The Heart Center - Arkansas Children's Hospital

www.archildrens.org

Vol 1 Issue 6	July 2006
Inside this issue
Post-Surgical Palliation Home Surveillance
Advanced Practice Nursing at Arkansas Children's Hospital
Pain Management after Heart Surgery in the Heart Center
What is Transposition of the Great Arteries
Spotlight on Jim Bodtke, RDCS

Post-Surgical Palliation Home Surveillance

DeeAnn Martin, R.N.; Cardiac Surgery Speciality Nurse, Arkansas Children's Hospital

Hypoplastic left heart syndrome (HLHS) is a constellation of defects involving stenosis or atresia of the mitral valve, hypoplasia of the systemic or left ventricle, severe aortic valve hypoplasia with atresia, and hypoplasia of the ascending aorta. Surgical palliation for infants born with HLHS consists of Stage 1 Palliation (S1P). Also known as the Norwood procedure, S1P is the construction of an unobstructed outlet for systemic cardiac output from the right ventricle, and adequate pulmonary blood flow through a controlled shunt.

In the recent past, late interim mortality between S1P and Stage 2 Palliation (S2P) ranged from 10 percent to 15 percent. The Norwood population is considered to be at increased risk for sudden death from a combination of physiologic variances. Worsening systemic oxygenation and acute dehydration are variables which contribute to increased risk for sudden death. Home surveillance programs, consisting of daily oxygen saturation monitoring and weight checks, have been shown to decrease the risk of late interim mortality between S1P and S2P from 10 percent to 15 percent to 0 percent for infants with HLHS.

History of the Program
Since 2002, the ACH Cardiac Surgery department has monitored each post-Norwood baby with a home surveillance program. Beginning in 2006, the program was expanded to include all babies with univentricular hearts palliated with systemic to pulmonary artery shunts. Home pulse oximeters and baby scales are provided by the family’s insurance company and placed in each baby’s home. The primary caregiver is taught how to correctly obtain an accurate daily oxygen saturation reading and weight. These measurements are recorded on a provided form and faxed weekly to the Cardiac Surgery department.

Each baby’s growth and oxygen saturation trends are monitored closely. This information is provided to the baby’s primary cardiologist and a registered dietician participating in the program. Thus ongoing assessment of each palliated infant is achieved by three collaborating services. Patient participation in the home surveillance program ceases with achievement of stage 2 palliation.

Obtaining home monitoring equipment is becoming difficult as more third-party payers are denying coverage. Therefore, ACH CVICU is providing baby scales as needed for caregivers’ use. We would be remiss if, after performing advanced surgical intervention and postoperative care, we did not enable the primary caregivers to continue high quality care for their babies. We are committed to reducing interim morbidity and mortality, thus optimizing each palliated baby’s life course.

Advanced Practice Nursing at Arkansas Children's Hospital

Michelle McDonnell, APN; CVICU, Arkansas Children's Hospital

An Advanced Practice Nurse (APN) is a registered nurse who has completed an advanced nursing educational program, usually at the graduate level, and holds certification from a nationally recognized certifying body. There are several specialty areas in which an APN can obtain certification, including pediatrics. Currently in the Heart Center, there are five certified Pediatric Nurse Practitioners (PNP), two of whom have obtained additional certification as Pediatric Acute Care Nurse Practitioners. All of the current PNPs obtained their graduate degree from UAMS and have previous pediatric nursing experience at ACH. In addition to formal educational training, PNPs in the Heart Center complete six months of orientation, working closely with an experienced nurse practitioner to learn the ICU role.

PNPs are able to directly influence patient care through the medical management of pediatric patients, monitoring and ensuring the quality of health care practice and providing family-centered care. In addition, they influence practice through staff education, consultation, research and research dissemination. In the Heart Center, PNPs work in collaboration with Pediatric Cardiologists and Intensivists in managing congenital cardiac patients after surgery.

In collaboration with these physicians, PNPs are able to perform history and physical examinations, evaluate clinical data and make appropriate medical decisions, and perform procedures including management and removal of arterial and central venous lines, venous and arterial puncture, endotracheal intubation, umbilical catheter insertion, needle thoracentesis, defibrillation or cardioversion, removal of chest tubes, pacing wires, and peritoneal catheters, and lumbar punctures. The CVICU team, composed of the attending physician, unit
pharmacist and nurse practitioner, evaluates and assesses each patient and develops a plan of care for the day. In addition to taking care of all cardiac ICU patients, the team is also responsible for any cardiac ECMO patients.

