Repeat bronchoalveolar lavage to guide antibiotic duration for ventilator-associated pneumonia

Duration of Antibiotic Therapy for Early VAP Trial: Study Protocol for a Surgical Infection Society Multicenter, Pragmatic, Randomized Clinical Trial of Four versus Seven Days of Definitive Antibiotic Therapy for Early Ventilator-Associated Pneumonia in Surgical Patients

Background: Current guidelines recommend a seven-day course of antibiotic therapy for patients with ventilator-associated pneumonia (VAP). However, clinical and microbiologic resolution of infection may occur much sooner than seven days, particularly in patients with early VAP. Shortening the course of antibiotic therapy for early VAP likely results in lower antibiotic-associated complications, but it is unclear whether VAP recurrence rates will be higher in patients receiving fewer days of therapy. We propose to compare four days versus seven days of antibiotic therapy for early VAP in surgical patients in a multicenter, pragmatic, randomized clinical trial. Patients and Methods: Eligible patients admitted to a surgical intensive care unit with early VAP, defined as VAP occurring within two to seven days of intubation, will be randomized to receive four or seven days of antibiotic therapy. The two primary outcomes are: VAP recurrence, defined as VAP occurring two to 14 days after completion of initial therapy and antibiotic-free days, defined as the number of days without receiving any antibiotic agents within 30 days from completion of initial therapy. Data will be analyzed using both intention-to-treat and per-protocol strategies. Power analysis was performed assuming non-inferiority of four days vs. seven days for VAP recurrence and superiority of four days versus seven days for antibiotic-free days. The total sample size to detect a 10% difference between groups with 80% power and assuming a 10% dropout rate is 458 patients. Three separate data analyses are planned throughout the trial and sample size will be re-calculated at each interim analysis. Conclusions: The Duration of Antibiotic Therapy for Early VAP (DATE) Trial will enroll surgical patients with early VAP to analyze whether a shorter duration of antibiotic therapy results in similar clinical outcomes while decreasing antibiotic exposure.

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.

Use of Aerosolized Antibiotics in Gram-Negative Ventilator-Associated Pneumonia in Trauma Patients

Ventilator-associated pneumonia (VAP) is associated with significant morbidity (ventilator days, ICU days, and cost) and mortality increase in trauma patients. Multidrug-resistant strains of causative VAP pathogens are becoming increasingly common. Aerosolized antibiotics achieve high alveolar concentrations and provide valuable adjuncts in the treatment of VAP. This study examined the impact of aerosolized antibiotics in the treatment of VAP in trauma patients. Patients with either Acinetobacter baumannii or Pseudomonas aeruginosa VAP over 10 years treated with aerosolized antibiotics (cases) were stratified by age, severity of shock, and injury severity. A frequency-matched (by causative pathogen) control group treated without aerosolized antibiotics was used for comparison. Multivariable logistic regression was used to identify predictors for the use of aerosolized antibiotics. One hundred twenty VAP episodes were identified in 100 patients. Microbiologic resolution was achieved in all patients treated with aerosolized antibiotics. There was no difference in mortality (14.5% vs 15.7%, P = 0.87) and no antibiotic-related complications in either group. Multivariable logistic regression identified VAP persistence and relapse as independent predictors for the use of aerosolized antibiotics. Combined with systemic therapy, aerosolized antibiotics broaden the spectrum of therapy. They are valuable adjuncts with minimal risk of antibiotic resistance and/or systemic complications.

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.

Short-course versus prolonged-course antibiotic therapy for hospital-acquired pneumonia in critically ill adults

BACKGROUND

Pneumonia is the most common hospital-acquired infection affecting patients in the intensive care unit (ICU). However, current national guidelines for the treatment of hospital-acquired pneumonia (HAP) are several years old and the diagnosis of pneumonia in mechanically ventilated patients (VAP) has been subject to considerable recent attention. The optimal duration of antibiotic therapy for HAP in the critically ill is uncertain.

OBJECTIVES

To assess the effectiveness of short versus prolonged-course antibiotics for HAP in critically ill adults, including patients with VAP.

SEARCH METHODS

We searched CENTRAL (2015, Issue 5), MEDLINE (1946 to June 2015), MEDLINE in-process and other non-indexed citations (5 June 2015), EMBASE (2010 to June 2015), LILACS (1982 to June 2015) and Web of Science (1955 to June 2015).

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) comparing a fixed 'short' duration of antibiotic therapy with a 'prolonged' course for HAP (including patients with VAP) in critically ill adults.

