- Jul 20th, 2015
- Geoff Jara-Almonte
Neonatal Resuscitation Highlights
Author: Geoff Jara-Almonte, MD (PEM Fellow, NY Methodist Hospital) // Edited by: Jennifer Robertson, MD and Alex Koyfman, MD (@EMHighAK)
You are midway through an overnight shift in a suburban emergency department (ED) when a young woman is dropped off by her partner in labor. The triage nurse brings her to an exam room and she is placed on the cardiac monitor. Her vital signs are a temperature of 38.5° Celsius (C), a heart rate (HR) of 123, and a blood pressure (BP) of 110 /67 mm Hg. Between contractions, the patient tells you that this is her 4th pregnancy, is approximately 8 or 9 months pregnant and that she has not had any prenatal care. She also tells you that all of her prior deliveries were “fast”. As you try to decide what to do next, the patient has another contraction and feels an unbearable urge to push. You see the fetal head at the perineum, and note thick meconium-stained amniotic fluid. You realize that the infant is likely distressed and may require resuscitation. You try to recall the general priorities of neonatal resuscitation.
Most infants transition from intrauterine to extrauterine life without any assistance. The term-infant with good tone, color, and respiratory effort requires no assistance and should be handed off to the mother after birth.
However, approximately 10% of infants require some resuscitation and about 1% require extensive resuscitation. The main priority in neonatal resuscitation is establishment of effective ventilation and oxygenation. The first step is an initial trial of basic supportive measures including cleaning, drying and stimulating the infant. If there is poor tone or respiratory effort, try stimulating by gently slapping the feet. If there is airway obstruction, attempt repositioning – place the infant in the “sniffing” position. If the airway obstruction is due to secretions, attempt gentle suctioning with bulb suction or a soft suction catheter.
Heat loss should also be minimized. Infants should be dried quickly and wet blankets or towels discarded. Vigorous infants who require no resuscitation should be swaddled in warm dry blankets or placed directly on the mother’s skin. If resuscitation is required, the infant should be placed in an isolette under a radiant warmer. Low birth weight infants are at a greater risk of hypothermia. Those infants less than 1,500 grams (gm) should be wrapped in medical or food grade plastic bag to prevent evaporative cooling.
As your nurse pulls out the precipitous delivery pack, you prepare for the delivery by turning on the radiant warmer and connecting the suction and supplemental oxygen. Soon, with a final contraction, a male infant is delivered. You estimate that he weighs about 3.5 kilograms (kg), and appears near term. However, you also notice that he is meconium stained and is cyanotic with minimal respiratory effort. You realize that this meconium stained neonate is going to require resuscitation.
Aspiration of any amount of meconium-stained amniotic fluid, whether intrauterine, intra-partum or post-partum can lead to the development of meconium aspiration syndrome (MAS). Fortunately this syndrome complicates only 2 to 5% of meconium births. The severity can range from mild tachypnea to severe pneumonitis. In order to reduce the risk of MAS, older guidelines advocated routine intrapartum suctioning between delivery of the head and shoulders, but this practice has been shown to be ineffective. Routine intubation and endotracheal suctioning of all infants with thick meconium was historically recommended as well, however this has been shown to be ineffective and is no longer standard practice.
Current management of the infant born with meconium-stained amniotic fluid depends on the clinical status of the child. A vigorous infant can be managed with supportive care and oral and nasal suctioning, if indicated. Non-vigorous infants should have endotracheal suctioning performed prior to other resuscitative measures. To perform endotracheal suctioning, a meconium aspirator is attached to suction and an endotracheal tube. The infant is then intubated with direct laryngoscopy. Next, the vent port on the meconium aspirator is occluded and the endotracheal tube is slowly withdrawn. The used tube is then switched for a clean one, the infant is re-intubated, and the process is repeated. The procedure is repeated until clear secretions are aspirated. If there is a significant delay in or difficulty intubating the infant, consider omitting this step and proceeding to positive pressure ventilation (PPV), especially if there is persistent bradycardia.
You quickly hook the meconium aspirator to wall suction and attach the other end to the endotracheal tube. You carefully advance the laryngoscope, lift the epiglottis and see the cords. You easily pass the tube. You occlude the suction port on the meconium aspirator and slowly withdraw the tube that contains thick secretions. You leave the blade in place have your nurse quickly replace the tube and perform a second round of tracheal suctioning. This time you have only scant secretions in the tube. You decide that no additional suction is needed. You quickly dry the infant and discard the wet towels. You palpate his pulse at the umbilical stump and note a heart rate of only 50 beats per minute (bpm) and ineffective gasping respirations. You try and decide what the next step should be.
