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: A method and apparatus are shown for monitoring respiration volumes by continuously measuring, while the patient breathes, variations in the patient's chest cross sectional area, or preferably, variations in both chest and abdomen areas. Each area is measured by measuring the inductance of an extensible electrical conductor closely looped around the body, by connecting the loop as the inductance in a variable frequency LC oscillator followed by a frequency-to-voltage converter and a voltage display. Calibration is made by measuring the area variations for a few breaths while directly measuring corresponding volumes of breath, preferably while the patient assumes at least two body positions, for example sitting and supine. The method and apparatus may also be used to monitor changes in area of any non-magnetic object.

Abstract: An improved, low-cost stretchable band incorporating a conductor for disposition about the human torso or other three dimensional object, and particularly intended for use with respiration monitoring apparatus, is disclosed. A method for making the band, which method is suitable to mass production techniques, is also disclosed. Also presented is an improved enclosure housing circuitry releasably connected to the conductor in the band when the band is incorporated in respiration monitoring apparatus.

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: The presence and origin of apnea in a newborn subject is detected by separately and concurrently monitoring relative movement of the cranial bones and nasal ventilation. The cranial bones have been found to move with respiration as a function of intrapleural pressure, and monitoring of their movement is accordingly used to generate a signal representative of intrapleural pressure. A nasal cannula, thermistor, thermocouple or CO.sub.2 sensors are employed to concurrently generate a signal representative of tidal volume. Absence of changes in both cranial bone movement and respiratory air flow at the nose is indicative of the presence of central apnea, while absence of nasal air flow accompanied by continuing cranial bone movements is indicative of obstructive apnea. The preferred device for detecting cranial bone movement is a surface inductive plethysmographic transducer, although other suitably sensitive motion detecting devices may be employed.

Abstract: A method for monitoring cardiopulmonary events is disclosed. The basic method comprises looping an extensible conductor (14) in close encircling relation about the neck (12) of the subject (10), providing a signal indicative of the inductance of the loop, and monitoring the signal. This signal contains both qualitative and quantitative cardiopulmonary information. In accordance with another aspect of the method, an extensible conductive loop (14) is disposed in close encircling relation about the head such that the plane defined by the loop extends through the mouth. By providing a signal indicative of changes in the inductance of the loop, qualitative and quantitative information for mouth volume may be obtained.

Abstract: A method of semiquantitatively measuring a subject's neck volume includes the steps of providing an extensible conductor in the form of a loop having a predetermined height; providing a signal variably responsive in value to changes in the inductance of the conductor; calibrating the signal by determining reference signal values obtained with the conductor disposed about at least two known volumes and using the reference signal values to establish the relationship between signal value and the volume enclosed by the conductor; disposing the conductor in close encircling relationship about the subject's neck; calibrating the signal for intrapleural pressure by using an invasive technique as a reference for determining a plurality of intrapleural pressures for the subject and simultaneously determining the signal value for each such intrapleural pressure measurment, thereby establishing the relationship between intrapleural pressure and signal value; discontinuing the reference technique; determining the signal

Abstract: A method for monitoring cardiopulmonary events is disclosed. The basic method comprises looping an extensible conductor (14) in close encircling relation about the neck (12) of the subject (10), providing a signal indicative of the inductance of the loop, and monitoring the signal. This signal contains both qualitative and quantitative cardiopulmonary information. In accordance with another aspect of the method, an extensible conductive loop (14) is disposed in close encircling relation about the head such that the plane defined by the loop extends through the mouth. By providing a signal indicative of changes in the inductance of the loop, qualitative and quantitative information for mouth volume may be obtained.

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.

Abstract: A device for measuring a predetermined respiratory volume comprises an elongate, air-tight flexible bag of the predetermined volume, the bag being closed at one end and open at the other; and an elongate substantially rigid tubular member extending into the bag through its open end and occupying a major portion of the length of the bag, the bag being secured at its open end to the tubular member for forming an air-tight seal between the bag and the tubular member, the portion of the tubular member extending into the bag having a plurality of distributed apertures along its length and the portion of the tubular member outside the bag having at least one opening defining a mouthpiece.

Abstract: A method and apparatus are shown for monitoring respiration volumes by continuously measuring, while the patient breathes, variations in the patient's chest cross sectional area, or preferably, variations in both chest and abdomen areas. Each area is measured by measuring the inductance of an extensible electrical conductor closely looped around the body, by connecting the loop as the inductance in a variable frequency LC oscillator followed by a frequency-to-voltage converter and a voltage display. Calibration is made by measuring the area variations for a few breaths while directly measuring corresponding volumes of breath, preferably while the patient assumes at least two body positions, for example sitting and supine. The method and apparatus may also be used to monitor changes in area of any non-magnetic object.