BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults

Systemic Thrombolysis Therapy is Associated With Improved Outcomes Among Patients With Acute Pulmonary Embolism and Respiratory Failure

BACKGROUND

Thrombolytic therapy is widely accepted for massive pulmonary embolism (PE) due to the high mortality risk associated with standard anticoagulation alone. Its role in submassive PE, however, has remained controversial. We aimed to evaluate whether the selective use of systemic thrombolytic therapy with intravenous tissue plasminogen activator (IV-tPA) improves the survival of patients with submassive PE at increased risk for clinical deterioration.

METHODS

A total of 184 consecutive patients diagnosed with acute PE by chest thoracic angiography (CTA) were included in a retrospective study. Pulmonary artery obstruction and right/left ventricular dysfunction were evaluated by CTA and echocardiography. Medical history and simplified PE Severity Index (sPESI) were assessed at diagnosis. Hemodynamic and respiratory status were recorded at diagnosis, admission to pulmonary unit and prior to thrombolytic therapy. Patient survival was assessed at 30 of 90 days from diagnosis by CTA.

RESULTS

All low risk patients (36%) per sPESI survived. Among the 117 remaining patients, 31% received IV-tPA. Respiratory failure was associated with decreased age-adjusted survival (P = 0.005). Among patients with respiratory failure selected for IV-tPA, age-adjusted survival was improved significantly compared to others (P = 0.043).

CONCLUSIONS

Thrombolytic therapy for hemodynamically stable PE patients with respiratory failure may improve survival.

TRIAL REGISTRATION

MMC-0216-14.

The benefits of non-invasive ventilation for Community-Acquired Pneumonia: A meta-analysis

BACKGROUND

There is an observed international increase in NIV application as an alternative to endotracheal intubation in non-COPD patients admitted with community acquired pneumonia despite the lack of strong evidence for its use. The aim of this study is the meta-analysis of data from randomised-controlled trials on the effectiveness of non-invasive ventilation versus standard medical care in adults admitted with severe community-acquired pneumonia.

METHODS

Monthly electronic searches on CENTRAL and MEDLINE were performed between September 2017 and October 2019. Only randomized controlled-trials comparing non-invasive ventilation to standard medical care for the treatment of community-acquired pneumonia in adults were eligible for inclusion. The primary outcomes were the rate of endotracheal intubation (ETI) and the proportion of patients meeting the criteria of ETI as defined by the investigators. Secondary outcomes were the ICU and hospital mortality rate. Study eligibility was independently assessed by two investigators. The risk of bias of included studies was assessed using Cochrane's Risk of bias Tool.

RESULTS

Four RCTs involving a total of 218 participants were eligible for inclusion. Results from the meta-analysis showed that NIV significantly reduced rate of ETI (RR = 0.46, 95% CI [0.26, 0.79]), the proportion of patients that met the criteria for ETI (RR = 0.28, 95% CI[0.16, 0.49]) and ICU mortality rate (RR = 0.3, 95% CI[0.09, 0.93]). No significant effect on hospital mortality rate was found (RR = 0.44, 95% CI [0.05, 3.67]). The authors rated quality of evidence based on GRADE criteria as 'Moderate' for the rate of intubation and proportion of patients meeting ETI criteria outcomes, but quality of evidence for ICU and hospital mortality rate as 'Low'.

CONCLUSIONS

This study provides evidence supporting the use of NIV as potential means of avoiding endotracheal intubation and ICU mortality, in patients with acute respiratory failure due to CAP in the critical care setting. However, there is need for further larger international studies.

Variables predicting weaning outcome in prolonged mechanically ventilated tracheotomized patients: a retrospective study

Background

Several studies have assessed predictors of weaning and extubation outcome in short-term mechanically ventilated patients, but there are only few studies on predictors of weaning from prolonged mechanical ventilation.

Methods

Retrospective, single-center, observational study at a specialized national weaning center in Germany. Patients’ medical records were reviewed to obtain data on demographics, comorbidities, respiratory indices, and the result of a prospectively documented, standardized spontaneous breathing trial (SBT) upon admission to the weaning center. Respiratory indices assessed were the ventilatory ratio (VR) and parameters derived from calculated mechanical power (MP). Predictors associated with failure of prolonged weaning and failure of the SBT were assessed using a binary logistic regression model.

Results

A total of 263 prolonged mechanically ventilated, tracheotomized patients, treated over a 5-year period were analyzed. After 3 weeks of mechanical ventilation, patients with unsuccessful weaning failed a SBT more frequently and showed significantly increased values for inspiratory positive airway pressure, driving pressure, VR, absolute MP, and MP normalized to predicted body weight and dynamic lung-thorax compliance (LTC-MP). In the logistic regression analyses, variables independently correlated with weaning failure were female gender (adjusted odds ratio 0.532 [95% CI 0.291–0.973]; p = 0.040), obesity (body mass index ≥ 30 kg/m²) (2.595 [1.210–5.562]; p = 0.014), COPD (3.209 [1.563–6.589]; p = 0.002), LTC-MP (3.470 [1.067–11.284]; p = 0.039), P_aCO₂ on mechanical ventilation (1.101 [95% CI 1.034–1.173]; p = 0.003), and failure of the SBT (4.702 [2.250–9.825]; p < 0.001). In addition, female gender (0.401 [0.216–0.745]; p = 0.004), LTC-MP (3.017 [1.027–8.862]; p = 0.046), and P_aCO₂ on mechanical ventilation (1.157 [1.083–1.235]; p < 0.001) were independent risk factors for an unsuccessful SBT.

Conclusions

In the present study, the derived predictors of weaning point to a crucial role of the workload imposed on respiratory muscles during spontaneous breathing. Mechanical power normalized to lung-thorax compliance was independently correlated with weaning outcome and may identify patients at high risk for weaning failure.

