2) Signs/symptoms/clinical findings (Table 109-1)

    a) Omphalocele

  i) Depending upon the size of defect, extruded viscera may include small or large bowel, stomach, spleen, or liver.

  ii) The herniated viscera are covered with a membranous sac composed of fused layers of the amnion and peritoneum, and the bowel is usually morphologically and functionally normal.

  iii) Omphaloceles have a high association with other anomalies.

(1) Chromosomal anomalies

(2) Congenital heart disease

(3) Pulmonary hypoplasia

(4) Genitourinary anomalies

(5) Neural tube defects

(6) Beckwith-Wiedemann syndrome

(7) Pentalogy of Cantrell

    b) Gastroschisis

  i) The herniated viscera and intestines are not covered and are exposed to amniotic fluid and then air at time of delivery leading to inflammation, edema, and functionally abnormal bowel.

  ii) Animal models suggest that amniotic fluid is directly toxic to exposed bowel and may lead to thickened peel and dysmotility (1).

  iii) Although there are less associated anomalies with gastroschisis, nearly 25% of cases have associated gastrointestinal problems including atresia, volvulus, stenosis, and compromised bowel function (2).

  iv) Intrauterine growth retardation is noted in a significant number of gastroschisis cases (3).

1) Surgical treatment

    a) Primary or complete surgical reduction is carried out if the abdomen is large enough to accommodate return of viscera without excessive intra-abdominal pressure that may compromise organ perfusion and decrease ventilatory reserve.

    b) Staged reduction involves covering viscera with prosthetic Silon pouch and gradually reducing the size of the pouch in stages allowing for the abdominal cavity to accommodate to the increased mass over 1 to 2 weeks (4).

4) Anesthetic management

    a) Preoperative considerations

  i) Management of these lesions from birth until surgical repair is directed at minimizing heat and fluid loss from exposed surfaces, normalizing intravascular fluid status, and preventing development of sepsis and hypothermia.

  ii) Cover mucosal surfaces with sterile, saline-soaked dressing; plastic wrap further decreases evaporative losses.

  iii) Nasogastric tube placement helps to prevent intestinal distention.

  iv) Assessment of intravascular fluid status.

  v) Empiric antibiotics are administered given high risk of infection from peritonitis, ischemia and parenchymal disease.

  vi) Identification of associated anomalies (e.g., cardiac, chromosomal, Beckwith-Wiedemann) (4).

    b) Monitors/lines

  i) Standard ASA monitors

  ii) Additional pulse oximeters recommended for upper and lower extremities as lower extremity perfusion may be compromised after closure.

  iii) Arterial line recommended for hemodynamic monitoring and blood gases to gauge effects of abdominal pressure on ventilation.

  iv) Central venous line recommended for additional access and/or postoperative parenteral nutrition.

    c) Intraoperative management

  i) Induction

(1) Orogastric tube should be placed prior to induction to empty stomach contents.

(2) Decision of method of induction should be determined based on clinical condition of patient including factors such as airway, degree of obstruction, and hemodynamic stability.

(3) Choose an endotracheal tube (ETT) size that will allow for ventilation with higher peak inspiratory pressures that may be required after closure.

(4) Consider using a cuffed ETT.

  ii) Maintenance

(1) Avoid nitrous oxide.

(2) Anesthetic with vapor versus TIVA versus balanced techniques depend on clinical situation and availability of access.

(3) Muscle relaxation is highly advised and may be requested by surgeon to facilitate closure.

  iii) Special anesthetic considerations

(1) Higher peak inspiratory pressures may be required to maintain minute ventilation after closure.

(2) Use of PEEP may help minimize atelectasis after closure.

(3) Communicate with surgeons regarding neuromuscular blockade in order to evaluate intra-abdominal pressures (5).

(4) Assessment of intra-abdominal pressure; if <20 mm Hg, primary closure is likely possible.

(5) Consider using peak inspiratory pressure or transduction of intragastric or bladder pressures as diagnostic adjuncts (4).

  iv) Emergence

(1) Except for the most benign small-volume herniations, most patients will require postoperative ventilatory support and NICU care.

(2) Many may require continued paralysis to minimize intra-abdominal pressure.

    d) Postoperative management

  i) Perioperative risks include respiratory failure, ARDS, abdominal compartment syndrome, renal failure, infection, coagulopathy, and hypothermia (5).

  ii) Necrotizing enterocolitis has been reported to complicate the postoperative course of up to 20% of neonates with gastroschisis (6).

  iii) Patients with prolonged ileus may require parenteral nutrition.

  iv) Pain control may be achieved with epidural analgesia via caudal, lumbar, or thoracic approaches with radiographic confirmation (5).

  v) Outcomes in gastroschisis have improved over past few decades with contemporary overall survival rate as high as 90% to 95% (3).

