Clinical trial NCT01666054: Comparison of Weaning on Pressure Support vs. Proportional Assist Ventilation: A Pilot Study
Official title: Is Respiratory Rate an Adequate Indicator of Respiratory Distress During Weaning? A Comparison of Weaning on Pressure Support vs. Proportional Assist Ventilation.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Weaning From Mechanical Ventilation
Keywords: Weaning
mechanical ventilation
Proportional Assist Ventilation
Lead sponsor: London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's
Sponsor class: OTHER
Collaborators: name: Medtronic - MITG
name: University of Western Ontario, Canada
First posted: 2012-08-16
Enrollment: 54
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: The study hypothesis is that reducing patient-ventilator asynchrony will reduce time required to wean from mechanical ventilation. The purpose of this pilot study is (1) to assess study feasibility in terms of recruitment, protocol adherence and efficacy of the intervention for reducing asynchrony, (2) to assess baseline rates of asynchrony and outcomes in the control arm in order to perform sample size calculations, if needed, for further, larger studies designed to detect differences in weaning time in specific, predefined populations and (3) to examine how often ineffective triggering (and therefore reduced ventilator respiratory rate) at higher levels of pressure support lead to a false conclusion that higher levels of support are needed to diminish respiratory distress.

Detailed description: Previous research has shown that approximately twenty-five percent of patients capable of triggering the ventilator in assisted modes have high rates of patient-ventilator asynchrony, and that such patients have a longer duration of mechanical ventilation. It is not known whether asynchrony is a cause of weaning failure or simply a marker of more severe respiratory failure. The most common type of asynchrony, ineffective triggering, may be both a marker of respiratory disease and a cause of delayed weaning. During ineffective triggering, the patient's inspiratory effort fails to trigger a ventilator breath, and thus the respiratory rate displayed on the ventilator underestimates the patient's true, intrinsic respiratory rate. Since ineffective triggering is more common at higher levels of pressure support than lower levels, an increase in respiratory rate during weaning of pressure support may indicate the development of respiratory distress or simply the abolition of ineffective triggering. Ineffective triggering may also cause delayed weaning because respiratory muscle energy is "wasted" on non-supported breaths. Proportional assist ventilation (PAV) is an FDA- and HPB-approved mode of ventilation in which the ventilator applies pressure in proportion to patient effort. Using PAV, patient-ventilator interaction may be optimized and ineffective triggering greatly reduced. Since the patient and ventilator respiratory rates are generally equivalent, a reduction in respiratory rate with increasing ventilatory support is less likely to be false positive indication of the need for greater assistance.

In this study, patients with difficulty weaning from mechanical ventilation will be randomized to weaning with one of two weaning protocols: Proportional Assist Ventilation (PAV) weaning algorithm (intervention arm) vs. Pressure Support Ventilation (PSV) weaning algorithm (control arm).

Eligibility criteria: Inclusion Criteria:

* Age 18 years or greater
* Mechanically ventilated patients who are ready to begin weaning according to prespecified eligibility criteria, and tolerate thirty minutes of pressure support ventilation (PSV), but are not ready for extubation, defined as an frequency to tidal volume (f/Vt) greater-than (\>) 105 after two minutes of constant positive airway pressure (CPAP)
* Reason for intubation partially or completely reversed

Exclusion Criteria:

* Tolerating PSV 5 greater-than (\>)2 hrs (Weaned)
* Plan to extubate today
* Extubated today
* Considering Withdrawal of life support (less-than (\<)48hrs)
* Neurosurgical patient
* High SC injury/ progressive NMD
* Tracheostomy at time of ICU admission
* Has met all weaning eligibility and been on Pressure Support Ventilation (PSV) \>36 hours

Primary outcomes:
measure: Duration of weaning
timeFrame: From time of randomization up to 28 days
Secondary outcomes:
measure: Change in asynchrony index from baseline
timeFrame: Measurement of flow, airway pressure, and estimate of respiratory muscle pressure recorded at baseline then again, at high and at low levels of support during the first seven days of the weaning protocol
measure: Change in sedative drug administration from baseline
timeFrame: Daily dose of sedative drugs administered at baseline and day 1, 3, and 7 of study protocol
measure: Delirium
timeFrame: Up to 28 days post randomization
Other outcomes:
measure: Tolerance of weaning mode
timeFrame: Daily, up to 28 days post randomization
measure: Indication for increased ventilatory support
timeFrame: Daily
Locations:
city: London
country: Canada
facility: London Health Sciences Centre - University Hospital
state: Ontario
Study officials:
affiliation: London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's
name: Karen J Bosma, MD, FRCPC
role: PRINCIPAL_INVESTIGATOR
References:
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citation: Bosma KJ, Read BA, Bahrgard Nikoo MJ, Jones PM, Priestap FA, Lewis JF. A Pilot Randomized Trial Comparing Weaning From Mechanical Ventilation on Pressure Support Versus Proportional Assist Ventilation. Crit Care Med. 2016 Jun;44(6):1098-108. doi: 10.1097/CCM.0000000000001600.