P0393 / #834: PULMONARY MECHANICS IN SEVERE VIRAL PNEUMONIA IN MECHANICALLY VENTILATED CHILDREN. OVERDISTENTION DOES NOT ALWAYS IS ASSOCIATED TO A PURE OBSTRUCTIVE PATTERN.

Abstract

Aims & Objectives: Information concerning pulmonary mechanics during viral severe pneumonia is rather scarce, mainly in middle/low income settings. We aim to describe the pattern of pulmonary mechanics in these patients, and to assess its changes over time. Methods: Patients admitted to a single PICU with community acquired pneumonia (CAN) requiring mechanical ventilatory support, were prospectively collected during a six-month period (nov 2018-apr 2019). All the patients with proven viral infection were analyzed regarding age, sex, co-morbidities, blood gases, days of ventilatory support [DVS], respiratory mechanics, risk of mortality, organ-dysfunctions, length of stay (LOS), and survival to discharge. Results: Of 50 patients admitted to PICU with respiratory failure requiring mechanical support due to CAN, exclusive viral agents were showed in 28 (56%). Average LOS was 8 (1-20) days. Average DVS was 12. Average oxygen index and PaO2/FiO2 at admission, were 6.2 and 126. In spite of obvious thorax overdistention and wheezing, most patients (19/28, 69.7%) presented, with a mixed pattern in their pulmonary mechanics: a transpulmonary pressure of 3; average auto-PEEP of 1.5; average static compliance was 0.65 ml/cm H20/kg. The expected obstructive pattern was found in 6 cases (22.5%). The pattern tended to change over time, requiring dynamic ventilator adjustment. Conclusions: A pure obstructive pattern must not be assumed in severe viral pneumonia in spite of the presence of wheezing and pulmonary over-distention in the chest X-ray. Pulmonary mechanics must always be assessed, and the ventilatory strategy should be adjusted accordingly.