References

1. Vargun R, Aktug T, Heper A, et al. Effects of intrauterine treatment on interstitial cells of Cajal in gastroschisis. J Pediatr Surg 2007; 42:783–787.

2. Sadler T. Langman’s Medical Embryology. 9th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2003.

3. Islam S. Clinical care outcomes in abdominal wall defects. Curr Opin Pediatr 2008;20:305–310.

4. Coté CJ, Lerman J, Todres ID. A Practice of Anesthesia for Infants and Children. 4th ed. : Saunders; Philadelphia, PA 2009:763–764.

5. Holzman RS, Mancuso TJ, Polaner DM. A Practical Approach to Pediatric Anesthesia. Philadelphia, PA: Lippincott Williams & Wilkins; 2008:295–298.

6. Dierdorf SF, Krishna G. Anesthetic management of neonatal surgical emergencies. Anesth Analg 1981;60:204–213.

Intussusception

Nicholette Kasman, MD

1) Pathophysiology

    a) Intussusception occurs when a more proximal portion of bowel invaginates into more distal bowel (1,2).

    b) 90% of pediatric intussusceptions are ileocolic and idiopathic (1).

    c) The most commonly associated diseases are cystic fibrosis, Henoch-Schönlein purpura, and Meckel’s diverticulum (1).

    d) Lymphoid hyperplasia, possibly induced by a viral infection, also can act as a “lead point” in the pathogenesis of intussusception. During this process, the intestine propagates itself distally and with it draws the blood vessels (1).

    e) Initially, compression of the vessels causes venous congestion and bowel edema; however as the obstruction progresses, the arterial supply may become compromised leading to ischemia, bowel necrosis, and gangrene.

2) Signs/symptoms/clinical findings

    a) The classic presentation of intussusception includes (1,3)

  i) Colicky abdominal pain

  ii) “Red currant jelly” stools

  iii) Vomiting

    b) Neonates with acquired lesions rarely present with all symptoms.

    c) Other symptoms include abdominal distension, a palpable abdominal mass, late passage of meconium, lethargy, hypotonia, and fluctuating consciousness (1–3).

    d) Associated findings may include aspiration pneumonia, dehydration, hypovolemia, and metabolic abnormalities.

1) Treatment

    a) The preferred method for reduction of intussusception is radiologic reduction by either barium or air enema.

    b) These procedures have 70% and 84% success rates, respectively (1).

    c) Absolute contraindications to radiologic reduction include peritonitis, perforation, and profound shock.

    d) Recurrence after a radiologic reduction ranges between 10% and 15% (1).

    e) If the intussusception requires surgery, the preferred method is via a laparoscopic repair followed by an open repair.

    f) Recurrence after surgical reduction is unusual occurring in 1% to 3% of cases (1).

4) Anesthetic management

    a) Preoperative considerations

  i) Evaluation of fluid status

(1) Hypovolemia secondary to vomiting may cause an initial contraction alkalosis followed by a metabolic acidosis (4).

(2) Distributive or relative hypovolemia may occur from sepsis due to infection or ischemic bowel.

(3) Baseline electrolytes should be obtained; however, there may not be time to wait to correct abnormalities prior to surgery.

  ii) Anemia may be present secondary to intra-abdominal bleeding. Type and cross should be sent.

  iii) Full stomach precautions should be taken. The patient may benefit from placement of a preoperative nasogastric or orogastric tube.

    b) Monitors/lines

  i) Standard ASA monitors may be adequate in patients who have been medically optimized.

  ii) A preoperatively placed IV may be adequate for access unless patient is hemodynamically unstable or septic.

  iii) In hemodynamically unstable patients, an additional IV, an arterial line, and possibly a central venous line for evaluation of fluid status may be necessary.

    c) Intraoperative management

  i) Induction

(1) Surgical correction of intussusception requires a general anesthetic.

(2) Children may be actively vomiting and are at high risk of aspiration. It is recommended to empty the child’s stomach with a nasogastric or orogastric tube prior to induction with the patient awake to decrease the risk of aspiration on induction.

(3) Induction should then proceed with a rapid sequence induction. All of the concurrent risks of rapid sequence induction in children need to be considered.

(4) Agents

   (a) Induction

     (i) Ketamine, etomidate, propofol, or other agent at the anesthesiologist’s discretion depending on patient stability.

   (b) Muscle relaxants

     (i) The use of succinylcholine or high-dose rocuronium for rapid sequence induction in children is appropriate and indicated in acute bowel obstruction.

   (c) Narcotics

     (i) Midazolam may be considered for preoperative sedation.

     (ii) Fentanyl, morphine, or hydromorphone for analgesia.

