Bilevel noninvasive positive pressure ventilation for acute respiratory failure: Survey of Ontario practice*

[Non-invasive Mechanical Ventilation in Acute Respiratory Failure. Clinical Practice Guidelines - on behalf of the German Society of Pneumology and Ventilatory Medicine]

The guideline update outlines the advantages as well as the limitations of NIV in the treatment of acute respiratory failure in daily clinical practice and in different indications.Non-invasive ventilation (NIV) has a high value in therapy of hypercapnic acute respiratory failure, as it significantly reduces the length of ICU stay and hospitalization as well as mortality.Patients with cardiopulmonary edema and acute respiratory failure should be treated with continuous positive airway pressure (CPAP) and oxygen in addition to necessary cardiological interventions. This should be done already prehospital and in the emergency department.In case of other forms of acute hypoxaemic respiratory failure with only mild or moderately disturbed gas exchange (PaO2/FiO2 > 150 mmHg) there is no significant advantage or disadvantage compared to high flow nasal oxygen (HFNO). In severe forms of ARDS NIV is associated with high rates of treatment failure and mortality, especially in cases with NIV-failure and delayed intubation.NIV should be used for preoxygenation before intubation. In patients at risk, NIV is recommended to reduce extubation failure. In the weaning process from invasive ventilation NIV essentially reduces the risk of reintubation in hypercapnic patients. NIV is regarded useful within palliative care for reduction of dyspnea and improving quality of life, but here in concurrence to HFNO, which is regarded as more comfortable. Meanwhile NIV is also recommended in prehospital setting, especially in hypercapnic respiratory failure and pulmonary edema.With appropriate monitoring in an intensive care unit NIV can also be successfully applied in pediatric patients with acute respiratory insufficiency.

Hospital Variation in Non-Invasive Ventilation Use for Acute Respiratory Failure Due to COPD Exacerbation

Background

Non-invasive mechanical ventilation (NIV) use in patients admitted with acute respiratory failure due to COPD exacerbations (AECOPDs) varies significantly between hospitals. However, previous literature did not account for patients’ illness severity. Our objective was to examine the variation in risk-standardized NIV use after adjusting for illness severity.

Methods

We retrospectively analyzed AECOPD hospitalizations from 2011 to 2017 at 106 acute-care Veterans Health Administration (VA) hospitals in the USA. We stratified hospitals based on the percentage of NIV use among patients who received ventilation support within the first 24 hours of admission into quartiles, and compared patient characteristics. We calculated the risk-standardized NIV % using hierarchical models adjusting for comorbidities and severity of illness. We then stratified the hospitals by risk-standardized NIV % into quartiles and compared hospital characteristics between quartiles. We also compared the risk-standardized NIV % between rural and urban hospitals.

Results

In 42,048 admissions for AECOPD over 6 years, the median risk-standardized initial NIV % was 57.3% (interquartile interval [IQI]=41.9–64.4%). Hospitals in the highest risk-standardized NIV % quartiles cared for more rural patients, used invasive ventilators less frequently, and had longer length of hospital stay, but had no difference in mortality relative to the hospitals in the lowest quartiles. The risk-standardized NIV % was 65.3% (IQI=34.2–84.2%) in rural and 55.1% (IQI=10.8–86.6%) in urban hospitals (p=0.047), but hospital mortality did not differ between the two groups.

Conclusion

NIV use varied significantly across hospitals, with rural hospitals having higher risk-standardized NIV % rates than urban hospitals. Further research should investigate the exact mechanism of variation in NIV use between rural and urban hospitals.

Helmet non-invasive ventilation compared to facemask non-invasive ventilation and high flow nasal cannula in acute respiratory failure: a systematic review and meta-analysis

BACKGROUND

Although small randomised controlled trials (RCTs) and observational studies have examined helmet non-invasive ventilation (NIV), uncertainty remains regarding its role. We conducted a systematic review and meta-analysis to examine the effect of helmet NIV compared to facemask NIV or high flow nasal cannula (HFNC) in acute respiratory failure.

METHODS

We searched multiple databases to identify RCTs and observational studies reporting on at least one of mortality, intubation, ICU length of stay, NIV duration, complications, or comfort with NIV therapy. We assessed study risk of bias (ROB) using the Cochrane ROB tool for RCTs and the Ottawa-Newcastle scale for observational studies and rated certainty of pooled evidence using GRADE.

RESULTS

We separately pooled data from 16 RCTs (n=949) and 8 observational studies (n=396). Compared to facemask NIV, based on low certainty evidence, helmet NIV may reduce mortality (relative risk (RR) 0.56, 95% confidence interval (CI) (0.33 to 0.95)), and intubation (RR 0.35, 95% CI (0.22 to 0.56)) in both hypoxic and hypercapnic respiratory failure but may have no effect on duration of NIV. There was an uncertain effect of helmet on ICU length of stay and development of pressure sores. Data from observational studies was consistent with the foregoing findings but of lower certainty. Based on low and very low certainty data, helmet NIV may reduce intubation compared to HFNC, but its effect on mortality is uncertain.

CONCLUSION

Compared to facemask NIV, helmet NIV may reduce mortality and intubation; however, the effect of helmet compared to HFNC remains uncertain.

Survey on accessibility and real-life application of noninvasive ventilation

Noninvasive mechanical ventilation (NIV) is an accepted method of respiratory failure treatment; however, at present, little is known about the global factors limiting NIV application. A survey designed to determine NIV accessibility and limiting factors in world economies and regions was developed. The questionnaire was sent to members of the European Respiratory Society (ERS) Respiratory Intensive Care Assembly and all ERS National Delegates. Replies to the survey were collected from 161 respondents from 46 countries. NIV was found to be provided most frequently by pulmonologists and intensivists. In high-income economies (HIEs), NIV reimbursement in chronic respiratory failure treatment was found to be independent of the underlying disease and supplementary insurance (p<0.0001), whereas in upper-middle-income economies (UMIEs) it was found to be dependent on the underlying disease (p<0.0001). In chronic respiratory failure, NIV was not reimbursed in lower-middle-income economies (LMIEs) (p<0.0001). In LMIEs and UMIEs, the lack of financial resources was the main limiting factor in acute (p=0.007) and chronic respiratory failure (p<0.0001). In the income-level-based assessment, financing was recognised as relevant in LMIEs and UMIEs (p<0.0001), equipment in LMIEs and UMIEs (p=0.03), medical staff in all economies (p=0.02), and legal regulations in LMIEs (p=0.0005). It was confirmed that NIV in acute and chronic respiratory failure is reimbursed based on government regulations in UMIEs and HIEs (p<0.0001), and is not reimbursed and probably will not be reimbursed in the near future in LMIEs (p<0.0001). We conclude that financial constraints are still considered a major limiting factor for NIV use.

