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

Ventilators, Settings, Autotitration Algorithms

The choice of a ventilator model for a single patient is usually based on parameters such as size (portability), presence or absence of battery and ventilatory modes. However, there are many details within each ventilator model about triggering, pressurisation or autotitration algorithms that may go unnoticed, but may be important or may justify some drawbacks that may occur during their use in individual patients. This review is intended to emphasize these differences. Guidance is also provided on the operation of autotitration algorithms, in which the ventilator is able to take decisions based on a measured or estimated parameter. It is important to know how they work and their potential sources of error. Current evidence on their use is also provided.

Noninvasive positive pressure in acute exacerbations of chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Noninvasive positive pressure ventilation (NIV) is standard of care for patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD). We review the most current evidence and highlight areas of uncertainty and ongoing research. We highlight key concepts for the clinician caring for patients with AECOPD which require NIV.

RECENT FINDINGS

Implementation of NIV in AECOPD is not uniform in spite of the evidence and guidelines. Initiation of NIV should be done early and following protocols. Low-intensity NIV remains the standard of care, although research and guidelines are evaluating higher intensity NIV. Scores to predict NIV failure continue to be refined to allow early identification and interventions. Several areas of uncertainty remain, among them are interventions to improve tolerance, length of support and titration and nutritional support during NIV.

SUMMARY

The use of NIV in AECOPD is the standard of care as it has demonstrated benefits in several patient-centered outcomes. Current developments and research is related to the implementation and adjustment of NIV.

Role of Average Volume Assured Pressure Support Mode (AVAPS) in the Management of Acute Exacerbation of Chronic Obstructive Pulmonary Disease With Type 2 Respiratory Failure

Background Non-invasive ventilation (NIV) is a well-established approach in the treatment of acute exacerbation of chronic obstructive pulmonary disease (COPD) with type 2 respiratory failure. Average volume-assured pressure support (AVAPS) mode integrates the characteristics of both volume and pressure-controlled modes of NIV. In bilevel positive airway pressure (BiPAP) mode, volume is the dependent variable, whereas in AVAPS mode, pressure is the dependent variable. In this study, we aimed to compare the role of AVAPS mode with BiPAP spontaneous/timed (S/T) mode for the management of patients with acute exacerbation of COPD with type 2 respiratory failure. Methodology A hospital-based comparative and analytical study was carried out on 100 patients with acute exacerbation of COPD with type 2 respiratory failure admitted to respiratory disease hospital, Sardar Patel Medical College, Bikaner (Rajasthan, India). Patients were randomly divided into two groups of 50 patients each. Group A patients were treated with AVAPS mode and group B patients with BiPAP (S/T) mode. Arterial blood gases, average duration of hospital stay, and need for invasive mechanical ventilation were compared between the two groups. Results There was a statistically significant difference in favor of group A in terms of improvement in pH and pCO2 as compared to group B at 6 h (pH, p=0.027; pCO2, p=0.012) and 24 h (pH, p=0.032; pCO2, p=0.013). The duration of hospital stay was found to be lower in group A (p=0.003). However, no significant difference was found in terms of need for invasive mechanical ventilation between both groups (p=0.338). Conclusion Application of AVAPS mode results in more rapid and steady improvement in patients of COPD as compared to BiPAP (S/T) mode. Thus, management through non-invasive ventilation AVAPS mode should be considered in patients with acute exacerbation of COPD with type 2 respiratory failure.

Comparison of Volume Support, Volume-Assured Pressure Support, and Spontaneous Modes in Postoperative Early Extubated Patients

Background

This study aimed to compare respiratorily, arterial blood gas (ABG), and hemodynamics parameters among patients undergoing surgery who were admitted to intensive care unit (ICU), using three ventilation modes, including volume-assured pressure support (VAPS), volume support (VS), and spontaneous modes.

Materials and Methods

One hundred and thirty-two patients were randomly assigned into three groups of VAPS, VS, and spontaneous modes utilizing randomized block procedure. Patients were followed between 12 and 30 h until extubation. Respiratory parameters including; peak inspiratory pressure (PIP), static compliance, resistance, rapid shallow breathing index (RSBI), and P 0.1(P0.1 correlates with respiratory drive and is defined as the negative pressure measured at the airway opening 100 ms after the initiation of an inspiratory effort), along with ABG parameters including; pH level, PaCO₂,HCO₃,PaO₂/FiO₂ ratio, extra hydrogen ion, and hemodynamics parameters including; mean arterial blood pressure and heart rate were measured every 3 h and compared among groups.

Results

All studied parameters in three groups improved during the study. PIP, Resistance, PH, HCO₃, extra hydrogen ion, PCo₂, PaO₂/FiO₂ ratio, mean arterial blood pressure were similar among the three groups in most of the time points (P > 0.05). In most of the time points, RSBI (from 92.7 to 55.4), P 0.1 (from 6.8 to 1.7) in the VAPS group, static compliance (from 55.3 to 55.7) in the VS group, and heart rate (from 108.5 to 90.1) in spontaneous groups were significantly better than other modes (P < 0.05). Changes in RSBI, P 0.1, PCo₂, HCO₃, and heart rate during the study were significantly different among studied groups (P < 0.05). The length of stay in the ICU in patients who underwent VAPS was significantly shorter than the other modes.

