Current Pneumonia Surveillance Methodology: Similar Underestimation in Trauma and Surgical Patients in the Intensive Care Unit

Recommendations for change in infection prevention programs and practice

Fifty years of evolution in infection prevention and control programs have involved significant accomplishments related to clinical practices, methodologies, and technology. However, regulatory mandates, and resource and research limitations, coupled with emerging infection threats such as the COVID-19 pandemic, present considerable challenges for infection preventionists. This article provides guidance and recommendations in 14 key areas. These interventions should be considered for implementation by United States health care facilities in the near future.

"Risk factors for ventilator-associated pneumonia following cardiac surgery: case-control study"

BACKGROUND

Ventilator-associated pneumonia (VAP) following cardiac surgery is a preventable complication associated with adverse outcomes.

AIMS

We aimed to assess risk factors and outcomes of VAP following cardiac surgery.

METHODS

A matched 1:3 case:control study, including adult patients undergoing cardiac surgery through sternotomy between Sep-2014 to Mar-2017 was conducted in a tertiary-care hospital in Israel. Cases included all patients developing VAP within 30 days after surgery, defined using consensus criteria. Controls were matched for age, gender and surgery type. Operative data were collected prospectively, other data were collected retrospectively. Cox regression was used for adjusted analysis of matched data.

FINDINGS

Out of 946 operated patients, we identified 57 patients with VAP after cardiac surgery (17.7 episodes per 1000 ventilator-days) matched to 149 controls. Significant independent risk factors for VAP included congestive heart failure (OR 2.357 95%CI 1.052-5.281), Chest re-exploration in ICU (OR 10.213 95%CI: 2.235-46.678), preoperative glucose levels (OR 1.1010 per 1 mg/dl increase 95%CI: 1.004-1.019) intraoperative red blood cell transfusions (OR 1.542 per 1 unit 95%CI: 1.109-2.094) and pulmonary hypertension (OR 2.261 95%CI 1.048-6.554). VAP was most commonly caused by Gram-negative pathogens. VAP was associated with higher mortality, longer length of stay, longer need for ventilator support and longer stay in ICU setting.

CONCLUSIONS

Postoperative VAP in cardiac surgery patients is associated with severe clinical outcomes. We identified risk factors that can aid in preventive measures implementation for high risk patients.

Limiting ventilator-associated complications in ICU intubated subjects: strategies to prevent ventilator-associated events and improve outcomes

Introduction: Intubation is required to maintain the airways in comatose patients and enhance oxygenation in hypoxemic or ventilation in hypercapnic subjects. Recently, the Centers of Disease Control (CDC) created new surveillance definitions designed to identify complications associated with poor outcomes. Areas covered: The new framework proposed by CDC, Ventilator-Associated Events (VAE), has a range of definitions encompassing Ventilator-Associated Conditions (VAC), Infection-related Ventilator-Associated Complications (IVAC), or Possible Ventilator-Associated Pneumonia - suggesting replacing the traditional definitions of Ventilator-Associated Tracheobronchitis (VAT) and Ventilator-Associated Pneumonia (VAP). They focused more on oxygenation variations than on Chest-X rays or inflammatory biomarkers. This article will review the spectrum of infectious (VAP & VAT) complications, as well as the main non-infectious complications, namely pulmonary edema, acute respiratory distress syndrome (ARDS) and atelectasis. Strategies to limit these complications and improve outcomes will be presented. Expert commentary: Improving outcomes should be the objective of implementing bundles of prevention, based on risk factors amenable of intervention. Promotion of measures that reduce the exposition or duration of intubation should be a priority.