Noninvasive ventilation in acute respiratory failure: which recipe for success?

Noninvasive positive-pressure ventilation (NPPV) to treat acute respiratory failure has expanded tremendously over the world in terms of the spectrum of diseases that can be successfully managed, the locations of its application and achievable goals.

The turning point for the successful expansion of NPPV is its ability to achieve the same physiological effects as invasive mechanical ventilation with the avoidance of the life-threatening risks correlated with the use of an artificial airway.

Cardiorespiratory arrest, extreme psychomotor agitation, severe haemodynamic instability, nonhypercapnic coma and multiple organ failure are absolute contraindications for NPPV. Moreover, pitfalls of NPPV reduce its rate of success; consistently, a clear plan of what to do in case of NPPV failure should be considered, especially for patients managed in unprotected setting. NPPV failure is likely to be reduced by the application of integrated therapeutic tools in selected patients handled by expert teams.

In conclusion, NPPV has to be considered as a rational art and not just as an application of science, which requires the ability of clinicians to both choose case-by-case the best “ingredients” for a “successful recipe” (i.e.patient selection, interface, ventilator, interface,etc.) and to avoid a delayed intubation if the ventilation attempt fails.

Successful Use of Noninvasive Ventilation in Chronic Obstructive Pulmonary Disease. How Do High-Performing Hospitals Do It?

RATIONALE

Noninvasive ventilation (NIV) is a cornerstone of treatment for patients with severe exacerbations of chronic obstructive pulmonary disease (COPD), where it has been shown to reduce the need for intubation, hospital length of stay, and mortality. Despite high-quality evidence and strong recommendations in clinical guidelines, use of NIV varies widely across hospitals.

OBJECTIVES

To identify approaches used by hospitals that have been successful in implementing NIV to treat patients with severe exacerbations of COPD.

METHODS

Adopting a positive deviance approach, in-depth interviews were conducted with key stakeholders from a sample of high-performing hospitals selected from a large and representative network of 386 U.S. hospitals. High performers were defined as hospitals in which a high proportion of patients with COPD requiring mechanical ventilation were treated with NIV, and that also achieved low risk-adjusted mortality for all patients with COPD. Interviews were audio-recorded and transcribed verbatim. Themes and subthemes were identified through iterative readings of the transcripts and discussion until the team agreed that all important themes and subthemes had been identified. All transcripts were coded by three or four researchers. Differences in coding were discussed to negotiate consensus, resulting in a single agreed-on set of coded transcripts.

RESULTS

Interviews were conducted with 32 participants from seven hospitals. Hospitals were diverse regarding size, teaching status, and geographic location. Participants included respiratory therapists (n = 15), physicians (n = 10), and nurses (n = 7). The qualitative analyses revealed three interrelated domains that characterized effective NIV use: processes, structural elements, and contextual factors. Several themes comprised each domain. Key processes included timely identification of appropriate patients, early initiation of NIV, frequent reassessment of patients, and attention to patient comfort. Necessary structural elements included adequate equipment, sufficient numbers of qualified respiratory therapists, and flexibility in staffing. Important contextual factors included provider buy-in, respiratory therapist autonomy, interdisciplinary teamwork, and staff education. Hospital leaders, policies, and protocols were identified as playing a supporting role in promoting essential elements.

CONCLUSIONS

We identified factors, such as respiratory therapist autonomy, that facilitated essential processes (e.g., timely initiation) of NIV use at high-performing hospitals. These findings may be useful to hospitals seeking to optimize their use of NIV among patients with COPD.

Non-invasive ventilation in children and adults in low- and low-middle income countries: A systematic review and meta-analysis

PURPOSE

We systematically reviewed the effects of NIV for acute respiratory failure (ARF) in low- and low-middle income countries.

MATERIALS AND METHODS

We searched MEDLINE, CENTRAL, and EMBASE (to January 2016) for observational studies and trials of NIV for ARF or in the peri-extubation period in adults and post-neonatal children. We abstracted outcomes data and assessed quality. Meta-analyses used random-effect models.

RESULTS

Fifty-four studies (ten pediatric/n=1099; 44 adult/n=2904), mostly South Asian, were included. Common diagnoses were pneumonia and chronic obstructive pulmonary disease (COPD). Considering observational studies and the NIV arm of trials, NIV was associated with moderate risks of mortality (pooled risk 9.5%, 95% confidence interval (CI) 4.6-14.5% in children; 16.2% [11.2-21.2%] in adults); NIV failure (10.5% [4.6-16.5%] in children; 28.5% [22.4-34.6%] in adults); and intubation (5.3% [0.8-9.7%] in children; 28.8% [21.9-35.8%] in adults). The risk of mortality was greater (p=0.035) in adults with hypoxemic (25.7% [15.2-36.1%]) vs. hypercapneic (12.8% [7.0-18.6%]) ARF. NIV reduced mortality in COPD (relative risk [RR] 0.47 [0.27-0.79]) and in patients weaning from ventilation (RR 0.48 [0.28-0.80]). The pooled pneumothorax risk was 2.4% (0.8-3.9%) in children and 5.2% (1.0-9.4%) in adults. Meta-analyses had high heterogeneity.

CONCLUSIONS

NIV for ARF in these settings appears to be effective.

Indications and practical approach to non-invasive ventilation in acute heart failure

In acute heart failure (AHF) syndromes significant respiratory failure (RF) is essentially seen in patients with acute cardiogenic pulmonary oedema (ACPE) or cardiogenic shock (CS). Non-invasive ventilation (NIV), the application of positive intrathoracic pressure through an interface, has shown to be useful in the treatment of moderate to severe RF in several scenarios. There are two main modalities of NIV: continuous positive airway pressure (CPAP) and pressure support ventilation (NIPSV) with positive end expiratory pressure. Appropriate equipment and experience is needed for NIPSV, whereas CPAP may be administered without a ventilator, not requiring special training. Both modalities have shown to be effective in ACPE, by a reduction of respiratory distress and the endotracheal intubation rate compared to conventional oxygen therapy, but the impact on mortality is less conclusive. Non-invasive ventilation is also indicated in patients with AHF associated to pulmonary disease and may be considered, after haemodynamic stabilization, in some patients with CS. There are no differences in the outcomes in the studies comparing both techniques, but CPAP is a simpler technique that may be preferred in low-equipped areas like the pre-hospital setting, while NIPSV may be preferable in patients with significant hypercapnia. The new modality 'high-flow nasal cannula' seems promising in cases of AHF with less severe RF. The correct selection of patients and interfaces, early application of the technique, the achievement of a good synchrony between patients and the ventilator avoiding excessive leakage, close monitoring, proactive management, and in some cases mild sedation, may warrant the success of the technique.