The American Heart Association (AHA) and Neonatal Resuscitation Program (NRP) algorithms allow only 30 seconds to perform the basic supportive measures discussed above. In the case of a non-vigorous meconium-stained infant, basic measures are skipped in favor of immediate endotracheal suctioning. Importantly, bradycardia (HR < 100 bpm) or cyanosis that persists after any step requires the initiation of positive pressure ventilation. Those infants with adequate respiratory effort and heart rate who remain persistently cyanotic should be given supplemental O2 and placed on the pulse oximetry (SpO2) monitor. The SpO2 probe should be placed on the right upper extremity to obtain a pre-ductal value. It is usually placed on the thenar eminence. Placing the probe on the child prior to turning on the monitor may facilitate a more rapid signal acquisition.
Controversy exists regarding the concentration of oxygen to use during initial attempts at PPV. While the dangers of hypoxia are well known, hyperoxia – even for a short period of time – can also have deleterious consequences. Studies have shown lower mortality in infants who are initially resuscitated on room air as compared to 100% fraction of inspired oxygen (FiO2.) The AHA guidelines recommend starting resuscitation with room air or blended oxygen and titrating to maintain a SpO2 in the normal range for post-natal age. If after 90 seconds of resuscitation there is persistent bradycardia, increase the FiO2 to 100%.
PPV should be delivered with an appropriately sized infant bag. Using the larger child-sized bag will increase the likelihood of delivering excessive volume with resultant risk of volutrauma. The initial breath may require relatively high pressures, up to 40 mmHg to adequately open collapsed alveoli. Subsequent breaths should be given with lower peak pressures between 15 and 20 mmHg. Many infant bags have a pop-off valve that prevents delivery of peak pressures greater than 40 mmHg, which helps prevent higher pressures in subsequent breaths. However, in cases of preterm infants with little surfactant and poor pulmonary compliance, higher peak pressures may be needed. For these cases, the pop-off valve may need to be disabled. If pressure monitoring is not available, titrate pressures to adequate chest rise and heart rate.
You grab the infant ambu-bag and start ventilations. You initially attempt positive pressure ventilation alone without supplemental oxygen. You carefully seal the mask over the infant’s face and make sure his airway is well positioned. You feel a little resistance with the first two breaths, but you then note good chest rise. Your nurse places a pulse-oximetry probe and it shows HR of 52 bpm and a SpO2 of 50% with a good waveform.
After 30 seconds of PPV, the infant should again be reassessed for effectiveness of ventilation and heart rate. If the heart rate remains less than 60 bpm after 30 seconds of effective PPV, then chest compressions should be started. Bradycardia and asystole in infants are usually the result of hypoxia. Thus, the first priority is establishing effective ventilation. Compressions should be initiated only after ventilations alone have proved ineffective. The most effective technique for compressions is the two thumb technique. In this technique, the rescuer encircles the infant’s chest with his or her hands and uses two thumbs to compress the sternum. If access is needed to the lower body to place an umbilical vein catheter, then chest compressions can be performed by a provider standing to the infant’s side using two fingers to compress the sternum and a second hand supporting the back. To maximize time allocated for ventilations, chest compressions and ventilations should be alternated in a 3:1 ratio with a goal of 90 compressions and 30 breaths per minute, as per NRP guidelines. Compression rate should be at 100 per minute.
Endotracheal intubation should be performed for any child requiring chest compressions. Intubation may also be needed for those infants in whom it is impossible to achieve effective positive-pressure ventilation, if a prolonged course of positive pressure ventilation is anticipated, or in premature infants who require surfactant. Selection of appropriately sized equipment is critical for maximizing the chance of success at intubation.
You open the wall oxygen flow valve all the way, and call over your ED technician to begin compressions and bagging at a 3:1 ratio. Your nurse obtains a clean endotracheal tube, and you briefly pause compressions to intubate the patient. You confirm tube placement with bilateral breath sounds and colorimetric carbon dioxide (CO2) detector color change. You secure the tube and have your nurse take over bagging. After another minute of bagging and chest compressions, you check again and see that the infant’s heart rate has improved to 85 and his SpO2 has improved to 72%. You tell your tech to stop compressions. After another minute of ventilation with 100% oxygen his sats improve to the low 90s and his heart rate comes up to the 130s. You place him on the ventilator, and call the nearest neonatal intensive care unit (NICU) to arrange transport. Your nurse asks you why you did not give any drugs during the resuscitation, and also asks how you would have obtained intravenous (IV) access.
Drugs are rarely required in the resuscitation of newborn. As previously mentioned, bradycardia and asystole are usually the result of inadequate ventilation and hypoxemia. However, if bradycardia is refractory to adequate ventilations and chest compressions, then vasopressors and fluids may be required as per below.
