Newborn infants, especially those of low birth weight, face a variety of environmental hazards in the new air-filled world into which they have emerged (Table 1). The very temperature and constituents of air are immediate threats, as are the loving but often unclean hands of well-intentioned human contacts.
In the past, swaddling clothes, a diet limited to breast milk, and the constant attention of the mother were major safeguards against the hostile environment. As attempts were made to salvage premature infants, attention focused on the need to control the thermal environment and to isolate infants from contaminants and infectious agents. This reflected a recognition of the major developmental inadequacies of the premature infant, who was best suited for the warm, watery environment of the uterus.
More recently, with the evolution of efforts to salvage even more compromised neonates, newer environments have been created in special-care units. In addition to the hazards of the natural environment that these infants face are those associated with the very devices and treatment regimens that have been developed to sustain, monitor, and protect them. Drugs and cleaning agents as well as such devices as monitors, incubators, radiant heaters, and ventilators, designed to protect the patient, have inherent hazards of their own. Noise produced by the various devices and background noise produced in the unit may affect the development of hearing.
This article focuses on some of the hazards present in the "protected" environment of the newborn nursery and is designed to stimulate awareness of some of the undesirable side effects associated with modern neonatal care.
TOXICITY AND DEVELOPMENT
Illustrative of the tight balance between risk and benefit associated with introduction of anything into the environment of the newborn infant is the long-recognized risk of high oxygen concentration. The discovery that the development of retrolental fibroplasia occurred as a complication of this therapy took many years but eventually brought into focus the problem of the unpredictability as well as the very special nature of specific hazards to the newborn or unborn. The uniqueness of the host, related to his stage of development, makes prediction of effect impossible from trials in other animal species or even from experience gained in adults of the human species.
This lesson has had steady but remarkably slow influence on the introduction of new drugs, devices, and procedures. There is need for broader input from developmental and basic scientists into the anticipation of possible deleterious effects of newer treatment modalities.
From the lessons of special threats to the fetus and neonate produced by thalidomide, chloramphenicol, and sulfonamides, more attention is being paid to the special metabolic features of the developing newborn infant and to the need for understanding his modes of detoxifying these agents. It is unfortunate, however, that an easy "out" for pharmaceutical companies has been to warn against use of drugs in infants without specifically examining the influence of the agent because of the complexity of such testing.
ENVIRONMENTAL HAZARDS IN THE NEWBORN NURSERY
There is rapidly growing awareness that alcohol and other toxic agents from the environment, such as PBBs entering the mother, may not only reach the fetus prenatally, but also during labor and, postnatally, in breast milk (Table 2). It has also become clear that clinical manifestations in the mother and infant may be different not only in degree but also in their very nature (for example, fetal alcohol syndrome).
Low-birth-weight and other jeopardized infants are constantly facing hazards of adverse thermal conditions. Although much has been learned about the optimal thermal environment for these infants over the past 15 years, both hypothermia and, to a lesser extent, hyperthermia continue to pose problems and are associated with increased morbidity and mortality.
The initial thermal threat to the neonate is the environment of the delivery room, where air temperature may be as low as 20-220C. Emerging wet from an intrauterine environment at 38°C, the neonate rapidly loses heat, mostly from evaporation. While healthy full-term infants can tolerate this initial cold stress, significant hypoxemia and acidosis may occur in compromised infants who are hypothermic. Resuscitation is made more difficult under these conditions. It is extremely important to place the latter group of patients under open radiant heaters immediately after delivery to minimize heat loss.1
Once they are transported to the nursery, maintenance of a thermoneutral environment for these infants through the use of standard incubators or open radiant heaters is vital.2 Thermoneutrality (the narrow range of environmental temperatures associated with minimal rates of oxygen consumption) is best maintained by using the servocontrol mechanism present on both of these devices. For low-birth-weight infants, abdominal skin temperatures should be maintained between 36.4° and 36.80C, and for full-term infants between 36.0° and 36.3°C. This is usually associated with axillary and colonic temperatures of 36.8° to 37.0°C.
Inadvertent exposure to subthermoneutral temperatures and the resulting hypothermia can lead to increased oxygen consumption, decreased pulmonary blood flow, hypoxemia, acidosis, and decreased growth.3 Some of the factors that lead to hypothermia are faulty equipment (especially broken thermistor skin probes), failure to calibrate the incubator servo control mechanism, and faulty placement of skin probes. Removing infants from incubators to do procedures and leaving incubator portholes open for prolonged periods of time leads to increased heat loss and hypothermia. Excessive radiant-heat loss may occur when an incubator is placed near a cold window or air conditioner. Radiant-heat loss may be decreased by the use of double-wall incubators, which are now commercially available.
