Event-based delay detection and control of networked systems in medical ventilation
This disclosure describes systems and methods for detecting and quantifying transmission delays associated with distributed sensing and monitoring functions within a ventilatory system. Specifically, the present methods and systems described herein define an event-based delay detection algorithm for determining transmission delays between distributed signal measurement and processing subsystems and a central platform that receives data from these subsystems. It is important to evaluate and quantify transmission delays because dyssynchrony in data communication may result in the misalignment of visualization and monitoring systems or instability in closed-loop control systems. Generally, embodiments described herein seek to quantify transmission delays by selecting a ventilator-based defining event as a temporal baseline and calculating the delay between the inception of the defining event and the receipt of data regarding the defining event from one or more distributed sensing devices.
1. A method implemented by a ventilator system comprising at least one processor and at least one memory, the at least one memory storing computer-readable instructions that when executed by the at least one processor cause the ventilator system to perform a method for determining a transmission delay associated with a distributed sensor in the ventilator system, the method comprising:
initiating, by the ventilator system, a defining event;
receiving a first plurality of data samples for a parameter after inception of the defining event from an internal sensor;
receiving a second plurality of data samples for the parameter after inception of the defining event from a distributed sensor;
indexing the first plurality of data samples in order of successive cycles based on data sample arrival times from the internal sensor;
indexing the second plurality of data samples in order of successive cycles based on data sample arrival times from the distributed sensor;
calculating a first number of cycles received from the internal sensor after inception of the defining event until a first data sample of the first plurality of data samples breaches a threshold associated with the parameter;
calculating a second number of cycles received from the distributed sensor after inception of the defining event until a first data sample of the second plurality of data samples breaches the threshold associated with the parameter;
calculating, by the ventilator system, the transmission delay associated with the distributed sensor by subtracting the first number of cycles from the second number of cycles, wherein the transmission delay is represented as a number of cycles;
synchronizing data received from the internal sensor and the distributed sensor based on the calculated transmission delay associated with the distributed sensor; and
analyzing, by the ventilator system, the synchronized data in order to identify at least one of a leak and an occlusion in a ventilatory circuit.
2. The method of claim 1 , wherein the defining event is a transition from inspiration to expiration.
3. The method of claim 1 , wherein the first plurality of data samples comprises 20 data samples collected over 100 milliseconds (ms) after the inception of the defining event by the internal sensor and the second plurality of data samples comprises 20 data samples collected over 100 milliseconds (ms) after the inception of the defining event by the distributed sensor.
4. The method of claim 1 , wherein the distributed sensor is a proximal flow sensor.
5. The method of claim 1 , wherein the threshold is a circuit pressure change of 0.5 cm H 2 O, and wherein the threshold is breached when a data sample indicates that circuit pressure dropped by 0.5 cm H 2 O or more.
6. The method of claim 1 , further comprising:
initiating a plurality of consecutive defining events comprising a transition from inspiration to expiration for each of a plurality of consecutive breaths.
7. The method of claim 6 , further comprising:
calculating a set of distributed sensor delays, wherein the set of distributed sensor delays comprises a distributed sensor delay for each of the plurality of consecutive defining events; and
calculating a median of the set of distributed sensor delays to yield a distributed sensor delay coefficient.
8. The method of claim 7 , further comprising:
synchronizing the data received from the internal sensor and the distributed sensor based on the distributed sensor delay coefficient.
9. A method implemented by a ventilator system comprising at least one processor and at least one memory, the at least one memory storing computer-readable instructions that when executed by the at least one processor cause the ventilator system to perform a method for determining a transmission delay associated with a distributed sensor in the ventilator system, the method comprising:
initiating, by the ventilator system, a defining event;
receiving a first plurality of data samples for a parameter after inception of the defining event from an internal sensor;
receiving a second plurality of data samples for the parameter after inception of the defining event from a distributed sensor;
indexing the first plurality of data samples in order of successive cycles based on data sample arrival times from the internal sensor;
indexing the second plurality of data samples in order of successive cycles based on data sample arrival times from the distributed sensor;
calculating a first number of cycles received from the internal sensor after inception of the defining event until a first data sample of the first plurality of data samples breaches a threshold associated with the parameter;
calculating a second number of cycles received from the distributed sensor after inception of the defining event until a first data sample of the second plurality of data samples breaches the threshold associated with the parameter;
calculating the transmission delay associated with the distributed sensor by subtracting the first number of cycles from the second number of cycles, wherein the transmission delay is represented as a number of cycles;
synchronizing data received from the internal sensor and the distributed sensor based on the calculated transmission delay associated with the distributed sensor; and
analyzing the synchronized data for making a recommendation regarding at least one of: a patient condition and a patient treatment.
10. The method of claim 9 , further comprising:
initiating a plurality of consecutive defining events comprising a transition from inspiration to expiration for each of a plurality of consecutive breaths.
11. The method of claim 10 , further comprising:
calculating a set of distributed sensor delays, wherein the set of distributed sensor delays comprises a distributed sensor delay for each of the plurality of consecutive defining events; and
calculating a median of the set of distributed sensor delays to yield a distributed sensor delay coefficient.
12. The method of claim 11 , further comprising:
synchronizing the data received from the internal sensor and the distributed sensor based on the distributed sensor delay coefficient.