Management of hypoxaemia in the critically ill patient

Hypoxaemia is a common presentation in critically ill patients, with the potential for severe harm if not addressed appropriately. This review provides a framework to guide the management of any hypoxaemic patient, regardless of the clinical setting. Key steps in managing such patients include ascertaining the severity of hypoxaemia, the underlying diagnosis and implementing the most appropriate treatment. Oxygen therapy can be delivered by variable or fixed rate devices, and non-invasive ventilation; if patients deteriorate they may require tracheal intubation and mechanical ventilation. Early critical care team involvement is a key part of this pathway. Specialist treatments for severe hypoxaemia can only be undertaken on an intensive care unit and this field is developing rapidly as trial results become available. It is important that each new scenario is approached in a structured manner with an open diagnostic mind and a clear escalation plan.

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.

A comparison of three strategies for withdrawal of noninvasive ventilation in chronic obstructive pulmonary disease with acute respiratory failure: Randomized trial

Background:

The optimal strategy for the withdrawal of noninvasive ventilation (NIV) remains unknown. This study was planned to compare three different strategies for the withdrawal of NIV among patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with hypercapnic respiratory failure (HcRF).

Materials and Methods:

Patients with AECOPD with HcRF who improved on NIV were randomized into three groups – immediate withdrawal (Group A), stepwise reduction of pressure support (Group B), and stepwise reduction of duration (Group C) of NIV. The probability of successful withdrawal was compared among the groups.

Results:

This study included 90 patients (males – 86.6%) with a mean (±standard deviation [SD]) age of 59.9 ± 8.3 years. The mean (±SD) pH and PaCO₂ at admission were 7.23 ± 0.04 and 84.4 ± 12.0 mm Hg, respectively. The duration of NIV received before randomization was 31.6 ± 9.2 h with maximum inspiratory positive airway pressure and expiratory positive airway pressure of 17.6 ± 2.7 cm H₂O and 7.4 ± 1.4 cm H₂O, respectively. NIV was successfully withdrawn in 23/30 (76.6%) in Group A, 27/30 (90%) in Group B, and 26/30 (86.6%) in Group C (P = 0.31). The total duration of NIV use and length of hospital stay was lower in Group A and B as compared to Group C (P = 0.001).

Conclusions:

Immediate withdrawal of the NIV after recovery of respiratory failure among patients with exacerbation of COPD is feasible. Immediate withdrawal did not increase the risk of weaning failure from the NIV.

ERS International Congress, Madrid, 2019: highlights from the Respiratory Intensive Care Assembly

The Respiratory Intensive Care Assembly of the European Respiratory Society is delighted to present the highlights from the 2019 International Congress in Madrid, Spain. We have selected four sessions that discussed recent advances in a wide range of topics: from acute respiratory failure to cough augmentation in neuromuscular disorders and from extra-corporeal life support to difficult ventilator weaning. The subjects are summarised by early career members in close collaboration with the Assembly leadership. We aim to give the reader an update on the most important developments discussed at the conference. Each session is further summarised into a short list of take-home messages.

Respiratory Involvement in Patients with Neuromuscular Diseases: A Narrative Review

Respiratory muscle weakness is a major cause of morbidity and mortality in patients with neuromuscular diseases (NMDs). Respiratory involvement in NMDs can manifest broadly, ranging from milder insufficiency that may affect only sleep initially to severe insufficiency that can be life threatening. Patients with neuromuscular diseases exhibit very often sleep-disordered breathing, which is frequently overlooked until symptoms become more severe leading to irreversible respiratory failure necessitating noninvasive ventilation (NIV) or even tracheostomy. Close monitoring of respiratory function and sleep evaluation is currently the standard of care. Early recognition of sleep disturbances and initiation of NIV can improve the quality of life and prolong survival. This review discusses the respiratory impairment during sleep in patients with NMDs, the diagnostic tools available for early recognition of sleep-disordered breathing and the therapeutic options available for overall respiratory management of patients with NMDs.

The use of non-invasive ventilation in an exacerbation of chronic obstructive pulmonary disease: a case study

This article aims to assist nurses and other health professionals to care for patients who have type 2 respiratory failure as a result of chronic obstructive pulmonary disease, and who require non-invasive ventilation. It outlines findings of a case study that are commonplace in the acute medical setting and aims to highlight important factors that impact on patient care and patient outcome, and to help nursing staff to implement recommended and best practices.

Not All COPD Patients Benefit from Prophylactic Noninvasive Ventilation After Scheduled Extubation: An Exploratory Study

Background

Prophylactic noninvasive ventilation (NIV) after scheduled extubation can benefit patients with chronic respiratory disorders, among which chronic obstructive pulmonary disease (COPD) is a significant example. However, it is not known whether all COPD patients benefit from prophylactic NIV.

Methods

We performed a post hoc analysis of prospectively collected data. COPD patients who successfully completed a spontaneous breathing trial were enrolled. In the prophylactic NIV group, NIV was applied immediately after extubation. In the usual care group, conventional oxygen therapy was used. Patients were followed up to 90 days post-extubation.

Results

Among patients with PaCO₂ > 45 mmHg, 128 and 40 received prophylactic NIV and usual care, respectively. Prophylactic NIV led to lower rates of re-intubation (4% vs 30% at 72 h and 11% vs 35% at 7 days, both p < 0.01) and hospital mortality (18% vs 40%, p < 0.01) than usual care. The proportion of 90-day mortality was also lower in the prophylactic NIV group (log rank test, p = 0.04). Among patients with PaCO₂ ≤ 45 mmHg, 32 and 21 received prophylactic NIV and usual care, respectively. In this cohort however, prophylactic NIV neither reduced re-intubation (6% vs 5% at 72 h, p > 0.99, and 9% vs 14% at 7 days, p = 0.67) nor hospital mortality (19% vs 24%, p = 0.74). The proportion of 90-day mortality did not differ between the two groups (log rank test, p = 0.79).