Conclusions

VAPS mode with better effects or at least as effective as VS and spontaneous modes could be select as the best mode of ventilation in postoperative early extubated patients admitted to ICU.

Noninvasive Mechanical Ventilation with Average Volume-Assured Pressure Support versus BiPAP S/T in De Novo Hypoxemic Respiratory Failure

Background

Bilevel positive airway pressure in spontaneous/time and average volume-assured pressure support (BiPAP·S/T-AVAPS) could maintain an adequate tidal volume by reducing the patient's inspiratory effort; however, this ventilatory strategy has not been compared with other ventilatory modes, especially the conventional BiPAP S/T mode, when noninvasive mechanical ventilation (NIMV) is used. The primary objective of this study was to determine the rate of success and failure of the use of BiPAP·S/T-AVAPS versus BiPAP·S/T alone in patients with mild-to-moderate "de novo" hypoxemic respiratory failure.

Methods

This was a matched-cohort study. Subjects with mild-to-moderate de novo hypoxemic respiratory failure were divided into two groups according to the ventilatory strategy used. The subjects in the BiPAP·S/T group were paired with those in the BiPAP·S/T-AVAPS group.

Results

A total of 58 subjects were studied. Twenty-nine subjects in the BiPAP·S/T group were paired with 29 subjects in the BiPAP·S/T-AVAPS group. Twenty patients (34.5%) presented with "failure of NIMV," while 38 (65.5%) patients did not. In addition, 13 (22.4%) patients died, while 45 (77.6%) recovered. No differences were found in the percentage of intubation (P=0.44) and mortality (P=0.1).

Conclusion

The BiPAP S/T-AVAPS ventilator mode was not superior to the BiPAP·S/T mode. A high mortality rate was observed in patients with NIMV failure in both modes. This trial is registered with https://doi.org/10.1186/ISRCTN17904857.

PAP therapy and readmission rates after in-hospital laboratory titration polysomnography in patients with hypoventilation

STUDY OBJECTIVES

Hypoventilation associated with sleep disordered breathing in inpatients is associated with higher risk of morbidity, hospitalizations and death. In-hospital titration polysomnography qualifies patients for positive airway pressure (PAP) therapy and optimizes settings, but impact is unknown. This study describes a process for in-hospital sleep testing and evaluates subsequent PAP adherence and readmission.

METHODS

A retrospective cohort of patients with hypoventilation and in-hospital titration polysomnography with available PAP data were analyzed to determine whether PAP adherence was associated with 90-day readmission. Absolute differences were obtained using logistic regression models. Models were adjusted for body mass index, age and Elixhauser Index. PAP adherence and nonadherence were defined as ≥ 4 and < 4 hours daily average use prior to readmission or first 90-days post-discharge.

RESULTS

81 patients, 50.6% male, age (mean ± SD) 61.1 ± 13.5 years were included. Comorbid sleep disorders included 91.4% with OSA and 23.5% with central sleep apnea. 28/52 (53.8%) nonadherent and 6/29 (20.7%) adherent patients had 90-day readmissions. 11 (13.6%) patients (all nonadherent) were readmitted within 2 weeks of discharge. Adjusted model showed a 35.6% (95% CI 15.9%-55.2%) reduction in 90-day readmission in adherent group compared to nonadherent (p=0.004). Similar reductions in readmission were found with adherence ≥ 50% and ≥ 70% days ≥ 4 hours. Male sex, treatment with iVAPS, and highest CO₂ ≥ 60 mmHg on polysomnography were associated with largest differences in readmission rates between adherent and nonadherent patients.

CONCLUSIONS

Adherence to optimized PAP therapy after in-hospital titration polysomnography in patients with hypoventilation may decrease readmissions.

APAP, BPAP, CPAP, and New Modes of Positive Airway Pressure Therapy

Positive airway pressure (PAP) is the primary treatment of sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. Just as clinicians use pharmacological mechanism of action and pharmacokinetic data to optimize medication therapy for an individual, understanding how PAP works and choosing the right mode and device are critical to optimizing therapy in an individual patient. The first section of this chapter will describe the technology inside PAP devices that is essential for understanding the algorithms used to control the airflow and pressure. The second section will review how different comfort settings including ramp and expiratory pressure relief and modes of PAP therapy including continuous positive airway pressure (CPAP), autotitrating CPAP, bilevel positive airway pressure, adaptive servoventilation, and volume-assured pressure support control the airflow and pressure. Proprietary algorithms from several different manufacturers are described. This chapter derives its descriptions of algorithms from multiple sources including literature review, manufacture publications and websites, patents, and peer-reviewed device comparisons and from personal communication with manufacturer representatives. Clinical considerations related to the technological aspects of the different algorithms and features will be reviewed.

Apnea-Hypopnea Index in Chronic Obstructive Pulmonary Disease Exacerbation Requiring Noninvasive Mechanical Ventilation with Average Volume-Assured Pressure Support

Introduction

This study intends to determine the Apnea-Hypopnea Index in patients hospitalized with acute hypercapnic respiratory failure from chronic obstructive pulmonary disease exacerbation, who require noninvasive ventilation with average volume-assured pressure support (AVAPS), as well as describes the clinical characteristics of these patients.

