Early predictors of success of non-invasive positive pressure ventilation in hypercapnic respiratory failure

Duration of noninvasive ventilation is not a predictor of clinical outcomes in patients with acute exacerbation of COPD and respiratory failure

Purpose

Acute exacerbation of chronic obstructive pulmonary disease (COPD) is a major cause of mortality and morbidity. Noninvasive ventilation (NIV) is proven to be effective in the majority of patients with acute exacerbation COPD (AECOPD) complicated with respiratory failure. NIV could be lifesaving but also can delay mechanical ventilation if its efficacy is not assessed in a timely manner. In this study, we analyzed potential predictors of NIV failure in AECOPD in a tertiary medical intensive care unit (MICU). In particular, we wondered whether duration of NIV among those who eventually failed was associated with poor outcomes.

Methods

A retrospective review of consecutive patients with a primary diagnosis of AECOPD requiring NIV admitted to the MICU was conducted for the period between 2012 and 2017. Baseline data included demographics, APACHE III score, albumin level, blood lactate, and blood gas elements. Additional chart review was performed to collect NIV setting parameters on presentation to the MICU. Clinical outcome variables collected included outcome and duration of NIV, duration of invasive mechanical ventilation, MICU length of stay, hospital length of stay, and in-hospital mortality. Multivariate regression analysis was performed to determine independent variables associated with clinical outcomes.

Results

There were 370 patients who met the inclusion criteria; 53.2% were male. Mean age was 64.7 ± 11.2 years old. Mean baseline FEV₁ was 34 ±17% of predicted. Patients had mean pH of 7.20 ± 0.54 and P_aCO₂ of 70.3 ± 28.7 on presentation; 323 patients (87.3%) were successfully weaned off NIV; 47 patients (12.7%) failed NIV and required invasive mechanical ventilation. APACHE III score was higher among patients who failed NIV (68.3±18.9 versus 48.8± 15.2, P < 0.001). In the subset of 47 patients who failed NIV requiring intubation, duration of NIV was 25.0 ± 58.8 h. Multivariate regression analysis yielded a model consisting of APACHE III score and body mass index as predictive variables for NIV failure (C-statistic = 0.809). Duration of NIV was not associated with worse clinical outcomes among patients who failed NIV.

Conclusions

NIV is successful in preventing invasive mechanical ventilation in majority of patients with acute respiratory failure due to COPD. Patients with worse clinical status at presentation are more likely to fail NIV and require mechanical ventilation. In the subgroup of patients who failed NIV, duration of NIV prior to intubation was not associated with poor clinical outcomes.

Predictors of success and failure of non-invasive ventilation use in type-2 respiratory failure

BACKGROUND

Non-invasive ventilation is widely used now a days in patients with hypercapnic respiratory failure. Non-invasive ventilation can be used in Intensive Care Unit setting and wards provided trained staff is there to monitor.

METHODS

This was a prospective observational study of 100 adult patients who were admitted with hypercapnic respiratory failure. Demographic information such as Age, Sex were recorded. Clinical parameters like Respiratory Rate, Heart Rate, Oxygen saturation and Arterial Blood Gas variables like pH, PaCO₂, HCO₃ were measured at the time of admission and at 1st hour, 4 hours and 24 hours after start of non-invasive ventilation. Outcome was recorded as success and failure with Non invasive ventilation.

RESULTS

Out of 100 patients, 76 (76%) managed successfully with non-invasive ventilation and 24 patients (24%) needed intubation and invasive mechanical ventilation in this study. Majority of patients (76%) were with clinical diagnosis of Chronic Obstructive Pulmonary Disease. Respiratory Rate and Heart Rate were significantly lower and showed significant improvement at 1st hour, 4 hours and 24 hours in patients who successfully improved with Non invasive ventilation. Oxygen saturation was found to be significantly higher among patients successfully managed with Non invasive ventilation (84.35 ± 8.55 vs 76.87 ± 7.33) as compared to patients who required intubation. pH was found to be significantly higher (7.28 ± 0.06 vs 7.23 ± 0.05) in patients showing good response to Non invasive ventilation and improvement in pH at 1st hour, 4 hours and 24 hours was observed in patients successfully managed with Non invasive ventilation. PaCO₂ level was found to be significantly lower and significant improvement in PaCO₂ at 1st hour, 4 hours and 24 hours was seen in patients with Non invasive ventilation success.

