Blade and balloon atrial septostomy for left heart decompression in patients with severe ventricular dysfunction on extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is used as circulatory support or bridge to transplantation in patients with severe left ventricular (LV) dysfunction. Left heart decompression is needed to reduce pulmonary edema, prevent pulmonary hemorrhage, and reduce ventricular distention that may aid in recovery of function. We reviewed our experience from November 1993 to December 1997 with 10 patients having severe LV dysfunction (7 myocarditis, 3 dilated cardiomyopathy) who required circulatory support with ECMO and who underwent left heart decompression with blade and balloon atrial septostomy (BBAS). Patients ranged in age from 1 to 24 years (median, 3 years). Indications for BBAS included left atrial/left ventricular distension (10), pulmonary edema/hemorrhage (9), or severe mitral regurgitation (2). BBAS was performed electively in eight patients and urgently in two patients. BBAS was performed while on ECMO in seven patients and pre-ECMO in three. A femoral venous approach was used in all patients. ECMO patients were fully heparinized. Transseptal puncture was required in nine patients while one patient had a patent foramen ovale. Blade septostomy was performed in all patients. Enlargement of the defect was then performed by stationary balloon dilation in nine and Rashkind balloon atrial septostomy in one. Balloon diameters ranged from 10 to 20 mm. Sequential balloon inflations were performed in some patients. Adequacy of the atrial septal defect (ASD) was confirmed by pressure measurement and echocardiography. Adequate left heart decompression was achieved in all patients. Pulmonary edema improved in nine of nine patients. Left atrial mean pressure fell from a mean of 30.5 mm Hg, (range, 12-50 mm Hg) to 16 mm Hg (range, 9-24 mm Hg). Left atrial to right atrial pressure gradient fell from a mean of 20 mm Hg pre-BBAS to 3 mm Hg post-BBAS. ASDs ranged in size from 2.5 to 8 mm (mean, 5.9 mm). Complications included needle perforation of the left atrium without hemodynamic compromise (one), ventricular fibrillation requiring defibrillation (one), and hypotension following BBAS which responded to volume infusion (two). Duration of ECMO ranged from 41 hr to 704 hr (mean, 294 hr). Seven patients survived and four patients had recovery of normal LV function. Of those who recovered, two had no ASD at follow-up while two ASDs are patent 14 days and 3 months post-BBAS. Three patients underwent successful cardiac transplantation. Three patients died, all of whom had multisystem organ failure with or without sepsis. A patent ASD was noted at transplant (three) or autopsy (two). No patient required a second BBAS. BBAS alleviates severe left atrial hypertension and pulmonary edema. In addition, BBAS avoids the potential bleeding complications of surgical left heart decompression. Stationary balloon dilation of the atrial septum is an effective alternative to Rashkind balloon septostomy in older patients. BBAS achieves left heart decompression that may permit recovery of LV function or allow extended ECMO support as a bridge to transplant.

Prolonged extracorporeal life support for bridging to transplant: technical and mechanical considerations.

Through July 1995, the Extracorporeal Life Support Organization (ELSO) registry listed 87 patients who received extracorporeal life support (ECLS) as a bridge to cardiac transplantation with a survival rate of 41%. At Arkansas Children's Hospital, 17 patients (aged between two days and 24 years) with diagnoses of dilated cardiomyopathy (seven), postcardiotomy (seven) and acute viral myocarditis (three) were bridged with ECLS. Mechanical complications only occurred in two patients, neither of which necessitated withdrawal of ECLS. Decompression of the left heart was performed in 11 patients, six via a surgically placed vent and five with a blade/balloon artial septostomy. Documented infection occurred in 11/17 patients, but only one patient died from infection. Fifteen of 17 patients (88%) recovered or were transplanted, of which 13 (76%) were discharged home. With left-heart decompression and appropriate treatment of infection, ECLS may be used as a bridge to cardiac transplantation or until the return of cardiac function.

Extracorporeal life support of neonates with congenital cardiac defects: techniques used during cardiac catheterization and surgery.

