A controlled study of transesophageal echocardiography to guide central venous catheter placement in congenital heart surgery patients

Transesophageal echocardiography (TEE) and central venous catheter (CVC) placement are often used during congenital cardiac surgery. Complications of CVC placement include cardiac perforation, inadvertent arterial placement, and erroneous hemodynamic data from unrecognized malposition. In this study, we used a prospective, randomized, controlled design to evaluate the use of TEE to guide depth of insertion and confirm superior vena cava cannulation, and to improve the percentage of correctly placed CVCs and reduce complications of CVC placement. One hundred forty-five patients were studied. Eighty patients were randomized to have subclavian vein insertion, 64 to have internal jugular insertion, and 1 to have external jugular insertion of CVC. TEE-guided CVC placement resulted in 100% correct placement when assessed by preoperative TEE, versus 86% in the control group (72 of 72 vs. 63 of 73; P = 0.01). There was no difference in correct placement between the two groups when assessed by postoperative chest radiograph (81.9% TEE versus 75.3% control; P = not significant). One significant complication, a superior vena cava perforation, occurred in the control group. Time to placement was 9.6 min in the TEE group versus 8.0 min in the control group (P = 0.015).

IMPLICATIONS

Transesophageal echocardiography can be used to guide central venous catheter placement in congenital heart surgery. Central venous catheters that seem to be located high in the right atrium by chest radiograph in these patients are often actually in the superior vena cava and pose little risk of cardiac perforation.

Customized perfusion circuit for the tiny ascending aorta

Cannulating a pediatric patient with an interrupted aortic arch presents many challenges. Two cannulas are necessary to allow for proper blood flow to the head and to the extremities. This case was made more difficult by the weight of the child and the small size of the ascending aorta. The available pediatric cannulas were too large. The perfusionist adapted two 14-gauge intravenous (i.v.) catheters as arterial cannulas which were incorporated into the 1/4-inch arterial line. The 14-gauge i.v. catheters worked successfully. While on cardiopulmonary bypass, the patient was both metabolically and hemodynamically stable. The patient survived the procedure and was eventually discharged from hospital.

Evaluation of a physiologic pulsatile pump system for neonate-infant cardiopulmonary bypass support

An alternate physiologic pulsatile pump (PPP) system was designed and evaluated to produce sufficient pulsatility during neonate-infant open heart surgery. This hydraulically driven pump system has a unique "dual" pumping chamber mechanism. The first chamber is placed between the venous reservoir and oxygenator and the second chamber between the oxygenator and patient. Each chamber has two unidirectional tricuspid valves. Stroke volume (0.2-10 ml), upstroke rise time (10-350 msec), and pump rate (2-250 beats per minute [bpm]) can be adjusted independently to produce adequate pulsatility. This system has been tested in 3-kg piglets (n = 6), with a pump flow of 150 ml/kg/min, a pump rate of 150 bpm, and a pump ejection time of 110 msec. After initiation of cardiopulmonary bypass (CPB), all animals were subjected to 25 minutes of hypothermia to reduce the rectal temperatures to 18 degrees C, 60 minutes of deep hypothermic circulatory arrest (DHCA), then 10 minutes of cold perfusion with a full pump flow, and 40 minutes of rewarming. During CPB, mean arterial pressures were kept at less than 50 mm Hg. Mean extracorporeal circuit pressure (ECCP), the pressure drop of a 10 French aortic cannula, and the pulse pressure were 67+/-9, 21+/-6, and 16+/-2 mm Hg, respectively. All values are represented as mean+/-SD. No regurgitation or abnormal hemolysis has been detected during these experiments. The oxygenator had no damping effect on the quality of the pulsatility because of the dual chamber pumping mechanism. The ECCP was also significantly lower than any other known pulsatile system. We conclude that this system, with a 10 French aortic cannula and arterial filter, produces adequate pulsatility in 3 kg piglets.