Epidemiology of NIV for Acute Respiratory Failure in COPD Patients: Results from the International Surveys vs. the "Real World"

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.

Noninvasive ventilation for acute exacerbations of asthma: A systematic review of the literature

BACKGROUND

Asthma is a chronic disease characterised by reversible airway obstruction caused by bronchospasm, mucous and oedema. People with asthma commonly experience acute exacerbations of their disease requiring hospitalisation and subsequent utilisation of economic and healthcare resources. Noninvasive ventilation has been suggested as a treatment for acute exacerbations of asthma due to its ability to provide airway stenting, optimal oxygen delivery and decreased work of breathing.

OBJECTIVES

This paper is a systematic review of the available published research focused on the use of noninvasive ventilation for the treatment of acute exacerbations of asthma to determine if this treatment provides better outcomes for patients compared to standard medical therapy.

METHOD

Database searches were conducted using EBSCOhost, MEDLINE and PubMed. Search terms used were combinations of 'noninvasive ventilation', 'BiPAP', 'CPAP', 'wheez*' and 'asthma'. Articles were included if they were research papers focused on adult patients with asthma and a treatment of noninvasive ventilation, and were published in full text in English. Included articles were reviewed using the National Health and Medical Research Council (Australia) evidence hierarchy and quality appraisal tools.

RESULTS

There were 492 articles identified from the database searches. After application of inclusion/exclusion criteria 13 articles were included in the systematic review. Studies varied significantly in design, endpoints and outcomes. There was a trend in better outcomes for patients with acute asthma who were treated with noninvasive ventilation compared to standard medical therapy, however, the variability of the studies meant that no conclusive recommendations could be made.

CONCLUSION

More research is required before noninvasive ventilation can be conclusively recommended for the treatment of acute exacerbations of asthma.

Can patients with moderate to severe acute respiratory failure from COPD be treated safely with noninvasive mechanical ventilation on the ward?

Purpose

Noninvasive mechanical ventilation (NIMV) usage outside of intensive care unit is not recommended in patients with COPD for severe acute respiratory failure (ARF). We assessed the factors associated with failure of NIMV in patients with ARF and severe acidosis admitted to the emergency department and followed on respiratory ward.

Patients and methods

This is a retrospective observational cohort study conducted in a tertiary teaching hospital specialized in chest diseases and thoracic surgery between June 1, 2013 and May 31, 2014. COPD patients who were admitted to our emergency department due to ARF were included. Patients were grouped according to the severity of acidosis into two groups: group 1 (pH=7.20–7.25) and group 2 (pH=7.26–7.30).

Results

Group 1 included 59 patients (mean age: 70±10 years, 30.5% female) and group 2 included 171 patients (mean age: 67±11 years, 28.7% female). On multivariable analysis, partial arterial oxygen pressure to the inspired fractionated oxygen (PaO₂/FiO₂) ratio <200, delta pH value <0.30, and pH value <7.31 on control arterial blood gas after NIMV in the emergency room and peak C-reactive protein were found to be the risk factors for NIMV failure in COPD patients with ARF in the ward.

Conclusion

NIMV is effective not only in mild respiratory failure but also with severe forms of COPD patients presenting with severe exacerbation. The determination of the failure criteria of NIMV and the expertise of the team is critical for treatment success.

Noninvasive ventilation practice patterns for acute respiratory failure in Canadian tertiary care centres: A descriptive analysis

BACKGROUND

The extent of noninvasive ventilation (NIV) use for patients with acute respiratory failure in Canadian hospitals, indications for use and associated outcomes are unknown.

OBJECTIVE

To describe NIV practice variation in the acute setting.

METHODS

A prospective observational study involving 11 Canadian tertiary care centres was performed. Data regarding NIV indication, mode and outcomes were collected for all adults (>16 years of age) treated with NIV for acute respiratory failure during a four-week period (between February and August 2011). Logistic regression with site as a random effect was used to examine the association between preselected predictors and mortality or intubation.

RESULTS

A total of 330 patients (mean [± SD] 30±12 per centre) were included. The most common indications for NIV initiation were pulmonary edema (104 [31.5%]) and chronic obstructive pulmonary disease (99 [30.0%]). Significant differences in indications for NIV use across sites, specialty of ordering physician and location of NIV initiation were noted. Although intubation rates were not statistically different among sites (range 10.3% to 45.4%), mortality varied significantly (range 6.7% to 54.5%; P=0.006). In multivariate analysis, the most significant independent predictor of avoiding intubation was do-not-resuscitate status (OR 0.11 [95% CI 0.03 to 0.37]).

CONCLUSION

Significant variability existed in NIV use and associated outcomes among Canadian tertiary care centres. Assignment of do-not-resuscitate status prevented intubation.

Opening of a respiratory intermediate care unit in a general hospital: impact on mortality and other outcomes

BACKGROUND

Respiratory intermediate care units (RICUs) are specialized areas aimed at optimizing the cost-benefit ratio of care. No data exist about the impact of opening a RICU on hospital outcomes.

OBJECTIVES

We wondered if opening a RICU may improve the outcomes of patients with acute respiratory failure (ARF), acute exacerbation of chronic obstructive pulmonary disease (AECOPD), or community-acquired pneumonia (CAP).

METHODS

We analyzed the discharge abstracts of 2,372 admissions to the RICU and internal medicine units (IMUs) for ARF, AECOPD, and CAP. The IMUs at the Hospital of Trieste comprise emergency and internal wards. In order to investigate the determinants of outcomes, a matched case-control study was performed using clinical records.

RESULTS

The in-hospital mortality rate was lower in the RICU vs. IMUs (5.4 vs. 19.1%, p = 0.0001). Statistical differences did not change when comparing the RICU with the emergency and internal wards. After adjusting for potential confounders, the risk of death for patients with CAP, AECOPD, or ARF was significantly higher in the IMUs than in the RICU (OR 6.90, 3.19, and 6.7, respectively, p < 0.04). Both the frequency of transfer to the ICU (6 vs. 12%, p = 0.0001, OR 0.38) and the hospital stay (9.3 vs. 12.1 days, p = 0.0001) were reduced in patients admitted to the RICU compared to those admitted to non-RICUs. Significant differences were found in care management concerning chest physiotherapy, mechanical ventilation, antibiotics, and corticosteroids.

CONCLUSIONS

The opening of a RICU may be advantageous to reduce in-hospital mortality, the need for ICU admission, and the hospital stay of patients with AECOPD, CAP, and ARF. Better use of care resources contributed to better patient management in the RICU.

