Respiration measurements and dosimetry control in inhalation testing systems

Abstract

Inhalation measurement systems and methods enable, during inhalant exposure, substantially real-time respiratory measurements of a test subject using techniques that obtain measurements of respiration directly from that test subject, instead of from inhalation chamber parameter measurements. Direct test subject respiratory measurements may be, by way of example only, impedance measurements. These respiratory measurements taken directly from the test subject may be transmitted, wirelessly for example, for processing during the course of the test to a processing system to determine a cumulative volume of inhalant inspired by the test subject. From that, a cumulative amount of inhalant (or dose) inspired by the test subject may be determined during the course of the inhalation compound test. In addition, a calibration procedure may be performed before the inhalant exposure to provide correlation needed to translate chest and/or abdominal wall expansion measurements, made during the test, into lung volume measurements.

1 - 21 . (canceled) 
     
     
         22 . A method of performing an inhalation test on a subject during which inhalation test the test subject is at least partially confined within a test chamber and an inhalant substance is introduced into the test chamber, the method comprising:
 collecting during the course of the inhalation test respiration-related measurements for respiration cycles of the test subject using the sensing device applied directly to the test subject; and   timing inhalant concentration changes to a particular phase within a respiratory cycle.   
     
     
         23 . The method of  claim 26 , wherein the respiratory inhalation test further comprises:
 determining, from the respiratory pattern of the test subject, whether a particle size of the inhalant needs to be modified; and   modifying the inhalant particle size in accordance with the determination.   
     
     
         24 . The method of  claim 22 , wherein the respiratory inhalation test further comprises determining, from the position in time within the respiratory cycle of the test subject, the need to modify inhalant concentration, and modifying the inhalant concentration in accordance with the determination. 
     
     
         25 . The method of  claim 22 , wherein the sensing device applied directly to the test subject comprises a monitoring system comprising electrodes positioned to make impedance measurements across or around a portion of the lungs of the test subject. 
     
     
         26 . The method of  claim 22 , wherein the respiratory inhalation test further comprises:
 assessing a respiratory pattern of the test subject; and   adjusting inhalant particle size based on the respiratory pattern.   
     
     
         27 . The method of  claim 22 , further comprising performing a calibration procedure comprising a) collecting respiration-related measurements for each of multiple respiration cycles from the test subject using a sensing device applied directly to the test subject, b) collecting corresponding respiration volume measurements for each of the multiple respiration cycles of the test subject by sensing atmospheric changes of a volume within the test chamber, and c) using the collected respiration-related and respiration volume measurements to calculate a calibration formula that correlates respiration-related measurements collected using the sensing device applied directly to the test subject to respiration volume measurements. 
     
     
         28 . The method of  claim 22 , further comprising:
 determining during the course of the inhalation test a running measure of cumulative dosage of inhalant substance inspired by the test subject; and,   calculating for each respiration cycle a dosage inspired for that cycle using a respiration volume measurement for that cycle, and summing calculated dosage measurements for each cycle to provide the running measure of the cumulative dosage inspired.   
     
     
         29 . The method of  claim 28 , wherein the performing of the inhalation test further comprises:
 comparing the running measure of cumulative respiration volume to a selected threshold value; and   triggering a predefined action to occur if the running measure of cumulative respiration volume reaches the selected threshold value.   
     
     
         30 . A method of performing an inhalation test on a subject during which inhalation test the test subject is at least partially confined within a test chamber and an inhalant substance is introduced into the test chamber, the method comprising:
 collecting respiration-related measurements for respiration cycles of the test subject using the sensing device applied directly to the test subject; and   timing inhalant concentration changes to a particular phase within a respiratory cycle.   
     
     
         31 . The method of  claim 30 , wherein collecting test respiration-related measurements for respiration cycles of the test subject using the sensing device applied directly to the test subject comprises collecting during the course of the inhalation test respiration-related measurements for respiration cycles of the test subject using the sensing device applied directly to the test subject. 
     
