http://orcid.org/0000-0003-3598-3986
ABSTRACT
Non-invasive ventilation (NIV) has been recommended as the first-line ventilation modality for acute respiratory failure (ARF) due to acute exacerbation of chronic obstructive pulmonary disease (AECOPD) based on strong evidence. However, everyday clinical practice may differ from findings of multiple randomized controlled trials. Physicians and respiratory therapists involved in NIV management have been queried about its utilization and effectiveness. In addition to these estimates, cohort studies and analysis of large inpatient dataset of patients with AECOPD and ARF managed with NIV have been extensively published over the last two decades. This review summarizes the perception of medical staff vs. the “real life” data about NIV use for ARF in AECOPD patients.
Introduction
Chronic obstructive pulmonary disease (COPD) is a relatively prevalent lung disease with a global prevalence of 12% and is one of the leading causes of morbidity and mortality worldwide Citation(1–4). Acute exacerbation of COPD (AECOPD), associated with a significant change in pulmonary mechanics that is almost fully reversed in the recovery period Citation(5), is the third common etiology in medical patients hospitalized because of acute respiratory failure (ARF). The need for any kind of ventilator support has increased over the years, with a significant shift toward greater use of non-invasive ventilation (NIV) at the expense of invasive mechanical ventilation (IMV) in this group of patients Citation(6–9).
Multiple randomized controlled trials and four meta-analyses demonstrated that NIV reduces the intubation and accordingly mortality rates, as well as length of hospital and intensive care unit (ICU) stay in patients with acute or acute-on-chronic respiratory failure (AOCRF) due to AECOPD Citation(10–13). As a result, the recently published European Respiratory Society and American Thoracic Society joint guideline as well as British Thoracic Society and Intensive Care Society guideline and Global Initiative for Chronic Lung Disease report recommend the use of NIV as a first-line treatment for patients with AECOPD and ARF Citation(14–16). It was described either as “protective” in patients with modest respiratory acidosis (preventing from deterioration and IMV), or as “alternative” to IMV in more severe cases (with lower pH or higher clinical respiratory distress) or as “ceiling” when patients are not candidates for IMV.
National and international surveys have been conducted among physicians (including both pulmonologists and other specialists), residents, respiratory therapists (RTs) and nurses to learn about their perception regarding characteristics of NIV utilization in the management of patients with ARF, including patients with AECOPD Citation(13, 17–32). Most of these surveys were carried out in the early 2000s. These surveys provided data, including estimates of NIV utilization and failure rates, barriers for its use, patient characteristics, equipment and settings of NIV, location of initiation/follow-up and technical and organizational aspects. However, what was the reality?
Despite the increased amount of scientific evidence over the last two decades, little was known about the NIV use in ARF due to AECOPD in the real world in the first decade of the 21st century Citation(33–39). But over the last few years, significant amount of data, regarding the use and outcomes of NIV as well as patient and hospital characteristics, emerged from mainly either administrative inpatient datasets or prospective/retrospective cohorts of this particular population Citation(6–9, 38, 40–57).
In this narrative review, the characteristics of NIV utilization for ARF due to AECOPD and its outcomes will be summarized based on the findings of above-mentioned surveys, population-based or observational cohort studies.
Results of national/international surveys
Among all the surveys, related to NIV use in AECOPD and published in the 21st century, findings of 12 studies are summarized in Citation(13, 17–30). NIV utilization population was selected as only AECOPD in three of these surveys Citation(17,19,22), while there were all ARF patients in the rest Citation(13, 18, 20, 21, 23–25, 27). The questionnaires were directed to the medical teams involved in the management of ARF, mainly physicians (pulmonologists, intensivists, anesthesiologists, internal and emergency medicine physicians) or RTs. Out of 12 surveys, three were international including physicians from Europe, North/South America, Asia, Africa or Oceania Citation(13, 24, 26).
Table 1. Results of survey studies regarding the use of NIV in AECOPD.
In one of the earlier surveys, the utilization rate was low among emergency departments (EDs) of Belgium, mainly due to lack of equipment Citation(17). In the following years, NIV availability was reported more in Canadian teaching hospitals, as well as increased utility (at most in patients with AECOPD), especially in monitored settings, such as ICU or EDs Citation(18,19). The utilization for AECOPD population varied extremely from sites reporting rare use to others where it was routine practice. Although the randomized controlled trials had shown effectiveness of NIV in decreasing intubation and mortality rates in AECOPD, 7% of the physicians were still questioning its benefits Citation(18).
