Transport of the Ventilated Infant




Acknowledgment


We would like to acknowledge Dr. Kristen Melton and Dr. Gary Pettett for their contributions in the earlier edition of this chapter.




Important Role of the Transport Team


The widespread development of both regional perinatal centers and interhospital transport services for critically ill newborns and infants has been an important factor in decreasing perinatal morbidity and mortality. Starting in the 1970s, the growing recognition that regionalization of care improved patient outcomes resulted in the formation of regionalized centers for perinatal and neonatal care. With this development of regionalized care, the need for skilled transport teams was realized. Today, as advanced technologies have become more available and portable, the transport team has become an extension of the intensive care unit, and transport teams now initiate the comprehensive specialized care in the referral hospital that will be continued in the tertiary care center. Transport teams bring the intensive care environment to the infant, even starting care in the referring hospital’s delivery room, stabilizing the infant to ensure a safe and effective transfer.


As advanced technologies have been approved and adopted, sophisticated treatments such as high-frequency ventilation (HFV) and inhaled nitric oxide (iNO) are now frequently initiated in many level III units. When these therapies fail to stabilize the infant in intensive care units that do not offer extracorporeal membrane oxygenation (ECMO), transport to a quaternary neonatal care unit is often necessary. Transfer of these highly complex neonates requires a sophisticated and skilled transport team and may be aided by real-time audio and video cell phone capabilities and wireless electronic medical records.


The modern transport team has adapted to meet the needs of these complex infants. Teams now have the ability to provide intensive therapies such as surfactant therapy, HFV, iNO, passive or active therapeutic hypothermia, and even mobile ECMO in some cases. Team members competent in the critical care of an ill newborn must be able to provide a rapid response to the referral hospitals who request their services. They must provide appropriate stabilization for transport in an expedient and safe manner. Importantly, as the skills and technologies of transport teams continue to change and develop, it is becoming evident that comprehensive care and therapies initiated during transport can improve patient outcomes.




Regionalized Care


In the early 1970s, clinicians recognized that neonates treated at tertiary centers had improved outcomes, and the push for regionalized care began. Usher demonstrated a 50% reduction in mortality for critically ill newborns who received care at tertiary centers. Other studies confirmed these results and also showed improved mortality rates for infants transported to regional care centers.


Although the previous studies supported the early transfer of high-risk mothers and fetuses to tertiary centers, the birth of high-risk infants in nontertiary centers has continued to occur, and data suggest that 14% to 30% of very low birth-weight (VLBW) infants are delivered in nontertiary hospitals. Studies of such infants further support the fact that outborn infants experience significantly higher morbidity and mortality compared to infants delivered at tertiary perinatal centers. Chien et al. found that outborn infants were at higher risk of death, severe intraventricular hemorrhage (IVH), patent ductus arteriosus, respiratory distress syndrome (RDS), and nosocomial infections, even after adjusting for perinatal risks and illness severity.


Lui et al. performed an interesting study comparing inborn and outborn infants born between 23 weeks and 28 weeks 6 days of gestation before and after the development of regionalized care. They compared outcomes for infants born from 1992 to 1995 to those born from 1997 to 2002. They showed that optimization of in utero transfers resulted in 25% fewer nontertiary hospital births and that with provision of perinatal consults, increased provision of antenatal steroids, and centralization of the neonatal retrieval system, outborn mortality rates decreased significantly from 39.4% to 25.1%. Rates of severe IVH and necrotizing enterocolitis (NEC) also decreased in outborn infants between the two periods after interventions were started. Importantly, however, morbidity for outborn infants continued to be significantly higher than that for inborn infants, especially with regard to severe (grade 3 or 4) IVH (19.4% outborn vs 10% inborn, p = 0.002) and radiologically or surgically proven NEC (7.2% outborn vs 1.7% inborn, p < 0.001). These data demonstrate that implementation of a coordinated system to provide perinatal consults and appropriate neonatal transport improves outcomes, but outborn infants continue to face higher morbidity despite these interventions. Thus in utero transfer of high-risk pregnancies to a tertiary center remains the best option. When maternal transfer cannot be accomplished because of rapid labor progression, pending delivery, or fetal or maternal compromise, the specialized services offered by the neonatal transport team play an important role in optimizing outborn infant care. Many teams will even now offer to attend unexpected high-risk deliveries in community settings if a maternal transport is prohibited.




Transport Team Composition


Multiple approaches have been used when determining the makeup of the ideal transport team. Each institution must determine the most appropriate model for their facility based on the volume, types of transport (ground vs rotor wing vs fixed wing), travel times, skills required for efficient and safe transfers, availability of team members, and overall costs. The American Academy of Pediatrics (AAP) has recommended that transport teams consist of at least two providers, with one member being a nurse who has 5 years or more of nursing experience. Team members can include emergency or intensive care nurses, nurse practitioners (NPs), pediatric respiratory therapists (RTs), paramedics, and physicians, including attending staff, fellows, or residents in training. Most commonly teams are made up of RT/nurse pairs or nurse/nurse pairs with paramedic support. Given the significant number of neonatal transports requiring respiratory interventions, many teams find the skills of an RT helpful and often necessary. However, all transport team members should be cross-trained and capable of supporting all transport procedures and interventions.