The convective heat source of standard incubators may be inadequate for providing a thermoneutral environment for very low-birth-weight infants, especially those weighing less than 1 kg. These infants should be cared for under open radiant heaters. When these devices are used, care should be taken to avoid convective-heat losses secondary to drafts. A very high insensible water loss (not associated with an increase in oxygen consumption) occurs in infants cared for under radiant heaters.4-6 Adequate fluids must be provided for these infants.
LIKELIHOOD OF VARIOUS DRUGS PRODUCING ADVERSE EFFECTS IN NURSLINGS
Hyperthermia is far more often of iatrogenic than infectious origin in newborn infants. (Hypothermia rather than fever usually accompanies neonatal infection). As in the case of inadvertent hypothermia, environmental temperatures above the thermoneutral zone are usually due to improper use of incubators and radiant heaters. Since preterm infants have an impaired ability to sweat in the presence of an excessively warm environment, care must be taken to avoid overheating. Hyperthermia can also occur in otherwise normal full-term infants on very hot summer days in non- air-conditioned nurseries. Removal of shirts, diapers, and blankets will allow heat to be dissipated, and the infant's temperature then returns to normal.
Potential and actual adverse side effects. That the approach to the introduction of new devices and treatments for the neonate is stili "uncontrolled" is illustrated by the long gap between the introduction of phototherapy for neonatal hyperbilirubinemia, in 1958, and the development of studies of its long-term implications for development (1974). At this writing, although much has been learned about the effect of light, its actual impact on bilirubin in vivo and its potential for both risk and benefit are under investigation, though it is used worldwide in almost every hospital that treats infants.
Acute effects. Although there have been no reports of serious long-term side effects of phototherapy, several clinical observations have been made of acute clinical problems during its administration. These include the occurrence of frequent greenish loose stools,7 transient skin rashes,8 and transient bronze discoloration of the skin in infants with direct bilirubinemia.9 Increased insensible water loss as well as increased peripheral skin blood flow have also been reported and have led to recommendations of compensatory adjustment in fluid intake during therapy.4,10,11 One of the problems associated with light therapy is that jaundice may disappear despite a lack of definition of the underlying cause, and it is always important to stress that phototherapy should not be utilized without investigation of the cause of jaundice.
It should also be appreciated that if phototherapy is used to control jaundice associated with ABO or Rh-hemolytic disease, sensitized red blood cells will continue to be destroyed by the underlying process and, though jaundice may be controlled, anemia secondary to the hemolytic process should be anticipated. Frequent hemoglobin determinations must be made even after discharge of the infant from the hospital, and simple transfusion may become necessary.
The question of the direct effect of phototherapy on survival of red blood cells has not been answered. While in vitro studies using doses of light in excess of those employed in clinical situations have indicated that damage to red cell membranes can occur, in vivo studies as well as clinical observations have not confirmed this finding.9,11
Long-term implications of phototherapy. A delay in weight gain occurs in infants receiving phototherapy when there is not supplemental fluid and calorie intake. Catch-up weight gain occurs subsequently.12
Although phototherapy has been reported to affect the growth of infants, particularly head growth,13 follow-up studies by the original author as well as others have failed to confirm these findings.14-20 Further, studies by Ballowitz,21 which suggested growth retardation in Gunn rats treated with phototherapy, have also been retracted.22
Effect on vision. When phototherapy is applied clinically, the infant's eyes are shielded in some manner because it has been assumed that visual damage may occur during exposure. The actual effect of such exposure on the development of vision is not known, nor is there a study of the amount of light that actually penetrates each of the various types of eye shields. Further, the possible detrimental effects of the shielding itself (with concomitant visual sensory deprivation) has not been assessed.
