1、Neonatal Asphyxia and Resuscitation The first affiliated hospital of xinxiang medical university NICU,Clinical Example,You are asked to attend an emergent cesarean section delivery of a 40 weeks gestation infant with non-reassuring heart tones. Mother is a 30-year old gravida I married woman who was

2、 admitted in active labor four hours ago. Membranes are ruptured at the time of delivery revealing bloody amniotic fiuid but no meconium. At 30 seconds of life, he remains apneic and cyanotic. His heart rate is 30 beats per minute. You administer positive pressure ventilation with 100% FiO2, and not

3、e good chest wall rise with each positive pressure breath. The infant continues to be apneic and bradycardic with a heart rate of 40 bpm. Chest compressions are begun and positive pressure ventilation is continued. Following 30 seconds of coordinated ventilation and chest compressions, his heart rat

4、e is still 40 bpm. You intubate the infant while the nurse draws up epinephrine to be given via the endotracheal tube. There is no improvement in his heart rate following administration of epinephrine. The infant remains bradycardic. reassess Positive pressure ventilation and chest compressions are

5、continued as you the infant. Good breath sounds are heard bilaterally, but his skin remains pale and mottled and pulses are difficult to palate.,Definition Pathophysiology Evaluation of the Newly Born Infant Resuscitation Resuscitation Program algorithm,Study Highlights,Definition,Neonatal asphyxia

6、is mainly due to failure of the newborn to breathe after birth, or its heart fails to pump enough blood to the lungs for gas exchange, or it has low haemoglobin levels (anaemia) so it cannot deliver enough oxygen around the body. The baby who cannot breathe cannot establish independent life outside

7、the mother. Therefore, the purpose of neonatal resuscitation is to help the newborn to establish spontaneous breathing and facilitate oxygen delivery to its organs and tissuesparticularly the brain, which is very quickly damaged by oxygen shortage. You may also need to resuscitate any baby that is s

8、everely anaemic due to blood loss during labour and delivery, or that continues to be cyanotic despite established breathing.,Pathophysiology,During labor, the fetus experiences brief periods of ischemia and hypoxemia because with each uterine contraction, flow to the placenta(胎盤) decreases transien

9、tly, impairing placental gas exchange. However, the fetus is able to recover between each contraction and blood gases performed in the umbilical cord(臍帶) immediately after birth are within a normal” range. Overstimulation of the uterus with oxytocin(催產(chǎn)素) may lead to excessively frequent contractions

10、 with limited recovery time and thereby compromise fetal well-being.,Pathophysiology,To achieve successful transition to extrauterine life, the infant must accomplish dramatic cardiorespiratory changes. In the first minutes after cord clamping, with the initiation of breathing, lungs must be expande

11、d and fluid inside the alveoliand airways must be rapidly absorbed. Pulmonary blood flow must increase dramatically, and intracardiac and extracardiac shunts initially reverse direction and subsequently close. The first breaths of a normal-term neonate exert negative pressures that may reach pressur

12、es as high as 80 cmH2O.,Evaluation of the Newly Born Infant,The assessment of the newborns postnatal adaptation in the delivery roomis usually done using the Apgar score, which evaluates five clinical signs: heart rate, respiratory effort, color, tone, and response to stimuli at 1 and 5 min.,Evaluat

13、ion of the Newly Born Infant,The Apgar score for evaluation of adaptation of the newborn infant after birth,The higher the score, the better the baby is doing after birth.A score of 7, 8, or 9 is normal and is a sign that the newborn is in good health. A score of 10 is very unusual, since almost all

14、 newborns lose 1 point for blue hands and feet, which is normal for after birth.Any score lower than 7 is a sign that the baby needs medical attention. The lower the score, the more help the baby needs to adjust outside the mothers womb.,Evaluation of the Newly Born Infant,An apneic infant should sc

15、ore “0”, even if the infant is ventilated. Inadequate respiratory efforts should score “1”, also if the infant is ventilated. The premature infant that is hypotonic scores “1 for muscle tone. Heart rate(HR) is the most relevant clinical sign indicating adequate postnatal adaptation and/or response t

16、o resuscitation. In addition, HR in the first minutes of life has prognostic value regarding mortality in the early neonatal period. Assessment of the color also shows high interobserver variability, especially in preterm infants. This can be avoided with the use of pulse oximetry(脈搏血氧儀). It is impo

17、rtant to understand that healthy-term newborns do not reach preductal(導(dǎo)管前) oxygen saturations(血氧飽和度) greater than 85-90% until 5 min and preterm infants not until 10-15 min after birth.,Evaluation of the Newly Born Infant,Newborns moving their extremities soon after birth do not require any assistan