[Noninvasive ventilation for acute respiratory failure in a pulmonary department]

INTRODUCTION

Noninvasive ventilation (NIV) is considered as the first choice treatment for selected patients with acute respiratory failure (ARF), but many hospitals are forced to start NIV on medical wards.

METHODS

The aim of this retrospective study was to assess the outcomes of NIV initiated for ARF on a respiratory ward and to find the criteria predictive of failure. All patients were treated in a four-bed ward specifically dedicated to NIV. Failure of NIV was defined as the need for intubation and transfer to ICU, or death.

RESULTS

Among 105 admissions with ARF, 49 episodes needed NIV. These episodes were divided into 2 groups: PaCO2<45mmHg (10) and PaCO2>45mmHg (39). The overall failure rate of NIV and overall in-hospital mortality rate were 26.5% and 17% respectively. On multivariate analysis, SAPS II and respiratory acidosis with a pH less than 7.30 were significantly associated with failure of NIV.

CONCLUSIONS

NIV is practicable and is effective in the management of mild to moderate ARF on a respiratory ward. However, patients with respiratory acidosis and a pH less than 7.30 are at risk of NIV failure.

[Intensive care unit profesionals's knowledge about non invasive ventilation comparative analysis]

AIMS

The literature highlights the lack of noninvasive ventilation (NIV) protocols and the variability of the knowledge of NIV between intensive care units (ICU) and hospitals, so we want to compare NIV nurses's Knowledge from 4 multipurpose ICU and one surgical ICU.

METHODS

Multicenter, crosscutting, descriptive study in three university hospitals. The survey instrument was validated in a pilot test, and the calculated Kappa index was 0.9. Returning a completed survey is an indication of informed consent. Analysis by Chi square test.

RESULTS

117 responded (65%) nurses, 11±9.7 years of experience in ICU and 9.2±7.2 in use of NIV. One of the multipurpose ICU, was initiated NIV an average of 6 years later than the others (95% CI [3.3 to 8.6], P<.001). Only 23.1% of nurses would place a non-vented mask (with no exhalation port) by conventional ventilator, the rest any kind of face mask. 12.7% believed that the mask must be adjusted to the "2-finger" fit while 29% would seal the mask to the patient's face and cover the mask opening where air escapes to facilitate patient/ventilator synchronization. In the surgical ICU agitation identifies mostly as a complication of NIV compared with multipurpose UCIs (31.6% vs 1.8%, P<.001). 56.4% of nurses do not consider respiratory physiotherapy as nursing care, with no difference between units.

CONCLUSIONS

Knowledge about types of interface is very dependent on the material of the unit. More training for complications of NIV as agitation and handling secretions it is necessary.

Outcomes associated with invasive and noninvasive ventilation among patients hospitalized with exacerbations of chronic obstructive pulmonary disease

IMPORTANCE

Small clinical trials have shown that noninvasive ventilation (NIV) is efficacious in reducing the need for intubation and improving short-term survival among patients with severe exacerbations of chronic obstructive pulmonary disease (COPD). Little is known, however, about the effectiveness of NIV in routine clinical practice.

OBJECTIVE

To compare the outcomes of patients with COPD treated with NIV to those treated with invasive mechanical ventilation (IMV).

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective cohort study of 25 628 patients hospitalized for exacerbation of COPD who received mechanical ventilation on the first or second hospital day at 420 US hospitals participating in the Premier Inpatient Database.

EXPOSURES

Initial ventilation strategy.

MAIN OUTCOMES AND MEASURES

In-hospital mortality, hospital-acquired pneumonia, hospital length of stay and cost, and 30-day readmission.

RESULTS

In the study population, a total of 17 978 (70%) were initially treated with NIV on hospital day 1 or 2. When compared with those initially treated with IMV, NIV-treated patients were older, had less comorbidity, and were less likely to have concomitant pneumonia present on admission. In a propensity-adjusted analysis, NIV was associated with lower risk of mortality than IMV (odds ratio [OR] 0.54; [95% CI, 0.48-0.61]). Treatment with NIV was associated with lower risk of hospital-acquired pneumonia (OR, 0.53 [95% CI, 0.44-0.64]), lower costs (ratio, 0.68 [95% CI, 0.67-0.69]), and a shorter length of stay (ratio, 0.81 [95% CI, 0.79-0.82]), but no difference in 30-day all-cause readmission (OR, 1.04 [95% CI, 0.94-1.15]) or COPD-specific readmission (OR, 1.05 [95% CI, 0.91-1.22]). Propensity matching attenuated these associations. The benefits of NIV were similar in a sample restricted to patients younger than 85 years and were attenuated among patients with higher levels of comorbidity and concomitant pneumonia. Using the hospital as an instrumental variable, the strength of association between NIV and mortality was modestly attenuated (OR, 0.66 [95% CI, 0.47-0.91]). In sensitivity analyses, the benefit of NIV was robust in the face of a strong hypothetical unmeasured confounder.

CONCLUSIONS AND RELEVANCE

In a large retrospective cohort study, patients with COPD treated with NIV at the time of hospitalization had lower inpatient mortality, shorter length of stay, and lower costs compared with those treated with IMV.

Use and outcomes of noninvasive positive pressure ventilation in acute care hospitals in Massachusetts

BACKGROUND

This study determined actual utilization rates and outcomes of noninvasive positive pressure ventilation (NIV) at selected hospitals that had participated in a prior survey on NIV use.

METHODS

This observational cohort study, based at eight acute care hospitals in Massachusetts, focused on all adult patients requiring ventilatory support for acute respiratory failure during predetermined time intervals.

RESULTS

Of 548 ventilator starts, 337 (61.5%) were for invasive mechanical ventilation and 211 (38.5%) were for NIV, with an overall NIV success rate of 73.9% (ie, avoidance of intubation or death while on NIV or within 48 h of discontinuation). Causal diagnoses for respiratory failure were classified as (I) acute-on-chronic lung disease (23.5%), (II) acute de novo respiratory failure (17.9%), (III) neurologic disorders (19%), (IV) cardiogenic pulmonary edema (16.8%), (V) cardiopulmonary arrest (12.2%), and (VI) others (10.6%). NIV use and success rates for each of the causal diagnoses were, respectively, (I) 76.7% and 75.8%, (II) 37.8% and 62.2%, (III) 1.9% and 100%, (IV) 68.5% and 79.4%, (V) none, and (VI) 17.2% and 60%. Hospital mortality rate was higher in patients with invasive mechanical ventilation than in patients with NIV (30.3% vs 16.6%, P &lt; .001).

