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CHAPTER 6 Heat Balance
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Pulmonary vasoconstriction, accentuated by metabolic acidosis, is associated with hypoxia, decreased surfac­tant production, and further acidosis (see Chapter 23). Blood flow to vital organs is diminished, and pulmo­nary hemorrhage and death may occur if hypothermia continues.
Hyperbilirubinemia and kernicterus may occur as nonesterified free fatty acids from brown fat metabo­lism compete with bilirubin for albumin-binding sites. Acidosis not only decreases the affinity of albumin for bilirubin but also increases the permeability of the blood-brain barrier, allowing bilirubin to enter brain tissue. If hypothermia continues, carbohydrate, pro­tein, and fat supplies will be used for heat production instead of growth.
Close monitoring of the hypothermic infant is essential for early identification and prevention of complications. Evaluation of vital signs, arterial blood
gases, and oxygen saturation may give early indica­tion of hypoxia and metabolic acidosis. The infant’s skin may be dusky or bright red because failure of dissociation of oxyhemoglobin occurs at low body temperatures. Respirations may be rapid, shallow, and grunting and accompanied by bradycardia. Oxygen and ventilation should be initiated as needed to reduce hypoxia. Sodium bicarbonate may be needed to cor­rect documented metabolic acidosis. Seizures may occur as a result of hypoxia, requiring the administra­tion of anticonvulsants.
Intravenous glucose may be necessary to prevent or correct hypoglycemia. Blood glucose levels should
be monitored hourly until stable (see Chapter 15). Blood pressure and urine output should be mea­sured to evaluate hydration and kidney function. An
elevated BUN and hyperkalemia may be indicators of decreased renal perfusion and impaired renal function. As fluid is retained, edema of the extremities and face may occur.
Bilirubin should be monitored on a regular basis, and phototherapy may be initiated at a lower-than-usu­al level to prevent kernicterus. Adequate nutrition to promote growth should be given either intravenously or enterally. While the infant is hypothermic, nipple feedings should be avoided to conserve calories and energy for heat production and growth and to avoid aspiration. Hypothermic infants feed poorly and fail to gain weight because calories are used to generate heat for warmth instead of for growth.
During the rewarming process, the hypother­mic infant should be observed for hypotension as vasodilation occurs. Volume expanders may be
needed to maintain an adequate blood pressure. Apnea and seizures may occur as a result of hypoxia or decreased cerebral blood flow after vasodilation. Hypothermia as a strategy to minimize adverse out­comes from hypoxic-ischemic encephalopathy con­tinues to be the focus of considerable research to determine safety and efficacy (see Chapter 26).
HYPERTHERMIA
The hyperthermic infant may feel warm to touch, and skin color may be ruddy as the infant attempts to increase heat loss by vasodilation. Sweating may occur in a term infant but generally is not present in infants of less than 36 weeks gestation­al age. Sweating may first appear on the forehead,
followed by the chest, upper arms, and lower body. Hyperthermia is manifested by irritability, lethargy, hypotonia, apnea, a weak or absent cry, or poor feed­ing. Tachypnea or tachycardia may be seen as the infant attempts to increase heat loss.
Infants with thermal instability should be close­ly watched for changes in behavior, feeding pat­terns, and respiratory status. Temperatures should be monitored frequently in any infant exhibiting these symptoms or who feels cool or warm to touch. Early recognition of thermal instability may
prevent further consequences and possibly permanent injury or death (Box 6.10).
Treatment and Intervention
The usual approach to treating the hyperthermic infant is to cool by removing external heat sources
BOX
6.10
Critical assessment findings for hyperthermia are as follows:
• Reddened skin that is warm to touch
• Tachypnea
• Tachycardia
• Irritability, lethargy, hypotonia, weak cry
• Poor feeding
• Apnea
• Sweating in more mature babies
• Dehydration
CRITICAL FINDINGS HYPERTHERMIA
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and by removing anything that blocks heat loss. The most common causes of hyperthermia in intensive care nurseries are iatrogenic. Check the heating controls for proper function and therm­istors for proper position. Consider other sourc­es of heat (e.g., direct sunlight, heaters, lights) as possible causes of hyperthermia. Excessive bundling with blankets and a hat and elevated environmental temperature can cause a new­born’s body temperature to rise into the febrile range. When evaluating the treatment options in the hyperthermic infant, one should consider removing extra blankets or swaddling materials. Nonenvironmental causes of hyperthermia (e.g., infection, dehydration, CNS disorders) should be considered. During the cooling process, skin, axil­lary, and environmental temperatures should be monitored and recorded every 30 minutes.
Complications
Recognizing late preterm and term neonates who meet the criteria for neonatal cooling for HIE (see
Chapter 26, Box 26.7) and preventing hyperther-
mia is critical to decreasing morbidity and mortality. Outcomes of asphyxiated newborn infants who did not receive cooling in the NICHD Neonatal Research Network whole body cooling trial were studied at 18 to 22 months72 and at 6 to 7 years.70 Within the first 72 hours of life, asphyxiated newborns without cooling exhibited elevated temperatures that were associated with a four-fold increase in death or moderate disabil­ity.72 Follow-up of this cohort to ages 6.7 years found that the association between their elevated tempera­tures and death or IQ less than 70 persisted.
Vasodilation to increase heat loss may cause hypo-
tension and dehydration as a result of increased IWL.
Seizures and apnea may also occur as a result of high core temperature. Fluid status should be
monitored by assessing intake, output, electrolytes, serum and urine osmolality, skin turgor, and mucous membranes. Fluids should be adjusted to account for IWL. Blood pressure should be assessed to
detect hypotension, and volume expanders should be
administered as needed.
Cardiorespiratory monitoring to detect apnea
should be used. Ventilation may be needed if apnea
persists or is unresponsive to stimulation. Subtle signs of seizures may include facial grimacing, nystagmus, tremors, apnea, opisthotonos posturing, tongue thrust­ing, or staring (see Chapter 26).
