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Ann Thorac Surg 2002;73:331-339
© 2002 The Society of Thoracic Surgeons

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Review

First-stage palliation for hypoplastic left heart syndrome in the twenty-first century

^a Division of Pediatric Cardiothoracic Surgery, Children’s Hospital Medical Center, Cincinnati, Ohio, USA
^b Division of Pediatric Cardiology, Children’s Hospital Medical Center, Cincinnati, Ohio, USA

* Address reprint requests to Dr Pearl, Division of Pediatric Cardiothoracic Surgery, Children’s Hospital Medical Center, 3333 Burnet Ave, OSB-3, Cincinnati, OH 45229, USA
e-mail: pearj0{at}chmcc.org

	Abstract

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
Improved understanding of the postoperative physiology and experience with the surgical techniques and perioperative care of patients with hypoplastic left heart syndrome have resulted in improved outcomes. Over the past few years, numerous modifications to the intraoperative and postoperative management of these patients have been described. It is likely that in combination, these modifications and better understanding of the unique physiology after the Norwood procedure are responsible for decreasing early mortality. This review describes and discusses the current surgical and medical management of patients undergoing first-stage palliation for hypoplastic left heart syndrome and its variants.

	Introduction

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
The Norwood procedure and its modifications have become the most commonly used form of therapy for patients with hypoplastic left heart syndrome (HLHS) or other single-ventricle variants requiring aortic arch augmentation. Improved understanding of the postoperative physiology and experience with the surgical techniques and perioperative care of these patients have resulted in improved outcomes [1–3]. Nonetheless, early mortality still exceeds that for most other common congenital heart operations. Patients who survive after the Norwood procedure or its modifications are generally candidates for a bidirectional cavopulmonary anastomosis and for a subsequent total cavopulmonary connection (Fontan procedure). Over the past few years, numerous modifications to both the surgical and medical care of patients with HLHS have been described. It is likely that in combination, these modifications and better understanding of the unique physiology after the Norwood procedure are responsible for decreasing early mortality. This review describes and discusses the current care and management of patients with HLHS and its variants undergoing first-stage palliation.

	Prenatal diagnosis

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
Prenatal diagnosis of HLHS has become increasingly common. In the recent past, termination of the pregnancy was considered by many and chosen by some. With a current operative mortality rate of less than 25% for HLHS, elective termination is rare. Nevertheless, in utero diagnosis is beneficial in allowing the parents time to digest and understand information about the diagnosis and the surgical approach. In addition, arrangements for delivery at a hospital equipped to care for newborns with congenital heart disease can be made. Rapid institution of prostaglandins, transfer to a neonatal intensive care unit, and evaluation by a cardiologist are all critical in maintaining optimal surgical candidacy. In babies thought to have a restrictive atrial septal defect, immediate balloon septostomy shortly after delivery can be scheduled in advance. Although prenatal diagnosis is associated with better hemodynamic stability in the preoperative period, it has not been shown to improve surgical results [4]. It is possible that prenatal diagnosis allows newborns who are not optimal surgical candidates to remain in stable condition long enough to undergo Norwood palliation, whereas previously they would not have survived ductal closure and initial presentation.

	Preoperative care

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
Preoperative care of the infant with HLHS centers around maintaining a balance between systemic and pulmonary blood flow. This is most often accomplished with strategies to increase pulmonary vascular resistance (PVR) and maintain high total cardiac output, and may best be achieved by allowing the infant to remain extubated and spontaneously breathing. In fact, once initial resuscitation has been carried out, the majority of newborns with HLHS require little intervention before operation. For those who do exhibit signs of cardiopulmonary compromise because of pulmonary overcirculation, subambient oxygen (inspired oxygen fraction of 17% to 19%) is frequently administered either by hood or through an endotracheal tube. Supplementing with carbon dioxide (inspired carbon dioxide fraction of 1% to 4%) rather than the use of subambient oxygen is preferred by some [5]. Ventilator adjustments can be made to increase the carbon dioxide tension in intubated infants; sedation and paralysis is typically required, and care should be taken to avoid excessive hypoventilation, which can result in atelectasis. Positive end-expiratory pressure is also used to decrease pulmonary blood flow.

Close observation for end-organ dysfunction resulting from systemic hypoperfusion is crucial for infants exhibiting signs and symptoms of low systemic cardiac output. Infants who present in extremis because of initial misdiagnosis or who otherwise have compromised perfusion preoperatively may benefit from a period of time to recover renal and cardiac function. As PVR usually remains elevated in such circumstances, these infants can often be maintained without excessive pulmonary overcirculation for 7 to 14 days before surgical intervention is necessary. In addition, recent evidence suggests that preoperative use of glucocorticoids may be beneficial in stressed infants [6, 7].

Maintenance of nutrition is of critical importance. In general, our policy for patients with HLHS or other lesions dependent on ductal flow for systemic perfusion is to avoid enteral nutrition. Parenteral nutrition is begun as soon as possible with emphasis on maximizing caloric intake (120 to 140 kcal · kg^-1 · d^-1) as rapidly as possible.

In current practice, infants usually undergo initial surgical palliation between 3 and 8 days of life. It is unnecessary and probably unwise to operate within the first 48 hours of life, when the PVR is still quite elevated and adequate renal function is just being established. This also allows the mother to be discharged from the hospital to be with the infant in the perioperative period.

	Operating room anesthesia

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
The goal of anesthesia management in a child with HLHS is to maintain similar ventilation variables as used preoperatively. Anesthetic agents result in vasodilatation of the pulmonary and systemic vasculature and can markedly alter the ratios of pulmonary to systemic blood flow (Q_p/Q_s). Subambient oxygen should be maintained if used preoperatively. Once the sternotomy is performed, snaring of one pulmonary artery can be beneficial in maintaining and improving hemodynamics and avoiding the need to urgently place the child on cardiopulmonary bypass (CPB). The period from transport from the intensive care unit to placement on CPB can potentially be a very unstable time. Efforts to minimize this critical period are advantageous and include such measures as placing lines in the intensive care unit and avoiding central line placement in the operating room.

	Operative technique

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
Perhaps the greatest advances leading to the improved survival of patients with HLHS center on the conduct of the operation and the immediate postoperative care. Although the goals of operative therapy remain constant among surgeons and institutions, specific techniques to accomplish them vary. The goals of surgical intervention include the following: relief of all aortic arch obstruction; creation of an unobstructed ventricular to neo-aortic outlet; creation of unrestricted pulmonary venous return through a large atrial communication; and provision of a secure and regulated source of pulmonary blood flow with a systemic–pulmonary artery shunt.