DATA COLLECTION AND ANALYSIS

Two review authors conducted data extraction and assessment of risk of bias. We contacted trial authors for additional information.

MAIN RESULTS

We identified six relevant studies involving 1088 participants. This included two new studies published after the date of our previous review (2011). There was substantial variation in participants, in the diagnostic criteria used to define an episode of pneumonia, in the interventions and in the reported outcomes. We found no evidence relating to patients with a high probability of HAP who were not mechanically ventilated. For patients with VAP, overall a short seven- or eight-day course of antibiotics compared with a prolonged 10- to 15-day course increased 28-day antibiotic-free days (two studies; N = 431; mean difference (MD) 4.02 days; 95% confidence interval (CI) 2.26 to 5.78) and reduced recurrence of VAP due to multi-resistant organisms (one study; N = 110; odds ratio (OR) 0.44; 95% CI 0.21 to 0.95), without adversely affecting mortality and other recurrence outcomes. However, for cases of VAP specifically due to non-fermenting Gram-negative bacilli (NF-GNB), recurrence was greater after short-course therapy (two studies, N = 176; OR 2.18; 95% CI 1.14 to 4.16), though mortality outcomes were not significantly different. One study found that a three-day course of antibiotic therapy for patients with suspected HAP but a low Clinical Pulmonary Infection Score (CPIS) was associated with a significantly lower risk of superinfection or emergence of antimicrobial resistance, compared with standard (prolonged) course therapy.

AUTHORS' CONCLUSIONS

On the basis of a small number of studies and appreciating the lack of uniform definition of pneumonia, we conclude that for patients with VAP not due to NF-GNB a short, fixed course (seven or eight days) of antibiotic therapy appears not to increase the risk of adverse clinical outcomes, and may reduce the emergence of resistant organisms, compared with a prolonged course (10 to 15 days). However, for patients with VAP due to NF-GNB, there appears to be a higher risk of recurrence following short-course therapy. These findings do not differ from those of our previous review and are broadly consistent with current guidelines. There are few data from RCTs comparing durations of therapy in non-ventilated patients with HAP, but on the basis of a single study, short-course (three-day) therapy for HAP appears not to be associated with worse clinical outcome, and may reduce the risk of subsequent infection or the emergence of resistant organisms when there is low probability of pneumonia according to the CPIS.

Adherence to an established diagnostic threshold for ventilator-associated pneumonia contributes to low false-negative rates in trauma patients

BACKGROUND

The diagnosis of ventilator-associated pneumonia (VAP) in our institution has followed an established diagnostic threshold (DT) of equal to or greater than 10 colony-forming units (CFU) per milliliter on bronchoalveolar lavage (BAL) based on our previous study (PS). Because mortality from VAP is related to treatment delay, some have advocated a lower DT. The purpose of the current study (CS) was to evaluate the impact of adherence to this DT for VAP on false-negative (FN) rates and mortality in trauma patients.

METHODS

Consecutive patients over 9 years with VAP (defined as ≥10 CFU/mL in the BAL effluent) subsequent to the PS were identified. Data regarding each BAL performed and the colony counts of each organism identified were recorded. An FN BAL result was defined as any patient who had less than 10 CFU/mL and developed VAP with the same organism up to 7 days after the previous culture. The CS was then compared with the PS.

RESULTS

Over 9 years, 1,679 patients underwent 3,202 BALs. Of these, 79% were male, 88% experienced blunt injury, mean age and Injury Severity Score (ISS) were 44 years and 31, respectively. Overall, there were 73 FN BAL results (2.3%) in the CS compared with 3% in the PS (p = 0.092). In those patients with 10 organisms, the FN rate was reduced (7.5% vs. 11%, p = 0.045), and mortality was unchanged (5.4% vs. 8.3%, p = 0.361) in the CS compared with the PS. The use of the threshold equal to or greater than 10 resulted in a cumulative reduction in antibiotic charges of $1.57 million.

CONCLUSION

Continued adherence to the diagnostic threshold of equal to or greater than 10 for quantitative BAL in trauma patients has maintained a low incidence of FN BALs and reduced patient charges without impacting mortality. The purported benefit of a lower threshold is not supported. In addition, the potential sequelae of increased resistant organisms, antibiotic-related complications, and costs associated with prolonged unnecessary antibiotic exposure are minimized.

LEVEL OF EVIDENCE

Prognostic study, level III.