Conclusion

This exploratory study shows that prophylactic NIV benefits COPD patients with PaCO₂ > 45 mmHg, but it may not benefit those with PaCO₂ ≤ 45 mmHg. Further study with a larger sample size is required to confirm this.

Effect of oxygen therapy on the risk of mechanical ventilation in emergency acute pulmonary edema patients

OBJECTIVE

We investigated the effects of hyperoxemia on morbidity and mortality in acute cardiogenic pulmonary edema (ACPE).

METHODS

We conducted a retrospective cohort study of patients in our emergency department (ED) with ACPE who received arterial blood gases. Patients were classified based on the first PaO2 as hypoxemic (<75 mmHg), normoxemic (75-100 mmHg) and hyperoxemic (>100 mmHg). The primary outcome was the rates of mechanical ventilation (MV). We also reported adjusted odds ratios (AOR) and their 95% confidence intervals (CI) of the primary outcome after adjusting for predictors of MV determined a priori. Secondary outcomes were median hospital length of stay (LOS) and in-hospital mortality.

RESULTS

We recruited 335 patients; 34.0% had hyperoxemia. The rates of normoxemia and hypoxemia were 27.5% and 38.5%, respectively. The rates of MV were: hypoxemic 60/129 (46.5%) vs. normoxemic 41/92 (44.6%) vs. hyperoxemic 50/114 (43.9%); P = 0.62. The AORs for MV for the hyperoxemic and hypoxemic groups (reference: normoxemic group) were 0.98 (95% CI: 0.53-1.79) and 1.38 (95% CI: 0.77-2.48), respectively. Intubation rates for the groups were: hypoxemic 15/129 (11.6%) vs. normoxemic 6/92 (6.5%) vs. hyperoxemic 12/114 (10.6%); P = 0.43. The secondary outcomes were comparable among the groups. In-hospital mortality rates were: hypoxemic 6/129 (4.7%) vs. 6/92 (6.5%) vs. 10/114 (8.8%); P = 0.42.

CONCLUSION

Our exploratory study did not report effects on mechanical ventilation, median hospital LOS and in-hospital mortality from hyperoxemia compared to hypoxemic and normoxemic ED patients with ACPE. Further studies are warranted to prove or disprove our findings.

Trends in the Use and Outcomes of Mechanical Ventilation among Patients Hospitalized with Acute Exacerbations of COPD in Spain, 2001 to 2015

(1) Background: We examine trends (2001–2015) in the use of non-invasive ventilation (NIV) and invasive mechanical ventilation (IMV) among patients hospitalized for acute exacerbation of chronic obstructive pulmonary disease (AE-COPD). (2) Methods: Observational retrospective epidemiological study, using the Spanish National Hospital Discharge Database. (3) Results: We included 1,431,935 hospitalizations (aged ≥40 years) with an AE-COPD. NIV use increased significantly, from 1.82% in 2001–2003 to 8.52% in 2013–2015, while IMV utilization decreased significantly, from 1.39% in 2001–2003 to 0.67% in 2013–2015. The use of NIV + invasive mechanical ventilation (IMV) rose significantly over time (from 0.17% to 0.42%). Despite the worsening of clinical profile of patients, length of stay decreased significantly over time in all types of ventilation. Patients who received only IMV had the highest in-hospital mortality (IHM) (32.63%). IHM decreased significantly in patients with NIV + IMV, but it remained stable in those receiving isolated NIV and isolated IMV. Factors associated with use of any type of ventilatory support included female sex, lower age, and higher comorbidity. (4) Conclusions: We found an increase in NIV use and a decline in IMV utilization to treat AE-COPD among hospitalized patients. The IHM decreased significantly over time in patients who received NIV + IMV, but it remained stable in patients who received NIV or IMV in isolation.

Predictors of Long-term Mortality after Hospitalization for Severe COPD Exacerbation

Introduction:Chronic obstructive pulmonary disease (COPD) is a global health problem resulting in significant morbidity. Acute exacerbation of COPD (AECOPD) is a severe complication associated with increased short- and long-term mortality. Identifying predictors of long-term mortality after a severe AECOPD may improve management and long-term outcome of this disease. Materials and methods:A two-year prospective cohort study was undertaken in an academical medical center between 2016 and 2018. Patients with severe AECOPD who required non-invasive ventilation (NIV) were included. Baseline characteristics at inclusion, comorbidities (kidney dysfunction, left heart disease, diabetes), number of prior episodes of AECOPD and indication for long-term oxygen therapy (LTOT) or non-invasive ventilation (LTNIV) were recorded. Patients were monitored for a two-year period after initial admission. Outcomes were six-month, one-year and two-year mortality, irrespective of cause. Outcomes:51 patients (31 male, mean age 68.1) were included in the study. Mortality rates at six months, one year and two years were 20, 26 and 36%, respectively. Patients receiving LTOT and LTNIV at discharge had lower mortality at two years versus patients with no indication for LTOT and LTNIV at discharge. Absence of LTOT increased six-month mortality (OR .2, 95% CI, .04 to .90) and one-year mortality (p<.05). FEV1 and BMI were also correlated with long-term mortality in univariate analysis, p<.05. Age, number of prior episodes of AECOPD or the presence of comorbidities had no influence on long-term mortality. Conclusion:After an episode of severe AECOPD, LTOT is associated with lower long-term mortality when compared to patients with no severe hypoxemia at discharge. A decreased lung function and body mass index increase long-term mortality.

