Accession Number:

ADA224079

Title:

A Method to Determine Accuracy in End-Tidal Carbon Dioxide Monitoring

Descriptive Note:

Final rept.

Corporate Author:

NAVY EXPERIMENTAL DIVING UNIT PANAMA CITY FL

Personal Author(s):

Report Date:

1990-05-01

Pagination or Media Count:

17.0

Abstract:

An injection system was developed to determine the accuracy of end- tidal monitoring of carbon dioxide in a hyperbaric chamber. Sample tube diameter, flow rates, placement of reducing valves to control flow, and water traps were studied with sample tubes 34 m long from 1,000 to 150 feet of sea water FSW. A sensitive indicator of sample tube mixing in response time, defined as time to reach 90 of full scale deflection of a known calibration gas injection. From 1,000 to 380 FSW, ideal sample tube was Lee internal diameter 0.0.32 in and from 190 to 150 FSW, Nylaflow internal diameter 0.078 in. Sampling rate of 2,500 mlmin, controlled at depth, gave adequate response times of 240 to 320 msec for injections from 1,000 to 150 FSW. Controlling the flow at the surface, using water traps test tubes and sample flows less than 2,500 ml min prolonged the response time to unacceptable levels. This technique predetermines appropriate sample tube diameter and flow and eliminated sources of mixing to insure accurate end-tidal CO2 measurements. JES

Subject Categories:

  • Test Facilities, Equipment and Methods

Distribution Statement:

APPROVED FOR PUBLIC RELEASE