70
PARENT/CAREGIVER TEACHING
While the neonate is in the NICU, parents should be
taught the importance of maintaining the newborn’s normal body temperature. Temperature should be taken before parents touch the infant through the portholes of the incubator or hold their infant. While
the infant is outside the incubator, monitor the skin temperature continuously with a telether­mometer. Unwrapping the infant to check the tem-
perature exposes him or her to cold stress. Additional heat sources (e.g., radiant warmer, hat, extra blankets) may be needed while parents hold the infant. Teach parents to monitor their infant’s temperature and to notify the nurse if it rises or falls (Box 6.11).
Before discharge, teach parents to take an accu­rate axillary temperature and to notify their physi­cian if it drops below 36°C (96.8°F) or rises above
37.8°C (100°F).4 A parent should not routinely take a rectal temperature. The temperature should
be taken whenever the infant feels cool or warm to the touch. The nurse should observe the parents taking the infant’s axillary temperature before discharge.
The home environment should be kept at a temperature that prevents heat and cold stress. A room temperature that is comfortable for the parent usually is suitable for the infant. The infant should be in clothing appropriate for the room tempera­ture. For example, if the parent requires a sweater to
BOX
6.11
• Teach parents how to take an axillary temperature on their newborn
• Teach parents how to dress their infant with clothes and blankets
• Teach parents appropriate safety precautions, which include verbal
• Teach parents to notify their infant’s primary health care provider im-
PARENT/CAREGIVER TEACHING TEMPERATURE REGULATION
and maintain the axillary temperature between 36.5°C and 37.4°C (97.7°F and 99.3°F).
and use an appropriate environmental temperature to maintain the baby’s temperature in the above range.
and written information about recognizing signs and symptoms of a sick/ill infant, as well as how the infant acts, including tempera­tures either higher than or, more commonly, lower than the range of
36.5°C to 37.4°C (97.7°F to 99.3°F).
mediately or to take the infant to the nearest emergency department for temperatures out of the above range, especially if the baby’s feeding pattern changes.
5
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be comfortable, the infant probably also requires a sweater. Parents often overdress the infant or over­heat the home, and this may cause hyperthermia. Parents should be given written instructions before discharge on how and when to take an axillary temperature, when to call the physician, and how to maintain a comfortable environment for their infant.
REFERENCES
1. Adamkin D, Carlo W, Dreyer G, et al. Thermoregulation. In. Neonatal Clinical Management Guidelines. 5th ed. Upper Saddle River, NJ: Paradigm Health; 2007.
2. Agren J, Sjors G, Sedin G. Ambient humidity influences the rate of skin barrier maturation in extremely preterm infants. J Pediatr. 2006;148(5):613–617.
3. Altimier L. Thermoregulation: what’s new? What’s not? New- born Infant Nurs Rev. 2012;12:51.
4. American Academy of Pediatrics; American College of Obste­tricians and Gynecologists. Guidelines for Perinatal Care. 8th ed. Elk Grove Village, IL: The Academy; 2017.
5. Anderson GC, Lane AE, Chang H. Axillary temperature in transitional infants before and after tub bath. Appl Nurs Res. 1995;8(3):123.
6. Andrews C, Whatley C, Smith M, et al. Quality-improvement effort to reduce hypothermia among high-risk infants on a mother-infant unit. Pediatrics. 2018;141(3):e20171214.
7. Backes CH, Huang H, Iams JD, et al. Timing of umbilical cord clamping among infants born at 22 through 27 weeks’ gesta­tion. J Perinatol. 2016;36(1):35.
8. Barone G, Corsella M, Papacci P, et al. Feasibility of transfer­ring intensive cared preterm infants from incubator to open crib at 1600 grams. Ital J Pediatr. 2014;40:41.
9. Berger I, Marom R, Mimouni F, et al. Weight at weaning of preterm infants from incubator to bassinet: a randomized con­trolled trial. Am J Perinatol. 2014;31(6):535.
10. Bergman N, Linley LL, Fawcus SR. Randomized controlled trial of skin-to-skin contact from birth versus conventional incubator for physiological stabilization in 1200–2199 gram newborns. Acta Paediatr. 2004;93(6):779.
11. Bergstrom A, Okong P, Ransjo-Arvidson AB. Immediate ma­ternal thermal response to skin-to-skin care of newborn. Acta Paediatr. 2007;96(5):655.
12. Billimoria Z, Chawla S, Bajaj M, et al. Improving admission temperature in extremely low birth weight infants: a hospi­tal-based multi-intervention quality improvement project. J Perinat Med. 2013;41(4):455.
13. Billner-Garcia R, Spilker A, Goyal D. Skin-to-skin contact: newborn temperature stability in the operating room. MCN Am J Matern Child Nurs. 43(3):158.
14. Blackburn S, DePaul D, Loan LA, et al. Neonatal thermal care, part III: the effect of infant position and temperature probe placement. Neonatal Netw. 2001;20(3):25.
15. Boyd H, Brand MC, Hagan J. Care of 500 to 1500 gram premature infants in hybrid incubator. Adv Neonatal Care. 2017;17(5):381.
16. Brogan J, Rapkin G. Implementing evidence-based neonatal skin care with parent-performed delayed immersion baths. Nursing Women’s Health. 2017;21(6):442.
17. Bryanton J, Walsh D, Barrett M, et al. Tub bathing versus tradi­tional sponge bathing for the newborn. J Obstet Gynecol Neonat Nurs. 2004;33(6):704–712.
18. Caka SY, Gosen D. Effects of swaddled and traditional tub bath­ing methods on crying and physiologic responses of newborns. J Spec Pediatr Nurs. 2018;23(1). https://doi:10.111/jspn.12202.
19. Caldas JPS, Millen FC, Camargo JF, et al. Effectiveness of a quali­ty measure program to prevent admission hypothermia in very low-birth weight preterm infants. J Pediatr. 2018;84(4):368.
20. Cardona-Torres LM, Amador-Licona N, Garcia-Campos ML, Guizar-Mendoza JM. Polyethylene wrap for thermoregula­tion in the preterm infant: a randomized trial. Indian Pediatr. 2012;49(2):129.
21. Carns J, Kawaza K, Quin MK, et al. Impact of hypothermia on implementation of CPCP for neonatal respiratory distress syn­drome in a low-resource setting. PLoS One. 2018;13(3):e0194144.
22. Castrodale V, Rinehart S. The golden hour: improving the stabilization of the very low birth-weight infant. Adv Neonatal Care. 2014;14(1):9.
