Noninvasive positive pressure ventilation in patients with acute exacerbations of COPD and varying levels of consciousness

[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.

Physiological effects of high-intensity versus low-intensity noninvasive positive pressure ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease: a randomised controlled trial

Background

High-intensity noninvasive positive pressure ventilation (NPPV) is a novel ventilatory approach to maximally decreasing elevated arterial carbon dioxide tension (PaCO₂) toward normocapnia with stepwise up-titration of pressure support. We tested whether high-intensity NPPV is more effective than low-intensity NPPV at decreasing PaCO₂, reducing inspiratory effort, alleviating dyspnoea, improving consciousness, and improving NPPV tolerance in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

In this physiological, randomised controlled trial, we assigned 24 AECOPD patients to undergo either high-intensity NPPV (n = 12) or low-intensity NPPV (n = 12). The primary outcome was PaCO₂ 24 h after randomisation. Secondary outcomes included gas exchange other than PaCO₂ 24 h after randomisation, inspiratory effort, dyspnoea, consciousness, NPPV tolerance, patient–ventilator asynchrony, cardiac function, ventilator-induced lung injury (VILI), and NPPV-related adverse events.

Results

Inspiratory positive airway pressure 24 h after randomisation was significantly higher (28.0 [26.0–28.0] vs. 15.5 [15.0–17.5] cmH₂O; p = 0.000) and NPPV duration within the first 24 h was significantly longer (21.8 ± 2.1 vs. 15.3 ± 4.7 h; p = 0.001) in the high-intensity NPPV group. PaCO₂ 24 h after randomisation decreased to 54.0 ± 11.6 mmHg in the high-intensity NPPV group but only decreased to 67.4 ± 10.6 mmHg in the low-intensity NPPV group (p = 0.008). Inspiratory oesophageal pressure swing, oesophageal pressure–time product (PTPes)/breath, PTPes/min, and PTPes/L were significantly lower in the high-intensity group. Accessory muscle use and dyspnoea score 24 h after randomisation were also significantly lower in that group. No significant between-groups differences were observed in consciousness, NPPV tolerance, patient–ventilator asynchrony, cardiac function, VILI, or NPPV-related adverse events.

Conclusions

High-intensity NPPV is more effective than low-intensity NPPV at decreasing elevated PaCO₂, reducing inspiratory effort, and alleviating dyspnoea in AECOPD patients.

Trial registration: ClinicalTrials.gov (NCT04044625; registered 5 August 2019).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01018-4.

Prehospital reversal of profound respiratory acidosis and hypercapnic coma by non-invasive ventilation: a report of two cases

BACKGROUND

In chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure (ARF), non-invasive ventilation (NIV) is generally recommended and has proven its benefits by reducing endotracheal intubation (ETI) rates, intensive care unit (ICU) admissions, complications, and mortality. Choosing between immediate ETI or NIV trial is often difficult when such patients present with an altered mental status. Some guidelines recommend avoiding NIV when consciousness is impaired given the risk of aspiration, and some authors suggest that a pH < 7.25 is highly predictive of NIV failure. Though clinical response to a well-adjusted NIV treatment can be both swift and spectacular, these contraindications probably encourage physicians to proceed to immediate ETI. Some studies indeed report that NIV was not even considered in as many as 60% of patients who might have benefited from this therapy, though ETI related complications might have been avoided had NIV been successfully applied.

CASE PRESENTATION

We report two cases of ARF in COPD patients who were successfully treated by NIV in prehospital setting and avoided ETI despite contraindications (altered mental status with a Glasgow Coma Scale < 8) and failure risk factors (severe respiratory acidosis with pH < 7.25).

CONCLUSION

In COPD patients presenting ARF, NIV trial could be considered even when relative contraindications such as an altered level of consciousness or a severe respiratory acidosis are present.

ISCCM Guidelines for the Use of Non-invasive Ventilation in Acute Respiratory Failure in Adult ICUs

A. ACUTE HYPERCAPNIC RESPIRATORY FAILURE A1. Acute Exacerbation of COPD: Recommendations: NIV should be used in management of acute exacerbation of COPD in patients with acute or acute-on-chronic respiratory acidosis (pH = 7.25-7.35). (1A) NIV should be attempted in patients with acute exacerbation of COPD (pH <7.25 & PaCO2 ≥ 45) before initiating invasive mechanical ventilation (IMV) except in patients requiring immediate intubation. (2A). Lower the pH higher the chance of failure of NIV. (2B) NIV should not to be used routinely in normo- or mildly hyper-capneic patients with acute exacerbation of COPD, without acidosis (pH > 7.35). (2B) A2. NIV in ARF due to Chest wall deformities/Neuromuscular diseases: Recommendations: NIV may be used in patients of ARF due to chest wall deformity/Neuromuscular diseases. (PaCO2 ≥ 45) (UPP) A3. NIV in ARF due to Obesity hypoventilation syndrome (OHS): Recommendations: NIV may be used in AHRF in OHS patients when they present with acute hypercapnic or acute on chronic respiratory failure (pH 45). (3B) NIV/CPAP may be used in obese, hypercapnic patients with OHS and/or right heart failure in the absence of acidosis. (UPP) B.

NIV IN ACUTE HYPOXEMIC RESPIRATORY FAILURE

B1. NIV in Acute Cardiogenic Pulmonary Oedema: Recommendations: NIV is recommended in hospital patients with ARF, due to Cardiogenic pulmonary edema. (1A). NIV should be used in patients with acute heart failure/ cardiogenic pulmonary edema, right from emergency department itself. (1B) Both CPAP and BiPAP modes are safe and effective in patients with cardiogenic pulmonary edema. (1A). However, BPAP (NIV-PS) should be preferred in cardiogenic pulmonary edema with hypercapnia. (3A) B2. NIV in acute hypoxemic respiratory failure: Recommendations: NIV may be used over conventional oxygen therapy in mild early acute hypoxemic respiratory failure (P/F ratio <300 and >200 mmHg), under close supervision. (2B) We strongly recommend against a trial of NIV in patients with acute hypoxemic failure with P/F ratio <150. (2A) B3. NIV in ARF due to Chest Trauma: Recommendations: NIV may be used in traumatic flail chest along with adequate pain relief. (3B) B4. NIV in Immunocompromised Host: Recommendations: In Immunocompromised patients with early ARF, we may consider NIV over conventional oxygen. (2B). B5. NIV in Palliative Care: Recommendations: We strongly recommend use of NIV for reducing dyspnea in palliative care setting. (2A) B6. NIV in post-operative cases: Recommendations: NIV should be used in patients with post-operative acute respiratory failure. (2A) B6a. NIV in abdominal surgery: Recommendations: NIV may be used in patients with ARF following abdominal surgeries. (2A) B6b. NIV in bariatric surgery: Recommendations: NIV may be used in post-bariatric surgery patients with pre-existent OSA or OHS. (3A) B6c. NIV in Thoracic surgery: Recommendations: In cardiothoracic surgeries, use of NIV is recommended post operatively for acute respiratory failure to improve oxygenation and reduce chance of reintubation. (2A) NIV should not be used in patients undergoing esophageal surgery. (UPP) B6d. NIV in post lung transplant: Recommendations: NIV may be used for shortening weaning time and to avoid re-intubation following lung transplantation. (2B) B7. NIV during Procedures (ETI/Bronchoscopy/TEE/Endoscopy): Recommendations: NIV may be used for pre-oxygenation before intubation. (2B) NIV with appropriate interface may be used in patients of ARF during Bronchoscopy/Endoscopy to improve oxygenation. (3B) B8. NIV in Viral Pneumonitis ARDS: Recommendations: NIV cannot be considered as a treatment of choice for patients with acute respiratory failure with H1N1 pneumonia. However, it may be reasonable to use NIV in selected patients with single organ involvement, in a strictly controlled environment with close monitoring. (2B) B9. NIV and Acute exacerbation of Pulmonary Tuberculosis: Recommendations: Careful use of NIV in patients with acute Tuberculosis may be considered, with effective infection control precautions to prevent air-borne transmission. (3B) B10. NIV after planned extubation in high risk patients: Recommendation: We recommend that NIV may be used to wean high risk patients from invasive mechanical ventilation as it reduces re-intubation rate. (2B) B11. NIV for respiratory distress post extubation: Recommendations: We recommend that NIV therapy should not be used to manage respiratory distress post-extubation in high risk patients. (2B) C.

