Abstract: Microbeads include small preformed microbead substrates, which may comprise, for example, silica particles having a characteristic dimension less than 2 millimeters. A plurality of luminophores are applied to an exposed surface of the microbead substrates, wherein the luminophores are selected for detecting pressure and/or temperature. A plurality of luminophores absorb light at a predetermined wavelength to transition to an excited state, and they luminesce at different wavelengths when returning to the ground state. The luminescence may be phosphorescence or fluorescence. In some embodiments the microbeads include at least one pressure-sensitive luminophore, at least one temperature-sensitive luminophore, and at least one reference luminophore that is neither pressure-sensitive nor temperature-sensitive. In some embodiments the microbeads are configured for use in digital particle image velocimetry.

Abstract: Osmium-based oxygen sensor, pressure-sensitive paint that includes the osmium-based oxygen sensor, and method for measuring the pressure of an oxygen-containing fluid on a surface using the pressure-sensitive paint.

Abstract: A dual-luminophor compositions that include a first luminescent compound having a luminescent emission that is sensitive to oxygen concentration, a second luminescent compound having a luminescent emission that is insensitive to oxygen concentration, and an oxygen-permeable host material; and method for measuring the pressure of an oxygen-containing fluid using the dual-luminophor composition.

Abstract: Apparatus or systems which employ luminescence quenching to produce an oxygen concentration indicative signal. Components of such systems include: (1) an airway adapter, sampling cell, or the like having a sensor which is excited into luminescence with the luminescence decaying in a manner reflecting the concentration of oxygen in gases flowing through the airway adapter or other flow device; (2) a transducer which has a light source for exciting a luminescable composition in the sensor into luminescence and a light sensitive detector for converting energy emitted from the luminescing composition as that composition is quenched into an electrical signal indicative of oxygen concentration in the gases being monitored; and (3) subsystems for maintaining the sensor temperature constant and for processing the signal generated by the light sensitive detector. Sensors for systems of the character just described, methods of fabricating those sensors, and methods for installing the sensors in the flow device.

Abstract: Cardiac output is measured utilizing a catheter in conjunction with the indicator dilution technique. Non-thermal analyte-containing fluid is used as the injectate. This fluid is biocompatible with and metabolizable within the body of the patient. An analyte concentration sensor is mounted upon the catheter and located downstream within the bloodstream from the port from which the analyte-containing fluid is expressed. Because of the matching of rapid concentration sensor response with an analyte-containing fluid which is metabolizable, the measurement of cardiac output may be carried out as often as about one to three minutes in conjunction with an infusion interval substantially less than the measurement frequency interval. The analyte-containing fluids are selected from a group consisting of ammoniacal fluid, heparin, ethanol, a carbon dioxide releasing fluid, glucose, and anesthesia agent.

Abstract: A method for converting a value for the partial pressure of oxygen (pO.sub.2) in blood at a measurement temperature to a corresponding value at a reference temperature (37.degree. C.). A value for pO.sub.2 is determined by measurements made in a patient's blood stream using a phosphorescent compound that is sensitive to the concentration of oxygen. The phosphorescent compound is illuminated with a short pulse of light, causing it to produce a phosphorescent emission having a rate of decay that varies as the function of the partial pressure of oxygen in the blood surrounding the phosphorescent compound. A detector produces an electrical signal corresponding to the intensity of the phosphorescent emission, and the electrical signal is converted to a corresponding digital value for input to a microcomputer. Also supplied to the microcomputer in digital form is a signal indicative of the temperature at the measurement site where the phosphorescent compound is disposed.

Abstract: A CO.sub.2 /O.sub.2 or pH/O.sub.2 gas sensor comprising a single optical fiber and a method for making the same. The optical fiber carries light signals at different wavelengths for monitoring either CO.sub.2 concentration or pH level, in combination with O.sub.2 concentration. Attached to the distal end of the fiber-optic probe is a cylindrical pellet that has one surface covered by a light reflective material (gold foil) and the other surface attached adjacent to the distal end of the optical fiber. Depending on whether the sensor is to monitor either CO.sub.2 or pH, the pellet comprises either a CO.sub.2 analyte indicator molecule or a pH analyte indicator molecule covalently bonded to a polymer matrix material. Also adjacent to the distal end of the optical fiber is disposed a second polymer matrix material which is codissolved with an O.sub.2 analyte reactive indicator molecule.

Abstract: Methods of and luminescent substances for measuring oxygen concentration of a test fluid. A test fluid is contacted with a plastic film containing a luminescent substance, the luminescent emission intensity of which is quenched in the presence of oxygen. The film is subjected to irradiation by light that is strongly absorbed by the luminescent substance, and a measure of the time dependence of luminescent emission intensity I(t) is obtained. Three modes of measuring quenching, and thus the oxygen concentration, from I(t) are described. These modes are insensitive to variation in plastic thickness, concentration of the luminescent substance, and take into account the non-exponential decay of the emission, thereby extending the range over which the film is sensitive. The luminescent substances include metallo derivatives of partially or fully fluorinated porphyrins which are photostable due to the fluorination of the porphyrin ring.

Abstract: Methods and compositions are described for measuring oxygen concentration, particularly for monitoring oxygen in the blood with a fiber optic catheter. Oxygen concentration is determined by observing quenching of the emission from a luminescent (phosphorescent of fluorescent) molecule embedded in an oxygen-permeable matrix. A test fluid of unknown oxygen concentration is contacted with the matrix containing at least one luminescent substance. The matrix is subjected to irradiation over some period of time by light of a wavelength that is strongly absorbed by the luminescent substance, and a measure of the time dependence of luminescent emission intensity I(t) is obtained. Three modes of determining oxygen concentration from I(t) are described.