The main drawbacks of the study were that the 180-day all-cause readmission rates did not achieve statistical significance, and even though the adjusted P values for all-cause 30- and 90-day readmission rates were reported to be significant, their 95% confidence interval for the odds ratio barely meets appropriate analytical criteria (OR 0.59 [0.35-1.00] and 0.64 [0.42-0.99]). Also disappointing was the fact that there was no difference in readmission rates at 30 days for the index diagnosis. Therefore, healthcare systems would likely hesitate to implement these interventions without more definitive data showing reductions in adverse outcomes and mortality rates.
Pleural Empyema in CAP Cases
Ahmed RA, Marrie TJ, Huang JQ. Thoracic empyema in patients with community-acquired pneumonia. Am J Med. 2006 Oct;119(10):877-883.
Pleural effusions complicate up to 44% of cases of community-acquired pneumonia (CAP). Of these cases, 10% develop complicated parapneumonic effusions. In the past, pleural empyema has been associated with poor outcomes and high mortality rate. Unfortunately, most of these studies were performed before the advent of newer antimicrobial agents and more modern diagnostic and therapeutic techniques.
This prospective, population-based study included all patients older than 17 who had been admitted with a diagnosis of CAP. Most of these patients were diagnosed and managed according to a “Pneumonia Critical Pathway.” Adherence to any aspect of the pathway by the admitting physician was completely voluntary.
Of 3,675 patients enrolled in the study, 47 (1.3%) were diagnosed with empyema by the attending physician—a number which correlates with previous studies. Of these, only 24 (0.7%) were ultimately classified as “definite empyema” by one or more of the following criteria:
- Presence of microorganisms on Gram stain or culture of the pleural fluid;
- Pleural fluid with a pH <7.2 plus radiographic evidence suggesting empyema; and
- Frank pus in the pleural space at time of thoracoscopy.
The remaining 23 (0.6%) patients were classified as suspected empyema.
The study then compared the patients without empyema with patients with definite empyema. Patients with definite empyema were younger, more likely to have received antibiotics before admission, and more likely to have been admitted to the ICU. Further, these patients had a higher incidence of illicit drug use and frequently presented with a history of systemic symptoms, including fevers, chills, and pleuritic chest pain. Laboratory studies—aside from elevated WBC—were not useful in distinguishing between the two groups. Also, there were no significant features on chest radiographs to separate the two groups, although in patients with complex fluid collections, 19 of 22 patients (86%) with definite empyema had computed tomography (CT) scans suggesting the diagnosis.
Streptococcus milleri was the most common pathogen, isolated in 50% of patients with definite empyema. Patients with definite empyema were more likely to have invasive diagnostic procedures and had longer hospital stays (23.5 +/- 17 days) compared with their CAP counterparts (12.4 +/- 20.2 days, P=0.007).
Clinical and laboratory features remain nonspecific and should be used with caution when differentiating between empyema and complicated pleural effusions. Diagnostic pleural effusion aspiration is essential if infection is suspected. This study also points out the greater need of ICU support in definite empyema cases that suggest a greater severity of illness.
Interestingly, definite empyema had an in-hospital mortality rate of 4.2%, compared with 10% for CAP (P<0.05). Possible reasons for this result included the fact that 50% of the empyema cases were suspected at admission and thereby received earlier antibiotic treatment and more aggressive management than CAP cases.
Rapid Response Systems: A Call for Research
Devita MA, Bellomo R, Hillman K, et al. Findings of the first consensus conference on medical emergency teams. Crit Care Med. 2006 Sep;34(9):2463-2478.