Aortic arch reconstruction
In general, three methods of aortic arch reconstruction have been described. The Norwood procedure and its modifications [8] and the Lamberti modification [9] involve the use of a homograft patch to augment the aortic arch. In the Lamberti modification, the proximal aorta and pulmonary artery are transected, and an end-to-end anastomosis is created between the proximal neo-aorta and the augmented proximal arch. Either technique requires placement of an adequate patch that must extend distally beyond ductal tissue. Care must be taken to avoid placing excessive patch material, as this is thought to contribute to early and late arch obstruction, reportedly as high as 20% to 25% [10, 11].

The third method is direct anastomosis without the use of a homograft augmentation patch as described by Fraser and Mee [12], which by report has a low incidence of late arch obstruction [13]. However, using similar techniques without prosthetic patch material, Ishino and colleagues [11] at Birmingham Children’s Hospital (UK) described in 1999 an incidence of aortic arch obstruction of 23% in 120 patients. This figure is identical to the incidences of arch obstruction with the use of exogenous tissue for arch reconstruction in other studies [14–16].

Concern over left pulmonary artery and left bronchial compression by the no-patch technique has been raised, but the problem has not been recognized clinically as occurring with an increased frequency compared with patch repair techniques [13].

In patients with a very tight coarctation with a posterior shelf involving most of the circumference of the aorta, we have resected this narrow segment, performed an end-to-end anastomosis along the back wall, and then augmented anteriorly with a homograft patch.

Closure of pulmonary artery bifurcation
Closure of the pulmonary artery bifurcation is done either primarily or with a patch of homograft. In reported series with either approach, left pulmonary artery stenosis requiring augmentation at the time of the Glenn shunt is not infrequent [1]. Avoidance of this problem entirely remains elusive. However, a useful technique that can allow easier exposure for pulmonary artery repair at the time of the Glenn shunt is the placement of a small piece of Gore-Tex (W. L. Gore & Associates, Flagstaff, AZ) membrane between the underside of the neo-aorta and the pulmonary artery bifurcation and ductal remnant.

Systemic–pulmonary artery shunt
Increased understanding of post-Norwood physiology has resulted in the use of smaller shunts. In infants weighing more than 3.5 kg, a 3.5-mm shunt is used. In general, for infants less than 3.0 kg in weight, we routinely place a 3.0-mm Gore-Tex shunt, which originates near the innominate–subclavian artery junction. On occasion, for very small infants, a classic Blalock-Taussig shunt is used. Choice of shunt size for infants between 3 and 3.5 kg can be difficult. Other factors such as size of the subclavian or innominate artery, presence of an aberrant right subclavian artery, and preoperative condition of the infant including the status of the lungs, and PVR and any coexisting disease can influence shunt size selection. In smaller children or those with an aberrant right subclavian artery, early postoperative pulmonary blood flow can be limited more by the size of the inflow vessel than by the size of the shunt. Using a somewhat longer shunt in a smaller patient may also help prevent excessive pulmonary blood flow. In general, the distal shunt is placed on the proximal right pulmonary artery, but on occasion, we have placed it directly into the bifurcation and resected some of the redundant ductal tissue.

In addition to the early hemodynamic instability associated with a larger shunt, evidence suggests that the long-standing ventricular volume overload associated with a high Q_p/Q_s is detrimental to long-term ventricular function. With the use of smaller shunts, it may be necessary to accept lower initial saturations and the likelihood that the infant will require a cavopulmonary anastomosis at a younger age. Following this policy, however, we have rarely found it necessary to place a Glenn shunt required for cyanosis before the patient is 4 months old. More commonly, excessive pulmonary flow has resulted in ventricular enlargement and failure, thus prompting early referral for a Glenn shunt.

In the rare patient who is severely desaturated (oxygen saturation < 55% to 60%) in the early postoperative period, inhaled nitric oxide has proved useful to improve saturation. It is not uncommon in these infants, however, to see a transition from a state of elevated PVR to overcirculation physiology as the PVR decreases. Care must be taken to watch for this transition, which can occur as early as 6 to 12 hours postoperatively, and to adjust therapy.

	Intraoperative management

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
Until recently, complex arch reconstruction such as that to repair HLHS required an obligatory period of deep hypothermic circulatory arrest (DHCA). Although circulatory arrest times of 35 to 40 minutes for the Norwood procedure have been reported, arrest times for the most part are on the order of 50 to 80 minutes [1]. Several studies [17–20] evaluating the effects of prolonged DHCA clearly demonstrated long-term neurologic sequelae including decreased cognitive ability and motor skills. Excepting a few congenital operations such as the Norwood procedure, most congenital repairs can be performed without DHCA if desired. In addition to the neurologic issues, DHCA also commits the lungs, kidneys, liver, and abdominal viscera to extended periods of cold global ischemia. The combination of these considerations and marginal tissue perfusion in the early postoperative period makes it not surprising that postoperative renal insufficiency is common in these infants.

Selective regional perfusion and retrograde cerebral perfusion have frequently been used in adult aortic arch surgical procedures to decrease neurologic sequelae [21–25]. However, only recently have similar techniques been described to limit the period of DHCA for pediatric patients, specifically patients undergoing Norwood palliation. The technique of selective regional perfusion was described initially by Imoto and associates [26] and very shortly thereafter by Pigula and colleagues [27]. In the former study, in addition to cannulation of the shunt to maintain cerebral perfusion, cannulation of the descending aorta was also done to maintain lower-body perfusion. The latter method, and the approach we currently practice, involves upper-body regional perfusion alone. Clinical experience has demonstrated substantial blood return from the descending aorta, and this suggests that some lower-body perfusion occurs as well with selective regional perfusion. Using near-infrared spectroscopy, Pigula and coauthors [27] demonstrated significant decreases in cerebral blood volume and oxygen saturation in patients undergoing DHCA compared with those receiving regional perfusion. Further objective data supporting the use of low-flow regional perfusion over DHCA was provided by van der Linden and co-workers [17], who demonstrated significantly increased cerebral lactate release in patients having DHCA versus a minimal increase in patients in the low-flow group.