The first survey about NIV use in the United States (US) was performed in acute care hospitals of Massachusetts and Rhode Island Citation(20). Based on the estimation of NIV use during the previous month as a % of total ventilator starts, the overall utilization rate was 20%, varying from none to over 50%. Although AECOPD and congestive heart failure accounted for a large majority (82%) of all applications of NIV, only 33% of the patients with AECOPD were reported to be initially treated with NIV. The next survey from academic EDs of the US showed an increase in the utilization rate with 66% of the respondents claiming NIV use for more than 20% of the cases with AECOPD Citation(31). The surprising finding of this study was that nearly one-fifth of the physicians and RTs still reported an estimated rate of NIV use less than 10% in AECOPD. Another survey from ICU teams of Veterans Affairs hospitals of the US noted that NIV was perceived as first-line treatment for AECOPD by 76% of the respondents Citation(23). However, the actual utilization rate when NIV was indicated was estimated to be lower than expected. In this survey, RTs reported more NIV underutilization and failure as compared to physicians.
In one of the international studies, Devlin et al. Citation(13) demonstrated the frequency of NIV among different causes of ARF. Forty-four percent of the physicians who were surveyed from North America and Europe estimated an overall NIV utilization >25% of all ARF patients, whereas 84% of the respondents for NIV use >25% of AECOPD. In general, Europeans were found to utilize NIV more than Americans. A large European web-based survey of NIV practices also showed a similar result of higher rate of perceived NIV use among pulmonologists, especially for patients with hypercapnic ARF, than among intensivists and emergency medicine physicians Citation(24). This can be due to the fact that most of the ICUs in Europe are run by anesthesiologists on the contrary to US ICUs by pulmonologists. Therefore, a European pulmonologist may be involved with the management of less severe patients, not requiring intubation at wards or intermediate care units/respiratory ICUs. In the latter trial, the overall NIV utilization rate was perceived as >20% of the patients for 81% of the respondents, and hypercapnic ARF was reported to be nearly half of all NIV use.
More recent studies revealed higher estimates of NIV use and success rates in AECOPD Citation(27, 28) as compared to earlier studies Citation(13, 23). These higher rates can be due to more appropriate applications of NIV with more experienced medical staff. Majority of the respondents of a Turkish survey reported general wards as the site for NIV applications for AECOPD. Similarly, in an international survey, including a limited number of hospitals from five continents and focusing on NIV for ARF in general non-monitored wards, AECOPD was shown to be the most common indication of NIV use (94%) outside the ICU. Although patients can be extensively monitored in ICUs' “safe” environment, shortage of intensive care beds, managing less severe cases of ARF in other units, increased experience and evidence in the use of NIV outside the ICU may have led to this trend Citation(28).
“Dedicated ventilators” for acute NIV with a full-face mask were most often preferred by European physicians for AECOPD management Citation(24), which was in accordance with general NIV equipment used for all patients with ARF Citation(23, 24). These ventilators have the capability of leak compensation. However in countries with lower socio-economic status, “home-care” ventilators were stated as the preferred choice of ventilators Citation(28).
Although surveys bring out the perception of medical teams about NIV use in AECOPD, there are several limitations which deserve a mention. The response rates of the surveys are between 22% and 100%. Therefore, the results may not reflect the approach of non-respondents to NIV use. A selection bias, favoring NIV-utilizing physicians to respond, may occur. It is difficult to extrapolate the results of these surveys to the whole clinical practice, since there is great variation between different hospitals, or geographic areas Citation(13, 18, 19, 26, 28). This variation can be due to physician (e.g., experience), hospital (e.g., teaching status, availability of trained staff with adequate equipment, etc.) or patient (e.g., severity of AECOPD) related factors. Last but not the least, stated practice may differ from actual practice.