CONCLUSIONS

NIV occupies an important role in the management of acute respiratory failure in acute care hospitals in selected US hospitals and is being used for a large majority of patients with acute-on-chronic respiratory failure and acute cardiogenic pulmonary edema. NIV use appears to have increased substantially in selected US hospitals over the past decade.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00458926; URL: www.clinicaltrials.gov.

New modalities for non-invasive ventilation

There is now substantial evidence supporting the use of non-invasive ventilation in acute hypercpanic exacerbations of chronic respiratory failure, and early trials show nocturnal ventilatory support may benefit chronic heart failure patients with sleep disordered breathing. Attention is now being focused on innovative modes which adapt respiratory support to the user's ventilatory pattern, eg adaptive service ventilation and assured volume delivery 'intelligent' ventilation.

Noninvasive mechanical ventilation: An 18-month experience of two tertiary care hospitals in north India

BACKGROUND

Noninvasive mechanical ventilation (NIMV) is the delivery of positive pressure ventilation through an interface to upper airways without using the invasive airway. Use of NIMV is becoming common with the increasing recognition of its benefits.

OBJECTIVES

This study was done to evaluate the feasibility and outcome of NIMV in tertiary care centres.

MATERIALS AND METHODS

An observational, retrospective study conducted over a period of 18 months in two tertiary level hospitals of north India on 184 consecutive patients who were treated by NIMV, regardless of the indication. NIMV was given in accordance with the arterial blood gas (ABG) parameters defining respiratory failure (Type 1/Type 2).

RESULTS

The most common indication of NIMV in our hospitals was acute exacerbation of chronic obstructive pulmonary disease (AE-COPD 80.43%), and 90.54% AE-COPD patients were improved by NIMV. Application of NIMV resulted in significant improvement of pH and blood gases in COPD patients, while non-COPD patients showed significant improvement in partial pressure of oxygen (PaO2) alone. The mean duration of NIMV was 8.35 ± 5.98 days, and patients of interstitial lung disease (ILD) were on NIMV for the maximum duration (17 ± 8.48 days). None of the patients of acute respiratory distress syndrome were cured by NIMV; 13.04% patients on NIMV required intubation and mechanical ventilation.

CONCLUSION

This study demonstrates and encourages the use of NIMV as the first-line ventilatory treatment in AE-COPD patients with respiratory failure. It also supports NIMV usage in other causes of respiratory failure as a promising step toward prevention of mechanical ventilation.

A comparison of bilevel and continuous positive airway pressure noninvasive ventilation in acute cardiogenic pulmonary edema

BACKGROUND

Whether bilevel positive airway pressure (BiPAP) is advantageous compared with continuous positive airway pressure (CPAP) in acute cardiogenic pulmonary edema (ACPO) remains uncertain. The aim of the meta-analysis was to assess potential beneficial and adverse effects of CPAP compared with BiPAP in patients with ACPO.

METHODS

Randomized controlled trials comparing the treatment effects of BiPAP with CPAP were identified from electronic databases and reference lists from January 1966 to December 2012. Two reviewers independently assessed study quality. In trials that fulfilled inclusion criteria, we critically evaluate the evidence for the use of noninvasive ventilation on rates of hospital mortality, endotracheal intubation, myocardial infarction, and the length of hospital stay. Data were combined using Review Manager 4.3 (The Cochrane Collaboration, Oxford, UK). Both pooled effects and 95% confidence intervals (CIs) were calculated.

RESULTS

Twelve randomized controlled trials with a total of 1433 patients with ACPO were included. The hospital mortality (relative risk [RR], 0.86; 95% CI, 0.65-1.14; P = .46; I(2) = 0%) and need for requiring invasive ventilation (RR, 0.89; 95% CI, 0.57-1.38; P = .64; I(2) = 0%) were not significantly different between patients treated with CPAP and those treated with BiPAP. The occurrence of new cases of myocardial infarction (RR, 0.95; 95% CI, 0.77-1.17; P = .53, I(2) = 0%) and length of hospital stay (RR, 1.01; 95% CI, -0.40 to 2.41; P = .98; I(2) = 0%) were also not significantly different between the 2 groups.

CONCLUSIONS

There are no significant differences in clinical outcomes when comparing CPAP vs BiPAP. Based on the limited data available, our results suggest that there are no significant differences in clinical outcomes when comparing CPAP with BiPAP.

Comparative effectiveness of noninvasive ventilation vs invasive mechanical ventilation in chronic obstructive pulmonary disease patients with acute respiratory failure

BACKGROUND

Limited evidence exists on the comparative effectiveness of noninvasive ventilation (NIV) vs invasive mechanical ventilation (IMV) in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients with respiratory failure.

OBJECTIVES

To characterize the use of NIV and IMV, and to compare the effectiveness of NIV vs IMV in AECOPD.

DESIGN AND PATIENTS

Retrospective cohort study using data from the 2006-2008 Nationwide Emergency Department Sample. Emergency department visits for AECOPD with acute respiratory failure were identified with codes from the International Classification of Diseases, Ninth Revision, Clinical Modification.

MEASURES

The outcome measures were inpatient mortality, hospital length of stay, hospital charges, and complications.

RESULTS

There were an estimated 101,000 visits annually for AECOPD with acute respiratory failure; 96% were admitted to the hospital. Of these, NIV use increased from 14% in 2006 to 16% in 2008 (P=0.049). Use of NIV, however, varied widely between hospitals, ranging from 0% to 100% with a median of 11%. Noninvasive ventilation was more often used in higher-case volume, Northeastern hospitals. In a propensity score analysis, NIV use, compared with IMV, was associated with lower inpatient mortality (risk ratio: 0.54, 95% confidence interval [CI]: 0.50-0.59), shortened hospital length of stay (-3.2 days; 95% CI: -3.4 to -2.9 days), lower hospital charges (-$35,012; 95% CI: -$36,848 to -$33,176), and lower risk of iatrogenic pneumothorax (0.05% vs 0.5%, P<0.001).

CONCLUSIONS

Although NIV use is increasing in US hospitals, its adoption remains low and varies widely between hospitals. Our observational study suggests NIV appears to be more effective and safer than IMV for AECOPD in the real-world setting.

Use of noninvasive ventilation in patients with acute respiratory failure, 2000-2009: a population-based study

RATIONALE

Although evidence supporting use of noninvasive ventilation (NIV) during acute exacerbations of chronic obstructive pulmonary disease (COPD) is strong, evidence varies widely for other causes of acute respiratory failure.

OBJECTIVES

To compare utilization trends and outcomes associated with NIV in patients with and without COPD.

METHODS

We identified 11,659,668 cases of acute respiratory failure from the Nationwide Inpatient Sample during years 2000 to 2009 and compared NIV utilization trends and failure rates for cases with or without a diagnosis of COPD.