Materials and Methods

We designed a single-center prospective study. The coexistence of Apnea-Hypopnea Index and clinical, gasometric, spirometric, respiratory polygraphy, and ventilatory characteristics were determined. The clinical characteristics found were categorized and compared according to the Apnea-Hypopnea Index (AHI) < 5, AHI 5–15, and AHI >15. A p value <0.05 was considered statistically significant.

Results

During the study period, a total of 100 patients were admitted to the ICU with a diagnosis of acute hypercapnic respiratory failure due to COPD exacerbation. 72 patients presented with acute respiratory failure and fulfilled criteria for ventilatory support. Within them, 24 received invasive mechanical ventilation and 48 NIV. After applying the inclusion criteria for this study, 30 patients were eligible. An AHI >5 was present in 24 of the 30 patients recruited (80%). Neck circumference (cm), Epworth scale, and Mallampati score evidenced significant differences when compared to the patient's AHI <5, AHI 5–15, and AHI >15 (p < 0.05). Furthermore, patients with an AHI >5 had longer hospital admissions, prolonged periods on mechanical ventilation, and a higher percentage of intubation rates.

Conclusion

Apnea-Hypopnea Index and chronic obstructive pulmonary disease exacerbation are a frequent association found in patients with acute hypercapnic respiratory failure and COPD exacerbations that require NIV. This association could be a determining factor in the response to NIV, especially when AVAPS is used as a ventilatory strategy.

Case report: fast reversal of malignant obesity hypoventilation syndrome after noninvasive ventilation and pulmonary rehabilitation

Background

Malignant obesity hypoventilation syndrome (MOHS) is described as a subtype condition of OHS, characterized by extreme obesity, obese-related hypoventilation, and multiorgan dysfunction. Because of low awareness and inadequate treatment, MOHS leads to high morbidity and mortality.

Case presentation

A 53-year-old man was diagnosed with MOHS evidenced by extreme obesity and multiorgan abnormalities. After taken noninvasive ventilation (NIV) treatment, he was rescued. And at the end of the six-month pulmonary rehabilitation (PR) program, improvement in terms of respiratory parameters, BMI, apnea-hypopnea index (AHI), and pulmonary hypertension were observed in the patient. Two years later, the patient was still in good condition.

Conclusions

This case highlights the awareness and proper use of NIV to rescue MOHS patients. Furthermore, the benefits of PR were explored in this case, which has not been considered within the therapeutic options for MOHS patients.

Treatment of critically ill patients with acute hypercarbic respiratory failure by average volume-assured pressure support mode

OBJECTIVES

Average volume-assured pressure support (AVAPS), a dual mode, delivers a set tidal volume (TV) per kg by adjusting the pressure between upper and lower inspiratory positive airway pressures (IPAP). Thus, ventilation is presumed to be happened effectively by sending a guaranteed TV. This study was aimed to evaluate the effectiveness of AVAPS mode in critically ill patients with acute hypercarbic respiratory failure (HRF) and compare the results with bilevel positive airway pressure-spontaneous/timed (BPAP-S/T) mode.

METHODS

Sixty patients were assigned to BPAP-S/T (n = 29) and AVAPS modes (n = 31). Maximum IPAP was started at 20 cmH₂ O and minimum IPAP was set at 5 cmH₂ O higher than expiratory positive airway pressure (EPAP) in AVAPS mode. IPAP was started at 15 cmH₂ O in BPAP-S/T mode. IPAP levels were titrated up to 30 cmH₂ O during noninvasive mechanic ventilation (NIMV) with a targeted TV of 6-8 mL/kg. Patients were followed for 5 days.

RESULTS

No differences were found in pH, paCO₂ , HCO₃ , TV and EPAP between the two groups when compared separately by days. Maximum IPAP levels were significantly high in AVAPS mode in all times (P < 0.001). The length of stay (LOS) in intensive care unit (ICU) (P = 0.994) and hospital (P = 0.509), hours of NIMV use per day (P = 0.101) and NIMV success rate (P = 0.931) were identical between the two groups. ICU (P = 0.931), hospital (P = 0.800), 6-month (P = 0.919) and 1-year (P = 0.645) mortality rates were also not different between the both groups.

CONCLUSIONS

AVAPS mode had similar efficiency with BPAP-S/T mode regarding the NIMV treatment success in critically ill patients with acute HRF.

Average volume-assured pressure support vs conventional bilevel pressure support in pediatric nocturnal hypoventilation: a case series

STUDY OBJECTIVES

Average volume-assured pressure support (AVAPS) is a modality of noninvasive ventilation that provides a targeted tidal volume by automatically adjusting the inspiratory pressure support within a set range. Pediatric studies evaluating the efficacy of AVAPS in treating nocturnal hypoventilation are confined to case reports. The aim of this study was to compare AVAPS to conventional bilevel positive airway pressure (BPAP) support in improving hypercarbia in a cohort of pediatric patients with nocturnal hypoventilation.

METHODS

Retrospective review of patient records at an established tertiary pediatric sleep laboratory over a 6-year period. Ventilatory and sleep study parameters from AVAPS and conventional BPAP titration studies were compared. AVAPS was used only if hypoventilation was not controlled using conventional BPAP. Inspiratory pressures, tidal volumes, and adherence were downloaded on final titrated ventilatory settings. Comparisons were made using paired t test.

