Early prediction of excessive move nasal cannula remedy outcomes utilizing a modified ROX index incorporating coronary heart price | Journal of Intensive Care
Affected person inhabitants and HFNC outcomes
100 and forty-five sufferers have been included within the examine evaluation. Nineteen sufferers have been excluded: six sufferers had HFNC help initiated for bronchoscopy, 5 sufferers have been switched from HFNC to NIV remedy, one affected person had HFNC terminated because of epistaxis, one affected person had HFNC terminated for switch to the working theatre for surgical procedure, and 6 sufferers had a ‘don’t resuscitate or intubate’ order. Immunocompromised sufferers made up 56.6% (n = 82) of the examine inhabitants. Twenty sufferers had just lately obtained chemotherapy for strong organ malignancies, 28 sufferers had an underlying haematological malignancy or a bone marrow transplant, and 29 sufferers have been receiving power immunosuppressive remedy.
Ninety-nine sufferers (68.3%) have been initiated on HFNC for acute hypoxemic respiratory failure (Desk 1). Pneumonia was the most typical main prognosis (87/99, 87.9%). The median P/F ratio was 94 (IQR 74–138), and SOFA rating was 4 (IQR 3–6) on the time of HFNC initiation. Forty-five (45.5%) sufferers required intubation (HFNC failure) at a median of 16 (IQR 7–36) h after HFNC initiation. HFNC failure was related to a better SOFA and APACHE II rating (recorded as the very best rating within the previous 24 h earlier than initiation of HFNC) and an elevated proportion of CXR quadrants affected on the time of HFNC initiation (Desk 1). There have been no important variations discovered within the proportion of immunocompromised sufferers or pre-HFNC arterial blood fuel evaluation (pH, P/F ratio, PaCO2 and serum bicarbonate).
Forty-six sufferers (31.7%) have been initiated on HFNC post-extubation (Desk 2). The median length of mechanical air flow previous to extubation was 114 (IQR 61–194) h. Previous to extubation, the median pH was 7.45 (IQR 7.42–7.48), with a PaCO2 of 41 (IQR 36–44) mmHg and P/F ratio of 164 (IQR 137–184). Sixteen (16/46, 34.8%) sufferers required re-intubation, at a median length of 46 (10–87) h after HFNC initiation. Sufferers with HFNC failure have been extra more likely to be immunocompromised (75% vs 37%, p = 0.029).
In each teams of sufferers (acute respiratory failure and post-extubation), HFNC failure was related to a better hospital and ICU mortality price (Tables 1 and a couple of). Amongst all sufferers with HFNC failure, 22 (22/61, 36.1%) and 38 (38/61, 62.3%) sufferers have been initiated on mechanical air flow inside 12 and 24 h, respectively. Initiation of mechanical air flow after 24 h of HFNC was related to a better in-hospital (78.3% vs 50.0%, p = 0.029) and ICU mortality price (69.6% vs 35.1%, p = 0.009). For the 61 sufferers with HFNC failure, the Kaplan-Meier plot for the chance of being freed from mechanical air flow is proven in Fig. 1a and b, which illustrates that sufferers who didn’t survive hospital admission had an extended length of HFNC earlier than intubation.
Efficiency of the ROX and ROX-HR index
In sufferers initiated on HFNC for acute respiratory failure, after 2, 6, 10 and 24 h, 98 (99.0%), 90 (90.9%), 83 (83.9%) and 67 (67.7%) sufferers remained freed from mechanical air flow, respectively (Desk 3). Sufferers with HFNC failure had a considerably decrease ROX and ROX-HR index recorded in any respect time factors, and a considerably greater coronary heart price was noticed at 1, 2, 4, 10 and 12 h of HFNC (Desk 3). Throughout the first 12 h, each indices appeared to have the very best diagnostic accuracy at 10 h with an AUROC of 0.723 (95% confidence interval (CI) 0.605–0.862) and 0.739 (95% CI 0.626–0.853) for the ROX index and ROX-HR index, respectively. Determine 2 illustrates the proportion of affected person with profitable HFNC for acute respiratory failure, primarily based on ROX-HR index scores at 2 and 10 h.