Clinical Guideline for Treating Acute Respiratory Insufficiency with Invasive Ventilation and Extracorporeal Membrane Oxygenation: Evidence-Based Recommendations for Choosing Modes and Setting Parameters of Mechanical Ventilation

For patients with acute respiratory insufficiency, mechanical ("invasive") ventilation is a fundamental therapeutic measure to ensure sufficient gas exchange. Despite decades of strong research efforts, central questions on mechanical ventilation therapy are still answered incompletely. Therefore, many different ventilation modes and settings have been used in daily clinical practice without scientifically sound bases. At the same time, implementation of the few evidence-based therapeutic concepts (e.g., "lung protective ventilation") into clinical practice is still insufficient. The aim of our guideline project "Mechanical ventilation and extracorporeal gas exchange in acute respiratory insufficiency" was to develop an evidence-based decision aid for treating patients with and on mechanical ventilation. It covers the whole pathway of invasively ventilated patients (including indications of mechanical ventilation, ventilator settings, additional and rescue therapies, and liberation from mechanical ventilation). To assess the quality of scientific evidence and subsequently derive recommendations, we applied the Grading of Recommendations, Assessment, Development and Evaluation method. For the first time, using this globally accepted methodological standard, our guideline contains recommendations on mechanical ventilation therapy not only for acute respiratory distress syndrome patients but also for all types of acute respiratory insufficiency. This review presents the two main chapters of the guideline on choosing the mode of mechanical ventilation and setting its parameters. The guideline group aimed that - by thorough implementation of the recommendations - critical care teams may further improve the quality of care for patients suffering from acute respiratory insufficiency. By identifying relevant gaps of scientific evidence, the guideline group intended to support the development of important research projects.

Beatmung bei COPD: von der Präklinik bis zur außerklinischen Beatmung. Eine Übersicht des Arbeitskreises für Beatmung und Intensivmedizin der österreichischen Gesellschaft für Pneumologie

This paper was created by the Austrian Society of Pneumology (Working group Ventilation and Intensive Care) to summarize the specific characteristics of mechanical ventilation in patients presenting with chronic obstructive pulmonary disease (COPD). The main differences in pathophysiology and mechanical ventilation are shown, including acute respiratory failure and out-of-hospital mechanical ventilation.

Reduction of PaCO2 by high-flow nasal cannula in acute hypercapnic respiratory failure patients receiving conventional oxygen therapy

Background:

It has been suggested that a high-flow nasal cannula (HFNC) could help to remove carbon dioxide (CO₂) from anatomical dead spaces, but evidence to support that is lacking. The objective of this study was to elucidate whether use of an HFNC could reduce the arterial partial pressure of CO₂ (PaCO₂) in patients with acute hypercapnic respiratory failure who are receiving conventional oxygen (O₂) therapy.

Methods:

A propensity score-matched observational study was conducted to evaluate patients treated with an HFNC for acute hypercapnic respiratory failure from 2015 to 2016. The hypercapnia group was defined as patients with a PaCO₂ >50 mm Hg and arterial pH <7.35.

Results:

Eighteen patients in the hypercapnia group and 177 patients in the nonhypercapnia group were eligible for the present study. Eighteen patients in each group were matched by propensity score. Decreased PaCO₂ and consequent pH normalization over time occurred in the hypercapnia group (P=0.002 and P=0.005, respectively). The initial PaCO₂ level correlated linearly with PaCO₂ removal after the use of an HFNC (R²=0.378, P=0.010). The fraction of inspired O₂ used in the intensive care unit was consistently higher for 48 hours in the nonhypercapnia group. Physiological parameters such as respiratory rate and arterial partial pressure of O₂ improved over time in both groups.

Conclusions:

Physiological parameters can improve after the use of an HFNC in patients with acute hypercapnic respiratory failure given low-flow O₂ therapy via a facial mask. Further studies are needed to identify which hypercapnic patients might benefit from an HFNC.

Acute Severe Asthma in Adolescent and Adult Patients: Current Perspectives on Assessment and Management

Asthma is a chronic airway inflammatory disease that is associated with variable expiratory flow, variable respiratory symptoms, and exacerbations which sometimes require hospitalization or may be fatal. It is not only patients with severe and poorly controlled asthma that are at risk for an acute severe exacerbation, but this has also been observed in patients with otherwise mild or moderate asthma. This review discusses current aspects on the pathogenesis and pathophysiology of acute severe asthma exacerbations and provides the current perspectives on the management of acute severe asthma attacks in the emergency department and the intensive care unit.

Mechanical Ventilation and Extracorporeal Membrane Oxygena tion in Acute Respiratory Insufficiency

BACKGROUND

Mechanical ventilation is life-saving for patients with acute respiratory insufficiency. In a German prevalence study, 13.6% of patients in intensive care units received mechanical ventilation for more than 12 hours; 20% of these patients received mechanical ventilation as treatment for acute respiratory distress syndrome (ARDS). The new S3 guideline is the first to contain recommendations for the entire process of treatment in these groups of patients (indications, ventilation modes/parameters, ac- companying measures, treatments for refractory impairment of gas exchange, weaning, and follow-up care).

METHODS

This guideline was developed according to the GRADE methods. Pertinent publications were identified by a systematic search of the literature, the quality of the evidence was evaluated, a risk/benefit assessment was conducted, and recommendations were issued by interdisciplinary consensus.

RESULTS

Mechanical ventilation is recommended as primary treatment for patients with severe ARDS. In other patient groups, non-in- vasive ventilation can lower mortality. If mechanical ventilation is needed, ventilation modes allowing spontaneous breathing seem beneficial (quality of evidence [QoE]: very low). Protective ventilation (high positive end-expiratory pressure, low tidal volume, limited peak pressure) improve the survival of ARDS patients (QoE: high). If a severe impairment of gas exchange is present, prone posi- tioning lessens mortality (QoE: high). Veno-venous extracorporeal membrane oxygenation (vvECMO) has not unequivocally been shown to improve survival. Early mobilization and weaning protocols can shorten the duration of ventilation (QoE: moderate).