CONCLUSION

Improvement in clinical parameters like respiratory rate, heart rate, Oxygen saturation and improvement in ABG variables like pH, PaCO2 after 1st and 4 hours of start of Non invasive ventilation and maintaining the improvement at 24 hours are predictors of success of non-invasive ventilation in hypercapnic patients.

Outcome of Noninvasive Ventilation in Acute Respiratory Failure

Background

Noninvasive ventilation (NIV) represents the delivery of positive pressure to the lungs without inserting an endotracheal tube. Noninvasive ventilation has been successfully used in patients with acute respiratory failure. There is a tremendous increase in usage of NIV in clinical settings aiming to reduce complications due to invasive ventilation and to improve resource utilization. It is imperative to watch for outcome of NIV in patients with acute respiratory failure.

Materials and methods

A total of 50 patients were included in this prospective longitudinal study and divided into two groups: type I and type II respiratory failure. All patients were administered bilevel positive airway pressure (BIPAP) ventilator support system using full-face mask or nasal mask depending on the status of the patient. Dyspnea quantitated by modified Borg dyspnea score, heart rate (HR), respiratory rate (RR), blood pressure, and arterial blood gas analysis were assessed at the end of 4, 12, and 24 hours.

Results

Respiratory rate and HR were significantly improved at the end of 4, 12, and 24 hours with NIPPV compared with baseline (0 hour) in both groups (p < 0.01). Statistically significant improvements in pH and PaO₂ was seen with NIPPV at the end of 12 hours and 24 hours (p < 0.001) compared with the baseline in both type I and type II respiratory failure patients. Dryness of mouth and nose was noted in 3 (6.81%) patients with NIPPV.

Conclusion

Study indicates that a trial of BIPAP is effective in improving gas exchange, reducing intubation, and length of stay in hospital in patients with acute respiratory failure.

How to cite this article

Arsude S, Sontakke A, Jire A. Outcome of Noninvasive Ventilation in Acute Respiratory Failure. Indian J Crit Care Med 2019;23(12):556-561.

Non-invasive ventilation in children and adults in low- and low-middle income countries: A systematic review and meta-analysis

PURPOSE

We systematically reviewed the effects of NIV for acute respiratory failure (ARF) in low- and low-middle income countries.

MATERIALS AND METHODS

We searched MEDLINE, CENTRAL, and EMBASE (to January 2016) for observational studies and trials of NIV for ARF or in the peri-extubation period in adults and post-neonatal children. We abstracted outcomes data and assessed quality. Meta-analyses used random-effect models.

RESULTS

Fifty-four studies (ten pediatric/n=1099; 44 adult/n=2904), mostly South Asian, were included. Common diagnoses were pneumonia and chronic obstructive pulmonary disease (COPD). Considering observational studies and the NIV arm of trials, NIV was associated with moderate risks of mortality (pooled risk 9.5%, 95% confidence interval (CI) 4.6-14.5% in children; 16.2% [11.2-21.2%] in adults); NIV failure (10.5% [4.6-16.5%] in children; 28.5% [22.4-34.6%] in adults); and intubation (5.3% [0.8-9.7%] in children; 28.8% [21.9-35.8%] in adults). The risk of mortality was greater (p=0.035) in adults with hypoxemic (25.7% [15.2-36.1%]) vs. hypercapneic (12.8% [7.0-18.6%]) ARF. NIV reduced mortality in COPD (relative risk [RR] 0.47 [0.27-0.79]) and in patients weaning from ventilation (RR 0.48 [0.28-0.80]). The pooled pneumothorax risk was 2.4% (0.8-3.9%) in children and 5.2% (1.0-9.4%) in adults. Meta-analyses had high heterogeneity.

CONCLUSIONS

NIV for ARF in these settings appears to be effective.