While little is known of the possible toxic effects of light on human beings, particularly infants, there is a great deal of information available from animal experiments. It is dangerous to assume that generalizations can be made across species, but these experiments do suggest a potential hazard to retinal structures. Studies to date suggest damage not only from the light itself but from lack of change in illumination for several days as well as from inadequate protection by eye occluders. Various studies have shown that retinas of rats, monkeys, piglets, and birds can be severely damaged by exposure to moderate light levels within the range obtained in phototherapy units as applied clinically. Damage to retinas of macaques has been shown to be quite specific, even though it is difficult to detect.23,24 Repeated short doses of blue irradiance over several days produces irreversible loss of blue -cone response.25 This psychobehavioral finding corresponds to the histologic demonstration that the distribution of damage is in the area of the blue cones.26 These studies suggest that cones containing the photopigment that maximally absorbs the short wave lengths have a comparatively low damage threshold.
Potential effects on DNA. Recent reports of in vitro studies suggest that phototherapy has the potential of altering the genetic material of prokaryotic as well as eukaryotic cells at wavelengths, as well as dosage, similar to those used in clinical practice.27,28 Since modifications of cellular DNA can have genetic as well as carcinogenic consequences, it is important that if light is to be used to treat jaundice, it should be used only when needed and in the most efficient, least noxious manner. It is also important to note that, in general, deleterious in vitro effects have not been observed to occur in vivo.
It should be stated that while many potential hazards of phototherapy have been investigated, to date no serious long-term deleterious effects have been observed during the 20 years in which phototherapy has been applied. The National Institute of Child Health and Human Development is currendy sponsoring a controlled long-term follow-up study to assess these potential dangers.
Newborn infants, especially those who are born prematurely, have limited host defense mechanisms, and are therefore particularly susceptible to infection. A number of environmental factors in the newborn nursery (and in particular the neonatal intensive-care unit) may increase this risk. These include carriage of potentially pathogenic microorganisms on the hands of physicians and nurses, overcrowding, inadequate cleaning of such equipment as incubators, nebulizers, and ventilator tubing, umbilical catheters, parenteral alimentation, and exposure of infants to staff members, visitors, and other infants with communicable diseases.
Hand washing. Of ail the hazards to which the newborn infant is subjected, the most significant is contamination from unwashed hands. Before entering the nursery, personnel should remove all jewelry and roll sleeves up to the elbows. After a preliminary wash and cleansing of nails, hands and arms should be scrubbed for about two minutes, preferably with a disposable soft pad or brush. The type of soap used is probably not critical, although iodophor preparations, which are active against both gram-negative and grampositive bacteria, have gained a wide degree of popularity. Before examination of each infant or after touching a potentially contaminated article, hands should be rewashed for about 15 seconds.29
Although proper hand-washing technique is effective in removing transiently acquired bacteria,30 there is evidence that the hands of some personnel may be colonized by drug-resistant-gram negative bacilli, which cannot be easily eradicated by hand washing. It has been suggested that promiscuous use of aminoglycoside antibiotics in neonatal units may be the reason for the emergence of these drug-resistant organisms, which may then serve as a reservoir for nosocomial infections.31
It should be noted that hexachlorophene, an antistaphylococcal cleansing agent used widely in the 1960s and early 1970s,32 is readily absorbed through the skin of neonates (especially those of low gestational age) and may cause histologic changes in the brain.33 Its use has been greatly limited over the past few years.
Overcrowding. Since overcrowding in a nursery may lead to increased rate of infection, it is manadatory that adequate space be provided for each infant. In the normal full-term nursery, at least 20 square feet should be provided for each infant, with at least 3 feet between bassinets. The intermediate-care area should provide 40 to 60 square feet per infant and in the intensive-care area 80 to 100 square feet per infant should be allocated.29
Cross infection. Both personnel and visitors with evidence of infection must be excluded from the newborn nursery. However, the problem of preventing infant-to-infant cross-infection is more difficult. While the use of isolation rooms may be advantageous in the presence of such highly communicable diseases as congenital rubella and infection secondary to multi-drug- resistant Klebsiella and other enteric pathogens, they may be unnecessary in most other instances, as long as there is no overcrowding and there are separate nursing staff for infected and non-infected infants and adherence to proper hand-washing techniques.29
Cleaning and disinfection. The physical environment of the nursery may serve as a source of pathogenic bacteria. Floors, windows, and walls should be washed at frequent intervals with a detergent-disinfectant and dust levels kept to a minimum. Bassinets, incubators, and radiant heaters should be thoroughly cleaned after use for an infant. Equipment used in respiratory therapy, such as ventilators, tubing, nebulizers, laryngoscopes, and face masks, are particularly prone to contamination and must be meticulously cleaned and disinfected. Strict adherence to maintaining a clean physical environment will decrease the possibility of nursery infection.29 Recent experience indicates that attention must be paid not only to the adequacy of a cleaning agent but also to its potential side effects.