     
         32 . The method of  claim 30 , wherein the respiratory inhalation test further comprises determining, from the position in time within the respiratory cycle of the test subject, the need to modify inhalant concentration, and modifying the inhalant concentration in accordance with the determination. 
     
     
         33 . The method of  claim 30  further comprising assessing a respiratory pattern of the test subject, and wherein adjusting inhalant particle size is based on the respiratory pattern. 
     
     
         34 . The method of  claim 33 , wherein the respiratory inhalation test further comprises determining, from the respiratory pattern of the test subject, whether a particle size of the inhalant needs to be modified, and modifying the inhalant particle size in accordance with the determination. 
     
     
         35 . The method of  claim 30 , further comprising adjusting inhalant particle size. 
     
     
         36 . The method of  claim 30 , further comprising performing a calibration procedure comprising a) collecting respiration-related measurements for each of multiple respiration cycles from the test subject using a sensing device applied directly to the test subject, b) collecting corresponding respiration volume measurements for each of the multiple respiration cycles of the test subject by sensing atmospheric changes of a volume within the test chamber, and c) using the collected respiration-related and respiration volume measurements to calculate a calibration formula that correlates respiration-related measurements collected using the sensing device applied directly to the test subject to respiration volume measurements. 
     
     
         37 . The method of  claim 30 , further comprising:
 determining during the course of the inhalation test a running measure of cumulative dosage of inhalant substance inspired by the test subject; and,   calculating for each respiration cycle a dosage inspired for that cycle using a respiration volume measurement for that cycle, and summing calculated dosage measurements for each cycle to provide the running measure of the cumulative dosage inspired.   
     
     
         38 . The method of  claim 30 , wherein the performing of the inhalation test further comprises:
 comparing the running measure of cumulative respiration volume to a selected threshold value; and   triggering a predefined action to occur if the running measure of cumulative respiration volume reaches the selected threshold value.   
     
     
         39 . A monitoring system for use during an inhalation test on a test subject, the monitoring system comprising a test procedure processing module programmed to a) collect during the course of the inhalation test respiration-related measurements for respiration cycles of the test subject using the sensing device applied directly to the test subject, and b) time inhalant concentration changes to a particular phase within a respiratory cycle. 
     
     
         40 . The monitoring system of  claim 39 , wherein the test procedure processing module is further programmed to c) assess a respiratory pattern of the test subject, and d) adjust inhalant particle size based on the respiratory pattern. 
     
     
         41 . The monitoring system of  claim 39 , wherein the respiratory inhalation test further comprises determining, from the position in time within the respiratory cycle of the test subject, the need to modify inhalant concentration, and modifying the inhalant concentration in accordance with the determination. 
     
     
         42 . The monitoring system of  claim 39 , wherein the sensing device applied directly to the test subject comprises a monitoring system comprising electrodes positioned to make impedance measurements across or around a portion of the lungs of the test subject. 
     
     
         43 . The monitoring system of  claim 39 , wherein the sensing device applied directly to the test subject is implanted within the test subject and comprises:
 electrodes positioned to make impedance measurements across or around a portion of the lungs of the test subject; and   a wireless transmitter to transmit the collected respiration-related measurements to external processing equipment.   
     
     
         44 . The monitoring system of  claim 39 , wherein the sensing device applied directly to the test subject is worn by the test subject, and comprises:
 electrodes positioned on the test subject to make impedance measurements across or around a portion of the lungs of the test subject; and   a wireless transmitter to transmit the collected respiration-related measurements to external processing equipment.   
     
     
         45 . The monitoring system of  claim 39 , wherein the sensing device applied directly to the test subject is worn by the test subject, and comprises:
 elastic bands positioned on the test subject to make expansion measurements across a portion of the lungs or abdomen of the test subject; and   a wireless transmitter to transmit the collected respiration-related measurements to external processing equipment.