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Biomedical subjects

Charles D Fraser

Publications and source records attributed to Charles D Fraser.

At least 37 records · Page 2Linked to original sources

Lessons learned from the first application of the DeBakey VAD Child: an intracorporeal ventricular assist device for children.

We report and describe the design and the first clinical implantation of the DeBakey ventricular assist device (VAD) Child, a pediatric intracorporeal left ventricular assist device, in a 6-year-old girl. The risk-benefit of novel technologies in advanced heart failure and the lessons learned by our experience are important to consider in hopes that other centers (where this device is now available) may benefit.

Cardiomyopathies↗

Anesthetic management and outcome of complex late arterial-switch operations for patients with transposition of the great arteries and a systemic right ventricle.

OBJECTIVE: For patients with transposition of the great arteries and a systemic right ventricle, complex late arterial-switch operations (double switch, switch conversion, Senning-Rastelli) after the newborn period have been described recently to restore the morphologic left ventricle to the systemic circulation. The purpose of this study was to describe the anesthetic management and perioperative outcome of this group of patients and to compare them with a control group of patients who had primary arterial-switch operations in the neonatal period. DESIGN: Retrospective database and medical record review with 3:1 control:case ratio. SETTING: Tertiary care academic children's hospital. PARTICIPANTS: Patients undergoing complex late-arterial switch operations after the newborn period. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thirteen patients were identified in the complex late-switch group and 43 in neonatal arterial-switch group. There were no perioperative deaths, no new gross neurologic deficits, and all patients were discharged home in both groups. Anesthetic and bypass times were significantly longer in the late-switch group (745 v 558 minutes, p < 0.001, and 382 v 243 minutes, p < 0.001, respectively). Transfusion requirements were similar between the groups. The incidence of arrhythmia (92% v 9%, p < 0.001), use of pacing systems (69% v 9%, p < 0.001), cardioversion (15% v 0%, p = 0.05), and pharmacologic treatment of arrhythmias (69% v 0%, p < 0.01) intraoperatively were significantly higher in the complex late-switch group. CONCLUSIONS: Patients presenting for complex late corrective operations for transposition of the great arteries require long and complex anesthetics. Despite these challenges, perioperative outcomes are excellent.

Adolescent↗

Hemodynamic effects of rescue protocol hydrocortisone in neonates with low cardiac output syndrome after cardiac surgery.

OBJECTIVE: To assess the hemodynamic effects and safety of hydrocortisone in neonates with low cardiac output syndrome requiring high levels of inotropic support and fluid resuscitation after cardiac surgery. DESIGN: Retrospective chart review. SETTING: Fifteen-bed pediatric cardiovascular intensive care unit. PATIENTS: Twelve neonates with low cardiac output syndrome after cardiac surgery to whom hydrocortisone was administered according to one of two dosing regimens (100 mg/[m.day] for 2 days, 50 mg/[m.day] for 2 days, and 25 mg/[m.day] for 1 day or 100 mg/[m.day] for 1 day, 50 mg/[m.day] for 2 days, and 25 mg/[m.day] for 2 days) were identified from the Department of Pharmacy database between September 2002 and January 2004. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The mean and systolic blood pressure increased significantly 3 hrs after hydrocortisone treatment from the values preceding hydrocortisone administration. The mean blood pressure increased from 44.0+/-3.0 to 55.4+/-2.3 mm Hg (p=.01) and the systolic blood pressure increased from 64.2+/-4.7 to 78.3+/-3.4 mm Hg (p=.04). Comparable beneficial changes were also seen in the heart rate, which decreased from 168.3+/-4.6 to 148.3+/-5.6 beats/min (p=.004) after 24 hrs of hydrocortisone administration and remained at this level during the 72 hrs of follow-up. Significant weaning of epinephrine infusions was possible, from a mean dose of 0.16 to 0.06 microg/(kg.min) (p=.008), within 24 hrs after the initiation of steroid administration, and this reduction was not offset by increases in other inotropic agents. hydrocortisone administration caused nonsignificant increases in mean blood glucose concentration (from 116.2+/-20.6 to 156.0+/-25.6 mg/dL; p=.64), mean white blood cell count (from 16.6+/-1.6 to 18.9+/-2.6 x 10 U/L; p=.35), and sodium level (from 144.7+/-1.3 to 145.3+/-1.3 mmol/L; p=.51). Ten of the 12 patients (83.3%) survived. CONCLUSION: Most of the hemodynamically compromised neonates who were unresponsive to high doses of inotropic agents and fluid resuscitation after heart surgery responded to hydrocortisone with improvement of hemodynamic parameters and a decrease in inotropic requirements.

