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HE use of helium as a ther;~pentic gas was first suggested 11~ Barachl in 1934, although in 1923 it had been employed in decnmpressing men working under high gas pressure. The effectiveness of helium is t111ot,o the fact tha,t the density OFthis gas is one-seventh that, of nitrogclt and one-eighth that of oxygen. and that it is an inert gas which cikll r~c~pla.c:c~ t.hc inert nitrogen of air. A mixture of 80 per cent helium and 20 per c,ent oxygen is three limes as light as air, and is, therefore, b~~~usc~of its greater diffusibility mUCt1 more easily breathed. Barach has shown. that such a mixture will pass I hrough obstructed respiratory passagtlsand into collapsed alveoli which arc impenetrable by air. heliunl-oxygen to Ijt: of ljeneftt in the t rr:~.t Lee?, 3 found fnilurc? frequently experienced I,- tha newborn infant:: of believe that t~\cr,v ruhic eentimet.w of nitrogen in air is :I lialbility a.nd that it cm he wplac~tl, at lest. theoretically-, hy helium. After experimen tinf n-ith mixtures of‘ caribous I)ropc)i-Cons. tlwse investigators decidecl that the most diicient combination WYHS SO per cent helium and 20 per cent osvgen. This provides as muth oxygen as is prwent in air, and ii‘ snore orygm ww us+1 it would form :I heavier, less diffusil)le mixture. The benefit, if any, of t,he in(areased wuount. of uxygen u-nulrl lw rrullifird lry 1hc tlncrc~wc i II the prnrtrahilit,s of the mistuw. Benedict, White, and went nf the respiratory diabetic- mothcra. They
In view of the findings of these observers, it secbmedprobable t,hat it helium would carry oxygen into partially ohstructcd air passagesand alveoli of funct,ioning lungs, it. ~~onld act similarly in tht: undilatc?cl lungs of asphyxiated newborn hahies when supplied under prol~trly COILtrolled pressure. In approximately 200 cases. the mixture of X0 per cent helium an11 20 per cent oxygen has been employed. Few of these babies w’crc deeply asphyxiated, some not at all. Because of the belief that, ever>minute of delayed respiration may cause irreparable damage to brain tissue, every infant., immediately after t.he cord is cut, is pli*.eetl in :I respirator and oxygen or helium-oxygen is administered. The ;tpparatus used is the Kreiselman modification of a resuscitator described in 1.928 by ~Kreiselman, Kane and S;~:ope,~which delivers gas to the upper end of the trachea under (dontrolled prc~r~l~!. Several methods of evaluat.ing the incrtlascd efficar,~ of the mist ure over undiluted oxygen have been tried, nom! of which gave: information of value. The experi-
KANE
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ASPHYXIA
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ments by Baritch on human adults who were able to cooperate and on dogs which could be autopsied, could not be duplicated with infants as subjects. Barach’s findings, based upon the study of functioning lungs, show unquestionably that helium-oxygen requires a markedly lower pressure to pass it through partially obstructed passages than do air or oxygen. Barach6 also notes that “with severe obstruction the inspiratory strider is accompanied by a sucking in of the abdominal or chest wall. ” This phenomerion is commonly seen in partially asphyxiated infants. “In the presence of such marked inspiratory obstruction, the secondary development of edema fluid and red corpuscles passing into the alveolar sacs contributes the dangerous factor of severe anoxemia with its reThe sultant damaging effect on the circulatory and respiratory systems. use of helium as a diluent facilitates the entrance of the combined gas and tends to prevent fatigue and paralysis of the respiratory musculature. ’ ’ After respiration has been established, therefore, it is advisable to continue the administration of helium-oxygen until the chest movements denote that breathing requires only normal muscular action. Belief in the clinical value of the 80 per cent helium and 20 per cent oxygen mixture in the resuscitation of the asphyxiated newborn is based wholly upon the observation, perhaps biased, of 200 babies by several of the attending staff, anesthetists, the house staff, delivery room supervisors, and nurses at Garfield Hospital. All agree that in cases of light asphyxia the babies respond much more quickly to the mixture than to pure oxygen. In several cases of deep asphyxia, after oxygen alone had been used without success, the addition of helium was followed by almost immediate clearing of cyanosis and prompt respiratory movements. The author realizes that a theory based upon experiments of others which are not exactly relevant, and upon the clinical observation of a small number of cases is practically unsupported, The suggestion that helium be added to oxygen as a medium for initiating respiration in the asphyxiated newborn is presented, however, in the hope of stimulating further investigation of its value. REFERENCES
(2) Benedict, (1) Barach, 8. L.: Proc. Sot. Exper. Biol. & Med. 32: 462, 1934. F. G., White, P., and Lee, R. C.: AM. J. OBST. & GYNEC. 39: 63, 1940. (3) Idem: (4) E reiselman, Personal communication, 1938. J., Eane, H. F., and Swope, R. W.: AM. J. OBST, & GYNEC. 15: 552, 1928. (5) Barach, A. L.: Ann. Int. Med. 9: 739, 1935. (6) Idem: J. Clin. Investigation 15: 47, 1936. 1835 EYE
STREET, N. W.