Noninvasive Ventilation Is More Effective Than Invasive Mechanical Ventilation for Acute Exacerbations of COPD but Remains Under-Utilized
Noninvasive Ventilation Is More Effective Than Invasive Mechanical Ventilation for Acute Exacerbations of COPD but Remains Under-Utilized
Abstract & Commentary
By Kenneth P. Steinberg, MD, FACP, Professor, University of Washington School of Medicine, Seattle, WA, Editor of Hospital Medicine Alert.
Synopsis: Noninvasive ventilation has previously been shown to improve outcomes in studies of patients with acute respiratory failure secondary to an acute exacerbation of COPD. This study confirms the effectiveness of noninvasive ventilation in a large population-based registry and also demonstrates the wide variability of implementation and significant under-utilization of this therapy.
Source: Tsai CL, et al. Comparative effectiveness of noninvasive ventilation vs invasive mechanical ventilation in chronic obstructive pulmonary disease patients with acute respiratory failure. J Hospital Med 2013; 8:165–172.
Noninvasive ventilation (NIV), referring to positive-pressure ventilatory support delivered via a nasal or full-face mask, has emerged as a useful treatment modality in patients with AECOPD and acute respiratory failure. Much of the literature suggests a mortality benefit with NIV compared with standard medical care in AECOPD. These data were collected in small-to-moderate sized research studies with many inclusion and exclusion criteria while only a few small, randomized controlled trials have directly compared NIV to invasive mechanical ventilation. The authors wished to better understand the adoption and effectiveness of NIV treatment for AECOPD in the “real-world” setting; their stated goals were (1) to characterize the use of NIV and invasive mechanical ventilation in AECOPD patients with acute respiratory failure; and (2) to compare the effectiveness of NIV vs invasive mechanical ventilation in daily practice.
The study was a retrospective cohort design using data from the 2006–2008 Nationwide Emergency Department Sample (NEDS), a component of the Healthcare Cost and Utilization Project sponsored by the Agency for Healthcare Research and Quality. The NEDS is nationally representative of all community hospital-based EDs in the United States. Patient visits were identified for this analysis if they carried any COPD-related diagnostic code as their primary or secondary ED diagnosis and any acute respiratory failure code as a primary or secondary diagnosis.
To compare the effectiveness of different ventilatory modes, patients were divided into 3 groups according to the ventilation mode they received: (1) NIV alone, (2) invasive mechanical ventilation alone, and (3) combined modes of NIV and invasive mechanical ventilation. Outcome measures were all-cause inpatient mortality, hospital LOS, hospital charges, and ventilator-related complications.
There were an estimated 101,000 visits annually for AECOPD with acute respiratory failure from approximately 4,700 US EDs. The mean patient age was 68 years. Ninety-six percent were admitted to the hospital. The mortality rate for those admitted was 9%, and the mean hospital LOS was 7 days. The use of invasive mechanical ventilation decreased from 28% in 2006 to 19% in 2008 (P<0.001), whereas NIV use increased slightly from 14% in 2006 to 16% in 2008 (P=0.049); the combined use of both ventilation modalities remained stable (approximately 4%). Inpatient mortality decreased from 10% in 2006 to 7% in 2008 (P<0.001).
The frequency of NIV use varied widely between hospitals, ranging from 0% to 100% with a median of 11%. In the cohort of AECOPD with acute respiratory failure, 43% received some form of ventilatory support: 36% received NIV, 56% received invasive mechanical ventilation, and 8% received combined use. Patients who received the combined use of NIV and invasive mechanical ventilation tended to have other comorbidities (congestive heart failure and pneumonia) compared with the NIV-alone or invasive mechanical ventilation-alone groups. NIV was used more often in hospitals with higher volumes of AECOPD and respiratory failure, in nonmetropolitan hospitals, and in hospitals in the Northeast.
In the propensity score-matched cohort, NIV use remained associated with significantly lower inpatient mortality (risk ratio: 0.54; 95% CI: 0.50-0.59, P<0.001), a shorter hospital LOS (mean difference, -3.2 days; 95% CI: -3.4 to -2.9 days, P<0.001), and lower hospital charges (mean difference, P<$35,012; 95% CI: -$36,848 to -$33,176, P<0.001), compared with invasive mechanical ventilation. Use of NIV was also associated with a lower rate of iatrogenic pneumothorax than invasive mechanical ventilation use (0.05% vs 0.5%, P<0.001).
Commentary
One of the strengths of this study is its use of a large national database that is representative of community hospital-based EDs across the United States. The study found that NIV use for acute respiratory failure from AECOPD, compared to invasive mechanical ventilation, was associated with a significant reduction of inpatient mortality, hospital LOS, hospital charges, and a modestly reduced risk of iatrogenic pneumothorax. As an analysis of an administrative database, and thus an observational study, the major limitations of the study include an inability to assume causality from the associations, and the possibility of unrecognized and unaccounted for confounding. Nevertheless, the findings are plausible based on the existing literature. That, plus the size of the database, makes the results more compelling.
There is some good news in this study: the use of NIV is rising, albeit modestly, and the use of invasive mechanical ventilation is decreasing. Mortality is also decreasing over time. But the disheartening news was that utilization of NIV remained very low (only 16% in 2008) and varied widely by patient and hospital characteristic. This is clearly an opportunity for improvement!
There are well-recognized contraindications to NIV, thus not every patient is a candidate for this treatment. Yet for good candidates, the use of NIV for acute respiratory failure secondary to AECOPD is not easy. Many systems-level barriers exist despite the demonstrated efficacy of NIV including lack of physician knowledge, insufficient respiratory therapist staffing and/or training, insufficient numbers of NIV machines in a given hospital, and the amount of time available to safely and effectively set up NIV. It requires time and patience to fit a mask properly and adjust the settings so that the therapy is well tolerated. It is easier and faster to sedate and intubate a patient presenting with acute respiratory failure from AECOPD. Yet expediency, often a virtue, does not always lead to the best outcomes for this illness.
In summary, in this nationally representative database, NIV use is increasing for AECOPD with acute respiratory failure; however, its adoption remains low and varies widely between U.S. hospitals. NIV appears to be more effective and safer than invasive mechanical ventilation in the real-world setting. I believe that hospitalists can play an important role advocating for the increased use of NIV in their hospitals and promoting the use of NIV in patients with severe AECOPD.
Noninvasive ventilation has previously been shown to improve outcomes in studies of patients with acute respiratory failure secondary to an acute exacerbation of COPD. This study confirms the effectiveness of noninvasive ventilation in a large population-based registry and also demonstrates the wide variability of implementation and significant under-utilization of this therapy.Subscribe Now for Access
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