Anesthesia for Congenital Heart Disease

Stephen A. Stayer, Isobel A. Russell, Emad B. Mossad

• Publisher: Wiley-Blackwell
• Year: 2011
• ISBN:
  9781444357431
• Edition: 2
• Topic: Medicine
• Subtopic: Cardiology

This timely revision reflects the rapid advances in surgery and anesthesia for congenital heart disease that have occurredin recentyears, including neonatal cardiac surgery and anesthesia, treatment of single ventricle patients, new diagnostic modalities, and developments in the catheterization laboratory. Newchapters address mechanical support of the circulation, embryology, and quality/outcomes management.

1

History, Education, Outcomes, and Science,

1

History of anesthesia for congenital heart disease

Dolly D. Hansen, M.D. and Paul R. Hickey, M.D.

Children’s Hospital, Boston and Harvard Medical School, Boston, Massachusetts, USA

Introduction

The first years: 1938–1954

The heart–lung machine: 1954–1970

The era of deep hypothermic circulatory arrest and the introduction of PGE₁: 1970–1980

PDA and the introduction of PGE₁

The story of HLHS: 1980–1990

Fontan and the catheterization laboratory: 1990–2000

2000–2010 and the future

References

Introduction

Over the last 65 years, pediatric cardiac anesthesia has developed as a subspecialty of pediatric anesthesia, or a subspecialty of cardiac anesthesia, depending on one’s perspective. It is impossible to describe the evolution of pediatric cardiac anesthesia without constantly referring to developments in the surgical treatment of congenital heart disease (CHD) because of the great interdependency of the two fields. As pediatric anesthesia developed over the years, surgical treatments of children with CHD were invented, starting with simple surgical ligation of a patent ductus arteriosus (PDA) to sophisticated, staged repair of complex intracardiac lesionsin low-birth-weight neonates requiring cardiopulmonary bypass (CPB) and circulatory arrest. Practically, every advance in surgical treatment of CHD had to be accompanied by changes in anesthetic management to overcome challenges that impeded successful surgical treatment or mitigated morbidity associated with surgical treatment.

This history will mostly be organized around the theme of how anesthesiologists met these new challenges using the then-available anesthetic armamentarium. The second theme running through this story is the slow change of interest and focus from just events in the operating room (OR) to perioperative care in its broadest sense, including perioperative morbidity. The last theme is the progressive reduction in the age of patients routinely presenting for anesthesia and surgery from the 9-year-old undergoing the first PDA ligation in 1938 [1] to the fetus recently reported in the New York Times in 2002 who had aortic atresia repaired in utero [2]. Interestingly, both patients had had their cardiac procedures at the same institution.

This story will be told working through the different time frames—the first years: 1938–1954; CPB and early repair: 1954–1970; deep hypothermic circulatory arrest (DHCA) and introduction of prostaglandin E₁ (PGE₁): 1970–1980; hypoplastic left heart syndrome (HLHS): 1980–1990; refinement and improvement in mortality/morbidity: 1990–2000.

The first years: 1938–1954

These years began with the ligation of the PDA and continued with palliative operations. The first successful operation for a CHD occurred in August 1938 when Robert E. Gross ligated the PDA of a 9-year-old girl. The operation and the postoperative course were smooth, but because of the interest in the case, the child was kept in the hospital until the 13th day. In the report of the case, Gross mentions that the operation was done under cyclopropane anesthesia, and continues: “The chest was closed, the lung being re-expanded with positive pressure anesthesia just prior to placing the last stitch in the intercostal muscles.”

A nurse using a “tight-fitting” mask gave the anesthetic. There was no intubation and of course no postoperative ventilation. The paper does not mention any particular pulmonary complications, so it cannot have been much different from ordinary postoperative course of the day [1].