The practitioner team is able to cover the unit seven days a week with some night coverage, lending continuity to the CVICU team. Interacting with families and patients on a daily basis enables the practitioners to facilitate education and discharge planning based on the individual needs of the patient. In addition, the practitioner team works closely with other team members including the unit pharmacist, social worker, child life specialist, speech/physical/and occupational therapists to maximize functional abilities and prevent or minimize disabilities.

Pain Management after Heart Surgery in the Heart Center

Laura Morales, Pharm. D.; Clinical Coordinator of the Pharmacy, Arkansas Children's Hospital

At Arkansas Children’s Hospital Heart Center, pain control is a vital element of the healing process after surgery. The pain response includes an increase in circulating levels of catecholamines (adrenalin type chemicals) and hormones leading to tachycardia (increased heart rate), hypertension (increased blood pressure), increased oxygen consumption, hypercoagulability (increased blood clotting), immunosuppression (decreased ability to fight infection) and catabolism (protein breakdown). Also, lung recovery can be affected when coughing or physical activity is delayed due to pain.

All patients, including the tiniest newborns, receive analgesics (pain medicines) with careful monitoring. Narcotic analgesics such as morphine or fentanyl are first given in the operating room prior to surgery and continued afterward. Doses are adjusted as needed. While intubated (on a breathing machine), most patients also receive a benzodiazepine such as midazolam or lorazepam to lessen their anxiety, promote rest, minimize movement and provide amnesia. Both types of medications (narcotics and benzodiazepines) may need to be decreased before extubation (removal of a breathing machine) as they can suppress the patient’s ability to breath on their own. A new medication that offers sedation with some analgesia but without respiratory depression is dexmedetomidine (Precedex). It is not a narcotic or benzodiazepine but is an alpha 2 agonist (related to clonidine but more selective) given as a continuous infusion.

Some patients may be candidates for regional (or localized) pain control measures such as epidural or nerve blocks where local anesthetics and/or narcotics are given into tissue spaces by an anesthesiologist providing analgesia with fewer side effects.

Pain Management Administering
Intramuscular injections are painful and are not used for post operative pain control.
Instead, patients receive analgesics through their IV (or intravenous line) either as frequent injections or a continuous infusion. When patients are able to resume intake of liquids, oral pain medications such as acetaminophen with codeine (Tylenol with codeine) or oxycodone (Percocet) are given routinely around the clock or on an as needed basis, depending on the comfort level of the patient. Constipation is common and can be treated or prevented with laxatives.

Patients 8 years or older may be candidates for “PCA” (or patient controlled analgesia). A special IV pump is programmed so the patient can push a button at their bedside allowing the pump to give an IV dose of analgesic (usually morphine) every few minutes. Sometimes, this is in addition to a small continuous infusion called a background dose. This allows the patient to be more in control of their analgesia once they have awakened from general anesthesia and are alert. Ketorolac (Toradol) is an analgesic similar to ibuprofen (Motrin) but given through IV. It is useful in patients who are extremely sleepy or nauseated from narcotics. Ketorolac is FDA approved for use (in single doses) in patients over 2 years of age. Patients must be stable from risks of bleeding with normal renal function for ketorolac to be considered.

Patients who are critically ill and remain intubated for over a week while receiving morphine, fentanyl, midazolam or lorazepam can develop tolerance to these agents. Thus, increased doses are needed to provide the same effect as before. However, once patients are improving, these agents can be weaned with dosages decreased slowly to prevent withdrawal symptoms of irritability, tremor, vomiting, sweating, fever or diarrhea. This is termed “physical dependence” and occurs in all patients, regardless of age, who receive these agents for prolonged periods. We treat this by tapering morphine or fentanyl and/or switching to an equivalent dose of oral methadone. IV midazolam or lorazepam doses are converted to oral lorazepam. Doses are decreased every few days and patients are monitored for any further symptoms.

