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

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Acute on Chronic Neuromuscular Respiratory Failure in the Intensive Care Unit: Optimization of Triage, Ventilation Modes, and Extubation

Critical care management of acute respiratory failure in patients with neuromuscular disease (NMD) such as amyotrophic lateral sclerosis (ALS) is not standardized and is challenging for many critical care specialists. Progressive hypercapnic respiratory failure and ineffective airway clearance are key issues in this patient population. Often at the time of hospital presentation, patients are already supported by home mechanical ventilatory support with noninvasive ventilation (NIV) and an airway clearance regimen. Prognosis is poor once a patient develops acute respiratory failure requiring intubation and invasive mechanical ventilatory support, commonly leading to tracheostomy or palliative-focused care. 

We focus on this understudied group of patients with ALS without tracheostomy and incorporate existing data to propose a technical approach to the triage and management of acute respiratory failure, primarily for those who require intubation and mechanical ventilatory support for reversible causes, and also for progression of end-stage disease. Optimizing management in this setting improves both quality and quantity of life.

Neuromuscular patients with acute respiratory failure require protocolized and personalized triage and treatment. Here, we describe the technical methods used at our single institution. The triage phase incorporates comprehensive evaluation for new etiologies of hypoxia and hypercapnia, which are not initially presumed to be secondary to progression or end-stage neuromuscular respiratory failure. In select patients, this may involve intubation or advanced adjustments of NIV machines. Next, once the acute etiology(s) is identified and treated, the focus shifts: training and use of mechanical airway clearance to optimize pulmonary function, facilitation of NIV wean or successful extubation to NIV, and transition to a stable regimen for home ventilation. The comprehensive protocol described here incorporates multi-institutional approaches and effectively optimizes acute respiratory failure in patients with neuromuscular pulmonary disease. 

Sleep-Related Breathing Disorders: When CPAP Is Not Enough

Three decades ago, continuous positive airway pressure (CPAP) was introduced to treat obstructive sleep apnea (OSA). Shortly after, bilevel positive airway pressure devices (BPAP) that independently adjusted inspiratory and expiratory positive airway pressure were developed to treat complex sleep-related breathing disorders unresponsive to CPAP. Based on the bilevel positive airway pressure platform (hardware) governed by propriety algorithms (software), advanced modes of noninvasive ventilation (NIV) were developed to address complex cardiorespiratory pathophysiology beyond OSA. This review summarizes key aspects of different bilevel PAP therapies (BPAP with/without backup rate, adaptive servoventilation, and volume-assured pressure support) to treat common sleep-related hypoventilation disorders, treatment-emergent central sleep apnea, and central sleep apnea syndromes.

Perioperative Care and Medication-related Hypoventilation

Cumulative evidence supports the association of adverse postoperative outcomes with obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS). Although current guidelines recommend preoperative screening for OSA and OHS, the best perioperative management pathways remain unknown. Interventions attempting to prevent complications in the postoperative period largely are consensus based and focused on enhanced monitoring, conservative measures, and specific OSA therapies, such as positive airway pressure. Until further research is available to improve the quality and strength of these recommendations, patients with known or suspected OSA and OHS should be considered at higher risk for perioperative cardiopulmonary complications.

Noninvasive volume-assured pressure support for chronic respiratory failure: a review

PURPOSE OF REVIEW

Noninvasive ventilation (NIV) is an established treatment for chronic hypercapnic respiratory failure (CRF). Volume-assured pressure support (VAPS) is a mode of NIV that automatically adjusts inspiratory pressure in order to maintain a constant respiratory volume. We aim to discuss the role and application of VAPS in CRF.

RECENT FINDINGS

Recently published meta-analyses and reviews fail to demonstrate a significant difference in gas exchange, sleep, or quality-of-life improvement between VAPS and bilevel positive airway pressure (BPAP) in patients with CRF. A recent manuscript suggests that VAPS therapy in chronic obstructive pulmonary disease patients may reduce the number of exacerbations. It has been shown that with a protocol-driven approach BPAP and VAPS can both be successfully titrated during a single split-night polysomnography.

SUMMARY

VAPS is as effective as other modes of NIV at improving ventilation and sleep in CRF. The potential advantage is a more consistent ventilatory support through daytime-nighttime variations and progression of disease over time. However, the impact on long-term outcomes, such as survival, has not been studied.

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.

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.