In utero diagnosis of intrapericardial teratoma: a case for in utero open fetal surgery

We present a case of intrapericardial teratoma diagnosed by ultrasound at 26 weeks of gestation presenting as a large tumour mass and rapid development of hydrops fetalis. The fetus died in utero one day before scheduled open fetal surgery.

Technical considerations for valve repair in patients with congenital heart disease

Valve repair is a critical element in the surgical treatment of congenital heart disease. Growing children require a longitudinal management strategy not commonly necessary in adult cardiac surgery. The use of valve prostheses poses unique problems in children, not only due to size limitations, but also to difficulties with chronic medical management. For these reasons, considerable effort is given to repairing even severely malformed valves in pediatric patients. This article provides a brief overview of some commonly used techniques in reparative valve surgery in children.

Correction of anomalous systemic venous drainage in heterotaxy syndrome

A 3-month-old patient with heterotaxy syndrome, complex intracardiac malformations, and severe heart failure underwent surgical correction. Anatomy included an interrupted inferior vena cava with hemiazygous continuation to a persistent left superior vena cava draining to the left atrium. The presence of partial anomalous pulmonary venous drainage precluded an intraatrial baffle. Systemic venous reconstruction was achieved using the left atrial appendage along with an intracardiac repair of the other defects.

Ross-Konno procedure with interrupted aortic arch repair in a premature neonate

A 1,700-g premature baby who presented with interrupted aortic arch type B, hypoplastic aortic annulus, severe subaortic stenosis, and large ventricular septal defect underwent successful surgical repair. A Ross-Konno operation was used to address the left ventricular outflow tract obstruction, hypoplastic aortic annulus, and ventricular septal defect. The interruption was repaired with a direct anastomosis.

Peritoneal dialysis. An adjunct to pediatric postcardiotomy fluid management

Patients requiring cardiopulmonary bypass for congenital heart surgery commonly exhibit impaired renal function and extravascular fluid retention. These conditions contribute to early postoperative fluid overload, which may result in significant morbidity and mortality. We examined the safety and efficacy of peritoneal dialysis in removing extravascular fluid from critically ill postcardiotomy patients. A retrospective case review from July of 1995 through April of 1996 was conducted. All patients undergoing peritoneal dialysis achieved a net negative fluid balance. Average urine output increased from 2.1 cc/kg/hr to 3.9 cc/kg/hr (P < 0.01) during the pre-peritoneal dialysis to post-peritoneal dialysis period, and the mean number of inotropic agents decreased from 2.2 to 1.7 (P < 0.05). Controlled comparison revealed that the peritoneal dialysis cohort more rapidly achieved a negative weight-adjusted fluid balance throughout the early postoperative course. The peritoneal dialysis group's illness severity decreased more rapidly within the 24-hour period after initiation of peritoneal dialysis than did that of the control cohort over the same period of time. No difference in postoperative morbidity or mortality existed between the study groups. Complications from the catheter placement were minimal, and no patient experienced peritonitis or metabolic or hemodynamic instability during peritoneal dialysis catheter placement, usage, or removal. Peritoneal dialysis is a safe and effective form of renal replacement therapy, even among critically ill pediatric postcardiotomy patients. Early postsurgical institution of peritoneal dialysis may hasten early postoperative recovery. We speculate that intraoperative catheter placement reduces the complication rate associated with this treatment modality.

One-stage neonatal repair of complex aortic arch obstruction or interruption. Recent experience at Texas Children's Hospital

The optimal surgical approach for complex aortic coarctation or an interrupted aortic arch with associated intracardiac defects is not universally agreed upon. We reviewed our experience with 18 consecutive patients (10 with coarctation, 8 with interrupted aortic arch) undergoing a 1-stage repair through median sternotomy between September of 1995 and February of 1997. Age at operation ranged from 3 days to 3 months (mean 23 days) and weight ranged from 1,700 g to 5,100 g (mean 3,350 g). Under hypothermic circulatory arrest, the aortic arch was reconstructed using native tissue-tissue anastomoses, and coexisting intracardiac anomalies were repaired by standard techniques. All patients survived the procedure and were ultimately discharged from the hospital. There were 2 late deaths in the interrupted aortic arch group, 1 during reoperation for subaortic stenosis and the other from noncardiac causes 5 months after discharge. Another interrupted aortic arch patient required a Ross-Konno procedure 8 months later. There has been no recoarctation among the 16 survivors. Thus a 1-stage repair for complex aortic arch obstruction in neonates can be accomplished with low operative risk, although long-term outcome is strongly influenced by the presence of subaortic obstruction.