23. Chang HY, Sung YH, Wang SM, et al. Short-and long-term outcomes in very low birth weight infants with admission hypothermia. PLoS One. 2015;10(7):e0131976.
24. Charpak N, Ruiz JG, Zupan J, et al. Kangaroo mother-care: 25 years after. Acta Paediatr. 2005;94(5):514.
25. Cole J, Brissette N, Lundari B. Tub baths or sponge baths for newborn infants? Mother Baby J. 1999;4:39.
26. Colwell A. To bathe or not to bathe: the neonatal question. Neonatal Netw. 2015;32(4):216.
27. Conde-Agudelo A, Diaz-Rossello JL. Kangaroo mother care to reduce morbidity and mortality in low birthweight infants. Cochrane Database Syst Rev. 2016;8:CD002771.
28. Cone Jr TE. History of the Care and Feeding of the Premature Infant. Boston, MA: Little. Brown; 1985.
29. Datta V, Saili A, Goel S, et al. Reducing hypothermia in new­borns admitted to a neonatal care unit in a large academic hospi­tal in New Delhi, India. BMJ Open Quality. 2017;6(2):e000183.
30. DeAlmeida MF, Guinsburg R, Sancho GA, et al. Hypother­mia and early neonatal mortality in preterm infants. J Pediatr. 2014;164(2):271.
31. DeGorre C, Decima P, Degrugilliers L, et al. A mean body temperature of 37 degrees C for incubated preterm infants is associated with lower energy costs in the first 11 days of life. Acta Paediatr. 2015;104(6):581.
32. DeGuines C, Degrugilliers L, Ghyselen L, et al. Impact of nurs­ing care on the temperature environment in preterm newborns in closed convective incubators. Acta Paediatr. 2013;102(3):e96.
33. Delanaud S, Decima P, Pelletier A, et al. Additional double-wall roof in single-wall, closed, convective incubators: impact on body heat loss from premature infants and optimal adjustment of the incubator air temperature. Med Eng Phys. 2016;38(9):922.
34. Doglioni N, Cavallin F, Mardegan V, et al. Total body polyeth­ylene wraps for preventing hypothermia in preterm infants: a randomized trial. J Pediatr. 2014;165(2):261.
35. Dollberg S, Rimon A, Atherton HD, Hoath SB. Continuous measurement of core body temperature in preterm infants. Am J Perinatol. 2000;17(5):257.
36. Dollberg S, Mimouni FB, Weintraub V. Energy expenditure in infants weaned from a convective incubator. Am J Perinatal. 2004;21(5):253–256.
37. Don Paul JM, Perkins EJ, Pereira-Fantini PM, et al. Surgery and magnetic resonance imaging increase the risk of hypothermia in infants. J Paediatr Child Health. 2018;54(4):426.
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38. Duran R, Vatansever U, Acunas B, Sut N. Comparison of temporal artery, mid-forehead skin and axillary temperature recordings in preterm infants <1500 g of birthweight. J Paediatr Child Health. 2009;45(7-8):444.
39. Duryea EL, Nelson DB, Wyckoff MH, et al. The impact of ambient operating room temperature on neonatal and maternal hypothermia and associated morbidities: a randomized con­trolled trial. Am J Obstet Gynecol. 2016;214(4):505.
40. Edraki M, Paran M, Montaser i S, et al. Compar ing the effects of swaddled bathing methods on body temperature and crying duration in preterm infants: a randomized clinical trial. J Caring Sci. 2014;3(2):83.
41. Engle WA, Tomashek KM and the Committee on Fetus and Newborn of the American Academy of Pediatrics. “Late­preterm” infants: a population at risk. Pediatrics. 2007;120(6):1390.
42. Engorn BM, Kahntroff SL, Frank KM, et al. Perioperative hy­pothermia in neonatal intensive care unit patients: effectiveness of a thermoregulation intervention and associated risk factors. Paediatr Anaesth. 2017;27(2):196.
43. Fenton C, McNinch NL, Bieda A, et al. Clinical outcomes in preterm infants following institution of delayed cord clamping practice change. Adv Neonatal Nurs. 2018;18(3):223.
44. Flenady VJ, Woodgate PG. Radiant warmers versus incubators for regulating body temperature in newborn infants. Cochrane Database Syst Rev. 2003;4:CD000435.
45. Friedrichs J, Staffileno BA, Fogg L, et al. Axillary temperatures in full-term newborn infants. Adv Neonatal Care. 2013;13(5):361.
46. Gaylord MS, Wr ight K, Lorch K, et al. Improved fluid manage­ment utilizing humidified incubators in extremely low birth weight infants. J Perinatal. 2001;21(7):438.
47. Godfrey K, Nativio D, Bender CV, Schlenk EA. Occlusive bags to prevent hypothermia in premature infants: a quality improvement initiative. Adv Neonatal Care. 2013;13(5):311.
48. Gouchon S, Gregori D, Picotto A, et al. Skin-to-skin contact after cesarean delivery: an experimental study. Nurs Res. 2010;59(2):78.
49. Greenspan JS, Cullen AB, Touch SM, et al. Thermal stability and transition studies with a hybrid warming device in neo­nates. J Perinatol. 2001;21(3):167.
50. Haddad L, Smith S, Phillips KD, Heidel RE. Comparison of temporal artery and axillary temperatures in healthy newborns. J Obstet Gynecol Neonatal Nurs. 2012;41(3):383.
51. Handhayanti L, Rustina Y, Budiati T. Differences in tempera­ture changes in premature infants during invasive procedures in incubators and radiant warmers. Compl Child Adolesc Nurs. 2017;40(suppl 1):102.
52. Harer M, Vergales B, Cady T, et al. Implementation of a multidisciplinary guideline improves preterm infant admission temperatures. J Perinatol. 2017;37(11):1242.
53. Henningsson A, Nystrom B, Tunnel R. Bathing or washing babies after birth. Lancet. 1981;19(8260-61):1401.
54. Hsu KH, Chaing MC, Lin SW, et al. Thermal blanket to improve thermoregulation in preterm infants: a randomized controlled trial. Pediatr Crit Care Med. 2015;16(7):637.
