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

Fibrinolysis Resistance After Injury Is a Risk Factor for a Hospital-Acquired Pneumonia-Like Disease Pattern

Background: Pneumonia is associated with increased morbidity and costs in the intensive care unit (ICU). Its early identification is key for optimal outcomes, but early biomarkers are lacking. Studies suggest that fibrinolysis resistance (FR) after major abdominal surgery is linked to an increased risk of infection. Patients and Methods: Patients in a randomized controlled trial for hemorrhagic shock were evaluated for FR. Fibrinolysis resistance was quantified by thrombelastography with exogenous tissue plasminogen activator (tPA-TEG) at 24- and 48-hours post-injury and measuring LY30 (%). A receiver-operating characteristics (ROC) curve analysis was used to identify a cutoff for increased risk of pneumonia, which was then validated in ICU patients at risk for venous thromboembolism (VTE). Multivariable logistic regression was used to control for confounders. Results: Forty-nine patients in the hemorrhagic shock cohort had tPA-TEGs at 24- and 48-hours (median ISS, 27; 7% pneumonia). A composite tPA-TEG LY30 of less than 4% at 24 and 48 hours was found to be the optimal cutoff for increased risk of pneumonia. This cohort had a seven-fold increased rate of pneumonia (4% vs. 28%; p = 0.048). Eighty-eight patients in the VTE cohort had tPA-TEGs at 24 and 48 hours post-ICU admission (median ISS, 28; 6% pneumonia). The tPA-TEG LY30 of less than 4% was associated with a 10-fold increased rate of pneumonia (19% vs. 1.5%; p = 0.002). In patients with traumatic brain injury, the same association was found (33% vs. 3.2%; p = 0.006). Adjusting for confounders, the tPA-TEG persisted as a substantial risk factor for pneumonia (adjusted odds ratio [OR], 35.7; 95% confidence interval [CI], 1.9-682; p = 0.018). Conclusions: Fibrinolysis resistance quantified by tPA-TEG within 48 hours of ICU admission is associated with an increased risk of pneumonia in patients in hemorrhagic shock and those at risk for VTE. Prospective validation of the tPA-TEG LY30 optimal cutoff for pneumonia and further investigation into whether endogenous FR is a cause of an altered immunity is warranted.

Provider Perceptions of Antibiotic Initiation Strategies for Hospital-Acquired Pneumonia

Background: The practice of rapidly initiating antibiotic therapy for patients with suspected infection has recently been criticized yet remains commonplace. Provider comfort level has been an understudied aspect of this practice. Hypothesis: We hypothesized that there would be no significant differences in provider comfort level between the two treatment groups. Methods: We prospectively surveyed critical care intensivists who provided care for patients enrolled in the Trial of Antibiotic Restraint in Presumed Pneumonia (TARPP), which was a multicenter cluster-randomized crossover trial that evaluated an immediate antibiotic initiation protocol compared with a protocol of specimen-initiated antibiotic initiation in ventilated patients with suspected new-onset pneumonia. At the end of each enrollment arm, physicians at each center were surveyed regarding their overall comfort level with the recently completed treatment arm, and perception of adherence. Both a paired and unpaired analysis was performed. Results: We collected 51 survey responses from 31 unique participants. Providers perceived a higher rate of adherence to the immediate initiation arm than the specimen-initiated arm (Always Adherent: 37.5% vs. 11.1%; p = 0.045). Providers were less comfortable waiting for objective evidence of infection in the specimen-initiated arm than with starting antibiotic agents immediately (Very Comfortable: 83.3% vs. 40.7%; p = 0.004). For the smaller paired analysis, there was no longer a difference in comfort level. Conclusions: There may be differences in provider comfort levels and perceptions of adherence when considering two different antibiotic initiation strategies for suspected pneumonia in ventilated patients. These findings should be considered when planning future studies.

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.

Early pneumonia diagnosis decreases ventilator-associated pneumonia rates in trauma population

BACKGROUND

Ventilator-associated pneumonia (VAP) is a source of morbidity and mortality for trauma patients. Aspiration events are also common because of traumatic brain injury, altered mental status, or facial trauma. In patients requiring mechanical ventilation, early pneumonias (EPs) may be erroneously classified as ventilator associated.

METHODS

A prospective early bronchoscopy protocol was implemented from January 2020 to January 2022. Trauma patients intubated before arrival or within 48 hours of admission underwent bronchoalveolar lavage (BAL) within 24 hours of intubation. Patients with more than 100,000 colony-forming units on BAL were considered to have EP.

