[Characteristics and failure risk factors of sequential high-flow nasal cannula oxygen therapy after weaning from invasive ventilation in patients of surgical intensive care unit].

OBJECTIVE: To investigate the characteristics and failure risk factors of sequential high-flow nasal cannula oxygen therapy (HFNC) after weaning from invasive ventilation.

METHODS: The patients who received sequential HFNC after weaning from invasive ventilation admitted to surgical intensive care unit (ICU) of Peking University People's Hospital from June 1st 2016 to May 31st 2018 were retrospectively analyzed. Clinical variables, respiratory therapy parameters, respiratory variables, cardiac variables and outcomes were reviewed and analyzed. Treatment characteristics of HFNC after weaning was analyzed. Patients were divided into HFNC success group and HFNC failure group according to the failure of HFNC, and the differences between the two groups were compared. The independent risk factors of HFNC treatment failure were analyzed by Logistic regression analysis. The value of predictive treatment failure of risk factors and regression models were analyzed by receiver operating characteristic (ROC) curve.

RESULTS: A total of 99 patients were included, 61 men, and the median age was 67.0 (57.0, 76.0) years old. The medianinitial HFNC flow was 50 (50, 60) L/min, and inspired oxygen concentration (FiO2 ) was 0.50 (0.40, 0.60). Eighteen patients experienced HFNC failure (18.2%). Compared with the HFNC success group, the sequential organ failure assessment (SOFA) score in the HFNC failure group was higher [4 (3, 5) vs. 2 (1, 3), P < 0.01], B type natriuretic peptide (BNP) before HFNC therapy were significant higher [ng/L: 647.2 (399.2, 1 331.3) vs. 127.2 (55.2, 369.5), P < 0.01], and respiratory frequency (RR) and heart rate (HR) were significant faster, mean arterial pressure (MAP) was significant higher, oxygen index (PaO2 /FiO2 ) was significant lower after 30 minutes HFNC treatment [RR (times/min): 26 (22, 28) vs. 19 (17, 21), HR (bpm): 105 (97, 107) vs. 85 (77, 90), MAP (mmHg, 1 mmHg = 0.133 kPa): 104.3 (101.7, 110.7) vs. 92.3 (88.3, 97.7), PaO2 /FiO2 (mmHg): 207.3 (185.8, 402.8) vs. 320.2 (226.2, 361.5), all P < 0.05]. It was shown by multiple Logistic regression analysis that the SOFA score [odds ratio (OR) = 2.818, P = 0.022, β = 1.036], BNP before HFNC treatment (OR = 1.002, P = 0.033, β = 0.002) and HR after HFNC treatment 30 minutes (OR = 1.140, P = 0.032, β = 0.131) were independent risk factors for HFNC treatment failure. It was shown by ROC curve that the area under the ROC curve (AUC) for the prediction of HFNC failure was 0.840, 0.859, 0.860 and 0.962 for SOFA, BNP before HFNC treatment, HR after HFNC treatment 30 minutes, and regression model, all had good forecast values (all P < 0.01).

CONCLUSIONS: HFNC is one of the commonly used oxygen therapy methods in the ICU, but not all patients who are treated as a sequential therapy after invasive mechanical ventilation weaning can benefit from it. SOFA score, BNP before HFNC treatment and HR after 30 minutes HFNC treatment were independent risk factors of HFNC failure. Each independent risk factor and regression model can predict the success of HFNC treatment.