RESULTS

A total of 19 patients (11 boys, 8 girls; median age 10.5 years, range 1 to 20 years) were identified. Diagnoses included neuromuscular disease (n = 9), obstructive hypoventilation (n = 5), parenchymal lung disease (n = 4), and congenital central hypoventilation syndrome (n = 2). AVAPS demonstrated significant improvement in peak (P = .009) and mean (P = .001). Transcutaneous CO₂ parameters compared to conventional bilevel. Oxygenation on AVAPS showed positive trend but did not reach statistical significance. AVAPS delivered higher tidal volumes (P = .04) using similar pressures. There was no statistically significant difference in obstructive apnea-hypopnea index, respiratory arousal index, sleep efficiency, and adherence between AVAPS and conventional BPAP.

CONCLUSIONS

AVAPS was an effective alternative to conventional BPAP in improving hypercarbia in our selective cohort of pediatric patients. Prospective, longitudinal studies are needed to evaluate the benefits of AVAPS feature in the pediatric population.

Use of the modified Glasgow Coma Scale score to guide sequential invasive-noninvasive mechanical ventilation weaning in patients with AECOPD and respiratory failure

Sequential invasive-noninvasive ventilation (NIV) improves the outcomes of patients with respiratory failure caused by acute exacerbation of chronic obstructive pulmonary disease (AECOPD); however, there is no clear consensus on the optimal timing of the switch to sequential invasive-NIV in these patients. In the present study, a potential role for the modified Glasgow Coma Scale (GCS) score to guide sequential weaning was investigated. Patients with AECOPD and respiratory failure were prospectively recruited from three study centers (Wenling Hospital Affiliated to Wenzhou Medical University, the First Affiliated Hospital of Wenzhou Medical University and Changsha Central Hospital) between January 1st 2016 and December 31st 2018. Patients were randomly assigned to group A and B, with the switching point for sequential weaning strategy in the two groups being a modified GCS score ≥13 and 10 points, respectively. Each group included 240 patients. Baseline demographic characteristics were comparable in the two groups. The duration of invasive mechanical ventilation (IMV) in group A was significantly shorter than that in group B. However, there were no significant between-group differences with respect to the incidence of re-intubation, ventilator-associated pneumonia, in-hospital mortality or the length of hospital stay. Use of a modified GCS score ≥13 as the switching point for sequential invasive-NIV may help decrease the duration of IMV in patients with AECOPD and respiratory failure.

Effects of volume-assured pressure support noninvasive ventilation in stable COPD with chronic respiratory failure: Meta-analysis and literature review

BACKGROUND

Patients receiving long-term home noninvasive ventilation (NIV) may slow down the progression to acute exacerbation of chronic obstructive pulmonary disease (AECOPD), however, the problem with respiratory instability during sleep diminished was persisted, which may reduce the effectiveness of NIV and the patient's quality of life. A novel NIV mode with volume-assured pressure support (VAPS) has been gradually applied to improve sleep quality in COPD patients with chronic respiratory failure. This meta-analysis aimed to evaluate the efficacy of VAPS in stable COPD patients with chronic respiratory failure.

METHODS

We performed an electronic literature search for RCTs from January 2008 to October 2018. Studies investigating the effects of VAPS in stable COPD patients with chronic respiratory failure were conducted, and the following primary outcomes were reviewed: effectiveness of ventilation, sleep quality, and quality of life.

RESULTS

Five studies with 150 subjects were identified. While questionnaire scores showed significant improvements in the VAPS mode, no significant difference was found in the effectiveness of ventilation (pH, MD = 0.01 [95% CI -0.01 to 0.02, P = 0.27]; PaCO₂, MD = 1.25 [95% CI -1.45 to 3.95, P = 0.37]; PaO₂, MD = 3.14 [95% CI -0.76 to 7.05, P = 0.11]; mSaO₂, MD = 0.23 [95% CI -1.22 to 1.67, P = 0.76]; mPtcCO₂, MD = 3.03 [95% CI -6.06 to- 0.60, P = 0.10]). The VAPS mode did not seem to ameliorate sleep quality and quality of life.

CONCLUSION

The VAPS mode had similar efficacy as the pressure-support (PS) mode. However, VAPS could significantly improve the patients' subjective feelings.

The effects of non-invasive mechanic ventilator modes on intraocular pressure in COPD patients with hypercapnic respiratory failure

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is not fully reversible disease that is characterized by progressive restricting airflow. Non-invasive mechanical ventilation (NIMV) treatment can be used in COPD patients who had type 2 respiratory failure. This study aimed to determine the effect of BPAP S/T and AVAPS modes on intraocular pressure (IOP), central corneal thickness (CCT) in 40 type 2 respiratory failure patients with COPD.

METHODS

Forty patients with type 2 respiratory failure who were hospitalized between June and December 2018 with the diagnosis of COPD exacerbations were included to the study. Patients followed up without NIMV for 12 hours after the end of exacerbations treatments end. After IOP, visual acuity and CCT were measured in all patients at the same time (11.00 am), same NIMV treatment was applied to the patients for 4 hours (AVAPS-BPAP S/T). Then the measurements were repeated. The effects of these NIMV modes on IOP were evaluated.

