Document dnX3ggYoo8j7jrpqQgn95pk9

138 CHAPTER 7 1958 Guidffi injuries, those subjected to brain operations, and those, with barbiturate*,^;; poisoning may have hyperthermia, especially in a hot environment, due tolSt-i a disturbance in the heat regulatory center of the brain. Obviously, one ofgjs? the most important factors in recovery is an environment in which theg^i patient can lose heat by radiation and evaporation, namely, a cool roomiy; with dehumidified air: The patient in shock, or the patient who has had a severe hemorrhage, may have an inadequate volume of circulating blood and be unable maintain an adequate skin circulation. This may result in heat storage or fever. Patients with extensive skin bums may be unable to lose heat ;; adequately from the limited uninvolved skin surface, and thus develop ajig. fever. They need adequate fluid replacement, saline solution, plasma or Ti blood to expand the circulating blood volume and thereby improve pe-)l> ripheral circulation. A cool environment is valuable in aiding heat loss;;v after adequate skin circulation is established. A hot, dry environment (89.6 F and 35 percent relative humidity)J>i baa been used over an extended period for the treatment of patients with|j;- rheumatoid arthritis, with reported improvement.33 . -r- OPERATING ROOMS Jg The widest application of air conditioning in hospitals is in operating^ rooms. Complete air conditioning of operating wards is important be-;.;^ cause winter humidification helps reduce the danger incident to the. use of T; anesthetic gases; summer cooling with some dehumidification tends tojj/,; eliminate excessive fatigue and to protect the patient and operating per-gy sonnel; and finally, filtering aids the removal of allergens from the operating^ room air. Reducing Explosion Hazard iff Explosion hazards in operating rooms increased with the introduction of anesthetic gases and apparatus. Ether administered by the old droj)|;| method gives rise to an explosive mixture, but in practice this method isfe still regarded as comparatively safe. When ether is mixed with pure oxy-Jy gen, or nitrous oxide in certain concentrations, the explosion hazard mayy^ be as great as with ethylene-oxygen, or cyclopropane-oxygen mixtures.^ Of the anesthetic gases nitrous oxide alone does not explode.but supports|| combustion. Ether, vinyl ether, ethylene, and cyclopropane are as poten-Ju tially dangerous as gasoline or illuminating gas in the home.34 Chloroform; does not explode violently in contact with flame, but decomposes to liberated phosgene. All of the anesthetic gases and vapors, except ethylene, are heavier than air. Although the incidence of injury or death from explosion^ is negligible compared with other hazards in the operating room, the dra-f^ matic features surrounding an explosion justify continued investigation^* to eliminate the hazard. j During the course of ethylene anesthesia, the mixture, usually 80 per-.gi cent ethylene and 20 percent oxygen, is so rich that the danger of explosion^ is slight in the immediate vicinity of the face mask, but leakage of ethylenefc into the air may accumulate to any lower concentration, and thus introduce# a serious hazard. The most dangerous period is at the end of the operation, when the patient's lungs and the anesthesia apparatus are customarily: washed out with oxygen with or without the addition of carbon dioxide.; Even when this procedure is omitted, it is difficult in practice to avoid dilution of the anesthetic gas with air during the normal course of breathing; following the administration. In either case the mixture would pass, through the explosion range and extraordinary precaution is necessary for. the safety of the patient and operating personnel. Air Conditioning in Prevention and Treatment of Disease 139 In a study35 of 230 anesthetic explosions and fires, 70 percent of the ex plosions and 60 percent of the deaths were'caused by igniting agents other than-static sparks. The National Fire Protection Association36 made certain recommendations for safe practice based on available informa tion in Pamphlet No. 56, Recommended. Safe Practice- for HospitalOperating Rooms (July 1952). These recommendations outline in some detail ways and means for eliminating or correcting hazardous conditions which experience and investigation have shown to contribute to the hazards in question. They are divided into three parts: Part I, General, deals with the nature of the hazards, Part II, Construction and Equipment, deals with physical standards for features incorporated into the construction :and equipment of the surgical suite, and Part III, Administration, contains precautions to be observed by hospital personnel. The requirements and recommendations are interdependent and each will be ineffective unless coordinated with the other. To approach complete success in the preven tion of anesthetic explosions, all persons--the surgical staff, the nursing staff, the maintenance staff and administrative personnel--must be edu cated and periodically reminded of the explosive nature of combustible anesthetic agents. Experience has shown that neither high humidity nor intercoupling devices have eliminated the danger from static electric discharge. The removal of gas concentrations from the operating table area, by means of specially devised exhaust ventilation, should be thoroughly tested. Port able duct systems as installed aboard ship should be acceptable. Serious, explosions can occur in a closed system, but proper precautions will reduce this hazard to a minimum A comprehensive study of the explosion problem and of the general causes and prevention of operating room hazards, by the University of Pittsburgh, AoHAE Research Laboratory, and the U. S.` Bureau of Mines has led to a fruitful attempt to eliminate the explosive range of cyclopropane, one of the best but most difficult gases to handle. The use of helium as a diluent in the total gaseous mixture controls the oxygen concentration by displacement and, because of its flame quenching properties, it is the ideal gas tor this purpose. In addition, a gaseous mixture containing helium is more difficult to ignite by electric discharges, and this quality also in creases the safety factor of anesthetic administration. 'jperatmg Room Conditions ^ ^nown about optimum air conditions for maintaining normal nprinH mPeratures during anesthesia and the immediate post-operative thp qH An anesthetized patient displays dilation of blood vessels in to rpini? "S ln Profdse sweating and (it has been believed) inability thptiS^ate , temperature. From this it was concluded that all anes- littlp H?ered considerable heat loss, although there may be of the p 6 i-n ^ var`at*on in the rectal temperature during the course sweatm^1011:, seycro physiological effects, such as excessive ants nnt raPld, Pulse, of high operating room temperatures on attend ing. St nip len^s during the hot months signify the need for proper cool- non-air cnnrrt- j surgeons who operate in both air conditioned and the Datient ;ltlone(f rooms strongly indicate that the recuperative power of Alth h Sreater when operated upon in air conditioned rooms.37 cal with thn> f6 cP1^ortable air conditions for the operators are not identi- a range of ss (rife Parient, it is usually not difficult to compromise within o 60 percent relative humidity and 72 to 80 F temperature.