   (d) Inhaled agents

     (i) Mask induction is contraindicated as a first choice, but if IV access is lost or not available, it may be considered with concurrent cricoid pressure and suctioning immediately available.

  ii) Maintenance

(1) Choice of drugs for maintenance of anesthesia depends on the clinical situation.

(2) If the patient is too hemodynamically unstable to tolerate enough inhalational agent, a ketamine infusion (0.5 to 2 mg/kg/h IV) may provide adequate anesthesia without depressing blood pressure (5,6).

(3) There is conflicting evidence about the occurrence and significance of bowel distension after application of N₂O. Many surgeons prefer that it be avoided due to concerns about clinically significant bowel distension that would impair the working space (4).

  iii) Special anesthetic considerations

(1) In severe cases, there may be significant fluid losses from evaporation during open procedures and through third spacing (1,4).

(2) Gangrenous bowel may result in severe metabolic acidosis and require correction of electrolyte abnormalities.

(3) Vigilance must be maintained for developing sepsis.

(4) Blood product transfusion may be indicated with bleeding and/or fluid shifts.

  iv) Emergence

(1) The decision whether to proceed with extubation should be based on the stability of the patient as determined by the anesthesiologist.

    d) Postoperative management/analgesia

  i) There is a risk of persistent postoperative ileus, venous thrombosis, infection, and abdominal compartment syndrome.

  ii) If the repair was done laparoscopically, systemic analgesics combined with injections of local anesthetic at the trochar sites may be sufficient for postoperative pain control (7).

  iii) If the repair was done as an open procedure, placement of a postoperative epidural or single-shot caudal may assist patient recovery.

  iv) If there is significant edema or third spacing, the surgeon may not be able to close the abdomen. Postoperative mechanical ventilation in a pediatric intensive care unit may be necessary.

References

1. Waseem M, Rosenberg HK. Intussusception. Pediatr Emerg Care 2008;24(11):793–800.

2. Kleizen KJ, Hunck A, Wijnen MH, et al. Neurological symptoms in children with intussusception. Acta Paediatr 2009;98(11):1822–1824.

3. Bhowmick K, Kang G, Bose A, et al. Retrospective surveillance for intussusception in children aged less than five years in a South Indian tertiary-care hospital. J Health Popul Nutr 2009;2(5):660–665.

4. Roberts J, Romanelli T, Todres I. Neonatal emergencies. In: Cote, Lerman, Todres, eds. A Practice of Anesthesia for Infants and Children. 4th ed. Chap 36: 760–766.

5. Stowe DF, Bosnjak ZJ, Kampine JP. Comparison of etomidate, ketamine, midazolam, propofol, and thiopental on function and metabolism of isolated hearts. Anesth Analg 1992;74(4):547–558.

6. Zausig YA, Busse H, Lunz D, et al. Cardiac effects of induction agents in the septic rat heart. Crit Care 2009;13(5):R144.

7. Lonnqvist P, Lerman J. General abdominal and urologic surgery. In: Cote, Lerman, Todres, eds. A practice of Anesthesia for Infants and Children. 4th ed. Chap 27: 583–594.

Hypertrophic Pyloric Stenosis

Calvin Kuan, MD

1) Pathophysiology

    a) Gradual hypertrophy of muscularis layer of pylorus resulting in progressive gastric outlet obstruction.

    b) Persistent vomiting leads to loss of fluids and electrolytes (e.g., hydrochloric acid from stomach), resulting in classic hypovolemia with hypochloremic, hypokalemic metabolic alkalosis.

    c) Increased aldosterone induces a renal response to hold on to sodium and hydrogen by secreting potassium instead, normalizing serum pH initially.

    d) Upon depletion of electrolytes (e.g., total body potassium), kidneys secrete hydrogen (paradoxic aciduria), further increasing metabolic alkalemia.

    e) Continued emesis can result in prerenal azotemia, hypovolemic shock, and metabolic acidosis.

2) Signs/symptoms/clinical findings

    a) Early

  i) Nonbilious emesis after feeding, with infant still hungry afterwards.

  ii) Persistent episodic projectile vomiting develops in 70% of patients.

    b) Later: evidence of hypovolemia

  i) Tachycardia

  ii) Decreased urine output

  iii) Poor skin turgor

  iv) Decreased activity

    c) Much later: severe dehydration

  i) Weight loss

  ii) Altered mental status

  iii) Shock

1) Diagnosis

    a) Clinical

  i) History of emesis as described above.

  ii) Palpation of “olive-shaped mass” in right upper quadrant near the midline in the abdomen.

  iii) Infants are usually diagnosed earlier now than in the past, so many will not present with signs of severe dehydration or electrolyte abnormalities.

    b) Radiographic

  i) The modality of choice is abdominal ultrasound.

  ii) Upper GI barium swallow is performed when the ultrasound is nondiagnostic.

