Neurogenic pulmonary edema and variations of emodynamic volumetric parameters in children following head trauma

Background: Currently there is no clear evidence of how changes in hemodynamic parameters are involved in the onset of neurogenic pulmonary edema. Aim of the study has been to correlate the principal variations of the intracranial pressure and volumetric hemodynamic parameters with the variations of extravascular lung water following severe head trauma in children. Methods: We studied 28 children, 16 males and 12 females, mean ± SD age 71 ± 29 months (range 24 - 130 months), admitted for traumatic head injury with Glasgow Coma scale ≤8. All patients received volumetric hemodynamic, and intracranial pressure monitoring following initial resuscitation and every four hours thereafter or whenever a hemodynamic deterioration was suspected. All readings were divided in 2 groups: with intracranial pressure (ICP) >15 mmHg or ≤15 mmHg. Results: During the cumulative in hospital stay a total 508 sets of measurements were done. In the group with ICP >15 mmHg vs that with ICP ≤15 mmHg we observed increased Extravascular Lung Water Index (EVLWi) (11.05±2.28 vs 6.96±0.87 p< 0.0001) and pulmonary permeability (8.50±1.19 vs 5.08±0.90 p<0.0001), and decreased systemic vascular resistances, (1,451±371 vs 1,602±447 p< 0.0001) cerebral perfusion (48.87±18.67 vs 69.72±11.36 p< 0.0001) and PaO2/FiO2 ratio (349±122 vs 490±96 p< 0.0001). There was a significant correlation between EVLWi and pulmonary permeability (R^2 = 0.83, p< 0.0001). Fluid overload and cardiac functional index did not change significantly. Conclusions: the increased EVLWi observed in children following severe head trauma seems mainly related with pulmonary vascular permeability which is significantly increased when ICP is >15mmHg.