Pediatric Cardiovascular Surgery

Katsuhide Maeda MD, PhD¹

V. Mohan Reddy MD¹

Frank L. Hanley MD¹

Claudia Benkwitz MD, PhD²

Komal Kamra MD²

M. Gail Boltz MD²

Chandra Ramamoorthy MD²

¹SURGEONS

²ANESTHESIOLOGISTS

SURGERY FOR ATRIAL SEPTAL DEFECT (OSTIUM SECUNDUM)

SURGICAL CONSIDERATIONS

Description: Atrial septal defects (ASDs) are among the most common congenital cardiac defects. ASDs vary widely in size and location and are broadly classified as ostium secundum, ostium primum, sinus venosus, and coronary sinus types (Fig. 12.4-1). Ostium secundum defects—the most common (80%)—result from an incompletely formed or fenestrated septum primum covering the fossa ovalis. A L → R shunt results in augmented pulmonary blood flow which, if left uncorrected, may → RV failure, atrial arrhythmias, pulmonary HTN, and, rarely, pulmonary vascular occlusive disease (PVOD). In 1953, Gibbon successfully repaired an ASD using a pump-oxygenator and, in doing so, ushered in the era of open cardiac surgery.

Secundum ASDs that fail to close spontaneously should be closed electively in early childhood to avoid long-term complications. Currently, ASD closure is performed through a minimally invasive midline partial sternotomy approach on CPB. A right anterolateral thoracotomy through the 4th intercostal space also provides satisfactory exposure and provides female patients with better cosmesis. After CPB and cardioplegic arrest or ventricular fibrillation have been instituted, a right atriotomy is created, and the ASD is visualized.

Repair is affected by direct suture closure or patch closure, using autologous pericardium or prosthetic material (e.g., Gore-Tex, Dacron). After the repair is completed and the atriotomy is closed, standard de-airing maneuvers are performed, the aortic cross-clamp is released, and CPB is discontinued. The chest is then closed in the standard fashion.

Variant procedure or approaches: Patent foramen ovale (PFO) in adults is becoming a common indication for device closure to avoid risk of paradoxical embolism and stroke during surgery.

Usual preop diagnosis: ASD; ostium secundum defect; other variants

▪ SUMMARY OF PROCEDURE

Position	Supine or lateral decubitus (thoracotomy)
Incision	Minimally invasive midline incision with limited right median sternotomy; right anterolateral thoracotomy (4th intercostal space): Robotic-assisted total endoscopic surgery
Unique considerations	R → L shunt → systemic embolization
Antibiotics	Cefazolin 25 mg/kg q 4 h
Surgical time	Aortic cross-clamp or ventricular fibrillation time: 10-30 min Total: 2 h
Closing considerations	Routine closure with chest tube in pericardial space; temporary atrial pacing wire (older patients); possible left atrial line for monitoring
EBL	Minimal
Postop care	Extubation in OR or within 1st 4 h; 24-h monitoring in ICU
Mortality	Rare
Morbidity	Hemorrhage Postpericardiotomy syndrome Atrial arrhythmias
Pain score	6-8

Figure 12.4-1. Location of ASDs, numbered in decreasing order of frequency: 1 = secundum; 2 = primum; 3 = sinus venosus; 4 = coronary sinus type. IVC = inferior vena cava; PT = pulmonary trunk; RV = right ventricle; SVC = superior vena cava. (Reproduced with permission from the Mayo Foundation for Education and Research.)

▪ PATIENT POPULATION CHARACTERISTICS

Age range	Neonate-adults
Male:Female	1:2
Incidence	10-15% of congenital heart defects
Etiology	Unknown; sometimes associated with syndromes such as Holt-Oram.
Associated conditions	ASD may coexist with nearly any of the other recognized congenital cardiac anomalies but is more commonly associated with pulmonary stenosis (10%), partial anomalous pulmonary venous return (7%), VSD (5%), PDA (3%), and mitral stenosis (2%). ASDs are also part of other malformations, including tricuspid atresia, total anomalous pulmonary venous connection (TAPVC), and mitral atresia.

ANESTHETIC CONSIDERATIONS

PREOPERATIVE

Pathophysiology	Although the septum secundum ASD is the most common one (˜80% of all ASDs), periop management varies little among all types of ASDs (including ostium primum, sinus venosus, and coronary sinus types). One principle guideline in all L → R shunts is the estimation of shunt flow: Q_p:Q_s. The size of the defect and relative compliances of both ventricles are the two main factors determining the degree of shunting at the atrial level and thereby ultimately pulmonary blood flow (Q_p). Patients are generally asymptomatic until the Q_p:Q_s ratio exceeds 3.0. As the shunt flow increases, Sx of pulmonary overcirculation may develop (e.g., feeding difficulties, failure to thrive, tachypnea at rest, frequent URIs, and arrhythmias related to atrial dilatation). L → R shunt ↑ pulmonary blood flow (Q_p) → ↑ PA pressures → ↑ PVR → RV overload → RV failure. The larger the area of the defect, the greater the shunt.
Cardiovascular and respiratory	Most infants with ASDs are asymptomatic. ASDs are detected on cardiac auscultation (fixed splitting of S2) or sometimes during neurological workup for TIAs or strokes secondary to paradoxical emboli. Depending on the degree of shunting (Q_p/Q_s), young children may have h/o frequent URIs. Cyanosis is rare and indicates shunt reversal and development of pulmonary HTN. Although almost 90% of small secundum ASDs close spontaneously in the first year of life, surgical repair is usually recommended between 3 and 5 years of age as these patients are at risk for paradoxical embolism, stroke, bacterial endocarditis, and ultimately CHF. For some patients (depending on age, size, and location of the ASD), endovascular closure in the cath lab, or more recently with hybrid procedures, may be suitable alternatives, with both obviating the need for CPB. Tests: EKG: normal or RVH. CXR: cardiomegaly and ↑ pulmonary vascular markings. ECHO. TEE: essential for locating and estimating size of defect, other valvular abnormalities, and identification of pulmonary vein anatomy. Cardiac CT may be indicated for delineation of the pulmonary veins in sinus venous ASDs because of the association of anomalous pulmonary venous return.
Laboratory	Hb/Hct; T&C
Premedication	Patients > 8 mo old may benefit from midazolam 0.5-0.75 mg/kg po 20 min before induction.