4) Surgical treatment

    a) Surgical myotomy (open vs. laparoscopic) with typical surgical time 0.5 to 1 hour without significant blood loss or fluid shifts.

    b) This is not a surgical emergency—intravascular volume and metabolic stabilization and correction are first priorities prior to surgical repair.

5) Anesthetic management

    a) Preoperative considerations

  i) Clinical evaluation of hydration status

(1) Adequate urine output of at least 0.5 cc/kg/h.

(2) Normal skin turgor, skin color, and capillary refill time.

(3) Normal tear production and moist mucus membranes.

(4) Normal mental status and activity level.

  ii) Laboratory evaluation

(1) Goal of plasma chloride > 100 mEq/L.

(2) Goal of plasma bicarbonate < 29 mEq/L.

(3) Goal of urine chloride > 20 mEq/L.

(4) Treatment of hypokalemia should be initiated only after alkalemia resolved and urine output verified.

    b) Monitors/lines

1) Standard ASA monitors

2) Single functioning peripheral IV should be in situ preoperatively.

1) Invasive monitoring (arterial or central venous) is not usually necessary.

    c) Intraoperative management

  i) Induction

(1) Prior to induction, perform awake orogastric suctioning in supine and left and right lateral positions with large-bore orogastric tube (OG) to minimize the risk of aspiration.

(2) Preoxygenate with 100% O₂.

(3) Awake intubation may be performed if there is a concern for a difficult airway.

(4) Rapid sequence induction with cricoid pressure

   (a) Succinylcholine ± atropine OR

   (b) Rocuronium

(5) Replace OG tube following intubation.

  ii) Maintenance

(1) Inhalational agent or TIVA with propofol or balanced technique.

(2) Minimize opiates given risk of post-op apnea in minimally painful laparoscopic cases.

  iii) Special anesthetic considerations

(1) Aspiration risk is high due to nature of disease despite appropriate fasting time, so gastric suctioning in many positions is advised before induction.

(2) Surgical time may be very short with either open or laparoscopic procedures, so timing of muscle relaxants and analgesics with emergence must be considered.

  iv) Emergence

(1) Awake extubation is recommended.

(2) Full reversal of nondepolarizing blockade is recommended.

    d) Postoperative management

  i) Analgesia

     (i) Local anesthetics may be infiltrated by the surgeon into wound.

     (ii) Acetaminophen may be given rectally preoperatively or postoperatively.

     (iii) Opioids may be necessary with open procedures; however, the patient (especially ex-premature infants) should be monitored for post-op apnea.

  ii) Disposition

(1) Patients should not be discharged home immediately postoperatively.

(2) Patients should be monitored for apnea for at least 12 hours following surgery due to abnormal CO₂ response caused by the preoperative metabolic alkalosis (1).

Reference

1.Coté CJ, Lerman J, Todres ID. A Practice of Anesthesia for Infants and Children. 4th ed. Philadelphia, PA: WB Saunders; 2009.

Suggested Reading

2. Holzman RS, Mancuso TJ, Polaner DM. A Practical Approach to Pediatric Anesthesia. Philadelphia, PA: Lippincott Williams & Wilkins; 2008.

Congenital Heart Disease

Calvin Kuan, MD

1) Introduction

    a) To safely manage patients with congenital heart lesions, the anesthesiologist must thoroughly understand:

  i) The individual patient’s anatomy (visualizing the path of blood flow throughout the body including any abnormal pathways and shunts).

  ii) How the lesion(s) affects the patient’s physiology.

  iii) Be able to predict the interactions of surgery and anesthesia—including pain, blood loss, fluid management, positive pressure ventilation, as well as the effects of oxygen and anesthetic agents.

    b) It is strongly recommended that children with CHD be treated at institutions with experienced multidisciplinary teams, and that there is adequate communication between all the services involved—primary care physician, pediatric cardiologist, neonatologist, pediatric intensivist, surgeon, anesthesiologist, and any relevant subspecialist.

2) Risks of anesthesia

    a) Children, particularly neonates and infants, with major cardiac anomalies have significantly increased risk of both cardiac arrest and mortality for noncardiac surgeries (1–4).

  i) Children with CHD are more likely to have cardiac arrest compared to children without CHD.

  ii) In one study, 54% of cardiac arrests in children with CHD occurred in the general operating rooms for noncardiac surgeries (4).

  iii) Outcomes appear significantly better for the patient with CHD when cared for by teams with experience managing such patients (3).

    b) With rare exceptions, patients with the following lesions are at low risk and do not require special care.

