Skip to main content

Open Access Relationship Between Inspiratory Pressure and Tidal Volume in the Anesthetized Canine

Download Article:
(PDF 52 kb)


Hounds undergoing prolonged or complicated surgical procedures are often underventilated, as indicated by blood gas and end-tidal CO2(CO2) values when using published ventilatory guidelines. We investigated the relationship between body weight, tidal volume, and inspiratory pressure delivered by the ventilator (lung inflation pressure) in 59 anesthetized hounds (19 to 33 kg). Animals were ventilated under positive pressure control and noninvasively instrumented to monitor blood pressure, ECG, oxygen saturation, CO2, and tidal volume. Weight, sex, and thorax measurements were recorded. All dogs were monitored at lung inflation pressures of 10, 14, and 18 cm H2O, with measurements recorded once CO2 stabilized. Veterinary guidelines recommend tidal volumes of 10 to 15 ml/kg of body weight and lung inflation pressures of 15 to 25 cm H2O. When inflation pressure was below guidelines (10), tidal volume was “normal” (10 to 15 ml/kg), but the animals were underventilated. When inflation pressure was “normal” (14 or 18 cm H2O), tidal volume was above guidelines. Physiologic variables were normal only when inflation pressure was 14 cm H2O. Weight and thorax depth accounted for 32 and 6%, respectively, of tidal volume variability, and tidal volume varied by ±250 ml at any given body weight and inflation pressure. None of the measured physical variables accurately predicted tidal volume. These data suggest that the inconsistency in tidal volume is due to a previously undescribed variability in respiratory compliance in the anesthetized hound and that the guidelines for ventilation during surgery need further investigation.

Document Type: Research Article

Affiliations: Department of Comparative Medicine, Carolinas Medical Center, Charlotte, North Carolina

Publication date: February 1, 1998

More about this publication?
  • Comparative Medicine (CM), an international journal of comparative and experimental medicine, is the leading English-language publication in the field and is ranked by the Science Citation Index in the upper third of all scientific journals. The mission of CM is to disseminate high-quality, peer-reviewed information that expands biomedical knowledge and promotes human and animal health through the study of laboratory animal disease, animal models of disease, and basic biologic mechanisms related to disease in people and animals.

    Attention Members: To access the full text of the articles, be sure you are logged in to the AALAS website.

    Attention: please note, due to a temporary technical problem, reference linking within the content is not available at this time

  • Editorial Board
  • Information for Authors
  • Submit a Paper
  • Subscribe to this Title
  • Membership Information
  • Information for Advertisers
  • For issues prior to 1998
  • Institutional Subscription Activation
  • Ingenta Connect is not responsible for the content or availability of external websites

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Partial Open Access Content
Partial Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more