INTRAOPERATIVE

Anesthetic technique: GETA. Most of these patients are candidates for fast-tracking—the practice of extubating cardiac patients in the OR or within 4 h of completion of surgery. To achieve this goal, the anesthetic technique must be adjusted to allow for early extubation.

Criteria for fast-tracking include patients > 4 mo of age, short CPB run, stable hemodynamic profile, minimal inotropic support, normal acid-base status, and adequate surgical hemostasis. Patients who are pacemaker-dependent are not suitable candidates for fast-tracking. Generally, patients selected for fast-tracking have undergone repair of a secundum ASD, VSD (no evidence of postop pulmonary HTN), bidirectional Glenn and Fontan procedures, or a RV → PA conduit change. For patients with a single ventricle, resumption of spontaneous ventilation decreases intrathoracic pressure thereby increasing venous return and improving CO.

Induction	Following inhalation induction using sevoflurane (O₂/N₂O), an iv is placed and intubation facilitated with rocuronium (0.6-1 mg/kg). After ET intubation, an arterial line is placed for close BP monitoring. Fast-track: Inhalation induction (sevoflurane ± N2O) is followed by placement of a PIV. Fentanyl (2-5 mcg/kg) and a muscle relaxant (e.g., rocuronium 0.6-1 mg/kg) are administered, and the airway is secured. Subsequently, an arterial line is placed. For patients who are not candidates for regional anesthesia (e.g., parent preference, spine abnormality, bleeding disorder), intravenous techniques are used (e.g., remifentanil 0.1-0.4 mcg/kg/min). Because most patients have good myocardial function, propofol (100-200 mcg/kg/min) may also be used, often with ketamine (20-50 mcg/kg/min). Propofol may also be used after separation from CPB and in transport to the ICU, usually at a lower dose (25-75 mcg/kg/min), weaned, and discontinued just prior to extubation. Non-fast-track: An inhalation induction with sevoflurane ±N₂O is usually well tolerated. Then, iv access is established and intubation facilitated by muscle relaxant (rocuronium 0.6-1 mg/kg) and supplemental fentanyl. For patients who are not candidates for fast-tracking, the standard anesthetic is fentanyl 20-40 mcg/kg in divided doses with supplemental isoflurane before and during CPB. Additional midazolam (0.1-0.3 mg/kg) may be administered to reduce chance of recall and awareness. An iv induction should be used in patients with significant pulmonary HTN and/or RV failure. iv induction can be accomplished with etomidate 0.1-0.3 mg/kg or ketamine 0.5-1 mg/kg, followed by a muscle relaxant (e.g., rocuronium 1 mg/kg).
Maintenance	For maintenance of anesthesia, inhaled agents, iv agents, regional anesthetic, or a combination may be used. N2O is turned off after induction to avoid expansion of any VAE. In patients with pulmonary HTN, RV failure and/or other medical conditions requiring postop mechanical ventilation, a high-dose narcotic technique may be appropriate (e.g., fentanyl 50-150 mcg/kg ± inhalation agent).
Emergence	If the choice is made to extubate the patient receiving remifentanil in the OR, check level of paralysis and reverse as appropriate; isoflurane is terminated during skin closure, and the remifentanil is turned off last, when the dressing is applied. Extubation is performed once the patient meets standard criteria (e.g., -25 cm H₂O NIF, spontaneous ventilation, adequate sat, hemodynamic stability, none or minimal inotropic support). Because remifentanil has an extremely short half-life, and in the absence of regional anesthetic, it is necessary that a long-acting opioid (e.g., hydromorphone 10-15 mcg/kg) is administered in a timely fashion to ensure postop analgesia. Propofol 25-75 mcg/kg/min ± remifentanil may be used for transport. Extubation is then performed in the ICU. Vasodilators are usually not required for BP control. O₂, bag, mask, airway equipment, and emergency drugs should be available during transport.
Blood and fluid requirements	IV: appropriate for patient’s size × 1-2 LR @ TKO Blood warmer [check mark] for air bubbles T&C 1 U PRBC.	NB: It is extremely critical to avoid iv air bubbles in all patients with intracardiac shunts. Meticulous attention must be paid to clearing the iv tubing and stopcocks of any bubbles to avoid paradoxical air embolism and possible stroke. Have blood available in the OR. Blood transfusion may be required in patients < 10 kg.
Monitoring	Standard monitors (see p. D-1). Cerebral oximetry O₂ sat probes (two sites) Arterial line CVP line Urinary catheter ACT monitoring TEE	ABG, electrolytes, and Hct should be checked as needed during the procedure. Place at least two O₂ probes to ensure readings during critical times. Avoid dorsalis pedis and posterior tibial arterial lines (inaccurate 2° spasm post-CPB). Femoral arterial line may be used. Double-lumen CVP in IJ preferable. TEE monitoring is used to assess anatomy and repair. On CPB, if the aorta is not cross-clamped, monitor for intracardiac air.
Positioning	[check mark] and pad pressure points [check mark] eyes
Pre-CPB	Heparinization (200-400 U/kg) [check mark] ACT > 480 sec [check mark] NMB [check mark] UO	Confirm that antibiotics have been given 30-60 min before skin incision and repeat q 4-6 h per protocol. If a regional technique is used, allow for a minimum of 60 min between needle placement and heparinization.
CPB	Ventilation stopped Hypothermia [check mark] sufficient analgesia/sedation [check mark] adequate flow and pressure during CPB [check mark] face for venous congestion [check mark] ABG and ACT [check mark] UO [check mark] blood availability	The patient is not actively cooled for secundum ASD closure. Temperature is allowed to drift to 33-34°C during CPB. Supplemental fentanyl/midazolam may be handed to the perfusionist and administered directly into the CPB circuit.
Transition off CPB	Rewarming [check mark] sufficient analgesia/sedation Vasoactive infusions started at 34-35°C. Flush lines. Zero transducers. Suction ETT. Resume ventilation. [check mark] ABG	Surgeon will de-air heart, and this maneuver is monitored with TEE. Observe inflation of both lungs. Turn on vaporizer. Vasoactive infusions (e.g., dopamine 3-5 mcg/kg/min) may be started but are not always necessary in uncomplicated cases.
Post-CPB	Reversal of heparin with protamine [check mark] UO ± Modified ultrafiltration (MUF)	1 mg of protamine will reverse 100 U of residual heparin. MUF uses the CPB machine to remove excess water and inflammatory mediators. It has been shown to transiently ↓ postop edema and improve cardiopulmonary function. This technique is not routinely performed at Stanford.
Complications	Air embolism (VAE) Supraventricular dysrhythmias Heart block Ventricular dysfunction	Potential for paradoxical embolization Likely 2° atriotomy

