A simple and portable breathing circuit designed for ventilatory muscle endurance training (VMET)

Balaban, Dahlia Y.; Regan, Rosemary; Mardimae, Alexandra; Slessarev, Marat; Han, Jay S.; Wells, Greg D.; Duffin, James; Iscoe, Steve; Fisher, Joseph A.; Preiss, David

doi:10.1016/j.rmed.2009.07.012

« Previous Next »Respiratory Medicine
Volume 103, Issue 12 , Pages 1822-1827, December 2009

A simple and portable breathing circuit designed for ventilatory muscle endurance training (VMET)

Dahlia Y. Balaban
- Department of Anesthesiology University Health Network, Toronto, Canada, Department of Physiology, University of Toronto, and Thornhill Research Inc., 70 Peter Street, 2^nd Floor Toronto, ON, Canada M5V 2G5
Rosemary Regan
- Department of Anesthesiology University Health Network, Toronto, Canada, Department of Physiology, University of Toronto, and Thornhill Research Inc., 70 Peter Street, 2^nd Floor Toronto, ON, Canada M5V 2G5
Alexandra Mardimae
- Department of Anesthesiology University Health Network, Toronto, Canada, Department of Physiology, University of Toronto, and Thornhill Research Inc., 70 Peter Street, 2^nd Floor Toronto, ON, Canada M5V 2G5
Marat Slessarev
- Department of Anesthesiology University Health Network, Toronto, Canada, Department of Physiology, University of Toronto, and Thornhill Research Inc., 70 Peter Street, 2^nd Floor Toronto, ON, Canada M5V 2G5
Jay S. Han
- Department of Anesthesiology University Health Network, Toronto, Canada, Department of Physiology, University of Toronto, and Thornhill Research Inc., 70 Peter Street, 2^nd Floor Toronto, ON, Canada M5V 2G5
Greg D. Wells
- Department of Anesthesiology University Health Network, Toronto, Canada, Department of Physiology, University of Toronto, and Thornhill Research Inc., 70 Peter Street, 2^nd Floor Toronto, ON, Canada M5V 2G5
James Duffin
- Department of Anesthesiology University Health Network, Toronto, Canada, Department of Physiology, University of Toronto, and Thornhill Research Inc., 70 Peter Street, 2^nd Floor Toronto, ON, Canada M5V 2G5
Steve Iscoe
- Department of Physiology, Queen's University, 18 Stuart Street, Botterell Hall, Kingston, Ontario, Canada K7L 3N6
Joseph A. Fisher
- Department of Anesthesiology University Health Network, Toronto, Canada, Department of Physiology, University of Toronto, and Thornhill Research Inc., 70 Peter Street, 2^nd Floor Toronto, ON, Canada M5V 2G5
- Corresponding author. Tel.: +1 416 710 6908; fax: +1 416 597 1330.
David Preiss
- Department of Anesthesiology University Health Network, Toronto, Canada, Department of Physiology, University of Toronto, and Thornhill Research Inc., 70 Peter Street, 2^nd Floor Toronto, ON, Canada M5V 2G5

Received 2 January 2009; accepted 19 July 2009. published online 13 August 2009.

Summary

Background

Ventilatory muscle endurance training (VMET) involves increasing minute ventilation () against a low flow resistance at rest to simulate the hyperpnea of exercise. Ideally, VMET must maintain normocapnia over a wide range of . This can be achieved by providing a constant fresh gas flow to a sequential rebreathing circuit. The challenge to make VMET suitable for home use is to provide a source of constant fresh gas flow to the circuit without resorting to compressed gas.

Methods

Our VMET circuit was based on a commercial sequential gas delivery breathing circuit (Pulmanex Hi-Ox, Viasys Healthcare, Yorba Linda, CA USA). Airflow was provided either by a small battery-driven aquarium air pump or by the entrainment of air down a pressure gradient created by the recoil of a hanging bellows that was charged during each inhalation. In each case, fresh gas flow was adjusted to be just less than resting . Eight subjects then breathed from the circuit for three 10min periods consisting of relaxed breathing, breathing at 20 and then at 40L/min. We monitored , end-tidal PCO₂ (PetCO₂) and hemoglobin O₂ saturation (SpO₂).

Results

During hyperpnea at 20 and 40L/min, PetCO₂ did not differ significantly from resting levels with either method of supplying fresh gas. SpO₂ remained greater than 96% during all tests.