In 1952 Dr Gross published a review of 525 PDA ligations where many, if not all, of the anesthetics were administered by the same nurse anesthetist, under surgical direction [3]. Here he states: “[F]ormerly we employed cyclopropane anesthesia for these cases, but since about half of the fatalities seemed to have been attributable to cardiac arrest or irregularities under this anesthetic, we have now completely abandoned cyclopropane and employ ether and oxygen as a routine.” It is probably correct that cyclopropane under these circumstances with insufficient airway control were more likely to cause cardiac arrhythmias than ether. An intralaryngeal airway was used which also served “to facilitate suction removal of any secretions from the lower airway” (and we may add, the stomach). Dr Gross claims that the use of this airway reduced the incidence of postoperative pulmonary complications. Without having a modern, rigorous review of this series, it is hard to know what particular anesthetic challenges other than these confronted the anesthetist, but we may assume that intraoperative desaturation from the collapsed left lung, postoperative pulmonary complications, and occasional major blood loss from an uncontrolled, ruptured ductus arteriosus were high on the list.

The next operation to be introduced was billed as “corrective” for the child with cyanotic CHD and was the systemic to pulmonary artery shunt. The procedure was proposed by Helen Taussig as an “artificial ductus arteriosus” and first performed by Albert Blalock at Johns Hopkins Hospital in 1944. In a very detailed paper, Drs Blalock and Taussig described the first three patients to undergo the Blalock–Taussig shunt operation. Dr Harmel anesthetized the first and third patients, using ether and oxygen in an open drop method for the first patient and cyclopropane through an endotracheal tube for the third patient. The second patient was given cyclopropane through an endotracheal tube by Dr Lamont. Whether patient #1 and #3 were intubated is unclear, but it is noted that in all three cases positive pressure ventilation was used to reinflate the lung [4]. Interestingly, in this early kinder and gentler time, the surgical and pediatric authors reporting the Blalock–Taussig operation acknowledged by name the pediatricians and house officers who took such good care of the children postoperatively but still did not acknowledge in their paper the contribution of the anesthesiologists Lamont and Harmel.

Although intubation of infants was described by Gillespie as early as 1939, it is difficult to say exactly at what time intubations became routine [5].

Drs Harmel and Lamont, who were anesthesiologists, reported in 1946 on their anesthetic experience with 100 operations for congenital malformations of the heart “in which there is pulmonary artery stenosis or atresia.” They reported 10 anesthetic-related deaths in the series, so it is certain that they encountered formidable anesthetic problems in these surgical procedures [6]. This is the first paper we know of published in the field of pediatric cardiac anesthesia.

In 1952 Damman and Muller reported a successful operation in which the main pulmonary artery was reduced in size and a band placed around the artery in a 6-month-old infant with single ventricle (SV). It is mentioned that morphine and atropine were given preoperatively, but no further anesthetic agents are mentioned. At that time infants were assumed to be oblivious to pain so we can wonder what was used beyond oxygen and restraint [7].

Over the next 20 years many palliative operations for CHD were added and a number of papers appeared describing the procedures and the anesthetic management. In 1948 McQuiston described the anesthetic technique used at Children’s Memorial Hospital in Chicago [8]. This is an excellent paper for its time, but a number of the author’s conclusions are erroneous, although they were the results of astute clinical observations and the current knowledge at the time. The anesthetic technique for shunt operations (mostly Potts’ anastomosis) is discussed in some detail, but is mostly of historical interest today. McQuiston explained that he had no experience with anesthetic management used in other centers, such as the pentothal–N₂O–curare used at Minnesota or the ether technique used at the Mayo clinic. McQuiston used heavy premedication with morphine, pentobarbital and atropine, and/or scopolamine; this is emphasized because it was important “to render the child sleepy and not anxious.” The effect of sedation with regard to a decrease in cyanosis (resulting in making the child look pinker) is noted by the authors. They also noted that children with severe pulmonic stenosis or atresia do not decrease their cyanosis “because of very little blood flow,” and these children have the highest mortality.

McQuiston pointed out that body temperature control was an important factor in predicting mortality and advocated the use of moderate hypothermia, i.e., “refrigeration” with ice bags, because of a frequently seen syndrome of hyperthermia. McQuiston worked from the assumption that hyperthermia is a disease in itself, but did not explore the idea that the rise in central temperature might be a symptom of low cardiac output with peripheral vasoconstriction. Given what we now know of shunt physiology, it is interesting to speculate that this “disease” was caused by pulmonary hyperperfusion after the opening of what would now be considered as an excessively large shunt, stealing a large portion of systemic blood flow.