55. Hu XJ, Wang L, Zheng RY, et al. Using polyethylene plastic bag to prevent hypothermia in very low birth weight infants: a randomized controlled trial. J Perinatol. 2018;38(4):332.
56. Hylen A, Karlsson E, Svatberg L, et al. Hygiene for the new­born: to bathe or to wash? J Hyg. 1981;91:529.
57. Ibrahim CP, Yoxall CW. Use of plastic bags to prevent hypo­thermia at birth in premature infants: do they work at lower gestations? Acta Paediatr. 2009;98:256.
58. Ibrahim CP, Yoxall CW. Use of self-heating gel mattresses eliminates admission hypothermia in infants born below 28 weeks’ gestation. Eur J Pediatr. 2010;169(2):795.
59. Jensen CF, Ebbesen F, Petersen JP, et al. Hypothermia at neonatal intenisive care unit admission was not associated with respiratory disease or death in very preterm infants. Epub ahead of print. Acta Paediatr. 2017;106(12):1934.
60. Jia YS, Lin ZL, Lv H, et al. Effect of delivery room temperature on the admission temperature of premature infants: a random­ized controlled trial. J Perinatol. 2013;33(4):264.
61. Johannsen JKI, Vochem M, Neuberger P. Does a higher ambient temperature in the delivery room prevent hypothermia in preterm infants < 1500 grams? Z Geburtshilfe Neonatal. 2017;221(5):235.
62. Karlsson V, Heinemann AB, Sjors G, et al. Early skin-to-skin care in extremely preterm infants: thermal balance and care environment. J Pediatr. 2012;161(3):422.
63. Kim SM, Lee EY, Chen J, Ringer SA. Improved care and growth outcomes by using hybrid humidified incubators in very preterm infants. Pediatrics. 2010;125(1):e137.
64. Knobel RB, Wimmer JE, Holbert D. Heat loss prevention for preterm infants in the delivery room. J Perinatol. 2005;25(8):304.
65. Knobel RB, Vohra S, Lehman CU. Heat loss prevention in the delivery room for preterm infants: a national survey of new­born intensive care units. J Perinatol. 2005;25(5):514.
66. Knobel R, Holditch-Davis D. Thermoregulation and heat loss prevention after birth and during neonatal intensive care unit stabilization of extremely low birth weight infants. J Obstet Gynecol Neonatal Nurs. 2007;36(3):280.
67. Knobel-Dail RB, Holditch-Davis D, Sloane R, Guenther BD, Katz LM. Body temperature in premature infants during the first week of life: exploration using infrared thermal imaging. J Therm Biol. 2017;69:118.
68. Lantz B, Ottosson C. Using axillary temperature to ap­proximate rectal temperature in newborns. Acta Paedaitr. 2015;104(8):766.
69. Laptook AR, Bell EF, Shankaran S, et al. and the Generic and Moderate Preterm Subcommittee of the NICHD Neonatal Research Network. Admission temperature and associated mortality and morbidity among moderately and extremely preterm infants. J Pediatr. 2018;192:53.
70. Laptook AR, McDonald SA, Shankaran S, et al. Elevated tem­perature and 6-to-7 year outcome of neonatal encephalopathy. Ann Neurol. 2013;73:520.
71. Laptook AR, Salhab W, Baskar B. Admission temperature of low birth weight infants: predictors and associated morbidities. Pediatrics. 2007;119:6643.
72. Laptook AR, Tyson J, Shankaran S, et al. Elevated temperatures after hypoxic-ischemic encephalopathy: risk factor for adverse outcomes. Pediatrics. 2008;122(4):491.
73. Leadford AE, Warren JB, Manasyan A, et al. Plastic bags for the prevention of hypothermia in preterm and low birth weight infants. Pediatrics. 2013;132(1):e128.
74. Lee G, Flannery-Bergey D, Randall-Rollins K, et al. Accuracy of temporal artery thermometry in neonatal intensive care infants. Adv Neonatal Care. 2011;11(1):62.
75. L’Herault J, Petroff L, Jaffrey J. The effectiveness of a thermal mattress in stabilizing and maintaining body temperature during the transport of very low birth weight newborns. Appl Nurs Res. 2001;14(4):210.
76. Lewis DA, Sanders LP, Brockopp DY. The effect of three nursing interventions on thermoregulation in low birth weight infants. Neonatal Netw. 2011;30(3):160.
CHAPTER 6 Heat Balance
https://t.me/medicina_free
163
77. Lewis LA, Jacobson AF. Electronic health record documentation of nursing care procedures and change in weight of healthy, moderately premature neonates. Neonatal Netw. 2017;36(6):348.
78. Li S, Guo P, Zou Q, et al. Efficacy and safety of plastic wrap for prevention of hypothermia after birth and during NICU in preterm infants: a systematic review and meta-analysis. PLoS One. 2016;11(6):e0156960.
79. Liley HG, Mildenhall L, Morley P, and the Australian and New Zealand Committee on Resuscitation. Neonatal Resuscitation Guidelines 2016. J Paediatr Child Health. 2017;53(7):621.
80. Loring C, Gregory K, Gargan B, et al. Tub bathing improves thermoregulation of the late preterm infant. J Obstet Gynecol Neonatal Nurs. 2012;41(2):171.
81. Ludington-Hoe SM, Lewis T, Morgan K, et al. Breast and infant temperatures with twins during shared kangaroo care. J Obstet Gynecol Neonatal Nurs. 2006;35:223.
82. Ludington-Hoe SM, Morgan K, Abouelfettoh A. A clinical guideline for implementation of kangaroo care with premature infants of 30 or more weeks’ postmenstrual age. Adv Neonatal Care. 2008;8(2):S3.
83. Lyu Y, Shah PS, Ye X Y, et al. Association between admission temperature and mortality and major morbidity in preterm infants born at fewer than 33 weeks’ gestation. JAMA Pediatr. 2015;169(4):e150277.
84. Maastrup R, Greisen G. Extremely preterm infants tolerate skin-to-skin contact during the first weeks of life. Acta Paedaitr. 2010;99(8):1145.
85. Maayan-Metzger A, Yosipovitch G, Hadad E, et al. Effect of radiant warmer on transepidermal water loss (TEWL) and skin hydration in preterm infants. J Perinatol. 2004;24(6):372.
