Indications and Outcomes of Non-Invasive Ventilation in Patients Presenting with Acute Respiratory Distress to The Emergency Department of A Tertiary Care Hospital: A Prospective Observational Study

Background: Non-invasive ventilation (NIV) provides an effective bridge between supplemental oxygen and invasive ventilation in selected patients with acute respiratory failure, but its early use in the Emergency Department (ED) – particularly outside critical care settings in India – remains underutilised and understudied. The objective is to study the use of NIV in the ED of a tertiary care hospital, identify the conditions in which it is effective, determine causes of NIV failure leading to intubation, assess effectiveness by clinical and arterial blood gas (ABG) parameters, and describe patient disposition. Material and Methods: This prospective observational study enrolled 111 consenting adults presenting to the ED with acute respiratory distress and initiated on NIV between December 2017 and June 2019. Demographic data, comorbidities, provisional diagnosis, and clinical/ABG parameters at hour 0 and hour 1 of NIV were recorded on a structured proforma. Statistical analysis was performed using Stata version 14.2; chi-square or Fisher’s exact tests were used for categorical comparisons, with significance set at p<0.05. Results: Of 111 patients, 63 (56.8%) were male and the majority (54.0%) were aged 51–70 years. A pre-existing comorbidity was present in 72 (64.9%), most commonly COPD (32.4%). The leading ED diagnoses were acute exacerbation of COPD (27.0%), community-acquired pneumonia (CAP, 26.1%), and pulmonary edema due to congestive cardiac failure (CCF, 20.7%). Pulmonary edema (cardiogenic and renal) was the most common diagnosis leading to NIV initiation. Clinical improvement at 1 hour was observed in 89 patients (80.2%), while ABG improvement was seen in 63 (56.8%); this difference was statistically significant (χ²=20.79, p<0.001). Eighteen patients (16.2%) failed NIV and required intubation, most commonly due to worsening respiratory failure. Of the 93 patients successfully managed without intubation, 71 (76.3%) were nonetheless transferred to the High Dependency Unit (HDU) or Intensive Care Unit (ICU) for continued monitoring. Conclusion: NIV was effective in the majority of ED patients with acute respiratory failure, particularly those with COPD exacerbation, cardiogenic pulmonary edema, pulmonary edema due to CKD, and CAP. Clinical assessment, rather than ABG values alone, was the more sensitive early indicator of response. Even successfully managed patients frequently required intensive-care-level monitoring, underscoring that NIV success in the ED does not eliminate the need for vigilant downstream care.

Keywords: Non-invasive ventilation; Emergency department; Acute respiratory failure; COPD; Pulmonary edema; Intubation.