MEASUREMENTS AND MAIN RESULTS

The proportion of patients with COPD who received NIV increased from 3.5% in 2000 to 12.3% in 2009 (250% increase), and the proportion of patients without COPD who received NIV increased from 1.2% in 2000 to 6.0% in 2009 (400% increase). The rate of increase in the use of NIV was significantly greater for patients without COPD (18.1% annual change) than for patients with COPD (14.3% annual change; P = 0.02). Patients without COPD were more likely to have failure of NIV requiring endotracheal intubation (adjusted odds ratio, 1.19; 95% confidence interval, 1.15-1.22; P < 0.0001). Patients in whom NIV failed had higher hospital mortality than patients receiving mechanical ventilation without a preceding trial of NIV (adjusted odds ratio, 1.14; 95% confidence interval, 1.11-1.17; P < 0.0001).

CONCLUSION

The use of NIV during acute respiratory failure has increased at a similar rate for all diagnoses, regardless of supporting evidence. However, NIV is more likely to fail in patients without COPD, and NIV failure is associated with increased mortality.

Noninvasive ventilation initiation in clinical practice: A six-year prospective, observational study

BACKGROUND

Despite evidence supporting the role of noninvasive ventilation (NIV) in diverse populations, few publications describe how NIV is used in clinical practice.

OBJECTIVE

To describe NIV initiation in a teaching hospital that has a guideline, and to characterize temporal changes in NIV initiation over time.

METHODS

A prospective, observational study of continuous positive airway pressure ventilation (CPAP) or bilevel NIV initiation from January 2000 to December 2005 was conducted. Registered respiratory therapists completed a one-page data collection form at NIV initiation.

RESULTS

Over a six-year period, NIV was initiated in 623 unique patients (531 bilevel NIV, 92 CPAP). Compared with bilevel NIV, CPAP was initiated more often using a nasal interface, with a machine owned by the patient, and for chronic conditions, especially obstructive sleep apnea. Whereas CPAP was frequently initiated and continued on the wards, bilevel NIV was most frequently initiated and continued in the emergency department, intensive care unit and the coronary care unit. Patients initiated on bilevel NIV were more likely to be female (OR 1.8, 95% CI 1.08 to 2.85; P=0.02) and to have an acute indication compared with CPAP initiations (OR 7.5, 95% CI 1.61 to 34.41; P=0.01). Bilevel NIV was initiated more often in the emergency department than in the intensive care unit (OR 5.8, 95% CI 0.89 to 38.17; P=0.07). Bilevel NIV initiation increased from 2000 to 2005.

CONCLUSIONS

The present study illustrates how NIV is used in clinical practice and confirms that NIV initiation has increased over time.

Noninvasive ventilation in adults with acute respiratory distress: a primer for the clinician

Noninvasive ventilation (NIV) has become an integral part of critical care management. Despite > 2 decades of experience, it is relatively underused, with general utilization reported as a little over 10% in a recent international survey. Lack of training, knowledge, equipment, and experience with NIV may account for its slow adoption. Patient selection, staff training and experience, and prompt recognition of ineffective NIV are important components to successful application of NIV. Noninvasive ventilation does have a learning curve that may be steep for some institutions but must be mastered if the procedure is to become a successful institutional component of care. Patients with acute respiratory failure due to chronic obstructive pulmonary disease or congestive heart failure are ideal candidates for NIV, and optimal efficacy in associated conditions is often linked to these 2 conditions. Technical issues and written guidelines are addressed, including details of an adequate trial of therapy as well as criteria for intubation. Attention to these elements should increase the success rate of NIV, which in turn should increase its general use.

Noninvasive ventilation: a survey of practice patterns of its use in India

Background and Aims:

To understand the practice patterns of noninvasive ventilation (NIV) use by Indian physicians.

Subjects and Methods:

Around three thousand physicians from all over India were mailed a questionnaire that could capture the practice patterns of NIV use.

Results:

Completed responses were received from 648 physicians (21.6%). Majority (n = 469, 72.4%, age 40 ± 9 years, M:F 409:60) use NIV in their clinical practice. NIV was most exclusively being used in the ICU setting (68.4%) and the commonest indication for its use was chronic obstructive pulmonary disease (COPD) (71.4%). A significant number did not report use of a conventional ventilator for NIV support (62%). Oronasal mask was the overwhelming favorite among the sampled physicians (68.2%). In most of the cases, the treating physician initiated NIV (60.8%) and a baseline blood gas analysis was performed in only 71.1% of the cases (315/443). Nasal bridge pressure sores was the commonest complication (64.2%).

Conclusions:

NIV is being widely used in clinical practice in India for various indications. COPD is the most common indication for its deployment. There seems to be a marked variability in the patterns relating to actual deployment of NIV, including the site of initiation, protocols for initiation followed, and monitoring of patients.

The use of non-invasive ventilation for life-threatening asthma attacks: Changes in the need for intubation

BACKGROUND AND OBJECTIVE

Although non-invasive ventilation (NIV) has been shown to be effective in a wide variety of respiratory diseases, its role in severe asthma attacks remains uncertain. The aim of this study was to clarify the effectiveness of NIV in patients experiencing severe attacks of asthma.

METHODS

A retrospective cohort study was performed, comparing the periods November 1999-October 2003 (pre-introduction of NIV) and November 2004-October 2008 (post-introduction of NIV). The data and clinical outcomes for patients who experienced severe attacks of asthma, and who fulfilled the inclusion criteria, were retrieved and compared.

RESULTS

Fifty events (48 patients) from the pre-NIV period and 57 events (54 patients) from the post-NIV period, which required hospitalization, were included in the analysis. Nine of the 50 pre-NIV events (mean PaO(2)/fraction of inspired O(2) (FiO(2)) 241 +/- 161; PaCO(2) 79 +/- 40) were treated primarily by endotracheal intubation (ETI), while 17 of the 57 post-NIV events (PaO(2)/FiO(2) 197 +/- 132, P = 0.39; PaCO(2) 77 +/- 30, P = 0.95) were treated primarily by NIV. The rate of ETI decreased in the post-NIV period (2/57 (3.5%) vs 9/50 (18%), P = 0.01). NIV was started earlier than mechanical ventilation (MV) with ETI (mean time interval between arrival and start of MV 171.7 +/- 217.9 min vs 38.5 +/- 113.8 min for NIV, P < 0.05). In the post-NIV cohort, there was a trend towards a reduction in the duration of MV with ETI or NIV (36.9 +/- 38.4 h vs 20.3 +/- 35.8 h, P = 0.09), and hospital stay was shortened (12.6 +/- 4.2 vs 8.4 +/- 2.8 days, P < 0.01). No deaths occurred during this period as a consequence of asthma attacks.