RESULTS

A total of 117 patients underwent early BAL. Ninety-three (79.5%) had some growth on BAL with 36 (30.8%) meeting criteria for EP. For the total study population, 29 patients (24.8%) were diagnosed with VAP later in their hospital course, 12 of which had previously been diagnosed with EP. Of EP patients (n = 36), 21 (58.3%) were treated with antibiotics based on clinical signs of infection. Of EP patients who had a later pneumonia diagnosed by BAL (n = 12), seven (58.3%) grew the same organism from their initial BAL. When these patients were excluded from VAP calculation, the rate was reduced by 27.6%. Patients with EP had a higher rate of smoking history (41.7% vs. 19.8%, p < 0.001) compared with patients without EP. There was no difference in median hospital length of stay, intensive care unit length of stay, ventilator days, or mortality between the two cohorts.

CONCLUSION

Early pneumonia is common in trauma patients intubated within the first 48 hours of admission and screening with early BAL identifies patients with aspiration or pretraumatic indicators of pneumonia. Accounting for these patients with early BAL significantly reduces reported VAP rates.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level IV.

Accuracy of the clinical pulmonary infection score to differentiate ventilator-associated tracheobronchitis from ventilator-associated pneumonia

BACKGROUND

Differentiating Ventilator-Associated Tracheobronchitis (VAT) from Ventilator-Associated Pneumonia (VAP) may be challenging for clinicians, yet their management currently differs. In this study, we evaluated the accuracy of the Clinical Pulmonary Infection Score (CPIS) to differentiate VAT and VAP.

METHODS

We performed a retrospective analysis based on the data from 2 independent prospective cohorts. Patients of the TAVeM database with a diagnosis of VAT (n = 320) or VAP (n = 369) were included in the derivation cohort. Patients admitted to the Intensive Care Centre of Lille University Hospital between January 1, 2016 and December 31, 2017 who had a diagnosis of VAT (n = 70) or VAP (n = 139) were included in the validation cohort. The accuracy of the CPIS to differentiate VAT from VAP was assessed within the 2 cohorts by calculating sensitivity and specificity values, establishing the ROC curves and choosing the best threshold according to the Youden index.

RESULTS

The areas under ROC curves of CPIS to differentiate VAT from VAP were calculated at 0.76 (95% CI [0.72-0.79]) in the derivation cohort and 0.67 (95% CI [0.6-0.75]) in the validation cohort. A CPIS value ≥ 7 was associated with the highest Youden index in both cohorts. With this cut-off, sensitivity and specificity were respectively found at 0.51 and 0.88 in the derivation cohort, and at 0.45 and 0.89 in the validation cohort.

CONCLUSIONS

A CPIS value ≥ 7 reproducibly allowed to differentiate VAT from VAP with high specificity and PPV and moderate sensitivity and NPV in our derivation and validation cohorts.

Serum and alveolar procalcitonin had a weak diagnostic value for ventilator-associated pneumonia in patients with pulmonary infection score ≥ 6

BACKGROUND

Measuring the serum and alveolar procalcitonin level as inflammatory marker in the diagnosis of ventilator-associated pneumonia (VAP) has been taken into account. In this study, serum and alveolar procalcitonin levels in patients with suspected VAP and patients with confirmed VAP were compared.

METHODS

This cross-sectional study was conducted using 50 intubated intensive care unit (ICU) patients, connected to ventilator, from October 2014 to April 2015. 50 patients with clinical pulmonary infection score ≥6 were divided into two groups. Patients whose bronchoalveolar lavage (BAL) has shown the growth of more than 104 CFU/mL were included in confirmed VAP group and other patients were included in suspected VAP group. Serum and alveolar procalcitonin levels were measured and compared between both groups.

RESULTS

Mean age of patients was 69.10 ± 42.13 with a range of 16-90 years, out of which 23 patients were male (46%) and 27 patients were female (54%). Moreover, patients' mean clinical pulmonary infection score was reported to be 7.02 ± 1.07. There was a significant relationship between serum and alveolar procalcitonin in suspected patients and patients with an approved form of pneumonia (p = 0.001 and 0.027). Area under the curve for alveolar procalcitonin was 0.683 (sensitivity = 57%; specificity = 80%) and for serum procalcitonin 0.751 (sensitivity = 71%; specificity = 73%) for the diagnosis of VAP.

CONCLUSION

According to the results of the present study, we can diagnose ventilator-associated pneumonia earlier and more accurately by measuring procalcitonin level (particularly alveolar type) in intensive care unit patients.

How Can We Distinguish Ventilator-Associated Tracheobronchitis from Pneumonia?

Ventilator-associated tracheobronchitis (VAT) might represent an intermediate process between lower respiratory tract colonization and ventilator-associated pneumonia (VAP), or even a less severe spectrum of VAP. There is an urgent need for new concepts in the arena of ventilator-associated lower respiratory tract infections. Ideally, the gold standard of care is based on prevention rather than treatment of respiratory infection. However, despite numerous and sometimes imaginative efforts to validate the benefit of these measures, most clinicians now accept that currently available measures have failed to eradicate VAP. Stopping the progression from VAT to VAP could improve patient outcomes.