Association of excessive duration of antibiotic therapy for intra-abdominal infection with subsequent extra-abdominal infection and death: a study of 2,552 consecutive infections

BACKGROUND

We hypothesized that a longer duration of antibiotic treatment for intra-abdominal infections (IAI) would be associated with an increased risk of extra-abdominal infections (EAI) and high mortality.

METHODS

We reviewed all IAI occurring in a single institution between 1997 and 2010. The IAI were divided into two groups consisting of those with a subsequent EAI and those without; the data for each group were analyzed. Patients with EAI following IAI were matched in a 1:2 ratio with patients who did not develop EAI on the basis of their Acute Physiology and Chronic Health Evaluation (APACHE II) score±1 point. Statistical analyses were done with the Student t-test, χ(2) analysis, Wilcoxon rank sum test, and multi-variable analysis.

RESULTS

We identified 2,552 IAI, of which 549 (21.5%) were followed by EAI. Those IAI that were followed by EAI were associated with a longer initial duration of antimicrobial therapy than were IAI without subsequent EAI (median 14 d [inter-quartile range (IQR) 10-22 d], vs. 10 d [IQR 6-15 d], respectively, p<0.01), a higher APACHE II score (16.6±0.3 vs. 11.2±0.2 points, p<0.01), and higher in-hospital mortality (17.1% vs. 5.4%, p<0.01). The rate of EAI following IAI in patients treated initially with antibiotics for 0-7 d was 13.3%, vs. 25.1% in patients treated initially for >7 d (p<0.01). A successful match was made of 469 patients with subsequent EAI to 938 patients without subsequent EAI, resulting in a mean APACHE II score of 15.2 for each group. After matching, IAI followed by EAI were associated with a longer duration of initial antimicrobial therapy than were IAI without subsequent EAI (median 14 d [9-22 d], vs. 11 d [7-16 d], respectively, p<0.01), and with a higher in-hospital mortality (14.9% vs. 9.0%, respectively, p<0.01). Logistic regression showed that days of antimicrobial therapy for IAI was an independent predictor of subsequent EAI (p<0.001).

CONCLUSIONS

A longer duration of antibiotic therapy for IAI is associated with an increased risk of subsequent EAI and increased mortality.

A week seems to be weak: tailoring duration of antibiotic treatment in Gram-negative ventilator-associated pneumonia

The optimal length of antimicrobial therapy has not been extensively studied for a great majority of infections and, in critically ill patients affected by ventilator-associated pneumonia, is a persisting and unsolved issue confronting clinicians. The integration of biomarkers, clinical judgment, and microbiologic eradication might help to define a shorter duration for some ventilator-associated pneumonia episodes due to non-fermenting Gram-negative bacilli, but until these strategies are implemented in clinical practice for individualizing antibiotic treatment, a short-course duration does not seem to tailor a long benefit.

Bilateral versus unilateral bronchoalveolar lavage for the diagnosis of ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) complicates the clinical course of critically injured intubated patients. Bronchoscopic bronchoalveolar lavage (BAL) represents an invasive and accurate means of VAP diagnosis. Unilateral and blinded techniques offer less invasive alternatives to bronchoscopic BAL. This study evaluated clinical criteria as well as unilateral directed versus bilateral BAL for VAP diagnosis.

METHODS

A retrospective chart review of 113 consecutive intubated trauma patients with clinically suspected VAP undergoing unilateral versus bilateral BAL was performed with comparison of positive culture results (>10(4) colony-forming units [CFU]/mL). Culture results were compared with chest radiograph (CXR) infiltrates and white blood cell (WBC) count elevation.

RESULTS

Bilateral BAL was more likely to be positive than unilateral BAL (50.4% vs. 25.5%). In 37.1% of bilateral BALs, there was discordance between the sides of positivity or the bacteria isolated. A CXR infiltrate and WBC count elevation did not predict positive BAL.

CONCLUSIONS

Clinical indicators of VAP are inaccurate, and bilateral bronchoscopic BAL is more likely than unilateral BAL to provide a positive sample in intubated trauma patients. Techniques that do not sample both lungs reliably should be avoided for diagnosis in this patient population.

Use of the clinical pulmonary infection score to guide therapy for ventilator-associated pneumonia risks antibiotic overexposure in patients with trauma

BACKGROUND

The clinical pulmonary infection score (CPIS) has been advocated to guide both the diagnosis and duration of therapy in ventilator-associated pneumonia (VAP). However, the clinical, physiologic, and radiologic components of the CPIS may be difficult to differentiate from the systemic effects of injury and inflammation, unnecessarily prolonging VAP therapy. This study evaluates the use of CPIS in determining the appropriate duration of antimicrobial therapy for VAP in patients with critical illness and trauma.