APPLICATION OF NIV

Recommendation: Choice of mode should be mainly decided by factors like disease etiology and severity, the breathing effort by the patient and the operator familiarity and experience. (UPP) We suggest using flow trigger over pressure triggering in assisted modes, as it provides better patient ventilator synchrony. Especially in COPD patients, flow triggering has been found to benefit auto PEEP. (3B) D.

MANAGEMENT OF PATIENT ON NIV

D1. Sedation: Recommendations: A non-pharmacological approach to calm the patient (Reassuring the patient, proper environment) should always be tried before administrating sedatives. (UPP) In patients on NIV, sedation may be used with extremely close monitoring and only in an ICU setting with lookout for signs of NIV failure. (UPP) E.

EQUIPMENT

Recommendations: We recommend that portable bilevel ventilators or specifically designed ICU ventilators with non-invasive mode should be used for delivering Non-invasive ventilation in critically ill patients. (UPP) Both critical care ventilators with leak compensation and bi-level ventilators have been equally effective in decreasing the WOB, RR, and PaCO2. (3B) Currently, Oronasal mask is the most preferred interface for non-invasive ventilation for acute respiratory failure. (3B) F.

WEANING

Recommendations: We recommend that weaning from NIV may be done by a standardized protocol driven approach of the unit. (2B) How to cite this article: Chawla R, Dixit SB, Zirpe KG, Chaudhry D, Khilnani GC, Mehta Y, et al. ISCCM Guidelines for the Use of Non-invasive Ventilation in Acute Respiratory Failure in Adult ICUs. Indian J Crit Care Med 2020;24(Suppl 1):S61-S81.

Early prediction of noninvasive ventilation failure in COPD patients: derivation, internal validation, and external validation of a simple risk score

Background

Early identification of noninvasive ventilation (NIV) failure is a promising strategy for reducing mortality in chronic obstructive pulmonary disease (COPD) patients. However, a risk-scoring system is lacking.

Methods

To develop a scale to predict NIV failure, 500 COPD patients were enrolled in a derivation cohort. Heart rate, acidosis (assessed by pH), consciousness (assessed by Glasgow coma score), oxygenation, and respiratory rate (HACOR) were entered into the scoring system. Another two groups of 323 and 395 patients were enrolled to internally and externally validate the scale, respectively. NIV failure was defined as intubation or death during NIV.

Results

Using HACOR score collected at 1–2 h of NIV to predict NIV failure, the area under the receiver operating characteristic curves (AUC) was 0.90, 0.89, and 0.71 for the derivation, internal-validation, and external-validation cohorts, respectively. For the prediction of early NIV failure in these three cohorts, the AUC was 0.91, 0.96, and 0.83, respectively. In all patients with HACOR score > 5, the NIV failure rate was 50.2%. In these patients, early intubation (< 48 h) was associated with decreased hospital mortality (unadjusted odds ratio = 0.15, 95% confidence interval 0.05–0.39, p < 0.01).

Conclusions

HACOR scores exhibited good predictive power for NIV failure in COPD patients, particularly for the prediction of early NIV failure (< 48 h). In high-risk patients, early intubation was associated with decreased hospital mortality.

Benefits of non-invasive ventilation in acute hypercapnic respiratory failure

Non-invasive ventilation (NIV) with bilevel positive airway pressure is a non-invasive technique, which refers to the provision of ventilatory support through the patient's upper airway using a mask or similar device. This technique is successful in correcting hypoventilation. It has become widely accepted as the standard treatment for patients with hypercapnic respiratory failure (HRF). Since the 1980s, NIV has been used in intensive care units and, after initial anecdotal reports and larger series, a number of randomized trials have been conducted. Data from these trials have shown that NIV is a valuable treatment for HRF. This review aims to explore the principal areas in which NIV can be useful, focusing particularly on patients with acute HRF (AHRF). We will update the evidence base with the goal of supporting clinical practice. We provide a practical description of the main indications for NIV in AHRF and identify the group of patients with hypercapnic failure who will benefit most from the application of NIV.

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.

What Is the Impact of Mildly Altered Consciousness on Acute Hypoxemic Respiratory Failure with Non-invasive Ventilation?

Objective A severely altered level of consciousness (ALC) is considered to be a possible contraindication to non-invasive ventilation (NIV). We investigated the association between mild ALC and NIV failure in patients with hypoxemic respiratory failure. Methods A retrospective study was conducted by reviewing the medical charts of patients with de novo hypoxemic respiratory failure who received NIV treatment. The clinical background and the outcomes of patients with and without ALC were compared. Patients Patients who were admitted to our hospital for acute hypoxemic respiratory failure between July 2011 and May 2015 were included in the present study. Results Sixty-six of the 148 patients had ALC. In comparison to the patients without ALC, the patients with ALC were older (median: 72 vs. 78 years, p=0.02), had a higher Acute Physiology and Chronic Health Evaluation II score (18 vs. 19, p=0.02), and received a higher level of inspiratory pressure (8 cmH2O vs. 8, p<0.01). The median Glasgow Coma Scale score of the patients with ALC was 14 (interquartile range, 11-14). There were no significant differences between the groups in the rates of NIV failure (24% vs. 30%, p=0.4) and in-hospital mortality (13% vs. 16%, p=0.3). Conclusion NIV may be successfully applied to treat acute hypoxemic respiratory failure with mild ALC. NIV may be performed, with careful attention to the appropriate timing for intubation.

How should we monitor patients with acute respiratory failure treated with noninvasive ventilation?