RESULTS

After NIMV treatment, it was observed that the mean IOP increased statistically significantly (13.3 vs 12.3 mm Hg; P = 0.001). After treatment with NIMV, there was a decrease for CCT close to statistical significance (P = 0.057) CONCLUSION: As a result; increased IOP and thinning of CCT after NIMV treatment has been shown. The type of NIMV and the level of inspiratory pressure needed in hypercapnic respiratory failure seem to affect IOP and it should be cautiously used to increase IOP.

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.

Comparing the effects and compliance between volume-assured and pressure support non-invasive ventilation in patients with chronic respiratory failure

INTRODUCTION

Standard bi-level non-invasive ventilation with fixed-level pressure support (PS) delivery may not maintain ventilation during the changes in pulmonary mechanics that occur throughout day and night, so average volume-assured pressure support (AVAPS) modes that target a preset volume by adjustment of PS may be effective.

OBJECTIVE

Our meta-analysis wants to compare AVAPS and pressure support non-invasive ventilation (PS-NIV) regarding arterial blood gases (ABGs), sleep efficiency and compliance.

METHOD

Relevant publications indexed in PubMed, Cochrane Library, Embase, Web of Science, Wanfang Data, China National Knowledge Infrastructure and VIPI were identified. Appropriate articles identified from the reference lists of the above searches were also reviewed. We included randomized controlled trials involved the use of AVAPS and PS-NIV ventilation for chronic respiratory failure. Each included study weighted mean differences, and 95% confidence intervals (CI) were calculated for continuous outcomes. Statistical heterogeneity was assessed using the I² value ≤ 50% were considered as no statistical heterogeneity and used fixed effects model. Otherwise, a random effects model was used.

RESULTS

Eight trials were eligible. No significant difference was observed between AVAPS and PS-NIV groups to compare PaCO₂ (OR -0.97, CI-2.54-0.61, P = 0.23) and PaO₂ (OR -1.81, CI-4.29-0.67, P = 0.15) in ABGs. There was no significant difference between the two groups with sleep efficiency (OR -3.31, CI-7.58-0.95, P = 0.13) and visual analog scale (OR 0.32, CI-6.97-7.61, P = 0.93).

CONCLUSIONS

The evidence shows there is no significant difference in clinical outcomes when comparing AVAPS and PS-NIV used for chronic respiratory failure patients.

Effects of early introduction of non-invasive positive pressure ventilation based on forced vital capacity rate of change: Variation across amyotrophic lateral sclerosis clinical phenotypes

PURPOSE

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease associated with high morbidity and mortality. We evaluated the ability of pulmonary function tests to predict disease progression by ALS clinical phenotypes, and the timing of the introduction of non-invasive positive pressure ventilation (NIPPV).

MATERIALS AND METHODS

A cohort study was performed in all adult patients who fulfilled El Escorial criteria at a tertiary-care academic medical centre for veterans in the USA from 1 January 2010 to 31 December 2014. Eligible patients underwent sitting and supine forced vital capacity (FVC) and the FVC rate of change (RoC) per month was calculated. ALS Functional Rating Scale-Revised (ALSFRS-R) scores were collected.

RESULTS

A total of 137 patients were included in our analysis. The average survival from ALS onset was 31.40 (±40.04) months. The general cohort median (IQR) RoC was -0.87 (-2.55 to 0.34)/-0.65 (-2.55 to 0.70) % per month (P = 0.81) of the sitting/supine FVC, respectively. However, mean monthly RoC varied among the ALS phenotypes, with higher variation among global ALS, where greater decline in RoC was noted. The average time from ALS onset to tracheostomy was 27.88 (±22.21) months. The average sitting/supine FVC RoC for subjects requiring tracheostomy was -2.86 (±3.77)/-3.63 (±3.75) at the time of tracheostomy, compared to -1.190 (±2.38)/-1.07 (±3.78) for those who did not require the procedure. Although NIPPV use did not result in statistically significant improvements in either the sitting or supine FVC %, it did slow the RoC decline of patients with global ALS phenotypes.

CONCLUSIONS

Initiation of NIPPV based on decline in RoC rather than the absolute value of either sitting or supine FVC may result in early stabilisation of ALS patients' pulmonary deterioration for the global clinical phenotype, and thus may have the potential for prolonging survival until tracheostomy or death.

Unusual case of central alveolar hypoventilation

Central alveolar hypoventilation is rarely encountered. This case report describes a young woman who was recently diagnosed with hypertension and ischemic heart disease. She presented to the emergency room with hypercapnic respiratory failure, for which she was mechanically ventilated. This was preceded by an acute upper respiratory tract infection. She was initially suspected to have Guillain-Barré syndrome, but further investigations ruled out neuromuscular or autoimmune disorders. Sleep-related hypoventilation was suspected after she experienced recurrent apneas at night that resulted in re-intubation. Polysomnographic studies confirmed episodes of central apnea and hypopnea during sleep, with significant carbon dioxide retention and oxygen desaturations. She required nocturnal ventilation via a tracheostomy tube until a diaphragmatic pacer could be placed. Using bi-level positive airway pressure and average volume-assured pressure support together with the diaphragmatic pacer, adequate ventilation during sleep was achieved.