  i) repaired patent ductus arteriosus (PDA)

  ii) repaired or unrepaired secundum atrial septal defect (ASD)

  iii) repaired or unrepaired asymptomatic, small ventricular septal defects (VSD)

  iv) asymptomatic pulmonary stenosis (PS)

    c) Patients with the following lesions are at highest risk and should be treated at a comprehensive pediatric cardiac center:

  i) Any patient with single ventricle physiology

(1) Hypoplastic left heart syndrome (HLHS)

(2) Tricuspid atresia

(3) Double outlet right ventricle (DORV)

(4) Unbalanced atrioventricular canal (AVC)

(5) Double inlet left ventricle (DILV)

(6) Severe Ebstein anomaly

  ii) pulmonary hypertension (PH)

  iii) ventricular dysfunction or heart failure, particularly cardiomyopathies

  iv) moderate-to-severe valvular obstruction or regurgitation (particularly aortic stenosis)

  v) systemic to pulmonary artery surgically placed shunt (BT shunt, central shunt, aortopulmonary window)

  vi) status post recent heart transplantation

    d) Patients with other lesions/conditions fall in between the two categories and should be assessed individually as there is wide range of symptoms with varying pathophysiology.

1) Preoperative evaluation

    a) Know the diagnosis

  i) It is absolutely essential to know the correct cardiac anatomy as each lesion has different implications for anesthetic care.

    b) Get accurate information

  i) It is not uncommon for patients and parents to have an incomplete understanding of a patient’s physiology and complex medical history.

  ii) Accurate information should be obtained directly from the patient’s cardiologist, and from thorough review of medical records and studies.

    c) Past medical/surgical history

  i) Anatomy/physiology: Understanding the natural history of the individual lesions is essential. For example:

(1) A child with a lesion that depends on a PDA to deliver blood may deteriorate when the duct closes a few days after birth.

(2) A child with a large VSD may be minimally symptomatic at 1 year old but develop Eisenmenger physiology at 20 years of age.

  ii) Surgical history. The anatomy and physiology may change significantly with each surgical procedure. For example:

(1) A child with a history of a Blalock Taussig shunt may have inaccurate blood pressure readings on the ipsilateral arm.

(2) A child who has had a heart transplant may not respond to atropine given for bradycardia and may require epinephrine instead.

  iii) Past medical history/review of systems: Review the patient’s past medical history and how illnesses of other organ systems may affect the anesthetic management. For example:

(1) A child with severe aortic stenosis may not tolerate the tachycardia caused by albuterol given to treat bronchospasm.

(2) A child with heterotaxy/asplenia should be treated as being relatively immunocompromised.

    d) Physical exam

  i) Vital signs: Know the normal values at rest for the individual patient with the particular lesion. For example:

(1) A patient on β-adrenergic blockade should be expected to have a slower-than-normal heart rate.

(2) A teenager with an unrepaired coarctation of aorta may be expected to have baseline hypertension.

  ii) Oxygen saturation: It is essential to know what the oxygen saturation measurement should be for each patient whether cyanotic or acyanotic, and to know whether the patient has an O₂ requirement at rest to maintain the saturation. For example:

(1) A neonate with an unrepaired hypoplastic left heart syndrome (HLHS) may have baseline saturations of 75% to 85%, which is optimal. Saturations of 95% may actually be too high and indicate pathologic pulmonary overcirculation.

(2) A child with pulmonary hypertension who requires an FiO₂ of 40% at baseline should be induced with an FiO₂ of at least 40% to avoid the risk of an increase in pulmonary vascular resistance due to hypoxia.

  iii) Cardiovascular/fluid/volume status: It is important to evaluate the fluid status of children with heart disease as they may not tolerate relative hypovolemia especially under anesthesia. For example:

(1) The patient’s blood pressure may be in the normal range when awake, but administration of anesthetic agents may lower systemic vascular resistance (e.g., inhaled agents, propofol) and result in hypotension.

(2) Children with systemic to pulmonary artery shunts are at an increased risk of clotting the shunt off when hypovolemic.

  iv) Exercise tolerance: When one does not have documented recent echocardiography exams or cardiac catheterizations, the subjective reporting of exercise ability is a useful assessment tool of cardiac function. Recent changes should raise the concern for deterioration in cardiac function. Examples of questions for parents or patients are:

(1) “Does the child do physical exercise at school? If so, what sort of activities or sports can she do?”

(2) “Can the child run, jump, and play? And can he keep up with other children his age?”

(3) “How long can she play before she gets tired, short of breath, or turn blue?”

(4) “Has the child’s ability to do any of the above changed noticeably recently?”

  v) Recent changes should raise the concern for deterioration in cardiac function and should prompt additional investigation prior to anesthesia and surgery.

    e) Studies

  i) Electrocardiogram

(1) All children with a history of cardiac disease should have a baseline EKG done as close to anesthetic date as possible.