POSTOPERATIVE

Complications

Bleeding

Tests

ABG

Electrolytes; Hct

CXR

Suggested Readings

1. Allen HD, Driscoll DJ, Shaddy RE, et al: Moss and Adams’ Heart Disease in Infants, Children, and Adolescents, 7th edition. Lippincott Williams & Wilkins, Philadelphia: 2007.

2. Bacha EZ, Hijazi AM: Hybrid procedures in pediatric cardiac surgery. Seminars in thoracic and cardiovascular surgery. Pediatric Cardiac Surgery Annual 2005: 78-85.

3. Boltz MG, Hammer GB, Andropoulos DB: Regional anesthesia and postoperative pain management. In: Andropoulos DB, Stayer SA, Russel L, et al, eds. Anesthesia for congenital heart disease, 2nd edition. Blackwell: 2010, 356-70.

4. Chaudhary V, Chauhan S, Choudhury M, Kiran U, Vasdev S, Talwar S: Parasternal intercostals block with ropivacaine for postoperative analgesia in pediatric patients undergoing cardiac surgery: a double-blind, randomized, controlled study. J Cardiothorac Vasc Anesth 2012; 26:439-42.

5. DiNardo JA, Zvara DA: Congenital heart disease. Anesth for Cardiac Surgery, 3rd edition. Blackwell, Malden MA: 2008, 167-251.

6. Gadhinglajkar S, Sreedhar R, Jayakumar K, Misra M, Ganesh S, Mathew T: Role of intraoperative echocardiography in surgical correction of the superior sinus venous atrial septal defect. Ann Card Anesth 2010; 13:59-63.

7. Peterson KL, DeCampli WM, Pike NA, Robbins RC, Reitz BA: A report of 220 cases of regional anesthesia in pediatric cardiac surgery. Anesth Analg 2000; 90:1014-19.

8. Reitz BA, Yuh DD, eds: Congenital Cardiac Surgery. McGraw-Hill, New York: 2002.

9. Torracca L, Ismeno G, Alfieri O: Totally endoscopic computer-enhanced atrial septal defect closure in six patients. Ann Thorac Surg 2001; 72(4):1354-7.

10. Walker SG: Anesthesia for left-to-right shunt lesions. In: Andropoulos DB, Stayer SA, Russel L, Mossad EB, eds. Anesthesia for Congenital Heart Disease, 2nd edition. Blackwell, Chichester, UK: 2010, 373-97.

11. Wilson NJ, Smith J, Prommete B, et al: Transcatheter closure of secundum atrial septal defects with the amplatzer septal occluder in adults and children-follow-up closure rates, degree of mitral regurgitation and evolution of arrhythmias. Heart Lung Circ 2008; 17(4):318-24.

SURGERY FOR ATRIOVENTRICULAR CANAL DEFECT

SURGICAL CONSIDERATIONS

Description: Atrioventricular (A-V) canal defects comprise a spectrum of congenital cardiac anomalies stemming from the embryonic maldevelopment of endocardial cushions. This leads to the absence of septal tissue immediately above and below the level of the A-V valves and defects in the A-V valves in continuity with these septal defects. Partial A-V canal defects (or ostium primum atrial septal defects) involve the atrial septum and mitral valve, whereas complete A-V canal defects involve the atrial and ventricular septa and have a common atrioventricular valve. Intermediate or transitional A-V canal have varying degree of pathology between the above two common patterns. Pathophysiologically, these defects result in L → R shunting at the atrial and/or ventricular levels, leading to pulmonary HTN and CHF. A-V valvular insufficiency is also frequently observed with these defects, contributing to the early development of CHF.

Palliative repair of A-V canal defects consists of pulmonary artery banding (Fig. 12.4-2) to reduce excessive pulmonary blood flow. Palliation is rare and is reserved for very small infants with complicating conditions, such as RSV and
other pneumonias. Total correction is now performed routinely, even in neonates. Repair consists of the closure of atrial and ventricular septal defects (VSDs) with closure of the cleft in the anterior leaflet of the mitral valve and repair of associated defects, such as a patent ductus arteriosus (PDA) or secundum atrial septal defect (ASD). The septal defects may be repaired with either a “two-patch technique,” consisting of a Dacron or pericardial patch on the ventricular septum and pericardial patch on the atrial septum, or a single patch (pericardium) covering both ASDs and VSDs. A modified single-patch technique where the A-V valve is plastered down to the ventricular septum is currently used by some surgeons.