METHODS

Patients with VAP (≥10 CFU/mL in bronchoalveolar lavage [BAL] effluent) over 6 years were evaluated. Duration of antimicrobial therapy was determined by microbiologic resolution (≤10 CFU/mL) on repeated BAL. Recurrence was defined as >10 CFU/mL on BAL performed within 2 weeks of appropriate therapy. A CPIS of less than 6 was used as a threshold for VAP resolution.

RESULTS

Of the patients with VAP, 1,028 were identified: 523 had community-acquired pathogens (mean CPIS, 6.9), and 505 had hospital-acquired (HA) pathogens (mean CPIS, 6.3). Using a CPIS of less than 6 yielded a sensitivity and specificity of 69% and 51% for community-acquired pathogens and 72% and 53% for HA pathogens, respectively. Antimicrobial therapy would have continued inappropriately in 59% of patients. Overall recurrence was 1%, occurring only with HA pathogens (mean CPIS, 5.9).

CONCLUSION

CPIS should not be used to determine VAP resolution in patients with critical injury and trauma. It cannot reliably differentiate VAP from the systemic inflammatory response syndrome in the face of confounding clinical factors. Using CPIS to determine appropriate duration of antimicrobial therapy for patients with trauma is costly and could be harmful by unnecessarily prolonging exposure to antibiotics.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Treatment of methicillin-resistant Staphylococcus aureus ventilator-associated pneumonia with high-dose vancomycin or linezolid

BACKGROUND

The purpose of this study was to determine the clinical cure rate of high-dose vancomycin for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) ventilator-associated pneumonia (VAP) in critically ill trauma patients. Recent trials suggest that a traditional dose of 1 g q12 hours results in unacceptable cure rates for MRSA VAP. Thus, more aggressive vancomycin dosing has the potential to improve efficacy. Based on pharmacokinetic principles, the goal initial dose at the study center has been 20 mg/kg q12 hours or q8 hours since the 1990s.

METHODS

All patients admitted to the trauma intensive care unit from 1997 to 2008 diagnosed with MRSA VAP were retrospectively reviewed. Diagnosis required bacterial growth ≥ 100,000 colony forming units/mL from a bronchoscopic bronchoalveolar lavage, new or changing infiltrate, plus at least two of the following: fever, leukocytosis or leukopenia, or purulent sputum.

RESULTS

Overall, 125 patients with 141 episodes of MRSA VAP were identified. Mean age was 47 years ± 21 years, median Injury Severity Score was 29 (22-43), 70% of patients were male, and the mean length of intensive care unit stay was 38 days ± 35 days. The mean initial vancomycin dose was 18.1 mg/kg/dose with a mean duration of therapy of 11 days. Clinical success was achieved in 88% (125 of 131) of episodes, with microbiological success in 89% (66 of 74) of episodes with a follow-up bronchoscopic bronchoalveolar lavage. Overall mortality was 20% (25 of 125), with death due to VAP in 12 of 25 deaths. Mean initial vancomycin trough concentrations were 10.6 mg/L in the clinical success group and 13.3 mg/L in the clinical failure group (p = not significant).

CONCLUSIONS

High-dose vancomycin provided an acceptable cure rate for MRSA VAP in critically ill trauma patients.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Ventilator-associated pneumonia in burn patients: a cause or consequence of critical illness?

Infectious complications are a constant threat to thermally injured patients during hospitalizations and are a predominant cause of death. Most of the infections that develop in burn patients are nosocomial and of a pulmonary etiology. The bacteria that cause ventilator associated pneumonia (VAP) take advantage of the fact that uniquely among intensive care unit patients endotracheal intubation allows them a 'free' passage to the sterile lower airways; however, the combination of severe thermal injury (systemic immunosuppression) and inhalation injury (local immunosuppression and tissue injury) create an ideal environment for development of VAP. Thus, strategies directed at preventing and treating VAP in burn patients must address not only rapid extubation and VAP prevention bundles known to work in other intensive care unit populations, but therapies directed to more rapid wound healing and restoration of pulmonary patency.