To employ this technique, the systemic shunt anastomosis is performed either prior to CPB or during cooling on CPB established through traditional ductal cannulation. Once cooled, low-flow bypass (50 mL/min) is maintained through the shunt with the arch vessels snared. Flow rates of 50 mL/kg (10 to 20 mL · kg^-1 · min^-1) are maintained. The specifics of the technique can be found in the report by Pigula and coauthors [27].

This technique allows the entire procedure to be performed with little or no circulatory arrest time. In our experience with selective regional perfusion, the mean DHCA time has been less than 15 minutes and is used for atrial septectomy, retrograde cardioplegia catheter placement, and cannula repositioning. Hanley and associates [28] have further modified this technique to avoid any period of circulatory arrest by placing the proximal shunt prior to initiating CPB and using bicaval cannulation to allow atrial septectomy without DHCA. To avoid any period of DHCA and bicaval cannulation, the atrial septectomy can be performed with sucker bypass. However, in our experience, it is not infrequent for the infant with HLHS to have some instability shortly after sternotomy that requires placement on CPB through traditional approaches. In these patients, it is not worth the added stress of marginal perfusion to insert the proximal shunt prior to CPB. A bifurcated arterial line allows for conversion from shunt perfusion to perfusion through the neo-aorta with no interruption of perfusion once the repair is completed.

Although no randomized studies supporting the benefits of regional perfusion are available, clinical observations suggest earlier return of renal function and less hemodynamic instability in regionally perfused patients. In addition, the data of van der Linden and colleagues [17] and of Pigula and coauthors [27] provide objective evidence of improved cerebral metabolic activity. A lower superior vena cava saturation has been noted in the first few hours after bypass despite what appears to be good systemic perfusion. We speculate that this represents an earlier return of cerebral aerobic metabolic activity in the regionally perfused infants. The lactate study by van der Linden and associates [17] supports this concept. Overall mortality has not been appreciably different with the use of selective regional perfusion, and experience is still too early to evaluate long-term neurologic outcome.

With any new technique, especially one requiring moving of cannulas and deairing, there are potential drawbacks. The technique can be somewhat cumbersome at first because of more tubing and cannulas in the operative field as well as blood return from the descending aorta. We have found it necessary to put a clamp on the distal aorta to prevent blood from entering the operative field. On occasion, it has been necessary to occlude the neoaorta pulmonary valve to prevent air from entering the right atrium and creating an air lock in the venous line. Alternatively, an active vent can be placed in the right atrium to maintain venous return during the period of low flow rather than use the venous cannula.

There are theoretical disadvantages to cerebral perfusion at deep hypothermic temperatures in addition to the effect of intermittent episodes of ischemia and reperfusion that occur as the cannula is repositioned. Cerebral perfusion when cerebral autoregulation is altered as during hypothermia may put the patient at increased risk for cerebral edema or intracranial bleeding. However, the adult experience with regional and retrograde cerebral perfusion has not demonstrated an increased risk of cerebral complications [23]. More detailed neurologic assessment in these patients is warranted.

Experimental and clinical evidence suggests that use of ph-stat management and hyperoxia during cooling are optimal when DHCA or low flow is employed [18, 29].

	Conduct of bypass and myocardial protection

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
Conduct of bypass
Techniques to decrease the inflammatory response to bypass are particularly applicable to newborn infants undergoing complex repairs [30, 31]. Such techniques have included leukocyte depletion [32–34], heparin-bonded or Carmeda-coated bypass circuits [35, 36], and monoclonal antibodies to various cytokines or white cell adhesion molecules [37, 38]. In practice, however, few of these methods have become clinically applicable. A recent clinical study evaluating a selectin blocker was unable to show an overall significant clinical benefit, although some specific variables were improved.

Intraoperative and perhaps preoperative use of glucocorticoids especially in patients with a complicated preoperative history may be helpful. Use of aprotinin to prevent postoperative bleeding appears to have additional anti-inflammatory benefits [39, 40]. Our subjective impression since switching from -aminocaproic acid to aprotinin for repairs in newborns is a marked difference in postbypass and postoperative bleeding and improved postoperative cardiopulmonary function. By avoiding multiple blood products, calcium fluxes related to blood product transfusions, and less dramatic fluid shifts, a steadier postoperative course has been noted. Extrapolating from the adult experience with aprotinin, initial concerns over graft patency and neurologic outcome have not been demonstrated provided heparinization is adequate [41, 42]. Both clinical and laboratory studies evaluating the benefits of preoperative steroids are underway at our institution.

Myocardial protection
Classically, many surgeons have used a single dose of antegrade cardioplegia for many repairs in neonates. Older data suggested that either single-dose cardioplegia or hypothermia alone is "adequate" protection, but the objective end points were less sophisticated than those currently available. In addition, many of these studies used crystalloid cardioplegia, which in newborns may actually be detrimental [43, 44]. Although the issue is still controversial and although many have demonstrated good results with single-dose cardioplegia in neonates, current laboratory data and clinical experience suggest that repeated doses of blood cardioplegia most likely provide optimal myocardial protection [45, 46]. Not only is myocardial function preserved, but coronary endothelial function may also be preserved. Data from our laboratory have demonstrated marked leukocyte-activity, apoptosis, and peroxynitirite formation after reoxygenation of hypoxic myocardium on CPB [47]. These data suggest that not only does inadequate myocardial protection affect early myocardial function, but also the presence of substantial numbers of apoptotic cells may have important long-term implications.

During aortic arch reconstruction, which accounts for the majority of operative time in the Norwood procedure, administration of additional doses of antegrade cardioplegia is not feasible. Retrograde cardioplegia has been shown to provide excellent myocardial protection in adults with coronary artery disease or those undergoing aortic valve or aortic root surgical procedures or both [45, 48]. Similarly, retrograde cardioplegia has also been demonstrated to protect the immature myocardium [48–50]. An earlier return of spontaneous cardiac function and lower doses of inotropic agents have been recognized in hearts protected with retrograde cardioplegia. Adequate myocardial protection, including the use of retrograde cardioplegia, and judicious use of topical hypothermia undoubtedly optimize myocardial recovery and hence may improve early and late outcome. Small 6F retrograde catheters are now available and can easily be placed directly into the coronary sinus at the time of atrial septectomy.