CONCLUSION

Recommendations for patients undergoing mechanical ventilation include lung-protective ventilation, early sponta- neous breathing and mobilization, weaning protocols, and, for those with severe impairment of gas exchange, prone positioning. It is further recommended that patients with ARDS and refractory impairment of gas exchange should be transferred to an ARDS/ECMO center, where extracorporeal methods should be applied only after application of all other therapeutic options.

Predictors of outcome of noninvasive ventilation in severe COPD exacerbation

Background

Noninvasive ventilation (NIV) reduces the rate of endotracheal intubation (ETI) and overall mortality in severe acute exacerbation of COPD (AECOPD) with acute respiratory failure and is increasingly applied in respiratory intermediate care units. However, inadequate patient selection and incorrect management of NIV increase mortality. We aimed to identify factors that predict the outcome of NIV in AECOPD. Also, we looked for factors that influence ventilator settings and duration.

Methods

A prospective cohort study was undertaken in a respiratory intermediate care unit in an academic medical center between 2016 and 2017.

Age, BMI, lung function, arterial pH and pCO2 at admission (t0), at 1–2 h (t1) and 4–6 h (t2) after admission, creatinine clearance, echocardiographic data (that defined left heart dysfunction), mean inspiratory pressure during the first 72 h (mIPAP-72 h) and hours of NIV during the first 72 h (dNIV-72 h) were recorded.

Main outcome was NIV failure (i.e., ETI or in-hospital death). Secondary outcomes were in-hospital mortality, length of stay (LOS), duration of NIV (days), mIPAP-72 h, and dNIV-72 h.

Results

We included 89 patients (45 male, mean age 67.6 years) with AECOPD that required NIV. NIV failure was 12.4%, and in-hospital mortality was 11.2%. NIV failure was correlated with days of NIV, LOS, in-hospital mortality (p < 0.01), and kidney dysfunction (p < 0.05). In-hospital mortality was strongly associated with days of NIV (OR 1.27, 95%CI: 1.07–1.5, p < 0.01) and with FEV1 (p < 0.05). All other investigated parameters (including left heart dysfunction, dNIV-72 h, mIPAP-72 h, pH, etc.) did not influence NIV failure or mortality. dNIV-72 h and days of NIV were independent predictors of LOS (p < 0.01). Regarding the secondary outcomes, left heart dysfunction and pH at 1-2 h independently predicted NIV duration (dNIV-72 h, p < 0.01), while BMI and baseline pCO2 predicted NIV settings (mIPAP-72 h, p < 0.01).

Conclusion

In-hospital mortality and NIV failure were not influenced by BMI, left heart dysfunction, age, nor by arterial blood gas values in the first 6 h of NIV. Patients with severe acidosis and left heart dysfunction required prolonged use of NIV. BMI and pCO2 levels influence the NIV settings in AECOPD regardless of lung function.

Acute non-invasive ventilation - getting it right on the acute medical take

Non-invasive ventilation (NIV) given to the right patient, in the right setting, in the right way and at the right time improves outcomes. However, national audits reveal poor practice in patient selection, clinical judgement, treatment initiation and availability of trained staff. NIV is indicated for persistent acute hypercapnic respiratory failure (AHRF) with acidosis after usual medical management in chronic obstructive pulmonary disease (COPD) exacerbation and even without acidosis in neuromuscular disorders or other restrictive conditions eg obesity hypoventilation or kyphoscoliosis. Having trained staff in a suitable environment with adequate equipment are keys to its success, along with close monitoring. A plan should be put in place at the time of initiating NIV about the ceiling of care, eg escalation to intubation or palliation, if the patient is not improving with NIV. Early NIV failure is most likely due to technical issues, such as inadequate pressures or mask leak, while late failure is usually the consequence of advanced disease. Any presentation with AHRF is a poor prognostic indicator and outpatient respiratory follow-up is indicated following discharge. For selected patients with COPD who remain hypercapnic 2 weeks after an exacerbation, domiciliary NIV can reduce admissions and improve survival. For patients with neuromuscular disorders or kyphoscoliosis a presentation with AHRF almost always indicates the need for domiciliary NIV.

Late presentation of acute hypercapnic respiratory failure carries a high mortality risk in COPD patients treated with ward-based NIV

INTRODUCTION

Non-invasive ventilation (NIV) is recommended for treatment of acute hypercapnic respiratory failure (AHRF) refractory to medical management in patients with COPD. This study investigated the relationship between time from hospital presentation to diagnosis of AHRF and in-hospital mortality.

METHODS

Retrospective analysis of hospitalised COPD patients treated with a first episode of ward-based NIV for AHRF at a large UK teaching hospital between 2004 and 2017. Data collected prospectively as part of NIV service evaluation. Multivariable logistic regression performed to identify predictors of in-hospital mortality.

RESULTS

In total, 547 unique patients were studied comprising 245 males (44.8%), median age 70.6 years, median FEV1% predicted 34%. Overall in-hospital mortality was 19% (n = 104); median survival was 1.7 years. In univariate analysis, a longer time between hospital presentation to diagnosis of AHRF was associated with in-hospital mortality (median [IQR]: 8.7 [0.7-75.8] hours vs. 1.9 [0.3-13.6] hours, p < 0.0001). In multivariable logistic regression, significant predictors of in-hospital mortality were AHRF >24 h after hospital presentation (odds ratio [95% CI]: 2.29 [1.33-3.95], p = 0.003), pneumonia on admission (1.81 [1.07-3.08], p = 0.027), increased age (1.10 [1.07-1.14], p < 0.001) and NIV as ceiling of treatment (5.86 [2.87-11.94], p < 0.001).

CONCLUSIONS

Hospitalised COPD patients with late presentation of AHRF, requiring acute ward-based NIV, may have increased in-hospital mortality. These patients may benefit from closer monitoring and earlier specialist respiratory review.

