Trial to Study Intubation Rates of Non-invasive Ventilation Using Pressure Support Ventilation (PSV) Versus Adaptive Support Ventilation (ASV) Mode in Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease
Condition: Chronic Obstructive Pulmonary Disease; Invasive Mechanical Ventilation; Adaptive Support Ventilation
MeSH terms: Lung Diseases; Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive
Study type: Interventional

Summary: 
      The clinical course of chronic obstructive pulmonary disease (COPD) is associated with
      recurrent episodes of exacerbation that results in respiratory failure. The treatment of
      respiratory failure is supportive and involves inhalation bronchodilators along with systemic
      steroids. In few cases the management of acute respiratory failure requires positive pressure
      ventilation (non-invasive or invasive). The use of NIV in acute exacerbation of COPD has
      resulted in significant reduction in morbidity and mortality. Although pressure support
      ventilation (PSV) allows the patient to influence the breathing pattern, ventilator-cycling
      criteria may worsen the patient-ventilator interaction, and severe asynchronies occur in up
      to 43% of patients undergoing NIV for ARF. Adaptive support ventilation (ASV) is a newer mode
      of ventilation that incorporates feedback mechanisms and thus provides a stable minute
      ventilation. We hypothesize that the use of ASV as a mode during ventilation using NIV in
      patients with acute exacerbation of COPD may result in reducing the duration of ventilatory
      support, need for intubation, and duration of intensive care unit (ICU) and hospital length
      of stay, when compared with PSV mode of NIV ventilation.
    

Detailed description: 
      Chronic obstructive pulmonary disease (COPD) is a common respiratory disease, which is
      characterized by airflow limitation. It affects more than 3.49 per cent of adults >35 year
      and is associated with high morbidity and mortality. The national burden of chronic
      bronchitis is estimated at 14.84 million.

      The clinical course of COPD is punctuated by acute exacerbations, which can lead to
      hypercapnic respiratory failure. The development of respiratory failure is associated with
      high morbidity and mortality, and significant healthcare costs. The requirement of
      ventilatory support also portends a reduced survival in this group of patients.

      The introduction of non-invasive ventilation (NIV) has resulted in a paradigm shift in the
      management of patients with acute exacerbation of COPD. First, reported in 1989, by Meduri et
      all, the successful application of NIV via full-face mask in 10 patients, and the avoidance
      of intubation in 8 of them (4 of 6 with COPD, 2 of 2 with congestive heart failure, and 2 of
      2 with pneumonia), demonstrated the efficacy of NIV in the management of acute exacerbation
      of COPD. This new modality was successful in avoiding of many of the complications associated
      with invasive mechanical ventilation.

      Traditionally, NIV is instituted with the pressure support mode of ventilation. Wherein, the
      inspiratory pressure was initiated at 6-8 cm of water and expiratory pressure was set at 3-4
      cm. The difference between the two pressures provided the ventilatory support. These
      pressures were then titrated based on patient clinical improvement by the physician.

      Adaptive support ventilation (ASV) is one of the newer modes of ventilation, described by
      Tehrani et al in 1991 and was designed to minimise the work of breathing, mimic natural
      breathing and stimulate breathing and reduce weaning time. It is a closed loop system, which
      incorporates various feedback mechanisms into its algorithm. The operator inputs patients
      weight, from that the ventilator calculates required minute alveolar ventilation assuming
      normal dead space fraction. Then an optimal frequency is calculated based on Otis equation.
      The target tidal volume is calculated by MV/f. The inspiratory pressure within a breath is
      controlled to achieve a constant value and between the breaths the inspiratory pressure is
      adjusted to achieve a target tidal volume. It aims to provide a target minute ventilation by
      adjusting automatically the delivered pressure and respiratory rate while keeping the work of
      breathing to a minimum by the patient.

      Due to its ability to reduce the work of breathing and meet the flow requirement of the
      patient by adjusting both the flow and respiratory rate depending on the respiratory
      mechanics, the use of ASV as a mode of ventilation during NIV may improve patient-ventilator
      synchrony. A study comparing ASV versus pressure support ventilation in intubated patients
      with acute exacerbation of COPD demonstrated that the use of ASV mode was associated with
      shorter weaning times with similar weaning success rates. However, a study comparing the use
      of ASV mode versus PSV mode during non-invasive ventilation has not been done previously.
      Patient-ventilator synchronization is critical for reducing the work of breathing and for
      successful NIV. Although PSV allows the patient to influence the breathing pattern,
      ventilator-cycling criteria may worsen the patient-ventilator interaction, and severe
      asynchronies occur in up to 43% of patients undergoing NIV for ARF. We hypothesize that the
      use of ASV as a mode during ventilation using NIV in patients with acute exacerbation of COPD
      may result in reducing the duration of ventilatory support, need for intubation, and duration
      of intensive care unit (ICU) and hospital length of stay, when compared with PSV mode of NIV
      ventilation.
    

Intervention name(s): Adaptive support ventilation; Pressure support ventilation
Intervention type(s): Other; Other
Intervention description(s): ASV during NIV; PSV during NIV
Other intervention name(s): ASV; PSV
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Other