Noninvasive ventilation (NIV) is currently one of the most commonly used support methods in hypoxaemic and hypercapnic acute respiratory failure (ARF). With advancing technology and increasing experience, not only are indications for NIV getting broader, but more severe patients are treated with NIV. Depending on disease type and clinical status, NIV can be applied both in the general ward and in high-dependency/intensive care unit settings with different environmental opportunities. However, it is important to remember that patients with ARF are always very fragile with possible high mortality risk. The delay in recognition of unresponsiveness to NIV, progression of respiratory failure or new-onset complications may result in devastating and fatal outcomes. Therefore, it is crucial to understand that timely action taken according to monitoring variables is one of the key elements for NIV success. The purpose of this review is to outline basic and advanced monitoring techniques for NIV during an ARF episode.

Application of BiPAP through Endotracheal Tube in Comatose Patients with COPD Exacerbation

Objective

To evaluate the effectiveness and safety of using BiPAP through endotracheal tube in comatose Chronic Obstructive Pulmonary Disease (COPD) patients with hypercapnic respiratory failure.

Methods

This is a prospective study done at Department of Chest Medicine, Jinnah Postgraduate Medical Centre, Karachi, during March to June 2017. It included all comatose COPD patients with hypercapnic respiratory failure who had a poor functional status prior to the illness and who did not meet the criteria to be kept on mechanical ventilator. Patients with apnea and other causes of coma were excluded. These patients were applied BiPAP through endotracheal tube and its response on blood gases and neurological status was evaluated.

Results

The success rate of BiPAP through endotracheal tube was 70.5% (31/44). Improvement in Glasgow Coma Scale (GCS) score (p<0.01), pH (p<0.01), and PaCO₂ (<0.01) was observed among the responders following two hours and 24 hours of therapy. No significant difference was found in response with regards to gender, smoking status, prior use of noninvasive ventilation or duration of disease. No complications were observed during the therapy.

Conclusion

In resource poor settings, the use of BiPAP through endotracheal tube can be an effective and safe intervention for comatose COPD patients with hypercapnic respiratory failure.

Non-invasive ventilation in the ED: Whom, When, How?

As emergency physicians, we encounter patients suffering from either hypoxemic and/or hypercarbic respiratory problems on a daily basis. A stepwise approach to solving this problem seems logical from an emergency medicine perspective. Current literature supports the notion that NIV decreases endotracheal intubation rates and, mortality in select patient populations. The key to the success of NIV is patient cooperation and support for the care givers. In this narrative review, non-invasive ventilation (NIV) is discussed in terms of modes of delivery, interface and patient selection, as well as practical considerations.

Mechanical Ventilation: State of the Art

Mechanical ventilation is the most used short-term life support technique worldwide and is applied daily for a diverse spectrum of indications, from scheduled surgical procedures to acute organ failure. This state-of-the-art review provides an update on the basic physiology of respiratory mechanics, the working principles, and the main ventilatory settings, as well as the potential complications of mechanical ventilation. Specific ventilatory approaches in particular situations such as acute respiratory distress syndrome and chronic obstructive pulmonary disease are detailed along with protective ventilation in patients with normal lungs. We also highlight recent data on patient-ventilator dyssynchrony, humidified high-flow oxygen through nasal cannula, extracorporeal life support, and the weaning phase. Finally, we discuss the future of mechanical ventilation, addressing avenues for improvement.

Non invasive ventilation in patients with chronic obstructive pulmonary disease in a hospital and at home

Last two decades, active use of non-invasive ventilation (NIV) has provided a significant improvement in the management of chronic obstructive pulmonary disease (COPD), both in patients with acute exacerbation and in stable patients. Currently, NIV is the first-line treatment for patients with acute exacerbation of COPD and acute hypercapnic respiratory failure. This method of respiratory support is also effective after extubation, as it could facilitate weaning from the ventilator and affects positively prevention and treatment of postextubation respiratory failure. Also, NIV has been successfully used in co-morbidity of COPD and sleep apnea syndrome, COPD and pneumonia, and in early postoperative period after thoracic surgery. NIV can be used in COPD patients with chronic respiratory failure. Long-term NIV at home is more reasonable in patients with daytime hypercapnia. The most effective strategy of respiratory support in COPD is thought to be decrease in the partial pressure of carbon dioxide in the arterial blood, i.e. high-intensity NIV. Currently available portable non-invasive ventilators could improve significantly physical activity of patients with severe COPD.

Early use of noninvasive techniques for clearing respiratory secretions during noninvasive positive-pressure ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease and hypercapnic encephalopathy: A prospective cohort study

Noninvasive positive-pressure ventilation (NPPV) might be superior to conventional mechanical ventilation (CMV) in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPDs). Inefficient clearance of respiratory secretions provokes NPPV failure in patients with hypercapnic encephalopathy (HE). This study compared CMV and NPPV combined with a noninvasive strategy for clearing secretions in HE and AECOPD patients.The present study is a prospective cohort study of AECOPD and HE patients enrolled between October 2013 and August 2015 in a critical care unit of a major university teaching hospital in China.A total of 74 patients received NPPV and 90 patients received CMV. Inclusion criteria included the following: physician-diagnosed AECOPD, spontaneous airway clearance of excessive secretions, arterial blood gas analysis requiring intensive care, moderate-to-severe dyspnea, and a Kelly-Matthay scale score of 3 to 5. Exclusion criteria included the following: preexisting psychiatric/neurological disorders unrelated to HE, upper gastrointestinal bleeding, upper airway obstruction, acute coronary syndromes, preadmission tracheostomy or endotracheal intubation, and urgent endotracheal intubation for cardiovascular, psychomotor agitation, or severe hemodynamic conditions.Intensive care unit participants were managed by NPPV. Participants received standard treatment consisting of controlled oxygen therapy during NPPV-free periods; antibiotics, intravenous doxofylline, corticosteroids (e.g., salbutamol and ambroxol), and subcutaneous low-molecular-weight heparin; and therapy for comorbidities if necessary. Nasogastric tubes were inserted only in participants who developed gastric distension. No pharmacological sedation was administered.The primary and secondary outcome measures included comparative complication rates, durations of ventilation and hospitalization, number of invasive devices/patient, and in-hospital and 1-year mortality rates.Arterial blood gases and sensorium levels improved significantly within 2 hours in the NPPV group with lower hospital mortality, fewer complications and invasive devices/patient, and superior weaning off mechanical ventilation. Mechanical ventilation duration, hospital stay, or 1-year mortality was similar between groups.NPPV combined with a noninvasive strategy to clear secretions during the first 2 hours may offer advantages over CMV in treating AECOPD patients complicated by HE.

Hospital Noninvasive Ventilation Case Volume and Outcomes of Acute Exacerbations of Chronic Obstructive Pulmonary Disease

RATIONALE

Higher hospital case volume may produce local expertise ("practice makes perfect"), resulting in better patient outcomes. Associations between hospital noninvasive ventilation (NIV) case volume and outcomes for patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) are unclear.

OBJECTIVES

To determine associations between total hospital NIV case volume for all indications and NIV failure and hospital mortality among patients with acute exacerbations of COPD.