Figure 12.4-2. Placement of pulmonary artery band. PA = pulmonary artery; Ao = aorta; MPA = main pulmonary artery; LPA = left pulmonary artery; LA = left atrial. (Reproduced with permission from Kaiser LR, Kron IL, Spray TL, eds: Mastery of Cardiothoracic Surgery. Lippincott-Raven, Philadelphia: 1998.)

Partial A-V canal defects: Exposure is obtained through a standard median sternotomy. CPB is instituted with aortic cross-clamping and cardioplegic arrest. Through a right atriotomy, the mitral valve cleft is sutured. A pericardial patch is placed across the top of the ventricular septum, around the coronary sinus orifice, and along the free edge of the superior portion of the ASD. The atriotomy is closed and the aorta unclamped after de-airing. The patient is rewarmed and weaned from bypass.

Complete A-V canal defects: Following median sternotomy, CPB is instituted with aortic cross-clamping and cardioplegic arrest. In the single-patch technique, one patch is used to close both the ASD and VSD components. The anterior and posterior bridging leaflets often are divided and resuspended to the patch, thereby creating two separate valves. The cleft in the left AV valve is usually closed. If AV valve regurgitation is present, repair is undertaken. In the two-patch technique, two separate patches are used to close the ASD and VSD, and the common AV valve is sandwiched in between the two patches. Repair of AV valve is the same in either technique. Closure of the right atrium, de-airing, aortic unclamping, rewarming, and resuscitation of the heart are commenced, and CPB is discontinued. Closure proceeds in the standard fashion. In ˜5% of patients with complete A-V canal defects, tetralogy of Fallot (TOF) or left ventricular outflow tract obstruction (LVOTO) has to be addressed surgically.

Usual preop diagnosis: A-V canal defects (complete, intermediate, or partial); endocardial cushion defects

▪ SUMMARY OF PROCEDURES

	Partial A-V canal Defect	Complete A-V canal Defect
Position	Supine	⇚
Incision	Median sternotomy/right anterolateral thoracotomy	Standard median sternotomy
Unique considerations	None	Repair performed through a right atriotomy; no ventriculotomies required.
Antibiotics	Cefazolin 25 mg/kg q 4 h	⇚
Surgical time	Aortic cross-clamp: 30-40 min Total: 1.5-2 h	Aortic cross-clamp: 60-80 min Total: 2.5-3 h
Closing considerations	Chest tube in pericardial space; temporary ventricular pacing wire; possibly right or left atrial line for monitoring	⇚
EBL	Moderate	⇚
Postop care	ICU for 1-2 d, with 12- to 24-h assisted ventilation; minimal need for inotropes.	1- to 3-d assisted ventilation; pulmonary HTN protocol, including hyperventilation and sedation; need for pulmonary vasodilators (e.g., NO) is uncommon; use of inotropes for adequate CO. Avoid excessive volume to prevent distension and mitral valve regurgitation.
Mortality	0-1%	1-2%
Morbidity	Transient heart block Atrial dysrhythmias Hemorrhage Infection	Pulmonary vasospasm Right heart dysfunction Mitral valve regurgitation Low CO Heart block/atrial dysrhythmias Residual VSD Hemorrhage
Pain score	6-10	6-8

▪ PATIENT POPULATION CHARACTERISTICS

Age range	1-20 yr (usually 2-3 yr)	2-6 mo (occasionally older; rarely, adults)
Male:Female	1:1	⇚
Incidence	0.5-1% of congenital heart defects	⇚
Etiology	Down syndrome: Rare, in patients with partial A-V canal defect	Commonly associated with Down syndrome (75% in patients with complete A-V canal defect)
Associated conditions	Left A-V valve insufficiency	Pulmonary HTN, left A-V valve insufficiency, minor associated cardiac anomalies (e.g., PDA or ASD); major associated anomalies (e.g., TOF, LVOTO)

ANESTHETIC CONSIDERATIONS

PREOPERATIVE

Pathophysiology	A-V canal defects may be partial, transitional, or complete. The partial A-V canal has no interventricular communication and has an ostium primum ASD. There is often a cleft in the anterior leaflet of the mitral valve → MR. The complete A-V canal has communications at both the atrial and ventricular levels with a single A-V valve that is regurgitant. The transitional AVC has a pathology in between the 2 ends of the spectrum. The degree of L → R shunting depends on the size of the defect, the pressure gradient between the chambers, and the PVR/SVR. Patients with large L → R shunts are at risk of developing pulmonary HTN, requiring early surgical correction.
Respiratory	[check mark] for pulmonary congestion, frequent URIs, tachypnea, diaphoresis on feeding, FTT. Pulmonary HTN can be present in patients with partial or complete A-V canal defects. Tests: CXR: enlarged heart + increased pulmonary markings
Cardiovascular	Complete A-V canal → CHF and biventricular failure. Tests: ECG: RAE, RVE; ECHO diagnostic; rarely cardiac cath may be indicated to assess PVR.
Down syndrome	A-V canal defects account for 40% of cardiac defects in the Down syndrome patient. These patients are at risk of atlantoaxial instability (20%); therefore, avoid excessive flexionextension of the head and neck. Additional airway considerations (subglottic stenosis, large tongue, hypotonia) make these patients unsuitable for fast-tracking and early extubation. Furthermore, trisomy 21 patients are more prone to developing PVOD/pulmonary HTN resulting in an increase in the PVR/SVR ratio with the possibility of developing bidirectional shunting or, as a late finding, shunt reversal (R → L).
Laboratory	See ASD, p. 1234.
Premedication	Midazolam 0.5-0.75 mg/kg po.