Electrical hazards. In any intensive-care unit, electrical monitoring equipment which is attached to the patient has the potential for causing fatal electrical shock.34,35 Death from ventricular fibrillation secondary to leakage of alternating current may occur with either external application (such as ECG skin electrodes) or through a low-resistance pathway to the heart via an internal conduit, such as a blood- or saline-filled umbilical arterial or venous catheter. In adults, a current of 100 microamperes applied to the skin or 20 microamperes applied directly to the heart may cause ventricular fibrillation. In neonates, this may be as low as 10 microamperes.
Although all electrical instruments are insulated in order to prevent (or greatly minimize) leakage of current to the instrument casing, some leakage invariably occurs (and may worsen as the instrument has been in protracted use). In some situations, this leakage may be unacceptably high. As a safety feature, all metal parts of a device not meant to carry current must be grounded, in order to minimize the potential difference (and likelihood of electric shock) between the patient and piece of equipment. This is accomplished by the use of a three-prong plug and a three-wire power cord, with the third wire diverting leakage current from the apparatus to the ground. Manifestations of improper grounding include interference on ECG or oscilloscopic displays and erratic function of the device. Electric shock received by nursery personnel when they touch a device is an ominous sign of faulty equipment that may threaten the life of the infant.
In order to minimize the hazard of inadvertent electric shock to the sick neonate, constant vigilance is required.36 A program of preventive maintenance is mandatory. The hospital's bioengineering department must carry out regular and frequent inspections of all electrical instruments, wiring, and power outlets and institute corrective measures when indicated.
Exposure to high levels of noise can lead to permanent hearing loss. The incidence of hearing loss is many times greater among low-birth-weight infants than those born at term, and it has been speculated that this may be at least in part due to excessive noise exposure in the newborn nursery, especially in the neonatal intensive-care unit.37"39 This loss may be greatly potentiated by such ototoxic antibiotics as gentamicin and kanamycin, which are commonly used in this group of infants. A significant number of low-birth-weight infants (3 per cent or more) are asymptomatic carriers of cytomegalovirus. This organism has a predilection for the cochlea and is frequently a cause of hearing loss. The additional long-term effects of nursery noise in these compromised infants is not known.
Excessive noise, especially if continuous, leads to damage of the hair cells of the organ of Corti. High frequency noise appears to be more harmful than low frequency noise, and in adults, a high frequency hearing loss occurs before a low frequency loss. There is experimental evidence that newborn animals are more susceptible than adult animals to the same magnitude of noise.
In a neonatal intensive-care unit, infants continuously cared for in the confined environment of incubators are subjected to a variety of continuous noises. The most important of these is the noise caused by the motors of incubators, which range from 50 to 86 decibels. (A daily exposure of 80 db over an eight-hour period is considered a safe level for a human adult. At 58 db, neonatal guinea pigs who received kanamycin for five weeks developed cochlear damage.)40 In addition, there is the additive effect of monitor alarms, opening and closing of incubator doors, radios, telephone ringing, the conversation of visitors and staff members, and the noise produced by the infant himself when he cries.
Not only is the magnitude of this problem unknown, but it may extend beyond the obvious effect on the development of hearing. For example, increased noise may contribute to the frequency of apneic-episodes and hypoxemia. Several steps can be taken to minimize the deleterious effects of this environmental hazard. These include judicious use of aminoglycoside antibiotics (and perhaps caring for infants receiving these drugs under open radiant heaters rather than in incubators) and in minimizing unnecessary background noise, such as playing of radios and loud conversations. Manufacturers should strive to reduce noise levels produced by incubator motors and monitoring devices. Finally, all infants, especially those at highest risk, should be carefully tested for evidence of hearing loss.
NURSERY ENVIRONMENTAL LOG
In recognition of the effect of the environment on the health of the newborn infant, the American Academy of Pediatrics Committee on the Fetus and Newborn has for many years recommended that a log be kept by nursing staff to summarize any significant events occurring within a 24-hour period in the nursery. It is suggested that in addition to indicating the condition of new admissions and changes in the health status of the other infants, notation be made of introduction of new procedures, techniques, or supplies; changes in drug preparations (including changes in concentration); changes in patient census; and illness or absence of personnel.