In 1950 Harris described the anesthetic technique used at Mount Zion Hospital in San Francisco. He emphasized the use of quite heavy premedication with morphine, atropine, and scopolamine. The “basal anesthetic agent” was Avertin (tribromoethanol). It was given rectally and supplemented with N₂O/O₂ and very low doses of curare. Intubation was facilitated by cyclopropane. The FIO₂ was changed according to cyanosis, and bucking or attempts at respiration were thought to be due to stimulation of the hilus of the lung. This was treated with “cocainization” of the hilus [9].

In 1952 Dr Robert M. Smith discussed the circulatory factors involved in the anesthetic management of patients with CHD. He pointed out the necessity to understand the pathophysiology of the lesion and also “the expected effect of the operation upon this unnatural physiology.” That is, he recognized that the operations are not curative. The anesthetic agents recommended were mostly ether following premedication.

While most of these previous papers had been about Tetralogy of Fallot (TOF), Dr Smith also described the anesthetic challenges of surgery for coarctation of the aorta. He emphasized the hypertension following clamping of the aorta and warned against excessive bleeding in children operated on at older ages using ganglionic blocking agents. This bleeding was far beyond what anesthesiologists now see in patients operated on at younger ages, before development of substantial collateral arterial vessels [10].

The heart–lung machine: 1954–1970

From 1954 to 1970 the development of what was then called the “heart–lung machine” opened the heart to surgical repair of complex intracardiac congenital heart defects. At the time, the initial high morbidity of early CPB technology seen in adults was even worse in children, particularly smaller children weighing less than 10 kg. Anesthetic challenges multiplied rapidly in association with CPB coupled with early attempts at complete intracardiac repair. The lung as well as the heart received a large share of the bypass-related injuries leading to increased postoperative pulmonary complications. Brain injury began to be seen and was occasionally reported, in conjunction with CPB operations, particularly when extreme levels of hypothermia were used in an attempt to mitigate the morbidity seen in various organ systems after CPB.

In Kirklin’s initial groundbreaking report to fintracardiac surgery with the aid of a mechanical pump oxygenator system at the Mayo Clinic, the only reference to anesthetic management is a brief remark that ether and oxygen were given [11]. In Lillehei’s description of direct vision intracardiac surgery in man using a simple, disposable artificial oxygenator, there is no mention of anesthetic management [12]. What strikes a “modern” cardiac anesthesiologist in these two reports is the high mortality: 50% in Kirklin’s series and 14% in Lillehei’s series. All of these patients were children with CHD ranging in age from 1 month to 11 years. Clearly, such mortality and the associated patient care expense would not be tolerated today.

At that time, pediatric anesthesia was performed with open drop ether administration and later with ether using different non rebreathing systems. Most anesthetics were given by nurses under the supervision of the surgeon. The first physician anesthetist to be employed by a Children’s Hospital was Robert M. Smith in Boston in 1946.

The anesthetic agent to come into widespread use after ether was cyclopropane; in most of the early textbooks, it was the recommended drug for pediatric anesthesia. Quite apart from being explosive, cyclopropane was difficult to use. It was obvious that CO₂ absorption was necessary with cyclopropane to avoid hypercarbia and acidosis, which might precipitate ventricular arrhythmias. However, administration with a Waters’ absorber could be technically difficult especially as tracheal intubation was considered dangerous to the child’s “small, delicate airway.”

In all the early reports it is noted or implied that the patients were awake (more or less) and extubated at the end of the operation. In the description of the postoperative course, respiratory complications were frequent, in the form of either pulmonary respiratory insufficiency or airway obstruction. This latter problem was probably because “the largest tube, which would fit through the larynx” was used. Another reason may have been that the red rubber tube was not tissue tested. The former problem was probably often related to the morbidity of early bypass technology on the lung.