(2) Having a baseline to compare with intraoperative changes may avoid unnecessary interventions.

  ii) Echocardiography exam

(1) Except for children who have had a complete repair of their lesions, are asymptomatic, and have regular follow-up with their cardiologist, a recent echocardiogram (within 3 to 6 months) by the child’s pediatric cardiologist is recommended.

(2) Decision whether to proceed with anesthesia without a recent exam should be made on an individual basis depending on the changes in cardiac physiology expected since the last exam and the information that would be gained.

  iii) Cardiac catheterization findings

(1) Cardiac catheterization is not required for all patients.

(2) Severity of pulmonary hypertension (PH) affects perioperative outcomes and a more recent cardiac catheterization may be required if the patient is known to have significant PH.

(3) If the patient has had a catheterization, useful information may be available:

   (a) Measuring gradients across valves or shunts

   (b) Measuring systolic and diastolic pressures that may indicate degree of ventricular function or failure

   (c) Identifying stenoses not seen on echocardiogram

   (d) Identifying occluded vessels that might be chosen for venous or arterial access.

   (e) Evaluating anatomy and patency of coronary arteries

   (f) Measuring the Qp:Qs (ratio of pulmonary to systemic blood flow), which may give information on the hemodynamic effects of O₂.

     (i) Qp/Qs < 1: indicates right left shunt and cyanosis.

     (ii) Qp/Qs = 1: indicates no shunt, or balanced shunt. Usually asymptomatic.

     (iii) Qp/Qs > 1: indicates left-to-right shunt, with pulmonary overcirculation and potential congestive heart failure CHF.

    f) Labs

  i) CBC (complete blood count)

(1) Know the goal hemoglobin/hematocrit (Hgb/Hct) for the patient.

   (a) Some children may require much higher than normal baseline Hct. For example, cyanotic children in general have a high Hct to increase O₂ content of blood.

   (b) Our institutional practice is to keep the Hgb ≥ 15 g/dL (Hct > 45% to 50%) for cyanotic children in the perioperative period to optimize O₂-carrying capacity.

(2) Baseline platelet count

   (a) Patients on long-term aspirin therapy may have decreased platelet function despite normal platelet counts.

   (b) Patients on left ventricular assist devices are often placed on antiplatelet medications, so thrombocytopenia and abnormal platelet function should be anticipated.

  ii) Type and cross

(1) Patients who have had multiple surgeries and transfusions may develop antibodies to blood products. Additional time may be required for the blood bank to crossmatch blood.

  iii) Chemistries

(1) Potassium

   (a) Hyperkalemia is a much greater concern and risk of morbidity than hypokalemia in the pediatric population.

   (b) An exception to the above recommendation is that patients on digoxin should have K + ≥ 3.5. Digoxin competes with K + in the myocardium; hypokalemia increases risk of digoxin toxicity.

   (c) Consider using washed RBC or freshest RBC if large-volume transfusion is anticipated.

(2) Calcium

   (a) Children, particularly neonates, are dependent on calcium for myocardial function and do not tolerate hypocalcemia.

   (b) Patients with DiGeorge syndrome may have relative hypocalcemia and require additional supplementation.

   (c) Administration of blood products or albumin may cause hypocalcemia.

  iv) Coagulation studies

(1) Patients may be anticoagulated for prosthetic valves or a history of thromboses. Negotiation may be necessary between a surgeon who wants to do a craniotomy and a cardiologist who wants to prevent clots on the aortic or the mitral valve.

4)Special anesthetic considerations

    a) “A bubble is a bullet to the brain/heart:” It is absolutely critical to ensure that all fluids entering the patient are cleared of air bubbles that may embolize to the brain or the coronary arteries.

    b) “Oxygen is a drug:” O₂ causes pulmonary vascular vasodilation.

  i) For a patient with pulmonary hypertension, it may be beneficial in lowering pulmonary vascular resistance.

  ii) For a child with single ventricle physiology whose cardiac output depends on a balance between systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR), even a slight increase in FiO₂ may cause a decrease in PVR and result in systemic hypoperfusion and myocardial ischemia.

    c) Postoperative care/disposition

  i) Patients should be closely monitored postoperatively by PACU personnel experienced with taking care of patients with CHD.

  ii) Patients who are young, unrepaired, cyanotic, or have single ventricle physiology might require monitoring overnight depending on the surgical procedure.

  iii) Special care should be taken when administering narcotics due to effects on respiratory drive, oxygenation and ventilation, and their effects on cardiac physiology.

    d) Vascular access

  i) Vascular access (venous and arterial) may be extremely difficult in patients who have undergone several major surgeries, or have been hospitalized for a long time.

  ii) It is not uncommon for vessels to be stenotic or occluded and therefore unusable.

  iii) Some patients may require very specific placement of lines. For example, the patient with a coarctation will require an arterial line in the right arm.