INTRAOPERATIVE

Anesthetic technique: GETA

Induction	In children with small defects, no severe MR, or in the absence of PVOD, a mask induction with sevoflurane in air and O2 is acceptable. Otherwise, an iv induction with fentanyl provides more stable hemodynamics. If the iv is in place, ketamine 1-2 mg/kg or fentanyl 5-10 mcg/kg and rocuronium 1 mg/kg may be used. Verify ETT position (see p. D-2). In children with Down syndrome, anticipate difficult airway and atlantoaxial instability. Excessive neck flexion should be avoided in this population. The non-Down partial A-V canal patients may be candidates for early extubation if the intracardiac defects are small and surgery was uncomplicated. In this case, induction and maintenance regimes should be tailored accordingly (see ASD).
Maintenance	Air-oxygen with volatile anesthetic and narcotics is the standard. In patients requiring postop mechanical ventilation, fentanyl 50-100 mcg/kg total, rocuronium prn, and midazolam (0.1-0.2 mg/kg) ± volatile agent may be used.
Emergence	Patients undergoing repair of complete A-V canal defects are seldom suitable for fast-tracking. On conclusion of procedure, the patient is taken to CVICU, intubated, ventilated, sedated, and monitored, with emergency drugs and airway equipment immediately available.
Blood and fluid requirements	IV: 22-24 ga × 2 LR @ TKO Blood products
Monitoring	See ASD, p. 1235. TEE	TEE is used to assess left A-V valve regurgitation, valvular function, residual shunt, and ventricular function.
CPB	Management of CPB is discussed in Intraoperative Considerations for ASD, p. 1235.	In the immediate post-CPB period, TEE exam is valuable for evaluation of ventricular function and residual mitral valve regurgitation.
Transition off CPB	[check mark] rewarming [check mark] sufficient analgesia/hypnosis [check mark] vasoactive infusions started at 34-35°C [check mark] Flush lines [check mark] Zero transducers [check mark] Suction ETT [check mark] Resume ventilation	Surgeon will de-air heart, and this maneuver is monitored with TEE. Turn on vaporizer. Vasoactive infusions may be started but are not always necessary in uncomplicated cases. Dopamine 3-5 mcg/kg/min, milrinone 0.5 mcg/kg/min Observe inflation of both lungs. In patients with PVOD, there is a significant potential for pulmonary HTN—be ready to assist with ventilatory measures, ± pharmacological interventions. → NO or milrinone (> reduction of PVR vs. SVR).
Complications	Air embolism A-V block, ventricular dysfunction Persistent bleeding Pulmonary HTN	Avoid air embolism in A-V canal patients (potential for shunt reversal → paradoxical embolization). A-V block may be temporary 2° edema and/or cardioplegic arrest. Permanent injury can occur to the conduction system at the A-V node or bundle of His with repair of the VSD. Temporary atrial and ventricular pacing wires are placed. Ventilatory measures for managing PHTN aim to ↓ PVR independently of SVR. A combination of hyperventilation (PaCO₂ 20-30 mm Hg), alkalosis (pH ˜7.5-7.6), high FiO₂, PaO₂ > 60 mm Hg, and low PIP/PEEP usually achieve this goal. Pharmacological measures such as inhaled NO, prostacyclins, phosphodiesterase inhibitors, as well as endothelin antagonists, may be necessary to ↓ PVR in select patients. High PEEP or TV → ↑ intrathoracic pressure, thereby ↓ systemic venous return, while at the same time ↑ RV afterload, both of which could be detrimental in the setting of pulm HTN. Since control of ventilation is the most reliable way to manipulate PVR, ventilatory measures represent a key concept of anesthetic management of cardiac lesions in which balancing PVR over SVR is crucial (e.g., large VSD, CAVC, truncus arteriosus).

POSTOPERATIVE

Complications

Residual VSD/ASD

AV valve regurgitation

Tests

TEE

Analysis of postrepair function is best done by TEE.

Suggested Readings

1. Allen HD, Driscoll DJ, Shaddy RE, et al. eds: Moss and Adams’ Heart Disease in Infants, Children, and Adolescents, 7th edition. Lippincott Williams & Wilkins, Philadelphia: 2007.

2. Bacha EA, Hijazi ZM: Hybrid procedures in pediatric cardiac surgery. Seminars in thoracic and cardiovascular surgery. Pediatr Cardiac Surg Annu 2005: 78-85.

3. Boltz MG, Hammer GB, Andropoulos DB: Regional anesthesia and postoperative pain management. In: Andropoulos DB, Stayer SA, Russel L, et al, eds: Anesthesia for Congenital Heart Disease, 2nd edition. Blackwell, Malden, MA: 2010, 356-70.

4. Diaz LK: Anesthesia and postoperative analgesia in pediatric patients undergoing cardiac surgery. Pediatric Drugs 2006; 8:223-33.

5. DiNardo JA, Zvara DA: Congenital heart disease. In: Anesthesia for Cardiac Surgery, 3rd edition. Blackwell, Malden, MA: 2008, 167-251.

6. El-Morsy GZ, El-Deeb A, El-Desouky T, et al: Can thoracic paravertebral block replace thoracic epidural block in pediatric cardiac surgery? A randomized blinded study. Ann Card Anesth 2012; 15:259-63.

7. Kouchoukos NT, Blackstone EH, Doty DB, et al: Atrial septal defect. In: Kouchoukos NT, Karp RB, Blackstone EH, Doty DB, Hanley FL, eds: Kirklin/Barratt-Boyes Cardiac Surgery, 3rd edition. Churchill Livingstone, Philadelphia: 2003, 800-49.

8. Reitz BA, Yuh DD, eds: Congenital Cardiac Surgery. McGraw-Hill, New York: 2002.

9. Walker SG: Anesthesia for left-to-right shunt lesions. In: Andropoulos DB, Stayer SA, Russel L, Mossad EB, eds. Anesthesia for Congenital Heart Disease, 2nd edition. Blackwell, Chichester, UK: 2010, 373-97.