86. Magzub N, Salama H, Albaridi A, Zeed MA, Thampan J. Hu ­midity levels inside newborn incubators used in the neonatal intensive care unit (NICU). Neonatology Today. 2016;11(1):1.
87. Mank A, VanZanten HA, Meyer MP, et al. Hypothermia in preterm infants in the first hours after birth: occurrence, course and risk factors. PLoS One. 2016;11(11):e0164817.
88. McCall EM, Alderdice F, Halliday HL, et al. Interventions to prevent hypothermia at birth in preterm and/or low birth­weight infants. Cochrane Database Syst Rev. 2010;3:CD004210.
89. McCarthy LK, Molloy EJ, Twomey AR, et al. A randomized trial of exothermic mattresses for preterm newborns in poly­ethylene bags. Pediatrics. 2013;132(1):e135.
90. McGrory L, Owen LS, Thio M, et al. A randomized trial of conditioned or unconditioned gases for stabilizing preterm infants at birth. J Pediatr. 2018;193:47.
91. Medoff-Cooper B, Holditch-Davis D, Verklan MT, et al. New­born clinical outcomes of the AWHONN late preterm infant research-based practice project. J Obstet Gynecol Neonatal Nurs. 2012;41(6):774.
92. Mellien A. Incubators versus mothers’ arms: body temperature conservation in very-low-birth-weight premature infants. J Obstet Gynecol Neonatal Nurs. 2001;30(2):157.
93. Meyer MP. Swaddling and heat loss. Arch Dis Child Fetal Neo- natal Ed. 2003;88(3):F256.
94. Meyer MP, Hon D, Ishrar N, et al. Initial respiratory support with cold, dry gas versus heated humidified gas and admission temperature in preterm infants. J Pediatr. 2015;166(2):245.
95. Miller SS, Lee HC, Gould JB. Hypothermia in very low birth weight infants: distribution, risk factors and outcomes. J Perina- tol. 2011;31(suppl 1):S49.
96. Molgat-Seon Y, Daboval T, Chou S, Jay O. Assessing neonatal heat balance and physiologic strain in newborn infants nursed under radiant warmers in intensive care with fentanyl sedation. Eur J Appl Physiol. 2014;114(12):2539.
97. Moore E, Bergman N, Anderson GC, Medley N. Early skin­to-skin contact for mothers and their healthy newborn infants. Cochrane Database Syst Rev. 2016;11:CD003519.
98. Morassutti FR, Cavallin F, Zaramella MD, et al. Association of rewarming rate on neonatal outcomes in extremely low birth weight infants with hypothermia. J Pediatr. 2015;167(3):557.
99. Morehouse D, Williams L, Lloyd C, et al. Perioperative hypo­thermia in NICU infants: its occurrence and impact on infant outcomes. Adv Meonatal Nurs. 2014;14(3):153.
100. Mori R, Khanna R, Pledge D, Nakayama T. Meta-analysis of physiological effects of skin-to-skin contact for newborns and mothers. Pediatr Int. 2010;52(2):161.
101. Motil KJ, Blackburn MG, Pleasure JR, et al. The effects of four different radiant warmer temperature set-points used for rewarming neonates. J Pediatr. 1974;84(4):546.
102. Narendran V, Hoath SB. Thermal management of the low birth weight infant: a cornerstone of neonatology. J Pediatr. 1999;134(5):529.
103. New K, Flenady V, Davies MW. Transfer of preterm infants from incubators to open cot at lower versus higher body weight. Cochrane Database Syst Rev. 2011;9:CD004214.
104. New K, Flint A, Bogossian F, East C, Davies MW. Transferring preterm infants from incubators to open cots at 1600 grams: a multicenter randomized controlled trial. Arch Dis Child Fetal Neonatal Ed. 2012;97(2):F88.
105. Newton T, Watkinson M. Preventing hypothermia at birth in preterm babies: at a cost of overheating some? Arch Dis Child Fetal Neonatal Ed. 2003;88(3):F256.
106. Nimbalkar SM, Patel VK, Patel DV, et al. Effect of early skin­to-skin contact following delivery on incidence of hypother­mia in neonates more than 1800 g: randomized control trial. J Perinatol. 2016;34(5):279.
107. O’brien EA, Colaizy TT, Brumbaugh JE, et al. Body tem­perature of the very low birth weight infants on admission to a neonatal intensive care unit. J Matern Fetal Neonatal Med. 2019;32(16):2763.
108. Olsen K, Koch M. Bundle them up for transport—a quality improvement initiative. Air Medical J. 2016;35(5):279.
109. Park HK, Choi BS, Lee SJ, et al. Practical application of kanga­roo mother care in preterm infants: clinical characteristics and safety of kangaroo mother care. J Perinatal Med. 2014;42(2):239.
110. Philip AG. The evolution of neonatology. Pediatr Res. 2005;58(4):799.
111. Pinheiro JM, Furdon SA, Boynton S, et al. Decreasing hypo­thermia during delivery room stabilization of preterm neonates. Pediatrics. 2014;133(1):e218.
112. Pinheiro JM, Boynton S, Furdon SA, et al. Use of chemical warming packs during resuscitation is associated with decreased rates of hypothermia in very low-birth-weight neonates. Adv Neonatal Care. 2011;11(5):357.
113. Reilly MC, Vohra S, Rac VE, et al. The Vermont Oxford Network Heat Loss Prevention (HeLP) Tr ial Study group. Randomized trial of occlusive wrap for heat loss in preterm infants. J Pediatr. 2015;166(2):262–268.e2.
114. Sarman I, Can G, Tunell R. Providing warmth for preterm babies by a heated water filled mattress. Arch Dis Child. 1989;64 (1 Spec No):29.
115. Schafer D, Boogaart S, Johnson L, et al. Comparison of neo­natal skin sensor temperatures with axillary temperature. Adv Neonatal Care. 2014;14(1):52.
116. Shafie H, Syed Zakaria SZ, Adlie A, et al. Polyethylene versus cotton cap as an adjunct to body wrap and cotton cap. Pediatr Int. 2017;59(7):776.
