Assay of Resuscitation Procedures

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Abstract
An assay of resuscitating procedures has been designed. The method depends upon demonstrating the threshold of death for each procedure and then comparing the loci of the several thresholds in the process of death. The threshold of death is shown to be experimentally and sharply definable: it is the last point during the terminal decline of systolic blood pressure at which a given resuscitating procedure uniformly succeeds. Dogs breathing N2 were used for the tests. A positive and negative pressure respiratory pump was found to be 11 sec. superior to periodic O2 insufflation, the margin of superiority residing in the fact that it uniformly succeeds in resuscitating at a point 11 sec. later in the process of death. Similarly, the "suck-and-blow" pump is 3 sec. superior to insufflation with 5% CO2 in O2. CO2 at a 15% level is not superior to any of the above. Manual artificial respiration succeeded in only 19% of trials, the cause for its inadequacy being its failure to ventilate the lungs with even the minimum requirement of air. Attempted resuscitation of dogs by the Eve (tilt-board) method also fails in a large fraction of cases. The differences shown for the 3 methods involving insufflation are so small that for practical purposes all 3 may be considered equal in efficacy. In turn, even minimal quantities of O2, as with a single O2 insufflation or insufflation with 2% O2 in N2, are equal in efficacy to all other insufflation procedures. These data reinforce the conclusion that the critical need in resuscitation is O2 and that the method of giving it is immaterial, providing that it gets into the lungs. The data also demonstrate that the amt. of blood circulated by the positive and negative pressure respiratory pumps is too small to be of any practical importance in resuscitation.