SURGERY FOR VENTRICULAR SEPTAL DEFECT

SURGICAL CONSIDERATIONS

Description: Ventricular septal defect (VSD) is the most common congenital cardiac anomaly. VSDs can occur anywhere in the interventricular septum (Fig. 12.4-3). One of the most common locations is the perimembranous (conoventricular) in the region of membranous septum near the tricuspid and aortic valves. Supracristal (subarterial) defects are common in the Pacific Rim population. Muscular defects occur in the inlet, trabecular, or outlet muscular septum. A-V canal defects are present under the septal leaflet of the tricuspid valve. Physiologically, these defects result in L → R shunting in proportion to the defect size. Untreated, this defect can → RV volume overload and CHF in infancy and irreversible pulmonary HTN later in life. As PVR rises, shunt reversal to a R → L shunt can occur, producing hypoxemia and cyanosis; this is known as Eisenmenger’s syndrome and occurs in ˜10% of untreated, nonrestrictive VSDs (rare). Moderate-to-large VSDs that remain open > 6 mo of age should be closed. Severe, intractable CHF in infants refractory to medical therapy (e.g., diuretics, digoxin), or ↑ PVR in infants > 6 mo are indications for earlier VSD repair.

Lillehei et al. performed the first successful VSD repairs using normothermic cross-circulation in 1955. Kirklin subsequently described successful VSD closure using extracorporeal circulation in 1957. VSD repair is performed now through a median sternotomy on CPB with bicaval cannulation. Deep hypothermia (18°C) with circulatory arrest is used in neonates < 1800 g to facilitate repair. After CPB and cardioplegic arrest have been instituted, a right atriotomy is created, and the VSD is visualized by retracting the tricuspid valve leaflets. The VSD is then closed with a patch (e.g., pericardium, Gore-Tex, Dacron), with care being taken not to place sutures through the nearby conduction fiber bundles or the aortic valve. After the repair is completed and the atriotomy is closed, standard de-airing maneuvers are performed, the aortic cross-clamp is released, and CPB is discontinued. The chest is then closed in the standard fashion.

Variant procedure or approaches: Supracristal defects may be more easily exposed through a pulmonary arteriotomy, while some inferiorly located muscular VSDs may be better accessed through a right ventriculotomy. Multiple VSDs or “Swiss cheese” ventricular septum can be a challenging surgical problem. Many can be closed with the approaches described above. Some may require a combined surgical and device closure. Palliative pulmonary artery banding may be required in Swiss cheese muscular VSD, with the hope that many of the VSDs may close spontaneously. At a 2nd stage, the remaining VSDs are closed and the PA band is removed.

Usual preop diagnosis: VSD

Figure 12.4-3. The right ventricular free wall has been resected to show the VSDs: conoventricular = perimembranous; conal septal = outlet septal (subpulmonary); inlet septal = A-V canal type. Muscular (trabecular) defects may be midmuscular, anterior, or apical. The penetrating bundle is closely related to the inferior margin of the conoventricular defect and diverges away from this margin into the trabecular septomarginalis beneath the muscle of Lancisi. (Reproduced with permission from Kaiser LR, Kron IL, Spray TL, eds: Mastery of Cardiothoracic Surgery. Lippincott-Raven, Philadelphia: 1998.)

▪ SUMMARY OF PROCEDURE

Position	Supine
Incision	Median sternotomy
Antibiotics	Cefazolin 25 mg/kg q 4 h
Surgical time	Aortic cross-clamp: 15-45 min Total: 2-3 h
Closing considerations	Routine closure with chest tube in the pericardial space; temporary ventricular pacing wire; possibly right/left atrial and/or pulmonary arterial lines for monitoring
EBL	Minimal-to-moderate
Postop care	Extubation in OR or within several h; 24-h monitoring in ICU.
Mortality	≤ 1%
Morbidity	Hemorrhage Low CO Atrial dysrhythmias Complete A-V heart block Residual shunting; tricuspid regurgitation
Pain score	6-8

ANESTHETIC CONSIDERATIONS

PREOPERATIVE

Pathophysiology	VSDs are classified by their location. Patients may be asymptomatic or may present with varying degrees of CHF ± pulmonary HTN, depending on the age of the patient, size of the VSD, and the flow across the VSD. Small VSDs, in which the flow is related to the size of the defect and in which there may be significant pressure gradient across the defect, are considered restrictive. These may close spontaneously in early childhood. Large VSDs in which the degree of L → R shunting is independent of the size and only determined by the PVR/SVR ratio are described as “nonrestrictive.” Patients with large VSDs present with CHF and other signs of pulmonary overcirculation once their Q_p:Q_s > 2.0. Cyanosis indicates pulmonary HTN and shunt reversal (Eisenmenger’s syndrome).
Cardiovascular and respiratory	Similar to patients with other L → R shunting lesions (ASD, ACV). [check mark] for signs and Sx of CHF and pulmonary overcirculation (include: tachypnea, frequent URIs, sweating during feeding, FTT, reduced exercise tolerance, fatigue). Children with small VSDs may be asymptomatic. A holosystolic murmur may be present (particularly in restrictive defects) and can be heard best at the left lower sternal border. Cyanosis is absent unless there is R → L shunting (suggesting pulmonary HTN). Tests: EKG, CXR, ECHO. If pulmonary NTH is suspected, cardiac catheterization is performed for measurement of PA pressures. If PA pressures are elevated, O2 and NO responsiveness is tested. VSDs may be closed surgically, via a device in the catheter (in the absence of pulmonary HTN), or with a hybrid procedural approach.
Laboratory	Hb/Hct: electrolytes (children on diuretic, digoxin Rx), others as indicated from H&P.
Premedication	Midazolam 0.5-0.75 mg/kg po may be useful.

INTRAOPERATIVE

Anesthetic technique: The anesthetic management of a patient with VSD (without pulmonary HTN and CHF) is similar to the patient with ASD. These patients may be candidates for fast-tracking and early extubation. Refer to fast-tracking in ASD section (see p. 1234). For patients with unrestrictive VSDs, avoid factors that ↓ PVR and ↑ shunt flow (i.e., high FiO₂, hyperventilation, ↓ pH). This will compromise DBP and thereby CPP. For patients who are not candidates for fast-tracking, the standard anesthetic is fentanyl 20-40 mcg/kg in divided doses with supplemental isoflurane before and during CPB. Additional midazolam (0.1-0.3 mg/kg) may be administered to prevent recall and awareness.

