Abstract: A gas measurement probe for measuring gas tensions in liquid. The probe comprises a tubing having one end adapted for connection to a gas measurement device, such as a mass spectrometer, a gas chromatograph, an infrared spectrometer or a Raman spectrometer, among others. The second end of the probe is provided with a tip having at least one pore formed in it. The pore is filled with a membrane material which eliminates water from entering, but admits low molecular weight gases. These low molecular weight gases may then be identified by the measurement device.

Abstract: Cardiac output of a test individual is determined in a noninvasive method, by processing CO.sub.2 expirogram data obtained from the individual. The method also noninvasively determines pulmonary arterial blood CO.sub.2 concentration for the test individual. An apparatus for carrying out this noninvasive method includes a database of computed numerical CO.sub.2 expirograms, a device for measuring experimental CO.sub.2 expirogram data and means for processing the data sets to determine cardiac output.

Abstract: A mass spectrometer probe comprising a tubing having one end adapted for connection to a spectrometer and a second probe tip having a pore cut therethrough, the pore being sealed with a membrane such that the membrane eliminates water from the mass spectrometer system and admits low molecule weight gases into the system.

Abstract: A lung water computer system utilizing a single optical detection path. A single beam of visible (VIS) and infra-red (IR) radiation is chopped and filtered in at least two bandwidths centered on the absorption peaks of tracers such as indocyanine green (ICG) and deuterated water (DHO). The chopped, filtered beam is transmitted along the optical detection path to a densitometer cell provided with intersecting fluid and optical channels. The optical channels are milled to provide an accurate optical path length (OPL) across the fluid channel. The chopped filtered radiation traverses blood containing ICG and DHO in the fluid channel and is detected by a two color (VIS and IR) detector at the end of the optical detection path. The VIS and IR outputs of the detector are processed in separate electronic channels.