l:y the of an inhaler, which is ••11. letely open at the top and into -1.i••11 tlie gas is allowed to fall by at heric pressure, from the end of a p•y-pipe I eld over it. the full am-es tl ..tie clreets of the gas eau fie obtained. 1.1 • Aministration of the ana,.sthetie .oay Le continued for eleven minutes, itl,,mt any disturbance of pulse or res iration. Neither have any subsequent ill etTe,t, been observed. George Flux Lancet. Feb. 4. '99).
Nitrous Oxide and Oxygen.—Practical anti general results of '11'-; with nitrous oxide on animals 1 :e :,hoNvn that it is possible to ,et a re of oxy,,zen and nitrous oxide which will contain sufficient oxygen to maintain for a length of time the vital function, and yet have so little oxygen that consciousness would be lost. The experiments of -Wood have shown that in the dog 6 per cent. of oxygen in the nitrous oxide is probably the nearest ap proach to a practical anmsthetic mixture that can be made. Although theoretical evidence has suggested that nitrous oxide acts merely by shutting off oxygen from the blood, clinical evidence would seem to prove that the ansthetic effect is preserved when oxygen is adminis tered concomitantly and that safety is still further insured.
F. N. Hewett and others affirm that the combined use of nitrous oxide and oxygen is the safest method of amesthe tizing at present known, and the unpleas ant after-effects of antEstheFia may usu ally be avoided when it is employed; but the anmsthesia induced is not so deep as that produced by ether or chloroform, the muscular system is not so completely re laxed, and is not always possible to pre vent reflex and other movements during, administration. The best results with nitrous oxide and ether have been with children and weak women. Strong, vig orous male adults, especially drinkers or excessive smokers, are bad subjects. It is important to avoid the ingestion of solids and fluids for several hours after the administration of this agent.
Nitrous-oxide amesthesia ean be main tained for long operations, with perfect safety to the patient, if it is combined with oxygen. When ordinary air is di
luted with it the patient is partially asphyxiated and occasional suspension of the amesthesia is necessary. The re sult is that prolong.ed amosthesia with such a mixttre means that it is a mere succession of asphyxiations. A mixture of nitrous oxide and 10 per cent. of oxy gen prodnees no asphyxia. \Vida shows that nitrous oxide has pore ana.sthetic properties. A Y-shaped pipe connected with the nose and mouth and containing a valve by which the amount of oxygen in proportion to the nitrous oxide ean be accurately regulated subtnitted, be sides a review of one hundred narcoses in whieh the aniesthesia lasted more than one-half hour—three more than two hours. S. O. Gohlan (Amer. ,Tour. :Med. Sei., June, 1901).
The great advantage in the use of oxygen in connection with nitrous oxide is that a longer and more profound an testhesia is obtained, free from cyanosis and anoxretnie convulsion. The anaes thetic does not have the disagreeable sweet taste and the suffocating sensa tion so objectionable to the patient in the first stage of pure nitrous-oxide an a•sthesia. There is also an advantage in the use of oxygen with nitrous oxide over the use of air as the oxygenating agent. If an admixture of air and nitrous oxide containing more than 6 per cent. of oxygen is used, complete aniesthesia cannot be produced, because the percentage of nitrous oxide (being about 00 per cent.) is not great enough to produce the desired result. It is often necessary to increase the percentage of oxygen in a mixture of nitrous oxide and oxygen to 8, 10. or even 15 per cent. to obtain the desired freedom from as phyxial manifestations. Personal habit is to give the patient about 2 or 3 per cent. of oxygen approximately and in , crease to 7, 8, or 10 per cent., according as the patient requires. J. F. Stephan (Cleveland Jour. of Afed., Sept.. 1901).