About Addiction
Tolerance and physical dependence alone do not define “addiction,” which parents may be concerned about until they are educated on the difference. Addiction is a chronic disease, with behaviors of using a substance in the face of adverse consequences with loss of control (compulsive use) and a preoccupation with use (cravings). Genetic, psychosocial and environmental factors must all co-exist for addiction to occur in any individual. It is not uncommon to see physical dependence and tolerance from a prolonged recovery, but addiction is quite rare. Emotional distress from inadequate analgesia is not something we want our patients or parents to experience. Pain-free recovery after major surgery is not a reality yet, but minimizing discomfort for our patients is certainly achievable now.

What is Transposition of the Great Arteries?

Michiaki Imamura, M.D., Ph.D.; Pediatric Cardiac Surgeon, Arkansas Children's Hospital; Assistant Professor, Department of Surgery, University of Arkansas for Medical Sciences College of Medicine

Our hearts have four chambers inside them (Fig. 1). Under normal conditions, the blood from the body comes back to the heart into the right atrium. This blood is relatively blue (deoxygenated) blood. This blue blood goes to the right ventricle, which pumps the blood to the lungs through the pulmonary artery. In the lungs, this blood becomes red (oxygenated) blood and returns to the left atrium. This red blood goes to the left ventricle which pumps it to the whole body through the aorta. The aorta and the pulmonary artery, the two major arteries carrying blood away from the heart, are referred to as the “Great Arteries.”

However, in a patient with transposition of the Great Arteries, the aorta and the pulmonary artery are switched, and these vessels arise from the wrong ventricle (Fig. 2). Therefore, blue blood comes back from the body and goes to the body again, while the red blood comes back from the lungs and goes to the lungs again.

In the case of transposition of the great arteries, additional intracardiac anomalies occur, such as ventricular septal defect, pulmonary valve stenosis, pulmonary artery stenosis, aortic stenosis, coarctation of the aorta, hypoplasia of the aortic arch and interrupted aortic arch. In the presence of a ventricular septal defect and pulmonary valve stenosis, a different surgical treatment is required. The ventricular septal defect is the most common additional anomaly, except for patent duct arteriosus and an atrial septal defect. In the presence of other anomalies, treatment is chosen for transposition of the great arteries.

Signs and Symptoms
Babies with transposition are usually diagnosed as neonates due to cyanosis – blue coloring of skin, lips and nails. Cyanosis develops in the presence of poor oxygenation of the red blood cells. Occasionally, a baby with transposition receives a large amount of pulmonary blood flow and does not show prominent cyanosis. Without surgical intervention, more than half of infants with transposition will die in the first month of life, and 90 percent will die in the first year.

Diagnosing
Definitive diagnosis is made by echocardiography. Recently, many patients have been diagnosed before birth by fetal echocardiography.

Treatment
If there is no shunting (septal defects) inside the heart, a baby with this disease is not able to survive. This shunting generally occurs due to a hole between atriums (an ASD). However, some babies do not have this shunt, which makes their early diagnosis critical in order to prevent early death. In order to obtain adequate mixing inside the heart, a hole between the right and left atrium is created or enlarged. This procedure is done by a cardiologist, who passes a small balloon through a large vein into the heart.

Historically, several surgical interventions are applied to this disease. In 1959, Dr. Senning invented the new technique of atrial level switching (Fig. 3).

In 1963, Dr. Mustard invented a surgery similar to Dr. Senning’s, using a patch to reroute inside the atrium. After these surgeries, the babies are no longer blue or cyanotic. After this surgery, most patients fared well for a period of time. However, some patients developed severe heart failure (heart pumping ability problems) or severe arrhythmia (a heart beating/rhythm problem). This disappointing result was prominent in the presence of a ventricular septal defect.

In 1975, Dr. Jatene succeeded with the first arterial switch operation for transposition. This surgery has two components. One involves the switching of the great arteries, followed by moving the coronary arteries. Switching the great arteries means swapping the aorta and the pulmonary artery (Fig. 4). The coronary arteries are the blood vessels which bring the blood to the heart itself. In a neonate, the great arteries are sized 1 to 1.5 centimeters in diameter. However, the coronary arteries are only 1 to 2 millimeters in diameter. At the time of surgery, these coronary arteries are removed from the aorta with a cuff of tissue of 5 to 7 millimeters. Then this cuff will be anastomosed to the original pulmonary artery. Additional anomalies of ventricular septal defects, atrial septal defects and arch anomalies are repaired as part of the operation.