Anti-Inflammatory Agents↗

A noninvasive estimation of mixed venous oxygen saturation using near-infrared spectroscopy by cerebral oximetry in pediatric cardiac surgery patients.

BACKGROUND: Near-infrared spectroscopy (NIRS) is a noninvasive optical monitor of regional cerebral oxygen saturation (rSO2). The aim of this study was to validate the use of NIRS by cerebral oximetry in estimating invasively measured mixed venous oxygen saturation (SvO2) in pediatric postoperative cardiac surgery patients. METHODS: Twenty patients were enrolled following cardiac surgery with intraoperative placement of a pulmonary artery (PA) or superior vena cava (SVC) catheter. Five patients underwent complete biventricular repair--complete atrioventricular canal (n=3) and other (n=2). Fifteen patients with functional single ventricle underwent palliative procedures--bidirectional Glenn (n=11) and Fontan (n=4). Cerebral rSO2 was monitored via NIRS (INVOS 5100) during cardiac surgery and 6 h postoperatively. SvO2 was measured from blood samples obtained via an indwelling PA or SVC catheter and simultaneously correlated with rSO2 by NIRS at five time periods: in the operating room after weaning from cardiopulmonary bypass, after sternal closure, and in the CICU at 2, 4, and 6 h after admission. RESULTS: Each patient had five measurements (total=100 comparisons). SvO2 obtained via an indwelling PA or SVC catheter for all patients correlated with rSO2 obtained via NIRS: Pearson's correlation coefficient of 0.67 (P<0.0001) and linear regression of r2=0.45 (P<0.0001). Separate linear regression of the complete biventricular repairs demonstrated an r=0.71, r2=0.50 (P<0.0001). Bland-Altman analysis showed a bias of +3.3% with a precision of 16.6% for rSO2 as a predictor of SvO2 for all patients. Cerebral rSO2 was a more accurate predictor of SvO2 in the biventricular repair patients (bias -0.3, precision 11.8%), compared with the bidirectional Glenn and Fontan patients. CONCLUSIONS: Regional cerebral oximetry via NIRS correlates with SvO2 obtained via invasive monitoring. However, the wide limits of agreement suggest that it may not be possible to predict absolute values of SvO2 for any given patient based solely on the noninvasive measurement of rSO2. Near-infrared spectroscopy, using the INVOS 5100 cerebral oximeter, could potentially be used to indicate trends in SVO2, but more studies needs to be performed under varying clinical conditions.

Brain Chemistry↗

Comparison of hollow-fiber membrane oxygenators in terms of pressure drop of the membranes during normothermic and hypothermic cardiopulmonary bypass in neonates.

UNLABELLED: The objective of this study was to investigate the effects of two hollow-fiber membrane oxygenators, the Capiox SX10 and the Lilliput 901, on pressure drop of the membranes during normothermic and hypothermic cardiopulmonary bypass (CPB) in neonates. METHODS: Twenty-six congenital heart surgery patients (n = 13 in each group) with a mean weight of 3 kg were included in this study. Pressure drops of the membranes, pre- and post-oxygenator extracorporeal circuit pressures (ECC) were recorded during normothermic CPB, hypothermic CPB (20 degrees C) and after rewarming. There were no differences between the groups in mean arterial pressure, pump flow rate, temperature, duration of CPB, crossclamp time or the severity of the surgical repairs. RESULTS: Pressure drop of the Capiox SX10 oxygenator was significantly lower during normothermic (32 +/- 10 versus 55 +/- 16 mmHg, p < 0.001), hypothermic (38 +/- 15 versus 72 +/- 18 mmHg, p < 0.001) and post-rewarming (42 +/- 13 versus 72 +/- 21 mmHg, p < 0.001) periods compared to the Lilliput oxygenator. In the Capiox group, the pre-oxygenator ECC pressure was also significantly lower during normothermic CPB (142 +/- 27 versus 184 +/- 43 mmHg, p < 0.01), hypothermic CPB (162 +/- 30 versus 199 +/- 38 mmHg, p < 0.01) and after rewarming periods (172 +/- 32 versus 212 +/- 42 mmHg, p < 0.01). Post-oxygenator pressures in the Capiox group were also lower than in the Lilliput group, but results were not statistically significant. CONCLUSIONS: These results suggest that the Capiox SX10 hollow-fiber membrane oxygenator produced significantly lower membrane pressure drops and pre- and post-oxygenator ECC during normothermic and hypothermic CPB. Thus, blood trauma with the Capiox during extracorporeal circulation may be significantly lower compared to the Lilliput. Further studies, including the level of complements, platelets, neutrophils and cytokines, with these oxygenators are warranted.

