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Pediatric Anesthesia

Anesth Analg 57.634-646, 1978

Pediatric Anesthesia in Perspective Sixteenth Annual Baxter-Travenol Lecture ROBERT M. SMITH,

MD*

P

teria relating to both clinical and nonclinical aspects. Extending the capability of the surgeon seems the reasonable measure of progress in It is time to look back, around, and ahead, clinical anesthesia. This would include ento check the course that we have been fol- abling the surgeon to perform more extenlowing, and the direction in which we seem sive and more difficult procedures on sicker (and smaller) patients, at the same time to be heading. reducing mortality and morbidity. Widening What I hope to do is to present a broad the sphere of surgical operations should ocview of the field of pediatric anesthesia as cur with increasing availability of skilled it now stands, evaluate some of its accom- pediatric anesthesiologists, allowing surgeons plishments, sort out some of its weaknesses, greater opportunity to operate in ambulalook at portents of the future, and attempt tory surgical areas and in less specialized to suggest paths that might be taken for hospitals. further improvement of the services that this Both the care of awake patients and the subspecialty might be able to supply. reduction of suffering and emotional stress There are many who will disagree with are definite measures of progress in our field. my opinions, especially among my younger Nonclinical criteria of progress in pediassociates, whose views I greatly respect. Nothing would please me more than to have atric anesthesia should include the promopresent figures bettered, and to have my tion of teaching and constructive investigapremonitions and warnings prove unwar- tion. Let us examine these developments more closely. ranted. It is definitely in the clinical field that peMost observers would agree that on the diatric anesthesia has made its greatest prosurface of things, pediatric anesthesia has been progressing at an acceptable rate. In gress, and this primarily by extending the evaluating this progress, it is important to capability of the surgeon. A backward glance differentiate what is truly an improvement will help evaluate progress in this area. from something that is simply “new.” There Looking ’way back to 1912, one surgeon has been an inordinate emphasis on “what stated that any operation on a child that is new” in many fields of anesthesiology, lasted more than 15 minutes was doomed to often with little relation to the actual value failure. Looking back to 1940 or 1950, where we place the beginning of pediatric anestheof the particular items being introduced. sia as a special field of endeavor, tentative I believe that progress in pediatric anes- beginnings had been made in pediatric surthesia should be measured by definite cri- gery. The patent ductus arteriosus had been

anesthesia has been in existence as a subspecialty for slightly over 30 years, dating back to the end of World War 11. EDIATRIC

*Clinical Professor of Anesthesia, Harvard Medical School; Director of Anesthesia, Children’s Hospital Medical Center, Boston, Massachusetts Presented at the 52nd Congress of the International Anesthesia Research Society, San Francisco, March 21, 1978. Accepted for publication: July 28, 1978

Anesth Analg 57634-646, 1978

Robert M. Smith

closed in healthy children of school age, and infants with tracheo-esophageal fistulae were the greatest challenge of that day, but only in major pediatric centers. In the outlying areas tonsillectomy, appendectomy, and fracture reduction made up the bulk of the surgery on children. Improvements in the intervening years, definitely coming from a multitude of sources, now enable surgeons to operate for an hour or more inside the bloodless, still heart of a premature infant, to transplant kidneys in children with advanced renal failure, and to undertake 15-hour midface advancement procedures on children, while ductus arteriosus, tracheo-esophageal fistula, and ureteral reflux operations are being performed in suburban hospitals. The incidence of anesthetic mortality should be an essential measure of anesthetic excellence. Due to the difficulty in determining the true cause of operative death, reliable statistics have been hard to produce. Earlier estimates, based on the study of Beecher and Todd,l and others, placed the incidence of anesthetic death in adults a t 111500, while the incidence of anesthetic death in children under 10 years old was generally believed to be considerably higher, and children within this age group were widely considered to represent increased anesthetic risk (table 1 ) . For many years, this concept was used as an excuse for complications and deaths that should have been avoided. While it is still difficult to obtain accurate statistics and definite causes of death, it has been possible to produce enough evidence to correct the idea that pediatric patients present increased risk.

635

children between 1 and 10 years of age should have higher expectation of surviving anesthesia than patients of all other ages. The second phase in correcting this concept is now under way. Mortality in infant surgery has been reduced to such an extent that operations previously postponed until children were 3 or 4 years old are being performed nearer and nearer to the neonatal stage, and many of those operations that are mandatory a t birth are now being performed with remarkable success. This I believe is a major advance. Our evidence consists of large numbers of procedures of similar type in which there have been no deaths of any kind. The record of the Pittsburgh Eye and Ear Infirmary,’ in which 37,000 children underwent tonsillectomy without a death, is an example. A t the Philadelphia Children’s Hospital 50 infants with uncomplicated tracheo-esophageal fistulae have been operated upon without any deaths.3 In such statistics there is no possibility of shifting of blame, or juggling of figures.

