GB723213A - Improvements in and relating to electric stimulation of respiration - Google Patents

Abstract

723,213. Electromedical apparatus. HOFMANN, W. June 13, 1951 [June 13, 1950], No. 13973/51. Class 81 (2). Apparatus for the electrical stimulation of respiration comprises two separate electrode circuits, each circuit having means for connecting a pair of electrodes across it, a control circuit for the electrode circuits containing a reversible switch movable between inspiration and expiration positions, a timing device for closing the switch alternately in breathing rhythm in one or other of its closed positions. A pair of inspiration inducing electrodes 13, 14 are connected across terminals N-10, I-10 in an inspiration circuit 10 including a valve 11 and an indicator 12. Another pair of electrodes 23, 24 are similarly connected across terminals N-20, E-20 in a circuit 20 including a valve 21 and an indicator 22 and are' used to induce expiration. The grids of the valves 11, 21 in control circuits 40, 50 respectively are connected through resistances and a reversible switch r-2 so that the valves 11, 21 conduct alternately and current flows alternately across inspiration electrodes 13, 14 or expiration electrodes 23, 24, another switch r-1 in the electrode circuits 10, 20 reversing synchronously with the reversible switch r-2. A change-over switch contact also in the electrode circuits 10, 20 alternates between contacts 35, 36 at a frequency which may be adjusted to alternately connect a condenser 37 across a D.C. voltage of 300 volts and in the anode circuits of the valves 11, 21 so that the pulses flowing across the electrodes due to the operation of either valve 11, 21 are broken into short impulses of the same frequency as the change-over switch. The valve control circuits' 40, 50 are earthed through a switch s-1. The reversible switches r-1, r-2 and the earthing switch s-1 are operated by relays in an electric timing device (not shown). Elements in the timing device are adjustable so that inspiration and expiration pulses are applied to the body in a predetermined breathing rhythm. The apparatus may be modified by connecting electrodes across other terminals E-10, 1-20 in the inspiration and expiration circuits 10, 20 respectively so that pulses are applied to the .body to produce either expiration alone or inspiration alone. An inspiration electrode 13, Fig. 3, is in the form of a band which half encircles the body and is joined to a similar electrode 14 by insulation 15, 16 to completely encircle the body. Leads 13a, 14a connect the electrodes to the electrode circuit 10. Inspiration-producing currents 17 pass across the body transversely. Expiration electrodes 23, 24 are each in the form of bands which encircle the body and are spaced from one another. The expiration-producing currents 27 traverse the body longitudinally.