	Weaning from bypass and postoperative care

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
Probably one of the most important conceptual changes contributing to improved early outcome is understanding the balance between pulmonary and systemic flow. In the early Norwood experience, intraoperative and postoperative mortality was often attributed to acute pulmonary hypertensive crisis, which at the time was true to some extent. For this reason, it was customary to place 4- and even 5-mm shunts. Nitric oxide was also used prophylacticly in some centers. Over time, however, it became evident that postoperative instability in Norwood patients is more commonly due to either excessive pulmonary blood flow or overall low cardiac output from poor myocardial function. Pulmonary vasoreactivity still occurs, but CPB as currently practiced tends to be less injurious to the lungs than previously. Other than the presence of a clotted shunt, severe postoperative desaturation is usually related to overall low cardiac output, pulmonary venous desaturation, or a combination of both.

Understanding the importance of balancing systemic and pulmonary blood flow has led to increased tolerance of moderate postoperative cyanosis provided systemic perfusion remains good. Overall oxygen delivery may be better under these circumstances than in a well-saturated but poorly perfused patient. Understanding how to manipulate the Q_p/Q_s is critical to the successful management of a patient after a Norwood operation.

The use of adequate inotropic support to maintain overall cardiac output, systemic vasodilators to encourage systemic flow, and manipulation of PVR by ventilator management remain the cornerstones of postoperative management.

Inotropic support
Despite the use of retrograde cardioplegia, blood cardioplegia, and topical hypothermia, postoperative myocardial contractility is usually depressed despite a good technical repair. The use of ß agonists such as dopamine hydrochloride and epinephrine should be considered mandatory. Dobutamine hydrochloride (Dobutrex) and isoproterenol hydrochloride (Isuprel) are other options. In addition, as the immature myocardium is highly dependent on extracellular calcium, the use of a phosphodiesterase inhibitor such as amrinone or milrinone or calcium infusions can be helpful. Effective doses of inotropic agents vary widely among newborns. In general, the dose should be adjusted to gain maximum benefit before the addition of other agents. Concerns over -adrenergic stimulation and decrease in renal and mesenteric flow at high epinephrine doses can be partially alleviated by the use of vasodilators, as will be discussed.

Using an animal shunt model, Riordan and colleagues [51] demonstrated that whereas epinephrine at 0.1 µg · kg^-1 · min^-1 decreases Q_p/Q_s and increases oxygen delivery, dobutamine at 15 µg · kg^-1 · min^-1 increases Q_p/Q_s and decreases oxygen delivery presumably by acting as a pulmonary vasodilator. Our subjective clinical impression agrees with these findings in that epinephrine, often in combination with a systemic vasodilator, optimizes systemic oxygen delivery.

Further computer simulations by Austin in conjunction with researchers at Tel Aviv University [52] demonstrated several important findings: small increases in arterial oxygen saturation can be associated with large decreases in overall oxygen delivery; curves for myocardial oxygen consumption and Q_p/Q_s are similar; estimation of Q_p/Q_s from arterial oxygen saturation results in errors when there is pulmonary venous desaturation; and a linear relationship exists between the oxygen extraction factor and overall oxygen delivery. Charpie and colleagues [53] discussed the usefulness of following the oxygen extraction factor in patients after a Norwood operation.

The use of systemic vasodilators can increase systemic output and decrease the Q_p/Q_s without significantly decreasing mean arterial pressures [1, 54]. Tweddell and coauthors [54] examined the use of the long-acting vasodilator phenoxybenzamine hydrochloride and an earlier report by Reinoso-Barbero and associates [55] recommended the use of milrinone for both its inotropic and vasodilative properties. In a limited number of patients, the use of phenoxybenzamine was shown to result in a higher mixed venous oxygen saturation, a lower Q_p/Q_s, a narrower arteriovenous oxygen difference, and a lower indexed systemic vascular resistance than in controls. No difference in survival was noted. Tweddell and colleagues [54] concluded that phenoxybenzamine resulted in improved systemic oxygen delivery.

A potential concern over the use of phenoxybenzamine is related to its very long half-life. An exaggerated response could leave a particular patient profoundly hypotensive and unresponsive to -adrenergic stimulation. Furthermore, the occasional patient with decreased postoperative pulmonary blood flow can be dependent on increasing systemic vascular resistance to maintain adequate arterial saturations. For these reasons, we have opted to use a shorter-acting vasodilator such as sodium nitroprusside. However, those who routinely use phenoxybenzamine have not found excessive systemic vasodilatation to be a problem. Although phosphodiesterase inhibitors are also long acting, their effects can easily be countered by the use of -adrenergic agonists such as dopamine or epinephrine. We have found Nipride (sodium nitroprusside) to be very effective at increasing systemic perfusion and balancing the Q_p/Q_s in a patient after a Norwood procedure. Nipride is attractive in that it is very short acting and can be titrated easily. Despite individual preferences for a particular drug, the use of vasodilative agents after a Norwood operation is becoming an accepted concept.

To balance the Q_p/Q_s, objective data are required. The actual Q_p/Q_s ratio can be calculated by measurement of arterial saturation, mixed venous saturation, and pulmonary venous saturation. The superior vena cava saturation is used as a surrogate for mixed venous oxygen saturation, and in most cases the pulmonary venous saturation is assumed to be 90% to 95%. Ventilator manipulations used to affect the PVR can frequently lead to pulmonary venous desaturation, however. We [56] recently have demonstrated that in the period after a Norwood procedure, a pulmonary venous saturation of 95% or greater cannot be assumed for the purposes of calculating the Q_p/Q_s [56]. In these data, 32% of pulmonary venous oxygen measurements were lower than 95%, and 17 measurements in 8 patients were less than 90%. Arterial oxygen saturation correlated weakly with Q_p/Q_s (R² = 0.17) [56]. The computer model of Barnea and coworkers [57] indicated significant errors in calculating Q_p/Q_s when inaccurate pulmonary venous oxygen values were used. In most patients, we have found it helpful to directly measure pulmonary venous oxygen content by positioning the tip of one of the transthoracic atrial lines in the left inferior pulmonary vein while the atrial septectomy is being performed.

Others have attempted alternative methods to measure pulmonary and systemic flows after a Norwood operation. Migliavacca and colleagues [58] developed a method based on computational fluid dynamics to determine shunt flow after a Norwood procedure. However, poor correlation between shunt flow and aortic Doppler measurements make the determination of Q_p/Q_s dependent on saturation data.

The importance of balancing shunt flow is so critical that placement of an adjustable snare around the shunt has been tried by many and reported by Schmid and colleagues [59]. However, the potential risks of shunt thrombosis when snares are used as well as potential problems with infection from repeated mediastinal exploration for snare adjustment must be considered. On occasion, chest exploration with narrowing of a shunt has been lifesaving.