In surveying the total experience where deaths have occurred, an extremely thorough study must be made to produce reliable figures. Such a study has recently been reported by Elwyn’ in an inclusive series of all children who received anesthesia at the Primary Children’s Medical Center in Salt Lake City from 1970 to 1975. The record of 1 anesthetic death in 29,000 pediatric anesthetics stands as an excellent achievement. While such records cannot be regarded as standards that all should be expected to maintain, it is hoped that such figures will be used in the future in determining The concept that all children under 10 who should administer anesthesia to chilcarried increased anesthetic risk was altered dren, where surgery should be performed, first when it was shown that 90% of the and what allowances, if any, should be made operative mortality occurred during the first if unexplained operative deaths occur in 6 months of life. We know now that normal infants and children. TABLE 1 Mortality in Pediatric Anesthesia and Surgery

Previouslv Established Concepts (19.55) Adults: Incidence of anesthetic mortality

1/ 1500

Children (0-10 yrs) : Various figures, higher incidence

1/1000~

Statistics Now Available (1978) Tonsillectomy: 37,000 cases (Pittsburgh)

No deaths

Neonates: 50 uncomplicated tracheoesophageal fistulae (Philadelphia)

No deaths

All types: 29,000 procedures, 1970-1975 (Utah)

1 anesthetic death

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Pediatric Anesthesia

Anenth Analg 57:69&646. 1978

The reduction of mortality and other anesthetic complications has brought several changes. It has enabled surgeons to perform operations in other than pediatric centers (a questionable contribution), and to institute outpatient surgery on a far more extensive scale-in most cases a very definite advantage for child, parents, parking, and pocketbook.

consciousness, major factors in developing the outpatient surgery of today. The elimination of ether introduced a major change in underlying concepts. The explosive potential of ether formerly was overlooked in view of the fact that ether was the only agent that supported respiration, the quality of respiration at that time serving as the most reliable guide to anesthetic depth.

It would seem reasonable to determine what major factors contributed to the pronounced gains in pediatric anesthesia. It is impossible to name all, for there have been many, and they have been derived from many sources, both inside and outside the field itself. Contributions in technical details of pediatric anesthesia include those of equipment, agents, anesthetic technics, and supportive care, as well as improvements in surgery and contributions from other fields.

The situation now is reversed. Today any inflammable agent is considered obsolete, and stimulation of respiration is of little importance because ventilation is usually either assisted or controlled.

Among the improvements in equipment have been masks, endotracheal tubes, airways, laryngoscopes, and anesthesia machines, most of which originated in adult anesthesia. The elimination of the frightening black rubber mask, and its replacement by lightweight plastic masks and breathing tubes, have been particularly valuable, being far less objectionable to the child, and, by reason of their transparency, reducing the danger of aspiration.

Out of this change has come a still greater departure from tradition. Endless effort had been spent in studying methods of avoiding dead-space and resistance in fashioning breathing equipment, for these are the factors that lead to increased work of breathing. With general abandonment of spontaneous respiration, ventilation by passive control is assured, and the work of breathing is eliminated, or at least reduced to inconsequential proportions. Instead of concentrating on maintaining the largest possible airway, we now insist upon using equipment that avoids distention or pressure, preferring instead to maintain a slight leak around the endotracheal tube to minimize the possibility of trauma.

The improvement in anesthetic agents has been of great importance. Of those used in 194hdiethyl ether, divinyl ether, tribromoN,O ethanol, cyclopropane, and N,O-nly and local anesthesia survive. The elimination of explosive agents, particularly etherfor years the undisputed mainstay of pediatric anesthesia-and its replacement by halothane has proved to be one of the greatest advances in our field, enabling us to set aside the confusion of rational and irrational precautionary measures, but of greater importance, allowing free use of electric surgical and monitoring devices. The use of cautery has been of unexpected value, reducing blood loss, in our experience, by as much as 80% in many cases. Unfortunately, there has not been a parallel reduction in operating time, surgeons showing increasing disregard of the passage of time in the operating room. While this may reflect increased confidence in anesthesia, the situation in many teaching hospitals has reached dangerous proportions.

The replacement of ether by halothane was momentous, and of more revolutionary nature in pediatric than in adult age groups; however, it did not produce the marked resistance occasioned by the introduction of endotracheal intubation or the use of muscle relaxants in infants and children. Many surgeons took strong stands against both of these innovations, and for years these methods were looked upon with disfavor, and blamed for numerous complications. The current unquestioned acceptance of the anesthesiologist's choice of agent and technic by surgeons is a far cry from the situation of the 1940's and 1950's, when the surgeons still felt it their prerogative and responsibility to have a major voice in the management of anesthesia. The agents generally used and our technics for using them now seem to be established on fairly firm ground. There appear to be several methods of managing almost any patient, and we seldom insist that there is only one correct way to approach a given situation.

Additional advantages in the elimination of ether have been marked reduction in postoperative nausea and faster return of full

Halothane leads all other agents for use in pediatric patients, but is supported by thiopental, muscle relaxants, N20, ketamine,

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Robert M. Smith

IV narcotics, and local anesthetics, providing combinations applicable for most of the surgical procedures now undertaken. Thus, the need for better anesthetics does not appear to be immediate or urgent, even though present agents are still not perfect, and the search for the ideal agent continues. The danger of halothane hepatotoxicity, if existent at all, is believed to be less in children than in adults. This belief was strengthened by a survey of 1,500,000 patients under 21 years of age who were anesthetized with halothane. There were 15 deaths in which halothane was involved but only 5 in which halothane was the principal suspect, and only 2 of these were prepubertal.; The use of muscle relaxants is widely accepted. The several complicating actions of succinylcholine are well documented, while the nondepolarizing relaxants stand among the most reliable and predictable drugs in our practice. In spite of the numerous conflicting studies of drug tolerance and intolerance, clinical use of all muscle relaxants follows relatively standard lines, and dosages, though altered slightly by personal biases, tend to agree rather closely. Table 2 shows dosages of relaxants commonly used, to which I have added my own adaptation of the dosage of succinylcholine for intubation of small infants. Instead of giving enough to cause apnea, with the attendant risk of hypoxia, the use of a subapneic dose, approximately 1 mg/kg of succinylcholine given IM, allows continuous, adequate ventilation, but reduces the infant’s activity enough to make intubation relatively simple.