Blood Flow Velocity↗

Preterm infants with congenital heart disease and bronchopulmonary dysplasia: postoperative course and outcome after cardiac surgery.

OBJECTIVE: Success in treatment of premature infants has resulted in increased numbers of neonates who have bronchopulmonary dysplasia (BPD) and require surgical palliation or repair of congenital heart disease (CHD). We sought to investigate the impact of BPD on children with CHD after heart surgery. METHODS: This was a retrospective, multicenter study of patients who had BPD, defined as being oxygen dependent at 28 days of age with radiographic changes, and CHD and had cardiac surgery (excluding arterial duct ligation) between January 1991 and January 2002. Forty-three infants underwent a total of 52 cardiac operations. The median gestational age at birth was 28 weeks (range: 23-35 weeks), birth weight was 1460 g (range: 431-2500 g), and age at surgery was 2.7 months (range: 1.0-11.6 months). Diagnoses included left-to-right shunts (n = 15), conotruncal abnormalities (n = 13), arch obstruction (n = 6), univentricular hearts (n = 4), semilunar valve obstruction (n = 3), Shone syndrome (n = 1), and cor triatriatum (n = 1). RESULTS: Thirty-day survival was 84% with 6 early and 6 late postoperative deaths. Survival to hospital discharge was 68%. There was 50% mortality for patients with univentricular hearts and severe BPD. The median duration of preoperative ventilation was 76 days (range: 2-244 days) and of postoperative ventilation was 15 days (range: 1-141 days). The median duration of cardiac ICU stay was 7.5 days (range: 1-30 days) and of hospital stay was 115 days (range: 35-475 days). Current pulmonary status includes on room air (n = 14), O2 at home (n = 4), and ventilated at home (n = 4) or in hospital (n = 4), and 5 patients were lost to follow-up. CONCLUSIONS: BPD has significant implications for children who have CHD and undergo cardiac surgery, leading to prolonged ICU and hospital stays, although most survivors are not O2 dependent. Postoperative mortality was highest among patients with univentricular hearts and severe BPD. Optimal timing of surgery and strategies to improve outcome remains to be delineated.

Bronchopulmonary Dysplasia↗

Incomplete double aortic arch with atresia of the distal left arch: distinctive imaging appearance.

OBJECTIVE: We present 10 patients with double aortic arch with atresia of the distal left arch segment, a form of incomplete double aortic arch, and describe the distinct MRI and CT findings for this potentially symptomatic vascular ring. CONCLUSION: Knowledge of the distinctive imaging appearance of this congenital arch anomaly can direct the radiologist to the correct preoperative diagnosis.

Adolescent↗

Improved early results with the Fontan operation in adults with functional single ventricle.

