The past several decades have witnessed a significant reduction in neonatal mortality and morbidity in the industrialized world. A variety of societal changes, improvements in obstetric care, and advances in neonatal medical and surgical care are largely responsible for these dramatic improvements. Many of the advances, in particular those related to respiratory support and monitoring devices, nutrition, pharmacologic agents, and surgical management of congenital anomalies and the airway, which have contributed to improved neonatal outcomes, are discussed in this book.
The results of these advances have made death from respiratory failure relatively infrequent in the neonatal period unless there are significant underlying pathologies such as birth at the margins of viability, sepsis, necrotizing enterocolitis, intraventricular hemorrhage, or pulmonary hypoplasia. However, the consequences of respiratory support continue to be major issues in neonatal intensive care. Morbidities such as chronic lung disease (CLD), also known as bronchopulmonary dysplasia (BPD), oxygen toxicity, and ventilator-induced lung injury (VILI), continue to plague a significant number of babies, particularly those with birth weight less than 1500 g.
The focus today is not only to provide respiratory support, which will improve survival, but also to minimize the complications of these treatments. Quality improvement programs to reduce the unacceptably high rate of CLD are an important part of translating the improvements in our technology to the bedside. However, many key issues in neonatal respiratory support still need to be answered. These include the optimal ventilator strategy for those babies requiring respiratory support; the role of noninvasive ventilation; the best use of pharmacologic adjuncts such as surfactants, inhaled nitric oxide, xanthines, and others; the management of the ductus arteriosus; and many other controversial questions. The potential benefits and risks of many of these therapeutic dilemmas are discussed in subsequent chapters and it is hoped will assist clinicians in their bedside management of newborns requiring respiratory support.
The purpose of this chapter is to provide a brief history of neonatal assisted ventilation with special emphasis on the evolution of the methods devised to support the neonate with respiratory insufficiency. We hope that this introductory chapter will provide the reader with a perspective of how this field has evolved over the past several thousand years.
History of Neonatal Ventilation: Earliest Reports
Respiratory failure was recognized as a cause of death in newborns in ancient times. Hwang Ti (2698-2599 BC), the Chinese philosopher and emperor, noted that this occurred more frequently in children born prematurely. Moreover, the medical literature of the past several thousand years contains many references to early attempts to resuscitate infants at birth.
The Old Testament contains the first written reference to providing assisted ventilation to a child (Kings 4:32-35). “And when Elisha was come into the house, behold the child was dead, and laid upon his bed…. He went up, and lay upon the child and put his mouth upon his mouth, and his eyes upon his eyes, and his hands upon his hands: and he stretched himself upon the child; and the flesh of the child waxed warm … and the child opened his eyes.” This passage, describing the first reference to mouth-to-mouth resuscitation, suggests that we have been fascinated with resuscitation for millennia.
The Ebers Papyrus from sixteenth century BC Egypt reported increased mortality in premature infants and the observation that a crying newborn at birth is one who will probably survive but that one with expiratory grunting will die.
Descriptions of artificial breathing for newly born infants and inserting a reed in the trachea of a newborn lamb can be found in the Jewish Talmud (200 BC to 400 AD). Hippocrates (c. 400 BC) was the first investigator to record his experience with intubation of the human trachea to support pulmonary ventilation. Soranus of Ephesus (98-138 AD) described signs to evaluate the vigor of the newborn (which were possibly a precursor to the Apgar score) and criticized the immersion of the newborn in cold water as a technique for resuscitation.
Galen, who lived between 129 and 199 AD, used a bellows to inflate the lungs of dead animals via the trachea and reported that air movement caused chest “arises.” The significance of Galen’s findings was not appreciated for many centuries thereafter.
Around 1000 AD, the Muslim philosopher and physician Avicenna (980-1037 AD) described the intubation of the trachea with “a cannula of gold or silver.” Maimonides (1135-1204 AD), the famous Jewish rabbi and physician, wrote about how to detect respiratory arrest in the newborn infant and proposed a method of manual resuscitation. In 1472 AD, Paulus Bagellardus published the first book on childhood diseases and described mouth-to-mouth resuscitation of newborns.
During the Middle Ages, the care of the neonate rested largely with illiterate midwives and barber surgeons, delaying the next significant advances in respiratory care until 1513, when Eucharius Rosslin’s book first outlined standards for treating the newborn infant. Contemporaneous with this publication was the report by Paracelsus (1493-1541), who described using a bellows inserted into the nostrils of drowning victims to attempt lung inflation and using an oral tube in treating an infant requiring resuscitation.
Sixteenth and Seventeenth Centuries
In the sixteenth and seventeenth centuries, advances in resuscitation and artificial ventilation proceeded sporadically with various publications of anecdotal short-term successes, especially in animals. Andreas Vesalius (1514-1564 AD), the famous Belgian anatomist, performed a tracheostomy, intubation, and ventilation on a pregnant sow. Perhaps the first documented trial of “long-term” ventilation was performed by the English scientist Robert Hooke, who kept a dog alive for over an hour using a fireside bellows attached to the trachea.