and barrels of discarded devices. To the simple T-tube one now adds expiratory limb of specific dimensions, bag, valve (optional), heating and humidifying adaptations, and scavenging device! While this appears confusing to the novice, application is not difficuIt; and we feel that technics as well as agents are reliable, practical, and adequate for the present time. There has been increasing interest in the field of monitors in all branches of anesthesia. The remarkable progress that already has taken place probably represents the mere beginning of a rapidly accelerating surge of instrumentation. In comparison to the relatively stable position of agents and technics in pediatric anesthesia, the whole situation in relation to monitors is widely varied, highly dynamic, and actively disputed. The word “monitor,” generally used to denote an instrument in our application, literally means a guardian or watcher. It is important to remember that we are endowed with several extremely valuable monitoring devices that frequently are overlooked. These are the eyes, ears, and fingers, which, acting as sensors, and filtered through the brain, as computer, provide continuous information of inestimable value (table 3). It should be emphasized that in pediatric anesthesia it is absolutely essential for the anesthesiologist to observe the operation continuously, with complete knowledge of

There has been continual change in anesthetic technics. Open-drop administration was discarded with the elimination of ether, all other agents requiring technics affording ventilatory assistance. The variety of closed and semiclosed technics, nonrebreathing valves, and the endless variations on the T-tube have resulted in volumes of papers-

TABLE 3 Monitoring Methods: Basic Monitors

Eyes Ears Fingers

Anesthesia chart

+

Stethoscope Blood pressure Temperature

TABLE 2 Pediatric Use of Muscle Relaxants -~ Agent

Succinylcholine Standard dosage subapneic dose d-Tubocurarine Metubine (1/2 dtc) Pancuronium (1/5 dtc)

Intubation

1 mg/kg IV (2 IM) 1 mg/kg IM

Supplementation

... ...

0.5 mg/kg IV

0.3 mg/kgIV

0.25 mg/kg IV

0.15 mg/kg IV

0.1 mg/kg IV

0.06 mg/kg IV

Pediatric Anesthesia

638

what the surgeon is doing, how the child is reacting, and what problems are being encountered. In the same vein, it is of utmost importance for anesthesiologist and surgeon to work together, to communicate freely, and to each be cognizant of the other’s plan of action. One of the most valuable advances in pediatric anesthesia has been the very close relationship and mutual respect between anesthesiologist and surgeon, and the elimination of the rather stupid antagonism that once was nurtured in many institutions. The major interest in monitors today is directed toward instrumental devices of increasing sophistication and of disputed indication. There are four basic monitors, however, which now are widely considered to be indicated for all pediatric anesthesia. It might be said with reason that the establishment of routine use of these monitors has been the most valuable of all advances in our field.

If used properly, the anesthesia chart serves as a basic monitor. Proper use means that documentation is started before the anesthesia is begun, and the responses to induction are measured and recorded. A thorough chart should show gradual, as well as abrupt, changes, which might not be recognizable unless visibly displayed. The value of the anesthesia chart should be considerably enhanced when automatic recording of trends in body functions becomes available in the near future. The chart is listed first, not because it is most important, but because it should come into play first, in the course of the anesthetic procedure. The first instrumental monitor to be applied in the field of pediatric anesthesia, the precordial (or esophageal) stethoscope, has become-rightfully, I believe-the mark of the pediatric anesthesiologist, without which no anesthetic shouId be undertaken regardless of the presence of more advanced elec-

Anesth Analg 57:634-646, 1978

tronic instruments. The precordial stethoscope is one of the few major advances that originated within the field of pediatric anesthesia, and was subsequently adopted for use in adult anesthesia, in contrast to most other innovations, which have been brought into our field after prior development in other areas.

For many years after the measurement of arterial blood pressure had become routine in adult anesthesia, it was regarded as of slight importance in the anesthetic management of children, and impossible in infant management. The development of accurate, noninvasive methods of arterial blood pressure determination in infants and children of all ages has been of great significance, and the alterations observed in infants have been found to be more informative than those of any other age group. Safety, simplicity, and practicality give the blood pressure cuff unchallenged position next to the stethoscope as a standard, mandatory monitor for pediatric anesthesia. The fourth monitor of standard use is the thermometer. It is less reliable, less foolproof, and less mandatory than the stethoscope and blood pressure cuff, but is now accepted as one of the essential devices. The additional monitors being used in pediatric anesthesia appear to be of more importance under special indications (table 4).

Monitors seem to cast a spell over many of us, particularly the younger members of our specialty. I am convinced that younger individuals, who have not become familiar with physical signs and have natural facility with instruments, have a tendency to turn to the instruments too quickly, and use them more often than necessary, while older individuals, who are accustomed to getting along without and have less skill with in-

TABLE 4 Monitoring Methods: Supplementary Monitors and Measurements

1. Fluids given, urine output 2 . Measured blood loss 3. Venous pH, P C O ~ 4.

Arterial Poz, Pcoz

5. Inspired 0, concentration 6. End-expired CO, 7. Anesthetic vapor concentration 8. Tssue 0,. CO,

Electrocardiograph Central venous pressure Nerve stimulator Cardiac output Right and left atrial pressures 14. Serum Na, K, Cat+,protein 15. Serial hematocrit 9 10. 11. 12. 13.