UNIT TWO Support of the Neonate164
https://t.me/medicina_free
117. Sheldon B. An encapsulated history of thermoregulation in the neonate. Neo Rev. 2004;5:78.
118. Silverman W, Sinclair J, Agate F. The oxygen cost of minor changes in heat balance of small newborn infants. Acta Paediatr Scand. 1966;55(3):294.
119. Silverman W, Agate F. Variation in cold resistance among small newborn animals. Biol Neonate. 1964;6:113.
120. Simon P, Dunnaway D, Bright B, et al. Thermal defense of extremely low gestational age newborns during resuscitation: exo­thermic mattresses vs polyethylene wrap. J Perinatol. 2011;31(1):33.
121. Sinclair JC. Servo-control for maintaining abdominal skin tem­perature at 36° C in low birth weight infants. Cochrane Database Syst Rev. 2002;1:CD001074.
122. Singh A, Duckett J, Newton T, Watkinson M. Improving neonatal unit admission temperatures in preterm babies: exo­thermic mattresses, polyethylene bags or traditional approach? J Perinatol. 2010;30(1):45.
123. Smith J, Alcock G, Usher K. Temperature measurement in the preterm and term neonate: a review of the literature. Neonatal Netw. 2013;32(1):16.
124. Smith J, Usher K, Alcock G, Buettner P. Application of plastic wrap to improve temperatures in infants born less than 30 weeks’ gesta­tion: a randomized controlled trial. Neonatal Netw. 2013;32(4):235.
125. Syrkin-Nikolau ME, Johnson KJ, Colaizy TT, et al. Temporal artery temperature measurement in the neonate. Am J Perinatol. 2017;34(10):1026.
126. Thomas KA. Comparability of infant abdominal skin and axillary temperatures. Newborn Infant Nurs Rev. 2003;3:173.
127. Thomas KA, Magbalot A, Shinabarger K, et al. Seasonal mapping of NICU temperature. Adv Neonatal Care. 2010;10 (5 suppl):83.
128. Toubas PL, Nelson R. The role of the French midwives in establishing the first special care units for sick newborns. J Perinatal. 2002;22(1):75.
129. Trevisanuto D, Coretti I, Doglioni N, et al. Effective tempera­ture under radiant warmer: does the device make a difference? Resuscitation. 2011;82(6):720.
130. Valizadeh L, Mahallei M, Safaiyan A, Ghorbani F, Peyghami M. Comparison of the effect of plastic cover and blanket on body temperature of preterm infants hospitalized in NICU: random­ized controlled trial. J Caring Sci. 2017;6(2):163.
131. Van der Spek RDG, van Lingen RA, van Zoeren-Grobben D. Body temperature measurement in VLBW infants by continuous
skin measurement is a good oe even better alternative than continuous rectal measurement. Acta Paediatr. 2009;98(2):282.
132. Watkinson M. Temperature control of premature infants in the delivery room. Clin Perinatol. 2006;33(1):43.
133. Wilson E, Maier RF, Norman M, et al. Admission hypothermia in very preterm infants and neonatal mortality and morbidity. J Pediatr. 2016;175:61.
134. Wilson E, Zeitlin J, Piedvache A, et al. Cohort study from 11 European countries highlighted differences in the use and efficacy of hypothermia prevention strategies after very preterm birth. Epub ahead of print. Acta Paedaitr. 2018;107(6):958.
135. World Health Organization. Thermal Protection of the Newborn: A Practical Guide; 1997. https://www.who.int/maternal_child_ad-
olescent/documents/ws42097th/en/. Accessed July 22, 2019.
136. YIP WY, Quek BH, Fong MCW, et al. A quality improvement project to reduce hypothermia in preterm infants on admission to the neonatal intensive care unit. Int J Qual Health Care. 2017;29(7):922.
137. Zecca E, Corsello M, Priolo F, et al. Early weaning from incubator and early discharge of preterm infants: randomized clinical trial. Pediatrics. 2010;126(3):e651.
138. Zeitlin J, Manktelow BN, Piedvache A, Cuttini M, Boyle E, et al. Use of evidence-based practices to improve survival with­out severe morbidity for very preterm infants: results from the EPICE population based cohort. BMJ. 2016;354:i2976.
RESOURCES FOR PROFESSIONALS
Bissinger RL. Teaching toolbox: method for wrapping the infant in
occlusive wrap at birth. Adv Neonatal Care. 2010;10(5):239A.
Charpak N, Ruiz J.G. Latin American clinical epidemiology network
series-paper 9: the kangaroo mother care method: from scientific evidence generated in Columbia to worldwide practice. J Clin Epidemiol. 2017;86:125.
Gardner SL. Clinical Practice Tool: NO Rectal Temperatures in the
Newborn Infant: Evidence-Based Nursing Practice (C); 2019. Available at: www.professionaloutreachconsultation.org or at 303-332-4291.
Purnamasari MD, Rustina Y, Waluyanti FT. Heat loss prevention
education aids nurses’ knowledge in prevention of hypothermia in newborns. Compr Child Adolesc Nurs. 2017;40(suppl 1):37.
Raffel D. The Strange Case of Dr. Couney: How a Mysterious European
Showman Saved Thousands of American Babies. New York: Blue Rider Press; 2018.
PHYSIOLOGIC
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7
ignificant advances in the management of the ill preterm infants have been made in the
S
past 70 years. The clinical usefulness of the umbilical vein was first demonstrated by Diamond in 1947 to perform an exchange transfusion to prevent kernicterus. Later, James used the umbilical artery for acid-base determination. In most neonatal intensive care units (NICU), use of these catheters has become the standard of care to assess blood gases, measure arterial and central venous pressures, administer medications and fluids, and obtain labo­ratory samples. The development of small, indwell­ing, peripherally inserted central catheters provides a route for administering the aforementioned items and may be used for laboratory sample withdrawal if no other method of obtaining blood is available. The frequency and clinical significance of compli­cations and alternatives to these intravascular routes have been vigorously sought. The development of noninvasive physiologic monitoring devices has been a major step toward this goal. In addition, the use of point-of-care testing for various laboratory values is evolving in neonatal care. This chapter reviews the procedures and advances in physiologic monitoring.
