[Effect of transcutaneous oximetry on prognosis of patients with severe acute respiratory failure receiving extracorporeal membrane oxygenation].

Objective: To investigate the prognostic value of transcutaneous oximetry in patients with severe acute respiratory failure receiving extracorporeal membrane oxygenation(ECMO). Methods: Forty-nine patients diagnosed as severe acute respiratory failure receiving Venous-Venous(V-V)ECMO were enrolled from January 2013 to December 2015 in intensive care unit(ICU) of Wuxi People's Hospital Affiliated to Nanjing Medical University.The 10-min oxygen challenge test was performed using transcutaneous oximetry 6 h after the initiation of ECMO, and the 10-min oxygen challenge test value(OCT(10)) and oxygen challenge index(OCI) were calculated.The following data were collected: patients' baseline characteristics, results of arterial blood gas analysis, ventilator settings, APACHEⅡ, SOFA and Murray lung injury score. Patients were stratified into the survival group and the death group based on their mortality status at 60 d after initiation of ECMO.Patients' characteristics and clinical data were analyzed with SPSS 22.0 software. Receiver operating characteristics (ROC) analysis for predicting 60 d mortality was carried out to find area under curve (AUC) and threshold levels of OCT(10) and OCI. Analysis of survival probability was carried out by Kaplan-Meier method and log-rank test. Multivariable logistic regression was used to identify factors associated with outcomes. Results: There were 25 patients in the survival group and 24 patients in the death group. The characteristics(i.e., age, sex, primary disease) and clinical data(i.e., results of arterial blood gas, ventilator settings) of the 2 groups were similar (P>0.05). The survival group had a significant higher OCT(10) and OCI [(77±11) mmHg(1 mmHg=0.133 kPa), 0.77±0.17] than the death group [(57±12) mmHg, 0.55±0.13, all P<0.05]. The AUC value of OCT(10) and OCI for predicting 60 d mortality were 0.87±0.07(95%CI: 0.69-0.96, P<0.05) and 0.83±0.18(95%CI: 0.64-0.94, P<0.05) respectively, and the cutoff points for OCT(10) and OCI were 72.00 mmHg and 0.80. Kaplan-Meier survival analysis showed that a OCT(10)≥72 mmHg (81.3% vs 15.4%, χ(2)=7.04, P<0.01) and a OCI≥0.8(77.8% vs 21.7%, χ(2)=13.15, P<0.01) were related to better outcome. Multivariate logistic regression analysis showed that OCT(10)(OR=0.88, 95%CI: 0.80-0.96, P<0.01) and OCI (OR=0.01, 95%CI: 0.001-0.086, P<0.01) were both risk factors associated with 60 d mortality. Conclusion: The OCT(10) and OCI are predictive of mortality for patients with severe acute respiratory failure receiving ECMO support.