The committee's handbook concerning hospital care of newborn infants29 emphasizes what is too frequently overlooked - that is, special attention should be given to chemical substances in the nursery, not only drugs but also insecticides or compounds used in the sterilization and marking of linens, nursery bottles, and equipment.
Since "toxic" substances may lead to increased incidence of neonatal hyperbilirubinemia, the staff should be encouraged to monitor its incidence and usual causes. If a change in incidence occurs, the environmental log may hold the clue. Recently, hyperbilirubinemia was traced to the use of phenolic detergent used as a nursery-cleaning agent.41 An "outbreak" of bleeding in another nursery was traced to a change in the concentration of heparin (1:1,000 to 1:100) that was not noticed by the staff. An environmental log should make the staff aware that changes in any aspect of the infant's environment may effect him.
Space does not permit the cataloging of all the hazards in the present-day nursery. What is more important is to raise our level of awareness concerning the actual and potential hazards in the environment of the neonate - that we recognize the unique effects of these challenges upon the neonate because of his stage of development and because his metabolism is different from that of the adult.
The long-term implications for the quality of life of all that we do and fail to do to for the neonate are greater at this time than what they would be at any other time of life.
1. Dahm, L. S-, and James L. S. Newborn temperature and calculated heat loss in the delivery room. Pediatrics 49 (1972), 504.
2. Hey, E., and Katz, G. Optimal thermal environment for naked babies. Arch. Dis. Child 45 (1970), 328.
3. Evans, H. E., and Glass, L. Perinatal Mediane. Hagerstown, Md.: Harper and Row, 1976, pp. 277-287.
4. Wu, P. Y. K., and Hodgman, J. E. Insensible water loss in preterm infants: changes with postnatal development and non-ionizing radiant energy. Pediatrics 54 (1974), 704.
5. Bell, E. R, Neidich, S. A., Cashore, W. j., and Oh, W. Combined effect of radiant warmer and phototherapy on insensible water loss in low-birth-weight infants. J. Pediatr. 94 (1979), 816.
6. Darnali, R. A., and Ariagno, R. L. Minimal oxygen consumption in infants cared for under overhead radiant warmers compared with conventional incubators. J. Pediatr. 93 (1978), 283.
7. Washington, J. L., Brown, A. W., and Starrere, A. L. The question of diarrhea and phototherapy. Pediatrics 49 (1972), 279.
8. Lucey, J. F. Neonatal jaundice and phototherapy. Pediatr. Clin. North Am. 19 (1972), 827.
9. Kopelman, AE., Brown, R. S., and Odeil, G. B. The "bronze baby," a complication of phototherapy. J. Pediatr. 81 (1972), 466.
10. Wu, P. Y., Wong, W., Hodgman, J-, Levau, N. Changes in blood flow in the skin and muscle with phototherapy. Pediatr. Res. 8 (1974), 257.
11. Blackburn, M. G., Orzatesi, M. M., and Pigram, P. Effect of light on fetal red blood cells in vivo. J. Pediatr. 80 (1972), 460.
12. Hodgman, J. E., Wu, P. Y. K., and Teberg, A. ). Clinical use of phototherapy with emphasis on acute and long term effects on growth. In Brown, A. K., and Showacre, J. (eds.). Phototherapy for Neonatal Hyperbilirubinemia. DHEW Pub. No. (NTH) 76-1075.
13. Hodgman, J., and Teberg, A. Effect of phototherapy in low birth weight infants on growth and development at 2 years. (Abstract) Clin. Res. 24 (1971), 224.
14. Wu, P. Y. K., et al. Effect of phototherapy in preterm infants on growth in the neonatal period. J. Pediatr. 85 (1974), 563.
15. Jurado-Garda, E., et al. Phototherapy in the management of neonatal hyperbilirubinemia. Bol. Med. Hasp. Infant. Mex. 27 (1970), 141.
16. Lucey, J. F. Phototherapy of jaundice. 1969 Bilirubin Metabolism in Birth Defects, Original Article Series 6 (1970), 63.
17. Obes-Polleri, J. Phototherapy in neonatal hyperbilirubinemia. Arch. Pediatr. (Uraguay) 38 (1969), 77.
18. Onishi, S., Yamakawa, T., and Ogawa, J. Photochemical and photobiological studies on the light-treated newborn infant. Perinatology 1 (1971), 373.