5) Selected lesions and anesthetic concerns The purpose of this section is to provide some basic understanding of select congenital cardiac lesions. Please refer to recommended references for additional information.

Anesthetic Considerations for Selected Congenital Lesions

Atrial Septal Defect (Fig. 112-1)

Ventricular Septal Defect (Fig. 112-2)

Coarctation of Aorta (Fig. 112-3)

Tetralogy of Fallot (Fig. 112-4)

Glossary of Congenital Heart Disease Terms

Aorto-pulmonary window (aka APW or aortopulmonary septal defect): May be a pathological congenital lesion or a surgical procedure performed to increase pulmonary blood flow resulting in side-to-side connection of ascending aorta to main pulmonary artery. Physiologically similar to central shunt.

Arterial switch procedure (aka Jatene procedure):Surgical procedure to repair D-TGA (see entry below and Fig. 112-5) by switching malpositioned aorta and pulmonary artery. Requires moving the coronary arteries to new location (Fig. 112-6).

Blalock-Taussig shunt (BTS): Surgical procedure that creates a shunt between the subclavian artery and the pulmonary artery to supply additional pulmonary blood flow in some congenital lesions.

Classic BTS: End to side anastomosis of native subclavian artery to ipsilateral pulmonary artery.

Modified BTS: Artificial shunt placed side to side between the subclavian artery and the ipsilateral pulmonary artery.

Central shunt: Artificial shunt placed side to side between ascending aorta and the main pulmonary artery to increase pulmonary blood flow. Physiologically similar to aortopulmonary window.

Complete transposition of the great arteries (aka D-TGA): Congenital lesion where aorta arises from right ventricle and pulmonary artery arises from left ventricle resulting in two parallel circulations. Survival depends on adequate mixing of oxygenated and deoxygenated blood. (Fig. 112.5).

Damus-Kaye-Stansel (DKS): Surgical procedure used for various congenital lesions with systemic outflow tract hypoplasia or obstruction. Main pulmonary artery is transected and connected end to side to ascending aorta to allow blood to go systemically. An alternative source of pulmonary blood flow is created (see entries for BT shunt, Sano, or RV to PA conduit).

Double outlet right ventricle (DORV): Congenital lesion where both the aorta and the pulmonary artery arise from the right ventricle. A VSD is present for exit of blood from left ventricle. Pathophysiology depends on position of VSD and other factors. May result in single or dual ventricle physiology.

Double switch procedure: Surgical procedure to repair L-TGA (see entry below, and Fig. 112-7) with an atrial level switch (see entries for Mustard or Senning) and arterial switch procedure. Usually requires preconditioning with pulmonary artery banding (PAB).

Ebstein anomaly:“Atrialization” of the right ventricle. Abnormal and downward displacement of tricuspid valve with spectrum of clinical manifestations from asymptomatic to single ventricle pathway. Often associated with dysrhythmias.

Endocardial cushion defect (ECD aka AV canal, aka atrioventricular septal defect (AVSD)): Congenital lesion with a spectrum of manifestations including primum ASD, inlet VSD, and mitral and tricuspid valve abnormalities. Often associated with Trisomy 21.

Fontan procedure: Surgical procedure that is the final stage of palliation for single ventricle lesions usually done at 12 to 24 months of age. The goal of this procedure is to direct all venous return (now the IVC, in addition to the SVC return that was already redirected during the Glenn procedure) to the pulmonary circulation, bypassing the heart completely, depending on passive drainage into pulmonary arteries. After this surgery, the patient will ideally have 100% SpO₂.

Original Fontan: End-to-end connection of SVC to right pulmonary artery, separation of right and left pulmonary arteries at confluence, anastamosis of right atrial appendage to the proximal separated end of right pulmonary artery RPA, closure of ASD, and ligation of main pulmonary artery. Not performed any longer.

Extracardiac Fontan: Use of Dacron tube conduit to connect the IVC to the RPA. Has fewer complications from dysrhythmias.

Lateral tunnel Fontan (aka intracardiac): Use of the patient’s native right atrial tissue to create a tunnel connecting the IVC to the PA, without any blood flow to right ventricle. Associated with higher risk of dysrhythmias.

Glenn procedure (aka cavopulmonary shunt): In patients with single ventricle physiology, a surgical procedure that connects the SVC to the pulmonary artery allowing venous drainage from upper body to bypass the heart. Usually done to volume unload the heart and to increase pulmonary blood flow.

Classic Glenn: In the original surgery, the right pulmonary artery was transected and anastamosed end to end to the SVC. The left pulmonary artery (now discontinuous from the right) continued to get flow from heart via main pulmonary artery.

Bidirectional Glenn. The current modification connects the SVC to the right PA, but allows venous blood to drain both to right and left pulmonary arteries, hence “bidirectional.”