METHODS

Using the 2011 California State Inpatient Database and multivariable hierarchical logistic regression, we calculated hospital-level risk-adjusted rates for NIV failure (progression from NIV to invasive mechanical ventilation) and hospital mortality among patients with acute exacerbations of COPD.

MEASUREMENTS AND MAIN RESULTS

We identified 37,516 hospitalizations for acute exacerbations of COPD in 252 California hospitals in 2011. Total hospital NIV use for all indications ranged from 2 to 565 cases (median, 64; interquartile range, 96). Hospital NIV failure rates for acute exacerbations of COPD ranged from 3.7 to 31.3% (median, 8.5%; interquartile range, 4.2). At the hospital level, higher total hospital NIV case volume was weakly associated with higher hospital NIV failure rates for acute exacerbations of COPD (r = 0.13; P = 0.03). Higher hospital NIV failure rates were weakly associated with higher hospital mortality rates for acute exacerbations of COPD (r = 0.15; P = 0.02), but higher total hospital NIV case volume was not associated with hospital mortality for exacerbations of COPD (r = -0.11; P = 0.08). At the patient level, patients admitted to high-NIV versus low-NIV case-volume hospitals had greater odds of NIV failure (quartile 4 vs. quartile 1 adjusted odds ratio [aOR], 1.95; 95% confidence interval [CI], 1.12-3.40). Compared with initial treatment with invasive mechanical ventilation, NIV failure was associated with higher odds of death (aOR, 1.81; 95% CI, 1.35-2.44). However, admission to high-NIV versus low-NIV case-volume hospitals was not significantly associated with patient in-hospital mortality (quartile 4 vs. quartile 1 aOR, 0.76; 95% CI, 0.57-1.02).

CONCLUSIONS

Despite strong evidence for use of NIV in the management of acute exacerbations of COPD, we observed no significant mortality benefit and higher rates of NIV failure in high-NIV case-volume hospitals. Further investigation of patient selection and hospital factors associated with NIV failure is needed to maximize favorable patient outcomes associated with use of NIV for acute exacerbations of COPD.

Managing Respiratory Failure in Obstructive Lung Disease

Exacerbations of obstructive lung disease are common causes of acute respiratory failure. Short-acting bronchodilators and systemic glucocorticoids are the foundation of pharmacologic management. For patients requiring ventilator support, use of noninvasive ventilation reduces the risk of mortality and progression to invasive mechanical ventilation. Challenges associated with invasive ventilation include ventilator dyssynchrony, air trapping, and dynamic hyperinflation. Careful monitoring and adjustment of ventilatory support parameters helps to optimize the patient-ventilator interaction and minimizes the risk of associated morbidity. Extracorporeal life support is an emerging treatment for refractory hypercapnic respiratory failure associated with obstructive lung disease.

Sleep Neurobiology and Critical Care Illness

The intensive care unit (ICU) environment is not propitious for restoring sleep and many studies have reported that critically ill patients have severe sleep disruptions. However, sleep alterations in critically ill patients are specific and differ significantly from those in ambulatory patients. Polysomnographic patterns of normal sleep are frequently lacking in critically ill patients and the neurobiology of sleep is important to consider regarding alternative methods to quantify sleep in the ICU. This article discusses elements of sleep neurobiology affecting the specificity of sleep patterns and sleep alterations in patients admitted to the ICU.

Noninvasive Ventilation for the Emergency Physician

Noninvasive ventilation (NIV) improves oxygenation and ventilation, prevents endotracheal intubation, and decreases the mortality rate in select patients with acute respiratory failure. Although NIV is used commonly for acute exacerbations of chronic obstructive pulmonary disease and acute cardiogenic pulmonary edema, there are emerging indications for its use in the emergency department. Emergency physicians must be knowledgeable regarding the indications and contraindications for NIV in emergency department patients with acute respiratory failure as well as the means of initiating it and monitoring patients who are receiving it.

[Hypercapnic respiratory failure. Pathophysiology, indications for mechanical ventilation and management]

BACKGROUND

Acute hypercapnic respiratory failure is mostly seen in patients with chronic obstructive pulmonary disease (COPD) and obesity hypoventilation syndrome (OHS). Depending on the underlying cause it may be associated with hypoxemic respiratory failure and places high demands on mechanical ventilation.

OBJECTIVE

Presentation of the current knowledge on indications and management of mechanical ventilation in patients with hypercapnic respiratory failure.

MATERIAL AND METHODS

Review of the literature.

RESULTS

Important by the selection of mechanical ventilation procedures is recognition of the predominant pathophysiological component. In hypercapnic respiratory failure with a pH < 7.35 non-invasive ventilation (NIV) is primarily indicated unless there are contraindications. In patients with severe respiratory acidosis NIV requires a skilled and experienced team and close monitoring in order to perceive a failure of NIV. In acute exacerbation of COPD ventilator settings need a long expiration and short inspiration time to avoid further hyperinflation and an increase in intrinsic positive end-expiratory pressure (PEEP). Ventilation must be adapted to the pathophysiological situation in patients with OHS or overlap syndrome. If severe respiratory acidosis and hypercapnia cannot be managed by mechanical ventilation therapy alone extracorporeal venous CO2 removal may be necessary. Reports on this approach in awake patients are available.

CONCLUSION

The use of NIV is the predominant treatment in patients with hypercapnic respiratory failure but close monitoring is necessary in order not to miss the indications for intubation and invasive ventilation. Methods of extracorporeal CO2 removal especially in awake patients need further evaluation.

Sleep neurobiology and critical care illness

The intensive care unit (ICU) environment is not propitious for restoring sleep and many studies have reported that critically ill patients have severe sleep disruptions. However, sleep alterations in critically ill patients are specific and differ significantly from those in ambulatory patients. Polysomnographic patterns of normal sleep are frequently lacking in critically ill patients and the neurobiology of sleep is important to consider regarding alternative methods to quantify sleep in the ICU. This article discusses elements of sleep neurobiology affecting the specificity of sleep patterns and sleep alterations in patients admitted to the ICU.

Using modeling to inform patient-centered care choices at the end of life

AIM

Advance directives are often under-informed due to a lack of disease-specific prognostic information. Without well-informed advance directives patients may receive default care that is incongruent with their preferences. We aimed to further inform advance care planning in patients with severe chronic obstructive pulmonary disease by estimating outcomes with alternative advance directives.

METHODS

We designed a Markov microsimulation model estimating outcomes for patients choosing between the Full Code advance directive (permitting invasive mechanical ventilation), and the Do Not Intubate directive (only permitting noninvasive ventilation).

RESULTS

Our model estimates Full Code patients have marginally increased one-year survival after admission for severe respiratory failure, but are more likely to be residing in a nursing home and have frequent rehospitalizations for respiratory failure.

CONCLUSION

Patients with severe chronic obstructive pulmonary disease may consider these potential tradeoffs between survival, rehospitalizations and institutionalization when making informed advance care plans and end-of-life decisions. We highlight outcomes research needs for variables most influential to the model's outcomes, including the risk of complications of invasive mechanical ventilation and failing noninvasive mechanical ventilation.