Results of analysis of inpatient datasets or observational cohort studies
Findings of the analysis of inpatient datasets and observational cohort studies reflect the actual NIV practice in the real life. The retrospective analysis of inpatient datasets from a large number of hospitals, mainly from the US, covering for a long period of time can provide considerable data about NIV management in patients hospitalized because of AECOPD. But the results may not be entirely generalizable, since those datasets were mainly voluntary, fee-supported and regional. Those analyses mainly rely on the International Statistical Classification of Disorders (ICD) coding for case identification and type mechanical ventilation use; therefore, there might be misclassification of patients. To overcome this limitation, a verification, by, for example, questioning the steroid/antibiotic use or by searching the RT records, might be necessary Citation(7, 41, 43, 55). Determining the sequence of NIV and IMV can be challenging, whether it is intubation as a result of NIV failure or NIV use after extubation Citation(8, 41). Another limitation of these studies is the lack of physiologic data, information about advance directives of patients and location of NIV applications, all of which can influence the NIV outcomes Citation(58). On the other hand, while observational cohort studies can provide data about severity and acuity of the illness and the patient or location of NIV management, the information can be limited to a single center or region with a less number of patients enrolled compared to prior type of studies Citation(46, 49, 50). For both, the decision of NIV initiation or intubation as a result of NIV failure cannot be controlled. Besides all these limitations, the information regarding the characteristics of NIV management in patients with AECOPD, which mainly emerged in the last decade, is tremendous Citation(6–9, 38–57) ().
Table 2. Results of studies analyzing: (a) inpatient datasets regarding the use of NIV in AECOPD and (b) observational cohorts regarding the use of NIV in AECOPD (published in last decade).
Table 2. (Continued)
NIV utilization
In the past two decades, the use of NIV for AECOPD has increased over the years globally. The first epidemiologic studies regarding this were mainly from ICUs, where most of the prior randomized controlled trials took place Citation(59–61). Girou et al. Citation(35) reported a progressive increase in the utilization of NIV for ARF due to COPD and cardiogenic pulmonary edema (from 20% of ventilator starts in 1994 to nearly 90% in 2001) in a single French ICU. A subsequent international study conducted in 361 ICUs of 20 countries demonstrated an incline of NIV use for AECOPD from 16% in 1998 to 44% in 2004 Citation(37). Three serial prospective audits were conducted in >40 French ICUs in 1997, 2002 and 2010/2011 Citation(33, 36, 52). Overall NIV use as first-line modality of ventilation was shown to increase from 16% to 23% first, but then reached a plateau of 24%, in parallel to its use for AOCRF (50%, 64% and 65%, respectively). These rates are low for AECOPD as opposed to its efficiency; however, that result could be due to higher severity of patients in ICUs compared to other units or use of NIV before ICU admission Citation(62). As highlighted by the authors, it is important to put further efforts promoting NIV for this particular indication Citation(52).
Evidence of benefits of NIV for ARF due to AECOPD has accrued, not only for patients managed in ICUs, but also out of the ICU Citation(63–65). In a prospective cohort of all ventilated patients with ARF conducted between 2004 and 2007 in ICUs, EDs and general wards of eight acute care hospitals of Massachusetts and Rhode Island, five of which were estimated to have a NIV utilization rate of <20% in a prior survey mentioned earlier Citation(20), the overall NIV initiation rate was 38.5%, with a range of 23.9–72% between hospitals Citation(49). While this rate for AECOPD was estimated as 33% by the survey conducted 3–4 years before, the actual rate demonstrated by the cohort study was 82%. This significant increase can be a result of substantial amount of experience gained over the years with increasing evidence of efficient NIV use for ARF due to AECOPD or can be a reflection of negative perception of RTs about NIV in the prior survey, but its similarity to the estimation of Biererer et al. reported in the same time frame (78%) supports the former reason (Citation23).
An analysis of large US-based inpatient databases reflects these trends Citation(6, 7, 38, 40). The first analysis performed by Chandra et al. Citation(6) in over 7.5 million hospitalized patients with AECOPD using the nationwide inpatient sample (NIS) showed a fourfold increase in NIV use in 10 years. Stefan et al. Citation(7) applied a more sensitive approach for patient enrollment and identification of NIV use, therefore demonstrating a higher rate of NIV initiation of 59% of all ventilator starts [vs. 38% as reported by Chandra et al. Citation(6)]. The rates varied enormously among the centers Citation(40, 43). The increase in NIV use as the first-line ventilation modality was offset by the decrease in IMV use () Citation(7, 43). Since there was also an incline in the rate of mechanical ventilation, it can be suggested that NIV was increasingly used as an “alternative” to intubation. However without knowledge of severity of ARF mainly based on physiologic data, it is difficult to determine definitely whether the threshold for NIV applications has changed over time or not.