BACKGROUND: A growing number of adults with functional single ventricles are presenting as candidates for first-time and redo-Fontan operations. This study describes the clinical presentation and early operative results of adults who have undergone Fontan modifications. METHODS: Between July 1995 and April 2003, 23 patients (>18 years old) had Fontan operations. We retrospectively reviewed their perioperative courses. RESULTS: Twenty-three Fontan operations (first-time [n = 8] and redo [n = 15]) were performed with no early or late deaths. No patient has required reoperation. One patient has been listed for orthotopic heart transplantation. The overall mean age is 23 years (18 to 41 years); mean follow-up, 30 months; median postoperative hospital stay, 8 days (4 to 34 days); and median duration of chest tube drainage, 4 days (2 to 12 days). The postoperative New York Heart Association (NYHA) functional class was improved in 22 of 23 patients. Eight first-time Fontan operations (7 of 8 nonfenestrated) were performed; lateral tunnel (n = 7) and extracardiac conduit (n = 1). Two patients had preoperative arrhythmias. New onset arrhythmias (ventricular tachycardia and sinus node dysfunction), requiring treatment, occurred in two patients. Fifteen redo-Fontan operations (all nonfenestrated) were performed; lateral tunnel (n = 5) and extracardiac conduit (n = 10). Fifteen patients had preoperative arrhythmias, thirteen of which had intraatrial reentry tachycardia (IART) and required antiarrhythmic medications. Concomitant intraoperative radiofrequency ablation (RFA) (n = 11) and cryoablation (n = 1) procedures were performed. In the immediate postoperative period, there was IART recurrence in five patients (post-RFA [n = 4] and postcryoablation [n = 1]). At latest follow-up, no patient is being treated with antiarrhythmic medications. Two patients had new onset atrial arrhythmias that required treatment. CONCLUSIONS: The Fontan operation can be performed in adults with minimal morbidity and improved NYHA functional class. New onset arrhythmias requiring treatment are sources of perioperative morbidity. Complete arrhythmia resolution of the preoperative arrhythmia may not be achieved in the immediate postoperative period in redo-Fontan patients. However, modification (intraoperative radiofrequency ablation-right atrial debulking) of the atrial tachycardia circuits in the redo-Fontan patients can result in complete resolution of preoperative atrial tachyarrhythmias at early follow-up.

Adolescent↗

Anatomic reconstruction for recurrent aortic obstruction in infants and children.

BACKGROUND: Patients undergoing operative repair of aortic obstruction are at a lifelong risk of recurrent obstruction, and there is controversy regarding the optimal surgical technique. We have used an alternative strategy for recurrent aortic obstruction, typically involving anatomic reconstruction by means of a median sternotomy, and describe our techniques and results. METHODS: Twenty-one patients presented with recurrent aortic arch obstruction. Mean age and weight were 7.8 +/- 5.4 years (range, 0.21 to 15.2 years) and 30.6 +/- 21.8 kg (range, 3.6 to 90 kg), respectively. Recurrence involved the aortic arch to some degree in each case, as the mean preoperative transverse aortic arch z score was -2.9 +/- 1.6 (range, -7.0 to 0.1). Thoracotomy was possible in 2 patients, using re-resection with end-to-end anastomosis (n = 1) and patch aortoplasty (n = 1). The remaining 19 patients required median sternotomy, cardiopulmonary bypass, and deep hypothermic circulatory arrest for complete relief of obstruction by aortic arch advancement (n = 10), patch aortoplasty (n = 8), or interposition grafting (n = 1). RESULTS: There was 1 hospital death. Invasive blood pressure monitoring revealed no residual arm-to-leg gradient in 19 patients and a 20-mm Hg gradient in 2 patients. There have been no late deaths. No patients have undergone subsequent aortic intervention, and all are asymptomatic up to 85 months postoperatively. Two patients are currently followed with a 10-mm Hg arm-to-leg blood pressure gradient. CONCLUSIONS: Anatomic reconstruction for recurrent aortic obstruction can be safely accomplished in the majority of patients. We favor median sternotomy because of the ability of establishing cardiopulmonary bypass, the facility of anatomic reconstruction techniques, and the ability to repair concomitant cardiovascular lesions.

Adolescent↗

Left ventricular inflow obstruction associated with persistent left superior vena cava and dilated coronary sinus.