Right-to-left interatrial shunt after pneumonectomy

BACKGROUND

Platypnea and Orthodeoxia have been described with congenital heart and severe lung diseases.

METHODS

We report 4 patients in whom platypnea and orthodeoxia developed after pneumonectomy. In these patients the mean oxygen saturation on room air was 65% (range, 45% to 79%) in the supine position. On O2 therapy it improved to 94% (range, 80% to 99%). When the patients assumed the erect position and were receiving O2 therapy the saturation dropped to a mean of 76% (range, 56% to 82%) and the patients complained of shortness of breath. Cardiac catheterization revealed a mean pulmonary capillary wedge pressure of 11.6 mm Hg (range, 7 to 18 mm Hg). All patients had normal right atrial pressure. A right-to-left interatrial shunt through a patent foramen ovale was documented by transesophageal echocardiography and dynamic ultrafast magnetic resonance imaging. The patients underwent surgical closure of the patent foramen ovale.

RESULTS

In the erect position, the room air O2 saturation improved to a mean of 95% (range, 92% to 99%), and the shortness of breath disappeared.

CONCLUSIONS

Postpneumonectomy patients complaining of shortness of breath should be assessed for platypnea and orthodeoxia. A right-to-left interatrial shunt through a patent foramen ovale can occur even in the absence of elevated right heart pressures, especially after right pneumonectomy, and is accentuated in the upright posture. Surgical correction of the patent foramen ovale can produce dramatic improvement.

Modified Norwood procedure for hypoplastic left heart syndrome

BACKGROUND

Since June 1994, we have used a modification of the Norwood technique in 13 patients presenting with the hypoplastic left heart syndrome or similar variants.

METHODS

This technique involves coarctation repair, arch reconstruction, and creation of a neo-ascending aorta using autologous great vessel tissue only. Pulmonary blood flow is provided by a central shunt of 3.0- to 4.0-mm Gore-Tex.

RESULTS

The mean age and weight at operation were 15 days (range, 1 to 77 days) and 3.2 kg (range, 1.7 to 4.6 kg), respectively. The mean circulatory arrest time was 32 minutes (range, 25 to 50 minutes). There was one operative death, and there have been no late deaths. Seven patients have gone on to conversion to a bidirectional cavopulmonary shunt at a mean age of 6 months. There have been no cases of recurrent coarctation, arch obstruction, or left pulmonary artery stenosis. Significant coronary insufficiency requiring revision of the ascending aortic reconstruction has developed in 2 patients.

CONCLUSIONS

We believe this approach offers the advantage of using the patient's own native tissue for all great vessel reconstruction. This technique may also allow 10 to 15 minutes less of circulatory arrest time. The theoretic benefits include improved growth of repaired structures and avoidance of homograft or prosthetic material. The long-term results remain to be elucidated.

Surgical repair of severe bilateral branch pulmonary artery stenosis

Management options for severe, bilateral branch pulmonary artery stenosis include percutaneous balloon dilation and direct surgical correction. Results with both balloon angioplasty and operation have been somewhat unpredictable. We report a case of staged surgical correction involving bilateral branch pulmonary artery reconstruction.