Placement of either a transvenous oximetry catheter or a single-lumen transatrial line in the distal superior vena cava allows measurement of the mixed venous saturation. The line should be close to the innominate–superior vena cava junction to avoid contamination from right atrial blood. Care should be taken to avoid placing the line into the innominate or jugular vein, as thrombosis has been documented from the use of these catheters.

Although the calculation of Q_p/Q_s can be valuable in guiding postoperative therapy in Norwood patients, clinical evaluation still represents the optimal modality. As the mathematical model of Barnea and coauthors [57] shows, if Q_p + Q_s is excellent (ie, good cardiac output), the range of Q_p/Q_s ratios that will result in adequate oxygen delivery is wider. These data indicate the importance of maintaining total cardiac output in addition to balancing the Q_p/Q_s ratio. The Q_p/Q_s calculation, although very helpful, should be used with other objective and subjective data in determining the management of these patients with very complex conditions. The optimal Q_p/Q_s ratio for single-ventricle physiology is in the range of 0.7 to 1.0.

Postoperative ventilator management
Manipulation of ventilator variables to affect PVR and optimize systemic oxygen delivery has traditionally been a focus of management in the post-Norwood period. Decreased minute ventilation, increased dead space, and inhaled carbon dioxide can all be used to establish a respiratory acidosis and thereby increase PVR [5, 60, 61]. Some animal models suggest that a relatively high arterial carbon dioxide tension (80 to 90 mm Hg) must be achieved to cause a significant decrease in Q_p/Q_s [62]. Other studies have shown significant improvement with an arterial carbon dioxide tension in the range of 55 mm Hg provided pH is maintained in the range of 7.3 [63]. Hypoventilation by the use of a low ventilatory rate, a low tidal volume, or increased dead space has the theoretical disadvantage of causing atelectasis, which can result in pulmonary venous desaturation. Positive end-expiratory pressure can also be used to increase PVR and to reduce the alveolar-arterial gradient.

Despite the emphasis on maintenance of a high PVR using these strategies, there are data to suggest that such an approach is often unnecessary. Mosca and colleagues [64] reported that respiratory alkalosis was common in the initial postoperative period and was not associated with adverse hemodynamic consequences. Furthermore, our observation that pulmonary venous desaturation is common after the Norwood operation implies that a low inspired oxygen fraction may actually be detrimental to systemic oxygen delivery if a decrease in arterial oxygen saturation is not offset by an increase in systemic flow. A likely explanation for the limited utility of ventilator manipulation in the control of Q_p/Q_s is that an appropriately sized shunt limits pulmonary flow, so that changes in the "downstream" resistance caused by these maneuvers are only minimally effective. Rather, manipulation of systemic vascular resistance, as discussed already, is a much more effective tool to control Q_p/Q_s. Nevertheless, for the patient who has major pulmonary overcirculation and particularly for the patient with unlimited pulmonary flow preoperatively, manipulation of PVR may be of substantial benefit.

Postoperative anticoagulation
We have not routinely heparinized patients after a Norwood procedure as we do our other patients with a shunt because of concerns about postoperative bleeding. Patients with lower saturations or in whom a 3.0-mm shunt was used are heparinized selectively once hemostasis has been achieved. Nevertheless, we have not had any early shunt thrombosis in our Norwood patients. For all patients, a regimen of aspirin therapy is started after chest closure 2 to 3 days postoperatively. With the use of aprotinin, postoperative bleeding has been minimal, and early heparinization would most likely be tolerated. In fact, the decrease in coagulopathy seen with our current management strategies may actually warrant more aggressive early postoperative anticoagulation.

Delayed sternal closure
As a routine, we have adopted a policy of leaving the chest open after stage-one palliation for HLHS. In general, delayed sternal closure is carried out by 48 to 72 hours postoperatively. An open chest policy was common, if not routine, in the early experience with the Norwood operation in many centers. Reasons for this included the relatively high mortality, the substantial incidence of reexploration for bleeding, and the general improved cardiopulmonary function seen in edematous newborns in whom the chest was left open. Other reasons included the ability to gain quick access to the heart in the case of cardiac arrest. With improved outcomes, decreased postoperative bleeding, and ultrafiltration to avoid excessive total-body water increases on CPB, the benefits of leaving the chest open are less obvious. Some surgeons now routinely close the chest at the time of stage-one palliation in neonates in stable condition. If delayed sternal closure is used, it is imperative to monitor ventilatory and hemodynamic indicators closely to verify that this maneuver is well tolerated. Sternal closure is associated with an increase in atrial pressure, peak inspiratory pressure, and ventilator support [65].

Mechanical support of patient after Norwood procedure
Despite the many advances and improving results with first-stage repair of HLHS, there are still patients who cannot be separated from CPB or whose condition deteriorates in the early postoperative period. Until recently, many surgeons believed that aggressive mechanical support of a failing patient after a Norwood operation was heroic, and usually futile. Failure to wean from CPB based on mechanical or technical aspects of the repair is unlikely to improve with mechanical support. However, patients with myocardial dysfunction thought to be reversible or those with reactive pulmonary hypertension or respiratory distress syndrome may benefit from a period of mechanical support. Jaggers and coauthors [66] from Duke University reported reasonable survival of patients supported with high-flow extracorporeal membrane oxygenation with the shunt left open after a Norwood procedure. These authors described the use of extracorporeal membrane oxygenation without an oxygenator as a means of ventricular support, using shunt flow for oxygenation.

If mechanical support (extracorporeal membrane oxygenation) is to be instituted, a period of hemostasis with heparin reversal off CPB is certainly desirable prior to reheparinization for support. Patients going straight from bypass to extracorporeal membrane oxygenation tend to have continued bleeding and poor outcomes. Monitoring postoperative lactate levels and other indicators of systemic perfusion such as mixed venous oxygen saturation may be helpful in determining when assist therapy is necessary. The use of assist therapy after a Norwood procedure remains a matter of surgeon and institutional choice.