BACKGROUND: It has previously been suggested that significant dilatation of the coronary sinus can contribute to left ventricular inflow obstruction and is amenable to surgical correction. The purpose of this study was to review our experience with this rare condition. METHODS: Since 1995, 6 patients have undergone coronary sinus reduction for concerns of obstruction with other concomitant intracardiac repairs. Preoperative echocardiography identified a significantly dilated left superior vena cava to the coronary sinus in 5 patients (83%) and an abnormal mitral valve in 4 patients (67%); these resulted in abnormal Doppler inflow patterns. Preoperative cardiac catheterization was performed in 5 patients and revealed increased atrial "a" waves, with a gradient to the left ventricular end-diastolic pressure in each case. At the time of surgery, coronary sinus angioplasty was performed in all patients. RESULTS: There were no deaths, and there was no major morbidity. Follow-up imaging revealed no significant left ventricular inflow obstruction in any patient. CONCLUSIONS: We conclude that dilatation of the coronary sinus can become hemodynamically significant and that coronary sinus angioplasty is a safe and effective technique.

Adolescent↗

The Warden procedure for partially anomalous pulmonary venous connection to the superior caval vein.

PURPOSE: When there is partially anomalous pulmonary venous connection to the superior caval vein, intracardiac repair alone can result in obstruction. Although the Warden procedure involving translocation of the superior caval vein is commonly performed as an alternative to atriocavoplasty, follow-up of a larger number of patients in the modern era is lacking. We report and discuss the experience of a single institution with the Warden procedure for correction of partially anomalous pulmonary venous connection to the superior caval vein. METHODS: Since 1995, all 16 patients presenting with partially anomalous pulmonary venous connection to the superior caval vein underwent the Warden procedure at a mean age of 7.1 +/- 4.2 years, with a range from 0.2 to 14.3 years, and a mean weight of 24.7 +/- 14.0 kg, with a range from 4.1 to 52.9 kg. There were 9 males and 7 females. In 8 patients, we performed 10 concomitant procedures, including closure of an atrial or ventricular septal defect in 7, and advancement of the aortic arch in the other. RESULTS: There were no deaths, and only one episode of postoperative sinus bradycardia with intermittent junctional rhythm, which resolved spontaneously during temporary atrial pacing. All patients were discharged home in normal sinus rhythm at an average of 4.1 +/- 2.2 days after the procedure, with a range from 2 to 10 days. All are currently in the first grade of the New York Heart Association up to 5.6 years postoperatively. There is currently no evidence of sinus nodal dysfunction, nor obstruction of the superior caval vein, in any patient. CONCLUSION: The Warden procedure for partially anomalous pulmonary venous connection to the superior caval vein produces excellent results, preserves the function of the sinus node, and should be routinely considered for the repair of this lesion.

Adolescent↗

The hemi-Mustard, bi-directional Glenn, and Rastelli operations used for correction of congenitally corrected transposition, achieving a "ventricle and a half " repair.

Based on experience in several centers, the double switch operation has reportedly become the standard surgical therapy for congenitally corrected transposition. We report and discuss here the use of a "ventricle and a half" double switch operation performed due to the concerns raised intraoperatively because of the size of the morphologically right ventricle. Although the long-term course of such a procedure in this setting remains unknown, we submit that the proposed benefits of the double switch operation, even when used in the "ventricle and a half" configuration, may be superior to the alternatives.

Adolescent↗

Neurologic monitoring for special cardiopulmonary bypass techniques.

Low flow hypothermic cardiopulmonary bypass, deep hypothermic circulatory arrest, and regional low-flow cerebral perfusion are special techniques used to facilitate complex intracardiac and aortic surgery in neonates and infants. Each carries a risk of cerebral hypoxia and neurologic morbidity. Neurologic monitoring in the form of near-infrared spectroscopy for cerebral oxygenation, transcranial Doppler ultrasound, and the bispectral index electroencephalogram can monitor the brain during these techniques to determine the minimum acceptable bypass flow rates or maximum acceptable duration of deep hypothermic circulatory arrest. The use of this monitoring has the potential to improve long-term neurologic and developmental outcome.

Cardiopulmonary Bypass↗

Current expectations for newborns undergoing the arterial switch operation.