Neonatal patients with congenital cardiac defects require proper diagnosis often by cardiac catheterization before surgical repair. In our institution, patients whose echocardiograms reveal surgically correctable lesions, but who are severely decompensated, have been placed on Extracorporeal Life Support (ECLS) prior to catheterization or surgery. Subsequent management of ECLS and cardiopulmonary bypass (CPB) are dictated by the surgical procedure. Hypothermia can be utilized while on ECLS to facilitate low-flow CPB, or circulatory arrest. Total extracorporeal circulation may be performed with the ECLS circuit, or the patient may be transferred to a conventional CPB circuit during the procedure. If required, post surgical ECLS can be facilitated through prior cannulation. We have found pre-operative institution of ECLS, in the neonate with severe congenital cardiac defects, provides immediate control of hemodynamic and respiratory problems, lowers the risk of cardiac catheterization, and reduces the usage of blood products during surgery.

Thromboembolism in patients undergoing thoracotomy.

To determine the incidence of thromboembolism in relation to thoracotomy, 77 patients undergoing pulmonary resection were prospectively studied up to 30 days postoperatively for deep venous thrombosis and pulmonary embolism. Overall, 20 of 77 patients (26%) had thromboembolic events during their hospitalization. Four deep venous thromboses and 1 pulmonary embolism were detected in 5 of 77 patients preoperatively for an incidence of 6%. Postoperative thromboembolism was detected in 15 of 77 (19%): deep venous thrombosis in 11 (14%) and pulmonary embolism in 4 (5%). No postoperative thromboembolisms occurred in the 17 patients receiving preoperative aspirin or ibuprofen, whereas they did occur in 25% of the remainder (15/60). Thromboembolism after pulmonary resection was more frequent with bronchogenic carcinoma than with metastatic cancer or benign disease (15/59 [25%] versus 0/18 [0%]; p < 0.01), adenocarcinoma compared with other types of carcinoma (11/25 [44%] versus 4/34 [12%]; p < 0.0004), large primary lung cancer (> 3 cm in diameter) compared with smaller lesions (9/19 [47%] versus 6/40 [15%]; p < 0.0001), stage II compared with stage I (7/14 [50%] versus 7/34 [21%]; p < 0.04), and pneumonectomy or lobectomy compared with segmentectomy and wedge resection (14/49 [29%] versus 1/28 [4%]; p < 0.005). Three of 4 patients with thromboembolism detected preoperatively had operation within the previous year. Postoperative pulmonary embolism was fatal in 1 of 4 (25%) and accounted for the one death. These results suggest patients undergoing thoracotomy for lung cancer, especially adenocarcinoma, should be considered for thromboembolic prophylaxis.

Mobile extracorporeal membrane oxygenation.

Transport of critically ill neonates in need of extracorporeal membrane oxygenation can be risky. Their extreme cardiorespiratory instability may delay or even preclude conventional transport to an extracorporeal membrane oxygenation center. We report the use of a UH-1 helicopter specially adapted for mobile extracorporeal membrane oxygenation support to transport a critically ill neonate.

Extracorporeal membrane oxygenation for cardiac failure after congenital heart operation.

Despite continuing improvement in myocardial protection and surgical technique, the repair of complex congenital heart lesions can result in cardiopulmonary compromise refractory to conventional therapy. In a 29-month period, 24 patients (aged 14 hours to 6 years) were treated with extracorporeal membrane oxygenation (ECMO) 28 times for profound cardiopulmonary failure. Four patients required ECMO after each of two cardiopulmonary bypass procedures. Seventeen patients required ECMO to be initiated in the operating room: 12 (71%) were weaned successfully from ECMO, and 8 (47%) survived. Seven patients had ECMO initiated in the intensive care unit: 6 (86%) were weaned, and 5 (71%) survived. Serial echocardiograms demonstrated substantial recovery of cardiac function in 18 of 21 instances (86%) of ventricular failure from myocardial dysfunction. Overall, 18 of 24 patients (75%) were successfully weaned from ECMO including all 4 who underwent 2 ECMO treatments. We conclude that ECMO can successfully salvage children who have serious cardiopulmonary failure immediately after a congenital heart operation and that long-term survival is possible after two ECMO treatments.

Evaluation of the reconstructed carotid artery following extracorporeal membrane oxygenation.