Nasal high-flow oxygen therapy system for improving sleep-related hypoventilation in chronic obstructive pulmonary disease: a case report

INTRODUCTION

Sleep-related hypoventilation should be considered in patients with chronic obstructive pulmonary disease, because appropriate respiratory management during sleep is important for preventing elevation of PaCO2 levels. A nasal high-flow oxygen therapy system using a special nasal cannula can deliver suitably heated and humidified oxygen at up to 60 L/min. Since the oxygen concentration remains a constant independent of minute ventilation, this system is particularly useful in patients with chronic obstructive pulmonary disease who have hypercapnia. This is the first report of sleep-related hypoventilation with chronic obstructive pulmonary disease improving using a nasal high-flow oxygen therapy system.

CASE PRESENTATION

We report the case of a 73-year-old Japanese female who started noninvasive positive-pressure ventilation for acute exacerbation of chronic obstructive pulmonary disease and CO2 narcosis due to respiratory infection. Since she became agitated as her level of consciousness improved, she was switched to a nasal high-flow oxygen therapy system. When a repeat polysomnography was performed while using the nasal high-flow oxygen therapy system, the Apnea Hypopnea Index was 3.7 times/h, her mean SpO2 had increased from 89 to 93%, percentage time with SpO2 ≤ 90% had decreased dramatically from 30.8 to 2.5%, and sleep stage 4 was now detected for 38.5 minutes. As these findings indicated marked improvements in sleep-related hypoventilation, nasal high-flow oxygen therapy was continued at home. She has since experienced no recurrences of CO2 narcosis and has been able to continue home treatment.

CONCLUSIONS

Use of a nasal high-flow oxygen therapy system proved effective in delivering a prescribed concentration of oxygen from the time of acute exacerbation until returning home in a patient with chronic obstructive pulmonary disease, dementia and sleep-related hypoventilation. The nasal high-flow oxygen therapy system is currently used as a device to administer high concentrations of oxygen in many patients with type I respiratory failure, but may also be useful instead of a Venturi mask in patients like ours with type II respiratory failure, additionally providing some positive end-expiratory pressure.

Role of bronchoscopy during non invasive ventilation in hypercapnic respiratory failure

Introduction

Non invasive positive pressure ventilation (NIPPV) is the first line treatment for hypercapnic acute respiratory failure (ARF) secondary to COPD exacerbation in selected patients. Limited data exist supporting the use of fiberoptic bronchoscopy (FOB) during this clinical setting. The aim of this study is to assess the role of FOB during NIPPV in patients with decompensated COPD acute exacerbation.

Methods

This study is a randomized prospective case control pilot study carried out on 50 patients - admitted to critical care units at Alexandria University Hospital, Egypt - suffering from hypercapnic ARF secondary to COPD exacerbation with Kelly Matthay Score from 2 to 4. All patients received NIPPV. Patients were divided randomly into 2 equal groups: group I (cases) (25 patients) was subjected to additional intervention of early FOB during the first 6–12 h from admission while group II (control) (25 patients) received the conventional treatment and NIPPV only. Outcome parameters measured were changes in ABG data, duration of NIPPV, rate of its success, ICU stay and mortality as well as the safety of FOB and possible complications.

Results

No significant difference was detected between the 2 groups regarding the baseline characteristics. No serious complications happened from FOB, and Oxygen desaturation happened in 4/25 patients (16%), Tachycardia in 2/25 patients (8%). In group I, 23 patients (92%) were successfully weaned from NIPPV versus 16 patients (64%) in group II (p = 0.037). Total duration of NIPPV was 28.52 h in group I versus 56.25 h in group II (p = 0.001). Length of ICU stay was 4.84 days in group I versus 8.68 days in group II (p = 0.001). Only 1 patient died in group I versus 3 patients in group II (p = 0.609).

Conclusion

The early application of FOB during NIPPV in patients with ARF due to COPD exacerbation was shown to be safe. Significant improvement in the outcome of patients who underwent FOB was noticed in terms of improved ABG data, shorter duration of NIPPV, higher percentage of success and shorter ICU stay while no significant difference was detected in mortality.

Noninvasive mechanical ventilation in acute respiratory failure: trends in use and outcomes

PURPOSE

Noninvasive ventilation (NIV) had proven benefits in clinical trials that included selected patients admitted to highly skilled centers. Whether these benefits apply to every patient and in everyday practice deserves appraisal. The aim of the study was to assess the use and outcomes of NIV over the last 15 years.

METHODS

Multicenter database study of critically ill patients who required ventilatory support for acute respiratory failure between 1997 and 2011. The impact of first-line NIV on 60-day mortality was evaluated using a marginal structural model. Follow-up was censored on day 60.

RESULTS

Of 3,163 patients, 1,232 (39 %) received NIV. Over the study period, first-line NIV increased from 29 to 42 %, and NIV success rates increased from 69 to 84 %. NIV decreased 60-day mortality [adjusted hazard ratio (aHR), 0.75; 95 % confidence interval (95 % CI), 0.68-0.83; P < 0.0001]. This protective effect was observed in patients with acute-on-chronic respiratory failure (aHR, 0.71; 95 % CI, 0.57-0.90; P = 0.004), but not in patients with cardiogenic pulmonary edema (aHR, 0.85; 95 % CI, 0.70-1.03; P = 0.10) or in patients with hypoxemic ARF, either immunocompetent (aHR, 1.18; 95 % CI, 0.87-1.59; P = 0.30) or immunocompromised (aHR, 0.89; 95 % CI, 0.70-1.13; P = 0.35). NIV failure was an independent time-dependent risk factor for mortality (aHR, 4.2; 95 % CI, 2.8-6.2; P < 0.0001).

CONCLUSIONS

The use of NIV increased steadily over the study period. First-line NIV was associated with better 60-day survival and fewer ICU-acquired infections compared to first-line intubation. Survival benefits from NIV occurred only in patients with acute-on-chronic respiratory failure and immunocompromised patients.

[Ventilation strategies for chronic obstructive pulmonary disease]

Chronic obstructive pulmonary disease (COPD) is considered to be one of the most frequent pulmonary diseases in industrialized countries. Non-invasive ventilation (NIV) is the first choice therapy in acute exacerbations of chronic hypercapnic respiratory failure (AE-COPD). Effective delivery of NIV requires a specialized interdisciplinary team with sufficient monitoring. NIV is delivered as assisted positive pressure ventilation where high inspiratory flow and peak pressure are required. The external positive end expiratory pressure (PEEP) should be adjusted to the intrinsic PEEP. Criteria of success are improvement in the clinical, especially neurological condition as well as improvement of pH and PaCO(2). Patients with a pH between 7.25 and 7.35 have demonstrated most benefit from NIV. In cases of patients not responding to NIV endotracheal intubation should be initiated in a timely manner. Assisted ventilation modes are preferred over controlled ventilation modes in intubated COPD patients. Settings of respirators have to be aimed at a reduction of intrinsic PEEP and dynamic hyperinflation. This includes sufficient external PEEP, long expiration times and low respiratory frequencies even allowing for permissive hypercapnia.

