RESUMO
Objective:To observe the effect of high-flow nasal cannula oxygen therapy (HFNC) in patients with chronic obstructive pulmonary disease (COPD) and mild hypercapnia, and to evaluate the early predictive ability of physiological parameters in these patients.Methods:A retrospective cohort study was conducted based on Medical Information Mart for Intensive Care-Ⅳ (MIMIC-Ⅳ) updated in September 2020 and the data of adult patients with COPD and mild hypercapnia [45 mmHg (1 mmHg = 0.133 kPa) < arterial partial pressure of carbon dioxide (PaCO 2)≤ 60 mmHg] from 2008 to 2019 were collected. These patients were assigned to the HFNC group or non-invasive ventilation (NIV) group according to whether they received HFNC or NIV. Baseline data such as gender, age, body mass index (BMI), simplified acute physiology scoreⅡ (SAPSⅡ), Charlson comorbidity index (CCI) and physiological parameters were collected. A propensity score matching was conducted according to the baseline data of the HFNC group patients. The 48-hour and 28-day intubation rates, 28-day mortality, length of intensive care unit (ICU) stay, the length of hospital stay, and the changes in physiological parameters within 48 hours after treatment were compared between the two groups. The receiver operating characteristic curve (ROC curve) was drawn and the ratio of heart rate over pulse oxygen saturation (HR/SpO 2) and ROX index [SpO 2 / (inhaled oxygen concentration, FiO 2×respiratory rate, RR)] were analyzed to predict the 24-hour and 48-hour intubation rates. Results:A total of 524 520 inpatient records were screened and 153 patients were included, while 37 patients in the HFNC group and 116 patients in NIV group. There were 31 patients in the HFNC group and 84 patients in the NIV group remained after propensity score matching according to the baseline data. There were no significant differences in the baseline data of gender, age, BMI, SAPSⅡ, CCI score, physiological parameters and prognosis data except the length of ICU stay. The length of ICU stay in HFNC group was significant longer than that of the NIV group [days: 4.6 (3.1, 10.0) vs. 3.1 (1.6, 5.8), P < 0.05]. HR and RR at 40- 48 hours were significantly lower than those at 0-8 hours after treatment only in the HFNC group [HR (bpm): 84.1±12.2 vs. 91.1±16.4, RR (times/min): 19.8±4.9 vs. 21.6±4.1, both P < 0.05]. Both in the HFNC group and NIV group the pH increased (7.42±0.08 vs. 7.36±0.05 and 7.41±0.06 vs. 7.36±0.05, both P < 0.05) and PaCO 2 decreased significantly [mmHg: 46.3 (39.5, 51.0) vs. 49.8 (45.5, 54.0) and 46.0 (40.5, 51.5) vs. 49.5 (45.5, 55.3), both P < 0.05]. The HR, PaO 2 were higher in the HFNC group than those in the HFNC group at 40-48 hours after treatment [HR (bpm): 91.1±15.4 vs. 84.1±12.2, PaO 2 (mmHg): 99.5 (86.0, 132.3) vs. 85.8 (76.5, 118.0), both P < 0.05], PaO 2/FiO 2 were lower in the HFNC group than that in the HFNC group at 40-48 hours after treatment [mmHg: 223.8 (216.5, 285.0) vs. 278.0 (212.3, 306.0), P < 0.05]. Both HR/SpO 2 and ROX index at 4 hours after treatment had predictive value for 24-hour and 48-hour intubation in the HFNC group. The areas under ROC curve (AUC) of HR/SpO 2 at 4 hours after treatment in the HFNC group were larger than those of ROX index for predicting 24-hour and 48-hour intubation (24-hour: 0.649 vs. 0.574, 48-hour: 0.692 vs. 0.581, both P < 0.01); the 95% confidence interval (95% CI) of 4 hours HR/SpO 2 and for ROX index predicting 24 hours and 48 hours intubation were 0.497-0.780, 0.567-0.799, 0.450-0.694 and 0.454-0.716, respectively. The high sensitivity of HR/SpO 2 and ROX index in predicting 24-hour and 48-hour intubation were 84.6%, 92.9%, 88.2% and 94.4%, respectively, and the low specificity were 52.3%, 23.7%, 54.7% and 29.6%, respectively. Conclusions:HFNC can be used in COPD patients with mild hypercapnia, but it cannot replace NIV. The accuracy of ROX index at 4 hours after HFNC treatment in predicting intubation in COPD patients with mild hypercapnia is poor.
RESUMO
Objective:To explore the early predictors of high flow oxygen treatment failure for post-operation patients with hypoxemia.Methods:The post-operation adult patients with hypoxemia (100 mmHg<PaO 2/FiO 2≤300 mmHg) received high flow nasal cannula (HFNC) oxygen were retrospectively screened in the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The patients were assigned to the treatment success or failure group according to whether receiving reintubation with 48 h after extubation. The risk factors of 48-h reintubation were screened and analyzed by extreme gradient boosting (XGBoost) algorithm. And the predictors were formulated according to the risk factors. The changes of predictors were collected from extubation to 48 h later. The predictors were compared at different time points after extubation between patients weaning successfully and failed with t test. The values at different time after extubation were also compared to the baseline data. The areas under the receiver operating characteristic (ROC) curve were calculated for 48-h reintubation prediction according to values at 4 h before and after extubation, which were compared with those of rapid shallow breathing index (RSBI) and ROX index. The RSBI was defined as the ratio of respiratory rate to tidal volume. The ROX index was defined as the ratio of SpO 2/FiO 2 to respiratory rate. Results:A total of 524 520 medical records were screened and 318 patients were included. There were 38 patients (11.95%) received reintubation within 48 h. According to the XGBoost model, the important features of 48-h reintubation were the duration before extubation, body mass index, simplified acute physiology scoring II, heart rate (HR), PaO 2, mean blood pressure, tidal volume, age, SpO 2 and respiratory rate. Thus HR/PaO 2 and HR/SpO 2 were formulated as predictors for 48-h reintubation according to the above features. The areas under the ROC of HR/PaO 2 and HR/SpO 2 were 0.640 and 0.617 for 48-h reintubation prediction according values at 4 h before extubation, which were larger than those of RSBI (0.537) and ROX index (0.539). According values at 4 h after extubation, the area under the ROC of HR/SpO 2 was 0.657, which was larger than that of ROX index (0.587). When the HR/SpO 2 reached 1.2 at 4 h after extubation, the specificity for 48-h reintubation was 92%. There was significant difference of HR/SpO 2 at 4 h after extubation between patients weaning successfully and failed (1.02 vs 0.92, P<0.05), and no significant difference of ROX index at the same time (8.14 vs 9.27, P>0.05). There were significant differences of HR/SpO 2 and ROX index at 8 to 12 h after extubation between the two groups (both P<0.05). Conclusions:HR/SpO 2 is more early and accurate in predicting HFNC failure than ROX index for post-operation patients with hypoxemia. However, both the predictors should be further evaluated.