Hemodynamic and physiologic changes during support with an implantable left ventricular assist device

To evaluate hemodynamic effectiveness and physiologic changes on the HeartMate 1000 IP left ventricular assist device (Thermo Cardiosystems, Inc., Woburn, Mass.), we studied 25 patients undergoing bridge to heart transplantation (35 to 63 years old, mean 50 years). All were receiving inotropic agents before left ventricular assist device implantation, 21 (84%) were supported with a balloon pump, and 7 (28%) were supported by extracorporeal membrane oxygenation. Six patients died, primarily of right ventricular dysfunction and multiple organ failure. Nineteen (76%) were rehabilitated, received a donor heart, and were discharged (100% survival after transplantation). Pretransplantation duration of support averaged 76 days (22 to 153 days). No thromboembolic events occurred in more than 1500 patient-days of support with only antiplatelet medications. Significant hemodynamic improvement was measured (before implantation to before explantation) in cardiac index (1.7 +/- 0.3 to 3.1 +/- 0.8 L/min per square meter; p < 0.001), left atrial pressure (23.7 +/- 7 to 9 +/- 7.5 mm Hg; p < 0.001), pulmonary artery pressure, pulmonary vascular resistance, and right ventricular volumes and ejection fraction. Both creatinine and blood urea nitrogen levels were significantly higher before implantation in patients who died while receiving support. Renal and liver function returned to normal before transplantation. We conclude that support with the HeartMate device improved hemodynamic and subsystem function before transplantation. Long-term support with the HeartMate device has a low risk of thromboemboli and makes a clinical trial of a portable HeartMate device a realistic alternative to medical therapy.

Airway management during bilateral sequential lung transplantation for cystic fibrosis

Bilateral sequential lung transplantation is now an accepted therapy for patients with end-stage cystic fibrosis. In our experience, the use of a standard double-lumen endotracheal tube to establish one-lung ventilation during bilateral lung transplantation has been associated with difficulty in clearing the airway of the thick, tenacious secretions characteristically seen in these patients. Intraoperatively, retained secretions have resulted in inadequate ventilation with subsequent hypercarbia, hypoxia, and the need for cardiopulmonary bypass support. We therefore changed our airway management to a single-lumen endotracheal tube combined with a bronchial blocker to establish one-lung ventilation during bilateral lung transplantation. The lumen of a single-lumen tube accommodates larger suction catheters and an adult bronchoscope, which has a larger suction port. We have used this technique in our last five transplantations, finding easier clearing of airway secretions along with markedly improved ventilation compared with management with a double-lumen tube. We recommend this technique of airway management when performing a bilateral single-lung transplantation for end-stage cystic fibrosis.

Repair of insufficient bicuspid aortic valves

A technique for the repair of bicuspid aortic valves that includes resection of the flail segment of the prolapsing leaflet, annuloplasty, and resection of the raphe, when present, has been reported. To assess the efficacy of this technique in the repair of insufficient bicuspid aortic valves, the results in 72 consecutive patients were assessed. The mean age of the patients was 39 +/- 11 years; 94% were male. Fifty-six patients (78%) underwent isolated aortic valve repair, 9 (12.5%) underwent aortic and mitral valve repair, and 7 (9.7%) had other associated procedures. All patients underwent leaflet resection, including 35 (48%) at the raphe. The mean aortic occlusion time was 39 +/- 12 minutes. There were no operative deaths. The severity of aortic insufficiency, as assessed by Doppler echocardiography (graded from 0 to 4) preoperatively and intraoperatively and at late follow-up, was 3.6 +/- 0.6, 0.4 +/- 0.4, and 0.9 +/- 0.8, respectively, with a p value of < 0.0001 for the latter two values versus the preoperative one. There have been no postoperative deaths. Patients did not receive anticoagulation treatment and there were no strokes or episodes of endocarditis. Six patients have required reoperation; 3 underwent repeat repair. The Kaplan-Meier freedom from aortic valve reoperation probabilities at 12 and 24 months were 94% and 89.5%, respectively. We conclude that valvuloplasty for insufficient bicuspid aortic valves is technically safe, is associated with a low incidence of recurrent insufficiency, and has been associated with no other valve-related complications.