Content Validity of the Comprehensive ICF Core Set for Chronic Obstructive Pulmonary Diseases: An International Delphi Survey

INTRODUCTION

The "Comprehensive ICF Core Set for Chronic Obstructive Pulmonary Diseases (COPD)" is an application of the International Classification of Functioning, Disability and Health (ICF) and represents the typical spectrum of problems in functioning of patients with COPD. The objective of this study was to validate this ICF Core Set from the perspective of physicians.

MATERIALS AND METHODOLOGY

Physicians experienced in COPD treatment were asked about the patients' problems treated by physicians in patients with COPD in a three-round electronic mail survey using the Delphi technique. Responses were linked to the ICF.

RESULTS

Seventy-six physicians in 44 countries gave a total of 1330 responses that were linked to 148 different ICF categories. Nine ICF categories were not represented in the Comprehensive ICF Core Set for COPD although at least 75% of the participants have rated them as important. Nineteen concepts were linked to the not yet developed ICF component personal factors and seventeen concepts were not covered by the ICF.

CONCLUSION

The high percentage of ICF categories represented in the ICF Core Set for COPD indicates satisfactory content validity from the perspective of the physicians. However, some issues were raised that were not covered and need to be investigated further.

Noninvasive mechanical ventilation with average volume assured pressure support (AVAPS) in patients with chronic obstructive pulmonary disease and hypercapnic encephalopathy

BACKGROUND

Non-invasive mechanical ventilation (NIV) in patients with acute respiratory failure has been traditionally determined based on clinical assessment and changes in blood gases, with NIV support pressures manually adjusted by an operator. Bilevel positive airway pressure-spontaneous/timed (BiPAP S/T) with average volume assured pressure support (AVAPS) uses a fixed tidal volume that automatically adjusts to a patient's needs. Our study assessed the use of BiPAP S/T with AVAPS in patients with chronic obstructive pulmonary disease (COPD) and hypercapnic encephalopathy as compared to BiPAP S/T alone, upon immediate arrival in the Emergency-ICU.

METHODS

We carried out a prospective interventional match-controlled study in Guayaquil, Ecuador. A total of 22 patients were analyzed. Eleven with COPD exacerbations and hypercapnic encephalopathy with a Glasgow Coma Scale (GCS) <10 and a pH of 7.25-7.35 were assigned to receive NIV via BiPAP S/T with AVAPS. Eleven patients were selected as paired controls for the initial group by physicians who were unfamiliar with our study, and these patients were administered BiPAP S/T. Arterial blood gases, GCS, vital signs, and ventilatory parameters were then measured and compared between the two groups.

RESULTS

We observed statistically significant differences in favor of the BiPAP S/T + AVAPS group in GCS (P = .00001), pCO(2) (P = .03) and maximum inspiratory positive airway pressure (IPAP) (P = .005), among others. However, no significant differences in terms of length of stay or days on NIV were observed.

CONCLUSIONS

BiPAP S/T with AVAPS facilitates rapid recovery of consciousness when compared to traditional BiPAP S/T in patients with chronic obstructive pulmonary disease and hypercapnic encephalopathy.

TRIAL REGISTRATION

Current Controlled Trials application ref is ISRCTN05135218.

Positive outcome of average volume-assured pressure support mode of a Respironics V60 Ventilator in acute exacerbation of chronic obstructive pulmonary disease: a case report

INTRODUCTION

We were able to treat a patient with acute exacerbation of chronic obstructive pulmonary disease who also suffered from sleep-disordered breathing by using the average volume-assured pressure support mode of a Respironics V60 Ventilator (Philips Respironics: United States). This allows a target tidal volume to be set based on automatic changes in inspiratory positive airway pressure. This removed the need to change the noninvasive positive pressure ventilation settings during the day and during sleep. The Respironics V60 Ventilator, in the average volume-assured pressure support mode, was attached to our patient and improved and stabilized his sleep-related hypoventilation by automatically adjusting force to within an acceptable range.

CASE PRESENTATION

Our patient was a 74-year-old Japanese man who was hospitalized for treatment due to worsening of dyspnea and hypoxemia. He was diagnosed with acute exacerbation of chronic obstructive pulmonary disease and full-time biphasic positive airway pressure support ventilation was initiated. Our patient was temporarily provided with portable noninvasive positive pressure ventilation at night-time following an improvement in his condition, but his chronic obstructive pulmonary disease again worsened due to the recurrence of a respiratory infection. During the initial exacerbation, his tidal volume was significantly lower during sleep (378.9 ± 72.9mL) than while awake (446.5 ± 63.3mL). A ventilator that allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range was attached in average volume-assured pressure support mode, improving his sleep-related hypoventilation, which is often associated with the use of the Respironics V60 Ventilator. Polysomnography performed while our patient was on noninvasive positive pressure ventilation revealed obstructive sleep apnea syndrome (apnea-hypopnea index = 14), suggesting that his chronic obstructive pulmonary disease was complicated by obstructive sleep apnea syndrome.

CONCLUSION

In cases such as this, in which patients with severe acute respiratory failure requiring full-time noninvasive positive pressure ventilation therapy also show sleep-disordered breathing, different ventilator settings must be used for waking and sleeping. On such occasions, the Respironics V60 Ventilator, which is equipped with an average volume-assured pressure support mode, may be useful in improving gas exchange and may achieve good patient compliance, because that mode allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range whenever ventilation falls below target levels.

Vibration response imaging: a novel noninvasive tool for evaluating the initial therapeutic effect of noninvasive positive pressure ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND

The popular methods for evaluating the initial therapeutic effect (ITE) of noninvasive positive pressure ventilation (NPPV) can only roughly reflect the therapeutic outcome of a patient's ventilation because they are subjective, invasive and time-delayed. In contrast, vibration response imaging (VRI) can monitor the function of a patient's ventilation over the NPPV therapy in a non-invasive manner. This study aimed to investigate the value of VRI in evaluating the ITE of NPPV for patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

METHODS

Thirty-six AECOPD patients received VRI at three time points: before NPPV treatment (T1), at 15 min of NPPV treatment (T2), and at 15 min after the end of NPPV treatment (T4). Blood gas analysis was also performed at T1 and at 2 hours of NPPV treatment (T3). Thirty-nine healthy volunteers also received VRI at T1 and T2. VRI examination at the time point T2 in either the patients or volunteers did not require any interruption of the on-going NPPV. The clinical indices at each time point were compared between the two groups. Moreover, correlations between the PaCO2 changes (T3 vs T1) and abnormal VRI scores (AVRIS) changes (T2 vs T1) were analyzed.

RESULTS

No significant AVRIS differences were found between T1 and T2 in the healthy controls (8.51 ± 3.36 vs. 8.53 ± 3.57, P > 0.05). The AVRIS, dynamic score, MEF score and EVP score showed a significant decrease in AECOPD patients at T2 compared with T1 (P < 0.05), but a significant increase at T4 compared with T2 (P < 0.05). We also found a positive correlation (R2 = 0.6399) between the PaCO2 changes (T3 vs T1) and AVRIS changes (T2 vs T1).