Calculated arterial blood gas values from a venous sample and pulse oximetry: Clinical validation

Background

Arterial blood gases (ABG) are essential for assessment of patients with severe illness, but sampling is difficult in some settings and more painful than for peripheral venous blood gas (VBG). Venous to Arterial Conversion (v-TAC; OBIMedical ApS, Denmark) is a method to calculate ABG values from a VBG and pulse oximetry (SpO₂). The aim was to validate v-TAC against ABG for measuring pH, carbon dioxide (pCO₂) and oxygenation (pO₂).

Methods

Of 103 sample sets, 87 paired ABGs and VBGs with SpO₂ from 46 inpatients eligible for ABG met strict sampling criteria. Agreement was evaluated using mean difference with 95% limits of agreement (LoA) and Bland-Altman plots.

Results

v-TAC had very high agreement with ABG for pH (mean diff_{(ABG–v-TAC)} -0.001; 95% LoA -0.017 to 0.016), pCO₂ (-0.14 kPa; 95% LoA -0.46 to 0.19) and moderate to high for pO₂ (-0.28 kPa; 95% LoA -1.31 to 0.76). For detecting hypercapnia (PaCO₂>6.0 kPa), v-TAC had sensitivity 100%, specificity 93.8% and accuracy 97%. The accuracy of v-TAC for detecting hypoxemia (PaO₂<8.0 kPa) was comparable to that of pulse oximetry. Agreement with ABG was higher for v-TAC than for VBG for all analyses.

Conclusion

Calculated arterial blood gases (v-TAC) from a venous sample and pulse oximetry were comparable to ABG values and may be useful for evaluation of blood gases in clinical settings. This could reduce the logistic burden of arterial sampling, facilitate improved screening and follow-up and reduce patient pain.

Obesity hypoventilation syndrome

Obesity hypoventilation syndrome (OHS) is defined as a combination of obesity (body mass index ≥30 kg·m-2), daytime hypercapnia (arterial carbon dioxide tension ≥45 mmHg) and sleep disordered breathing, after ruling out other disorders that may cause alveolar hypoventilation. OHS prevalence has been estimated to be ∼0.4% of the adult population. OHS is typically diagnosed during an episode of acute-on-chronic hypercapnic respiratory failure or when symptoms lead to pulmonary or sleep consultation in stable conditions. The diagnosis is firmly established after arterial blood gases and a sleep study. The presence of daytime hypercapnia is explained by several co-existing mechanisms such as obesity-related changes in the respiratory system, alterations in respiratory drive and breathing abnormalities during sleep. The most frequent comorbidities are metabolic and cardiovascular, mainly heart failure, coronary disease and pulmonary hypertension. Both continuous positive airway pressure (CPAP) and noninvasive ventilation (NIV) improve clinical symptoms, quality of life, gas exchange, and sleep disordered breathing. CPAP is considered the first-line treatment modality for OHS phenotype with concomitant severe obstructive sleep apnoea, whereas NIV is preferred in the minority of OHS patients with hypoventilation during sleep with no or milder forms of obstructive sleep apnoea (approximately <30% of OHS patients). Acute-on-chronic hypercapnic respiratory failure is habitually treated with NIV. Appropriate management of comorbidities including medications and rehabilitation programmes are key issues for improving prognosis.

Noninvasive Ventilation Weaning in Acute Hypercapnic Respiratory Failure due to COPD Exacerbation: A Real-Life Observational Study

The most recent British Thoracic Society/Intensive Care Society (BTS/ICS) guidelines on the use of noninvasive ventilation (NIV) in acute hypercapnic respiratory failure (AHRF) suggest to maximize NIV use in the first 24 hours and to perform a slow tapering. However, a limited number of studies evaluated the phase of NIV weaning. The aim of this study is to describe the NIV weaning protocol used in AHRF due to acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), patients' characteristics, clinical course, and outcomes in a real-life intermediate respiratory care unit (IRCU) setting. We performed a retrospective study on adult patients hospitalized at the IRCU of San Gerardo Hospital, Monza, Italy, from January 2015 to April 2017 with a diagnosis of AHRF due to COPD exacerbation. The NIV weaning protocol used in our institution consists of the interruption of one of the three daily NIV sessions at the time, starting from the morning session and finishing with the night session. The 51 patients who started weaning were divided into three groups: 20 (39%) patients (median age 80 yrs, 65% males) who completed the protocol and were discharged home without NIV (Completed Group), 20 (39%) did not complete it because they were adapted to domiciliary ventilation (Chronic NIV Group), and 11 (22%) interrupted weaning ex abrupto mainly due to NIV intolerance (Failed Group). Completed Group patients were older, had a higher burden of comorbidities, but a lower severity of COPD compared to Chronic NIV Group. Failed Group patients experienced higher frequency of delirium after NIV discontinuation. None of the patients who completed weaning had AHRF relapse during hospitalization. While other NIV weaning methods have been previously described, our study is the first to describe a protocol that implies the interruption of a ventilation session at the time. The application of a weaning protocol may prevent AHRF relapse in the early stages of NIV interruption and in elderly frail patients.

Temporal trends in survival following ward-based NIV for acute hypercapnic respiratory failure in patients with COPD

INTRODUCTION

Non-invasive ventilation (NIV) is recommended for treatment of acute hypercapnic respiratory failure (AHRF) in acute exacerbations of COPD. National UK audit data suggests that mortality rates are rising in COPD patients treated with NIV.

OBJECTIVE

To investigate temporal trends in in-hospital mortality in COPD patients undergoing a first episode of ward-based NIV for AHRF.

METHODS

Retrospective study of hospitalised COPD patients treated with a first episode of ward-based NIV at a large UK teaching hospital between 2004 and 2017. Patients were split into two cohorts based on year of admission, 2004-2010 (Cohort 1) and 2013-2017 (Cohort 2), to facilitate comparison of patient characteristics.