Figure 1. Trends in initial ventilation strategies among patients with ARF due to AECOPD. IMV, invasive mechanical ventilation; MV, mechanical ventilation; NIV, non-invasive ventilation. Reprinted from Stefan et al. Citation(7). Copyright (2017), with permission from Elsevier.
Patient and hospital characteristics
Patient factors associated with NIV start for AECOPD as compared to IMV start were listed as older age, less co-morbidity, lack of pneumonia, lower simplified acute physiology score (SAPS) II, presence of advance directives (such as do-not-resuscitate order), more ED admissions or previous admission for AECOPD Citation(6, 7, 39, 41, 42). On the other hand, there are some conflicting findings about the hospital characteristics of frequent NIV users based on different databases Citation(40, 43, 55). While some reported associations with higher volume of AECOPD and ARF as well as higher volume of total NIV use for ARF (including COPD and non-COPD causes), especially rural hospitals and the ones in the northeast of US Citation(40, 55), one study demonstrated that lower annual AECOPD case volume was more common for frequent NIV initiation Citation(43). However in the latter analysis, the frequency was defined by adjustments for patient demographics, co-morbidity score, prior COPD admission and presence of pneumonia, possibly leading to this result; therefore, it is important to note the different statistical analyses while reading the results.
NIV failure
NIV failure was defined mostly as an intubation following a period of NIV, when clinical or physiologic response is inadequate or deteriorating, while discontinuation of NIV due to mask intolerance, complications or death was also included in the definition of some Citation(49, 52). Actual rate of NIV failure for ARF due to AECOPD was around 16%, lower than the estimates of the surveys Citation(24, 27). Chandra et al. Citation(6) reported a much lower rate of 5%, possibly due to the enrollment of patients with do-not-intubate order, discontinuation of NIV due to death of the patient or a perfect selection of appropriate patients for NIV applications.
The predictors of NIV failure among AECOPD patients were reported as higher SAPS II and acute organ failure scores at admission as well as the presence of more co-morbidities (>4, including especially pneumonia and cancer) Citation(7,40–42). This was in accordance with earlier studies Citation(58). On the other hand, NIV failure was associated with higher rates of in-hospital mortality and length of stay (LOS), as well as costs Citation(6, 8, 38, 40, 42, 48–51). Increased mortality in case of NIV failure can be due to application of NIV in patients more difficult to ventilate (for example with higher SAPS II scores (Citation47) or co-morbidities like pneumonia), insistence on NIV management with a lack of early improvement or both. Although NIV can be initiated as an “alternative” to IMV, it does not replace IMV. NIV should better be used cautiously in high-risk patients for NIV failure in monitored environment with trained medical staff, with urgent intubation in case there is no improvement or deterioration in clinical or physiological findings in first 1–2 hours of NIV trial.
Mortality and other NIV outcomes
In-hospital mortality rate among NIV users for AECOPD was reported as 6.5% in a recent study by Stefan et al. Citation(55) The risk-adjusted mortality rate decreased substantially over time Citation(45). In addition to NIV failure, the presence of ventilator-associated pneumonia or cardiovascular co-morbidities was listed as predictors of mortality Citation(48, 50), whereas first-line NIV use was associated with a lower rate of fatal outcome, besides lower LOS, cost and complications (ventilator associated pneumonia and iatrogenic pneumothorax) Citation(40–43).
Caring for higher number of patients may develop local expertise (practice makes perfect), and conversely, experienced centers receive many referrals from other hospitals. This can lead to better NIV outcomes, as shown by Dres et al. Citation(47) with a lower rate of NIV failure and mortality in cohort of patients with AECOPD admitted to 35 French ICUs between 1998 and 2010. However, two studies with an analysis of two different inpatient datasets conflicted with this, one demonstrating no association of NIV case volume with NIV failure, mortality, LOS and re-admission of AECOPD patients Citation(55), whereas another displaying even more NIV failure (associated with higher mortality) in higher NIV users Citation(44). The quartile ranges for NIV case volume differed between studies [e.g., 2–43 Citation(44) vs. 53–368 Citation(55) patients for lowest quartile], probably leading to this difference in association. Apart from this, since a tendency to use NIV in patients with more co-morbidities (including pneumonia) and acute organ failures was reported Citation(7) (), higher rates of worse outcomes can be due to the approach of experienced physicians, possibly over-utilizing NIV for risky patients.
