NIV for Hypercapnic Respiratory Failure: AVAPS vs S/T BIPAP

The goal of this study is to compare two different modes of noninvasive ventilation in hypercapnic respiratory failure. The investigators will compare AVAPS and BIPAP S/T and hypothesize that AVAPS will result in a decreased length of stay in the ICU or on telemetry. Currently, noninvasive ventilation is the standard of care for hypercapnic respiratory failure. However, the most effective mode for patients with hypercapnic respiratory failure is unclear.

1. Overall Study Design and Plan This is a single center, randomized trial that will include a total of 100 adult subjects aged 18 or older with hypercapnic respiratory failure of all etiologies (i.e. "all comers"). The investigators will randomize patients in a single-blinded (patient blinded) fashion to BIPAP S/T or AVAPS during the duration of their hospitalization. The investigators will assess ABG at baseline, 1 hour after initial placement on BIPAP S/T or AVAPS, and between hours 24-48 of use. The investigators will record the pre-NIV pH and PaCO2, post-NIV pH and PaCO2, length of hospital stay in the medical ICU or telemetry unit, days on NIV, need for intubation (if occurred), transition to medical ICU care in patients who were initially admitted to telemetry, and in-hospital mortality. All collected laboratory data are already done as part of usual care for all patients placed on NIV when a patient is on the telemetry unit or medical ICU. The groups will undergo stratified randomization based on whether they are initially admitted to medical ICU or medical telemetry. Patients from medical ICU or telemetry units will be randomized to one of the following arms: Arm 1: AVAPS mode Arm 2 2: BIPAP S/T mode

Patients from medical ICU or telemetry units will be randomized to one of the following arms: Arm 1: AVAPS mode Arm 2: BIPAP S/T mode

Average Volume-Assured Pressure Support (AVAPS) setting on the noninvasive ventilator. The exact AVAPS setting will be titrated by the clinical team involved directly in the patient's care based on patient comfort and clinical response.

Bilevel Positive Airway Pressure Spontaneous Timed (BIPAP S/T) setting on the noninvasive ventilator. The exact BIPAP S/T setting will be titrated by the clinical team involved directly in the patient's care based on patient comfort and clinical response.

A setting on noninvasive ventilator that allows setting of maximum and minimum inspiratory pressure and sets a target tidal volume. The inspiratory pressure varies breath to breath to ensure pre-set tidal volume is delivered.

A setting on noninvasive ventilator that allows setting of inspiratory pressure, inspiratory time, expiratory pressure, and backup rate to deliver variable tidal volumes.

In patients admitted to the medical ICU, the primary endpoint is ICU length of stay. This will be the number of days a patient is admitted from day 1 of admission until the day of discharge. In patients admitted to medical telemetry unit, the outcome is telemetry length of stay. This will be the number of days a patient is admitted from day 1 of admission until the day of discharge.

Subgroup analysis (logistic regression or p-value) comparing outcomes 1- ICU or telemetry length of stay based on the underlying cause of hypercapnic respiratory failure

We will perform subgroup analysis of each cause of hypercapnic respiratory failure (such as COPD, pulmonary edema, altered mental status, etc) for these outcome- for 1. ICU or telemetry length of stay. We will use either logistic regression model or p-value to determine the difference for each subgroup. The results will be reported as difference between groups with statistical significance.

Subgroup analysis (logistic regression or p-value) comparing outcome 2- difference in paCO2 reported as difference between groups (with p-value and/or standard deviation)

We will perform subgroup analysis of each cause of hypercapnic respiratory failure (such as COPD, pulmonary edema, altered mental status, etc) for outcome 2- difference in PaCO2. We will use either logistic regression model or p-value to determine the difference for each subgroup. The results will be reported as difference between groups with statistical significance.

Subgroup analysis (logistic regression or p-value) comparing outcome 4- time to normalization of pH reported as difference between groups (with p-value and/or standard deviation)

We will perform subgroup analysis of each cause of hypercapnic respiratory failure (such as COPD, pulmonary edema, altered mental status, etc) for outcome 4- time to normalization of pH. We will use either logistic regression model or p-value to determine the difference for each subgroup. The results will be reported as difference between groups with statistical significance.

Subgroup analysis (logistic regression or p-value) comparing outcome 5- days on NIV reported as difference between groups (with p-value and/or standard deviation)

We will perform subgroup analysis of each cause of hypercapnic respiratory failure (such as COPD, pulmonary edema, altered mental status, etc) for outcome 5- days on NIV. We will use either logistic regression model or p-value to determine the difference for each subgroup. The results will be reported as difference between groups with statistical significance.

Subgroup analysis (logistic regression or p-value) comparing outcome 6- need for intubation reported as difference between groups (with p-value and/or standard deviation)

We will perform subgroup analysis of each cause of hypercapnic respiratory failure (such as COPD, pulmonary edema, altered mental status, etc) for outcome 6- need for intubation. We will use either logistic regression model or p-value to determine the difference for each subgroup. The results will be reported as difference between groups with statistical significance.

Subgroup analysis (logistic regression or p-value) comparing outcome 7- need for ICU stay reported as difference between groups (with p-value and/or standard deviation)

We will perform subgroup analysis of each cause of hypercapnic respiratory failure (such as COPD, pulmonary edema, altered mental status, etc) for outcome 7- need for ICU stay. We will use either logistic regression model or p-value to determine the difference for each subgroup. The results will be reported as difference between groups with statistical significance.

Inclusion Criteria: Provision of signed and dated informed consent form directly by the patient; consent can also be obtained via a legal patient representative/health care proxy/surrogate Stated willingness to comply with all study procedures and availability for the duration of the study Male or female, aged 18 or older Diagnosed with hypercapnic respiratory failure on admission (ABG) Admitted to Lenox Hill Hospital medical intensive care unit or telemetry unit Requiring noninvasive ventilation as determined by the treating physician for the treatment of hypercarbic respiratory failure Exclusion Criteria: Patients who require ventilation at predetermined tidal volumes Patients who require rapid and frequent IPAP adjustments to maintain a consistent tidal volume Age less than 18 years of age Currently intubated Chronic tracheostomy Pregnancy Hypotension Epistaxis (nosebleed) Untreated pertussis Acute sinusitis or Otitis media Patients at risk of aspirating gastric contents Patients with lack of spontaneous respiratory drive Patients with the inability to maintain a patent airway or adequately clear secretions Prisoners or other institutionalized individuals

Only researchers on involved in conducting the study will have access to the information collected in the study. 9.3 Data Handling and Record Keeping 9.3.1 Data Collection and Management All information accessed from the medical record will be de-identified. All data will be stored on an encrypted secure server, REDCap. 9.3.2 Confidentiality and Privacy Privacy will be protected as data will be collected within the Northwell Redcap data portal. All data will be de-identified prior to entry into REDCap. All communication between subjects and researchers will be conducted in a private setting.

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