RESULTS

In total, 547 unique patients were studied. There was no difference in in-hospital mortality rate between the time periods studied (17.6% vs 20.5%, P = .378). In Cohort 2 there were more females, a higher rate of co-morbid bronchiectasis and pneumonia on admission and more severe acidosis, hypercapnia and hypoxia. More patients in Cohort 2 had NIV as the ceiling of treatment. Patients in Cohort 2 experienced a longer time from AHRF diagnosis to application of NIV, higher maximum inspiratory positive airway pressure, lower maximum oxygen and shorter duration of NIV. Finally, patients in Cohort 2 experienced a shorter hospital length of stay (LOS), with no differences observed in rate of transfer to critical care or intubation.

CONCLUSION

In-hospital mortality remained stable and LOS decreased over time, despite greater comorbidity and more severe AHRF in COPD patients treated for the first time with ward-based NIV.

Non-invasive ventilation in acute respiratory failure of patients with obesity hypoventilation syndrome

INTRODUCTION

Non-invasive ventilation (NIV) has been used successfully for the management of acute respiratory failure (ARF) more often in the last two decades compared to prior decades. There are particular groups of patients that are more likely to benefit from NIV. One of these groups is patients with obesity hypoventilation syndrome (OHS). The aim of this review is to evalue the effectiveness of NIV in acute ARF.

EVIDENCE ACQUISITION

MEDLINE, EMBASE, CINHAIL, Cochrane Central Register of Controlled Trials, DARE, the Cochrane Database of Systematic Reviews, and the ACP Journal Club database were searched from January 2001 to December 2017.

EVIDENCE SYNTHESIS

More than 30% of them have been diagnosed when hospitalized for ARF. NIV rarely failed in reversing ARF. OHS patients who exhibited early NIV failure had a high severity score and a low HCO3 level at admission; more than half of hypercapnic patients with decompensated OHS exhibited a delayed but successful response to NIV.

CONCLUSIONS

Patients with decompensation of OHS have a better prognosis and response to NIV than other hypercapnic patients. They required more aggressive NIV settings, a longer time to reduce paCO2 levels, and showed more frequently a delayed but successful response to NIV.

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.

Ward-Based Non-Invasive Ventilation in Acute Exacerbations of COPD: A Narrative Review of Current Practice and Outcomes in the UK

Non-invasive ventilation (NIV) is frequently used as a treatment for acute hypercapnic respiratory failure (AHRF) in hospitalised patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). In the UK, many patients with AHRF secondary to AECOPD are treated with ward-based NIV, rather than being treated in critical care. NIV has been increasingly used as an alternative to invasive ventilation and as a ceiling of treatment in patients with a ‘do not intubate’ order. This narrative review describes the evidence base for ward-based NIV in the context of AECOPD and summarises current practice and clinical outcomes in the UK.

Non-invasive ventilation: Essential requirements and clinical skills for successful practice

Audits and case reviews of the acute delivery of non-invasive ventilation (NIV) have shown that the results achieved in real life often fall short of those achieved in research trials. Factors include inappropriate selection of patients for NIV and failure to apply NIV correctly. This highlights the need for proper training of all involved individuals. This article addresses the different skills needed in a team to provide an effective NIV service. Some detail is given in each of the key areas but it is not comprehensive and should stimulate further learning (reading, attendance on courses, e-learning, etc.), determined by the needs of the individual.

Effect of Protocolized Weaning With Early Extubation to Noninvasive Ventilation vs Invasive Weaning on Time to Liberation From Mechanical Ventilation Among Patients With Respiratory Failure: The Breathe Randomized Clinical Trial

IMPORTANCE

In adults in whom weaning from invasive mechanical ventilation is difficult, noninvasive ventilation may facilitate early liberation, but there is uncertainty about its effectiveness in a general intensive care patient population.

OBJECTIVE

To investigate among patients with difficulty weaning the effects of protocolized weaning with early extubation to noninvasive ventilation on time to liberation from ventilation compared with protocolized invasive weaning.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, allocation-concealed, open-label, multicenter clinical trial enrolling patients between March 2013 and October 2016 from 41 intensive care units in the UK National Health Service. Follow-up continued until April 2017. Adults who received invasive mechanical ventilation for more than 48 hours and in whom a spontaneous breathing trial failed were enrolled.

INTERVENTIONS

Patients were randomized to receive either protocolized weaning via early extubation to noninvasive ventilation (n = 182) or protocolized standard weaning (continued invasive ventilation until successful spontaneous breathing trial, followed by extubation) (n = 182).

MAIN OUTCOMES AND MEASURES

Primary outcome was time from randomization to successful liberation from all forms of mechanical ventilation among survivors, measured in days, with the minimal clinically important difference defined as 1 day. Secondary outcomes were duration of invasive and total ventilation (days), reintubation or tracheostomy rates, and survival.

RESULTS

Among 364 randomized patients (mean age, 63.1 [SD, 14.8] years; 50.5% male), 319 were evaluable for the primary effectiveness outcome (41 died before liberation, 2 withdrew, and 2 were discharged with ongoing ventilation). The median time to liberation was 4.3 days in the noninvasive group vs 4.5 days in the invasive group (adjusted hazard ratio, 1.1; 95% CI, 0.89-1.40). Competing risk analysis accounting for deaths had a similar result (adjusted hazard ratio, 1.1; 95% CI, 0.86-1.34). The noninvasive group received less invasive ventilation (median, 1 day vs 4 days; incidence rate ratio, 0.6; 95% CI, 0.47-0.87) and fewer total ventilator days (median, 3 days vs 4 days; incidence rate ratio, 0.8; 95% CI, 0.62-1.0). There was no significant difference in reintubation, tracheostomy rates, or survival. Adverse events occurred in 45 patients (24.7%) in the noninvasive group compared with 47 (25.8%) in the invasive group.

CONCLUSIONS AND RELEVANCE

Among patients requiring mechanical ventilation in whom a spontaneous breathing trial had failed, early extubation to noninvasive ventilation did not shorten time to liberation from any ventilation.

