METHODS AND APPARATUS FOR THE SYSTEMIC CONTROL OF VENTILATORY SUPPORT IN THE PRESENCE OF RESPIRATORY INSUFFICIENCY
First Claim
1. A method for providing ventilatory assistance to a spontaneously breathing patient comprising continuously repeating the steps of:
- determining respiratory airflow,computing a measure of the difference between a function of respiratory airflow over a period of time and a target value,determining the phase of the current breathing cycle, anddelivering air to the patient at a pressure that is a function of the product of (a) said difference measure, (b) the amplitude at the determined phase of the current breathing cycle of an amplitude-versus-phase template that is appropriate for a normal breathing cycle, and (c) a gain factor that varies depending on the magnitude of said difference measure.
2 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for providing ventilatory assistance to a spontaneously breathing patient an error signal (56) is computed that is the difference between a function of respiratory airflow (54) over a period of time and a target value (52). Using a servo loop, air is delivered to the patient at a pressure that is a function of the error signal, the phase of the current breathing cycle, and a loop gain that varies depending on the magnitude of the error signal. The loop gain increases with the magnitude of the error signal, and the gain is greater for error signals below a ventilation target than for error signals above the ventilation target value. The target value (52) is an alveolar ventilation that takes into account the patient'"'"'s physiologic dead space.
-
Citations
16 Claims
-
1. A method for providing ventilatory assistance to a spontaneously breathing patient comprising continuously repeating the steps of:
-
determining respiratory airflow, computing a measure of the difference between a function of respiratory airflow over a period of time and a target value, determining the phase of the current breathing cycle, and delivering air to the patient at a pressure that is a function of the product of (a) said difference measure, (b) the amplitude at the determined phase of the current breathing cycle of an amplitude-versus-phase template that is appropriate for a normal breathing cycle, and (c) a gain factor that varies depending on the magnitude of said difference measure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. Apparatus for providing ventilator assistance to a spontaneously breathing patient comprising:
-
processing means for computing a measure of the difference between a function of respiratory airflow over a period of time and a target value, and for determining the phase of the current breathy cycle, and a control mechanism for causing a blower to deliver air to the patient at a pressure that is a function of said difference measure, the amplitude at the determined phase of the current breathing cycle of an amplitude-versus-phase template that is appropriate for a normal breathing cycle, and a gain factor that varies depending on the magnitude of said difference measure. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
-
Specification