ABSTRACT
A Raman spectrometer multiple gas analyzer was used to monitor inspired and expired concentrations of oxygen (O2), nitrogen (N2), carbon dioxide (CO2), nitrous oxide (N2O), halothane, and isoflurane in 10 patients. The Raman spectrometer and a dedicated mass spectrometer were connected to each patient to provide a comparison of the two instruments. Results show that readings from the Raman spectrometer are within 0.62 vol% of known gas standards for O2, N2, N2O; within 0.03 vol% for CO2; and within 0.04 vol% for halothane, enflurane and isoflurane. Clinical results show that Raman spectrometer readings are within 1.36 vol% of the mass spectrometer readings for O2, N2, N2O; within 0.01 vol% for CO2; and within 0.22 vol% for halothane and isoflurane. The clinical and laboratory results indicate the Raman spectrometer monitors airway gases and vapors as accurately as a dedicated mass spectrometer.
Subject(s)
Anesthesiology/instrumentation , Operating Rooms , Spectrum Analysis, Raman/instrumentation , Environmental Monitoring/instrumentation , Evaluation Studies as Topic , Humans , Monitoring, Physiologic/instrumentationABSTRACT
Activated carbon is a high surface area adsorbent. Its ability to adsorb nitrogenous metabolic wastes and exogenous poisons from blood has been well documented. Polymeric coatings on activated carbon enhance its biotolerability and make it feasible for use in hemoperfusion devices. The only drawback seems to be the presence of microparticles on the carbon surface. These particles may become emboli during hemoperfusion. This paper describes a series of in vitro tests used to evaluate many commercially available granular and pelletized activated carbons. The tests were as follows: 1) creatinine adsorption capacity and kinetics, 2) initial cleanliness, 3) washability, 4) attrition resistance, and 5) carbon particle surface morphologymone grade of activated carbon has been chosen for hemoperfusion studies on the basis of the above evaluations; The nature of the microparticles and the approach used to remove them from this carbon is described.