Noninvasive auto-titrating ventilation (AVAPS-AE) versus average volume-assured pressure support (AVAPS) ventilation in hypercapnic respiratory failure patients

Auto-titrating noninvasive ventilation (NIV) has been developed as a new mode applying variable expiratory-positive airway pressure (EPAP) in addition to variable inspiratory pressures (IPAP), both to deliver targeted tidal volume (VT) and to eliminate upper airway resistance. The purpose of this study is to evaluate whether NIV with auto-titrating mode will decrease more PaCO₂ within a shorter time compared to volume-assured mode in hypercapnic intensive care unit (ICU) patients. The hypercapnic respiratory failure patients treated with average volume assured pressure support- automated EPAP mode (group1) were compared with those treated with average volume-assured pressure support mode (group2). Two groups were matched with each other according to baseline diagnoses, demographic characteristics, arterial blood gas values, target VT settings and daily NIV usage times. Built-in software was used to gather the ventilatory parameters. Twenty-eight patients were included in group 1, and 22 in group 2. The decrease in PaCO₂ had been achieved within a shorter time period in group 1 (p < 0.05). This response was more pronounced within the first 6 h (mean reduction in PaCO₂ was 7 ± 7 mmHg in group 1 and 2 ± 5 mmHg in group 2, p = 0.025), and significantly greater reductions in PaCO₂ (18 ± 11 mmHg in group 1 and 9 ± 8 mmHg in group 2, p = 0.008) and plasma HCO₃ levels (from 32 to 30 mEq and from 35 to 35 mEq, p = 0.007) took place within first 4 days. While mean IPAP was similar in both groups, maximum EPAP, mean VT and leak were significantly higher in group 1 than in group 2 (p < 0.05). Results of this preliminary study suggest that, this new auto-titrating NIV mode may provide additional benefit on volume-assured mode in decreasing PaCO₂ more efficiently and rapidly in hypercapnic ICU patients.

Targeted-Volume Noninvasive Ventilation Reduces Extubation Failure in Postextubated Medical Intensive Care Unit Patients: A Randomized Controlled Trial

Purpose

Till date, the benefit of using noninvasive ventilation (NIV) routinely after extubation to prevent reintubation has been conflicting. We aim to demonstrate the effect of targeted-volume NIV for the prevention of reintubation and extubation failure after planned extubation in medical intensive care unit (ICU) patients.

Study Design

This was a prospective, randomized controlled study.

Materials and Methods

Patients on invasive mechanical ventilation for more than 48 hrs for acute respiratory failure, who were ready for extubation, were randomized into targeted-volume NIV (intervention group) or oxygen mask (controlled group) immediately after extubation and continuously for 24 hrs.

Results

A total of 58 patients were enrolled in this study. The targeted-volume NIV group was observed to have a trend toward lower reintubation rate within 48 hrs compared to oxygen mask group (0% vs. 17.2%; P = 0.052). Extubation failure rate within 48 hrs was significantly lower in targeted-volume NIV group compared to oxygen mask group (0% vs. 41.38%; P < 0.001). There was a trend toward lower ICU length of stay (6[5] days vs. 10[8] days (median interquartile range [IQR]); P = 0.053) as well as shorter hospital length of stay after extubation (10[19] days vs. 18[15] days (median [IQR]); P = 0.059). There were no differences in the incidence of ventilator-associated pneumonia (VAP)/hospital-acquired pneumonia (HAP) (6.90% vs. 20.69%;P = 0.253) and 28 day-mortality (13.79% vs. 20.69%; P = 0.487).

Conclusions

Our study is the first study to demonstrate the benefit of application of targeted-volume NIV immediately after extubation in reducing extubation failure rate. There was a trend toward lowering reintubation rate and shorter ICU length of stay and hospital length of stay after extubation in mixed medical ICU patients.

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

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

Positive Airway Pressure Device Technology Past and Present: What's in the "Black Box"?

Since the introduction of continuous positive airway pressure (PAP) for the treatment of obstructive sleep apnea (OSA) in 1981, PAP technology has diversified exponentially. Compact and quiet fixed continuous PAP flow generators, autotitrating PAP devices, and bilevel PAP devices that can treat multiple sleep-disordered breathing phenotypes including OSA, central sleep apnea (CSA), combinations of OSA and CSA, and hypoventilation are available. Adaptive servo-ventilators can suppress Hunter-Cheyne-Stokes breathing and CSA and treat coexisting obstructive events. Volume-assured pressure support PAP apparatus purports to provide a targeted degree of ventilatory assistance while also treating cooccurring OSA and/or CSA.

AJRCCM: 100-Year Anniversary. Homeward Bound: A Centenary of Home Mechanical Ventilation

The evolution of home mechanical ventilation is an intertwined chronicle of negative and positive pressure modes and their role in managing ventilatory failure in neuromuscular diseases and other chronic disorders. The uptake of noninvasive positive pressure ventilation has resulted in widespread growth in home ventilation internationally and fewer patients being ventilated invasively. As with many applications of domiciliary medical technology, home ventilatory support has either led or run in parallel with acute hospital applications and has been influenced by medical and societal shifts in the approach to chronic care, the creation of community support teams, a preference of recipients to be treated at home, and economic imperatives. This review summarizes the trends and growing evidence base for ventilatory support outside the hospital.

