Ward-Based Noninvasive Ventilation for Acute Hypercapnic Respiratory Failure Unrelated to Chronic Obstructive Pulmonary Disease

Background. The use of ward-based noninvasive ventilation (NIV) for acute hypercapnic respiratory failure (AHRF) unrelated to chronic obstructive pulmonary disease (COPD) remains controversial. This study evaluated the outcomes and failure rates associated with NIV application in the ward-based setting for patients with AHRF unrelated to COPD. Methods. A multicentre, retrospective cohort study of patients with AHRF unrelated to COPD was conducted. COPD was not the main reason for hospital admission, treated with ward-based NIV between February 2004 and December 2018. All AHRF patients were eligible; exclusion criteria comprised COPD patients, age < 18 years, pre-NIV pH < 7.35, or a lack of pre-NIV blood gas. In-hospital mortality was the primary outcome; univariable and multivariable models were constructed. The obesity-related AHRF group included patients with AHRF due to obesity hypoventilation syndrome (OHS), and the non-obesity-related AHRF group included patients with AHRF due to pneumonia, bronchiectasis, neuromuscular disease, or fluid overload. Results. In total, 479 patients were included in the analysis; 80.2% of patients survived to hospital discharge. Obesity-related AHRF was the indication for NIV in 39.2% of all episodes and was the aetiology with the highest rate of survival to hospital discharge (93.1%). In the multivariable analysis, factors associated with a higher risk of in-hospital mortality were increased age (odds ratio, 95% CI: 1.034, 1.017–1.051, P < 0.001 ) and pneumonia on admission (5.313, 2.326–12.131, P < 0.001 ). In the obesity-related AHRF group, pre-NIV pH < 7.15 was associated with significantly increased in-hospital mortality (7.800, 1.843–33.013, P = 0.005 ); however, a pre-NIV pH 7.15–7.25 was not associated with increased in-hospital mortality (2.035, 0.523–7.915, P = 0.305 ). Conclusion. Pre-NIV pH and age have been identified as important predictors of surviving ward-based NIV treatment. Moreover, these data support the use of NIV in ward-based settings for obesity-related AHRF patients with pre-NIV pH thresholds down to 7.15. However, future controlled trials are required to confirm the effectiveness of NIV use outside critical care settings for obesity-related AHRF.

Apnea-Hypopnea Index in Chronic Obstructive Pulmonary Disease Exacerbation Requiring Noninvasive Mechanical Ventilation with Average Volume-Assured Pressure Support

Introduction. This study intends to determine the Apnea-Hypopnea Index in patients hospitalized with acute hypercapnic respiratory failure from chronic obstructive pulmonary disease exacerbation, who require noninvasive ventilation with average volume-assured pressure support (AVAPS), as well as describes the clinical characteristics of these patients. Materials and Methods. We designed a single-center prospective study. The coexistence of Apnea-Hypopnea Index and clinical, gasometric, spirometric, respiratory polygraphy, and ventilatory characteristics were determined. The clinical characteristics found were categorized and compared according to the Apnea-Hypopnea Index (AHI) < 5, AHI 5–15, and AHI >15. A p value <0.05 was considered statistically significant. Results. During the study period, a total of 100 patients were admitted to the ICU with a diagnosis of acute hypercapnic respiratory failure due to COPD exacerbation. 72 patients presented with acute respiratory failure and fulfilled criteria for ventilatory support. Within them, 24 received invasive mechanical ventilation and 48 NIV. After applying the inclusion criteria for this study, 30 patients were eligible. An AHI >5 was present in 24 of the 30 patients recruited (80%). Neck circumference (cm), Epworth scale, and Mallampati score evidenced significant differences when compared to the patient’s AHI <5, AHI 5–15, and AHI >15 ( p < 0.05 ). Furthermore, patients with an AHI >5 had longer hospital admissions, prolonged periods on mechanical ventilation, and a higher percentage of intubation rates. Conclusion. Apnea-Hypopnea Index and chronic obstructive pulmonary disease exacerbation are a frequent association found in patients with acute hypercapnic respiratory failure and COPD exacerbations that require NIV. This association could be a determining factor in the response to NIV, especially when AVAPS is used as a ventilatory strategy.

Acute hypercapnic respiratory failure and its management on the acute medical take

Acute hypercapnic respiratory failure accounts for 50 000 hospital admissions each year in the UK. This article discusses the pathophysiology and common causes of acute hypercapnic respiratory failure, and provides practical considerations for patient management in acute medical settings. Non-invasive ventilation for persistent acute hypercapnic respiratory failure is widely recognised to improve patient outcomes and reduce mortality. National audits highlight a need to improve patients' overall care and outcomes through appropriate patient selection and treatment initiation. Multidisciplinary involvement is essential, as this underpins inpatient care and follow up after hospital discharge. New non-invasive ventilation modalities may offer better patient comfort and compensate better for sleep-related changes in respiratory mechanics. Emerging therapies, such as nasal high flow, may offer an alternative treatment approach in those who cannot tolerate non-invasive ventilation, but more research is required to completely understand its effectiveness in treating acute hypercapnic respiratory failure.

P136 Domiciliary Bilevel Ventilation at Sunshine Coast University Hospital

Introduction Positive airway pressure therapy, including bilevel (BPAP) and continuous positive airway pressure (CPAP), is the mainstay of management of a group of chronic conditions that culminate in chronic hypercapnic respiratory failure such as chronic obstructive pulmonary disease (COPD), obesity hypoventilation syndrome (OHS) and respiratory muscle weakness. Heterogeneously across these conditions, BPAP can decrease hospital admission and prolong quality and duration of life. In COPD (when with comorbid obstructive sleep apnoea) and OHS, there has been some evidence to suggest that the far more economical CPAP is as effective. Here we compare local practice to guideline suggested management and previous Australasian audit data. Methods Adult patients currently managed with domiciliary BPAP by the SCUH Sleep Department were identified from local a database. Demographics, medical diagnoses, premorbid functional status, indications for BPAP, funding of BPAP, outcomes of therapy and attempts to de-escalate to CPAP were collected. Results 64 patient were identified. Data collection and analysis is ongoing and will be presented at full at the conference. Intended Outcome and Impact: We aim to review local practice managing chronic hypercapnic respiratory failure with BPAP with hope it could inform future local practice.