Determining patient-ventilator breath contribution index in spontaneously breathing, mechanically ventilated patients
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Publication Number
US-8720441-B2
Publication Date
2014-05-13
Expiration Date
Abstract
The present invention relates to a system and method for determining a patient-ventilator breath contribution index in a spontaneously breathing, mechanically ventilated patient. A patient's efficiency to generate an inspiratory volume without mechanical ventilatory assist and a patient's efficiency to generate an inspiratory volume with mechanical ventilatory assist are calculated and used to determine the patient-ventilator breath contribution index.
Core Innovation
The invention determines a patient-ventilator breath contribution index in a spontaneously breathing, mechanically ventilated patient. It characterizes how much of the patient’s inspiratory volume is generated by the patient versus the mechanical ventilatory assist using diaphragm electrical activity and inspiratory volume.
The method measures electrical activity and inspiratory volume during inspiration in two conditions: without mechanical ventilatory assist and with mechanical ventilatory assist. For each condition, it calculates a patient's efficiency to generate an inspiratory volume as a ratio between inspiratory volume and electrical activity.
The patient-ventilator breath contribution index is then calculated as a third ratio comparing the two calculated efficiencies, expressed as the efficiency ratio without mechanical ventilatory assist divided by the efficiency ratio with mechanical ventilatory assist. The disclosed system uses detectors to sense electrical activity of the respiratory muscle during inspiration and to detect inspiratory volume, and includes a calculator configured to compute the first and second efficiency ratios and the patient-ventilator breath contribution index.
Claims Coverage
Two independent claims cover a method and a system for determining a patient-ventilator breath contribution index using measured signals in without- and with-mechanical-ventilatory-assist conditions and combining them via first, second, and third ratios.
Determining PVBC by efficiency ratios from respiratory muscle electrical activity and inspiratory volume without and with ventilatory assist
Measuring electrical activity of a patient's respiratory muscle during inspiration without mechanical ventilatory assist and with mechanical ventilatory assist; measuring inspiratory volume without and with mechanical ventilatory assist; calculating a patient's efficiency to generate an inspiratory volume without mechanical ventilatory assist as a first ratio between inspiratory volume and electrical activity; calculating a patient's efficiency with mechanical ventilatory assist as a second ratio between inspiratory volume and electrical activity; and calculating the patient-ventilator breath contribution index as a third ratio between the calculated efficiencies.
PVBC determination using first and second detectors and a calculator combining first, second, and third ratios
A system comprising a first detector of electrical activity of a patient's respiratory muscle during inspiration without mechanical ventilatory assist and with mechanical ventilatory assist; a second detector of a patient's inspiratory volume without mechanical ventilatory assist and with mechanical ventilatory assist; and a calculator determining a patient's efficiency without mechanical ventilatory assist as a first ratio between detected inspiratory volume and detected electrical activity, determining a patient's efficiency with mechanical ventilatory assist as a second ratio between detected inspiratory volume and detected electrical activity, and determining the patient-ventilator breath contribution index as a third ratio between the calculated efficiencies.
Across both independent claims, the central coverage is the same: determine PVBC by computing a first and second efficiency ratio from respiratory muscle electrical activity and inspiratory volume measured without versus with mechanical ventilatory assist, and combine the two efficiencies into a third ratio defining the patient-ventilator breath contribution index.
Stated Advantages
Documented Applications
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