Document 0dbzYyn0wjpd8YB6D113YwZb

HEATINC VENTILATING AIR CONDITIONING GUIDE 1942 100 F) according to the constitutional state of the infants and body- weights. The optimum relative humidity was about 65 per cent, and the air -movement less than 20 fpm. A single nursery conditioned to 77 F and 65 per cent relative humidity was found to fulfill satisfactorily the requirements of the majority of premature infants. Additional heat for weak (or debilitated) infants may be furnished in the cribs or by means of electric incubators placed inside the conditioned nursery, and the temperature adjusted according to individual requirements. In this way multiplicity of chambers and of air conditioning apparatus is obviated; the infants in the heated beds derive the benefit of breathing cool humid air, and the nurses and doctors need not expose themselves to extreme conditions. Importance of Humidity: Although external heat is an important factor in the maintenance of normal body temperature, humidity appears to be of equal or greater importance. .. When the premature nurseries at: the Infants Hospital were kept at relative humidity between 25 and 50 per cent for two weeks or longer, the body temperature became unstable, gain in weight diminished, the incidence of gastro-intestinal disturbances increased, and the mortality rose. On the other hand, continuous exposure to air conditions with 55 to 65 per cent relative humidity gave satisfactory results over a period of years. The effect of humidity on mortality is shown in Table 3. The initial physiologic loss of body weight (loss occurring within first four days of life) was found to vary inversely with the humidity. In the old nurseries with natural humidity it aver* aged 12.4 per cent of the birth weight; in the conditioned nurseries it was 8.9 per cent with 25 to 49 per cent relative humidity, and 6.0 per cent with 50 to 75 per cent relative humidity. The number of days required to regain the birth weight was correspondingly maximum in the old nursery and minimum in the conditioned nurseries under high humidity. Maximum gains in body weight occurred in the conditioned nurseries under high humidity (55 to 65 per cent) in infants weighing less than 5 lb. The gains were less under low humidity (25 to 50 per cent) in the same nurseries, and in the old nurseries prior to the installation of air conditioning apparatus. The incidence and severity of digestive syndromes, with diarrhea, persistent vomiting, diminishing gain or. loss of body weight, and other symptoms, were generally from two to three times as high under low than under high humidity. . Summarizing, the best chances for life in premature infants are created by maintaining a relative humidity of 65 per cent in the nursery and by providing a uniform environmental temperature just sufficiently high to keep the body temperature within normal limits. Medical and nursing care are, of course, factors of equal and sometimes of greater importance. , Air Conditioning Equipment Most of the installations now in use are of the central system type providing for filtration, for humidification and heating in cold weather, and for cooling and dehumidification in hot weather. A high ventilation rate, between 15 and 25 air changes, is desirable to remove odors and, 702 CHAPTER 37. AIR CONDITIONING IN THE TREATMENT OF DISEASE maintain uniformity of temperatures in extremes of weather. Recircu lation is not used extensively in these wards owing to odors and the possibility of infection. FEVER THERAPY Artificial production of fever in man is an imitation of nature's way of overcoming invading pathogenic organisms. The action may be direct and specific by destruction of the invading organism within the safe limit of human temperatures, or indirect in the.case of heat resistant organisms, by general mobilization of the defensive mechanisms of the body, which retard or neutralize the activity of pathogenic bacteria and their toxins. The limits of induced systemic fever are usually between 104 and 107 F (rectal), and the duration from 3 to 8 hours at a time. The total period of fever treatment varies with the type of the organism involved from a few hours to 50 or more. The diseases which respond favorably to artificial fever therapy are gonorrhea and its complications, (which include arthritis, pelvic in fections in women, and involvement of the eye), syphilis, chorea, infec tious arthritis (non-gonorrheal), encephalitis, and some forms of asthma. There are other conditions which show.promise; under this treatment, but the most striking results are seen in gonorrhea and syphilis, since the causative organisms can be destroyed at temperatures compatible with human life9. Equipment for Production of Fever Various means have been tried for producing artificial fever, including injections of various crystalloid or colloid substances, bacterial products of typhoid and malarial organisms; a number of physical methods, such as hot baths, radiant heat, diathermy, radiothermy, and in the last few. years, air conditioned chambers., The relative advantages and dis-; advantages of various methods have been discussed in a paper10. The. results by the use of air conditioned cabinets have not been fully explored, and it is therefore difficult to determine, alf the advantages and disadvantages of the value of air conditioning at this ;time. In the earlier studies of the Society11, temperatures were elevated more easily using saturated atmospheres. A fever therapy apparatus11^ using these same principles has proved efficient as'a means of inducing' and maintaining fever in a body with small likelihood of burns because^ of the comparatively low dry-bulb temperatures. This saturation factor is in great use today where fever is created by induction currents by Report of the First Year of Fever Therapy Research by the Department of Industrial Hygiene. School of Medicine. University of Pittsburgh. 1938. "Fever Therapy by Physical Means, by Frank H. Krusen and E. C. Elkins (Journal American Medical Association, 112: 1689-1696, April 29. 1939). "A S H V E Research Report No. 654--Some Physiological Reactions-of High Temperatures and Humidities, by W. J. McConnell and F. C. Houghten (A.S.H.V.E. Transactions. Vol. 29, 1923. p. 129). "A.S.H.V.E Research Report No. 1054--Fever Therapy Induced by Conditioned Air. by F. C. Houghten. M. B. Ferderber and Carl Gutberlet (A.S.H.V.E. Transactions. Vol.' 43, 1937, p: 131). A S H V E. Research Report No. 1162--Fever Therapy Locally Induced.by Conditioned Air, by M. B. Ferderber. F. C. Houghten and Carl Gutberlet (A.S.H.V.E. Transactions. Vol. 46, 1940). 703