Impact of PAV Versus NAVA on Patient-Ventilator Synchrony and Respiratory Muscle Unloading

The purpose of this study is to determine whether two modes of artificial (i.e. mechanical) ventilation have an impact on patient synchrony with the ventilator (breathing machine) and on the patient's work of breathing.

Study Overview

• Status: Withdrawn
• Conditions: Respiratory Failure
• Intervention / Treatment: Procedure: PAV Ventilation; Procedure: NAVA Ventilation

Detailed Description

New, "intelligent" ventilator modes with more complex closed loops have been developed, some with a demonstrated clinical benefit. The modes of proportional assist ventilation (PAV) and neurally-adjusted ventilatory assist (NAVA) are capable of delivering ventilation proportional to patient effort and may be associated with improved patient-ventilator synchrony when compared to pressure support ventilation (PSV), a classic simple closed-loop assisted ventilation mode.

This study will study both modes of ventilation (PAV and NAVA) in each patient who is recruited, and measures of patient-ventilator synchrony and work of breathing will be taken during each mode.

Baseline data will be collected on a standardized volume-cycled control mode ventilator setting for 5 minutes and on a standardized pressure support ventilator mode for 25 minutes. Subjects will then be randomized to either PAV or NAVA ventilation and will be ventilated on that mode for 30 minutes. Equivalence of support levels between PAV and NAVA trials will be ensured by targeting the same peak (Ppeak) airway pressures. Data collected will include (but are not limited to) vital signs, sedation score, dyspnea assessment using visual analog scale, respiratory rate, tidal volume (Vt), peak airway pressure (Ppeak), inspiratory time and neural inspiratory time (Ti and Tni), total physiologic and neural respiratory cycle time (Ttot and Tntot), end-tidal CO2, esophageal pressure waveforms, waveforms of all ventilatory patterns, Edi waveforms, and peak Edi. Subjects will then be switched to the other mode of ventilation and undergo an identical 30-minute evaluation period with identical data collection. Arterial blood gas measurements will be done after any changes in ventilator settings only in subjects who have had arterial lines inserted for clinically-indicated reasons. This will be a replicate crossover study, meaning that all subjects that are initially randomized to one sequence (PAV-NAVA or NAVA-PAV) will afterwards be "crossed-over" to the other one. These two additional periods of measurements will allow us to account for potential carry over effects of the different interventions.

• Study Type: Interventional
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02114
      • Massachusetts General Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age 18 years or older
• Respiratory failure requiring mechanical ventilation
• Spontaneously breathing (able to generate flow/ pressure/ volume triggers on control modes of ventilation or on a mode of mechanically assisted spontaneous breathing)
• Requiring FiO2< 60% and PEEP< 10cm H2O to maintain oxygen saturations >90%

Exclusion Criteria:

• Pregnancy
• Inability to tolerate spontaneous breathing
• Gastro-esophageal pathology (including but not limited to recent gastric or esophageal surgery, history of varices, known anatomical gastric or esophageal defects such as strictures, hernias or fistulas)
• Agitation necessitating major sedative infusions
• Hemodynamic instability necessitating active adjustments in vasopressor therapy
• Coagulopathy
• New intracranial pathology (stroke, hemorrhage, meningitis, encephalitis)
• Paralyzed diaphragm

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PAV Ventilation; PAV is a mode of ventilation in which the only set parameter is the proportion of work/effort that is provided regardless of the ventilatory pattern the patient chooses- the patient has full control over pressure, volume, flow and time of inspiration as well as respiratory rate. In this mode, the ventilator measures patient respiratory mechanics every 10-15 breaths and delivers a level of pressure proportional to patient effort, thereby maintaining a set proportion of patient effort regardless of the patient's ventilatory pattern. The patients will be on this mode of ventilation for 60 minutes.	Procedure: PAV Ventilation; PAV is a mode of ventilation in which the only set parameter is the proportion of work/effort that is provided regardless of the ventilatory pattern the patient chooses- the patient has full control over pressure, volume, flow and time of inspiration as well as respiratory rate. In this mode, the ventilator measures patient respiratory mechanics every 10-15 breaths and delivers a level of pressure proportional to patient effort, thereby maintaining a set proportion of patient effort regardless of the patient's ventilatory pattern. The patients will be on this mode of ventilation for 60 minutes.
Experimental: NAVA Ventilation; With NAVA, delivery from the ventilator is triggered, controlled and cycled by the diaphragmatic EMG signal (Edi), which is measured by a specially designed nasogastric or orogastric catheter (NGT or OGT) containing EMG electrodes that cross the diaphragm. In this mode, the ventilator measures the Edi with each breath and instantaneously delivers a level of pressure proportional to Edi magnitude, thereby providing a set proportion of effort on a breath-to-breath basis. The patients will be on this mode of ventilation for 60 minutes.	Procedure: NAVA Ventilation; With NAVA, delivery from the ventilator is triggered, controlled and cycled by the diaphragmatic EMG signal (Edi), which is measured by a specially designed nasogastric or orogastric catheter (NGT or OGT) containing EMG electrodes that cross the diaphragm. In this mode, the ventilator measures the Edi with each breath and instantaneously delivers a level of pressure proportional to Edi magnitude, thereby providing a set proportion of effort on a breath-to-breath basis. The patients will be on this mode of ventilation for 60 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Patient-Ventilator Synchrony	Patient-ventilator synchrony will be assessed during both modes of ventilation. Data collected will include (but is not limited to) vital signs, sedation score, respiratory rate, tidal volume (Vt), peak airway pressure (Ppeak), inspiratory time and neural inspiratory time (Ti and Tni), total physiological and neural respiratory cycle time (Ttot and Tntot), waveforms of all ventilatory patterns, end-tidal CO2, esophageal pressure waveforms, Edi waveforms, and peak Edi.	2.5 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dyspnea Index	Patients who are able to interact (i.e. who are sufficiently awake and attentive) will undergo a dyspnea assessment, including a visual analogue scale for dyspnea.	2.5 hours
Respiratory Muscle Unloading	Respiratory muscle unloading, i.e. reduction of work of breathing by the patient, will be assessed during both modes of ventilation. Data collected will include (but is not limited to) vital signs, sedation score, respiratory rate, tidal volume (Vt), peak airway pressure (Ppeak), inspiratory time and neural inspiratory time (Ti and Tni), total physiological and neural respiratory cycle time (Ttot and Tntot), waveforms of all ventilatory patterns, end-tidal CO2, esophageal pressure waveforms, Edi waveforms, and peak Edi.	2.5 hours

Collaborators and Investigators

• Sponsor: Massachusetts General Hospital
• Investigators: Principal Investigator: Robert S Harris, MD, Massachusetts General Hospital

Study record dates

Study Major Dates

• Study Start: April 1, 2010
• Primary Completion (Actual): September 1, 2016
• Study Completion (Actual): September 1, 2016

Study Registration Dates

• First Submitted: March 11, 2013
• First Submitted That Met QC Criteria: March 11, 2013
• First Posted (Estimate): March 13, 2013

Study Record Updates

• Last Update Posted (Estimate): November 6, 2016
• Last Update Submitted That Met QC Criteria: November 4, 2016
• Last Verified: November 1, 2016

More Information

Terms related to this study

• Keywords: respiration, artificial
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Respiratory Insufficiency
• Other Study ID Numbers: 2013P000028