Postoperative follow-up
Several studies [10, 11, 16] have clearly demonstrated that the incidence of aortic arch obstruction after the first- stage Norwood procedure is 20% to 25% by 6 months. The detrimental effect of increased afterload on a single ventricle with a systemic–pulmonary artery shunt cannot be emphasized enough. Hypertrophy and dilation of the ventricle occur, and tricuspid valve insufficiency develops. In addition to the pressure overload on the ventricle, an increased volume load is also placed by increased systemic afterload driving pulmonary blood flow. If undetected early, this combination can result in permanent damage to the single ventricle, thus making the patient a poor candidate for Glenn and Fontan operations and influencing long-term survival. Although echocardiography can detect arch obstruction, Fraisse and associates [10] demonstrated a 73% sensitivity, a 92% specificity, a 70% positive predictive value, and 88% accuracy. Echocardiography missed major arch obstruction in at least 5% of patients. As catheter-based interventional therapy can have a success rate of greater than 50% in relieving postoperative arch obstruction [16], some have advocated routine catheterization by 3 months of age for patients who have had a Norwood procedure. Not only can arch obstruction be definitively identified and treated if possible, but also preoperative Glenn data can be obtained. The Glenn shunt can then be performed between 4 and 6 months of age, or earlier if indicated. In arch obstruction that cannot be dilated or stented, surgical correction either simultaneously with the Glenn shunt or as a staged approach is required. For the often distal location of aortic arch obstruction, a subclavian patch aortoplasty through a left thoracotomy is an attractive option. The Glenn shunt can then be performed from the front without the need of cardiac or cerebral ischemic time.

Despite improved early outcome for first-stage palliation, there remains a small but important attrition rate after hospital discharge prior to second-stage palliation. In our experience, the incidence of late death is 11% prior to Glenn palliation. Close follow-up and early second-stage palliation are crucial in avoiding late death. We have had no early or late mortality after stage-two palliation, and 1 child underwent cardiac transplantation several months after a Glenn procedure. In regard to early mortality for stage-one palliation, the use of classic high-risk criteria proves fairly prognostic. Our overall mortality rate has been 30% over the past 3 years, but patients classified as low risk have had an early mortality rate of only 16% compared with 55% in our high-risk patients. Partly because of referral patterns and geographic considerations, 40% of our patients meet one or more criteria for high risk: restrictive atrial septal defect or age greater than 6 weeks; more than moderate atrioventricular valve regurgitation often combined with high preoperative inotropic requirements; and anomalous pulmonary venous drainage. All patients admitted with a diagnosis of HLHS have been offered and have undergone stage-one palliation. Only 1 patient has died prior to operation, and no patient has had transplantation as a primary procedure.

	Conclusions

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 
Recent advances in all aspects of pediatric heart surgery including preoperative, intraoperative, and postoperative management have resulted in mortality rates of less than 5% for most conditions. Even for lesions such as HLHS, there has been a reduction in early mortality rates from 50% or greater in even recent reports to less than 15% in some centers. It is remarkable that in response to what most considered unacceptable results, extensive effort was focused on studying HLHS and the Norwood operation. The improved understanding of the complex single ventricle and the post-Norwood physiology and the modified intraoperative techniques are now being applied to other lesions and repairs. Results can still improve, but we all should feel a sense of accomplishment for aggressively pursuing improved outcomes for these patients and their families.

	References

Top Abstract Introduction Prenatal diagnosis Preoperative care Operating room anesthesia Operative technique Intraoperative management Conduct of bypass and... Weaning from bypass and... Conclusions References

 