Figure 2. Trends in ventilation use in COPD with and without pneumonia, 2001–2011. (A) Any ventilation. (B) Non-invasive ventilation. (C) Invasive ventilation. Reprinted from Stefan et al. Citation(7). Copyright (2017), with permission from Elsevier.
Technical aspects
Either critical care or bi-level-type pressure-limited ventilators (hospital or home type) can be used to administer NIV; no study demonstrated any superiority of one over other. While ICU ventilators remained the most widely used devices in the French cohort from ICUs Citation(52), bi-level ventilators were preferred by US physicians in and out of the ICUs Citation(49). In accordance with the survey studies, full-face masks were the most commonly used mask types for NIV initiation Citation(49, 52).
Conclusion
Since 1990s, robust data emerged continuously about efficacy of NIV management in reducing the intubation and the mortality rates in patients with AECOPD. Although the estimates of utilization and success rates were quite low at the beginning of the 21st century, the data published especially in the last decade demonstrated the expanding actual use of NIV, in expense of IMV. This dramatic increase was probably due to increased experience of the medical teams, even treating sicker patients with co-morbidities decreasing the benefits of NIV, and utilization of NIV outside the ICU. However, there is still space for further utilization. But while promoting this, it should be emphasized that risky patients should be closely monitored, since NIV failure can lead to increased mortality.
Abbreviations
| AECOPD | = | Acute exacerbation of chronic obstructive pulmonary disease |
| AOCRF | = | Acute-on-chronic respiratory failure |
| ARF | = | Acute respiratory failure |
| COPD | = | Chronic obstructive pulmonary disease |
| DNI | = | Do-not-intubate |
| ED | = | Emergency department |
| HDU | = | High dependency unit |
| ICD | = | International Statistical Classification of Disorders |
| ICU | = | Intensive care unit |
| IMV | = | Invasive mechanical ventilation |
| LOS | = | Length of stay |
| NIS | = | Nationwide inpatient sample |
| NIV | = | Non-invasive ventilation |
| RT | = | Respiratory therapist |
| SAPS | = | Simplified acute physiology score |
Declaration of interest
The authors have declared that no competing interests exist.
References
- Vos T, Flaxman AD, Naghavi M, Lozano R, Michaud C, Ezzati M, et al. Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012;380:2163–2196.
- Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, et al. Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012;380:2095–2128.
- National Center for Health Statistics. Health, United States 2015 with Special Feature on Racial and Ethnic Health Disparities. Hyattsville, MD: US Dept Health and Human Services; 2016.
- Adeloye D, Chua S, Lee C, Basquill C, Papana A, Theodoratou E, et al. Global and regional estimates of COPD prevalence: Systematic review and meta-analysis. J Glob Health 2015;5:020415.
- Ceriana P, Vitacca M, Carlucci A, Paneroni M, Pisani L, Nava S. Changes of respiratory mechanics in COPD patients from stable state to acute exacerbations with respiratory failure. COPD 2016;14:150–155.
- Chandra D, Stamm JA, Taylor B, Ramos RM, Satterwhite L, Krishnan JA, et al. Outcomes of noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease in the United States, 1998–2008. Am J Respir Crit Care Med 2012;185:152–159.
- Stefan MS, Shieh MS, Pekow PS, Hill N, Rothberg MB, Lindenauer PK. Trends in mechanical ventilation among patients hospitalized with acute exacerbations of COPD in the United States, 2001 to 2011. Chest 2015;147(4):959–968.
- Toft-Petersen AP, Torp-Pedersen C, Weinreich UM, Rasmussen BS. Trends in assisted ventilation and outcome for obstructive pulmonary disease exacerbations. A nationwide study. PLoS One 2017;12:e0171713.
- Stefan MS, Shieh MS, Pekow PS, Rothberg MB, Steingrub JS, Lagu T, et al. Epidemiology and outcomes of acute respiratory failure in the United States, 2001 to 2009: a national survey. J Hosp Med 2013;8:76–82.
