Resolution of Clinical and Laboratory Abnormalities after Diagnosis of Ventilator-Associated Pneumonia in Trauma Patients

From bedside to bedside: how iterative clinical research influenced the diagnosis and management of pneumonia at the Elvis Presley Trauma Center

Ventilator-associated pneumonia is a well-acknowledged complication after hospitalization for injury or surgical emergency. The contribution to the literature on this topic by Dr Timothy Fabian and the Memphis group at the Elvis Presley Trauma Center resulted in the contemporary recognition that the diagnosis and management of pneumonia is an essential component of surgical critical care. During three decades, the Memphis group, under Dr Fabian's leadership, performed numerous clinical studies that led to the publication of over 40 articles concerning the epidemiology, diagnosis, and treatment of pneumonia after injury. The purpose of this review is to survey the consecutive studies from Memphis specifically that led to the development of a clinical pathway that has stood the test of time. Examination of the research output during this period provides a case study in how bedside clinical research can inform clinical practice and is a model for applied science in the intensive care unit.

Tigecycline to treat Stenotrophomonas maltophilia ventilator-associated pneumonia in a trauma intensive care unit as a result of a drug shortage: A case series

WHAT IS KNOWN AND OBJECTIVE

Stenotrophomonas maltophilia is an intrinsically multidrug-resistant (MDR) organism which commonly presents as a respiratory tract infection. S. maltophilia is typically treated with high-dose sulfamethoxazole/trimethoprim (SMX/TMP). However, SMX/TMP and other treatment options for S. maltophilia can be limited because of resistance, allergy, adverse events or unavailability of the drug; use of novel agents may be necessary to adequately treat this MDR infection and overcome these limitations.

CASE DESCRIPTION

This small case series describes two patients who underwent treatment with tigecycline for ventilator-associated pneumonia (VAP) caused by S. maltophilia after admission to a trauma intensive care unit. At the time of admission for the two reported patients, a national drug shortage of intravenous (IV) SMX/TMP prevented its use. Tigecycline was chosen as a novel agent to treat S. maltophilia VAP based on culture and susceptibility data, and it was used successfully. Both patients showed clinical signs of improvement with eventual cure and discharge from the hospital after treatment with tigecycline, and one patient demonstrated confirmed microbiological cure with a negative repeat bronchoscopic bronchoalveolar lavage (BAL).

WHAT IS NEW AND CONCLUSION

To our knowledge, this small case series is the first documentation of utilizing tigecycline to treat S. maltophilia VAP in the United States. Although it likely should not be considered as a first-line agent, tigecycline proved to be an effective treatment option in the two cases described in the setting of a national drug shortage of the drug of choice.

Treatment of Achromobacter Ventilator-Associated Pneumonia in Critically Ill Trauma Patients

BACKGROUND

Achromobacter sp are nonfermenting Gram-negative bacilli (NFGNB) that rarely cause severe infections, including ventilator-associated pneumonia (VAP). Data on the treatment of Achromobacter pneumonia are very limited, and the organism has been associated with a high mortality rate. Thus, more data are needed on treating this organism.

OBJECTIVE

To evaluate the treatment of Achromobacter VAP in critically ill trauma patients.

METHODS

This retrospective, observational study evaluated critically ill trauma patients who developed Achromobacter VAP. A previously published pathway for the diagnosis and management of VAP was used according to routine patient care. This included the use of quantitative bronchoscopic bronchoalveolar lavage cultures to definitively diagnose VAP.

RESULTS

A total of 37 episodes of Achromobacter VAP occurred in 34 trauma intensive care unit patients over a 15-year period. The most commonly used definitive antibiotics were imipenem/cilastatin, cefepime, or trimethoprim/sulfamethoxazole. The primary outcome of clinical success was achieved in 32 of 37 episodes (87%). This is similar to previous studies of other NFGNB VAP (eg, Pseudomonas, Acinetobacter) from the study center. Microbiological success was seen in 21 of 28 episodes (75%), and VAP-related mortality was 9% (3 of 34 patients).

CONCLUSIONS

Achromobacter is a rare but potentially serious cause of VAP in critically ill patients. In this study, there was an acceptable success rate compared with other causes of NFGNB VAP in this patient population.

Screening for Ventilator-Associated Pneumonia in the Surgical Intensive Care Unit: A Single-Institution Analysis of 1,013 Lower Respiratory Tract Cultures

BACKGROUND

Refinement of criteria for both screening and initiation of empiric therapy in ventilator-associated pneumonia (VAP) will minimize antibiotic overuse. We hypothesized that variables within the commonly used Clinical Pulmonary Infection Score (CPIS) have unfavorable test performance characteristics.

METHODS

Consecutive bronchoalveolar lavage (BAL) cultures obtained from surgical intensive care unit patients were abstracted (2009-2012). Ventilator-associated pneumonia was defined as ≥10(5) cfu/mL. The CPIS both without (CPISclinical) and with (CPISclinical+GS) the result of gram stain (GS) was calculated. Test performance characteristics for the sample, as well as several subgroups, were compared.

RESULTS

One thousand thirteen lower respiratory tract cultures from 492 patients were analyzed; 438 (43.2%) of cultures were classified as VAP, and 310 of 492 patients (62.4%) had ≥1 episode of VAP. Both CPISclinical and CPISclinical+GS had poor discrimination for VAP (Receiver-operating characteristic area under the curve=0.55 and 0.66, respectively). Sensitivity of CPISclinical using a threshold of >6 was 21%; the lowest threshold for CPISclinical for which the sensitivity was at least 85% was 3. The highest sensitivity among the individual CPIS components was new CXR infiltrate (91.1%). Among the subset of cultures sent during the early VAP window (days intubated 2-5), organisms on GS had a sensitivity of 93.3%. The CPISclinical, CPISclinical+GS, organisms, and neutrophils on GS parameters all became less accurate in both the late VAP window and when screening for recurrent VAP. Every case of VAP had at least one of the following: 1) fever; 2) new CXR infiltrate, or 3) organisms on GS.

CONCLUSION

In this series of BALs, traditional screening tools for VAP missed the majority of microbiological confirmed cases. Screening based on either new CXR infiltrate or fever yielded an acceptably high sensitivity. The only scenario identified in which empiric antibiotics could be withheld safely was the absence of organisms on GS in the early VAP window.