Early predictors of success of non-Invasive ventilation in acute hypercapnic respiratory failure

Abstract

Non-invasive ventilation (NIV) has emerged as a significant advancement in the management of acute hypercapnic respiratory failure. Non-invasive positive pressure ventilation (NIV) using face mask or nasal mask which works by providing pressure support that gives ventilatory assistance during inspiration, allows respiratory muscles to work less, increases the volume inspired per minute and improves arterial blood gas (ABG) levels. Its use has become more common as its benefits are increasingly recognized. However, the frequency of success of NIV in patients with acute respiratory failure varies amongst studies. In some patients, with acute hypercapnic respiratory failure, NIV is inadequate and invasive ventilation is required for management of respiratory failure. Failure of initial trial of NIPPV can lead to a delay in endotracheal intubation thus causing an increase in morbidity and mortality. Thus, determination of early predictors of success of NIPPV is important to identify the patients who are likely to benefit from NIPPV. Aim of The Study: To identify the early predictors of success of non-invasive positive pressure ventilation in patients admitted with acute hypercapnic respiratory failure. Materials and Methods: Patients with acute hypercapnic respiratory failure requiring ventilation therapy with respiratory rate [RR] of > 23 breaths per minutes, PaCO2 > 45 mm Hg and arterial pH < 7.35 (despite maximum medical treatment on controlled oxygen therapy) were included in the study. Baseline parameters such as heart rate (HR), respiratory rate (RR), oxygen saturation (SPO2) and Arterial blood gas [ABG] were collected and the same had been re-evaluated at 2, 24 hours and before discharge after initiation of NIV. Change in these parameters, need for intubation and survival to discharge were analyzed. Results: Total number of patients included was 50; 54% were males and 46% were females. Mean age was 65.2 ± 10.2 yrs. Overall survival to discharge with NIV management was 74%. Intubation rate was 34%. No death occurred during NIV. Average length of stay in NIV success group was 7.32 ± 2.25 days. H Statistical significance observed in variables such as p , PaCO2, SPO2, HR and RR at baseline and H statistical improvement observed in p , HR, RR at 2 hours after initiation of NIV. ROC curve analysis HH showed a value below baseline p of 7.14, SPO2 below 79% and 2 hr p of 7.32, had higher chance of NIV failure. Conclusion: Early predictors such as degree of acidosis, PaO2, PaCO2, HR, RR, SPO2 have significant role in identifying patients who were benefitted by NIV thus preventing the delay in initiation of invasive ventilation.

Keywords

• acute hypercapnic respiratory failure
• niv
• intubation rate
• early predictors of success