Study objective: Arterial thermal dilution with an integrated fiberoptic monitoring system (COLD Z-021; Pulsion Medical Systems; Munich, Germany) allows measurement of extravascular lung water (EVLW) and pulmonary permeability index (PPI). The aim of this study was to evaluate the widespread clinical assumption that early respiratory failure following burn and inhalation injury is due to interstitial fluid accumulation in the lung.
Design: Clinical, prospective study.
Setting: ICU of a university referral center of burn care.
Patients: Thirty-five severely burned adults (> 20% of body surface area).
Interventions: Resuscitation therapy was guided by the results of hemodynamic monitoring using the intrathoracic blood volume (ITBV) as a cardiac preload indicator. The resuscitation goals included a normalization of preload (ITBV > 850 mL/m2) and cardiac index (> 3.5 L/min/m2) within 24 h after ICU admission. Fluid loading was implemented to reach these goals.
Measurements and results: One hundred forty lung water measurements were performed at 0 h, 12 h, 24 h, and 48 h after admission to the ICU. Significant elevation of EVLW and PPI was found in three measurements (2%) at 48 h after ICU admission, and was in one patient associated with inhalation injury. EVLW and PPI were not significantly different between patients with and without inhalation injury. No correlation was found between resuscitation volume and EVLW (r2 = 0.02) or between the alveolar-arterial oxygen pressure difference and EVLW (r2 = 0.017). Chest radiograph abnormalities were found in 2 of 22 patients with inhalation injury; these were not associated with increased values of EVLW.
Conclusion: Early fluid accumulation in the lung in burned patients is very uncommon, even in the presence of inhalation injury. There is no evidence that thermal injury causes an increase in pulmonary capillary membrane permeability.