Quantification of a number of molecular gases is required in clinical environments, i.e., respiratory and anesthitic gases, blood pO2 and pCO2, the toxic trace gases ethylene oxide, formaldehyde and escaped anesthetic agents and gases used for noninvasive lung function and cardiac output determinations. Raman light scattering provides a means of detecting and quantitating such gases. The development of a multichannel prototype instrument to detect respiratory and anesthetic gases in the operating room is addressed in this research. The prototype utilizes an Ar+ laser as the scattering source, and a microprocessor for signal counting, data processing and display control. The gas sample is oriented in the intracavity of a laser for enhanced optical power. Laser, optics, and detector innovations are proposed which should extend sensitivity to the ppm level. Multi channel monitoring of the entire Raman spectra for better resolution is also addressed via the evaluation of suitable spectral dispersive elements (concave holographic gratings and nonspherical holographic optical elements) and light detectors (PMT's, linear diode arrays and charge coupled devices). The prototypes applicability to monitor respiratory -anesthetic gases and blood p02 and pCO2 (via suitable sampling catheter) will be evaluated. Such a prototype bridges the gap between the previous fundamental research and preproduction designs.
| Davidson, Mayer B (2011) Diagnosing diabetes with glucose criteria: worshiping a false God. Diabetes Care 34:524-6 |