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.

Advanced positive airway pressure modes: adaptive servo ventilation and volume assured pressure support

INTRODUCTION

Volume assured pressure support (VAPS) and adaptive servo ventilation (ASV) are non-invasive positive airway pressure (PAP) modes with sophisticated negative feedback control systems (servomechanism), having the capability to self-adjust in real time its respiratory controlled variables to patient's respiratory fluctuations. However, the widespread use of VAPS and ASV is limited by scant clinical experience, high costs, and the incomplete understanding of propriety algorithmic differences in devices' response to patient's respiratory changes. Hence, we will review and highlight similarities and differences in technical aspects, control algorithms, and settings of each mode, focusing on the literature search published in this area.

AREAS COVERED

One hundred twenty relevant articles were identified by Scopus, PubMed, and Embase databases from January 2010 to 2016, using a combination of MeSH terms and keywords. Articles were further supplemented by pearling. Recommendations were based on the literature review and the authors' expertise in this area. Expert commentary: ASV and VAPS differ in their respiratory targets and response to a respiratory fluctuation. The VAPS mode targets a more consistent minute ventilation, being recommended in the treatment of sleep related hypoventilation disorders, while ASV mode attempts to provide a more steady breathing airflow pattern, treating successfully most central sleep apnea syndromes.

Peer reviewers identified spin in manuscripts of nonrandomized studies assessing therapeutic interventions, but their impact on spin in abstract conclusions was limited

OBJECTIVES

To describe the impact of peer reviewers on spin in reports of nonrandomized studies assessing a therapeutic intervention.

STUDY DESIGN AND SETTING

This is a systematic review and retrospective before-after study. The sample consists of primary reports (n = 128) published in BioMed Central Medical Series journals between January 1, 2011, and December 31, 2013. The main outcome measures are the following: number and type of spin examples identified, deleted, or added by peer reviewers in the whole manuscript; number of reports with spin in abstract conclusions not detected by peer reviewers; the level of spin (i.e., no, low, moderate, and high level of spin) in the abstract conclusions before and after the peer review.

RESULTS

For 70 (55%) submitted manuscripts, peer reviewers identified at least one example of spin. Of 123 unique examples of spin identified by peer reviewers, 82 (67%) were completely deleted by the authors. For 19 articles (15%), peer reviewers requested adding some spin, and for 11 (9%), the spin was added by the authors. Peer reviewers failed to identify spin in abstract conclusions of 97 (76%) reports.

CONCLUSION

Peer reviewers identified many examples of spin in submitted manuscripts. However, their influence on changing spin in the abstract conclusions was low.

New modes in non-invasive ventilation

Non-invasive ventilation is useful to treat some forms of respiratory failure. Hence, the number of patients receiving this treatment is steadily increasing. Considerable conceptual and technical progress has been made in the last years by manufacturers concerning this technique. This includes new features committed to improve its effectiveness as well as patient-ventilator interactions. The goal of this review is to deal with latest advances in ventilatory modes and features available for non-invasive ventilation. We present a comprehensive analysis of new modes of ventilator assistance committed to treat respiratory failure (hybrid modes) and central and complex sleep apnea (adaptive servo ventilation), and of new modes of triggering and cycling (neurally adjusted ventilatory assist). Technical aspects, modes of operation and settings of these new features as well as an exhaustive review of published data, their benefits and limits, and the potential place of these devices in clinical practice, are discussed.

The use of volume-assured pressure support noninvasive ventilation in acute and chronic respiratory failure: a practical guide and literature review

Noninvasive positive pressure ventilation (NPPV) is an important tool in the management of acute and chronic respiratory failure. Traditionally, continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BPAP) have been the most commonly utilized modes for these purposes. Newer hybrid modes of NPPV, such as average volume-assured pressure support (VAPS), combine the properties of both volume- and pressure-controlled NPPV and represent another tool in the treatment of acute and chronic respiratory failure. Evidence demonstrating the superiority of VAPS over BPAP is sparse, but there have been studies that have demonstrated comparable efficacy between the two modes. The use of VAPS in acute hypercapnic respiratory failure has shown better clearance of CO2 compared to BPAP, due to its property of delivering a more assured tidal volume. This, however, did not lead to a decrease in hospital-days or improved mortality, relative to BPAP. The studies evaluating VAPS for chronic respiratory failure involve small sample sizes but have shown some promise. The benefits noted with VAPS, however, did not translate into increased survival, decreased hospitalizations or improved quality of life compared to BPAP. The limited evidence available suggests that VAPS is equally effective in treating acute and chronic respiratory failure compared to BPAP. Overall, the evidence to suggest superiority of one mode over the other is lacking. There is a need for larger studies before firm conclusions can be made.

Classification and prevalence of spin in abstracts of non-randomized studies evaluating an intervention

Background

Spin represents specific reporting strategies, either intentional or unintentional, to convince the reader that the beneficial effect of the experimental intervention in terms of efficacy and safety is greater than that shown by the results. The objectives of this study were to 1) develop a classification of spin specific to non-randomized studies assessing an intervention and 2) estimate the prevalence of spin in abstracts of reports of such studies.