- Ram FS, Picot J, Lightowler J, Wedzicha JA. Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2004:CD004104.
- Quon BS, Gan WQ, Sin DD. Contemporary management of acute exacerbations of COPD: a systematic review and metaanalysis. Chest 2008;133:756–766.
- Burns KE, Meade MO, Premji A, Adhikari NK. Noninvasive positive-pressure ventilation as a weaning strategy for intubated adults with respiratory failure. Cochrane Database Syst Rev 2013:CD004127.
- Devlin JW, Nava S, Fong JJ, Bahhady I, Hill NS. Survey of sedation practices during noninvasive positive-pressure ventilation to treat acute respiratory failure. Crit Care Med 2007;35:2298–2302.
- Wedzicha JA, Miravitlles M, Hurst JR, Calverley PM, Albert RK, Anzueto A, et al. Management of COPD exacerbations: a European Respiratory Society/American Thoracic Society guideline. Eur Respir J 2017;49.
- Global Initiative for Chronic Obstructive Lung Diseases. Global strategy for the diagnosis, management and prevention of chronic obstructive pulmonary disease Global Initiative for Chronic Obstructive Lung Diseases, Inc., 2017. Available from http://goldcopd.org.
- Davidson AC, Banham S, Elliott M, Kennedy D, Gelder C, Glossop A, et al. BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults. Thorax 2016;71 Suppl 2:ii1–35.
- Vanpee D, Delaunois L, Lheureux P, Thys F, Sabbe M, Meulemans A, et al. Survey of non-invasive ventilation for acute exacerbation of chronic obstructive pulmonary disease patients in emergency departments in Belgium. Eur J Emerg Med 2002;9:217–224.
- Burns KE, Sinuff T, Adhikari NK, Meade MO, Heels-Ansdell D, Martin CM, et al. Bilevel noninvasive positive pressure ventilation for acute respiratory failure: survey of Ontario practice. Crit Care Med 2005;33:1477–1483.
- Drummond J, Rowe B, Cheung L, Mayers I. The use of noninvasive mechanical ventilation for the treatment of acute exacerbations of chronic obstructive pulmonary disease in Canada. Can Respir J 2005;12:129–133.
- Maheshwari V, Paioli D, Rothaar R, Hill NS. Utilization of noninvasive ventilation in acute care hospitals: a regional survey. Chest 2006;129:1226–1233.
- Browning J, Atwood B, Gray A. Use of non-invasive ventilation in UK emergency departments. Emerg Med J 2006;23:920–921.
- Stone RA, Harrison BD, Lowe D, Buckingham RJ, Pursey NA, Hosker HS, et al. Introducing the national COPD resources and outcomes project. BMC Health Serv Res 2009;9:173.
- Bierer GB, Soo Hoo GW. Noninvasive ventilation for acute respiratory failure: a national survey of Veterans Affairs hospitals. Respir Care 2009;54:1313–1320.
- Crimi C, Noto A, Princi P, Esquinas A, Nava S. A European survey of noninvasive ventilation practices. Eur Respir J 2010;36:362–369.
- Cabrini L, Antonelli M, Savoia G, Landriscina M. Non-invasive ventilation outside of the Intensive Care Unit: an Italian survey. Minerva Anestesiol 2011;77:313–322.
- Cabrini L, Esquinas A, Pasin L, Nardelli P, Frati E, Pintaudi M, et al. An international survey on noninvasive ventilation use for acute respiratory failure in general non-monitored wards. Respir Care 2015;60:586–592.
- Chawla R, Sidhu US, Kumar V, Nagarkar S, Brochard L. Noninvasive ventilation: a survey of practice patterns of its use in India. Indian J Crit Care Med 2008;12:163–169.
- Ozsancak Ugurlu A, Ergan B, Berk Takir H, In E, Ozyilmaz E, Ertan Edipoglu O, et al. Approach of pulmonologists in Turkey to noninvasive mechanical ventilation use in acute respiratory failure. Tuberk Toraks 2015;63:213–225.
- Cabrini L, Monti G, Villa M, Pischedda A, Masini L, Dedola E, et al. Non-invasive ventilation outside the Intensive Care Unit for acute respiratory failure: the perspective of the general ward nurses. Minerva Anestesiol 2009;75:427–433.
