Method and system for adjusting a level of ventilatory assist to a patient
Inventors
Sinderby, Christer • Beck, Jennifer • Comtois, Norman • Jalde, Fredrik
Assignees
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Publication Number
US-10758693-B2
Publication Date
2020-09-01
Expiration Date
Abstract
The present disclosure relates to a method and a mechanical ventilation system for adjusting a level of ventilatory assist to a patient. A neuro-mechanical efficiency of the patient is determined. A control value is received at the mechanical ventilation system. The level of ventilatory assist to the patient is determined on the basis of the neuro-mechanical efficiency and of the control value. The mechanical ventilation system may be adjusted automatically based on the determined level of ventilatory assist to the patient. Alternatively, the determined level of ventilatory assist to the patient may be displayed for the benefit of an operator and a manual command may be received for adjusting the mechanical ventilation system.
Core Innovation
The invention relates to a mechanical ventilation method and system that adjusts a level of ventilatory assist (ASSIST) for a patient by using a neuro-mechanical efficiency (NME) computed from synchronized measurements. The approach measures electrical activity (EAmsi, EAmsiocc) of a patient's respiratory muscle synchronized with an inspiratory effort and determines NME based at least in part on a ratio of a respiratory volume or pressure induced by the patient's respiratory muscle over the measured electrical activity (EAmsi) of the patient's respiratory muscle.
In one implementation, a control value is received that is selected from a desired unloading level (UL) for the patient and/or an operator setting for a target tidal volume (Vt_tgt) for the patient. A relation between the desired unloading level (UL) and the target tidal volume (Vt_tgt) is defined for a nominal tidal volume (VtPBW) determined based on a predicted body weight of the patient, and the system determines the ventilatory assist level (ASSIST) based on the control value and the neuro-mechanical efficiency (NME).
The document also describes an inspiratory occlusion-based determination of NME, using an inspiratory occlusion associated with an inspiratory effort, with a detector calculating NME at least in part as a ratio of airway pressure variation during the inspiratory occlusion (ΔPawocc) over the synchronized respiratory muscle electrical activity during the inspiratory occlusion (EAmsiocc). Further, the system can include a cardiac signal extractor to remove cardiac signal components from a measured electrical activity signal to produce a respiratory muscle electrical activity signal synchronized with inspiratory effort, and a controller responsive to the operator interface and to the detector to determine ASSIST.
Claims Coverage
The partial content includes four independent claims, covering (i) an ASSIST adjustment method in a mechanical ventilation system, (ii) an ASSIST adjustment mechanical ventilation system architecture, (iii) a method for determining weaning readiness, and (iv) a mechanical ventilation system for weaning readiness determination. Across these independent claims, the document defines NME-based assist determination and a wean index based on predicted body weight and target respiratory muscle electrical activity.
Neuro-mechanical efficiency based assist adjustment from synchronized respiratory muscle electrical activity and induced pressure/volume
A method for adjusting ventilatory assist (ASSIST) to a patient that receives a control value selected from a desired unloading level (UL) and an operator setting for a target tidal volume (Vt_tgt), measures electrical activity (EAmsi, EAmsiocc) of a patient's respiratory muscle synchronized with an inspiratory effort, determines a neuro-mechanical efficiency (NME) calculated at least in part based on a ratio of a respiratory volume or pressure induced by the patient's respiratory muscle over the measured electrical activity (EAmsi), and determines the level of ventilatory assist (ASSIST) based on the neuro-mechanical efficiency (NME) and the desired unloading level (UL).
Unloading level and target tidal volume relation using predicted body weight derived nominal tidal volume
The method further includes defining a relation between a desired unloading level (UL) and a target tidal volume (Vt_tgt), for a nominal tidal volume (VtPBW) determined based on a predicted body weight of the patient, where UL=(VtPBW−Vt_tgt)/VtPBW.
Neuro-mechanical efficiency based assist adjustment using an architecture with an electrical activity sensor, a detector, and a controller
A mechanical ventilation system with an operator interface adapted to receive a control value selected from a desired unloading level (UL) and an operator setting for a target tidal volume (Vt_tgt), an electrical activity sensor adapted to measure electrical activity (EAmsi, EAmsiocc) synchronized with an inspiratory effort, a detector of neuro-mechanical efficiency (NME) calculated at least in part based on a ratio of a respiratory volume or pressure induced by the patient's respiratory muscle over the measured electrical activity (EAmsi), and a controller that determines the level of ventilatory assist (ASSIST) on the basis of the NME and the desired unloading level (UL).
Weaning readiness determination using target respiratory muscle electrical activity, measured unassisted inspiratory volume and electrical activity, and a wean index based on predicted body weight
A method for determining whether a patient is ready to be weaned that receives a control value representing a target electrical activity (EAmsi_tgt) of a respiratory muscle synchronized with inspiratory effort for a normally breathing patient, measures an inspiratory volume (Vt) during an unassisted inspiration, measures synchronized electrical activity (EAmsi) during the unassisted inspiration, determines a nominal tidal volume (VtPBW) based on predicted body weight, estimates an expected tidal volume for the normally breathing patient using VtEAmsi_tgt=EAmsi_tgt·VtEAmsi, calculates a wean index (WEAN_index)=VtEAmsi_tgt/VtPBW, and determines whether the patient is ready to be weaned as a function of a value of the WEAN_index.
Weaning readiness determination system using a flow meter, an electrical activity sensor, and a controller configured to compute expected tidal volume and wean index
A mechanical ventilation system comprising an operator interface adapted to receive a target electrical activity (EAmsi_tgt) synchronized with inspiratory effort, a flow meter to measure an inspiratory volume (Vt) during an unassisted inspiration, an electrical activity sensor to measure synchronized electrical activity (EAmsi) during the unassisted inspiration, and a controller configured to determine nominal tidal volume (VtPBW) based on predicted body weight, estimate expected tidal volume using VtEAmsi_tgt=EAmsi_tgt·VtEAmsi, calculate wean index (WEAN_index)=VtEAmsi_tgt/VtPBW, and determine whether the patient is ready to be weaned as a function of a value of the wean index.
Across the independent claims, the core coverage centers on computing neuro-mechanical efficiency (NME) from synchronized respiratory muscle electrical activity and induced respiratory volume/pressure, using unloading level or target tidal volume relations, and computing a wean index (WEAN_index) from predicted body weight, a target respiratory muscle electrical activity, and unassisted inspiration measurements to determine weaning readiness.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Determining whether a patient is ready to be weaned from the mechanical ventilation system.
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