Skip to main content

Comparison of the response of saline tonometry and an automated gas tonometry device to a change in CO2.

Publication ,  Journal Article
Noone, RB; Bolden, JE; Mythen, MG; Vaslef, SN
Published in: Crit Care Med
November 2000

OBJECTIVE: To examine the speed of response of saline tonometry and an automated gas tonometry system by using standard tonometry catheters. DESIGN: In vitro validation study. SETTING: Experimental research laboratory. INTERVENTIONS: Tonometry catheters were placed in a test chamber designed to simulate the lumen of a hollow viscus and were exposed to a rapid change in CO2 from 0% to 5% or 10%. Measured CO2 over time was fit to a mathematical model to determine the response time constant (the time to reach 63% of the final value) for each system. MEASUREMENTS AND MAIN RESULTS: Response time to a change in CO2 was significantly faster with the automated gas system than with traditional saline tonometry. The mathematical time constant for a 5% change in CO2 in a gas environment was 2.8 mins (95% confidence interval, 2.6-3.0 mins) for the gas and 6.3 mins (95% confidence interval, 5.8-7.3 mins) for the saline technique. These times were longer for the CO2 change in a liquid environment: The time constant was 4.6 mins (95% confidence interval, 4.5-4.7 mins) for the gas system and 7.8 mins (95% confidence interval, 7.15-8.6 mins) for the saline tonometry. There was a significantly lower final equilibration value for the CO2 measurement with saline tonometry. There was essentially no difference in time constants for each system for a 5% change compared with a 10% CO2 change, except for a slightly faster time constant for the gas tonometry system with a 5% change in the gas environment (5%: 2.8 mins vs. 10%: 3.3 mins). CONCLUSIONS: The automated gas tonometry system has a significantly faster response to a change in CO2 than conventional saline tonometry.

Duke Scholars

Published In

Crit Care Med

DOI

ISSN

0090-3493

Publication Date

November 2000

Volume

28

Issue

11

Start / End Page

3728 / 3733

Location

United States

Related Subject Headings

  • Signal Processing, Computer-Assisted
  • Regional Blood Flow
  • Reference Values
  • Models, Theoretical
  • Manometry
  • Intestinal Mucosa
  • Humans
  • Gastric Mucosa
  • Emergency & Critical Care Medicine
  • Critical Care
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Noone, R. B., Bolden, J. E., Mythen, M. G., & Vaslef, S. N. (2000). Comparison of the response of saline tonometry and an automated gas tonometry device to a change in CO2. Crit Care Med, 28(11), 3728–3733. https://doi.org/10.1097/00003246-200011000-00032
Noone, R. B., J. E. Bolden, M. G. Mythen, and S. N. Vaslef. “Comparison of the response of saline tonometry and an automated gas tonometry device to a change in CO2.Crit Care Med 28, no. 11 (November 2000): 3728–33. https://doi.org/10.1097/00003246-200011000-00032.
Noone RB, Bolden JE, Mythen MG, Vaslef SN. Comparison of the response of saline tonometry and an automated gas tonometry device to a change in CO2. Crit Care Med. 2000 Nov;28(11):3728–33.
Noone, R. B., et al. “Comparison of the response of saline tonometry and an automated gas tonometry device to a change in CO2.Crit Care Med, vol. 28, no. 11, Nov. 2000, pp. 3728–33. Pubmed, doi:10.1097/00003246-200011000-00032.
Noone RB, Bolden JE, Mythen MG, Vaslef SN. Comparison of the response of saline tonometry and an automated gas tonometry device to a change in CO2. Crit Care Med. 2000 Nov;28(11):3728–3733.

Published In

Crit Care Med

DOI

ISSN

0090-3493

Publication Date

November 2000

Volume

28

Issue

11

Start / End Page

3728 / 3733

Location

United States

Related Subject Headings

  • Signal Processing, Computer-Assisted
  • Regional Blood Flow
  • Reference Values
  • Models, Theoretical
  • Manometry
  • Intestinal Mucosa
  • Humans
  • Gastric Mucosa
  • Emergency & Critical Care Medicine
  • Critical Care