- Salvade I, Domenighetti G, Jolliet P, Maggiorini M, Rothen HU. Perception of non-invasive ventilation in adult Swiss intensive care units. Swiss Med Wkly 2012;142:w13551.
- Hess DR, Pang JM, Camargo CA, Jr. A survey of the use of noninvasive ventilation in academic emergency departments in the United States. Respir Care 2009;54:1306–1312.
- Doherty MJ, Greenstone MA. Survey of non-invasive ventilation (NIPPV) in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) in the UK. Thorax 1998;53:863–866.
- Carlucci A, Richard JC, Wysocki M, Lepage E, Brochard L. Noninvasive versus conventional mechanical ventilation. An epidemiologic survey. Am J Respir Crit Care Med 2001;163:874–880.
- Carlucci A, Delmastro M, Rubini F, Fracchia C, Nava S. Changes in the practice of non-invasive ventilation in treating COPD patients over 8 years. Intensive Care Med 2003;29:419–425.
- Girou E, Brun-Buisson C, Taille S, Lemaire F, Brochard L. Secular trends in nosocomial infections and mortality associated with noninvasive ventilation in patients with exacerbation of COPD and pulmonary edema. JAMA 2003;290:2985–2991.
- Demoule A, Girou E, Richard JC, Taille S, Brochard L. Increased use of noninvasive ventilation in French intensive care units. Intensive Care Med 2006;32:1747–1755.
- Esteban A, Ferguson ND, Meade MO, Frutos-Vivar F, Apezteguia C, Brochard L, et al. Evolution of mechanical ventilation in response to clinical research. Am J Respir Crit Care Med 2008;177:170–177.
- Walkey AJ, Wiener RS. Use of noninvasive ventilation in patients with acute respiratory failure, 2000–2009: a population-based study. Ann Am Thorac Soc 2013;10:10–17.
- Kaul S, Pearson M, Coutts I, Lowe D, Roberts M. Non-invasive ventilation (NIV) in the clinical management of acute COPD in 233 UK hospitals: results from the RCP/BTS 2003 National COPD Audit. COPD 2009;6:171–176.
- Tsai CL, Lee WY, Delclos GL, Hanania NA, Camargo CA, Jr. Comparative effectiveness of noninvasive ventilation vs invasive mechanical ventilation in chronic obstructive pulmonary disease patients with acute respiratory failure. J Hosp Med 2013;8:165–172.
- Lindenauer PK, Stefan MS, Shieh MS, Pekow PS, Rothberg MB, Hill NS. Outcomes associated with invasive and noninvasive ventilation among patients hospitalized with exacerbations of chronic obstructive pulmonary disease. JAMA Intern Med 2014;174:1982–1993.
- Stefan MS, Nathanson BH, Higgins TL, Steingrub JS, Lagu T, Rothberg MB, et al. Comparative effectiveness of noninvasive and invasive ventilation in critically ill patients with acute exacerbation of chronic obstructive pulmonary disease. Crit Care Med 2015;43:1386–1394.
- Lindenauer PK, Stefan MS, Shieh MS, Pekow PS, Rothberg MB, Hill NS. Hospital patterns of mechanical ventilation for patients with exacerbations of COPD. Ann Am Thorac Soc 2015;12:402–409.
- Mehta AB, Douglas IS, Walkey AJ. Hospital noninvasive ventilation case volume and outcomes of acute exacerbations of chronic obstructive pulmonary disease. Ann Am Thorac Soc 2016;13:1752–1759.
- Funk GC, Bauer P, Burghuber OC, Fazekas A, Hartl S, Hochrieser H, et al. Prevalence and prognosis of COPD in critically ill patients between 1998 and 2008. Eur Respir J 2013;41:792–799.
- Wang S, Singh B, Tian L, Biehl M, Krastev IL, Kojicic M, et al. Epidemiology of noninvasive mechanical ventilation in acute respiratory failure—a retrospective population-based study. BMC Emerg Med 2013;13:6.
- Dres M, Tran TC, Aegerter P, Rabbat A, Guidet B, Huchon G, et al. Influence of ICU case-volume on the management and hospital outcomes of acute exacerbations of chronic obstructive pulmonary disease. Crit Care Med 2013;41:1884–1892.