Variations of the lung microbiome and immune response in mechanically ventilated surgical patients

Mechanically ventilated surgical patients have a variety of bacterial flora that are often undetectable by traditional culture methods. The source of infection in many of these patients remains unclear. To address this clinical problem, the microbiome profile and host inflammatory response in bronchoalveolar lavage samples from the surgical intensive care unit were examined relative to clinical pathology diagnoses. The hypothesis was tested that clinical diagnosis of respiratory tract flora were similar to culture positive lavage samples in both microbiome and inflammatory profile. Bronchoalveolar lavage samples were collected in the surgical intensive care unit as standard of care for intubated individuals with a clinical pulmonary infection score of >6 or who were expected to be intubated for >48 hours. Cytokine analysis was conducted with the Bioplex Pro Human Th17 cytokine panel. The microbiome of the samples was sequenced for the 16S rRNA region using the Ion Torrent. Microbiome diversity analysis showed the culture-positive samples had the lowest levels of diversity and culture negative with the highest based upon the Shannon-Wiener index (culture positive: 0.77 ± 0.36, respiratory tract flora: 2.06 ± 0.73, culture negative: 3.97 ± 0.65). Culture-negative samples were not dominated by a single bacterial genera. Lavages classified as respiratory tract flora were more similar to the culture-positive in the microbiome profile. A comparison of cytokine expression between groups showed increased levels of cytokines (IFN-g, IL-17F, IL-1B, IL-31, TNF-a) in culture-positive and respiratory tract flora groups. Culture-positive samples exhibited a more robust immune response and reduced diversity of bacterial genera. Lower cytokine levels in culture-negative samples, despite a greater number of bacterial species, suggest a resident nonpathogenic bacterial community may be indicative of a normal pulmonary environment. Respiratory tract flora samples were most similar to the culture-positive samples and may warrant classification as culture-positive when considering clinical treatment.

Results from a Quality Improvement Project to Decrease Infection-Related Ventilator Events in Trauma Patients at a Community Teaching Hospital

Ventilator-associated pneumonia (VAP) is linked to increased morbidity and mortality and clinical protocols (VAP bundles) have evolved to minimize VAP. In 2009, a quality improvement project was implemented at our institution to decrease VAP rates in adult trauma patients. AVAP prevention committee was developed, and formal evidence-based education for the nursing and physician staff was introduced. During the study period (2009–2016), 2380 patients required ICU admission to our Level II trauma center. The mean Injury Severity Score was 33 1 12, and there were 17 per cent penetrating and 83 per cent blunt injuries. The early compliance (2010) with the VAP bundle was 65 per cent. Within one year of the implementation of VAP prevention, the compliance increased to >90 per cent. Compliance has been carefully trended and has remained at 100 per cent. All of the aforementioned interventions have resulted in a sustained dramatic decline in VAP, from 12 per cent in 2009 to 0 per cent in 2016. Ongoing education and ICU policy development has become the mainstay of our trauma ICU program. The introduction of evidence-based care education imparted a culture of excellence resulting in favorable outcomes in high-risk trauma patients related to VAP prevention. Ongoing monitoring and education is required to sustain these promising outcomes.

Resistance Trends and Treatment Options in Gram-Negative Ventilator-Associated Pneumonia

PURPOSE OF REVIEW

Hospital-acquired and ventilator-associated pneumonia (VAP) are frequent causes of infection among critically ill patients. VAP is the most common hospital-acquired bacterial infection among mechanically ventilated patients. Unfortunately, many of the nosocomial Gram-negative bacteria that cause VAP are increasingly difficult to treat. Additionally, the evolution and dissemination of multi- and pan-drug resistant strains leave clinicians with few treatment options. VAP patients represent a dynamic population at risk for antibiotic failure and under-dosing due to altered antibiotic pharmacokinetic parameters. Since few antibiotic agents have been approved within the last 15 years, and no new agents specifically targeting VAP have been approved to date, it is anticipated that this problem will worsen. Given the public health crisis posed by resistant Gram-negative bacteria, it is essential to establish a firm understanding of the current epidemiology of VAP, the changing trends in Gram-negative resistance in VAP, and the current issues in drug development for Gram-negative bacteria that cause VAP.

RECENT FINDINGS

Rapid identification technologies and phenotypic methods, new therapeutic strategies, and novel treatment paradigms have evolved in an attempt to improve treatment outcomes for VAP; however, clinical data supporting alternative treatment strategies and adjunctive therapies remain sparse. Importantly, new classes of antimicrobials, novel virulence factor inhibitors, and beta-lactam/beta-lactamase inhibitor combinations are currently in development. Conscientious stewardship of new and emerging therapeutic agents will be needed to ensure they remain effective well into the future.