ABSTRACT
Ventilator-associated pneumonia [VAP] is the leading cause of death amongst hospital-acquired infections. Despite this, the diagnosis of VAP remains challenging and there is a lack of diagnostic standardization. In humans, glucose concentrations are normally low in nasal and bronchial fluid, but are elevated by inflammation or hyperglycaemia. Exhaled breath condensate glucose was reported to be a potential marker of both infection and outcome in patients with acute respiratory distress syndrome [ARDS]. To study the signifcance of detecting glucose in bronchial aspirate in mechaniclly ventilated patients under tight glycemic control and using it as a follow up parameter in patients with VAP versus patients with community acquired pneumonia [CAP]. Also the present work aimed to describe the pattern of changes of C - reactive protein [CRP] in patients with VAP versus those with CAP. Forty patients were enrolled into the present study and were divided into 3 groups: Group I: Thirty critically ill patients requiring intubation and mechanical ventilation were followed up from admission and daily till they fulfilled criteria suggesting development of VAP. Group II: Ten patients with community acquired pneumonia [CAP]. Group III: Ten healthy volunteers constituting the control group. Patients were assessed using the following scoring systems: 1] Assessing the disease severity using the Acute Physiological And Chronic Health Evaluation scoring system [APACHE II] on the day of admission, 2] Daily assessment of disease severity using the Sequential Organ Failure Assessment [SOFA] score, and 3] the Clinical pulmonary infection score [CPIS]. All patients with CAP were evaluated by Pneumonia severity index [PSI] on admission. CRP was assessed on admission, on day 2 and on day 7. All patients were under tight glycemic control to abolish the effect of hyperglycemia on the bronchial aspirate glucose levels. Glucose measurements were performed simultaneously in the blood and bronchial aspirates. Bronchial aspirates were analyzed for glucose on the day of admission and daily. The present study demonstrated a correlation between the presence of glucose in the bronchial aspirates from mechanically ventilated patients and development of VAP. Glucose in the bronchial aspirates preceded the development of VAP in the first 48 hours of mechanical ventilation and steadily increased thereafter. This was later associated with infiltrates on the chest radiographs, increased levels of CRP, with significant CPIS score. In contrast the glucose level in the sputum from patients with CAP was high on admission then steadily decreased till discharge. There was no correlation between patient's blood glucose and the glucose level in the bronchial aspirate. In the present study CRP values in patients with CAP steadily decreased from admission till the patients were discharged. The mean CRP value in the mechanically ventilated patients at day one was statistically significant less than that in patients with CAP. While at the 7[th] day, the mean CRP value in patients with VAP was higher than that in patients with CAP. The mean CRP level in patients with VAP was higher in nonsurvivors than survivors. In critically ill patients kept under tight glycemic control, early detection of glucose in bronchial aspirates may improve the ability of clinicians to early recognize the onset of VAP. This technique is simple, rapid, and inexpensive and following it daily may serve as a marker for infection or clinical resolution. CRP levels in patients with CAP steadily decrease from time of admission till discharge, whereas in patients with VAP, CRP steadily increases from time of VAP development thereafter thus suggesting a role in following such patients as a prognostic marker