Abstract
Electrocardiographic changes due to acute CO poisoning and those under the influences of the fluid infusion were observed in rabbits.
1) The progresses of CO-Hb level during and after the inhalation of CO gas were similar to those reported by previous investigators. The CO-Hb level never reached the saturation value. The drop of CO-Hb level for the first 30 minutes after the cessation of gas inhalation was more prompt in the animals poisoned with the gas inhalation for a shorter duration than in those for a longer duration.
2) The changes of E. C. G. during the gas inhalation were observed in twelve animals out of twenty. The changes were elevation or depression of the S-T segment and coronary, tent or flat T wave. There was no intimate correlation between the degree of E. C. G. changes and the CO-Hb level. The author infers that it may require a definite time duration, for which high concentration of CO-Hb level is maintained, to produce the changes in E. C. G.
3) Microscopic changes resemble those reported by many authors. Those changes were observed in the animals which did not show the changes in E. C. G.
4) Changes in E. C. G. during the gas inhalation disappeared soon after the cessation of gas inhalation and the E. C. G. returned back to normal after 24 hours. The acutely poisoned animals were infused Ringer-Locke solution added 12% bovine hemoglobin 24, 48 or 96 hours later. The disorders of E. C. G., namely, extrasystoles, remarkable displacement of the S-T segment or A-V block, appeared by the infusion. It is conceivable that the disturbances induced by CO poisoning remained as latent, although the changes of E. C. G. caused by gas inhalation returned to normal and that weakened hearts were unable to bear the burden of the infusion. Thus the cardiac damages must have become manifest.