1. Bove E.L. Surgical treatment for hypoplastic left heart syndrome. Jpn J Thorac Cardiovasc Surg 1999;47:47-56.[Medline]
2. Breyman T., Kircher G., Blanz U., et al. Results after Norwood procedure and subsequent cavopulmonary anastomoses for typical hypoplastic left heart syndrome and similar complex cardiovascular malformations. Eur J Cardio-thorac Surg 1999;16:117-124.[Abstract/Free Full Text]
3. Daebritz S.H., Nollert G.D., Zurakowski D., et al. Results of Norwood stage I operation: comparison of hypoplastic left heart syndrome with other malformations. J Thorac Cardiovasc Surg 2000;119:358-367.[Abstract/Free Full Text]
4. Fesslova V., Nava S., Villa L. Evolution and long-term outcome in cases with fetal diagnosis of congenital heart disease. Heart 1999;82:594-599.[Abstract/Free Full Text]
5. Mora G.A., Pizarro C., Jacobs M.L., Norwood W.I. Experimental model of single ventricle. Influence of carbon dioxide on pulmonary vascular dynamics. Circulation 1994;90(5 Pt 2):II43-II46.
6. Lodge A.J., Chai P.J., Daggett C.W., et al. Methylprednisolone reduces the inflammatory response to cardiopulmonary bypass in neonatal piglets: timing of dose is important. J Thorac Cardiovasc Surg 1999;117:515-522.[Abstract/Free Full Text]
7. Dupuy P.M., Shore S.A., Drazen J.M., Frostell C., Hill W.A., Zapol W.M. Bronchodilator action of inhaled nitric oxide in guinea pigs. J Clin Invest 1992;90:421-428.
8. Norwood W.I., Lang P., Hansen D.D. Physiologic repair of aortic atresia-hypoplastic left heart syndrome. N Engl J Med 1983;308:23-26.[Medline]
9. Waldman J.D., Lamberti J.J., George L., et al. Experience with Damus procedure. Circulation 1988;78(5 Pt 2):III32-III39.
10. Fraisse A., Colan S.D., Jonas R.A., Gauvreau K., Geva T. Accuracy of echocardiography for detection of aortic arch obstruction after stage I Norwood procedure. Am Heart J 1998;135(2 Pt 7):230-236.[Medline]
11. Ishino K., Stumper O., De Giovanni J.J., et al. The modified Norwood procedure for hypoplastic left heart syndrome. Early to intermediate results of 120 patients with particular reference to aortic arch repair. J Thorac Cardiovasc Surg 1999;117:920-930.[Abstract/Free Full Text]
12. Fraser C.D., Jr, Mee R.B.B. Modified Norwood procedure for hypoplastic left heart syndrome. Ann Thorac Surg 1995;60:S546-S549.
13. Poirier N.C., Drummond-Webb J.J., Hisamochi K., Imamura M., Harrison A.M., Mee R.B. Modified Norwood procedure with a high-flow cardiopulmonary bypass strategy results in low mortality without late arch obstruction. J Thorac Cardiovasc Surg 2000;120:875-884.[Abstract/Free Full Text]
14. Meliones J.N., Snider A.R., Bove E.L., Rosenthal A., Rosen D.A. Longitudinal results after first-stage palliative surgery for hypoplastic left heart syndrome. Circulation 1990;82(5 Suppl):IV151-IV156.
15. Murdison K.A., Baffa J.M., Farrell P.E., Jr, et al. Hypoplastic left heart syndrome. Outcome after initial reconstruction and before modified Fontan procedure. Circulation 1990;82(5 Suppl):IV199-IV207.
16. Tworetzky W., McElhinney D.B., Burch G.H., Teitel D.F., Moore P. Balloon arterioplasty of recurrent coarctation after the modified Norwood procedure in infants. Catheter Cardiovasc Interv 2000;50:54-58.[Medline]
17. Van der Linden J., Astudillo R., Ekroth R., Scallan M., Lincoln C. Cerebral lactate release after circulatory arrest but not after low flow in pediatric heart operations. Ann Thorac Surg 1993;56:1485-1489.[Abstract]
18. Jonas R.A. Hypothermia, circulatory arrest, and the pediatric brain. J Cardiothorac Vasc Anesth 1996;10:66-74.[Medline]
19. Kern J.H., Hinton V.J., Nereo N.E., et al. Early developmental outcome after the Norwood procedure for hypoplastic left heart syndrome. Pediatrics 1998;102:1148-1152.[Abstract/Free Full Text]
20. Uzark K., Lincoln A., Lamberti J.J., Mainwaring R.D., Spice R.L., Moore J.W. Neurodevelopmental outcomes in children with Fontan repair of functional single ventricle. Pediatrics 1998;101(4 Pt 1):630-633.[Abstract/Free Full Text]
21. Testolin L., Roques X., Laborde M.N., Roques F., Mukai S., Bandet E. Moderately hypothermic cardiopulmonary bypass and selective cerebral perfusion in ascending aorta and aortic arch surgery. Preliminary experience in twenty-two patients. Cardiovasc Surg 1998;6:398-405.[Medline]
22. Esmalian F., Dox H., Sadeghi A., et al. Retrograde cerebral perfusion as an adjunct to prolonged hypothermic circulatory arrest. Chest 1999;116:887-891.[Abstract/Free Full Text]
23. Bachet J., Guilmet D., Goudot B., et al. Antegrade cerebral perfusion with cold blood: a 13-year experience. Ann Thorac Surg 1999;67:1874-1878.[Abstract/Free Full Text]
24. Higami T., Kozawa S., Asada T., et al. Retrograde cerebral perfusion versus selective cerebral perfusion as evaluated by cerebral oxygen saturation during aortic arch reconstruction. Ann Thorac Surg 1999;67:1091-1096.[Abstract/Free Full Text]
25. Ishino K., Kawada M., Irie H., et al. Single-stage repair of aortic coarctation with ventricular septal defect using isolated cerebral and myocardial perfusion. Eur J Cardio-thorac Surg 2000;17:538-542.[Abstract/Free Full Text]
26. Imoto Y., Kado H., Shiokawa Y., Fukae K., Yasui H. Norwood procedure without circulatory arrest. Ann Thorac Surg 1999;68:559-561.[Abstract/Free Full Text]
27. Pigula F.A., Nemoto E.M., Griffith B.P., Siewers R.D. Regional low-flow perfusion provides cerebral circulatory support during neonatal aortic arch reconstruction. J Thorac Cardiovasc Surg 2000;119:331-339.[Abstract/Free Full Text]
28. Hanley F.L. Regional low-flow perfusion provides cerebral circulatory support during neonatal aortic arch reconstruction. J Thorac Cardiovasc Surg 2000;119:337-339.
29. Pearl J.M., Thomas D.W., Grist G., Duffy J.Y., Manning P.B. Hyperoxia for management of acid-base status during deep hypothermia with circulatory arrest. Ann Thorac Surg 2000;70:751-755.[Abstract/Free Full Text]
30. Wan S., LeClerc J.L., Huynh C.H., et al. Does steroid pretreatment increase endotoxin release during clinical cardiopulmonary bypass?. J Thorac Cardiovasc Surg 1999;117:1004-1008.[Abstract/Free Full Text]
31. Wan S., LeClerc J.L., Vincent J.L. Inflammatory response to cardiopulmonary bypass: mechanisms involved and possible therapeutic strategies. Chest 1997;112:676-692.[Abstract/Free Full Text]
32. Lazar H.L., Zhang X., Hamasaki T., et al. Role of leukocyte depletion during cardiopulmonary bypass and cardioplegic arrest. Ann Thorac Surg 1995;60:1745-1748.[Abstract/Free Full Text]
33. Schmidt F.E., Jr, MacDonald M.J., Murphy C.O., Brown W.M., III, Gott J.P., Guyton R.A. Leukocyte depletion of blood cardioplegia attenuates reperfusion injury. Ann Thorac Surg 1996;62:1691-1697.[Abstract/Free Full Text]
