Bilateral Bronchoalveolar Lavage in Ventilator-associated Pneumonia

Bilateral Bronchoalveolar Lavage Cultures for Diagnosing Ventilator-associated Pneumonia. Microbiologic Concordance and Impact on the Efficacy of Treatment Decisions.

The purpose of this study is to assess microbiologic concordance rates between right- and left-lung bronchoalveolar lavage cultures from patients with suspected ventilator-associated pneumonia, identify predictors of concordance, and evaluate the impact of discordant microbiology on clinicians' ability to prescribe appropriate antibiotic treatments, the investigators conducted a prospective observational study in the general intensive care unit of a large university hospital.

Bronchoscopic sampling of lower respiratory tract secretions is widely used in intensive care units (ICUs) for the microbiological diagnosis of ventilator-associated pneumonia (VAP). However, the importance of selecting a specific lung segment for sampling is still a matter of debate.

Non-bronchoscopic blind mini-bronchoalveolar lavage (BAL) is currently used for the diagnosis of VAP with satisfactory sensitivity and specificity. In the presence of pneumonia, microbiologic concordance between the left and right lungs becomes crucial. If concordance is low, the reliability of blind sampling becomes questionable.

When the bacterial distribution in the right and left lungs of VAP patients has been investigated using bronchoscopic sampling techniques, rates of microbiological concordance between the two specimens have varied widely (from 53% to 92%). The factors potentially associated with concordant culture yields have never been explored, and it is unclear whether the use of guided, bilateral lung sampling would actually improve the appropriateness of the antibiotic regimens prescribed for patients with suspected VAP.

The primary objective of this study is to assess the frequency of microbiologic concordance between the right- and left-lung samples in ICU patients undergoing bronchoscopic BAL performed with two different fiberoptic bronchoscopes for the suspicion of VAP. Secondary objectives are to identify factors associated with such concordance and to evaluate the suitability of treatments prescribed based on unilateral vs. bilateral BAL cultures.

Inclusion Criteria:

• invasive mechanical ventilation of ≥ 48 hours
• clinically suspected pneumonia (simplified Clinical Pulmonary Infectious Score exceeded 6 or chest radiographs with a new or progressive pulmonary infiltrate in a patient with at least two of the following: purulent respiratory secretions, temperature >38°C or <36°C, white blood cell count >12,000/mm3 or <4,000/mm3)

Exclusion Criteria:

• age <18 years
• pregnancy
• absence of informed consent
• an arterial oxygen partial pressure to inspired oxygen fraction ratio (PaO2:FiO2) of ≤150
• use of positive end-expiratory pressure (PEEP) >10 cmH2O
• active uncontrolled bronchospasm
• unstable angina or recent (<6 weeks) myocardial infarction
• unstable arrhythmia
• intracranial hypertension
• platelet count ≤20,000/mm3
• international normalized ratio (INR) or activated partial thromboplastin time (aPTT) ratio >1.5
• documented treatment-limitation orders in the patient's chart