16. Coagulogram

Anesth Analg

Robert M. Smith

57:fi34-646, 1978

struments, hesitate too long to take advantage of the help that monitors can provide. How fortunate to be exactly 40 years old! Among measurements currently made, whether by instrument or other means, blood-gas determinations are among the foremost; and the availability of accurate blood-gas determinations on a 24-hour basis has become another essential in a properly equipped operating room. Measurement of blood loss, urine output, and central venous pressure follows practical indications, that of central venous pressure providing less reliable information in smaller children, and being essential only in more extensive procedures or during operations on particularly poor-risk patients. The electrocardiograph, contrary to the opinion of many, I believe is of little value in uncomplicated procedures on normal children. The cardiac irregularities seen in children seldom appear to be of significance and are more apt to upset and distract the anesthesiologist than to harm the child. I a m sorry to see the spreading tendency to drape an anxious child with paste, wire, and electrodes before starting a tonsillectomy. It has been argued that one should use all the safeguards available when anesthetizing a child, but if one considers the rapidly growing list of so-called safeguards, it is obvious that the line must be drawn somewhere (before the bottom of the list), and while there may be definite indication for the use of each, the needless use of any imposes more burden than safeguard. One does not put overshoes on a duck. Rather than describing the use of each monitor, I should like to point out a few of the disadvantages that should be considered before one reaches for the switch (table 5). Some, such as the loss of a hand or foot,

are all too obvious, but others, such as the added exposure of an infant during preoperative instrumentation, or the distraction of the anesthesiologist’s attention during operation, are less commonly appreciated. The fact that the use of many monitors is complicated and requires practice and skill means that to be prepared to use them with accuracy on sick patients, one may have to learn on patients who would not ordinarily require their use. When this involves the manipulation of invasive devices, it presents a definite problem in ethics. One of the most objectionable effects of monitoring the postoperative infant or child is seen in the absolute and prolonged immobilization that frequently is involved. It imposes a hardship for the child to endure and provides an open invitation for vascular stasis and ventilatory problems. In spite of their disadvantages, monitors are of tremendous value in measuring the condition of the patient and guiding therapy. For best development of their potentiality, it is important to know what to look for in their adaptation for pediatric use. Desired features (table 6) include the obvious bids for safety, simplicity, and easy serviceability. Features less frequently stressed are widely observable signals and alarms. Many currently popular monitors, including the stethoscope and thermometer, are designed for use of the anesthesiologist only. Too many times there has been a bout of asystole or a sudden rise in temperature that has gone unnoticed for a critical lapse of time because the single listening-post was not being manned, whereas a generally audible alarm would have demanded immediate response. We expect much more help from monitors in the future in evaluation of tissue and fluid

TABLE 5 Disadvantages and Potential Dangers of Monitoring Devices

Exposure of child Alarm, pain in establishment Delay in starting operation Injury: Nasal, urethral, rectal trauma Tracheitis, esophageal perforation Tissue injury, blood loss Vascular irritation, embolus Loss of digits, extremity, or life Burns (heat, electric)

639

Long-term immobilization of child Interruption of rest Mechanical breakdown, monitor error Distraction of anesthesiologist’s attention Practice required to develop skill needed for critically ill

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640

TABLE 6 Monitors: Desired Features and Measurements Needed ~

~

Desired features

Practical Reliable Accurate Noninvasive Signals widely observed Alarms widely observed Stable, durable Easily serviced, adjusted Simple Inexpensive metabolism and numerous aspects of cardiac, respiratory, and renal function. A particular need is the ability to evaluate consciousness and the sensation of pain. The inability to recognize these two components in paralyzed patients stands as a major deficiency in the practice of anesthesiology. Another area where major advances have been made is that of patient support. Supportive care has played an increasingly important role in the successful outcome of pediatric operations, sicker and smaller patients depending more and more upon this factor. In many situations, prevention of intercurrent infection in handling neonates and maintenance of body temperature have become of greater concern than administration of anesthesia. Better understanding of the infant’s mechanism of temperature control has taught us that conservation of body heat is more important than application of external heat. Warm operating rooms and maximal covering of body, limbs, and head have been found to be most essential. Heating lamps are valuable as the operation is getting underway, water blankets now being regarded as of secondary importance. It was most fortunate for pediatric surgery that antibiotic therapy entered the picture at precisely the same time that many of the more heroic operations were first attempted, saving the lives of innumerable puny infants who would otherwise have been victims of postoperative infection. Although we still fuss about IV fluid therapy, great strides have been made in both the technic and management of this fundamental feature. The development of the present IV infusion apparatus was one of the

