[Comparison of extracorporeal membrane oxygenation and mechanical ventilation for inter-hospital transport of severe acute respiratory distress syndrome patients].

OBJECTIVE: To compare inter-hospital transport and clinical outcome in severe acute respiratory distress syndrome (ARDS)patients whom were transported either on extracorporeal membrane oxygenation (ECMO) or on conventional ventilation, and to investigate the optimal means of inter-hospital transport.

METHODS: Eleven patients with severe ARDS who were invalid under conventional ventilation and were transported from other hospitals to Tianjin Third Central Hospital from November 2009 to January 2014 were analyzed. Five patients were transported on ECMO (observation group) and 6 on conventional ventilation (control group). The clinical characteristics, outcomes, transportation, vital signs before and after transportation, respiratory parameters, and Murray score between two groups were compared.

RESULTS: Patients in observation group were significantly older than those in control group [years: 73 (46,77) vs. 34 (23,46), Z=-2.293, P=0.022]. There was no significant difference between observation group and control group in acute pathologic and chronic health evaluation II (APACHEII) score, Murray score, oxygenation index (PaO2/FiO2) before transportation, transit time, and transit distance [APACHEII score: 36 (33,39) vs. 27(23,35), Z=-1.830, P=0.067; Murray score: 3.5 ± 0.3 vs. 3.4 ± 0.2, t = 0.667, P = 0.524; PaO₂/FiO₂(mmHg,1 mmHg=0.133 kPa): 61 ± 14 vs. 63 ± 14, t = -0.249, P=0.809;transit time(minutes): 24 (18, 74) vs. 79 (41, 86), Z=-1.654, P = 0.098; transit distance(km): 12.9 (8.3, 71.8) vs. 72.4 (39.5, 86.8), Z = -1.651, P = 0.099]. There was no significant difference between two groups in vital signs and respiratory parameters before transportation. When arrived in ECMO centre, heart rate, respiratory rate, fractional inspired oxygen, inspiratory pressure and Murray score in observation group were significantly lower than those in control group [heart rate(beat/min):102 ± 16 vs. 136 ± 8, t = -4.374, P = 0.002; respiratory rate(beat/min): 23 ± 3 vs. 37 ± 2, t = -7.967, P = 0.000;fractional inspired oxygen: 0.40 ± 0.05 vs. 0.96 ± 0.09, t=-12.152, P=0.000;inspiratory pressure (cmH₂O, 1 cmH₂O = 0.098 kPa): 21 ± 1 vs. 34 ± 4, t=-6.887, P = 0.000; Murray score: 2.7 ± 0.2 vs. 3.8 ± 0.2, t = -8.573, P = 0.000], but PaO₂/FiO₂was higher than that of control group(mmHg: 278 ± 65 vs. 41 ± 5 , t = 8.075, P = 0.001). Four patients were survived in observation group, and one died from the shortage of oxygen induced lung injury deterioration during transportation. Three patients died in control group, which was directly associated with lung injury deterioration.

CONCLUSIONS: For patients with severe ARDS who need the support of ECMO, ECMO-assisted transfer is safer than conventional ventilation, but transfer should be implemented by experienced team.