MONITORING
KRISTI COE, WANDA T. BRADSHAW, AND DAVID T. TANAKA
PHYSIOLOGY
Pulmonary Physiology
Gas exchange takes place in the alveoli of the lung. Ventilation is the movement of air into and out of these airspaces. Diffusion is the movement
of oxygen (O2) from the alveolar space into the pulmonary capillary and the movement of carbon dioxide (CO2) from the pulmonary capillary into the alveolar space for eventual exhalation. Pulmonary
perfusion is the flow of blood through the pulmo­nary capillaries that surround the alveolar spaces.
Once oxygen diffuses through the cells lining the alveoli and into the capillaries, it is predominate­ly bound to hemoglobin within the red blood cell. Oxygen content in the arterial blood is the sum
of the amount of oxygen dissolved in the plasma and the amount bound to hemoglobin. Approximately
3% of the oxygen content is dissolved in the plasma, with the remaining 97% bound to hemoglobin. PaO2 is the partial pressure of the
oxygen dissolved in arterial plasma. Fetal hemoglobin
has a higher affinity for oxygen than does adult hemoglobin; therefore, at any given PaO2, more oxygen is bound to fetal hemoglobin (Fig. 7.1). Each hemoglobin molecule can carry four oxy­gen molecules. Oxygen saturation (SaO2) is the percentage of oxygen bound to hemoglobin.
Carbon dioxide content in arterial blood is
the sum of the amount of carbon dioxide in the plasma plus the amount bound to hemoglobin. As
hemoglobin gives up oxygen to the tissues, it is able to pick up carbon dioxide. Each reduced hemoglo-
bin molecule can carry four carbon dioxide mol­ecules, thus lowering the free hydrogen ion (H+) concentration. Approximately 10% of the carbon
dioxide content is gas dissolved in the plasma (CO2), 60% is carbonic acid (H2CO3), and the remaining 30% is attached to proteins, predominantly hemo­globin. PaCO2 is the partial pressure of carbon
dioxide dissolved in arterial blood. It is a measured
value that denotes the partial pressure of arterial car­bon dioxide. Carbon dioxide values fluctuate as
needed to maintain the hydrogen ion concentra­tion, or pH, within a normal range. Carbon diox-
ide combines reversibly with water to yield hydrogen (H+) and bicarbonate (HCO CO2 + H2O ↔ H2CO3 ↔ H+ + HCO
–
) ions. The formula is
3
–
.
3
BLUE type highlights content that is particularly applicable to clinical settings.
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% O
Hgb saturation
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0
Fetal Hgb
Adult Hgb
20 40
60 80 100
PO
(mm Hg)
2
100
80
60
2
40
20
0
FIGURE 7.1 Oxygen dissociation curves for fetal hemoglobin (Hgb) (left)
and adult hemoglobin (right).
NONINVASIVE MONITORING
Use of noninvasive technologies to monitor all neonates in the NICU is the standard of care. Many neonates also require invasive monitoring devices.
Oxygen and Carbon Dioxide
OXYGEN
Noninvasive monitoring of oxygenation can be accomplished by using three monitoring technolo­gies, pulse oximetry, transcutaneous oxygen monitoring, and
near-infrared spectroscopy. Oxygen saturation monitoring
is the most common and widely used method for assessing oxygenation status. Transmission tech-
nology relies on a pulsating arterial vascular bed between a dual light source and a photoreceptor. As blood passes between the light source and the photoreceptor, different amounts of red and infra­red light are absorbed, depending on the amount of oxyhemoglobin and reduced hemoglobin. With reflectance oximetry, the emitter and receptor are located beside each other. Emitted light is reflect­ed back to the photoreceptor. This method uses the core body to obtain oxygen saturation and is useful when the patient’s peripheral blood flow is diminished. With this method, the difference in
light absorption is electronically processed and displayed by the monitor as the percentage of
arterial hemoglobin oxygen saturation expressed as SpO2. Pulse oximetry probes are easy to apply and require no warm-up period, calibra­tion, or application of heat.
The second method of noninvasive monitor-
ing of oxygenation is transcutaneous oxygen tension,
which relies on the principle of oxygen diffusing from the skin capillaries through the dermis to the surface of the skin. To measure oxygen diffu-
sion, it is necessary to have adequate perfusion of the site, to intermittently calibrate the sensor, and to heat the skin, which then dilates the local capillaries and arterializes the capillary bed, as well as promotes faster diffusion of the oxygen from the skin.
36
Near-infrared spectroscopy (NIRS) is a newer
method of noninvasive oxygenation measure­ment in the NICU. NIRS was launched in 1977 to
assess cerebral oxygenation and perfusion during car­diac and neurosurgery, but its use has been expanded into neonates, initially used peri- and postoperatively for cardiac surgery.46 This technology is based on tissue transparency to light in the 700- to 1000-nm wavelength, referred to as the near-infrared spectrum. Through a light-emitting diode (LED), NIRS releas­es two wavelengths of near-infrared light signals to maximize separation of the absorbed spectra among oxyhemoglobin and deoxyhemoglobin. The NIRS probe also contains two optodes to receive the scat­tered light, one from peripheral tissue and another from peripheral and deep tissues. After the peripheral value is subtracted from the other value, a tissue-spe­cific regional oxygen saturation (RSO2) value from a 1- to 2-cm depth is attained. In comparison with earlier technology, NIRS signifies tissue oxygen
supply and utilization, while oxygen saturation monitoring suggests (arterial) oxygen supply to tissues. While NIRS was initially used to assess cere-
bral oxygenation and demand by placing the adhesive probe horizontally across the forehead, use has been expanded to deeper organs including the kidneys and intestines because of a superficial location in this age group.
CARBON DIOXIDE
46
Carbon dioxide also can be assessed using two different devices, transcutaneous carbon dioxide and
end-tidal carbon dioxide monitors. Transcutaneous car- bon dioxide (PtcCO2) monitoring works under
similar principles as for transcutaneous oxygen monitoring.34 The probe is a glass pH electrode
CHAPTER 7 Physiologic Monitoring
AB
CO
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167
2
38 mm Hg
C
0
FIGURE 7.2 Variations in the content of carbon dioxide during phases of
the respiratory cycle. A, End of inspiration. B, Beginning of exhalation. C, End of mixed gases washout (dead space and alveolar gases). D, End of expiration of alveolar gases. E, Inspiration.
