Abstract
Anesthesiologists are concerned with the effect of various anesthetics on a patient's central nervous ventilatory control. The most widely accepted method of determining the effect of a drug is to compare carbon dioxide response curves (Δ {Mathematical expression}e/ΔP etCO2, where {Mathematical expression}e = minute ventilation [in L/min] and PetCO2 = end-tidal carbon dioxide [in mm Hg]) measured before and after administration of the drug. Additional information concerning neuromechanical control can be obtained by also including a measure of the airway occlusion pressure (generally measured 100 ms after occlusion, i.e., P100). To facilitate these measurements we have developed a portable, computer-controlled data acquisition system. It includes an Apple II+ computer and measures {Mathematical expression}e, PetCO2, and P100. Each subject rebreathes exhaled carbon dioxide through a two-way breathing valve attached to a 9-liter reservoir, which is initially filled with 5% carbon dioxide and balance oxygen. Exhaled carbon dioxide concentrations are measured with an infrared medical gas analyzer on samples taken through a catheter connected at the mouthpiece. The exhaled flow is measured with a pneumotachograph in conjunction with a differential pressure transducer, and P100 is determined with a Validyne MP45 pressure transducer.
Original language | English (US) |
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Pages (from-to) | 198-202 |
Number of pages | 5 |
Journal | Journal of Clinical Monitoring |
Volume | 2 |
Issue number | 3 |
DOIs | |
State | Published - Jul 1986 |
Externally published | Yes |
Keywords
- Carbon dioxide
- Equipment
- Measurement techniques
- Statistics
- Ventilation
- carbon dioxide response curves
- central nervous ventilatory control
- computer data acquisition
- hypercapnic response
- linear regression
- ventilatory response
ASJC Scopus subject areas
- Critical Care and Intensive Care Medicine