Providing Optimal PEEP During Mechanical Ventilation for Obese Patients Using Esophageal Balloon

Study Overview
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Brief Summary
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This is a research study to determine if identifying an optimal level of positive end-expiratory pressure (PEEP) targeted specifically to individualized patient characteristics will shorten the time on the ventilator. Participants will have catheter placed through the nose into the esophagus to measure the pressure inside the chest. This catheter will remain until the patient is freed from the ventilator. Participants will be randomized to usual care or to have the level of PEEP determined by the esophageal balloon pressure readings. The total time spent on the ventilator will be recorded.

Detailed Description
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Study Design: Randomized-controlled clinical trial. Patients will be enrolled within 4 days of mechanical ventilation and randomized 1:1 to titration of PEEP based on esophageal balloon pressures or based on the High PEEP ARDSnet PEEP/FiO2 (fraction of inspired oxygen) table. All patients will have esophageal balloons placed with baseline measurement of Ptp. Patients randomized to the intervention arm will then undergo titration of PEEP based on Ptp measurements to achieve Optimal PEEP, defined as end expiratory Ptp of 0 to +2 cm H2O.

Official Title
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Effect of Esophageal Pressure Measurement to Determine Optimal Positive End-expiratory Pressure Compared to Usual Care in Obese Patients Receiving Mechanical Ventilation

Conditions
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Obesity, Morbid, Ventilator-Induced Lung Injury, Respiratory Failure

Intervention / Treatment
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* Device: Esophageal balloon
* Procedure: Intervention Spontaneous Breathing Trial (SBT) and Extubation
* Procedure: Control Spontaneous Breathing Trial and Extubation
* Procedure: Intervention Weaning after Tracheostomy
* Procedure: Control Weaning after Tracheostomy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Body mass index greater than or equal to 40 Acute respiratory failure requiring mechanical ventilation Exclusion Criteria: Refusal to give consent by the subject or their legally authorized representative Abdominal compartment syndrome Chest tube for pneumothorax Having been on a ventilator for >4 days Suspicion of or known intracranial hypertension Anticipated extubation within 24 hours Chronic ventilator dependence Condition that precludes placement of an esophageal balloon (esophageal or nasopharyngeal pathology preventing insertion of the esophageal balloon catheter, severe thrombocytopenia or coagulopathy) Incarceration

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Optimal PEEP<br>The waveforms of airway pressure (Paw), esophageal pressure (Pes), and transpulmonary pressure (Ptp) will be visualized on the ventilator. Ptp is obtained from Paw - Pes. PEEP will be increased on the ventilator to achieve a Ptp between 0 and +2 cm H2O (Optimal PEEP). Measurements will be obtained daily and adjustments to PEEP will occur daily. PEEP will be reduced below Optimal PEEP in the setting of hemodynamic compromise (requiring increasing vasoactive medications for blood pressure support). | Device: Esophageal balloon<br>* All patients in both groups will have an esophageal balloon catheter inserted by a research investigator. The catheter will be inserted into their nare while upright (head of bed >30 degrees) to a depth slightly more than the estimated distance from the lower sternum to the back of the ear (typically around 60 cm). Gastric positioning will be confirmed with abdominal compression testing and the catheter then retracted 10 - 20cm into the lower esophagus. Placement will be confirmed with the presence of cardiac oscillations on the esophageal probe. The probe will then be secured to the patient's nasal opening using tape.<br>Procedure: Intervention Spontaneous Breathing Trial (SBT) and Extubation<br>* Patients in the Intervention group will undergo an SBT regardless of their PEEP level. The PEEP that generates a Ptp of 0 will be considered their optimal PEEP, and this will not be lowered for the SBT. The Intervention Group SBT will consist of a trial of a pressure support of 5 cm H2O and Optimal PEEP.<br>Procedure: Intervention Weaning after Tracheostomy<br>* Based on the use of optimal PEEP in this group, and the experience in the previous study protocol, the investigators will place patients in the Intervention group on Tracheostomy Collar Trial ONLY with a speaking valve. This simulates the normal process of utilizing the upper airway to maintain lung inflation that is performed automatically when a patient does not have an artificial airway.<br>|
| Active Comparator: ARDSNet High PEEP<br>PEEP in the control group will be determined by High PEEP ARDSnet PEEP/FiO2 table. Titration of PEEP will occur when clinically indicated by partial pressure of oxygen (PaO2) or oxygen saturation (SpO2), and FiO2. The investigators chose the High PEEP table based on the clinical suspicion that obese patients may require higher PEEP levels on average than non-obese patients to balance the additional pressure of their chest wall. In addition, EPVent2, a study of esophageal balloon PEEP titration in patients with ARDS utilized the High PEEP table. Patients with moderate and severe ARDS benefit from higher levels of PEEP. | Device: Esophageal balloon<br>* All patients in both groups will have an esophageal balloon catheter inserted by a research investigator. The catheter will be inserted into their nare while upright (head of bed >30 degrees) to a depth slightly more than the estimated distance from the lower sternum to the back of the ear (typically around 60 cm). Gastric positioning will be confirmed with abdominal compression testing and the catheter then retracted 10 - 20cm into the lower esophagus. Placement will be confirmed with the presence of cardiac oscillations on the esophageal probe. The probe will then be secured to the patient's nasal opening using tape.<br>Procedure: Control Spontaneous Breathing Trial and Extubation<br>* Patients in the Control group will undergo an SBT when they reach a PEEP ≤8 cm H2O. This is the current standard of care based on the SBT protocol at UNC Hospitals. SBT and extubation prior to meeting these criteria will be based on primary medical team's discretion and will be recorded for analysis and safety tracking.<br>Procedure: Control Weaning after Tracheostomy<br>* The control group will be placed on Tracheostomy Collar Trial with no requirement for speaking valve. They may utilize a speaking valve if tolerated and desired, but there is no requirement as there is in the Intervention group.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Ventilator-Free Days (VFD) by Day 28 | The number of days a patient is alive and free from the ventilator up to day 28. | 28 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Patients Reintubated | Intubated within 72 hours of extubation | 72 hours after extubation | 
| ICU Length of Stay | Number of days spent in the ICU | 28 days | 
| Hospital Length of Stay | Number of days spent in the Hospital | 28 days (can capture total length after patient is discharged) | 
| Number of Patients Receiving a Tracheostomy | Whether the patient required a tracheostomy to be liberated from the ventilator | during mechanical ventilation | 
| Number of Patients Extubated Early | Extubation prior to meeting established criteria (Control group only) | 28 days | 
| Highest Richmond Agitation and Sedation Scale | Measures the mental and physical state of a sedated patient. Range from -5 to +5. A score of 0 indicates a calm arousable patient, and is the ideal score. Will capture the highest score | during mechanical ventilation | 
| Lowest Richmond Agitation and Sedation Scale | Measures the mental and physical state of a sedated patient. Range from -5 to +5. A score of 0 indicates a calm arousable patient, and is the ideal score. Will capture the lowest score | during mechanical ventilation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Transpulmonary pressure, Esophageal balloon, Esophageal pressure monitoring, Mechanical ventilation