Failure of non-invasive respiratory support after 6 hours from initiation is associated with ICU mortality

Diagnosis and Management of Acute Respiratory Failure

Acute hypoxemic respiratory failure is defined by Pao2 less than 60 mm Hg or SaO2 less than 88% and may result from V/Q mismatch, shunt, hypoventilation, diffusion limitation, or low inspired oxygen tension. Acute hypercapnic respiratory failure is defined by Paco2 ≥ 45 mm Hg and pH less than 7.35 and may result from alveolar hypoventilation, increased fraction of dead space, or increased production of carbon dioxide. Early diagnostic maneuvers, such as measurement of SpO2 and arterial blood gas, can differentiate the type of respiratory failure and guide next steps in evaluation and management.

Optimal timing for intubation in patients on non-invasive ventilation: A retrospective cohort study

Background and Aims

The timing of transition from non-invasive ventilation (NIV) to invasive ventilation in the intensive care unit (ICU) is uncertain due to a lack of clinical evidence. This study aimed to identify the optimal timing of intubation in patients with respiratory failure managed with NIVs.

Methods

A single-center observational study was conducted in Tokyo, Japan. Patients in the ICU managed with NIV between 2013 and 2022 were screened. The primary outcome was 28-day invasive ventilator-free days. Statistical analyses used locally estimated scatter plot smoothing (LOESS) and generalized linear mixed models to estimate the association between the timing of transition and prolonged intubation duration.

Results

During the study period, 139 of 589 adult ICU patients receiving NIV transitioned to invasive ventilation. The LOESS curve indicated the longest 28-day ventilator-free days around 24 h after NIV initiation, after which the primary outcome decreased linearly. Late intubation after 24 h of NIV initiation was associated with fewer 28-day ventilator-free days (adjusted mean difference: -0.22 days [95% confidence interval: -0.31, -0.13]).

Conclusion

We identified a non-linear association between the timing of intubation and 28-day invasive ventilator-free days. The critical 24-h time window for patients on NIV was associated with longer 28-day invasive ventilator-free days.

Predictive Accuracy of the ROX Index for Re-Intubation in Mechanically Ventilated Patients With COVID-19

BACKGROUND

Several studies have suggested that high-flow nasal cannula (HFNC) is useful for respiratory support after extubation in subjects with COVID-19 pneumonia, whereas 18% subsequently needed to undergo re-intubation. This study aimed to evaluate whether the breathing frequency (f)-ratio of oxygen saturation (ROX) index, which has been shown to be useful for predicting future intubation, is also useful for re-intubation in subjects with COVID-19.

METHODS

We retrospectively analyzed mechanically ventilated subjects with COVID-19 who underwent HFNC therapy after extubation at 4 participating hospitals between January 2020-May 2022. We evaluated the predictive accuracy of ROX at 0, 1, and 2 h for re-intubation until ICU discharge and compared the area under the receiver operating characteristic (ROC) curve of the ROX index with those of f and SpO2 /FIO2 .

RESULTS

Among the 248 subjects with COVID-19 pneumonia, 44 who underwent HFNC therapy after extubation were included. A total of 32 subjects without re-intubation were classified into the HFNC success group, and 12 with re-intubation were classified into the failure group. The overall trend that the area under the ROC curve of the ROX index was greater than that of the f and SaO2 /FIO2 was observed, although there was no statistical significance at any time point. The ROX index at 0 h, at the cutoff point of < 7.44, showed a sensitivity and specificity of 0.42 and 0.97, respectively. A trend of positive correlation between the time until re-intubation and ROX index at each time point was observed.

CONCLUSIONS

The ROX index in the early phase of HFNC therapy after extubation was useful for predicting re-intubation with high accuracy in mechanically ventilated subjects with COVID-19. Close observation for patients with < 7.44 ROX index just after extubation may be warranted because of their high risk for re-intubation.

