Abstract Rationale While clinical criteria are used to diagnose pneumonia in critically ill patients, rates of concordance between a clinician’s suspicion for pneumonia and a diagnosis of lower respiratory tract infection using bronchoalveolar lavage (BAL) results are undefined. Objective(s) To assess rates of concordance between clinically suspected pneumonia and pneumonia diagnosed by BAL and clinical adjudication in mechanically ventilated patients undergoing BAL for suspected pneumonia, and to identify clinical factors and outcomes associated with diagnostic discordance. Methods This was a single-center prospective observational study of intubated, mechanically ventilated patients undergoing BAL for suspected pneumonia. From 2018 to 2022, clinicians were asked to quantify their suspicion for pneumonia on the same day they performed a BAL for the patient with one of the following options: 15%, 30%, 50%, 70% or 85%. Responses were categorized as low (15% to 30%), intermediate (50%) or high (70% to 85%) suspicion for pneumonia and compared to diagnoses of pneumonia based on independent adjudication of clinical data plus BAL results. Results Among 659 patients, 84% (553/659) were adjudicated to have pneumonia based on chart review and BAL results. Clinicians assigned a low suspicion for pneumonia to 20% (109/553) of patients with an adjudicated diagnosis of pneumonia. Clinicians assigned a high suspicion for pneumonia in 28% (30/106) of patients without pneumonia based on adjudication. Amongst patients with an adjudicated diagnosis of pneumonia, there were no significant differences in vital signs or laboratory values between those assigned a low suspicion for pneumonia and those assigned a high suspicion for pneumonia. In patients adjudicated to have culture negative pneumonia (n = 117), those assigned a low suspicion for pneumonia, compared to those assigned a high suspicion for pneumonia, had a longer length of stay in the hospital (36 days vs 18 days, p = 0.02) and ICU (21 days vs 9 days, p = 0.01). Conclusions Over-diagnosis, rather than a missed diagnosis, is the more frequent cause of diagnostic discordance. A low suspicion for pneumonia in patients with an adjudicated diagnosis of culture-negative pneumonia is associated with longer ICU and hospital lengths of stay. There is a need to improve diagnostic accuracy in critically ill patients with suspected pneumonia.
Zhao et al. (Mon,) studied this question.