CONCLUSIONS

VRI is a promising noninvasive tool for evaluating the initial therapeutic effects of NPPV in AECOPD patients and predicting the success of NPPV in the early stage.

Role of BiPAP applied through endotracheal tube in unconscious patients suffering from acute exacerbation of COPD: a pilot study

BACKGROUND AND OBJECTIVES

Mechanical ventilation is the recommended treatment in unconscious patients with acute exacerbation of chronic obstructive pulmonary disease (COPD) and hypercapenic respiratory failure. But, in resource-poor countries, many of these patients are not able to afford this treatment due to financial constraints. The main aim of this study was to evaluate the usefulness, safety and cost-effectiveness of bilevel positive airway pressure (BiPAP) applied via endotracheal tube in such patients.

METHODS

Twenty patients with acute exacerbation of COPD and altered sensorium, who were unable to afford ventilatory support, were intubated and BiPAP therapy was provided to these patients through the endotracheal tube. The outcome of these patients was studied.

RESULTS

The BiPAP success rate and hospital mortality were 85% (17/20) and 15% (3/20) respectively. BiPAP failure was associated with high sequential organ failure assessment (SOFA) score at the time of admission (P = 0.002). Improvement in Glasgow coma scale (GCS) score (P < 0.001), pH (P = 0.001), PaCO(2) (partial pressure of carbon dioxide) (P < 0.001), respiratory rate (P < 0.001), and SOFA score (P = 0.001) was observed among the responders following 2 hours of therapy. Only one of the responders developed aspiration pneumonitis, as a complication. The daily cost of BiPAP therapy was 8.75 times lower than the average cost of mechanical ventilation.

CONCLUSION

This pilot study reveals that this treatment modality could be a safe, cost-effective and efficacious method of treatment in unconscious patients with acute exacerbation of COPD.

Informing shared decisions about advance directives for patients with severe chronic obstructive pulmonary disease: a modeling approach

OBJECTIVE

To estimate the survival and quality-adjusted life-years (QALYs) of Full Code versus Do Not Intubate (DNI) advance directives in patients with severe chronic obstructive pulmonary disease and to evaluate how patient preferences and place of residence influence these outcomes.

METHODS

A Markov decision model using published data for COPD exacerbation outcomes. The advance directives that were modeled were as follows: DNI, allowing only noninvasive mechanical ventilation, or Full Code, allowing all forms of mechanical ventilation including invasive mechanical ventilation with endotracheal tube (ETT) insertion.

RESULTS

In community-dwellers, Full Code resulted in a greater likelihood of survival and higher QALYs (4-year survival: 23% Full Code, 18% DNI; QALYs: 1.34 Full Code, 1.24 DNI). When considering patient preferences regarding complications, however, if patients were willing to give up >3 months of life expectancy to avoid ETT complications, or >1 month of life expectancy to avoid long-term institutionalization, DNI resulted in higher QALYs. For patients in long-term institutions, DNI resulted in a greater likelihood of survival and higher QALYs (4-year survival: 2% DNI, 1% Full Code; QALYs: 0.29 DNI, 0.24 Full Code). In sensitivity analyses, the model was sensitive to the probabilities of ETT complication and noninvasive mechanical ventilation failure and to patient preferences about ETT complications and long-term institutionalization.

CONCLUSION

Our model demonstrates that patient preferences regarding ETT complications and long-term institutionalization, as well as baseline place of residence, affect the advance directive recommendation when considered in terms of both survival and QALYs. Decision modeling can demonstrate the potential trade-off between survival and quality of life, using patient preferences and disease-specific data, to inform the shared advance directive decision.

Outcomes of noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease in the United States, 1998-2008

RATIONALE

The patterns and outcomes of noninvasive, positive-pressure ventilation (NIPPV) use in patients hospitalized for acute exacerbations of chronic obstructive pulmonary disease (COPD) nationwide are unknown.

OBJECTIVES

To determine the prevalence and trends of noninvasive ventilation for acute COPD.

METHODS

We used data from the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample to assess the pattern and outcomes of NIPPV use for acute exacerbations of COPD from 1998 to 2008.

MEASUREMENTS AND MAIN RESULTS

An estimated 7,511,267 admissions for acute exacerbations occurred from 1998 to 2008. There was a 462% increase in NIPPV use (from 1.0 to 4.5% of all admissions) and a 42% decline in invasive mechanical ventilation (IMV) use (from 6.0 to 3.5% of all admissions) during these years. This was accompanied by an increase in the size of a small cohort of patients requiring transition from NIPPV to IMV. In-hospital mortality in this group appeared to be worsening over time. By 2008, these patients had a high mortality rate (29.3%), which represented 61% higher odds of death compared with patients directly placed on IMV (95% confidence interval, 24-109%) and 677% greater odds of death compared with patients treated with NIPPV alone (95% confidence interval, 475-948%). With the exception of patients transitioned from NIPPV to IMV, in-hospital outcomes were favorable and improved steadily year by year.

CONCLUSIONS

The use of NIPPV has increased significantly over time among patients hospitalized for acute exacerbations of COPD, whereas the need for intubation and in-hospital mortality has declined. However, the rising mortality rate in a small but expanding group of patients requiring invasive mechanical ventilation after treatment with noninvasive ventilation needs further investigation.

A case-based approach to noninvasive positive pressure ventilation

Noninvasive positive pressure ventilation (NIPPV) has revolutionized the concept of mechanical ventilation with the major benefit of avoiding invasive mechanical ventilation in specific situations, thereby preventing associated complications. Noninvasive positive pressure ventilation has emerged as the first line of management of hypercapnic respiratory failure (due to chronic obstructive pulmonary disease and neuromuscular weakness) and cardiogenic pulmonary edema in addition to standard therapy in the acute setting. There is improvement in gas exchange, relief of respiratory muscle fatigue, and clinical outcome with reduced morbidity and mortality. Nevertheless, contraindications and failures need to be identified early, as delaying endotracheal intubation is associated with increased morbidity and mortality. Despite overwhelming evidence to support its use, NIPPV is underused. Residents and hospitalists need to identify NIPPV as a treatment option in acute respiratory failure.

Hypercapnic encephalopathy syndrome: a new frontier for non-invasive ventilation?

According to the classical international guidelines, non-invasive ventilation is contraindicated in hypercapnic encephalopathy syndrome (HES) due to the poor compliance to ventilatory treatment of confused/agitated patients and the risk of aspirative pneumonia related to lack of airways protection. As a matter of fact, conventional mechanical ventilation has been recommended as "golden standard" in these patients. However, up to now there are not controlled data that have demonstrated in HES the advantage of conventional mechanical ventilation vs non-invasive ventilation. In fact, patients with altered mental status have been systematically excluded from the randomised and controlled trials performed with non-invasive ventilation in hypercapnic acute respiratory failure. Recent studies have clearly demonstrated that an initial cautious NPPV trial in selected HES patients may be attempt as long as there are no other contraindications and the technique is provided by experienced caregivers in a closely monitored setting where ETI is always readily available. The purpose of this review is to report the physiologic rationale, the clinical feasibility and the still open questions about the careful use of non-invasive ventilation in HES as first-line ventilatory strategy in place of conventional mechanical ventilation via endotracheal intubation.

