Effect of Alveolar Minute Ventilation on Respiratory Gas Heat Content

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).

Study Overview

• Status: Completed
• Conditions: Ventilation Perfusion Mismatch
• Intervention / Treatment: Other: controlled positive pressure ventilation 6ml/kg tidal volume; Other: controlled positive pressure ventilation 9ml/kg tidal volume

Detailed Description

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)

• Study Type: Observational
• Enrollment (Actual): 20

Contacts and Locations

Study Locations

• United States
  • California
    • Sacramento, California, United States, 95817
      • UC Davis Health System

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

adult patients without cardiac or respiratory illness

Description

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

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
6ml/kg; 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; controlled positive pressure ventilation 6ml/kg tidal volume
9ml/kg; 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; controlled positive pressure ventilation 9ml/kg tidal volume

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: University of California, Davis
• Investigators: Principal Investigator: Neal Fleming, MD, PhD, Professor, Anesthesiology & Pain Medicine

Study record dates

Study Major Dates

• Study Start: August 1, 2013
• Primary Completion (Actual): March 1, 2014
• Study Completion (Actual): March 1, 2014

Study Registration Dates

• First Submitted: September 11, 2013
• First Submitted That Met QC Criteria: September 11, 2013
• First Posted (Estimate): September 16, 2013

Study Record Updates

• Last Update Posted (Actual): October 28, 2019
• Last Update Submitted That Met QC Criteria: October 8, 2019
• Last Verified: October 1, 2019

More Information

Terms related to this study

• Keywords: mechanical ventilation; humidity; enthalpy
• Other Study ID Numbers: 483184