Effect of Alveolar Minute Ventilation on Respiratory Gas Heat Content

Study Overview
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Brief Summary
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This is a single site, prospective, non-blinded, non-randomized, non-interventional study designed to evaluate the effect of changes in alveolar minute ventilation on the measurement of respiratory heat loss (enthalpy).

Detailed Description
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This is a single site, prospective, non-blinded, non-randomized, noninterventional study designed to evaluate the effect of changes in alveolar minute ventilation on the measurement of respiratory heat loss (enthalpy). Each patient will serve as their own control. The study will enroll adult patients without cardiac or respiratory illness. It is designed to evaluate the effect of the ventilatory pattern (tidal volume, rate) on respiratory heat loss measured using the VQm™ monitor during standard intra-operative clinical care that requires positive pressure ventilation (PPV)

Official Title
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Effect of Alveolar Minute Ventilation on Respiratory Gas Heat Content

Conditions
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Ventilation Perfusion Mismatch

Intervention / Treatment
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* Other: controlled positive pressure ventilation 9ml/kg tidal volume
* Other: controlled positive pressure ventilation 6ml/kg tidal volume


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age greater than 18 years scheduled for an elective surgical procedure with an anticipated duration of more than 2 hours requiring general anesthesia and positive pressure ventilation using an endotracheal tube patient status ASA 1, 2 or 3 no significant cardio-vascular or respiratory disease supine surgical position Exclusion Criteria: Adults unable to give primary consent age less than 18 years pregnancy prisoners pre-existing cardiac or pulmonary disease infusion of inotropic drugs positive end expiratory pressure (PEEP) requirements >8 cm H2O increased intra-abdominal pressure (e.g. planned surgical pneumoperitoneum or ascitis) intra-operative patient position other than supine

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| 6ml/kg<br>Enthalpy measured in patients receiving controlled positive pressure ventilation 6ml/kg Tidal volume. The VQm monitor samples the gas at a rate of 3 L/min, returning the analyzed gas to the circuit. As the exhaled gas passes through the analytical chamber, the temperature and humidity are measured essentially continuously (40Hz). These data are combined with pressure measurements to determine the exhaled gas volume and then the heat content (enthalpy) is calculated. | Other: controlled positive pressure ventilation 6ml/kg tidal volume<br>* controlled positive pressure ventilation 6ml/kg tidal volume<br>|
| 9ml/kg<br>Enthalpy measured in patients receiving controlled positive pressure ventilation 9ml/kg Tidal volume. The VQm monitor samples the gas at a rate of 3 L/min, returning the analyzed gas to the circuit. As the exhaled gas passes through the analytical chamber, the temperature and humidity are measured essentially continuously (40Hz). These data are combined with pressure measurements to determine the exhaled gas volume and then the heat content (enthalpy) is calculated. | Other: controlled positive pressure ventilation 9ml/kg tidal volume<br>* controlled positive pressure ventilation 9ml/kg tidal volume<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Airway Enthalpy | This is a single site, prospective, non-blinded, non-randomized, non-interventional study designed to evaluate the effect of changes in alveolar minute ventilation on the measurement of respiratory heat loss (enthalpy) in Joules per minute. | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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humidity, enthalpy, mechanical ventilation