US 10,376,663 B2
Method and system for quantifying timing discrepancies between inspiratory effort and ventilatory assist
Christer Sinderby, Toronto (CA); Norman Comtois, Scarborough (CA); Jennifer Beck, Toronto (CA); Pär Emtell, Vällingby (SE); and Michael Kock, Akersberga (SE)
Assigned to St. Michael's Hospital, Toronto (CA)
Appl. No. 14/355,777
Filed by St. Michael's Hospital, Toronto (CA)
PCT Filed Nov. 16, 2012, PCT No. PCT/CA2012/001043
§ 371(c)(1), (2) Date May 1, 2014,
PCT Pub. No. WO2013/071404, PCT Pub. Date May 23, 2013.
Claims priority of provisional application 61/560,600, filed on Nov. 16, 2011.
Prior Publication US 2014/0296728 A1, Oct. 2, 2014
Int. Cl. A61M 16/00 (2006.01); A61B 5/08 (2006.01); A61B 5/0488 (2006.01); A61B 5/04 (2006.01); A61B 5/00 (2006.01)
CPC A61M 16/0051 (2013.01) [A61B 5/04001 (2013.01); A61B 5/04884 (2013.01); A61B 5/08 (2013.01); A61B 5/0809 (2013.01); A61B 5/742 (2013.01); A61M 16/00 (2013.01); A61M 16/0069 (2014.02); A61M 2016/0021 (2013.01); A61M 2205/502 (2013.01); A61M 2210/1014 (2013.01); A61M 2230/40 (2013.01); A61M 2230/60 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method of adjusting a ventilatory support system based on timing discrepancies between a patient's inspiratory effort and ventilatory assist to the patient, comprising:
receiving, at the ventilatory support system, from one or more electrodes, a neural inspiration signal representing an inspiratory effort of the patient;
receiving, at the ventilatory support system, from a mechanical ventilator providing the ventilatory assist to the patient, a measurement signal representing a start time and an end time of the ventilatory assist;
determining, based on the neural inspiration signal, a trigger error by comparing a start time of a current inspiratory effort of the patient with the start time of the ventilatory assist, wherein determining the trigger error comprises ignoring any inspiratory effort in which, between the start time and the end time of the inspiratory effort, a variation of the neural inspiration signal is less than a minimum signal variation threshold, wherein the trigger error is determined based on analysis of the neural inspiration signal and of the measurement signal between an end of a previous inspiratory effort of the patient and an end of the current inspiratory effort of the patient, wherein the start time of the ventilatory assist preceding the start time of the current inspiratory effort of the patient denotes an early trigger error and wherein the start time of the ventilatory assist following the start time of the current inspiratory effort of the patient denotes a late trigger error;
determining, based on the neural inspiration signal, a cycling-off error by comparing an end time of the current inspiratory effort of the patient with the end time of the ventilatory assist, wherein determining the cycling-off error comprises ignoring any inspiratory effort in which, between the start time and end time of the ventilatory assist, a variation of a pressure delivered by the ventilatory assist is less than a minimum pressure variation threshold, wherein the cycling-off error is determined based on analysis of the neural inspiration signal and of the measurement signal between a start of the current inspiratory effort of the patient and a start of a next inspiratory effort of the patient, wherein the end time of the ventilatory assist preceding the end time of the current inspiratory effort of the patient denotes an early cycling-off error and wherein the end time of the ventilatory assist following the end time of the current inspiratory effort of the patient denotes a late cycling-off error; and
adjusting the ventilatory assist provided to the patient by the mechanical ventilator so that the trigger error is lower than a first threshold and the cycling-off error is lower than a second threshold.