Karlsen et al. have studied transport volume and various team models and their effects on patient care outcomes. Karlsen’s survey found wide variation in many aspects of team organization, including team configuration, staff orientation, and use of protocols as well as quality improvement methodologies. Consistent with previous work, Karlsen found no difference in patient care outcomes when comparing variations in team members, including RN/RT, NP/RT, and MD/RN/RT. The presence of a physician did not alter patient outcomes in this study.


Multiple other studies have supported the idea that nonphysician teams are capable of providing care that is effective, and potentially timelier, than teams accompanied by a physician. Beyer et al. demonstrated that nonphysician teams were able to provide care and transport intubated neonates without problems. In their cohort, 20% of infants were intubated by a transport nurse or RT at the referring facility. They concluded that there was a low incidence of complications in intubated neonates when transported by personnel trained in intubation and neonatal resuscitation. Leslie and Stephenson found that transports directed by advanced neonatal NPs were as effective as those directed by physicians, and King et al. found that there was no change in mortality or complications when teams were converted from nurse/physician teams to nurse/nurse teams but that response time did improve. Voluntary reporting by pediatric and neonatal transport teams to the AAP Section of Transport Medicine team database indicates that almost half of the teams providing information (37 of 82 teams) do not include physicians on transport. Thus with a well-trained, experienced transport team, availability of a medical control physician by telephone may be all that is required.


Regardless of the model chosen, however, team members should be specialists in neonatal and pediatric care because specialized teams have been shown to make a significant difference in outcome. Early studies demonstrated that dedicated neonatal transport teams reduced both morbidity and mortality in VLBW infants who required transfer to a tertiary center and that outborn infants who were not transferred by a specialized transport team experienced a 60% greater mortality rate.


More recent studies confirm that the incidence of transport-related morbidity increases when personnel without specific pediatric training transport critically ill children. A study by Edge et al. demonstrated that adverse events during interhospital transport, such as accidental extubation or intravenous (IV) access problems, were significantly higher in transports performed by a nonspecialized team (20%) compared to transports performed by a specialized pediatric team (2%). Similarly, Macnab demonstrated a higher rate of secondary complications in infants transported by nonspecialized transport teams compared to pediatric transport teams.


High-volume transport programs have the advantage of being able to develop full-time transport teams dedicated solely to neonatal transport, in which experience is greater and skills are more easily maintained. Smaller services that use team members on a more infrequent basis must invest significantly in continuing education to maintain their knowledge base and technical skills to provide specialized services. Data from the ongoing AAP voluntary registration of transport teams suggest that the majority of teams provide combined pediatric and neonatal transport services. Although this is often necessary and allows the maintenance of a dedicated team, team members should track the number of neonatal transports they perform to be sure they are maintaining adequate exposure to the unique circumstances involved in neonatal resuscitation and transport. A lack of exposure should be offset by continuing education including in-unit training and simulation.


Transport teams are frequently called to attend and participate in the deliveries of high-risk preterm infants that occur outside of the tertiary center. Although all delivery hospitals should have at least one attendant certified in neonatal resuscitation available at all times, transport personnel may be asked to support referral staff or, in some cases, may be the primary resuscitator at a preterm delivery. Although this is often a stressful situation, data demonstrate that the presence of a dedicated neonatal retrieval team can improve delivery room resuscitation of these outborn premature infants. In this study, neonates who were resuscitated by a specialized transport team were intubated more promptly with fewer attempts, had fewer accidental extubations, and were more likely to receive surfactant therapy in a timely manner.


Neonates cared for only by the referring hospital team had higher rates of hypothermia, lack of vascular access, and more extensive resuscitation. Despite having the same average gestational age, infants resuscitated by the referral team received longer chest compressions (6 min vs 0.5 min), longer bag–mask ventilation (13.5 min vs 7 min), and longer continuous positive airway pressure (CPAP) (14 min vs 2 min), all of which may reflect a delay in intubation by the referral team. These differences are not surprising, because referral hospitals that appropriately transfer high-risk mothers and fetuses lack a critical mass of preterm births and experience in resuscitation of extremely low birth-weight (ELBW) and VLBW preterm infants.


Dedicated teams with specialized training and increased experience are able to provide better specialized care and resuscitation. Given the evidence that the first few minutes of resuscitation and early oxygen exposure can influence long-term outcome, the need to optimize resuscitation is evident. These studies reinforce the fact that transport teams should be made up of clinicians with specific training in comprehensive neonatal care and resuscitation and also suggest that the use of the transport team as a neonatal resuscitation team for outborn infants may be optimal.