Methods

In a first step, we developed a specific classification of spin for non-randomized studies by a literature review and pilot study. In a second step, 2 researchers trained in the field of methodology evaluated the prevalence of spin in the abstract of all non-randomized studies assessing an intervention published in the BioMed Central Medical Series journals between January 1, 2011 and December 31, 2013. All disagreements were resolved by consensus. We also determined whether the level of spin in abstract conclusions was high (spin reported without uncertainty or recommendations for further trials), moderate (spin reported with some uncertainty or recommendations for further trials) or low (spin reported with uncertainty and recommendations for further trials).

Results

Among the 128 assessed articles assessed, 107 (84 %) had at least one example of spin in their abstract. The most prevalent strategy of spin was the use of causal language, identified in 68 (53 %) abstracts. Other frequent strategies were linguistic spin, inadequate implications for clinical practice, and lack of focus on harm, identified in 33 (26 %), 25 (20 %), and 34 (27 %) abstracts respectively. Abstract conclusions of 61 (48 %) articles featured a high level of spin.

Conclusion

Abstract of reports of non-randomized studies assessing an intervention frequently includes spin. Efforts to reduce the prevalence of spin in abstract for such studies are needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-015-0079-x) contains supplementary material, which is available to authorized users.

Nocturnal respiratory failure in a child with congenital myopathy - management using average volume-assured pressure support (AVAPS)

This is a case report of the effective use of bi-level positive airway pressure support (BPAP) using the volume-assured pressure support feature in a pediatric patient with a congenital myopathy and significant nocturnal hypoventilation. Our patient was started on nocturnal nasal mask BPAP but required high pressures to improve her oxygen saturations and CO₂ baseline. She was then trialed on a BPAP machine with the volume-assured pressure support feature on. The ability of this machine to adjust inspiratory pressures to give a targeted tidal volume allowed the patient to be on lower pressure settings for periods of the night, with the higher pressures only when required. She tolerated the ventilation well and her saturations, CO₂ profiles, and clinical condition improved. This case report highlights the benefits of the volume-assured pressure support feature on a BPAP machine in a child with a neuromuscular disorder.

Chronic hypoventilation syndromes and sleep-related hypoventilation

Chronic hypoventilation affects patients with disorders on any level of the respiratory system. The generation of respiratory impulses can be impaired in congenital disorders, such as central congenital alveolar hypoventilation, in alterations of the brain stem or complex diseases like obesity hypoventilation. The translation of the impulses via spinal cord and nerves to the respiratory muscles can be impaired in neurological diseases. Thoraco-skeletal or muscular diseases may inhibit the execution of the impulses. All hypoventilation disorders are characterized by a reduction of the minute ventilation with an increase of daytime hypercapnia. As sleep reduces minute ventilation substantially in healthy persons and much more pronounced in patients with underlying thoraco-pulmonary diseases, hypoventilation manifests firstly during sleep. Therefore, sleep related hypoventilation may be an early stage of chronic hypoventilation disorders. After treatment of any prevailing underlying disease, symptomatic therapy with non-invasive ventilation (NIV) is required. The adaptation of the treatment should be performed under close medical supervision. Pressure support algorithms have become most frequently used. The most recent devices automatically apply pressure support and vary inspiratory and expiratory pressures and breathing frequency in order to stabilize upper airways, normalize ventilation, achieve best synchronicity between patient and device and aim at optimizing patients' adherence.

Positive airway pressure therapy for heart failure

Heart failure (HF) is a life-threatening disease and is a growing public health concern. Despite recent advances in pharmacological management for HF, the morbidity and mortality from HF remain high. Therefore, non-pharmacological approaches for HF are being developed. However, most non-pharmacological approaches are invasive, have limited indication and are considered only for advanced HF. Accordingly, the development of less invasive, non-pharmacological approaches that improve outcomes for patients with HF is important. One such approach may include positive airway pressure (PAP) therapy. In this review, the role of PAP therapy applied through mask interfaces in the wide spectrum of HF care is discussed.

Noninvasive ventilation in acute respiratory failure

After the institution of positive-pressure ventilation, the use of noninvasive ventilation (NIV) through an interface substantially increased. The first technique was continuous positive airway pressure; but, after the introduction of pressure support ventilation at the end of the 20th century, this became the main modality. Both techniques, and some others that have been recently introduced and which integrate some technological innovations, have extensively demonstrated a faster improvement of acute respiratory failure in different patient populations, avoiding endotracheal intubation and facilitating the release of conventional invasive mechanical ventilation. In acute settings, NIV is currently the first-line treatment for moderate-to-severe chronic obstructive pulmonary disease exacerbation as well as for acute cardiogenic pulmonary edema and should be considered in immunocompromised patients with acute respiratory insufficiency, in difficult weaning, and in the prevention of postextubation failure. Alternatively, it can also be used in the postoperative period and in cases of pneumonia and asthma or as a palliative treatment. NIV is currently used in a wide range of acute settings, such as critical care and emergency departments, hospital wards, palliative or pediatric units, and in pre-hospital care. It is also used as a home care therapy in patients with chronic pulmonary or sleep disorders. The appropriate selection of patients and the adaptation to the technique are the keys to success. This review essentially analyzes the evidence of benefits of NIV in different populations with acute respiratory failure and describes the main modalities, new devices, and some practical aspects of the use of this technique.