Surgical techniques for aortic valvuloplasty

Since 1988, reparative techniques have been used at our institution to treat valvular insufficiency in selected patients with aortic valve disease. The limitations of aortic valve replacement are well recognized; it is this knowledge that has motivated us to find out whether a subgroup of patients who have aortic insufficiency might be candidates for preservation of their native aortic valves. This subgroup includes patients who have leaflet prolapse, perforation, or calcification. We describe our methods of patient evaluation and selection, as well as our surgical techniques for both bicuspid and tricuspid aortic valve repair.

Cervical esophago-esophageal anastomosis

We describe our results with cervical esophagoesophageal anastomosis. This approach has been used with success in 4 patients. It has the advantage of avoiding esophagectomy in patients with benign disease and allows restoration of esophageal continuity in patients having limited options for esophageal replacement.

Acute and chronic pulmonary vasoconstriction after left lung autotransplantation in conscious dogs

We investigated the acute and chronic effects of left lung autotransplantation (LLA) on the left pulmonary vascular pressure-flow (LP/Q) relationship in conscious dogs. Continuous LP/Q plots were generated in chronically instrumented conscious dogs 2 days, 2 wk, 1 mo, and 2 mo after LLA. Identically instrumented normal conscious dogs were studied at equal time points post-surgery. LLA had little or no effect on baseline systemic hemodynamics or blood gases. In contrast, compared with normal conscious dogs, striking active flow-independent pulmonary vasoconstriction was observed 2 days post-LLA. The slope of the LP/Q relationship was increased from a normal value of 0.275 +/- 0.021 to 0.699 +/- 0.137 mmHg.ml-1.min-1.kg-1 2 days post-LLA. Pulmonary vasoconstriction of similar magnitude was also observed on a chronic basis at 2 wk, 1 mo, and even 2 mo post-LLA. Pulmonary vasoconstriction post-LLA was not due to fixed resistance at the left pulmonary arterial or venous anastomotic sites. Finally, systemic arterial blood gases were unchanged when total pulmonary blood flow was directed to exclusively perfuse the transplanted left lung. Thus, LLA results in both acute and chronic pulmonary vasoconstriction in conscious dogs. LLA should serve as a useful stable experimental model to assess the specific effects of surgical transplantation on pulmonary vascular regulation.

Effects of cyclosporine on cerebral blood flow and metabolism in dogs

Neurological side effects associated with cyclosporine immunosuppressive therapy are generally believed to occur with CsA blood concentrations above the therapeutic range. The effects of high blood CsA levels on cerebral hemodynamics, metabolism, and electrophysiologic activity were studied in acute (no CsA prior treatment) and chronic (with CsA prior treatment) dogs. In acute animals, when parenteral CsA (10 mg/kg or 25 mg/kg) was administered intravenously (CsA blood level 2000-22,000 ng/ml), slight but significant time-dependent decreases in cerebral blood flow (CBF), prolongation of absolute latencies of somatosensory-evoked potential (SSEP), and brainstem auditory-evoked responses (BAER) were noted. In the CsA chronically administered animals (oral CsA 25 mg/kg/24 hr for 14 days, CsA blood level 1077 ng/ml), baseline cerebral physiologic parameters were normal, and the cerebral responses to further administration of CsA (25 mg/kg, CSA blood level 56,000 ng/ml) intravenously were similar to those of the acute animals. Animals given Cremophor EL, the solvent for parenteral CsA preparation, showed similar cerebral responses to those observed in animals given CsA. Thus this study showed that CsA, regardless of the dose given, whether chronically or acutely administered, or the solvent for CsA all induced similar cerebral physiologic responses. We suggest that the cerebral physiologic and functional changes associated with parenteral CsA administration were small and were likely caused by its solvent, Cremophor EL, rather than CsA itself. Furthermore on the basis of our results, it is unlikely that high blood CsA per se can account for neurological side effects that occur in immunosuppressed patients.