The scientific renaissance in the sixteenth and seventeenth centuries rekindled interest in the physiology of respiration and in techniques for tracheostomy and intubation. By 1667, simple forms of continuous and regular ventilation had been developed. A better understanding of the basic physiology of pulmonary ventilation emerged with the use of these new devices.
Various descriptions of neonatal resuscitation during this period can be found in the medical literature. Unfortunately, these reports were anecdotal and not always appropriate by today’s standards. Many of the reports came from midwives who described various interventions to revive the depressed neonate such as giving a small spoonful of wine into the infant’s mouth in an attempt to stimulate respirations as well as some more detailed descriptions of mouth-to-mouth resuscitation.
In the early 1800s interest in resuscitation and mechanical ventilation of the newborn infant flourished. In 1800, the first report describing nasotracheal intubation as an adjunct to mechanical ventilation was published by Fine in Geneva. At about the same time, the principles for mechanical ventilation of adults were established; the rhythmic support of breathing was accomplished with mechanical devices, and on occasion, ventilatory support was carried out with tubes passed into the trachea.
In 1806, Vide Chaussier, professor of obstetrics in the French Academy of Science, described his experiments with the intubation and mouth-to-mouth resuscitation of asphyxiated and stillborn infants. The work of his successors led to the development in 1879 of the Aerophore Pulmonaire ( Fig. 1-1 ), the first device specifically designed for the resuscitation and short-term ventilation of newborn infants. This device was a simple rubber bulb connected to a tube. The tube was inserted into the upper portion of the infant’s airway, and the bulb was alternately compressed and released to produce inspiration and passive expiration. Subsequent investigators refined these early attempts by designing devices that were used to ventilate laboratory animals.
Charles-Michel Billard (1800-1832) wrote one of the finest early medical texts dealing with clinical–pathologic correlations of pulmonary disease in newborn infants. His book, Traite des maladies des enfans nouveau-nes et a la mamelle , was published in 1828.
Billard’s concern for the fetus and intrauterine injury is evident, as he writes: “During intrauterine life man often suffers many affectations, the fatal consequences of which are brought with him into the world … children may be born healthy, sick, convalescent, or entirely recovered from former diseases.”
His understanding of the difficulty newborns may have in establishing normal respiration at delivery is well illustrated in the following passage: “… the air sometimes passes freely into the lungs at the period of birth, but the sanguineous congestion which occurs immediately expels it or hinders it from penetrating in sufficient quantity to effect a complete establishment of life. There exists, as is well known, between the circulation and respiration, an intimate and reciprocal relation, which is evident during life, but more particularly so at the time of birth …. The symptoms of pulmonary engorgement in an infant are, in general, very obscure, and consequently difficult of observation; yet we may point out the following: the respiration is labored; the thoracic parietals are not perfectly develop(ed); the face is purple; the general color indicates a sanguineous plethora in all the organs; the cries are obscure, painful and short; percussion yields a dull sound.” It seems remarkable that these astute observations were made almost 200 years ago.
The advances made in the understanding of pulmonary physiology of the newborn and the devices designed to support a newborn’s respiration undoubtedly were stimulated by the interest shown in general newborn care that emerged in the latter part of the nineteenth century and continued into the first part of the twentieth century. The reader is directed to multiple references that document the advances made in newborn care in France by Dr. Étienne Tarnier and his colleague Pierre Budin. Budin may well be regarded as the “father of neonatology” because of his contributions to newborn care, including publishing survival data and establishing follow-up programs for high-risk newborn patients.
In Edinburg, Scotland, Dr. John William Ballantyne, an obstetrician working in the latter part of the nineteenth and early twentieth centuries, emphasized the importance of prenatal care and recognized that syphilis, malaria, typhoid, tuberculosis, and maternal ingestion of toxins such as alcohol and opiates were detrimental to the development of the fetus.
O’Dwyer in 1887 reported the first use of long-term positive-pressure ventilation in a series of 50 children with croup. Shortly thereafter, Egon Braun and Alexander Graham Bell independently developed intermittent body-enclosing devices for the negative-pressure/positive-pressure resuscitation of newborns ( Fig. 1-2 ). One might consider these seminal reports as the stimulus for the proliferation of work that followed and the growing interest in mechanically ventilating newborn infants with respiratory failure.
A variety of events occurred in the early twentieth century in the United States, including most notably the improvement of public health measures, the emergence of obstetrics as a full-fledged surgical specialty, and the assumption of care for all children by pediatricians. In 1914, the use of continuous positive airway pressure for neonatal resuscitation was described by Von Reuss. Henderson advocated positive-pressure ventilation via a mask with a T-piece in 1928. In the same year, Flagg recommended the use of an endotracheal tube with positive-pressure ventilation for neonatal resuscitation. The equipment he described was remarkably similar to that in use today.