D
E
that detects changes in pH caused by CO2. Heating of the probe enhances CO2 diffusion, providing a better correlation between the probe value and the PaCO2 value. The second method used to measure the content of the carbon dioxide in the respiratory gases during the respiratory cycle is end-tidal carbon dioxide (PetCO2) monitoring, also called capnometry.
With capnometry, an infrared light absorption determines the amount of CO2 present in the sample. Capnography provides a visual graphic curve of PetCO2. The carbon dioxide content
varies widely with the phase of the respiratory cycle. During inspiration, there are minimal amounts of carbon dioxide, whereas at the end of expiration, the carbon dioxide values are at their maximum level (Fig. 7.2). Until recently, the relatively fast respiratory rate of newborns, combined with the small tidal volumes, resulted in inaccurate values when measured by end-tidal carbon dioxide mon­itors. Advances in technology have improved the reliability of this monitoring technique for new­born infants.
COMBINED OXYGEN–CARBON DIOXIDE MONITORING
SpO2/PtcCO2 sensors combining pulse oximetry and transcutaneous carbon dioxide monitoring have been developed. The heated sensor is attached to the patient’s ear. It provides rapid SpO2 values followed by carbon dioxide information within minutes as the site is warmed and arterialized.
A single probe, designed to withstand motion artifact and low perfusion states, leads from the patient to the monitor. The probe is attached to the ear, thus its removal for chest radiographs or prone positioning is not necessary. Studies on normal adults, infants, and very-low-birth-weight (VLBW) infants have shown acceptable correlation with both invasive and noninvasive monitoring techniques for oxygen. Carbon dioxide values were less reliable but allowed trending of ventila­tion status.
38
Amplitude Integrated
Electroencephalography
Although the gold standard for monitoring cerebral
activity in neonates is continuous electroencephalog­raphy (cEEG), a tool that is complementary, ampli­tude-integrated electroencephalography (aEEG), is now used in many NICUs. Infants appropriate
for use of aEEG may include those with clini­cally evident seizure activity or those with seizure activity who have experienced a perinatal hypoxic event.38 Feasibility is likely improved with aEEG
because this technology requires only four electrodes compared with many more channels needed for cEEG. Like other complementary tools, aEEG provides trends over time that allow clinicians to view and assess for abnormal cerebral activity allowing for prompt treatment.
38
Cardiorespiratory Monitoring
The electrical activity of an infant’s heart is picked
up by chest leads (usually three) placed on the infant and recorded by a cardiorespiratory monitor. The recording is displayed on a visual screen as the infant’s electrocardiographic pattern. The infant’s respiratory pattern also is recorded, because the chest leads electronically detect movement of the chest with each respiration.
Blood Pressure Monitoring
Systolic blood pressure, measured in millimeters of mercury (mm Hg), is the pressure at the height of the arterial pulse and coincides with left ventricular systole. Diastolic blood pressure, also measured in mm Hg, is the lowest point of the arterial pulse and coincides with left ventricular diastole. Pulse pressure is the difference between
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the systolic and diastolic blood pressure. Mean arterial pressure is the diastolic pressure plus one-
third of the pulse pressure. Central venous pressure is the pressure in the right atrium and may be approximated by the blood pressure (volume) in any of the large central veins.
Point-of-Care Testing
Point-of-care testing (POCT) involves testing performed at or near the patient rather than in a laboratory. This process has steadily evolved from
crude blood glucose determinations to numerous types of monitoring. Currently, whole-blood glu­cose values, transcutaneous bilirubin, fecal occult blood, gastric pH, urine dipstick, activated clotting time, hematocrit, some electrolyte values, and arte­rial blood gases are part of POCT for the neonatal population.
DATA COLLECTION
The indications for using the various techniques for
physiologic data collection depend on the infant’s clinical situation.
Noninvasive Oxygen and Carbon Dioxide Monitoring
Oxygen monitoring is indicated in infants receiving oxygen for any reason (see Chapter
23). Acute monitoring is used as a part of
the management of acute respiratory disorders. Long-term monitoring is used to wean infants with chronic lung disease from oxygen therapy. Noninvasive oxygen monitoring is useful during transport, in emergency situations, and during procedures. However, this method provides no information on hemoglobin level, adequacy of ventilation, and oxygen delivery to the tissues and should be used as one part of total oxygenation and ventilation assessment. Despite how oxygen saturation monitoring is used more, less vari­ability in oxygen tension has been demonstrated when transcutaneous oxygen monitoring has been employed.
Carbon dioxide monitoring is useful for veri­fying that the endotracheal tube is in the trachea (end-tidal CO2 monitoring) and for the infant with a respiratory disease in whom retention of carbon
36
dioxide may become clinically significant (end-tidal CO2 and transcutaneous CO2 monitoring).
Cardiorespiratory Monitoring
Cardiorespiratory monitoring should be used in all infants who require intensive or intermediate care, as well as in all infants at risk for apnea or rhythm disturbances.
Blood Pressure Monitoring
Blood pressure monitoring should be used in the infant requiring surgery, in the acutely ill infant with cardiorespiratory distress, and in any other illness in which hypotension may be a significant contributor to the pathologic state.
Central venous pressure should be monitored in infants who may experience an excess or loss of blood volume.
Umbilical Artery Catheters
An umbilical artery catheter (UAC) is placed in those infants requiring frequent arterial blood gas determinations, continuous monitoring of arterial blood pressure, and infusion of paren­teral fluids. The practice of medication adminis-
tration through a UAC varies, although there are no published data in the past decade regarding this practice. ing catheters include critically ill neonates and those with congenital heart disease or disorders that cause respiratory insufficiency (e.g., surfactant defi­ciency, meconium aspiration syndrome, persistent pulmonary hypertension, diaphragmatic hernia).
Although use of an indwelling UAC allows arterial pressure monitoring and accessibility for parenteral infusions, it is generally not used for these indications alone.
31,45
Infants who are candidates for indwell-
Umbilical Vein Catheters
Umbilical vein catheters (UVCs) are useful for exchange transfusions, central venous pressure monitoring, emergency administration of fluids or chemicals in delivery room resuscitation, and administration of parenteral fluids and medications in the NICU, as well as obtaining blood for laboratory analysis. UVCs are used
with increasing frequency for initial management