- Schnell D, Timsit JF, Darmon M, Vesin A, Goldgran-Toledano D, Dumenil AS, et al. Noninvasive mechanical ventilation in acute respiratory failure: trends in use and outcomes. Intensive Care Med 2014;40:582–591.
- Ozsancak Ugurlu A, Sidhom SS, Khodabandeh A, Ieong M, Mohr C, Lin DY, et al. Use and outcomes of noninvasive positive pressure ventilation in acute care hospitals in Massachusetts. Chest 2014;145:964–971.
- Ouanes I, Ouanes-Besbes L, Ben Abdallah S, Dachraoui F, Abroug F. Trends in use and impact on outcome of empiric antibiotic therapy and non-invasive ventilation in COPD patients with acute exacerbation. Ann Intensive Care 2015;5:30.
- Gacouin A, Jouneau S, Letheulle J, Kerjouan M, Bouju P, Fillatre P, et al. Trends in prevalence and prognosis in subjects with acute chronic respiratory failure treated with noninvasive and/or invasive ventilation. Respir Care 2015;60:210–218.
- Demoule A, Chevret S, Carlucci A, Kouatchet A, Jaber S, Meziani F, et al. Changing use of noninvasive ventilation in critically ill patients: trends over 15 years in francophone countries. Intensive Care Med 2016;42:82–92.
- Liu J, Duan J, Bai L, Zhou L. Noninvasive ventilation intolerance: characteristics, predictors, and outcomes. Respir Care 2016;61:277–284.
- Cabrini L, Landoni G, Oriani A, Plumari VP, Nobile L, Greco M, et al. Noninvasive ventilation and survival in acute care settings: a comprehensive systematic review and metaanalysis of randomized controlled trials. Crit Care Med 2015;43:880–888.
- Stefan MS, Pekow PS, Shieh MS, Hill NS, Rothberg MB, Fisher KA, et al. Hospital volume and outcomes of noninvasive ventilation in patients hospitalized with an acute exacerbation of chronic obstructive pulmonary disease. Crit Care Med 2017;45:20–27.
- Roberts CM, Stone RA, Buckingham RJ, Pursey NA, Lowe D. Acidosis, non-invasive ventilation and mortality in hospitalised COPD exacerbations. Thorax 2011;66:43–48.
- George PM, Stone RA, Buckingham RJ, Pursey NA, Lowe D, Roberts CM. Changes in NHS organization of care and management of hospital admissions with COPD exacerbations between the national COPD audits of 2003 and 2008. QJM 2011;104:859–866.
- Ozyilmaz E, Ugurlu AO, Nava S. Timing of noninvasive ventilation failure: causes, risk factors, and potential remedies. BMC Pulm Med 2014;14:19.
- Brochard L, Mancebo J, Wysocki M, Lofaso F, Conti G, Rauss A, et al. Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease. N Engl J Med 1995;333:817–822.
- Celikel T, Sungur M, Ceyhan B, Karakurt S. Comparison of noninvasive positive pressure ventilation with standard medical therapy in hypercapnic acute respiratory failure. Chest 1998;114:1636–1642.
- Conti G, Antonelli M, Navalesi P, Rocco M, Bufi M, Spadetta G, et al. Noninvasive vs. conventional mechanical ventilation in patients with chronic obstructive pulmonary disease after failure of medical treatment in the ward: a randomized trial. Intensive Care Med 2002;28:1701–1707.
- Ozsancak Ugurlu A, Sidhom SS, Khodabandeh A, Ieong M, Mohr C, Lin DY, et al. Where is noninvasive ventilation actually delivered for acute respiratory failure? Lung 2015;193:779–788.
- Plant PK, Owen JL, Elliott MW. Early use of non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease on general respiratory wards: a multicentre randomised controlled trial. Lancet 2000;355:1931–1935.
- Farha S, Ghamra ZW, Hoisington ER, Butler RS, Stoller JK. Use of noninvasive positive-pressure ventilation on the regular hospital ward: experience and correlates of success. Respir Care 2006;51:1237–1243.
- Schneider AG, Calzavacca P, Mercer I, Hart G, Jones D, Bellomo R. The epidemiology and outcome of medical emergency team call patients treated with non-invasive ventilation. Resuscitation 2011;82:1218–1223.