[Extracorporeal membrane oxygenation for acute respiratory distress syndrome caused by acute phosgene poisoning: a report of 4 cases]

Abstract

Objective: To evaluate the protective effect and curative effect of early treatment with extracorporeal membrane oxygenation (ECMO) in severe patients with acute respiratory distress syndrome (ARDS) caused by acute phosgene poisoning.

Methods: The course of treatment of 4 cases of ARDS caused by acute phosgene poisoning admitted to intensive care unit (ICU) of Jiangxi Provincial People's Hospital in April 2018 was retrospectively analyzed. The treatment parameters in patients before and after the ECMO treatment at 1, 3, 7 days were collected, including pH of the arterial blood, arterial partial pressure of carbon dioxide (PaCO₂), arterial partial pressure of oxygen (PaO₂), blood lactic acid (Lac) and systemic vascular resistance index (SVRI), cardiac index (CI), extravascular lung water index (ELWI), plateau pressure (Pplat), positive end-expiratory pressure (PEEP), driving pressure (ΔP), and acute physiology and chronic health evaluation II (APACHE II), the length of ICU stay, the treatment duration of ECMO and the duration of mechanical ventilation.

Results: After admitted in hospital, the 4 patients were all put on tracheal intubation and ventilator, but the ventilator support conditions were high, the oxygenation and internal environment were unstable. Therefore, ECMO therapy was performed on the next day after admission. Oxygenation was improved obviously after treatment, ventilator support conditions could be obviously reduced, including 3-6 mL/kg of the small tidal volume, 8-10 cmH₂O (1 cmH₂O = 0.098 kPa) of the PEEP, 0.30 of the inhaled oxygen concentration (FiO₂), and other lung protection rest strategies. The parameters were improved obviously after the ECMO treatment compared with before, from the 1st day after the ECMO treatment, PaO₂, SVRI rose obviously, Lac, ELWI, Pplat, PEEP, ΔP, APACHE II were significantly decreased [PaO₂ (mmHg, 1 mmHg = 0.133 kPa): 85.5±10.7 vs. 54.2±4.5, SVRI (kPa×s×L^-1×m^-2): 153.6±9.4 vs. 118.0±12.6, Lac (mmol/L): 2.15±0.19 vs. 4.93±0.96, ELWI (mL/kg): 17.73±2.99 vs. 20.45±4.13, Pplat (cmH₂O): 19.25±2.21 vs. 35.75±2.22, PEEP (cmH₂O): 9.0±1.2 vs. 13.5±1.7, ΔP (cmH₂O): 10.25±1.26 vs. 22.25±3.86, APACHE II: 17.25±2.22 vs. 26.50±2.08, all P < 0.05]; pH and CI were significantly increased after 3 days treatment, and PaCO₂ was significantly decreased [pH: 7.43±0.05 vs. 7.21±0.13, CI (mL×s^-1×m^-2): 64.35±3.17 vs. 59.51±3.17, PaCO₂ (mmHg): 42.0±2.2 vs. 55.0±8.5, all P < 0.05]. All the 4 patients were treated successfully and discharged after improvement. The length of ICU stay was 8-27 days, with an average (13.5±9.0) days; the treatment duration of ECMO was 6-12 days, with an average (8.0±2.7) days; the duration of mechanical ventilation was 6-20 days, with an average (10.75±6.19) days.

Conclusions: Early treatment with ECMO can significantly improve the oxygenation of severe ARDS caused by acute phosgene poisoning, eliminate excessive CO₂ in the body, reduce ventilator-associated lung injury, and improve the prognosis.