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CPIS < 6

               If the CPIS < 6, and the Gram stain of the respiratory tract specimen is difficult to interpret, antibiotic therapy can be limited. Whether the CPIS is a good predictor of pneumonia is controversial and numerous studies have questioned its sensitivity and specificity. However, in our approach, the CPIS is not used as a proven aid to diagnose ICU pneumonia; instead, its use is to select those patients who do not need intensive and prolonged broad spectrum antibiotic therapy. The usage for this purpose has been validated in one study (Singh AJRCCM 2000;162:505-51). So, for these patients, we administer antibiotic monotherapy initially. Since the classical signs of pneumonia are largely absent and since the patient is clinically stable, most clinicians would agree that limited antibiotic therapy (monotherapy) of short duration (3 days) is prudent until results of cultures are known. Studies estimate that for ICU patients with pulmonary infiltrates 70%-80% do not have pneumonia, but currently most will receive combination broad spectrum empiric antibiotic therapy with duration from 5-14 days. Receipt of unnecessary antibiotics in patients without confirmed pneumonia is linked to higher mortality (1,2,3,4) (Singh AJRCCM 2000;162:505-51).

               The major reason contributing to “spiraling empiricism” in antibiotic use in the ICU is that physicians are unwilling to risk missing a treatable infection. Because ICU pneumonia carries substantial mortality, administration of broad-spectrum antibiotics to most patients with pulmonary infiltrates has emerged as the predominant practice in the ICU. The use of the CPIS shown in Figure 2 allows the physician flexibility in initially managing patients with a perceived treatable infection. However, the number of antibiotics to be given is limited (monotherapy) as is the duration (3 days). Such an approach has led to decreased costs for antibiotics and minimized the emergence of antimicrobial resistance. As importantly, outcome was more favorable when compared to a control group of patients with CPIS < 6 who received broad spectrum antibiotic therapy for 5-21 days (Singh AJRCCM 2000;162:505-51).



1 Aarts MA, Brun-Buisson C, Cook DJ, et al.  Antibiotic management of suspected nosocomial ICU-acquired infection: does prolonged empiric therapy improve outcome?  Intensive Care Med (United States), Aug 2007, 33(8) p1369-78. [PubMed]

2. Fagon JY, Chastre J, Wolff M, et al. A Tenaillon. Invasive and noninvasive strategies for management of suspected ventilator-associated pneumonia. Ann Intern Med 2000; 132; 621-630. [PubMed]

3. Singh N, Rogers P, Atwood CHW, et al. Short course empiric therapy for patients with pulmonary infiltrates in the intensive care unit. Am J Respir Crit Care Med 2000; 162:505-11. [PubMed]

4. Sterling TR, Ho EJ, Brehm WT, Kirkpatrick MB.  Diagnosis and treatment of ventilator-associated pneumonia--impact on survival. A decision analysis. Chest. 1996 Oct;110(4):1025-34. [PubMed]