A versatile mechanical ventilator (DIGIT) with high flow stability and a programmable inspiratory phase flow pattern

Describes the general characteristics of a newly developed nonconstant-flow generator for automatic ventilation of the lungs. It is known that the application of very high pressure to high internal resistance leads to a very stable flow, in that the flow itself is unaffected by external load (patient) variations. The stability of the flow means that the inspiratory process can be controlled by means of the ventilated volume, thus extending DIGIT utilization to high resistance patients. The modulation of the flow is implemented via a digital electromechanical system, which allows the ventilator functions to be accurately programmed. The desired flow waveform is obtained by means of a series of pneumatic valves, the apertures of which are digitally controlled. The design is innovative in that it allows the flow waveform in each of the ten digitalized time steps into which each inspiratory phase is divided to be both programmed and controlled. Other ventilators commercially available and currently in use do not have this functional capability, as they are all designed to model the integral flow of the inspiratory waveform without being able to modify the subunit time steps of a single inspiratory phase. The authors also discuss the results of fundamental tests concerning the performance characteristics of the ventilator.

[1]  R. Chatburn,et al.  Mechanical ventilators optimized for pediatric use decrease work of breathing and oxygen consumption during pressure‐support ventilation , 1994, Critical care medicine.

[2]  Arthur T. Johnson,et al.  Relation Between Limiting Exhalation Flow Rate and Lung Volume , 1987, IEEE Transactions on Biomedical Engineering.

[3]  A. Johnson,et al.  A new ventilator converter with the Siemens Servo Ventilator ‐ evaluation in a lung model , 1992, Acta anaesthesiologica Scandinavica.

[4]  P E Pepe,et al.  Occult positive end-expiratory pressure in mechanically ventilated patients with airflow obstruction: the auto-PEEP effect. , 1982, The American review of respiratory disease.

[5]  Gerald M. Saidel,et al.  Estimation of Mechanical Parameters in Multicompartment Models Applied to Normal and Obstructed Lungs During Tidal Breathing , 1986, IEEE Transactions on Biomedical Engineering.

[6]  Susan A. Ward,et al.  A Device to Provide Respiratory-Mechanical Unloading , 1986, IEEE Transactions on Biomedical Engineering.

[7]  Renzetti Ad,et al.  Mechanical behavior of the respiratory system as a function of frequency in health and disease. , 1983 .

[8]  D. Cox,et al.  Investigation of the spontaneous modes of breathing of different ventilators , 1988, Intensive Care Medicine.

[9]  J. Venegas.  Equivalent Circuit Analysis of High-Frequency Ventilators Including a New High-Impedance Flow-Interrupting Ventilator , 1986, IEEE Transactions on Biomedical Engineering.

[10]  Denis E. O'Donnell,et al.  Clinical Respiratory Physiology , 2019, Clinics in Chest Medicine.

[11]  Benjamin Bach,et al.  Etude de 11 ventilateurs d'anesthésie : banc d'essai , 1992, Annales Françaises d'Anesthésie et de Réanimation.

[12]  W. Kox,et al.  Effect of weaning on oxygen consumption and cardiovascular function A comparison of continuous flow and demand valve systems , 1994, Anaesthesia.

[13]  William Woolf Mushin,et al.  Automatic ventilation of the lungs , 1969 .

[14]  D. Hill,et al.  THE ACTION OF ADIABATIC EFFECTS ON THE COMPLIANCE OF AN ARTIFICIAL THORAX. , 1965, British journal of anaesthesia.

[15]  A. Baker,et al.  Towards a Better Classification of Lung Ventilators , 1974, Anaesthesia and intensive care.

[16]  B.A. Simon,et al.  Design and calibration of a high-frequency oscillatory ventilator , 1991, IEEE Transactions on Biomedical Engineering.

[17]  K. Lutchen,et al.  Human respiratory input impedance from 4 to 200 Hz: physiological and modeling considerations. , 1988, Journal of applied physiology.

[18]  A. Johnson,et al.  Comparison of anaesthesia ventilators using a lung model , 1990, Acta anaesthesiologica Scandinavica.

[19]  A S Slutsky,et al.  Factors inducing periodic breathing in humans: a general model. , 1982, Journal of applied physiology: respiratory, environmental and exercise physiology.

[20]  S. P. McPherson,et al.  Respiratory therapy equipment , 1977 .

[21]  R. A. Epstein,et al.  A new ventilator for physiologic studies during high-frequency ventilation. , 1982, Respiration Physiology.

[22]  H J Bender,et al.  [The performance of respirator alarms during simulated critical events in CMV/IPPV artificial respiration]. , 1993, Der Anaesthesist.

[23]  G. Heldt,et al.  Response time and reliability of three neonatal patient-triggered ventilators. , 1993, The American review of respiratory disease.