Over a 12-month period, 28 neonatal patients in respiratory failure were supported with extracorporeal membrane oxygenation (ECMO), and 11 of these underwent successful repair of the right carotid artery post-ECMO. Nine of 11 were studied with duplex color-flow Doppler imaging between 14 and 109 days of age and again at 1 year of age. A velocity ratio (A/B) of the peak systolic velocity above the level of the anastomosis to the peak systolic velocity below the anastomosis was measured to assess the degree of stenosis, if any, at the repair site. Antegrade flow through the carotid was detected post-ECMO in 8 of 9 infants, and antegrade and retrograde flow was documented in 1 infant. A/B ratios ranged from 1.00 to 8.60 (A/B ratio of 1 is normal; 2.0 indicates at least a 50% obstruction to flow). Four of 9 patients had ratios greater than 2.0, and 8 of 9 exhibited some evidence of obstruction. Follow-up scans were performed on 8 of 9 infants between 12 and 18 months of age. All infants examined showed marked improvement in A/B ratio and patency of the vessel, documenting that initial narrowing of the vessel is reversible. No infant had evidence of embolic phenomena to the right side of the brain by magnetic resonance imaging. Repair of the common carotid artery post-ECMO is technically feasible without increasing the risk of brain injury.

Omental pedicle grafting in the treatment of postcardiotomy sternotomy infection.

Postcardiotomy sternal infection occurred in 20 (2%) of 1007 patients undergoing cardiac surgery between September 1985 and December 1987, a 10-fold increase over the preceding 33 months (4 [0.24%] of 1627 patients). Cultures were sterile in 5 patients and yielded staphylococci in 12 and a variety of bowel organisms in 3. The cause for the increased occurrence of sternal wound infection is unclear after multivariate analysis, although infections have precipitously dropped subsequent to changing to cefuroxime sodium antibiotic prophylaxis. Treatment has evolved to appropriate antibiotics and early débridement of involved sternum and cartilage. Rewiring the sternum is not attempted. If gross purulence is not present, primary closure is accomplished using muscle flaps (2 patients) or omental pedicle grafts (17 patients). In the presence of gross purulence, the wound is packed open for 5 days and then closed in the above fashion. Two patients required skin grafts for primary closure. The omental pedicle flap is preferred due to simplicity and improved coverage of the sternal defect inferiorly. Nineteen patients healed primarily. A superficial wound infection was drained in 1 patient. Midline incisional hernias developed in 3 muscular patients. Omentum is now harvested through a left subcostal incision. Hospital stay was under 2 weeks in 13 patients. One death occurred due to multisystem failure prior to completion of wound closure. In our experience, early sternal débridement and omental pedicle grafting with primary closure is appropriate therapy for postcardiotomy sternotomy infections. The presence of gross purulence may require 5 days of open packing prior to omental grafting. No significant complications occurred, and mortality was low. A left subcostal incision for omental harvesting is utilized to avoid the occurrence of delayed incisional hernias.

Internal banding for palliation of truncus arteriosus in the neonate.

A method for surgically limiting pulmonary blood flow in the critically ill neonate with truncus arteriosus is described. Two recent cases utilizing this technique are presented. Comparisons are made between this and other palliative surgical procedures used in truncus arteriosus.

Effect of nuclear magnetic resonance on chromosomes of mouse bone marrow cells.

Three groups of six male Balb/c mice, subjected to 30 MHz continuous wave NMR exposure in a static magnetic field of 7.05 K Gauss for one hour, were each compared to another group of ten unexposed mice with respect to chromatid and chromosomal aberrations. The exposed groups were sacrificed at two hours, 24 hours and 48 hours following NMR exposure respectively. Control mice were sacrificed 24 hours after sham-exposure. All groups had approximately 0.02 apparent aberrations per cell. These apparent aberrations were in the form of metacentric chromosomes, possibly resulting from a union of chromosomes at their centromeres or possibly simply chromosomes in association. The results are consistent with earlier in vitro findings that NMR exposure causes no adverse cytogenetic effects.

Development and evaluation of pulsatile roller pump and tubing for cardiac assistance.

In our laboratories we have developed a roller pump for cardiopulmonary bypass and circulatory assistance that has the ability to produce steady or pulsatile flow. The pulsatile mode can also be used for counterpulsation. The roller pump has been tested both experimentally and clinically. Studies have also been performed in vitro and in vivo to evaluate and select the best medical-grade roller pump tubing to be used in the pump for short- and long-term support. In vitro tests included rebounding of tubing volume versus revolutions per minute, rebounding over time with continuous pumping, flex life, and spallation. In vivo testing was performed in mongrel dogs using heparinless left heart bypass pumping for 6 h. Hematologic studies were performed during the procedure. Postmortem examination was performed, looking especially for thromboembolism. The tubing and connectors were also inspected. The results of the in vivo and in vitro tests of all tubings were then compared.