Efficacy of an extravascular lung water-driven negative fluid balance protocol

Objective: To analyze the efficacy of negative fluid balance in hypoxemic patients with an elevated extravascular lung water index (EVLWI). Design: A retrospective observational study was made. Setting: Intensive Care Unit of Virgen de las Nieves Hospital (Spain). Participants: Forty-four patients participated in the study. Interventions: We analyzed our database of hypoxemic patients covering a period of 11 consecutive months. We included all hemodynamically stable and hypoxemic patients with EVLWI. >. 9. ml/kg. The protocol dictates a negative fluid balance between 500 and 1500. ml/day. We analyzed the impact of this negative fluid balance strategy upon pulmonary, hemodynamic, and renal function. Main variables of interest: Demographic data, severity scores, clinical, hemodynamic, pulmonary, metabolic and renal function data. Results: Thirty-three patients achieved negative fluid balance (NFB group) and 11 had a positive fluid balance (PFB group). In the former group, PaO₂/FiO₂ improved from 145 (IQR 106, 200) to 210mmHg (IQR 164, 248) (p<0.001), and EVLWI decreased from 14 (11, 18) to 10ml/kg (8, 14) (p<0.001). In the PFB group, EVLWI also decreased from 11 (10, 14) to 10ml/kg (8, 14) at the end of the protocol (p=0.004).For these patients there were no changes in oxygenation, with a PaO₂/FiO₂ of 216mmHg (IQR 137, 260) at the beginning versus 205mmHg (IQR 99,257) at the end of the study (p=0.08). Conclusion: Three out of four hypoxic patients with elevated EVLWI tolerated the NFB protocol. In these subjects, the improvement of various analyzed physiological parameters was greater and faster than in those unable to complete the protocol.Patients who did not tolerate the protocol were usually in more severe condition, though a larger sample would be needed to detect specific characteristics of this group.