- Epinephrine should be administered at a dose of 01 – 0.03 mg/kg (0.1 – 0.3 mL/kg of 1:10,000) via IV or intraosseous (IO) line. If there are delays in establishing IV or IO access it can be given via endotracheal tube at a higher dose of 0.05 – 0.1 mg/kg. The safety and efficacy of endotracheally administered epinephrine have not been evaluated, and IV or IO administration is preferred
- If blood loss is known or suspected (placental abruption, cord prolapse, cord avulsion) then crystalloid or blood should be used for volume resuscitation. The initial dose is 10 mL/kg. Overly rapid administration should be avoided, especially in premature infants, where rapid fluid shifts may lead to intracranial bleeding.
- Current recommendations advise against administration of naloxone or sodium bicarbonate in the delivery room.
- Atropine is not recommended – bradycardia is due to hypoxia and provides a valuable feedback to guide adequacy of ventilation and oxygenation. This reflex should not be pharmacologically extinguished.
Obtaining neonatal vascular access can be challenging. Peripheral venous cannulation is generally extremely difficult and can be time-consuming. The preferred options for emergent access are IO and umbilical venous cannulation.
IO access can be challenging due to the narrow marrow cavity space. IO placements, particularly with the traditional manual needles, can be unstable due to the relatively small amount of needle embedded in the bone and long lever-arm of the needle housing. The EZ-IO needles are more secure as the hub is much shorter, but the electric drill can be challenging to control. Manual insertion of the EZ-IO needles is possible, and can be considered. The needle should be angled away from the growth plate. Thus, the needle should be aimed caudally if inserting into the proximal tibia, or cephalad if inserting into the distal femur.
Umbilical venous cannulation is probably the best option for emergent IV access. To perform the procedure, start by tying a piece of suture or umbilical tape at the base of the cord. Incise the umbilical stump about 2cm from the abdominal wall. Locate the umbilical vein – it will be the largest of the lumens. Gently insert an umbilical venous catheter, or if this is unavailable a pediatric feeding tube can be used instead. Once blood is aspirated, continue to advance 1-2 cm further. Secure the catheter by tying the suture or tape that was placed at the base of the umbilicus. The umbilical line can be used for emergent medication administration, but like all central lines placed during resuscitation, it should be changed under sterile conditions as soon as possible after the patient is stabilized.
In the infant who is refractory to initial resuscitation or who rapidly decompensates, other clinical scenarios should be considered:
- Pneumothorax –may even be spontaneous in premature infants with insufficient surfactant but may also be caused by PPV or chest compressions. In addition to the usual findings of decreased breath sounds and asymmetric chest expansion, increased transillumination of the hemithorax may be a potentially helpful sign. Initial management includes a trial of aspiration using a butterfly needle inserted in the midclavicular line in the 3rd or 4th intercostal space and a large volume syringe connected to a 3-way stop cock.
- Diaphragmatic hernia – congenital diaphragmatic defects allow accumulation of abdominal organs in the thoracic cavity. These usually occur on the left and carry an extremely high mortality rate of about 33%. Clinical signs include asymmetric chest excursion, decreased breath sounds, and scaphoid abdomen. They are readily diagnosed on chest x-ray. The compression of the lungs caused by the mass of intrathoracic abdominal contents can lead to immediate respiratory compromise. This can worsen if the abdominal organs become distended due to positive pressure ventilation. If a diaphragmatic hernia is recognized, the infant should be immediately intubated and an orogastric tube placed to decompress the GI tract. Immediate pediatric surgery consultation should be sought.
References / Further Reading
 Aronson PL and Allesandrini EA: Neonatal Resuscitation, in Fleischer GR and Ludwig S, et al (eds): Textbook of Pediatric Emergency Medicine, ed 6; Philadelphia Lippincott Williams & Wilkins, 2010 (Ch 2): pp 32-45
 Vain, Nestor E., et al. “Oropharyngeal and nasopharyngeal suctioning of meconium-stained neonates before delivery of their shoulders: multicentre, randomised controlled trial.” The Lancet 364.9434 (2004): 597-602
 Wiswell, Thomas E., et al. “Delivery room management of the apparently vigorous meconium-stained neonate: results of the multicenter, international collaborative trial.” Pediatrics 105.1 (2000): 1-7.
 O’Donnell, Colm PF, et al. “Feasibility of and delay in obtaining pulse oximetry during neonatal resuscitation.” The Journal of pediatrics 147.5 (2005): 698-699.
 Davis, Peter G., et al. “Resuscitation of newborn infants with 100% oxygen or air: a systematic review and meta-analysis.” The Lancet 364.9442 (2004): 1329-1333.
 Kattwinkel, John, et al. “Part 15: neonatal resuscitation 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care.” Circulation 122.18 suppl 3 (2010): S909-S919.
 http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5602a1.htm – accessed 5/1/2015