TRIAL REGISTRATION

ISRCTN Identifier: ISRCTN15635197.

Obstructive sleep apnea in patients surviving acute hypercapnic respiratory failure is best predicted by static hyperinflation

Rationale

Acute hypercapnic respiratory failure (AHRF) treated with non-invasive ventilation in the ICU is frequently caused by chronic obstructive pulmonary disease (COPD) exacerbations and obesity-hypoventilation syndrome, the latter being most often associated with obstructive sleep apnea. Overlap syndrome (a combination of COPD and obstructive sleep apnea) may represent a major burden in this population, and specific diagnostic pathways are needed to improve its detection early after ICU discharge.

Objectives

To evaluate whether pulmonary function tests can identify a high probability of obstructive sleep apnea in AHRF survivors and outperform common screening questionnaires to identify the disorder.

Methods

Fifty-three patients surviving AHRF (31 males; median age 67 years (interquartile range: 62–74) participated in the study. Anthropometric data were recorded and body plethysmography was performed 15 days after ICU discharge. A sleep study was performed 3 months after ICU discharge.

Results

The apnea-hypopnea index was negatively associated with static hyperinflation as measured by the residual volume to total lung capacity ratio in the % of predicted (coefficient = -0.64; standard error 0.17; 95% CI -0.97 to -0.31; p<0.001). A similar association was observed in COPD patients only: coefficient = -0.65; standard error 0.19; 95% CI -1.03 to -0.26; p = 0.002. Multivariate analysis with penalized maximum likelihood confirmed that the residual volume to total lung capacity ratio was the main contributor for apnea-hypopnea index variance in addition to classic predictors. Screening questionnaires to select patients at risk for sleep-disordered breathing did not perform well.

Conclusions

In AHRF survivors, static hyperinflation is negatively associated with the apnea-hypopnea index in both COPD and non-COPD patients. Measuring static hyperinflation in addition to classic predictors may help to increase the recognition of obstructive sleep apnea as common screening tools are of limited value in this specific population.

Comparison of high flow nasal cannula oxygen and conventional oxygen therapy on ventilatory support duration during acute-on-chronic respiratory failure: study protocol of a multicentre, randomised, controlled trial. The 'HIGH-FLOW ACRF' study

INTRODUCTION

This study protocol describes a trial designed to investigate whether high-flow heated and humidified nasal oxygen (HFHO) therapy in patients with hypercapnic acute respiratory failure (ARF) reduces the need of non-invasive ventilation (NIV).

METHODS AND ANALYSIS

This is an open-label, superiority, international, parallel-group, multicentre randomised controlled two-arm trial, with an internal feasibility pilot phase. 242 patients with hypercapnic ARF requiring NIV admitted to an intensive care unit, an intermediate care or a respiratory care unit will be randomised in a 1:1 ratio to receive HFHO or standard oxygen in between NIV sessions. Randomisation will be centralised and stratified by centre and pH at admission (pH ≤7.25 or >7.25). The primary outcome will be the number of ventilator-free days (VFDs) and alive at day 28 postrandomisation. The secondary outcomes will encompass parameters related to the VFDs, comfort and tolerance variables, hospital length of stay and mortality. VFDs at 28 days postrandomisation will be compared between the two groups by Wilcoxon-Mann-Whitney two-sample rank-sum test in the intention-to-treat population. A sensitivity analysis will be conducted in the population of patients for whom the criteria of switching from NIV to spontaneous breathing, or conversely, are not strictly verified.

ETHICS AND DISSEMINATION

The protocol has been approved by the Comité de Protection des Personnes (CPP) Sud-Ouest & Outre-Mer IV (ref CPP17-049a/2017-A01830-53) and will be carried out in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. A trial steering committee will oversee the progress of the study. Findings will be disseminated through national and international scientific conferences, and publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03406572.

Complications and Pharmacologic Interventions of Invasive Positive Pressure Ventilation During Critical Illness

Objective: To review the fundamentals of invasive positive pressure ventilation (IPPV) and the common complications and associated pharmacotherapeutic management in order to provide opportunities for pharmacists to improve patient outcomes. Data Sources: A MEDLINE literature search (1950-December 2017) was performed using the key search terms invasive positive pressure ventilation, mechanical ventilation, pharmacist, respiratory failure, ventilator associated organ dysfunction, ventilator associated pneumonia, ventilator bundles, and ventilator liberation. Additional references were identified from a review of literature citations. Study Selection and Data Extraction: All English-language original research and review reports were evaluated. Data Synthesis: IPPV is a common supportive care measure for critically ill patients. While lifesaving, IPPV is associated with significant complications including ventilator-associated pneumonia, sinusitis, organ dysfunction, and hemodynamic alterations. Optimization of pain and sedation management provides an opportunity for pharmacists to directly affect IPPV exposure. A number of pharmacotherapeutic interventions are related directly to prophylaxis against IPPV-associated adverse events or aimed at reduction of duration of IPPV. Conclusions: Enhanced knowledge of the common complications, associated pharmacotherapy, and monitoring strategies facilitate the pharmacist's ability to provide increased pharmacotherapeutic insight in a multidisciplinary intensive care unit setting.

Mortality in acute non-invasive ventilation

A prospective study of non-invasive ventilation at The Prince Charles Hospital outside of the intensive care unit from March 2015 to March 2016 was performed. Overall 69 patients were included. Acute hypercapnic respiratory failure was the most common indication (n = 59; 85%). 49 (71%) had multifactorial respiratory failure. 15 (22%) patients died. Premorbid inability to perform self-care (P = 0.001) and the combination of mean pH < 7.25 and mean PaCO₂ ≥ 75 mmHg within 2 h of NIV initiation (P = 0.037) were significantly associated with mortality. There was a non-significant association between older age and mortality.