Measurements needed

Consciousness Pain Tissue oxygenation Blood volume

Cardiac output Pulmonary vascular resistance Intracranial pressure

most difficult and drawn-out problems of pediatric care, our first sets having consisted of an open-topped beaker with rubber tubing and a side-armed syringe fixed to the end. Intravenous fluids in infants were limited to dextrose and water, in minimal amounts, but proved adequate due to more generous use of whole blood. The “dry” regime of IV fluid therapy continued to dominate the scene for two decades, but recently has been threatened by the aggressive concept of abundant hydration. For infants who have passed the first 10 days of life, there has been wide acceptance of the guide established by Holliday and Segar (1957) ,a based on rate of metabolic activity adapted to weight (table 7). The major difference of opinion has been confined chiefly to management of the neonate, whom the “dries” prefer to maintain with 0 to 4 ml/kg/hr, while the “hydraters,” following the theory of Shires,7 go as high as 25 mllkglhr. In this situation, it seems that both concepts make the same mistake of suggesting one line of treatment for all patients. It seems far more rational to consider each neonate individually, as in table 8, for it becomes evident that the infant in danger TABLE 7 Intravenous Fluid Therapy Operative Support, Infants and Children‘ Weight [ k g )

Amount Iml/kg/hr)

- 10 10 - 20

4

0

Over 20

+ 60 + 1 for each kg over 20

40

2 for each kg over 10

Anesth An& 57534-646, 1978

Robert M. Smith TABLE 8

1 n travenous FI u id Allowance for Neonates (0 to 10 Days) Dry concept

Hydration concept (Shires)

0 - 4 ml/kg/hr

15 - 25 ml/kg/hr

Individualization concept ( r n l l k a l h r )

Cardiac, neurosurgical . . . . . . . . 2 Hernia, harelip . . . . . . . . . . . . . . 4 Intestinal obstruction . . . . . . . . . 6 - 8 Gastroschisis . . . . . . . . . . . . . . . . 8 - 10 Necrotizing enterocolitis . . . . . .15 - 20 of cardiac failure should be limited to a minimal amount of fluid, while others having normal water turnover or enjoying wider margins of error deserve increasing amounts, normal being considered 4 ml/kg/hr, while allowances of 6, 10, and 15 to 20 ml/kg/hr have been found appropriate for infants with increasing fluid demands, such as those with intestinal obstruction, gastroschisis, or necrotizing enterocolitis. In all situations reliance must be placed upon frequent evaluation of signs rather than upon use of any preset rules or formulae. Another step of great importance has been the development of the team concept in management of pediatric surgical patients. The early advances in pediatric surgery were credited almost entirely to the surgeons, with good reason. The value of anesthetic management next became evident. The development of recovery room care, and later the intensive therapy and respiratory therapy adjuncts, as well as experienced special nurses for continued care of infants following repair of tracheo-esophageal fistulae and similar lesions, all these combined to make an interlocking team in which all members were invaluable.

64 1

The development of ventilatory therapy has been slow and arduous but has finally reached a stage of considerable finesse. The recent introduction of intermittent mandatory ventilation (IMV) as a means for the gradual termination of controlled respiration solves one difficult problem, but leaves another, the endotracheal tube itself, which seems to be both the lifeline and the danger point of infant support. The addition of total parenteral alimentation in the postoperative care of small infants has resulted in marked reduction of surgical mortality. It has been of particular value in sustaining infants following reduction of intestinal obstruction. Ten to twenty days of IV support may be required before return of normal gastrointestinal function. Formerly many of these infants died of inanition and peritonitis. With parenteral alimentation, however, similar infants can be maintained in normal nutritional balance and death rarely occurs. Of the many advances in surgical technic that have helped the progress of pediatric anesthesia, the mesh closure of omphalocele and gastroschisis has been outstanding, for it has eliminated the hazards associated with forcing the viscera into the inadequate peritoneal cavity. Enough has been said of the accomplishments. Now it is time to look at a few of the weaknesses and failures related to pediatric anesthesia. One of my first statements was that there might be some misdirection in the work of the pediatric anesthesiologist. I was referring to the tremendous effort expended by all members of our teams in attempts to prolong the lives of patients who had no chance of surviving more than a few days, or else were so severely handicapped that life could only be a burden for the patients and all concerned with their physical or economic care.

The importance of postoperative nursing care becomes particularly evident when When an anencephalic monster is born, pediatric surgery is attempted in general and suburban hospitals. Frequently it is it is not allowed to survive. There have been possible to find surgeons and anesthesiolo- attempts to persuade parents to refuse opergists of sufficient skill to bring infants ation on infants with other overwhelming through standard operations in these loca- congenital anomalies, but these have had tions, but experienced nursing personnel is disappointing results. As shown in a recent apt to be lacking. Unless an anesthesiolo- survey by Todres and associates (1977),x gist is certain that expert aftercare is avail- there are so many complicating factors, inable for his patient, he may face the choice cluding the possibility of finding new forms of staying with the child himself or advis- of treatment, guilt complexes, religious and ing transportation of the child to a more racial restraints, and marital stresses, that little agreement is possible as to how to suitably equipped hospital.

642

Pediatric Anesthesia

regulate such problems. We are left in a position where we blindly strive for the survival of all living creatures, regardless of eugenics or economy. We spend millions on open-heart repair in children with Down’s syndrome, and race to the bedside of moribund infants every time they get into trouble. It would seem more constructive if we could spend greater effort on delivering superior care to children with high potential and reduce the excessive expenditure of time and personnel on the moribund, the totally demented, and the neonate with high thoracic meningocele and quadriplegia. One of the advances previously mentioned

was improved availability of pediatric anesthesiologists. This is only a half-truth. In spite of a numerical increase in our number, the demand still far exceeds the supply, and many posts have gone unfilled for several years. Lack of interest in this most pleasant and rewarding field is hard to explain, but reflects upon those of us who have been unsuccessful in stimulating enthusiasm for our special area. In our technical practices we have problems in nearly every aspect, including preoperative medication, induction, airway control, monitoring, and fluid therapy, as already mentioned. There are at present three problems that appear to be particularly important and deserve special emphasis. These are the questions of how much oxygen to administer to premature infants during surgery, the hazard of airway management, and the management of anxiety and suffering in the awake child.