Arthur S. Keats, working at the Texas Heart Institute and Texas Children’s Hospital with Denton A. Cooley, had much experience with congenital heart surgery and anesthesia from 1955 to 1960, and provided the most extensive description of the anesthetic techniques used in this era [13, 14]. He described anesthesia for congenital heart surgery without bypass in 150 patients, the most common operations being PDA ligation, Potts operation, atrial septectomy (Blalock–Hanlon operation), or pulmonary valvotomy. Premedication was with oral or rectal pentobarbital, chloral hydrate per rectum, intramuscular meperidine, and intramuscular scopolamine or atropine. Endotracheal intubation was utilized, and ventilation was assisted using an Ayres T-piece, to-and-fro absorption system, or circle system. Cyclopropane was used for induction, and a venous cutdown provided vascular access. Succinylcholine bolus and infusion were used to maintain muscle relaxation. Light ether anesthesia was used for maintenance until the start of chest closure, and then 50% N₂O used as needed during chest closure. Of note is that the electrocardiogram, ear oximeter, and intra-arterial blood pressure recordings were used for monitoring during this period, as well as arterial blood gases and measurements of electrolytes and hemoglobin. The next year he published his experiences with 200 patients undergoing surgery for CHD with CPB, almost all of whom were children. Ventricular septal defect (VSD), atrial septal defect (ASD), tetralogy of Fallot (TOF), and aortic stenosis were the most common indications for surgery. The anesthetic techniques were the same as above, except that d-tubocurare was given to maintain apnea during bypass.

Perfusion rates of 40–50 mL/kg/min were used in infants and children, and lactic acidemia after bypass (average 4 mmol/L) was described. No anesthetic agent was added during bypass, and “patients tended to awaken during the period of bypass,” but apparently without recall or awareness. Arrhythmias noted ranged from frequent bradycardia with cyclopropane and succinylcholine to junctional or ventricular tachycardia, ventricular fibrillation (VF), heart block, and rapid atrial arrhythmias. Treatments included defibrillation, procainamide, digitalis, phenylephrine, ephedrine, isoproterenol, and atopine. Eleven of 102 patients with VSD experienced atrioventricular block. Epicardial pacing was attempted in some of these patients but was never successful. Fresh citrated whole blood was used for small children throughout the case, and transfusion of large amounts of blood was frequently necessary in small infants. Mortality rate was 13% in the first series (36% in the 42 patients less than 1-yr-old) and 22.5% in the second series (47.5% in the 40 patients less than 1-yr-old). Causes of death included low cardiac output after ventriculotomy, irreversible VF, coronary air emboli, postoperative atrioventricular block, hemorrhage, pulmonary hypertension, diffuse atelectasis, and aspiration of vomitus. No death was attributed to the anesthetic alone. Reading these reports provides an appreciation of the daunting task of providing anesthesia during these pioneering times.

Tracheostomy after cardiac operations was not unusual and in some centers it was done “prophylactically” a week before the scheduled operation. These practices were certainly related to primitive (in present terms) techniques and equipment used for both endotracheal intubation and CPB. Postoperative ventilatory support did not become a routine until later when neonatologists and other intensive care specialists had proven it could be done successfully. Successful management of prolonged respiratory support was first demonstrated in the great epidemics of poliomyelitis in Europe and the USA in 1952–1954 [15].

Halothane was introduced in clinical practice in the mid-1950s and it became rapidly the most popular agent in pediatric anesthesia, mostly because of the smooth induction compared to the older agents. Halothane was also widely us...

Table of contents

• Cover
• Dedication
• title
• Copyright
• Contents
• List of Contributors
• Preface
• Acknowledgements
• Part 1: History, Education, Outcomes, and Science
• Part 2: Monitoring
• Part 3: Preoperative Considerations
• Part 4: Management
• Part 5: Anesthesia for Specific Lesions
• Part 6: Anesthesia Outside the Cardiac Operating Room
• Appendix : Texas Children’s Hospital Pediatric Cardiovascular Anesthesia Drug Sheet (March 2009)
• Index
• Colour plate