Effects of mild hypothermia on pulmonary vascular permeability in patients with acute respiratory distress syndrome / 中华危重病急救医学

ABSTRACT

Objective To study the influence of mild hypothermia on pulmonary vascular permeability in patients with acute respiratory distress syndrome (ARDS) induced by infection.Methods A prospective randomized controlled trial was conducted.Patients with ARDS induced by infection satisfied criteria including age 18-70 years,endotracheal intubation and mechanical ventilation (MV),and without severe coagulation disorder admitted to intensive care unit (ICU) of the First Affiliated Hospital of Guangxi Medical University from May 2012 to November 2015 were enrolled,excluding tumor,burn,cardiac disease,vascular disease,and endovascular surgery within 3 months.The patients enrolled were randomly divided into non-temperature controlled group and mild hypothermia group.The primary diseases in all patients were treated according to the treating principles,including respiratory support,integrated treatment of organ support and symptomatic treatment.Besides,the patients in the mild hypothermia group were administered with systemic hypothermia,and the patients' core body temperature (nasopharyngeal temperature) was rapidly decreased to 34-35 ℃ within 1 hour.Acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score,oxygenation index (PaO2/FiO2),extravascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI) in two groups at 1,24,48,and 72 hours after treatment or core temperature up to standards were monitored respectively.Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of vascular endothelial growth factor (VEGF) in venous blood as well as tumor necrosis factor-α (TNF-α) and surfactant apoprotein A (SP-A) in bronchoalveolar lavage fluid (BALF),and circulating endothelial cell (CEC) was counted.The duration of mechanical ventilation and 7-day survival rate were recorded.Results Fifty-six patients were enrolled,with 32 in non-temperature controlled group and 24 in mild hypothermia group.There was no difference in baseline variables including gender,age,APACHE Ⅱ score,PaO2/FiO2 between two groups.APACHE Ⅱ score,EVLWI,PVPI,VEGF,CEC,and TNF-α in both groups were gradually increased with treatment time prolongation,and PaO2/FiO2 and SP-A were gradually decreased.Compared with non-temperature controlled group,APACHE Ⅱ score (16.34±4.27 vs.19.24 ± 5.95),EVLWI (mL/kg12.17 ± 2.26 vs.12.39 ± 4.71),PVPI (15.40 ± 10.95 vs.16.08 ± 10.24),VEGF (ng/L127.92 ± 31.49 vs.159.12 ± 40.67),CEC (cells/μL4.15 ± 1.79 vs.5.70 ± 2.38),and TNF-α (ng/L147.18 ± 48.85 vs.257.17 ±40.84) in mild hypothermia group were significantly decreased from 24 hours (all P ＜ 0.05),and PaO2/FiO2 [mmHg (1 mmHg =0.133 kPa)175.03± 12.64 vs.162.53 ± 14.15] and SP-A (μg/L80.85 ± 16.18 vs.62.06 ± 17.28) were significantly increased (both P ＜ 0.05),the duration of mechanical ventilation was significantly shortened (days10.38 ± 1.50 vs.15.74 ± 3.06,P ＜ 0.01),and 7-day survival rate was significantly increased (75.0％ vs.46.9％,P ＜ 0.05).Conclusion Mild hypothermia can reduce the pulmonary vascular permeability,and improve pulmonary function in early phase in patients with ARDS,as well as shorten the duration of mechanical ventilation,and decrease short-term mortality.