Duration and cessation of antimicrobial treatment

Shortening the duration of antimicrobial therapy is an important strategy for optimizing patient care and reducing the spread of antimicrobial resistance. It is best used in the context of an overall approach to infection management that includes a focus on selecting the right initial drug and dosing regimen for empiric therapy, and de-escalation to a more narrowly focused drug regimen (or termination) based on subsequent culture results and clinical data. In addition to reducing resistance, other potential benefits of shorter antimicrobial courses include lowered antimicrobial costs, reduced risk of superinfections (including Clostridium difficile-associated diarrhea), reduced risk of antimicrobial-related organ toxicity, and improved drug compliance. There have been relatively few randomized clinical trials that study the optimal treatment durations for such serious infections as pneumonia (community- and healthcare/hospital-acquired), complicated intra-abdominal infection, and catheter-related bloodstream infection (CRBSI). Nonetheless, a growing number of studies have explored the possibilities of reducing the duration of antimicrobial therapy for at least certain patients with these infections, under certain circumstances. Professional organizations have compiled these data and used them to develop clinical practice guidelines to aid clinicians in choosing optimal treatment durations for individual patients. Many patients with hospital-acquired pneumonia, ventilator-associated pneumonia, or healthcare-associated pneumonia can be treated for 7-8 days, while 4-7 days and 14-day treatment durations may suffice for many patients with complicated intra-abdominal infections and uncomplicated CRBSI, respectively. This article first provides a general background on the rationale and data supporting shortened courses of antimicrobial therapy, before using 3 case studies to explore the practical implications of current knowledge and treatment guidelines when making decisions about treatment duration for individual patients with healthcare-associated pneumonia, complicated intra-abdominal infection, and CRBSI.

Short-course versus prolonged-course antibiotic therapy for hospital-acquired pneumonia in critically ill adults

BACKGROUND

Pneumonia is the most common hospital-acquired infection affecting patients in the intensive care unit (ICU). However, the optimal duration of antibiotic therapy for hospital-acquired pneumonia (HAP) is uncertain.

OBJECTIVES

To assess the effectiveness of short versus prolonged-course antibiotic administration for HAP in critically ill adults, including patients with ventilator-associated pneumonia (VAP).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1950 to February week 4, 2011), EMBASE (1974 to March 2011), LILACS (1985 to March 2011) and Web of Science (1985 to March 2011).

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) comparing fixed durations of antibiotic therapy, or comparing a protocol intended to limit duration of therapy with standard care, for HAP (including patients with VAP) in critically ill adults.

DATA COLLECTION AND ANALYSIS

Two review authors conducted data extraction and assessment of risk of bias. We contacted trial authors for additional information.

MAIN RESULTS

Eight studies (1703 patients) were included. Methodology varied considerably and we found little evidence regarding patients with a high probability of HAP who were not mechanically ventilated. For patients with VAP, a short seven to eight-day course of antibiotics compared with a prolonged 10 to 15-day course (three studies, N = 508) increased 28-day antibiotic-free days (odds ratio (OR) 4.02; 95% confidence interval (CI) 2.26 to 5.78) and reduced recurrence of VAP due to multi-resistant organisms (OR 0.44; 95% CI 0.21 to 0.95), without adversely affecting other outcomes. However, for cases of VAP due to non-fermenting Gram-negative bacilli (NF-GNB), recurrence was greater after short-course therapy (OR 2.18; 95% CI 1.14 to 4.16; two studies, N = 176), though other outcome measures did not significantly differ. Discontinuation strategies utilising clinical features (one study; N = 302) or procalcitonin (three studies; N = 323) led to a reduction in duration of therapy and, in the procalcitonin studies, increased 28-day antibiotic-free days (mean difference (MD) 2.80; 95% CI 1.39 to 4.21) without negatively affecting other outcomes.

AUTHORS' CONCLUSIONS

We conclude that for patients with VAP not due to NF-GNB, a short fixed-course (seven or eight days) antibiotic therapy may be more appropriate than a prolonged course (10 to 15 days). Use of an individualised strategy (incorporating clinical features or serum procalcitonin) appears to safely reduce duration of antibiotic therapy for VAP.

Clinical and microbiologic outcomes in trauma patients treated for Stenotrophomonas maltophilia ventilator-associated pneumonia

STUDY OBJECTIVES

To determine clinical and microbiologic plus clinical success rates in critically ill trauma patients who received treatment for Stenotrophomonas maltophilia ventilator-associated pneumonia (VAP).

DESIGN

Retrospective medical record review.

SETTING

Level I trauma intensive care unit of a large academic medical center.