Due to the increasing rate of survival of premature infants, the number of these scrawny patients coming to operation is steadily climbing. It is estimated that onethird of these infants have inguinal hernia, and our experience centainly bears this out. Experience with premature infants has brought us face-to-face with one of our greatest dilemmas- the problem of how much oxygen to allow them before, during, and after operation. All premature infants, and many small neonates, bear the double danger of developing respiratory distress syndrome (RDS) and retrolental fibroplasia (RLF) . Infants with RDS may require very high concentrations of oxygen to avoid hypoxic brain damage. On the other hand, there are many infants who, if given even slightly increased

Anesth Analg 57534.646, 1978

amounts of oxygen, will develop atelectasis, pulmonary irritation, and partial or total blindness. Our inability to determine the correct concentration of oxygen to give the individual infant keeps many in a zone of uncertainty for several weeks after birth. The problem is especially difficult because there is no safe area for all, for infants with RDS can become hypoxic while breathing 80% 02,while RLF can develop in other infants breathing 25 to 30% 02,and has been reported even in infants with tetralogy of Fallot, who presumably were hypoxic from birth. The use of air or nitrogen as a diluent for oxygen is now an accepted practice, but estimation of gas flows actually needed requires monitoring of arterial oxygen above and below the union of ductus arteriosus and aorta, and the level of tissue oxygenation. A serious problem in pediatric patients of all ages is that of the airway, truly the focal point of the child’s struggle for life. At present it appears that this problem is increasing rather than decreasing. In the operating room we have difficulty with obstruction during induction, and severe spasm on recovery. Intubation and extubation of the trachea are well known as the two greatest trouble sites in the course of the entire anesthetic procedure. The unfamiliarity of inexperienced anesthetists with the anatomy of normal infants and children leads to many preventable complications, while the high incidence of pathology in and about the airways of infants and children presents a continuing challenge to the most experienced. Tumors about the mouth, cystic hygroma, choanal atresia, PierreRobin syndrome, cleft lip and palate, Treacher-Collins syndrome, craniofacial synostosis Apert’s and Crouzons’ syndromes), and HunterHurler’s syndromes appear in the varied and continuing daily parade of pathology, while foreign bodies, fractures, and infections may be counted upon to enliven evenings and weekends.

We appear to have passed the most intense phase of our involvement in the emergency treatment of asthma. The management of epiglottitis and laryngotracheitis now presents the most critical need of acute airway care. The responsibility for definitive management of these patients has quite appropriately been turned over to pediatric anesthesiologists, who thus far appear to have handled the precarious situation with surprising success.

Anesth Analg 57:634-646, 1978

Robert M. Smith

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A particularly disturbing development is now seen in the growing incidence of tracheal stenosis and upper airway damage following treatment in pediatric treatment rooms, emergency areas, intensive care units, and especially in long-term management of infants in neonatology units.

to be one of the most-to-be-feared of the nonfatal complications that we encounter. The greater incidence of subglottic stenosis following intubation for the relatively unexciting laryngotracheobronchitis,or croup, has made treatment of this disease of more concern than that of epiglottitis, for which we now intubate without hesitation, experIn many situations this seems to stem ience having taught us that extubation can from the fact that trained anesthesiologists be expected within 48 to 72 hours, after are no longer being called upon to manage which there will be full recovery with no airway problems in these areas but have been complications. replaced by individuals lacking experience The third weakness, or, in this instance, in airway management. Problem of endotracheal intubation now appear to be a pop- frank failure, is neither life threatening nor ular topic in pediatric journals. One article scientific in nature, which may give some recently was concerned with an infant who explanation for its existence. This is our had been intubated (and reintubated) 329 failure to reduce the suffering of sick chiltimes during treatment for respiratory dis- dren, to appreciate their anxieties, or to tress syndrome. Another told of an infant answer many of their calls for help. whose esophagus had been perforated durRather than keeping abreast of the proing attempts to intubate the trachea.lo gress in other aspects of patient care, we While these particular complications prob- have allowed a gap to develop and enlarge ably should not be blamed on anesthesiolo- between methods of treatment and the varigists, they may be considered evidence that ous forms of distress, a few of which are we have not been successful in establishing listed in table 9. We are cognizant of the the importance of airway management pain of needles, but make slight attempt to among our medical colleagues. This is no- avoid their use when there are reasonable where more apparent than in the approach alternatives, often using a larger needle than to tracheal intubation in some neonatology necessary. Among the unpleasant experiunits, where medical students are allowed ences that appear most objectionable a t the repeated attempts a t intubation of prema- time are nasotracheal suction, prolonged ture infants, followed by further attempts by ventilatory support, and the pain of awakfirst-year medical residents, and then on up ening with tight casts compressing sensitive through gradually decreasing levels of inex- wounds. In follow-up studies, however, the perience, the gradation between bottom and remembrance of pain is reported less than the anguish of separation from parents, top sometimes being less than impressive. which appears to hurt after the wounds are The development of subglottic scarring healed. In the operating and recovery and stenosis, whether produced by anesthe- rooms, one certainly hears more cries for siologist or untrained personnel, threatens parents than cries of pain. This is not tissue TABLE 9 Distressing Experiences of Hospitalized Children