BACKGROUND: The arterial switch operation (ASO) represents a remarkable success story in the surgical treatment of cyanotic congenital heart disease. This study is designed to assess recent outcomes after the ASO in babies presenting with transposition of the great arteries (TGA) and Taussig-Bing anomaly (TBA). METHODS: One hundred twenty-five consecutive neonatal and infant ASOs were performed by 2 surgeons at Texas Children's Hospital between July 1, 1995 and October 1, 2003. Patients with TGA and TBA were offered ASO irrespective of patient size and associated cardiac malformations. Primary cardiac diagnoses included TGA with intact ventricular septum (TGA/IVS, n = 79, 63%), TGA with ventricular septal defect (TGA/VSD, n = 37, 30%), and Taussig Bing Anomaly (TBA, n = 9, 7%). RESULTS: With complete follow-up, we observed a 30-day mortality rate of 1.6% (n = 2) with 2 late deaths (1.6%), for an overall actuarial survival rate of 96.3% at 7 years. Although there was a significant incidence of complex coronary ostial origin and branching including single coronary (n = 8, 6.4%) and intramural coronary artery (n = 8, 6.4%), this was not associated with increased operative risk. All patients are fully saturated and NYHA functional class I at latest clinic visit (0.3 to 88.4 months postoperatively). There have been no late coronary events. Of 121 survivors, 7 patients (5.8%) have required cardiovascular reoperation at an average of 15.3 +/-11.7 months postoperatively (range, 3.6 to 30.6 months) for an actuarial freedom from reoperation of 90% at 7 years. CONCLUSIONS: Using current methodologies, the ASO can be performed safely and with a low incidence of need for reoperation on intermediate follow-up. Recent experience indicates operative survival rates approaching 100%.

Cardiac Surgical Procedures↗

Outcomes of congenital heart surgery patients after extracorporeal life support at Texas Children's Hospital.

The objective of this study was to investigate the outcomes of children with heart failure of various etiologies requiring temporary use of currently available technology in the U.S.A. after extracorporeal life support (ECLS) [left ventricular assist device (LVAD) or extracorporeal membrane oxygenation (ECMO)] at Texas Children's Hospital. Between July of 1995 and October of 2002, 2847 patients underwent congenital heart surgical repairs with the aid of cardiopulmonary bypass at Texas Children's Hospital. During this period, 17 patients required chronic mechanical circulatory assistance with Biomedicus centrifugal pump (n=8) or Thoratec LVAD (n=4), and ECMO (n=5). Six out of 17 patients required ECLS for postcardiotomy heart failure. Seven of the 17 patients had congenital heart disease, six had cardiomyopathy, three had late acute rejection following heart transplantation, and one had myocardial infarction. Twelve patients survived and five patients expired. Six of 12 survivors recovered sufficient cardiac function to allow device removal; and the remaining six patients underwent heart transplantation. Three out of five deaths were ECMO patients. The need for ECLS following repair of congenital heart disease is extremely rare in our institution. The requirement for the use of ECMO confers a significantly higher mortality presumably because of associated combined cardiopulmonary failure. Congenital heart disease appears to be associated with significantly higher mortality.

Adolescent↗

Changes in respiratory mechanics among infants undergoing heart surgery.

UNLABELLED: Children with excessive pulmonary blood flow (PBF) from congenital heart disease have abnormal respiratory mechanics. Exposure to hypothermic cardiopulmonary bypass (CPB) adversely affects lung function. We designed this study of 106 patients to determine the changes in respiratory mechanics in infants younger than 1 yr undergoing heart surgery. Dynamic respiratory compliance (Cdyn) and total respiratory resistance (Rrs) were measured before surgical incision, after sternal closure in the operating room, and after arrival in the intensive care unit. The following data were recorded: age, weight, preoperative pulmonary infiltrates, preoperative mechanical ventilation, evidence of increased PBF before surgery, duration of CPB, duration of aortic cross-clamp, duration of deep hypothermic circulatory arrest, use of steroids, and volume of ultrafiltrate removed. Repeated-measures analysis of variance with covariate analysis was used to determine the effect of each covariate on Cdyn and Rrs at the three time periods. Rrs improved after cardiac surgery correcting increases in PBF, and this was most pronounced in neonates. Among infants with normal or reduced PBF, cardiac surgery with CPB led to a reduction in Cdyn. We consider that the benefits of surgical correction of pulmonary overcirculation outweigh the negative effects of CPB on respiratory mechanics. IMPLICATIONS: The benefits of surgical correction of pulmonary overcirculation outweigh the negative effects of cardiopulmonary bypass on respiratory mechanics in infants.

Aging↗