Blood and fluid requirements	IV: appropriate for patient size × 1-2 LR @ TKO Blood warmer T&C	Minimize administration of iv fluids. Both ventricles are volume-overloaded in large VSDs.
Monitoring	Standard monitors (see p. D-1). Arterial line Surgical LA line Surgical RA/PA line (to assess for elevated PA pressures) Urinary catheter ACT monitoring TEE	A transthoracic LA line may be placed by the surgeon if there is concern about postop mitral valve and LV dysfunction. In the immediate post-CPB period, TEE exam is valuable for evaluation of residual VSD and ventricular function.
Pre-CPB	See ASD (see p. 1235).
CPB	See ASD (see p. 1235).	Most VSDs are closed under mild/moderate hypothermic CPB (28-32°C).
Transition off CPB	See ASD (see p. 1235).
Post-CPB	Maintenance of adequate filling pressure (LA = 5-10 mm Hg) Temporary pacemaker wires TEE Pulmonary HTN	Placed in patients with conduction disturbances; pacemaker wires are placed routinely but may not be connected to a pacemaker. [check mark] for residual shunt and ventricular and valvular function, residual air.

POSTOPERATIVE

Complications

Persistent bleeding

Heart block

Ventricular dysfunction/failure

JET

May occur particularly after perimembranous VSD closure

Especially in patients with ventriculotomy Dx: TEE. Evaluate for need of esmolol, amiodarone, procainamide, [check mark] for cooling, paralysis.

Tests

ABGs

Electrolytes; Hct; coags prn

CXR

Suggested Readings

1. DiNardo JA, Zvara DA: Congenital heart disease. In: Andropoulos DB, Stayer SA, Russell L, Mossad EB, eds. Anesthesia for Cardiac Surgery, 3rd edition. Blackwell, Malden, MA: 2008, 167-251.

2. Kouchoukos NT, Blackstone EH, Doty DB, et al: Ventricular septal defect. In: Kouchoukos NT, Karp RB, Blackstone EH, Doty DB, Hanley FL, eds: Kirklin/Barratt-Boyes Cardiac Surgery, 3rd edition. Churchill Livingstone, Philadelphia: 2003, 850-910.

3. Walker SG: Anesthesia for left-to-right shunt lesions. Andropoulos DB, Stayer SA, Russel L, Mossad EB, eds. Anesthesia for Congenital Heart Disease, 2nd edition. Blackwell, Chichester, UK: 2010, 373-97.

SURGERY FOR PATENT DUCTUS ARTERIOSUS

SURGICAL CONSIDERATIONS

Description: Patent ductus arteriosus (PDA) usually is located between the proximal descending thoracic aorta and the main PA. Pathophysiologically, this results in L → R shunting and augmented pulmonary blood flow, which, if left untreated, may lead to pulmonary HTN and CHF. A relatively common congenital heart anomaly, comprising 12-15% of CHDs, PDA was first successfully ligated by Gross in 1938. Early administration of indomethacin may promote ductal closure in many premature infants, obviating surgical intervention; however, this mode of therapy generally is contraindicated in the setting of renal insufficiency or intracranial bleeding.

Surgical ductal closure is indicated for significant L → R shunting. The ductus usually can be exposed via a small, left, posterolateral thoracotomy in the 4th intercostal space or via the thoracoscopic approach. The ductus is identified and dissected with special care taken to avoid injury to the phrenic and left recurrent laryngeal nerves (Fig. 12.4-4). The ductus is interrupted with a surgical clip in neonates; in older children, the ductus is double- or tripleligated or divided between vascular clamps, and the ends are oversewn. A small thoracostomy tube is placed, and the thoracotomy is closed. The thoracostomy tube is removed in the OR immediately after the chest is closed or a few hours later.

Figure 12.4-4. PDA. A: Ductal dependency for pulmonary blood flow in pulmonary valvular atresia. The ductus arteriosus must be open for blood to enter the pulmonary arteries; as the ductus arteriosus closes, pulmonary blood flow is lost, and the patient becomes cyanotic. B: Dependence on the ductus arteriosus for perfusion of the distal aorta is shown in a patient with interrupted aortic arch. Left ventricular blood (oxygenated) is able to cross the VSD and enter the PA, where it mixes with right ventricular blood. The flow is then distributed to the branch PAs and across the ductus arteriosus to the descending aorta. (Reproduced with permission from Ungerleider RM, Plunkett MD, Gaynor JW: Congenital heart disease. In: Oldham KT, Colombani PM, Foglia RP, eds. Surgery of Infants and Children. Lippincott-Raven, Philadelphia: 1997).

Variant procedure or approaches: Percutaneous coil embolization and thoracoscopic clip ligation are standard alternative approaches. A robotic approach.

Usual preop diagnosis: PDA

▪ SUMMARY OF PROCEDURE

Position	Right lateral decubitus (in case of right-sided PDA with right aortic arch, left lateral decubitus)
Incision	Small left posterolateral thoracotomy; 3rd or 4th intercostal space
Antibiotics	Cefazolin 25 mg q 4 h
Surgical time	30-60 min
Closing considerations	Routine closure ± left thoracostomy tube
EBL	Minimal
Postop care	24-h observation in ICU; extubation in the OR or within several h
Mortality	Rare
Morbidity	Hemorrhage Recurrent laryngeal nerve injury Chylothorax
Pain score	6-8

ANESTHETIC CONSIDERATIONS

PREOPERATIVE

Closure of a PDA in the preterm infant is done at the bedside in the NICU. These patients are intubated, mechanically ventilated, hemodynamically unstable, and may require inotropic support. The premature infant requiring surgical closure of a PDA typically presents because indomethacin Rx has failed or is contraindicated. They often have primary pulmonary disease and multisystem organ problems. In these infants, the symptoms of large L → R shunt and pulmonary overcirculation → cardiac and respiratory failure and ventilator dependence. Ductal runoff causes ↓ diastolic blood pressure thereby compromising coronary perfusion pressure and distal organ perfusion. Older patients may be eligible for endovascular closure in the cath lab, leaving a small percentage for open surgical closure in the OR. Surgical closure may be performed with video-assisted thoracoscopy (VAT) or via thoracotomy. More recently, a hybrid approach has been applied in select patients in some centers. In older asymptomatic patients, risk of bacterial endocarditis necessitates closure.

