Method and device for determining a level of ventilatory assist to a patient
Inventors
Sinderby, Christer • Beck, Jennifer
Assignees
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Publication Number
US-8881725-B2
Publication Date
2014-11-11
Expiration Date
Abstract
A method and device determine a level of mechanical ventilatory assist to be delivered to a patient. A patient's neural respiratory drive is measured and multiplied by an existing amplification factor to obtain an existing predicted ventilatory pressure. A mechanical ventilator is controlled accordingly. An existing resulting pressure is measured. The patient's neural respiratory drive is multiplied by a modified amplification factor to obtain a new predicted pressure. The existing and new predicted pressures are compared to determine an anticipated change in pressure. The mechanical ventilator is now controlled according to the new predicted pressure. A new resulting pressure is measured. The existing and new resulting pressures are compared to determine an actual change in pressure. The anticipated and actual changes in pressure are compared. The amplification factor is increased, maintained or decreased in response to the comparison between the anticipated and actual changes in pressure.
Core Innovation
The invention relates to determining a level of ventilatory assist to be delivered to a patient by a mechanical ventilator. The method measures a patient's neural respiratory drive and multiplies it by an existing value of an amplification factor to obtain an existing predicted ventilatory assist pressure, and applies a first control signal representative of the existing predicted ventilatory assist pressure to the mechanical ventilator.
The invention modifies the amplification factor to obtain a new value and multiplies the patient's neural respiratory drive by the new amplification factor to obtain a new predicted ventilatory assist pressure. A second control signal representative of the new predicted ventilatory assist pressure is applied, and a new resulting pressure delivered to the patient is measured.
The invention compares the new predicted ventilatory assist pressure and the existing predicted ventilatory assist pressure to determine an anticipated change in pressure, and compares the new resulting pressure and the existing resulting pressure to determine an actual change in pressure delivered to the patient. The anticipated change in pressure is compared with the actual change in pressure, and a decision is delivered to increase, maintain or decrease the amplification factor in response to the comparison.
Claims Coverage
The document includes two independent claims. Both independent claims cover a neural-drive-based ventilatory assist level determination using an amplification factor, and a closed-loop comparison between anticipated and actual delivered pressure changes to decide whether to increase, maintain, or decrease the amplification factor.
Neural respiratory drive amplification to form predicted ventilatory assist pressure and control signals
Measuring a patient's neural respiratory drive; using a calculator to multiply the patient's neural respiratory drive by an existing value of an amplification factor to obtain an existing predicted ventilatory assist pressure; applying a first control signal representative of the existing predicted ventilatory assist pressure to the mechanical ventilator; modifying the amplification factor to obtain a new value; using a calculator to multiply the patient's neural respiratory drive by the new value of the amplification factor to obtain a new predicted ventilatory assist pressure; applying a second control signal representative of the new predicted ventilatory assist pressure to the mechanical ventilator.
Anticipated vs actual pressure change comparison to drive amplification-factor adjustment
Measuring an existing resulting pressure and a new resulting pressure delivered to the patient by the mechanical ventilator; using a first comparator to compare the new predicted ventilatory assist pressure and the existing predicted ventilatory assist pressure to determine an anticipated change in pressure; using a second comparator to compare the new resulting pressure and the existing resulting pressure to determine an actual change in pressure; using a third comparator to compare the anticipated change in pressure with the actual change in pressure; and using a third calculator to deliver a decision to increase, maintain or decrease the amplification factor in response to the comparison.
Across the independent method and device claims, the inventive coverage is directed to forming predicted ventilatory assist pressure from a measured neural respiratory drive via an amplification factor, applying corresponding control signals, measuring resulting pressure for both control signals, comparing anticipated and actual pressure changes, and using that comparison to decide whether to increase, maintain, or decrease the amplification factor.
Stated Advantages
Documented Applications
No documented applications found
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