Modern neonatology was born with the recognition that premature infants required particular attention with regard to temperature control, administration of fluids and nutrition, and protection from infection. In the 1930s and 1940s premature infants were given new stature, and it was acknowledged that of all of the causes of infant mortality, prematurity was the most common contributor.
The years following World War II were marked by soaring birth rates, the proliferation of labor and delivery services in hospitals, the introduction of antibiotics, positive-pressure resuscitators, miniaturization of laboratory determinations, X-ray capability, and microtechnology that made intravenous therapy available for neonatal patients. These advances and a host of other discoveries heralded the modern era of neonatal medicine and set the groundwork for producing better methods of ventilating neonates with respiratory failure.
Improvements in intermittent negative-pressure and positive-pressure ventilation devices in the early twentieth century led to the development of a variety of techniques and machines for supporting ventilation in infants. In 1929, Drinker and Shaw reported the development of a technique for producing constant thoracic traction to produce an increase in end-expiratory lung volume. In the early 1950s, Bloxsom reported the use of a positive-pressure air lock for resuscitation of infants with respiratory distress in the delivery room. This device was similar to an iron lung; it alternately created positive and negative pressure of 1 to 3 psi at 1-min intervals in a tightly sealed cylindrical steel chamber that was infused with warmed humidified 60% oxygen. Clear plastic versions of the air lock quickly became commercially available in the United States in the early 1950s ( Fig. 1-3 ). However, a study by Apgar and Kreiselman in 1953 on apneic dogs and another study by Townsend involving 150 premature infants demonstrated that the device could not adequately support the apneic newborn. The linkage of high oxygen administration to retinopathy of prematurity and a randomized controlled trial of the air lock versus care in an Isolette ® incubator at Johns Hopkins University revealed no advantage to either study group and heralded the hasty decline in the use of the Bloxsom device.
In the late 1950s, body-tilting devices were designed that shifted the abdominal contents to create more effective movement of the diaphragm. Phrenic nerve stimulation and the use of intragastric oxygen also were reported in the literature but had little clinical success. In the 1950s and early 1960s, many centers also used bag and tightly fitting face mask ventilation to support infants for relatively long periods of time.
The initial aspect of ventilator support for the neonate in respiratory failure was effective resuscitation. Varying techniques in the United States were published from the 1950s to the 1980s, but the first consensus approach was created by Bloom and Cropley in 1987 and adopted by the American Academy of Pediatrics as a standardized teaching program. A synopsis of the major events in the development of neonatal resuscitation is shown as a time line in Box 1-1 .
1300 BC: Hebrew midwives use mouth-to-mouth breathing to resuscitate newborns.
460-380 BC: Hippocrates describes intubation of trachea of humans to support respiration.
200 BC-500 AD: Hebrew text (Talmud) states, “we may hold the young so that it should not fall on the ground, blow into its nostrils and put the teat into its mouth that it should suck.”
98-138 AD: Greek physician Soranus describes evaluating neonates with system similar to present-day Apgar scoring, evaluating muscle tone, reflex or irritability, and respiratory effort. He believed that asphyxiated or premature infants and those with multiple congenital anomalies were “not worth saving.”
1135-1204: Maimonides describes how to detect respiratory arrest in newborns and describes a method of manual resuscitation.
1667: Robert Hooke presents to the Royal Society of London his experience using fireside bellows attached to the trachea of dogs to provide continuous ventilation.
1774: Joseph Priestley produces oxygen but fails to recognize that it is related to respiration. Royal Humane Society advocates mouth-to-mouth resuscitation for stillborn infants.
1783-1788: Lavoisier terms oxygen “vital air” and shows that respiration is an oxidative process that produces water and carbon dioxide.
1806: Vide Chaussier describes intubation and mouth-to-mouth resuscitation of asphyxiated newborns.
1834: James Blundell describes neonatal intubation.
1874: Open chest cardiac massage reported in an adult.
1879: Report on the Aerophore Pulmonaire, a rubber bulb connected to a tube that is inserted into a neonate’s airway and then compressed and released to provide inspiration and passive expiration.
1889: Alexander Graham Bell designs and builds body-type respirator for newborns.
Late 1880s: Bonair administers oxygen to premature “blue baby.”
1949: Dr. Julius Hess and Evelyn C. Lundeen, RN, publish The Premature Infant and Nursing Care , which ushers in the modern era of neonatal medicine.
1953: Virginia Apgar reports on the system of neonatal assessment that bears her name.
1961: Dr. Jim Sutherland tests negative-pressure infant ventilator.
1971: Dr. George Gregory and colleagues publish results with continuous positive airway pressure in treating newborns with respiratory distress syndrome.
1987: American Academy of Pediatrics publishes the Neonatal Resuscitation Program based on an education program developed by Bloom and Cropley to teach a uniform method of neonatal resuscitation throughout the United States.
1999: The International Liaison Committee on Resuscitation (ILCOR) publishes the first neonatal advisory statement on resuscitation drawn from an evidence-based consensus of the available science. The ILCOR publishes an updated Consensus on Science and Treatment Recommendations for neonatal resuscitation every 5 years thereafter.