34. Hayashi Y., Sawa Y., Nishimura M., et al. Clinical evaluation of leukocyte-depleted blood cardioplegia for pediatric open heart operation. Ann Thorac Surg 2000;69:1914-1919.[Abstract/Free Full Text]
35. Harig F., Feyrer R., Mahmoud F.O. Reducing the post-pump syndrome by using heparin-coated circuits, steroids, and aprotinin. Thorac Cardiovasc Surg 1999;47:111-118.[Medline]
36. Defraigne J.-O., Pincemail J., Larbuisson R., Blaffart F., Limet R. Cytokine release and neutrophil activation are not prevented by heparin-coated circuits and aprotinin administration. Ann Thorac Surg 2000;69:1084-1091.[Abstract/Free Full Text]
37. Shin’oka T., Nagashima M., Nollert G., et al. A novel sially Lewis X analog attenuates cerebral injury after deep hypothermic circulatory arrest. J Thorac Cardiovasc Surg 1999;117:1204-1211.[Abstract/Free Full Text]
38. Schmid R.A., Yamashita M., Boasquevisque C.H., et al. Carbohydrate selectin inhibitor CY-1503 reduces neutrophil migration and reperfusion injury in canine pulmonary allografts. J Heart Lung Transplant 1997;16:1054-1061.[Medline]
39. Diego R.P., Mihalakakos P.J., Hexum T.D., Hill G.E. Methylprednisolone and full-dose aprotinin reduce reperfusion injury after cardiopulmonary bypass. J Cardiothorac Vasc Anesth 1997;11:29-31.[Medline]
40. Hill G.E., Taylor J.A., Robbins R.A. Differing effects of aprotinin and -aminocaproic acid on cytokine-induced nitric oxide synthase expression. Ann Thorac Surg 1997;63:74-77.[Abstract/Free Full Text]
41. Rich J.B. The efficacy and safety of aprotinin use in cardiac surgery. Ann Thorac Surg 1998;66:S6-S11.[Abstract/Free Full Text]
42. Smith C.R., Spanier T.B. Aprotinin in deep hypothermic circulatory arrest. Ann Thorac Surg 1999;68:278-286.[Abstract/Free Full Text]
43. Avkiran M., Hearse D.J. Protection of the myocardium during global ischemia. Is crystalloid cardioplegia effective in the immature myocardium?. J Thorac Cardiovasc Surg 1989;97:220-228.[Abstract]
44. Karck M., Schnabel P.A., Kilkowski A., Schulte S., Haverich A. Adverse effects of crystalloid cardioplegia and slow cooling for protection of immature rat hearts. Ann Thorac Surg 1996;62:702-709.[Abstract/Free Full Text]
45. Buckberg G.D. Antegrade/retrograde blood cardioplegia to ensure cardioplegic distribution: operative techniques and objectives. J Cardiac Surg 1989;4:216-238.[Medline]
46. Bolling K., Kronon M., Allen B.S., et al. Myocardial protection in normal and hypoxically stressed neonatal hearts: the superiority of blood versus crystalloid cardioplegia. J Thorac Cardiovasc Surg 1997;113:994-1003.[Abstract/Free Full Text]
47. Pearl JM, Nelson DP, Wagner CJ, et al. Endothelin-1 blockade decreases post-reoxygenation ventricular dysfunction and leukocyte-mediated injury. Ann Thorac Surg (in press).
48. Drinkwater D.C., Cushen C.K., Laks H., Buckberg G.D. The use of combined antegrade-retrograde infusion of blood cardioplegic solution in pediatric patients undergoing heart operations. J Thorac Cardiovasc Surg 1992;104:1349-1355.[Abstract]
49. Gates R.N., Laks H., Drinkwater D.C., et al. The microvascular distribution of cardioplegic solution in the piglet heart. Retrograde versus antegrade delivery. J Thorac Cardiovasc Surg 1993;105:845-852.[Abstract]
50. Gates R.N., Laks H. Retrograde cardioplegia. Adv Cardiac Surg 1998;10:115-139.[Medline]
51. Riordan C.J., Randsbaek F., Storey J.H., Montgomery W.D., Santamore W.P., Austin E.H., III Inotropes in the hypoplastic left heart syndrome: effects in an animal model. Ann Thorac Surg 1996;62:83-90.[Abstract/Free Full Text]
52. Austin E.H., Santamore W.P., Barnea O. Balancing the circulation in hypoplastic left heart syndrome. J Cardiovasc Surg (Torino) 1994;35:137-139.[Medline]
53. Charpie J.R., Dekeon M.K., Goldberg C.S., Moska R.S., Boul E.L., Kulik T.J. Postoperative hemodynamics after Norwood palliation for hypoplastic left heart syndrome. Am J Cardiol 2001;87:198-202.[Medline]
54. Tweddell J.S., Hoffman G.M., Fedderly R.T., et al. Phenoxybenzamine improves systemic oxygen delivery after the Norwood procedure. Ann Thorac Surg 1999;67:161-168.[Abstract/Free Full Text]
55. Reinoso-Barbero F., Garcia-Fernandez F.J., Diez-Labajo A., del Cerro M.J., Cordovilla G. Postoperative use of milrinone for Norwood procedure. Paediatr Anaesth 1996;6:342-343.[Medline]
56. Taeed R., Nelson D.P., Pearl J.M., et al. Arterial O2 saturation alone does not predict pulmonary to systemic blood flow ratio in the post-operative Norwood patient. Crit Care Med 1999;27:A40.
57. Barnea O., Austin E.H., Richman B., Santamore W.P. Balancing the circulation: theoretic optimization of pulmonary/systemic flow ratio in hypoplastic left heart syndrome. J Am Coll Cardiol 1994;24:1376-1381.[Abstract]
58. Migliavacca F., Yates R., Pennati G., Dubini G., Fumero R., de Leval M.R. Calculating blood flow from Doppler measurements in the systemic-to-pulmonary artery shunt after the Norwood operation: a method based on computational fluid dynamics. Ultrasound Med Biol 2000;26:209-219.[Medline]
59. Schmid F.X., Kampmann C., Kuroczynski W., et al. Adjustable tourniquet to manipulate pulmonary blood flow after Norwood operations. Ann Thorac Surg 1999;68:2306-2309.[Abstract/Free Full Text]
60. Jobes D.R., Nicolson S.C., Steven J.M., Miller M., Jacobs M.L., Norwood W.I., Jr Carbon dioxide prevents pulmonary overcirculation in hypoplastic left heart syndrome. Ann Thorac Surg 1992;54:150-151.[Abstract]
61. Weldner P.W., Myers J.L., Gleason M.M., et al. The Norwood operation and subsequent Fontan operation in infants with complex congenital heart disease. J Thorac Cardiovasc Surg 1995;109:654-662.[Abstract/Free Full Text]
62. Riordan C.J., Randsbeck F., Storey J.H., Montgomery W.D., Santamore W.P., Austin E.H., III Effects of oxygen, positive end-expiratory pressure, and carbon dioxide on oxygen delivery in an animal model of the univentricular heart. J Thorac Cardiovasc Surg 1996;112:644-654.[Abstract/Free Full Text]
63. Chang A.C., Zucker H.A., Hickey P.R., et al. Pulmonary vascular resistance in infants after cardiac surgery: role of carbon dioxide and hydrogen ion. Crit Care Med 1995;23:568-574.[Medline]
64. Mosca R.S., Bove E.L., Crowley D.C., Sandhu S.K., Schork M.A., Kulik T.J. Hemodynamic characteristics of neonates following first stage palliation for hypoplastic left heart syndrome. Circulation 1995;92(9 Suppl):II267-II271.
65. Tabbutt S., Duncan B.W., McLaughlin D., Wessel D.L., Jonas R.A., Laussen P.L. Delayed sternal closure after cardiac operations in a pediatric population. J Thorac Cardiovasc Surg 1997;113:886-893.[Abstract/Free Full Text]
66. Jaggers J.J., Forbess J.M., Shah A.S., et al. Extracorporeal membrane oxygenation for infant postcardiotomy support: significance of shunt management. Ann Thorac Surg 2000;69:1476-1483.[Abstract/Free Full Text]

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