Newborn: Apnea, Hypothermia and Hyperthermia Dr. Kalpana Malla MD Pediatrics Manipal Teaching HospitalDownload more documents and slide shows on The Medical Post [ www.themedicalpost.net ]
CONTENTS• Apnea and its types.• Hypothermia• Hyperthermia
APNEADEFINITION• Cessation of breathing for longer than 20sec, or any duration if accompanied by cyanosis and sinus bradycardia
APNEA AND TYPES• Common in preterm infants : Idiopathic apnea of prematurity• Associated illness• Periodic breathing• Central apnea• Obstructive apnea• Mixed apnea
OBSTRUCTIVE APNEA• Absence of identifiable predisposing diseases• Pharyngeal instability• Neck flexion• Nasal occlusion• Characterized by absent airflow but persistent chest wall motion• Pharyngeal collapse may follow the negative airway pressures generated during inspiration, or it may result from incoordination of the tongue and other upper airway muscles involved in maintaining airway patency
CENTRAL APNEA• Decreased central nervous system (CNS) stimuli to respiratory muscles, airflow and chest wall motion are absent
IDIOPATHIC APNEA OF PREMATURITY• Mixed etiology (50–75%)• Obstructive apnea preceding (usually) or following central apnea• Short episodes of apnea are usually central, whereas prolonged ones are often mixed.• Apnea is sleep state dependent• Frequency increases during active (rapid eye movement) sleep• Paradoxical chest wall movement (inspiratory abdominal expansion and inward chest wall movement) is common during active sleep and may cause a fall in Pao2 because of ventilation-perfusion defects• Inhibition of pharyngeal muscle tone during active sleep may contribute to upper airway collapse and obstructive apnea.
CLINICAL MANIFESTATIONS• The incidence of idiopathic apnea of prematurity varies inversely with gestational age• preterm : rare on the D1, occurs on D2–D7• Cessation of breathing• Bradycardia• Cyanosis• Apnea of prematurity usually resolves by 36 wk postconceptional age
TREATMENT• Gentle cutaneous stimulation :mild and intermittent episodes• immediate bag and mask ventilation : recurrent and prolonged apnea• Oxygen• Methylxanthines(theophylline or caffeine) enhance ventilation through a central mechanism or by improving diaphragmatic strength.
TREATMENT (CONTD…)• Loading doses of 5mg/kg of theophylline (orally) or aminophylline (intravenously) - followed by doses of 1–2mg/kg given every 6– 8hr by the oral or intravenous routes• Loading doses of 10mg/kg of caffeine - followed 24hr later by maintenance doses of 2.5mg/kg/24hr qd orally.• Therapeutic levels: theophylline: 6–10µg/mL; caffeine: 8–20µg/mL
TREATMENT (CONTD…)• Transfusion of packed red blood cells• Treat gastroesophageal reflux :antireflux medications controversial• Nasal continuous positive airway pressure (CPAP)• Continuous positive pressure splints the upper airway and thereby prevents obstruction.• Neck extension with a shoulder pad
Introduction• After birth, skin temperature falls by 0.3 C/min and core temperature by 0.1 C/min.• 15% of NB develop hypothermia in developing countries.
Neonatal Considerations• Relative to body wt, BSA of NB 3 times higher than that of adult.• LBW insulating layer of s/c fat lesser.• Preterms have less developed stores of brown fat.
Neonatal Consideratios• Underdeveloped shivering & sweating mechanisms.• Limited calorie intake to provide nutrients for thermogenesis.• Inability to maintain flexed posture in PT to reduce effective surface area.
Response To Cold• Metabolic thermogenesis- Fetal brown fat laid down in 3rd trimester, neck, interscapular, axilla, groin, kid ney & adrenals. Local release of noradrenaline-TG oxidised to glycerol & fattyacids-heat.
Loss Of Heat• Radiation-heat dissipates from infant to colder object in environment. Eg wall, window.• Conduction-heat loss from infant to surface on which baby lies.• Convection- loss from skin to moving air.• Evaporation-imply loss of heat by moisture vaporising from skin surface.
Hypothermia• Recording of temperature – Rectal, Axilla, Skin• Skin temperature <35.5 C• Core temperature <36 C• Etiology -excessive heat loss -inability to conserve heat -poor metabolic heat production
Severity of hypothermia• Cold stress- core temperature 36 C- 35.5 C• Moderate hypothermia 32 C-35.9 C• Severe hypothermia <32 C
How To Keep Babies Warm• Labour room- prewarmed room, radiant heat source, immediate drying, skin to skin contact with mother, early breast feeding, delay bath. LBW/PT-transfer to NICU ideally in transport incubator.• Lying in a ward- next to mother, adequate clothing, saps, sponging/bath.
How To Keep Babies Warm• Nursery- environ temp maintained at 26 degree C. Prewarm all surfaces in contact with baby. Perspex heat shield, liquid paraffin. Incubator/Open care has manual and servo control modes.
How To Keep Babies Warm• Operation theatre-cold ambient environ, prewarm IV fluids & anesthetic gases, continuous temp monitoring. Humidified oxygen.• Transport- Uterus ideal transport incubator! Well covered, skin to skin contact. Thermocole box with hot water bottles.• Home care- Cot away from walls, contact with mother, train to assess temperature, Oil massage
KANGAROO MOTHER CARE• Kangaroo Mother Care• Biologically controlled heat source• Ventral surface of baby in contact with mother’s boson• Dorsal surface covered with clothes• Poor cultural acceptability in our society
Prevention of Hypothermia• Identification of high risk mother• Create warm micro-environment to welcome the baby• Delay bath• Maintain NICU at 26 degree Celsius• Standby incubator ready• Babies effectively clothed• Special care to prevent Hypothermia during transport and Procedures
Prevention of Hypothermia• Application of Oil and Liquid paraffin can reduce evaporation from skin• Skin to skin contact• Educate mother and health workers
HYPERTHERMIA• Common in tropical country.• Sunlight exposure for jaundice.• Iatrogenic hypothermia.• PT below 32 wks do not sweat.• Transient fever of newborn- raised environ temp, immaturity of heat regulating centre, inefficient sweating.
Thank youDownload more documents and slide shows on The Medical Post [ www.themedicalpost.net ]