CONCLUSIONS

The need for ETI in patients with severe attacks of asthma was decreased after introduction of NIV. The ready availability of NIV enabled the rapid commencement of MV and may decrease the need for ETI. NIV is an acceptable and useful method of stabilizing patients experiencing severe attacks of asthma.

Patient outcomes after noninvasive mechanical ventilation at a high dependency unit of an emergency department

OBJECTIVE

To describe the outcome of patients after noninvasive ventilation in a high dependency unit (HDU) of an emergency department (ED). Secondary aims were to define the role of intensive care consultation and to identify variables associated with mortality.

METHODS

Observational, prospective 6-month study.

RESULTS

Two hundred and nine cases were analysed. Thirty-four patients were initially rejected by the intensive care unit (ICU). Physicians in the ED did not request ICU consultation in the remaining 175 (83%) because of 'belief of improvable medical condition in the ED in patients without therapeutic limits' in 93 (group 1) and to 'preset therapeutic limits' or 'comfort measures only' in 82 (groups 2 and 3). Ten out of these 175 were subsequently admitted to the ICU. The global in-hospital mortality rate was 22% (3.3% in the high dependency unit), but only 10% in group 1. Place of referral for ventilation (P<0.001), absence of subsequent ventilation on the general ward (P<0.001), group of assignation (P=0.004), intensive care initial rejection (P=0.022), no previous home ventilation (P=0.028), older age (P=0.03) and longer duration on ventilation (P=0.047) were significantly associated with mortality. In the multivariate regression model, ventilating patients from general wards (odds ratio=7.1; 2.3-25, 95% confidence interval) and ventilation under preset limits (odds ratio=3.57; 1.42-8.98, 95% confidence interval) remained significantly associated with mortality.

CONCLUSION

Noninvasive ventilation is a relatively safe and effective treatment in the ED when performed in carefully controlled settings. ICU consultation may be securely deferred in this setting.

Epidemiology of mechanical ventilation: analysis of the SAPS 3 database

OBJECTIVE

To evaluate current practice of mechanical ventilation in the ICU and the characteristics and outcomes of patients receiving it.

DESIGN

Pre-planned sub-study of a multicenter, multinational cohort study (SAPS 3).

PATIENTS

13,322 patients admitted to 299 intensive care units (ICUs) from 35 countries.

INTERVENTIONS

None.

MAIN MEASUREMENTS AND RESULTS

Patients were divided into three groups: no mechanical ventilation (MV), noninvasive MV (NIV), and invasive MV. More than half of the patients (53% [CI: 52.2-53.9%]) were mechanically ventilated at ICU admission. FIO2, VT and PEEP used during invasive MV were on average 50% (40-80%), 8 mL/kg actual body weight (6.9-9.4 mL/kg) and 5 cmH2O (3-6 cmH2O), respectively. Several invMV patients (17.3% (CI:16.4-18.3%)) were ventilated with zero PEEP (ZEEP). These patients exhibited a significantly increased risk-adjusted hospital mortality, compared with patients ventilated with higher PEEP (O/E ratio 1.12 [1.05-1.18]). NIV was used in 4.2% (CI: 3.8-4.5%) of all patients and was associated with an improved risk-adjusted outcome (OR 0.79, [0.69-0.90]).

CONCLUSION

Ventilation mode and parameter settings for MV varied significantly across ICUs. Our results provide evidence that some ventilatory modes and settings could still be used against current evidence and recommendations. This includes ventilation with tidal volumes >8mL/kg body weight in patients with a low PaO2/FiO2 ratio and ZEEP in invMV patients. Invasive mechanical ventilation with ZEEP was associated with a worse outcome, even after controlling for severity of disease. Since our study did not document indications for MV, the association between MV settings and outcome must be viewed with caution.

Assessing the sensibility of two clinical decision support systems

Clinicians in Emergency Medicine (EM) are increasingly exposed to guidelines and treatment recommendations. To help access and recall these recommendations, electronic Clinical Decision Support Systems (CDSS) have been developed. This study examined the use and sensibility of two CDSS designed for emergency physicians. CDDS for community acquired pneumonia (CAP) and neutropenic fever (NF) were developed by multidisciplinary teams and have been accessed via an intranet-based homepage (eCPG) for several years. Sensibility is a term coined by Feinstein that describes common sense aspects of a survey instrument. It was modified by emergency researchers to include four main headings: (1) Appropriateness; (2) Objectivity; (3) Content; and (4) Discriminative Power. Sensibility surveys were developed using an iterative approach for both the CAP and NF CDSS and distributed to all 25 emergency physicians at one Canadian site. The overall response rate was 88%. Respondents were 88% male and 83% were less than 40; all were attending EM physicians with specialty designations. A number reported never having used the CAP (21%) or NF (33%) CDSS; 54% (CAP) and 21% (NF) of respondents had used the respective CDSS less than 10 times. Overall, both CDSS were rated highly by users with a mean response of 4.95 (SD 0.56) for CAP and 5.62 (SD 0.62) for NF on a seven-point Likert scale. The majority or respondents (CAP 59%, NF 80%) felt that the NF CDSS was more likely than the CAP CDSS to decrease the chances of making a medical error in medication dose, antibiotic choice or patient disposition (4.61 vs. 5.81, p=0.008). Despite being in place for several years, CDSS for CAP and NF are not used by all EM clinicians. Users were generally satisfied with the CDSS and felt that the NF was more likely than the CAP CDSS to decrease medical errors. Additional research is required to determine the barriers to CDSS use.

Health technology assessment in critical care

BACKGROUND

Heath technology assessments (HTAs) evaluate the benefits and costs of devices for monitoring and therapy (and their associated requirements for human resources) which contribute to the high expense associated with ICU admission.

DISCUSSION

Given the limited resources available for health care and increasing demands, funds spent inefficiently or unnecessarily on technologies in the ICU may threaten the sustainability of the health care system or prevent other potentially cost-effective devices from being introduced into clinical care. We discuss the factors impeding the conducting of HTAs in the ICU and suggest strategies for change.

CONCLUSIONS

Despite the need for HTAs of ICU devices only few have been conducted. They should be undertaken more frequently, and their results used to influence clinical practice and hospital and regional-level policy decisions.

Noninvasive ventilation in patients with hypoxemic acute respiratory failure

PURPOSE OF REVIEW

To discuss the recent literature concerning the use of noninvasive ventilation for hypoxemic acute respiratory failure.