Management of Coronavirus Disease-2019 Infection in Pregnancy

Although the majority of pregnant patients who contract severe acute respiratory syndrome coronavirus 2 will have a mild course of illness, pregnant patients with coronavirus disease-2019 are more likely than their nonpregnant counterparts to develop a severe illness with an increased risk of poor maternal and fetal outcomes. Although the extent of research in this specific patient population remains limited, there are tenets of care with which physicians and other providers must be familiar to increase the chances of better outcomes for the two patients in their care.

Risk Stratification in Noninvasive Respiratory Support Failure: A Narrative Review

TOPIC/CLINICAL RELEVANCE

The use of noninvasive respiratory support, including noninvasive ventilation and high-flow nasal cannula therapy, has increased over the years. Failure of noninvasive respiratory support, defined as the need for invasive mechanical ventilation, increases the mortality rate.

PURPOSE

To familiarize critical care nurses with available risk stratification assessments and identify common concepts and limitations.

CONTENT COVERED

Few risk stratification assessments are available to identify patients at risk of failure of noninvasive respiratory support. Although many studies have analyzed risk, substantial variation in study design, definitions, terminology, and outcomes have led to a wide range of findings, making clinical application difficult. Further study is needed to broaden known assessments to general patient populations, determine diagnostic accuracy during critical periods, and analyze noninvasive ventilation and high-flow nasal cannula therapy. Risk stratification could allow for better implementation of preventive strategies and patient education.

CONCLUSION

Future research opportunities include improving study design for risk stratification and implementing preventive strategies for patients requiring noninvasive respiratory support. Clinically, risk stratification can provide an opportunity to share knowledge and facilitate conversations with patients and families.

The ROX index as a predictor of high-flow nasal cannula outcome in pneumonia patients with acute hypoxemic respiratory failure: a systematic review and meta-analysis

Background

The respiratory rate-oxygenation (ROX) index has been increasingly applied to predict the outcome of high-flow nasal cannula (HFNC) in pneumonia patients with acute hypoxemic respiratory failure (AHRF). However, its diagnostic accuracy for the HFNC outcome has not yet been systematically assessed. This meta-analysis sought to evaluate the predictive performance of the ROC index for the successful weaning from HFNC in pneumonia patients with AHRF.

Methods

A literature search was conducted on electronic databases through February 12, 2022, to retrieve studies that investigated the diagnostic accuracy of the ROC index for the outcome of HFNC application in pneumonia patients with AHRF. The area under the hierarchical summary receiver operating characteristic curve (AUHSROC) was estimated as the primary measure of diagnostic accuracy due to the varied cutoff values of the index. We observed the distribution of the cutoff values and estimated the optimal threshold with corresponding 95% confidential interval (CI).

Results

Thirteen observational studies comprising 1751 patients were included, of whom 1003 (57.3%) successfully weaned from HFNC. The ROC index exhibits good performance for predicting the successful weaning from HFNC in pneumonia patients with AHRF, with an AUHSROC of 0.81 (95% CI 0.77–0.84), a pooled sensitivity of 0.71 (95% CI 0.64–0.78), and a pooled specificity of 0.78 (95% CI 0.70–0.84). The cutoff values of the ROX index were nearly conically symmetrically distributed; most data were centered between 4.5 and 6.0, and the mean and median values were 4.8 (95% CI 4.2–5.4) and 5.3 (95% CI 4.2–5.5), respectively. Moreover, the AUHSROC in the subgroup of measurement within 6 h after commencing HFNC was comparable to that in the subgroup of measurement during 6–12 h. The stratified analyses also suggested that the ROC index was a reliable predictor of HFNC success in pneumonia patients with coronavirus disease 2019.

Conclusions

In pneumonia patients with AHRF, the ROX index measured within 12 h after HFNC initiation is a good predictor of successful weaning from HFNC. The range of 4.2–5.4 may represent the optimal confidence interval for the prediction of HFNC outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01914-2.