PATIENTS

A total of 101 patients who developed S. maltophilia VAP between January 1997 and December 2007.

MEASUREMENTS AND MAIN RESULTS

Patients' baseline demographic and clinical characteristics, as well as characteristics of their VAP, were documented. The primary study outcome was the rate of clinical success in patients with S. maltophilia VAP; a secondary outcome was microbiologic plus clinical success rate in these patients. Standard definitions were employed to determine these outcomes related to VAP treatment. The study population had higher injury severity scores and a higher rate of traumatic brain injury than is typically observed in the study's intensive care unit. The median time to diagnosis of S. maltophilia VAP was 15 days (interquartile range 11-24 days). Stenotrophomonas maltophilia was the sole organism isolated in 34% of patients; the other patients had polymicrobial VAP. Despite inadequate empiric antibiotic therapy being administered to 97% of the patients, the overall clinical success rate was 87%. The microbiologic plus clinical success rate was 82%. The most common treatments for S. maltophilia VAP were trimethoprim-sulfamethoxazole (77 patients received monotherapy, 9 received combination therapy) and ciprofloxacin (6 patients received monotherapy, 8 received combination therapy); all-cause and VAP-related mortality rates were 13% and 7%, respectively.

CONCLUSION

Critically ill trauma patients with S. maltophilia VAP responded well to therapy despite high rates of inadequate empiric antibiotic administration. Trimethoprim-sulfamethoxazole was the most common therapy, but clinical success rates did not differ significantly based on antibiotic selection. This study adds significantly to the available S. maltophilia VAP outcomes data.

Diagnosis, management and prevention of ventilator-associated pneumonia: an update

Ventilator-associated pneumonia (VAP) affects 10-20% of mechanically ventilated patients and is associated with increased morbidity and mortality and high costs. Early diagnosis is crucial for rapid appropriate antimicrobial therapy to be instituted, but debate remains as to the optimal diagnostic strategy. Noninvasive clinical-based diagnosis is rapid but may not be as accurate as invasive techniques. Increased use of biomarkers and advances in genomics and proteomics may help speed up diagnosis. Management of VAP relies principally on appropriate antimicrobial therapy, which should be selected according to individual patient factors, such as previous antibacterial therapy and length of hospitalization or mechanical ventilation, and local infection and resistance patterns. In addition, once bacterial culture and sensitivity results are available, broad-spectrum therapy should be de-escalated to provide a more specific, narrower-spectrum cover. Optimum duration of antibacterial therapy is difficult to define and should be tailored to clinical response. Biomarker levels may be useful to monitor response to therapy. With the high morbidity and mortality, prevention of VAP is important and several strategies have been shown to reduce the rates of VAP in mechanically ventilated patients, including using noninvasive ventilation where possible, and semi-recumbent positioning. Other potentially beneficial preventive techniques include subglottal suctioning, oral decontamination strategies and antimicrobial-coated endotracheal tubes, although further study is needed to confirm the cost effectiveness of these strategies.

Duration of antibiotic therapy for ventilator-associated pneumonia in burn patients

Shorter compared with longer courses of antibiotic therapy for ventilator-associated pneumonia (VAP) in mixed medical-surgical intensive care units (ICUs) have been reported to produce equivalent outcomes. There have been few studies on the duration of antibiotic therapy for VAP in the burn population. We hypothesized that a shorter duration of antibiotic therapy for VAP would produce similar outcomes in our burn ICU. All burn patients from July 2001 to December 2006 admitted to the burn ICU requiring mechanical ventilation were studied. VAP was diagnosed prospectively by our Infection Control Liaison using bronchoalveolar lavage for cultures. Patients were cohorted into two groups: before July 1, 2004, antibiotic therapy duration was directed by the discretion of the attending physician (preprotocol), and after, the goal was 8 days of appropriate therapy or longer based on physician discretion (postprotocol). There were 98 patients treated for VAP with similar rates of inhalation injury, %TBSA burn size, age, and need for mechanical ventilation between the groups. The incidence of recurrent VAP was the same: 17% for the preprotocol and 15% for the postprotocol periods. The overall duration of antibiotic therapy did not change from 11 +/- 4 to 12 +/- 6 days. For patients treated longer than the target of 8 days, 66% had positive respiratory cultures at 4 days after initiation of antibiotic therapy. For the majority of patients with aspiration-type organisms or nonvirulent strains, there were fewer antibiotic days overall at 10 +/- 5 days (P < .05), with no episodes of recurrent VAP with the same bacteria. Despite a focused effort to decrease antibiotic usage for VAP in burn patients, the overall duration of therapy did not change. The majority of patients with virulent organisms such as methicillin-resistant Staphylococcus aureus or nonfermenting Gram-negative rods still had clinical signs of pneumonia and positive cultures, leading clinicians to continue antibiotics. In patients without virulent pathogens, a shorter antibiotic course was well-tolerated without recurrences.