RECENT FINDINGS

The benefits of noninvasive ventilation for patients with hypoxemic acute respiratory failure are unclear. In immunocompromised patients and following thoracic surgery, there is a strong rationale for using noninvasive ventilation to treat acute respiratory failure. Prophylactic continuous positive airway pressure after abdominal or thoracic surgery and prophylactic noninvasive ventilation in patients at risk of extubation failure have proved beneficial. Recent studies show that noninvasive ventilation has a favourable impact in immunocompetent patients with acute lung injury/acute respiratory distress syndrome, but caution is required. In hypoxemic acute respiratory failure after extubation, one study reported excess mortality in patients treated with noninvasive ventilation, possibly related to the delay for intubation. A major issue is avoiding undue noninvasive ventilation prolongation and staying alert for predictors of early noninvasive ventilation failure. Caution, close monitoring, and broad experience are required.

SUMMARY

Hypoxemic acute respiratory failure may benefit from noninvasive ventilation or continuous positive airway pressure, but undue prolongation should be avoided. In postextubation respiratory failure there is no evidence for routine use of noninvasive ventilation.

Noninvasive positive pressure ventilation in critical and palliative care settings: understanding the goals of therapy

OBJECTIVE

Although noninvasive positive pressure ventilation (NPPV) is a widely accepted treatment for some patients with acute respiratory failure, the use of NPPV in patients who have decided to forego endotracheal intubation is controversial. Therefore, the Society of Critical Care Medicine charged this Task Force with developing an approach for considering use of NPPV for patients who choose to forego endotracheal intubation.

DATA SOURCES AND METHODS

The Task Force met in person once, by conference call twice, and wrote this document during six subsequent months. We reviewed English-language literature on NPPV for acute respiratory failure. SYNTHESIS AND OVERVIEW: The use of NPPV for patients with acute respiratory failure can be classified into three categories: 1) NPPV as life support with no preset limitations on life-sustaining treatments, 2) NPPV as life support when patients and families have decided to forego endotracheal intubation, and 3) NPPV as a palliative measure when patients and families have chosen to forego all life support, receiving comfort measures only. For each category, we reviewed the rationale and evidence for NPPV, key points to communicate to patients and families, determinants of success and failure, appropriate healthcare settings, and alternative approaches if NPPV fails to achieve the original goals.

CONCLUSIONS

This Task Force suggests an approach to use of NPPV for patients and families who choose to forego endotracheal intubation. NPPV should be applied after careful discussion of the goals of care, with explicit parameters for success and failure, by experienced personnel, and in appropriate healthcare settings. Future studies are needed to evaluate the clinical outcomes of using NPPV for patients who choose to forego endotracheal intubation and to examine the perspectives of patients, families, and clinicians on use of NPPV in these contexts.

Practice guidelines as multipurpose tools: A qualitative study of noninvasive ventilation*

OBJECTIVE

Although practice guidelines for noninvasive ventilation (NIV) for patients with acute respiratory failure (ARF) have the potential to improve processes of care and patient outcomes, clinicians' views about life support technology guidelines are not well understood. The objective was to understand the knowledge about and attitudes toward an NIV guideline for patients with ARF and potential barriers to its use.

DESIGN

Qualitative study based on individual, in-depth, semistructured interviews.

SETTING

St. Joseph's Healthcare, Hamilton, Ontario.

SUBJECTS

Thirty clinicians (six attending physicians, five residents, 12 nurses, and seven respiratory therapists) who used NIV for chronic obstructive pulmonary disease and congestive heart failure patients with ARF, before and after NIV guideline implementation.

INTERVENTIONS

We elicited knowledge and attitudes about, behaviors toward, and barriers to our institutional NIV guideline. We transcribed all interviews and analyzed data in triplicate using grounded theory to identify themes and develop a framework for understanding clinicians' views on guidelines.

MEASUREMENTS AND MAIN RESULTS

The NIV guideline was perceived to define individual clinical responsibilities, improve clinician comfort with use of technology, increase patient safety, and reduce practice variability. Barriers to guideline use included lack of awareness of the guideline, unclear guideline format and presentation, and reluctance about changing practice. Contrary to previous research, participants in this study did not report that the practice guideline limited clinical autonomy. Clinicians used the guideline variously as an educational resource, to access monitored beds, to avoid clinical conflict, or to leverage professional credibility.

CONCLUSIONS

This qualitative study illustrated how the NIV guideline at our institution is understood as a tool that facilitates the multidisciplinary care of patients with ARF. Guideline use may be enhanced through education to improve guideline awareness and increase comfort with recommended practices. Developers should be aware of the role of guidelines for purposes other than bedside decision making for individual patients.

Use of non-invasive ventilation in UK emergency departments

AIM

To describe the current use of non-invasive ventilation in UK emergency departments.

METHODS

A structured questionnaire was sent to all UK emergency departments assessing 25,000 new patients annually.

RESULTS

222 of 233 departments completed the questionnaire. 148 currently use non-invasive ventilation (NIV). Most used NIV for either cardiogenic pulmonary oedema (n = 128) or chronic obstructive pulmonary disease (n = 115). Only 49 departments have protocols for NIV use and 23 audited practice.

CONCLUSION

NIV is commonly used in UK emergency departments. Practices vary significantly. One solution would be the development of guidelines on when and how to use NIV in emergency medicine practice.

Failure of non-invasive ventilation in patients with acute lung injury: observational cohort study

Introduction

The role of non-invasive positive pressure ventilation (NIPPV) in the treatment of acute lung injury (ALI) is controversial. We sought to assess the outcome of ALI that was initially treated with NIPPV and to identify specific risk factors for NIPPV failure.

Methods

In this observational cohort study at the two intensive care units of a tertiary center, we identified consecutive patients with ALI who were initially treated with NIPPV. Data on demographics, APACHE III scores, degree of hypoxemia, ALI risk factors and NIPPV respiratory parameters were recorded. Univariate and multivariate regression analyses were performed to identify risk factors for NIPPV failure.

Results

Of 79 consecutive patients who met the inclusion criteria, 23 were excluded because of a do not resuscitate order and two did not give research authorization. Of the remaining 54 patients, 38 (70.3%) failed NIPPV, among them all 19 patients with shock. In a stepwise logistic regression restricted to patients without shock, metabolic acidosis (odds ratio 1.27, 95% confidence interval (CI) 1.03 to 0.07 per unit of base deficit) and severe hypoxemia (odds ratio 1.03, 95%CI 1.01 to 1.05 per unit decrease in ratio of arterial partial pressure of O₂ and inspired O₂ concentration – PaO₂/FiO₂) predicted NIPPV failure. In patients who failed NIPPV, the observed mortality was higher than APACHE predicted mortality (68% versus 39%, p < 0.01).

Conclusion

NIPPV should be tried very cautiously or not at all in patients with ALI who have shock, metabolic acidosis or profound hypoxemia.