19. Peterman, H. D. Follow-up examination of children who as newborn infants had been treated with blue light. Kinderaerztl. Prax. 39 (1971), 271.
20. Seitz, B., and Friederiszick, M. Zur Behandlung der Neugeborenengel besucht mit tageslich tahnlichen Lichtquellen. Physikalische Medina 5 (1971), 399.
21. Ballowitz, L. Growth retardation in gunn rats. Neonatal bilirubin metabolism. In Hsia, D. Y., (ed.). Birth Defects Original Artide Series 6 (1971), 106.
22. Ballowitz, L. Review of recent data on phototherapy in gunn rats. Proc. XUI International Congress of Pediatrics, Vienna, Austria. Perinatology 1 (1971), 265.
23. Messner, K. H., Maiseis, M. J., and Leure-du Pree, A. E. Phototoxidty in the newborn primate retina. Invest. Ophthalmol. Vis. Sci. 17 (1978), 178.
24. Messner, K. H., Switaj, P., and Mariani, A. Light toxicity to the newborn nonhuman primate retina. Invest. Ophthalmol. Vis. Sci. Supplement (1978), 266.
25. Sperling, H. G. Effects of light on the retina. In Haggard, D. G., (ed.). Symposium on Biological Effects and Measurement of Light Sources. Rockvflle, Md.: Bureau of Radiological Health, DHEW pub. No- FDA 77-8002, 1976, pp. 47-63.
26. Sperling, H. G. Functional changes and cellular damage associated with two regimes of moderately intense blue light exposure in rhesus monkey retina. Invest. Ophthalmol. Vis. Sci. Supplement (1978), 267.
27. Speck. W. T., and Rosenkranz, H. S. Intracellular deoxyribonudeic add-modifying activity of phototherapy lights. Pediatr. Res. 10 (1976), 553.
28. SanteUa, R. M., Rosenkranz, H. S., and Speck, W. T. Intracellular deoxyribonudeic add-modifying activity of intermittent phototherapy. J. Perfiafr. 93 (1978), 106.
29. Standards and Recommendations for Hospital Care of Newborn Infants. Evanston, Ill.; American Academy of Pediatrics, 1977.
30. Sprunt, K., Redman, W., and Leidy, G. Antibarterial effectiveness of routine hand washing. Pediatrics 52 (1973), 264.
31. Knittie, M. A., Eitzman, D. V., and Baer, H. Role of hand contamination of personnel in the epidemiology of gram negative nosocomial infection. J. Pediatr. 86 (1975), 433.
32. Gluck, L., and Wood, H. F. Staphylococcal colonization in newborn infants with and without antiseptic skin care. N. Engl. J. Med. 268 (1963), 1265.
33. Shuman, R. M., Leech, R. W., and Alvord, E. K. Neurotoxidty of hexachlorophene in the human. I. A. dinicopathologic study of 248 children. Pediatrics 54 (1974), 689.
34. Chemick, V., and Raber, M. B. Electrical hazards in the newbom nursery. J. Pediatr. 77 (1970), 143.
35. Segal, S-, and Pirie, G. E. Equipment and personnel for neonatal spedai care. Pediatr. Clin. North Am. 17 (1970), 763.
36. Edwards, M. K. Specialized grounding needs. Clin. Perinatal. 3 (1976), 367.
37. American Academy of Pediatrics, Committee on Environmental Hazards. Noise pollution: neonatal aspects. Pediatrics 54 (1974), 475.
38. Blennow, G., Svenningsen, M. W., and Almquist, B. Noise levels in infant incubators (adverse effects?). Pediatrics 53 (1974), 29.
39. Bess, F. H., Peek, B. F., and Chapman, J. J. Further observations on noise levels in infant incubators. Pediatrics. 63 (1979), 100.
40. Douek, E., et al. Effects of incubator noise on the cochlea of the newborn. Lancet 2 (1976), 1110.
41. Daum, F., Cohen, M. L, and Mac Namarra, H. Experimental toxicologic studies on a phenol detergent associated with neonatal hyperbliirubinernia. J. Pediatr. 89 (1976), 853.
ENVIRONMENTAL HAZARDS IN THE NEWBORN NURSERY
LIKELIHOOD OF VARIOUS DRUGS PRODUCING ADVERSE EFFECTS IN NURSLINGS