Risk factors for an arterial switch operation involve coronary anomalies, including a single coronary, intramural coronary and unusual coronary patterns. In the presence of certain cardiac anomalies, such as pulmonary valve stenosis or left ventricular outflow tract obstruction, an arterial switch operation is not chosen as the treatment for transposition.

When the patient has a large ventricular septal defect with pulmonary valve stenosis, a Rastelli type surgery is instituted. A Rastelli type of surgery is composed of ventricular septal defect closure, and rerouting of the left ventricle to the original aortic valve, and placement of a conduit (or tube) between the right ventricle and the pulmonary artery (Fig. 5, 6). This type of surgery has several deficits. First, the patient will require conduit replacement periodically, secondary to obstruction over time. Secondly, in the presence of small ventricular septal defect, the patient may develop left ventricular outflow tract obstruction, which may necessitate further surgical interventions, as well.

Treatment Results
In the majority of cardiovascular centers, the surgical mortality of arterial switch operation is less than 5 percent. The patients with the above mentioned risk factors have a higher mortality rate after arterial switch operations.
Since the left ventricle is used as a systemic ventricle, after arterial switch operations children usually have normal ventricular functions and no heart rhythm abnormalities.
However, late morbidities include neo aortic valve insufficiency, left ventricular outflow tract obstruction and coronary insufficiency.

Spotlight on Jim Bodtke, RDCS

Cardiac Sonographer, Arkansas Children's Hospital

What is your role at ACH and how long have you worked here?
My role at ACH is to provide cardiac echos for our physicians. I started here part time in 2002, and became full time soon after.

Why is your job rewarding?
The rewards for me here at ACH come from many different avenues. They range greatly, from experiencing the grasp of a child’s hand, to a hug for a job well done, to just being a witness to the love that is freely given by the staff here at ACH.

How did you become interested in pediatric cardiology or cardiovascular surgery?
I used to work in an adult lab, but rarely felt that I was making a great impact on a patient’s outcome, nor did it offer me the variety that pediatrics could. I became exposed to pediatric cardiology at another institution and immediately knew what I wanted to do each day.

What do you want people to know about the Heart Center at Arkansas Children's Hospital?
I would want them to know all the people that are part of the Heart Center are here for one reason only: Not out of the need for a job, but because they share a common bond, and that is the children that come here for care, and that they give that care unselfishly.

What do you enjoy most about working with children?
That’s the easiest question to answer: Making them smile. If you can achieve getting a pediatric patient to flash you a smile, even briefly, you know you have made a difference in their day. Besides, for me, that is the easiest part, as well. I stay pretty much on a child’s level most of the time.

What has been your most memorable moment working in the Heart Center at Arkansas Children's Hospital?
The first time I saw a patient without much chance at survival make a full recovery after receiving a heart transplant. This was the first time that I felt I was part of something bigger than myself, or even all of us together. Along with that came the realization that as long as I remain here, I will get to witness this over and over again.

What is your greatest professional achievement?
Sitting in a lab in Leuven, Belgium, with their world-renowned researchers and realizing that the research that we are doing at ACH is on par with theirs. Little Rock, Arkansas – who would have thought?

Jim Bodtke has been instrumental in setting up a new research study in the Heart Station. His study evaluated strain/strain rate analysis of the left ventricular myocardium of transplant patients, as an early indicator of cardiac transplant rejection. Strain/strain rates allow the cardiologist to study the deformation of the heart in a process over time. Strain and strain rate is a new technology in echocardiography that has had very limited pediatric study.

Bodtke enrolled 46 patients within his study and has examined these results collectively with several cardiologists in the ACH Heart Station. In addition to Bodtke’s study, several cardiologists have also begun studies utilizing this data and its significance to cardiac transplant rejection. Jim has been dedicated to achieving our long-term goals of excellence in pediatric echocardiography research.

Sherrie Loyd
Director, Ambulatory Cardiac Services
Cardiology Clinic, Heart Station
Cardiac Cath Lab/Electrophysiology Lab
Arkansas Children’s Hospital