time to first antibiotic dose (TFAD) quality standard was eight hours (n=255) and later when the goal TFAD was four hours (n=293).
At admission, under the eight-hour goal, 45.9% of patients met prespecified diagnostic criteria for CAP, compared with 33.8% of patients under the four-hour goal (odds ratio [OR]=0.61, p=0.004). At discharge, 74.5% of patients had a diagnosis of pneumonia with an eight-hour TFAD standard, vs. 66.9% with a four-hour standard (p=0.05). The most common alternate diagnoses were acute bronchitis, heart failure, and COPD exacerbation.
No significant difference in antibiotic-associated adverse drug events, morbidity, or mortality were detected. Importantly, the goal TFAD reduction did not significantly increase the percentage of patients who received antibiotics within four hours (81.6% when the goal was within eight hours, vs. 85.3% when the goal was within four hours, p=0.21). The study is limited by its retrospective nature and the absence of gold standards for the diagnosis of CAP.
Bottom line: Greater pressure to administer antibiotics early in suspected cases of CAP may decrease diagnostic accuracy, without substantially improving antibiotic administration time.
Citation: Welker JA, Huston M, McCue JD. Antibiotic timing and errors in diagnosing pneumonia. Arch Intern Med. 2008;168(4):351-356.
Do Recruitment Maneuvers and High PEEP Reduce All-cause Hospital Mortality in Acute Lung Injury, ARDS?
Background: Low-tidal-volume ventilation reduces mortality in acute lung injury and acute respiratory distress syndrome (ARDS). Adding methods to open collapsed lung, such as employing recruitment maneuvers or using higher positive end-expiratory pressures (PEEP), may further reduce mortality.
Study design: Randomized controlled trial with blinded analysis. Patients were randomized to ventilation using the ARDS Network protocol (tidal volume of 6 ml/kg predicted body weight, assist control ventilation, low PEEP) vs. a higher PEEP intervention algorithm (using pressure control ventilation but still using 6 ml/kg tidal volume).
Setting: 30 intensive-care units in Canada, Australia, and Saudi Arabia.
Synopsis: Despite higher PEEP in the experimental group (14.6 cm H2O, SD 3.4) vs. the control group (9.8 cm H2O, SD 2.7) during the first 72 hours (p<0.001), there was no difference in all-cause hospital mortality or barotrauma between the two groups. The experimental group did, however, have a lower frequency of refractory hypoxemia (4.6% vs. 10.2%, 95% confidence interval [CI] 0.34-0.86, p=0.01).
At the end of the trial, a difference in the number of patients allocated to each group was noted. Investigation uncovered a programming error that disrupted the specified randomization blocks. Sensitivity analyses, which were not described, indicated that this error did not undermine randomization.
Bottom line: The addition of recruitment maneuvers and high PEEP to low-tidal-volume ventilation in acute lung injury and acute respiratory distress syndrome improved oxygenation but did not lower mortality.
Citation: Meade MO, Cook DJ, Guyatt GH, et al. Ventilation strategy using low tidal volumes, recruitment maneuvers, and high positive end-expiratory pressure for acute lung injury and acute respiratory distress syndrome. A randomized controlled trial. JAMA 2008;299(6):637-645.
Does a Ventilation Strategy Setting PEEP to Increase Alveolar Recruitment, Limit Hyperinflation Improve 28-day Mortality in Acute Lung Injury, ARDS?
Background: The need for lung protection in patients with acute lung injury or acute respiratory distress syndrome (ARDS) is accepted. The optimal level of positive end-expiratory pressure (PEEP) to provide protection yet allow alveolar expansion is debated