18、ce. However, if these responses are absent or weak, stimulation by rubbing the back with a dry soft towel should suffice. Other methods such as slapping, foot flicking, shaking, spanking, or holding the baby upside down are potentially dangerous and should not be used. If the infant does not respond

19、 promptly, PPV should be started. An infant with good tone is unlikely to be severely compromised, whereas a floppy infant is likely to need active resuscitation. However, as indicated above, special attention should be paid especially very premature infants for whom a hypotonic state is physiologic

20、.,Resuscitation,Suctioning. Positive-pressure ventilation. Term infant with perinatal asphyxia. Preterm infant with perinatal asphyxia. Cardiac resuscitation. Drugs used in resuscitation. Medications commonly used in neonatal resuscitation. Temperature regulation.,Resuscitation-Suctioning,Oropharyng

21、eal and nasal secretions should be partially removed with a brief period of suctioning using either a bulb syringe or a suction catheter if there are signs of airway obstruction or before initiation of positive-pressure ventilation.,Resuscitation-Positive-pressure ventilation(PPV),Most infants can b

22、e adequately ventilated with a bag and mask provided that the mask is the correct size with a close seal around the mouth and nose, and there is an appropriate flow of gas to the bag. A T-piece resuscitator is an alternative method to provide positive-pressure ventilation that controls peak pressure

23、 and positive end-expiratory pressure(PEEP, 呼氣末正壓), or continuous positive airway pressure(CPAP, 持續(xù)氣道正壓通氣). Respiratory rate should be 40-60 breaths/min, or 30 breaths/min if accompanying chest compressions. Peak pressures of 20-25 cmH2O are usually sufficient.,a bag and mask,Resuscitation-Term infa

24、nt with perinatal asphyxia,Initially all infants without meconium-stained amniotic fluid should be dried and have their oropharynx suctioned. A term infant with a heart rate of 100 beats/min or no spontaneous respiratory activity requires intubation and positive pressure ventilation.,Method of endot

25、racheal intubation in neonatal resuscitation,Resuscitation-Preterm infant with perinatal asphyxia,Preterm infants weighing 1200 g often require immediate lung expansion in the delivery room. Mask continuous positive airway pressure( CPAP), administered with a T-piece resuscitator or a flow-inflating

26、 bag-and-mask system, providing a pressure of 4-6 cm water, may be sufficient to expand the lungs of a preterm infant and improve ventilation.,Resuscitation-Cardiac resuscitation,During delivery room resuscitation, efforts should be directed first to assisting ventilation and providing supplemental

27、oxygen. A sluggish heart rate usually responds to these efforts.,Resuscitation-Drugs used in resuscitation,The Textbook of Neonatal Resuscitation, 6th ed, recommends giving medications if the heart rate remains 60 beats/min despite adequate ventilation and chest compression for a minimum of 30 secon

28、ds. Route of administration The umbilical vein(臍靜脈). The endotracheal tube Alternate routes: peripheralprf()r()l venous, intraosseous(骨內(nèi)).,Resuscitation-Medications,Medications commonly used in neonatal resuscitation Epinephrine ,epnefrn腎上腺素 Volume expanders 擴(kuò)容劑 Naloxone nlksn納洛酮 Sodium bicarbonate

29、bakrbnt碳酸氫鈉 Atropine trpin阿托品 and calcium Other supportive measures,Resuscitation-Temperature regulation,Although some degree of cooling in a newborn infant is desirable because it provides a normal stimulus to respiratory effort, excessive cooling increases oxygen consumption and exacerbates acidos

30、is. This is a problem especially for preterm infants, who have thin skin, decreased stores of body fat, and increased body surface area. Heat loss may be prevented by the following measures.,American Academy of Pediatrics Neonatal Resuscitation Program algorithm.,Resuscitation Program algorithm,Thos

31、e newly born infants who do not require resuscitation can generally be identified by a rapid assessment of the following 3 characteristics: Term gestation? Crying or breathing? Good muscle tone? If the answer to all 3 of these questions is “yes,” the baby does not need resuscitation and should not b

32、e separated from the mother. The baby should be dried, placed skin-to-skin with the mother, and covered with dry linen to maintain temperature. Observation of breathing, activity, and color should be ongoing.,Resuscitation Program algorithm,If the answer to any of these assessment questions is “no,” the infant should receive one or more of the following 4 categories of action in sequ