A theoretical decision model to help inform advance directive discussions for patients with COPD

Background

Advance directives (AD) may promote preference-concordant care yet are absent in many patients with Chronic Obstructive Pulmonary Disease (COPD). In order to begin to inform AD discussions between clinicians and COPD patients, we constructed a decision tree to estimate the impact of alternative AD decisions on both quality and quantity of life (quality adjusted life years, QALYs).

Methods

Two aspects of the AD were considered, Do Not Intubate (DNI; i.e., no invasive mechanical ventilation) and Full Code (i.e., may use invasive mechanical ventilation). Model parameters were based on published estimates. Our model follows hypothetical patients with COPD to evaluate the effect of underlying COPD severity and of hypothetical patient-specific preferences (about long-term institutionalization and complications from invasive mechanical ventilation) on the recommended AD.

Results

Our theoretical model recommends endorsing the Full Code advance directive for patients who do not have strong preferences against having a potential complication from intubation (ETT complications) or being discharged to a long-term ECF. However, our model recommends endorsing the DNI advance directive for patients who do have strong preferences against having potential complications of intubation and are were willing to tradeoff substantial amounts of time alive to avoid ETT complications or permanent institutionalization. Our theoretical model also recommends endorsing the DNI advance directive for patients who have a higher probability of having complications from invasive ventilation (ETT).

Conclusions

Our model suggests that AD decisions are sensitive to patient preferences about long-term institutionalization and potential complications of therapy, particularly in patients with severe COPD. Future work will elicit actual patient preferences about complications of invasive mechanical ventilation, and incorporate our model into a clinical decision support to be used for actual COPD patients facing AD decisions.

Another step for noninvasive ventilation in chronic obstructive pulmonary disease patients!

The use of noninvasive positive pressure ventilation (NPPV) in chronic obstructive pulmonary disease (COPD) patients who are not eligible for the technique because of their incapability to spontaneously eliminate accumulated secretions associated with hypercapnic encephalopathy is not recommended and is often considered a contraindication. In a case-control study, an experienced team reported the feasibility and safety of the use of NPPV with early fibreoptic bronchoscopy in selected acutely decompensated COPD patients with hypercapnic encephalopathy, and reported the patients' inability to spontaneously clear copious secretions. The reported data suggest that this innovative therapeutic may be considered as a potential alternative to endotracheal intubation.

Early fiberoptic bronchoscopy during non-invasive ventilation in patients with decompensated chronic obstructive pulmonary disease due to community-acquired-pneumonia

INTRODUCTION

Inefficient clearance of copious respiratory secretion is a cause of non-invasive positive pressure ventilation (NPPV) failure, especially in chronic respiratory patients with community-acquired-pneumonia (CAP) and impaired consciousness. We postulated that in such a clinical scenario, when intubation and conventional mechanical ventilation (CMV) are strongly recommended, the suction of secretions with fiberoptic bronchoscopy (FBO) may increase the chance of NPPV success. The objective of this pilot study was, firstly, to verify the safety and effectiveness of early FBO during NPPV and, secondly, to compare the hospital outcomes of this strategy versus a CMV-based strategy in patients with decompensated chronic obstructive pulmonary disease (COPD) due to CAP who are not appropriate candidates for NPPV because of inefficient mucous clearance and hypercapnic encephalopathy (HE).

METHODS

This is a 12-month prospective matched case-control study performed in one respiratory semi-intensive care unit (RSICU) with expertise in NPPV and in one intensive care unit (ICU). Fifteen acutely decompensated COPD patients with copious secretion retention and HE due to CAP undergoing NPPV in RSICU, and 15 controls (matched for arterial blood gases, acute physiology and chronic health evaluation score III, Kelly-Matthay scale, pneumonia extension and severity) receiving CMV in the ICU were studied.

RESULTS

Two hours of NPPV significantly improved arterial blood gases, Kelly and cough efficiency scores without FBO-related complications. NPPV avoided intubation in 12/15 patients (80%). Improvement in arterial blood gases was similar in the two groups, except for a greater PaO2/fraction of inspired oxygen ratio with CMV. The rates of overall and septic complications, and of tracheostomy were lower in the NPPV group (20%, 20%, and 0%) versus the CMV group (80%, 60%, and 40%; P < 0.05). Hospital mortality, duration of hospitalisation and duration of ventilation were similar in the two groups.

CONCLUSIONS

In patients with decompensated COPD due to CAP who are candidates for CMV because of HE and inability to clear copious secretions, NPPV with early therapeutic FBO performed by an experienced team is a feasible, safe and effective alternative strategy.

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.

Noninvasive and invasive ventilation in acute respiratory failure associated with bronchiectasis

PURPOSE

To describe the outcomes of patients with bronchiectasis and acute respiratory failure (ARF) treated with noninvasive ventilation (NIV) and invasive mechanical ventilation (IMV) after a failure of conservative measures, and to identify the predictors of hospital mortality and NIV failure.

METHODS

Retrospective review of bronchiectatic patients on NIV (n = 31) or IMV (n = 26) for ARF over 8 years in a medical intensive care unit (ICU) experienced in NIV.

RESULTS

At baseline, the NIV group had more patients with acute exacerbations without identified precipitating factors (87.1 vs. 34.6%, p < 0.001), higher pH (mean 7.25 vs. 7.18, p = 0.008) and PaO(2)/FiO(2) ratio (mean 249.4 vs. 173.2, p = 0.02), and a trend towards a lower APACHE II score (mean 25.3 vs. 28.4, p = 0.07) than the IMV group. There was no difference in hospital mortality between the two groups (25.8 vs. 26.9%, p > 0.05). The NIV failure rate (need for intubation or death in the ICU) was 32.3%. Using logistic regression, the APACHE II score was the only predictor of hospital mortality (OR 1.19 per point), and the PaO(2)/FiO(2) ratio was the only predictor of NIV failure (OR 1.02 per mmHg decrease).

CONCLUSIONS

The hospital mortality of patients with bronchiectasis and ARF approximates 25% and is predicted by the APACHE II score. When selectively applied, NIV fails in one-third of the patients, and this is predicted by hypoxemia. Our findings call for randomised controlled trials to compare NIV versus IMV in such patients.

[Non-invasive ventilation]

Non-invasive ventilation (NIV) is a technique that delivers mechanical ventilation avoiding side effects and complications associated with endotracheal intubation and invasive mechanical ventilation. This technique has proved to be effective in different types of respiratory failure. In this article, the authors revise the advantages and limitations of NIV, interfaces used and indications in acute and acute-on-chronic respiratory failure.