Physical pain Needles, dressings, wounds Discomfort Dizziness, nausea Examinations Restraints Casts, traction Drainage (chest, nasogastric, urethral) cannulae, infusion Nasotracheal suction Prolonged intubation, tracheostomy Mechanical ventilators

Emotional stress Separation from parents Unpleasant smells, tastes Vomitus, dressings Medicines, anesthetics

Unpleasant sounds Screaming patients Clattering instruments Disturbing sights Bleeding, disfigured, crippled, comatose, moribund, and “cardiac arrest” patients Masked, gowned personnel

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pathology, but is suffering,which leaves lasting effect, and which we obviously are not handling effectively. Many children coming to the operating room for the first time suffer from fear of the unknown; others have established fears suggested by friends, books, or television. Adolescents have been reading “Coma” and are afraid that their bodies will be stored for future use of spare parts. One television program recently portrayed a patient dying from halothane hepatotoxicity, complete with futile cardiac massage. Parents communicate concern to their children. It has been surprising to find that 90% of the parents who wish to be with their children prior to anesthesia are parents of children coming for tonsillectomy or hernia repair while children about to have cardiac or other extensive procedures usually come unattended. We believe that this has been due to greater effort to orient cardiac and orthopedic patients and parents, who have had considerable contact with hospital and personnel long before the operation. In 1938 Ralph Waters wrote one of the first articles on pediatric premedication, suggesting morphine and scopolamine.‘’ In spite of the fact that more has been written about premedication than any other phase of pediatric anesthesia, very little progress has been made in the intervening 40 years. Innumerable agents and combinations have been tried, usually on an unsound investigative basis, with 60 to 70% success, the remainder being over- or undersedated. The logic of sedation has been irrational, since dosage has been chosen by the child’s weight or age, rather than by the degree of his anxiety. A lethargic, fat .i-year-old, by such standard, might receive twice the dose of an anxious, scrawny, hyperactive child who is literally climbing the walls. Agents used for sedation are less than predictable, the much advertised tranquilizing agents proving less reliable than barbiturates, with great variability in patient response ar,d a number of side effects, diazepam producing apnea, hydroxyzine producing fever, and compazine producing hypotension. Our traditional method of injecting sedatives by needle gives rise to some of the child’s most lasting impressions of hospital life, and the dry, sour mouth caused by atropine is an added and entirely unnecessary discomfort for the waiting, hungry child. Our lack of success in sedating pediatric

Anesth Anal# 57.634-646, 1978

patients is demonstrated by the wide divergence of approaches currently employed. These include heavy sedation, aiming at having all children asleep prior to anesthetic induction; light sedation, to provide a quiet, but not necessarily sleeping child; and no sedation, relying on informal play areas and personnel to fortify and distract the child’s attention until it is their turn to be spirited away into the operating room. While each of these approaches has certain advantages, none can be used for all children. We seldom take into account the fact that a child’s anxiety varies with his age, his disease, the number of previous operations, type of parent, and other factors, and must be considered on an individual basis, one child of high anxiety level needing 2 to 3 times the usual sedative dose, while another child might need none. It is no wonder that we score poorly in controlling children’s emotions. Faced with these problems, our best approach would appear to be to attempt more rational use of presently available drugs, and continue the search for better sedatives, but of more importance, reduce our reliance upon use of sedatives by putting more effort into controlling children’s anxieties by more personal contact with the children and their parents. When sedatives are employed, the first rational steps in their use would include elimination of needles, delaying use of atropine until the child is asleep, and greater individualization of dosage in relation to level of anxiety. Of the agents currently used, pentobarbital appears more predictable than most, and without dangerous side effects. The excitement often seen with pentobarbital is not remembered by the child, and does not contribute to postanesthetic anxieties. It does not require injection. Average dosages are shown in table 10. Morphine continues to be the best sedative agent for children. Narcotics are actually safer than many sedatives, for narcotics can be reversed quite effectively, whereas there is no way to control the action of most sedatives currently used. The easiest improvement to carry out among the many inadequacies related to preoperative sedation is the elimination of the dry mouth that follows atropine. This is possible either by delaying use of atropine until the child is asleep, or doing away with it entirely.

Anevth Analg 57:634-64fi, 1978

Robert M. Smith

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TABLE 10 Premedication: Sedation Without Depression

1. Avoid needles

2. Avoid dry mouth

3. Individualize dosage

Pentobarbital ( NembutaP) Standard dose: 4 mg/kg, PO or pr (max dose 120 mg). Recommended dose (Smith): 0, %, 1, or 2x standard dose as needed. Give 45 min before early case, 2-3 hr before late case. Repeat in 1 hr if necessary. Morphine: 0.1 mg/kg SC, if indicated, 45 min preop. Atropine: 0.1-0.4 mg IV or IM, after child is asleep. The increasing desire of parents to be with their children a t all times and to come to, and even into, the operating room with their children has further complicated the preoperative management of children. Many of these parents, highly emotional themselves, continually communicate their anxiety to their children, actually preventing them from settling down by constant attention and fondling. After bidding tearful last farewells as the child is wheeled off for his tonsillectomy, the parents may believe that they have kept faith with their child by staying with him until the last, but they actually have added considerably to his emotional stress.