In sufferers initiated on HFNC post-extubation, 45 (97.8%), 43 (93.5%), 42 (91.3%) and 40 (87.0%) sufferers remained freed from mechanical air flow at 2, 6, 10 and 24 h, respectively (Desk 4). Aside from the 48-h time level, sufferers with HFNC failure had a constantly decrease ROX-HR, whereas no important distinction was seen with the ROX index measured at 2, 4, 8 and 18 h (Desk 4). Coronary heart price alone predicted HFNC outcomes with an AUROC of 0.693 (95% CI 0.529–0.856) and 0.699 (95% CI 0.518–0.881) at 2 and 4 h, respectively. Throughout the first 12 h, the very best AUROC was discovered with the ROX index (0.773, 95% CI 0.617–0.928) and the ROX-HR index (0.804, 95% CI 0.660–0.948) at 10 h of HFNC remedy. Determine S2 illustrates the proportion of affected person with profitable HFNC after a deliberate extubation, primarily based on ROX-HR index scores at 2 and 10 h.
In all sufferers, HFNC success was related to a considerably greater improve in ROX-HR index from the two to 10 h and 6 to 10 h time factors—this was not noticed with the ROX index (Desk S1).
Evaluating cutoffs of the ROX-HR and ROX index for sufferers with acute respiratory failure
Utilizing the ROC curve at 10 h into HFNC remedy, cutoffs for the ROX and ROX-HR have been decided to be 5.80 and 6.80, respectively, for the prediction of HFNC success. The sensitivity, specificity, constructive predictive worth (PPV) and destructive predictive values (NPV) of every index at 2, 6, 10, 18 and 24 h are summarised in Desk 5. With Cox proportional regression evaluation, a ROX-HR index of > 6.80 was related to a decrease danger of HFNC failure in any respect time factors within the first 24 h, even after correcting for doable confounders (Gender, APACHE II rating, CCI and the variety of CXR quadrants concerned) (Desk 6). Kaplan-Meier plots illustrating important variations in chance of HFNC success with a cutoff of 6.80 for the ROX-HR index are illustrated in Fig. 3a–c. A second cutoff of ROX < 5.00 and ROX-HR < 5.00 was decided from the ROC curves at 10 h, and their efficiency for the predictirised in Desk S2. In comparison with ROX < 5.00, a ROX-HR index < 5.00 appeared to carry out with greater constructive and decrease destructive probability ratios at 6, 10, 18 and 24 h.
We evaluated the ROX index primarily based on beforehand established cutoffs of 4.88 (by Roca et al.) at 2, 6 and 12 h (Desk S3 and S4) . Equally, as with a ROX index > 5.80, there was no important affiliation of a decrease danger of HFNC failure with a ROX index ≥ 4.88 at 12 h (Desk S3). Roca et al. additionally reported cutoffs of two.85, 3.47 and three.85 at 2, 6 and 12 h for the ROX index for the prediction of HFNC failure . We evaluated these cutoffs in our examine inhabitants, whereas these cutoffs carried out with good specificity (> 95%), the sensitivity remained poor (< 15%). In distinction, a ROX-HR index of < 4.50 at 2 h and < 5.00 at 6 and 12 h performed with reasonable sensitivity (> 34%) and specificity (> 88%).
Evaluating cutoffs of the ROX-HR and ROX index for sufferers extubated to HFNC
A cutoff of seven.00 and eight.00 was decided for the ROX and ROX-HR index, respectively, primarily based on the ROC curves at 10 h into HFNC remedy. Desk 5 summarises the sensitivity, specificity, PPV and NPV of the cutoffs at numerous time factors inside 24 h of HFNC initiation. The ROX-HR index carried out with equal or greater sensitivity and specificity at 2, 6 and 10 h (Desk 5). On univariate Cox proportional regression evaluation, a ROX-HR index of > 8.00 was considerably related to a decrease danger of HFNC failure at 6 and 10 h, which was not seen with the ROX index >7.00 (Desk 7). Kaplan-Meier plots illustrating the chance of HFNC success with a cutoff of 8.00 for the ROX-HR index at 2, 6 and 10 h are proven in Fig. 3d, e. A second cutoff of 6.00 was decided from ROC curves at 10 h, and the efficiency of a cutoff of ROX < 6.00 and ROX-HR < 6.00 for the prediction of HFNC failure can also be summarised in Desk S2.