Abstract: The present invention is an apparatus and method for improving the detection of the inductance "signal" generated by an inductive plethysmograph (12). Signal detection is improved by modifying the design of the inductive plethysmograph (12) and also by improving the design of the associated circuitry. By virtue of these improvements, the associated circuitry may be located remotely rather than on the transducer, as is the current practice. In one aspect of the invention, the impedance matching transformer (14) joining the inductive plethysmograph (12) to the oscillator (16) is selected such that the inductance of its primary winding is greater than about ten times the reflected inductance of the inductive plethysmograph (12) and the cable (24) joining it to the transformer (14). In accordance with another aspect of the invention, the inductive plethysmograph (12) is modified such that the conductor (20) incorporated therein encircles the relevant body portion a plurality of times.

Abstract: An improved method for calibating a non-invasive apparatus for measuring respiration volume of the type wherein signals indicative of the rib cage and abdomen contributions to respiration volume are provided, and wherein at least one of the signals is multiplied by a predetermined weighting factor for reflecting the relative contributions of the rib cage and abdomen to respiration volume.The calibration method non-invasively determines the weighting factor by: totaling, during a period of breathing, a plurality of values of a parameter indicative of the relative amplitude, for each breath, of uncalibrated rib cage and abdomen signals; and dividing the average variability of the means of the total of the values of one of the rib cage and abdomen signals by the average variability of the mean of the tota of the values of the other signal. The quotient so derived represents the weighting factor.An apparatus for calibrating in accordance with the method is also disclosed.

Abstract: An apparatus and method for distinguishing between different types of apneic episodes. The method includes measuring a new index, TCD/VT, and measuring the phase relation between the abdominal and rib cage contributions to total respiration volume. The episode is classified as central, obstructive or mixed based on the value of TCD/VT and the phase relation.

Abstract: A method and an apparatus for administering a drug through a breathing passage for absorption on the mucous tissue of a patient includes introducing an aerosol of the drug into an expanded bag and bidirectional channel for communicating the drug with the breathing passage of the patient and otherwise is substantially impervious to the passage of air, collapsing the expanded bag while the bidirectional channel for communicating with the breathing passage is in position to deliver the drug into the breathing passage of the patient. A signal in a bidirectional channel indicates when the rate of passage of the drug exceeds a desirable limit, whereby the patient taking the drug is reminded to decrease the rate of collapse of the airbag, thereby maximizing drug utilization.

Abstract: Improved method for calibrating non-invasive system for measuring respiration volume of the type including apparatus for providing signals indicative of rib cage and abdominal contributions to respiration volume, device for multiplying the rib cage and abdominal signals by predetermined weighting factors reflecting the relative contributions of the rib cage and abdomen to respiration volume, and device for summing the weighted signals for providing a signal proportional to respiration volume.