Adjunctive aerosolized antibiotics for treatment of ventilator-associated pneumonia

STUDY OBJECTIVE

To determine clinical and microbiologic success in patients receiving adjunctive aerosolized antibiotics for the treatment of ventilator-associated pneumonia (VAP).

DESIGN

Retrospective medical record review.

SETTING

Level I trauma intensive care unit of a large academic medical center.

PATIENTS

Forty-nine patients (mean +/- SD age 42 +/- 19 yrs) who received aerosolized antibiotics for the treatment of a total of 60 episodes of VAP caused by Pseudomonas aeruginosa and/or Acinetobacter baumannii between January 2001 and July 2007.

MEASUREMENTS AND MAIN RESULTS

Patients were identified by using an existing database of patients with documented VAP at the study center. To receive a diagnosis of VAP, patients had to have bacterial growth of 10(5) or more colony-forming units/ml from a bronchoscopic bronchoalveolar lavage and new or changing infiltrate on chest radiograph, plus at least two of the following: abnormal body temperature (> 38 degrees C or < 36 degrees C), abnormal white blood cell count (> 10 or < 4 x 10(3)/mm(3), or > 10% immature bands), or macroscopically purulent sputum. By reviewing patient data, we evaluated clinical and microbiologic success using standard definitions. The median (interquartile range) Injury Severity Score and admission Acute Physiology and Chronic Health Evaluation II score were 40 (29-45) and 17 (9-21), respectively. Pseudomonas aeruginosa, A. baumannii, or both were isolated in 45, 14, and 1 episode(s), respectively. Eighteen VAP episodes included additional bacteria. Aerosolized tobramycin, amikacin, and colistimethate were used in 44, 9, and 9 episodes, respectively. Systemic antibiotics were used in 59 (98%) of the 60 episodes. Clinical success was achieved in 36 (73%) of the 49 first episodes of VAP, 8 (73%) of 11 subsequent episodes, 17 (85%) of 20 episodes that were failing intravenous monotherapy, and 30 (79%) of 38 episodes with multidrug-resistant P. aeruginosa or A. baumannii. Microbiologic success was achieved in 29 (71%) of 41 evaluable episodes. Six patients died from VAP.

CONCLUSION

Treatment with adjunctive aerosolized antibiotics was associated with a good response rate in critically ill trauma patients with VAP due to nonfermenting gram-negative bacilli. It is noteworthy that episodes of VAP that followed intravenous therapy failure and/or that were due to multidrug-resistant organisms responded well.

Management of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) management depends on the interaction between the infective agent, the host response, and the antimicrobial drug used. After the pathogen reaches the lungs, two outcomes are possible: either the microorganisms are eliminated by the host immune system, or they overcome the immune system and cause pulmonary infection. When a patient is thought to have VAP, two steps are strongly recommended: etiologic diagnostic testing and the immediate initiation of antibiotics. The daily management of VAP remains a challenge for physicians in the ICU. In recent years, a more dynamic approach has evolved, updating local epidemiology, evaluating VAP and diagnostic tools every day, and assessing host response using clinical and biochemical parameters.

Hospital-acquired pneumonia: pathophysiology, diagnosis, and treatment

Hospital-acquired pneumonia (HAP) is one of the most common causes of nosocomial infection, morbidity, and mortality in hospitalized patients. Many patient- and disease-specific factors contribute to the pathophysiology of HAP, particularly in the surgical population. Risk-factor modification and inpatient prevention strategies can have a significant impact on the incidence of HAP. While the best diagnostic strategy remains a subject of some debate, prompt and appropriate antimicrobial therapy in patients suspected of having HAP has been shown to significantly decrease mortality. Because the pathogens responsible for HAP are frequently more virulent and have greater resistance to commonly used antimicrobials than other pathogens, clinicians must have knowledge of the resistance patterns at their institutions to choose appropriate therapy.