Bilateral bidirectional Glenn. For patients with right and left SVCs, both SVCs must be connected to ipsilateral pulmonary arteries, hence “bilateral” shunts.

Jatene procedure—see Arterial switch procedure.

Levotransposition of the great arteries (aka L-TGA or congenitally corrected TGA [cc-TGA]): Congenital lesion of ventricular inversion where the right-sided ventricle (that pumps to the pulmonary artery) is morphologically a left ventricle, and the left-sided ventricle (that pumps to the aorta) is morphologically a right ventricle. Functionally normal anatomy, but often associated with dysrhythmias, other cardiac lesions, and potential failure of the systemic ventricle (Fig. 112-7).

Mustard procedure: Surgical procedure using pericardial or artificial material to create a baffle (i.e., rerouting of blood flow) in the atria to palliate D-TGA. Similar to Senning procedure (Fig. 112-8).

Norwood procedure: First-stage surgical procedure in the pathway to palliate hypoplastic left heart syndrome. Repair includes creation of neoaorta using native main pulmonary artery that is transected. Alternative source of pulmonary blood flow is created—for example, Sano RV to PA shunt. Subsequent stages include Glenn and Fontan procedure (Fig. 112-9).

Partial anomalous pulmonary venous return (PAPVR): Congenital lesion where some of the pulmonary veins do not drain into the left atrium, but drain into the right atrium or some other part of the venous system. When none of the pulmonary veins drain normally into the left atrium, the lesion is termed total anomalous pulmonary venous return (TAPVR).

Potts shunt: Surgical procedure creating a shunt between the descending aorta and the left pulmonary artery. No longer performed.

Pulmonary atresia with intact ventricular septum (PA/IVS): Congenital lesion with an atretic pulmonary valve and no VSD for exit of blood from the right ventricle. An atrial shunt (PFO or ASD) is necessary for survival. Coronary sinusoids may develop from the elevated RV pressures, resulting in increased risk of right ventricular ischemia.

Pulmonary artery banding (PAB): Surgical procedure to tighten the pulmonary artery to decrease amount of pulmonary blood flow and/or to strengthen the ventricle.

Rashkind procedure: Procedure performed at bedside or in the cardiac cath lab to enlarge a patent foramen ovale or ASD in lesions that require increased mixing of systemic and pulmonary circulation, e.g., D-TGA with an intact atrial septum.

Rastelli procedure: Surgical procedure used to correct certain lesions with pulmonary artery abnormalities. The pulmonary artery is transected. The VSD is closed with a patch that simultaneously directs blood from the LV to the aorta. Finally, an RV to PA conduit is created to supply pulmonary blood flow.

Sano modification(Fig. 112-9): Surgical procedure creating a valved RV to PA conduit as a modification of the Norwood procedure.

Senning procedure. Surgical procedure using native atrial tissue to create a baffle in the atria to palliate D-TGA. Similar to Mustard procedure.

Tetralogy of Fallot: See TOF entry in chapter above.

Tetralogy of Fallot with absent pulmonary valve (TOF/APV): Congenital lesion that is a small subset of TOF where the pulmonary valve is completely absent resulting in severe pulmonary regurgitation. A pulmonary artery aneurysm may develop that may be so large as to compress the trachea and bronchi, causing severe airway problems.

Tetralogy of Fallot with pulmonary atresia and MAPCAs (major aortopulmonary collateral arteries) (TOF/PA/MAPCA’s): Congenital lesion previously described as truncus arteriosus type IV. An extreme form of TOF with complete pulmonary atresia. Pulmonary blood flow is from PDA or multiple aortopulmonary collateral arteries (MAPCAs). Surgical repair with unifocalization procedure.

Total anomalous pulmonary venous return (TAPVR): None of the pulmonary veins drain into the left atrium. The specific anatomy determines the physiology and the urgency of repair. Obstructed TAPVR is a surgical emergency.

Tricuspid atresia: Congenital lesion with absent or atretic tricuspid valve and hypoplastic right ventricle. Repair of this single ventricle lesion eventually leads to Fontan procedure.

Truncus arteriosus: Congenital lesion where only one great vessel leaves the heart and supplies blood flow to pulmonary arteries, aorta, and coronary arteries. A VSD is necessary for survival. Associated with interrupted aortic arch and DiGeorge syndrome.

Unifocalization procedure: Complex surgical procedure for treatment of patients with TOF/PA/MAPCA’s where aortopulmonary collaterals are separated from the aorta and connected to the pulmonary artery to supply deoxygenated blood to lungs. May be done as single surgery or staged procedure depending on degree of pulmonary hypoplasia.

Waterston shunt: Surgical procedure creating a shunt between the ascending aorta and the right pulmonary artery. No longer performed.

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