The Effect of High Frequency Percussive Ventilation on Cerebral Tissue Oxygenation

Study Overview
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Brief Summary
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Hypoxemia is commonly reported in patients admitted to the Intensive Care Unit (ICU) and may result from acute lung injury/acute respiratory distress syndrome (ALI/ARDS), sepsis, trauma and postoperative complications. In an attempt to preserve or increase the oxygenation, conventional mechanical ventilation is initiated in these patients. Unfortunately, patients frequently become refractory to standard ventilatory techniques and as such, gas exchange remains unaltered or becomes worse. High Frequency Percussive Ventilation (HFPV), on the other hand, is an advanced mode of ventilation which can be a salvage option in these patient cohorts as it has already been proven to improve gas exchange with success. The volumetric diffusive respirator (VDR-4; Percussionary, Corp., Sandpoint, ID) is the only commercially available system to deliver HFPV. This ventilator mechanically ventilates the lung by administering small successive subtidal volumes or percussions at unconventional high frequencies to reach an optimal diffusive oxygenation. Since it has been known that hypoxemia due to a reduced oxygenation results in secondary brain injury, it is conceivable that the cerebral tissue oxygenation might be impaired as well. It has been strongly suggested that a cerebral tissue oxygenation in the optimal range has an ameliorative influence on hypoxic events and in turn leads to a better clinical outcome. Thus far, no studies have been conducted to investigate if an improved oxygenation by means of a switch to HFPV automatically leads to an increment in the cerebral tissue oxygenation. With the use of Near-Infrared Spectroscopy (NIRS) technology, investigators will investigate whether this alternation of ventilation strategy is associated with a (beneficial) change of the cerebral tissue oxygenation.

Official Title
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The Effect of High Frequency Percussive Ventilation on Cerebral Tissue Oxygenation

Conditions
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Patients at the Intensive Care Unit (ICU)

Intervention / Treatment
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* Device: Near-Infrared Spectroscopy (NIRS)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients (age ≥ 18 years) at the Intensive Care Unit (ICU) who become refractory to conventional mechanical ventilation and are switched to HFPV. Exclusion Criteria: Age < 18 years Patients with COPD (chronic obstructive pulmonary disease) Patients with asthma

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: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: study group<br>Adult patients (age ≥ 18 years) at the Intensive Care Unit (ICU) who become refractory to conventional mechanical ventilation and are switched to HFPV. | Device: Near-Infrared Spectroscopy (NIRS)<br>* Near infrared spectroscopy (NIRS) is a non-invasive technique that uses near infrared light between 700 and 1100nm which penetrates several centimeters through skin and bone structures. Light is absorbed by chromophores. There are multiple chromophores which can be detected in the NIR spectrum such as water, lipids, melanin, myoglobin, oxygenated hemoglobin and deoxygenated hemoglobin. Each chromophore has a specific absorption spectrum. By using different wavelengths, it is possible to differentiate chromophores. The difference between oxygenated hemoglobin and deoxygenated hemoglobin can be calculated using the modified Beer-Lambert law, resulting in a numeric value which is a representation of the regional cerebral oxygen saturation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The association between HFPV and cerebral oxygen saturation | The primary objective is to investigate whether a switch from conventional mechanical ventilation to High Frequency Percussive Ventilation is associated with a change of the SctO2. Therefore, a comparison of SctO2-values two hours before and four hours after the switch will be made. | Two hours before switch to HFPV until 24 hours after the switch to HFPV |