Optimal duration of the antimicrobial treatment of ventilator-acquired pneumonia

The optimal duration of antimicrobial treatment of patients with ventilator-associated pneumonia is a major concern for clinicians. We looked for the evidence that a short course of therapy (< or =10 days) is as effective as a traditional long-course therapy (14-21 days). Unfortunately, only one trial (PneumA trial) has focused directly on this question. To further evaluate this issue, we identified trials in which the duration of anti-infective treatment was used as the outcome. Such trials, by providing data on mortality, length of intensive care unit stay and recurrence, may allow for estimating the association between duration of therapy and the aforementioned outcomes. Nine such trials were identified; all reported a decrease in the total length of antibiotic administration (statistically significant in seven) with the application of the intervention studied. Short, as opposed to long, courses of antibiotics did not adversely affect mortality, length of intensive care unit stay or recurrence rates. In conclusion, the available evidence seems to support the use of short-course antimicrobial treatments (< or =10 days) for patients with ventilator-acquired pneumonia not caused by nonfermenting Gram-negative bacilli.

[Duration of antibiotic therapy for ventilator-associated pneumonia: comparison of 7 and 10 days. A pilot study]

OBJECTIVE

To compare the efficiency of a 7-day antibiotics regimen with a 10-day regimen for ventilator-associated pneumonia (VAP).

STUDY DESIGN

Prospective randomized study.

PATIENTS AND METHODS

Adults patients ventilated for more than 48 hours in the intensive care unit (ICU) with a clinical diagnosis of VAP documented by positive quantitative cultures of tracheal aspiration were included in this study. All included patients were randomized in two groups. Ten-day group: 10 days antibiotic therapy, and 7-day group: 7 days antibiotic therapy. Primary judgment criteria were 14- and 28-day mortality, the number of days without antibiotics. Secondary judgments criteria were rate of recurrent pulmonary infection, the evolution of the clinical pulmonary infection scores (CPIS), the length of ICU stay and the length of mechanical ventilation.

RESULTS

Thirty patients were included in this study (16 in the 10-day group and 14 in the 7-day group). The demographic and clinical characteristics of the groups assigned to receive antibiotic therapy for 7 or 10 days were generally similar. The 14-day and 28-day mortality rate following VAP onset were 31.2 and 37.5% in the 10-day group and 7.1 and 35.7% in the 7-day group. The difference was not significant. The number of day without antibiotics and without mechanical ventilation turned out: 1.75 and 2.06 days versus 4.14 and 3.43 days in the 10-day group and 7-day group respectively, the recurrent rate of pulmonary infection (12.5% versus 14.3%, p=0.6), the length of stay in the ICU (27.7 days versus 26.0 days, p=0.8) and the evolution of the CPIS were no different in the two groups.

CONCLUSION

In patients with microbiologically confirmed VAP who received appropriate empirical antibiotic therapy, a 7-day antibiotic regimen was as efficient clinically and microbiologically as a 10-day antibiotic regimen with a reduction of antibiotic use.

Reduction in Inadequate Empiric Antibiotic Therapy for Ventilator-Associated Pneumonia: Impact of a Unit-Specific Treatment Pathway

Empiric antibiotic therapy is routinely initiated for patients with presumed ventilator-associated pneumonia (VAP). Reported mortality rates for inadequate empiric antibiotic therapy (IEAT) for VAP range from 45 to 91 per cent. The purpose of this study was to determine the effect of a unit-specific pathway for the empiric management of VAP on reducing IEAT episodes and improving outcomes in trauma patients. Patients admitted with VAP over 36-months were identified and stratified by gender, age, severity of shock, and injury severity. Outcomes included number of IEAT episodes, ventilator days, intensive care unit days, hospital days, and mortality. Three hundred and ninety-three patients with 668 VAP episodes were identified. There were 144 (22%) IEAT episodes: significantly reduced compared with our previous study (39%) ( P < 0.001). Patients were classified by number of IEAT episodes: 0 (n = 271), 1 (n = 98) and ≥ 2 (n = 24). Mortality was 12 per cent, 13 per cent, and 38 per cent ( P < 0.001), respectively. Multivariable logistic regression identified multiple IEAT episodes as an independent predictor of mortality (odds ratio = 4.7; 95% confidence interval: 1.684–13.162). Multiple IEAT episodes were also associated with prolonged mechanical ventilation and intensive care unit stay ( P < 0.001). Trauma patients with multiple IEAT episodes for VAP have increased morbidity and mortality. Adherence to a unit-specific pathway for the empiric management of VAP reduces multiple IEAT episodes. By limiting IEAT episodes, resource utilization and hospital mortality are significantly decreased.