Cardiovascular

Clinical presentation depends on the degree of L → R shunting which is dictated by the size of the ductus, its location, the PVR/SVR ratio, and any additional congenital cardiac abnormalities. An infant with a large ductus can present with CHF due to pulmonary overcirculation as well as with tachypnea, tachycardia, diaphoresis, failure to thrive (FTT), and hepatosplenomegaly. A continuous systolic murmur heard best at the left upper sternal border and widened pulse pressure with bounding pulses may be present.

Tests: CXR: Normal or cardiomegaly with ↑ PA size and ↑ pulmonary vascular markings. EKG: Normal or LVH/RVH. ECHO diagnostic: documents patency, evaluates left-sided cardiac chamber sizes and aortic arch anatomy, and estimates size of shunt.

Laboratory

Hct; others as indicated from H&P

Premedication

Not indicated in premature infants. Midazolam 0.5-0.7 mg/kg po 20 min prior to induction for children > 9 mo having routine PDA closure.

INTRAOPERATIVE

Anesthetic technique: Most children presenting for elective closure of PDA via thoracotomy are candidates for a thoracic epidural or, in patients < 10 kg, a caudal catheter can be threaded up to thoracic level 8-10. If a neuraxial block is contraindicated or not desired, a subcostal or paravertabrel block are reasonable alternatives for postop analgesia. In patients undergoing thoracoscopic closure, an epidural is not required. Although in small patients, retraction of the left lung may be sufficient to expose the surgical site. In patients >25 kg, placement of a DLT for selective ventilation of the right lung may be necessary to improve surgical access. In general, these patients are candidates for early extubation in the OR (see fast-track in ASD, p. 1234).

Induction	At the bedside of the preterm infant, anesthesia can be provided with ketamine (1-2 mg/kg) and muscle relaxant (e.g., rocuronium 1 mg/kg iv). Small doses of fentanyl (2-5 mcg/kg) may be given for supplemental analgesia. During lateral decubitus positioning, careful attention to the airway and close monitoring of BP is necessary. Children presenting in the OR for elective operation tolerate an inhalation induction with sevoflurane in 50% N₂O + O₂. Once the patient is anesthetized, iv access is established, followed by oral intubation, with administration of a muscle relaxant (e.g., rocuronium 1 mg/kg).
Maintenance	In patients for whom immediate postop extubation is planned, anesthesia is maintained with isoflurane in air + O₂ ± remifentanil (0.1-0.4 mcg/kg/min). Surgical retraction of the left lung, specifically if a VATS is performed, may require ↑ FiO₂ to prevent hypoxemia. Prior to lung isolation, hyperoxia and hypocarbia should be avoided to limit degree of L → R shunting.
Emergence	Older patients with an isolated PDA and no PVOD may be candidates for fast-tracking and may be extubated awake in the OR. In these cases, and if a thoracotomy has been performed, an effective regional anesthetic is particularly helpful for fast-tracking.
Epidural	Thoracic level T8-10 preferred. For neonates < 10 kg, a caudal catheter can be advanced to thoracic levels. Correct tip location should be verified either via US/Doppler or fluoroscopy. Then, an initial bolus of bupivacaine (0.25%) or ropivacaine (0.2%) at 0.3-0.5 mL/kg with either hydromorphone (5-10 mcg/kg) ± clonidine (0.5-1 mcg/kg) is administered (Max 20 mL, in intermittent doses titrated to hemodynamic tolerance). Subsequently, bupivacaine or ropivacaine may either be infused or bolused at a rate of 0.2-0.4 mg/kg/h depending on the patient’s age. [check mark] coagulation parameters prior to placing epidural/caudal catheter.
Blood and fluid requirements	IV: 22-24 × 1-2 Continue iv dextrose. Blood warmer T&C [check mark] for air bubbles	Usually blood loss is minimal but may become significant if the ductus is torn during ligation. Have blood available for rapid transfusion. Clear air bubbles from iv tubing and stopcocks (potential bidirectional shunt → paradoxical embolism).
Monitoring	Standard monitors (see p. D-1). ± Arterial line ± CVP line	Both blood pressure monitoring and pulse oximetry should be applied to the upper extremity, preferably the right arm (preductal) as well as the lower extremity (postductal) to detect inadvertent aortic ligation: → ↓ LE pulses/pressure/perfusion. Inadvertent PA occlusion → ↓ SpO₂ + ↓ ETCO₂.
Positioning	[check mark] and pad pressure points [check mark] eyes
Complications	Occlusion of aorta or PA Torn ductus → hemorrhage Residual PDA Only gold members can continue reading. Log In or Register to continue Share this: Click to share on Twitter (Opens in new window) Click to share on Facebook (Opens in new window) Related Related posts: Intracranial Neurosurgery Heart/Lung Transplantation Pancreatic Surgery Obstetric Surgery Hip, Pelvis, Upper Leg Surgery Pediatric Neurosurgery Tags: Anesthesiologist's Manual of Surgical Procedures May 23, 2016 \| Posted by drzezo in ANESTHESIA \| Comments Off on Pediatric Cardiovascular Surgery Full access? Get Clinical Tree Get Clinical Tree app for offline access Get Clinical Tree app for offline access