If all parents who wish to stay with their children could learn to sit quietly beside the child‘s bed as sedation takes effect, and withdraw before the child is taken to the operating room, they would be justified in feeling that they had been of some help. Many pediatric anesthesiologists have yet to learn that the parent often needs more moral support than the child, and that attempts to gain the child’s confidence are useless unless the parent’s confidence has already been won. Finally, what can be said about the future of pediatric anesthesia? This is a difficult question. Both pediatricians and pediatric surgeons are concerned about the survival of their specialties. Whatever their fate, that of pediatric anesthesia is sure to be a t least as dark. The reason for the concern lies in a combination of factors. The birth rate is declining at an easily perceptible rate. Improved health care and preventive medicine should curtail the incidence of many surgical lesions occurring in infants and children. Surgery of congenital cardiac defects is believed to have peaked already. Of considerably greater effect on the growth of pediatric surgery and anesthesia

is the dilution of patient care. With the continual training of more pediatric surgeons, many must move away from original teaching centers and set up practices at outside, or suburban, hospitals where they perform many of the operations previously restricted to the centers. With increasing numbers of surgeons and decreasing numbers of infants, such dilution will, and already has, so reduced the numbers of operations on small infants that there is inadequate teaching material either for the training of the inexperienced or for maintenance of skill of those previously trained in either surgery or anesthesiology. Surgeons have already taken steps to limit the number entering training each year, but the main hope for surgeons and anesthesiologists lies in the development of centers properly distributed about the nation, and referral of patients to these areas by highly organized systems of triage and transportation. Neonatologists, feeling the same concern, have made successful strides to concentrate their efforts, but surgeons have not been able to promote the system as yet, and anesthesiologists have not entered the contest. Important economic factors affect both the tendency to dilute and the tendency to centralize our practice. Patients are drawn to outlying hospitals by surgeons working outside the cities, and by reduced costs of hospitalization. For the smaller hospitals, adequate facilities for specialized pediatric surgery impose increasing financial burdens which the hospitals cannot afford and the government refuses to subsidize. Although this should send patients back to the center hospitals, centralization has not started to show the strength required to ensure the survival of our practice. It is interesting to try to picture the type of pediatric surgery that lies ahead. There is obvious advantage in correcting deformi-

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ties as early as possible, whether they require cardiac, orthopedic, general, genitourinary, or plastic procedures. Although the total number of infants born will decrease, the higher incidence of premature babies will probably result in an increased incidence of those born with defects. Undoubtedly one will see not only more complicated operations being performed, but also an increase in the frequency with which they are performed. Transplantation of heart, lungs, and other organs should be standardized, as well as replacement of bones, joints, and muscles in treatment of tumors and major injuries. Surgery for correction of metabolic diseases, now in its infancy, should develop in the near future, and involve new physiologic problems for the anesthesiologist. Among many procedures of the future, reestablishment of the patency of the trachea, whether by graft, reimplant, or other means, looms as one of the most urgent needs, and one that will require considerable input on the part of the anesthesiologist both in the initial procedure and in the aftercare of the child. With such goals to anticipate, it is definitely to be hoped that pediatric anesthesiology can survive and meet the challenge.

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REFERENCES 1. Beecher HK, Todd DP: A study of the deaths associated with anesthesia and surgery. Ann Surg 140:2-34, 1954 2. Smith RE3, Petrusak J: Letter to the Editor. Tonsillectomy and mortality. JAMA 227: 557, 1974

3. Koop CE, Schnaufer L, Broennle AM: Esophageal atresia and tracheoesophageal fistula: supportive measures that affect survival. Pediatrics 54: 558-564, 1974

4. Elwyn RA: Personal communication, 1978 5. Smith RM: Anesthesia for Infants and Children. Fourth edition. St. Louis, C.V. Mosby, in press 6. Holliday MA, Segar WE: The maintenance need for water in parenteral fluid therapy. Pediatrics 19:823-831, 1957

7. Shires GT, Williams J, Brown F: Acute change in extracellular fluids associated with major surgical procedures. Ann Surg 154:803-810, 1961 8. Todres D, Krane D, Howell MC, et al: Pediatrician’s attitude affecting decision-making in defective newborns. Pediatrics 60:197-202, 1977

9. Stein RT, Wall P, Kaufman RA, et al: Neonatal anterior esophageal perforation. Pediatrics 60: 744-746, 1977 10. Strong RM, Passy V: Endotracheal intubation: complications in neonates. Arch Otolaryngol 103:329-335, 1977 11. Waters RM: Pain relief for children. Am J Surg 39:470-475, 1938

PEEP A N D I N T R A C R A N I A L PRESSURE Positive end-expiratory pressure ( P E E P ) was required i n 1 2 head-injured patients i n whom intracranial pressure ( I C P ) monitoring had been previously established. In six, ICP increased by 10 m m H g or more as 4 t o 8 c m H,O of PEEP were administered. I n 10 patients the m e a n arterial pressure decreased during PEEP. Before PEEP, the m e a n cerebral perfusion pressure ( C P P = BP - I C P ) was above 50 m m H g in all patients. The CPP was less than 50 m m H g i n 6 patients given PEEP. Neurological deterioration occurred i n 2 patients during PEEP therapy. In head-injured patients, optimal titration of PEEP therapy should include I C P measurement a n d / o r continuous evaluation of neurologic status. (Shapiro H M , Marshall LF: Intracranial pressure responses to P E E P in head-injured patients. J Trauma 18:254-256, 1978)