Transport Education


The need for extensive education of team members who transport neonates is obvious, because team members are expected to recognize and treat a wide array of disorders. They must be able to resuscitate and stabilize neonates in critical condition and ensure their safe transport, often under conditions that may be suboptimal. Although no standard curriculum exists, guidelines for team education have been published by the AAP Section on Transport Medicine. Education of transport team members includes a requirement for resuscitation training through the Neonatal Resuscitation Program (AAP and American Heart Association provider course) or a similar program, as well as continuing education in neonatal pathology and disease. Continuing medical education (CME) and transport review conferences ensure that team members maintain their skills in neonatal stabilization and expose them to new topics in neonatal care. CME opportunities should include skills lab, with stations focusing on skilled intubation, effective bag–mask ventilation, handling of the difficult airway, chest tube placement, and vascular access, including IV line placement, umbilical line placement, and intraosseous line placement. In addition, simulation-based exercises should be employed when possible.


Unique to transport team education are the requirements for basic knowledge about flight physiology and its contribution to disease states, the physical and mental stresses of transport, and the need for a significant focus on safety that includes both team and patient safety. Given the many unique challenges encountered during transport (excessive noise, vibration and rotation forces, low-level lighting, variable ambient temperatures/humidity, and the need for specific safety measures), team members should receive extensive supervised orientation and then must participate in transports with sufficient regularity to maintain their skills in all transport settings. Team members may also benefit from training on ethical and legal issues such as the withdrawal of support, because they may be involved in situations in which support is stopped after resuscitation or in which infants are deemed appropriate for withdrawal of care at the referring facility, in which the family can participate, rather than for transport to a distant facility. Training should also be given regarding the social aspects of transport to help team members work more compassionately with families and help raise team awareness of the many emotional issues that are faced by parents and family members during the crisis precipitated by a neonatal transport.




Transport Physiology


The effects of altitude and the stresses of flight can have a significant impact on the neonate during fixed-wing or helicopter transport, especially in the already compromised infant. The transport environment itself, including ground transport, introduces unique stressors such as noise, vibration, and temperature variation. Transport team members must understand altitude physiology and the physiologic stresses of neonatal transport to anticipate and properly treat problems that may occur during transport. Each of these factors can affect team members as well. The most significant concerns include the following:



  • 1.

    Hypoxia


  • 2.

    Air expansion


  • 3.

    Noise and vibration


  • 4.

    Thermoregulation



Hypoxia


As an aircraft ascends, the partial pressure of gas decreases. As the altitude above sea level increases, the barometric pressure falls, and the partial pressure of ambient oxygen and thus the alveolar oxygen partial pressure decrease. During this time, infants may develop hypoxia. This is demonstrated using the simplified alveolar gas equation, P ao 2 = (P B − 47) × FiO 2 − PaCO 2 /0.8, where P ao 2 is the partial pressure of alveolar oxygen, P B is the barometric pressure, 47 is the partial pressure of water vapor, FiO 2 is the inspired oxygen concentration, PaCO 2 is the partial pressure of arterial CO 2 , and 0.8 is the respiratory quotient. If an infant receiving 50% inspired oxygen with a PaCO 2 of 50 is transported from sea level (barometric pressure = 760) in a nonpressurized plane that must achieve 8000 feet for the transfer (barometric pressure = 570), then the alveolar oxygen partial pressure will drop from 294 at sea level to 199 at altitude, if you assume no change in minute ventilation, FiO 2 , or PaCO 2 . In reality, the partial pressure of arterial CO 2 will decrease at altitude as well, making the alveolar oxygen partial pressure slightly greater than that calculated by the following equation:


<SPAN role=presentation tabIndex=0 id=MathJax-Element-1-Frame class=MathJax style="POSITION: relative" data-mathml='PAO2(sealevel)=(760−47)×0.5−50/0.8=294′>PAO2(sealevel)=(76047)×0.550/0.8=294PAO2(sealevel)=(760−47)×0.5−50/0.8=294
P AO 2 ( sea level ) = ( 760 − 47 ) × 0.5 − 50 / 0.8 = 294

<SPAN role=presentation tabIndex=0 id=MathJax-Element-2-Frame class=MathJax style="POSITION: relative" data-mathml='PAO2(8000ft)=(570−47)×0.5−50/0.8=199′>PAO2(8000ft)=(57047)×0.550/0.8=199PAO2(8000ft)=(570−47)×0.5−50/0.8=199
P AO 2 ( 8000 ft ) = ( 570 − 47 ) × 0.5 − 50 / 0.8 = 199


Preterm infants, infants with respiratory diseases, and infants with high oxygen demands (sepsis, shock) are at particular risk of developing hypoxia. Careful monitoring of oxygen saturation helps with identification of infants experiencing hypoxia, who usually respond to increased FiO 2 levels or increased positive end-expiratory pressure (PEEP). For infants already receiving oxygen prior to transport, the need for increased oxygen during flight should be anticipated. The anticipated adjustment in oxygen administration can be calculated using the following equation:


<SPAN role=presentation tabIndex=0 id=MathJax-Element-3-Frame class=MathJax style="POSITION: relative" data-mathml='AdjustedFiO2=(FiO2×PB1)/PB2′>AdjustedFiO2=(FiO2×PB1)/PB2AdjustedFiO2=(FiO2×PB1)/PB2
Adjusted Fi O 2 = ( Fi O 2 × P B 1 ) / P B 2

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Jan 30, 2019 | Posted by in PEDIATRICS | Comments Off on Transport of the Ventilated Infant

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