E. Dean McKenzie

Brain immaturity is associated with brain injury before and after neonatal cardiac surgery with high-flow bypass and cerebral oxygenation monitoring

BACKGROUND New intraparenchymal brain injury on magnetic resonance imaging is observed in 36% to 73% of neonates after cardiac surgery with cardiopulmonary bypass. Brain immaturity in this population is common. We performed brain magnetic resonance imaging before and after neonatal cardiac surgery, using a high-flow cardiopulmonary bypass protocol, hypothesizing that brain injury on magnetic resonance imaging would be associated with brain immaturity. METHODS Cardiopulmonary bypass protocol included 150 mL . kg(-1) . min(-1) flows, pH stat management, hematocrit > 30%, and high-flow antegrade cerebral perfusion. Regional brain oxygen saturation was monitored, with a treatment protocol for regional brain oxygen saturation < 50%. Brain magnetic resonance imaging, consisting of T1-, T2-, and diffusion-weighted imaging, and magnetic resonance spectroscopy were performed preoperatively, 7 days postoperatively, and at age 3 to 6 months. RESULTS Twenty-four of 67 patients (36%) had new postoperative white matter injury, infarction, or hemorrhage, and 16% had new white matter injury. Associations with preoperative brain injury included low brain maturity score (P = .002). Postoperative white matter injury was associated with single-ventricle diagnosis (P = .02), preoperative white matter injury (P < .001), and low brain maturity score (P = .05). Low brain maturity score was also associated with more severe postoperative brain injury (P = .01). Forty-five patients had a third scan, with a 27% incidence of new minor lesions, but 58% of previous lesions had partially or completely resolved. CONCLUSIONS We observed a significant incidence of both pre- and postoperative magnetic resonance imaging abnormality and an association with brain immaturity. Many lesions resolved in the first 6 months after surgery. Timing of delivery and surgery with bypass could affect the risk of brain injury.

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.

Innovative techniques for placement of implantable cardioverter- defibrillator leads in patients with limited venous access to the heart

Background: Because of venous occlusion, intracardiac shunting, previous surgery, or small size placement of implantable cardioverter‐defibrillator (ICD) leads may not be possible using traditional methods. The purpose of this study was to evaluate and describe innovative methods of placing ICD leads.

Cardiovascular effects of sevoflurane, isoflurane, halothane, and fentanyl-midazolam in children with congenital heart disease: an echocardiographic study of myocardial contractility and hemodynamics.

BackgroundThe cardiovascular effects of halogenated anesthetic agents in children with normal hearts have been studied, but data in children with cardiac disease are limited. This study compared the effects of halothane, isoflurane, sevoflurane, and fentanyl–midazolam on systemic and pulmonary hemodynamics and myocardial contractility in patients with congenital heart disease. MethodsFifty-four patients younger than age 14 scheduled to undergo congenital heart surgery were randomized to receive halothane, sevoflurane, isoflurane, or fentanyl–midazolam. Cardiovascular and echocardiographic data were recorded at baseline and at randomly ordered 1 and 1.5 minimum alveolar concentrations, or predicted equivalent fentanyl–midazolam plasma concentrations. The shortening fraction and ejection fraction (using the modified Simpson rule) were calculated. Cardiac index was assessed by the velocity–time integral method. ResultsHalothane caused a significant decrease in mean arterial pressure, ejection fraction, and cardiac index, preserving only heart rate at baseline levels. Fentanyl–midazolam in combination caused a significant decrease in cardiac index secondary to a decrease in heart rate; contractility was maintained. Sevoflurane maintained cardiac index and heart rate and had less profound hypotensive and negative inotropic effects than halothane. Isoflurane preserved both cardiac index and ejection fraction, had less suppression of mean arterial pressure than halothane, and increased heart rate. ConclusionsIsoflurane and sevoflurane preserved cardiac index, and isoflurane and fentanyl–midazolam preserved myocardial contractility at baseline levels in this group of patients with congenital heart disease. Halothane depressed cardiac index and myocardial contractility.

Mediastinitis after pediatric cardiac surgery: a 15-year experience at a single institution

BACKGROUND The spectrum of sternal wound infections after cardiac surgery ranges from superficial infections to a deep sternal infection known as mediastinitis. Mediastinitis is a rare but clinically relevant source of postoperative morbidity and mortality in adult and pediatric patients after cardiac surgery. METHODS We retrospectively identified all patients diagnosed with mediastinitis after cardiac surgery from January 1987 to December 2002 (17 patients/7,616 surgeries = 0.2%). Demographic data, cardiac diagnosis, cardiac surgery, hospital length of stay, associated medical diagnosis, and surgical treatment for mediastinitis were collected. RESULTS Fifteen pediatric patients (age < 18 years) were diagnosed with mediastinitis (mean age at diagnosis 37.5 months, range 21 days to 17 years. The median postoperative day of diagnosis was 14 days (6 to 50 days). The most common organism was Staphylococcus species (n = 9). Six patients had an associated bacteremia. The median hospital length of stay for all patients was 42.5 days (range 16 to 163 days). The hospital mortality was 1 of 15 (6%). Each patient was treated with intravenous antibiotics; sternal debridement; and rectus abdominus flap reconstruction (n = 7), pectoralis muscle flap reconstruction (n = 3), omentum reconstruction (n = 1), or primary sternal closure (n = 4). Three patients have undergone redo-sternotomy with orthotopic heart transplantation, bidirectional cavopulmonary anastomosis, and replacement of a right ventricle to pulmonary artery homograft. CONCLUSIONS Timely diagnosis, aggressive sternal debridement, and liberal use of rotational muscle flaps can potentially minimize the morbidity and mortality in pediatric postoperative cardiac patients. Subsequent redo-sternotomy has not been problematic.

Outcomes of pediatric patients supported by the HeartMate II left ventricular assist device in the United States

OBJECTIVE The HeartMate II (HMII; Thoratec, Pleasanton, CA) continuous-flow left ventricular assist device (LVAD) is an established treatment modality for advanced heart failure in adults. The objective of this study was to evaluate outcomes of pediatric patients supported by the HMII LVAD. METHODS This was a retrospective review of the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) of patients supported with a HMII from April 2008 to September 2011. The primary cohort comprised pediatric patients aged 11 to 18 years. Outcomes were compared with a group of young adults aged 19 to 39 years who underwent HMII implant during the same period. Ischemic etiologies for heart failure were excluded. RESULTS There were 28 pediatric patients, of whom 19 (68%) were males, 14 (46%) were African American, and 7 (25%) underwent device placement in a pediatric hospital. Competing outcomes analysis showed that at 6 months of follow-up, the composite of survival to transplantation, ongoing support, or recovery was 96% for the pediatric group, which was not significantly different from the young adult group (96%, p = 0.330). The 2 groups had similar INTERMACS profiles but differed in diagnosis, weight, and morbidities. Bleeding complications requiring surgical intervention were more common in the pediatric group. CONCLUSIONS Pediatric outcomes with a HMII LVAD are comparable to that of young adults. As we continue to monitor this growing group, more sophisticated characterization and comparisons will be possible. Also, as technology progress and second- and third-generation devices are introduced, the number of children who will benefit from mechanical support will continue to grow.

Aortic arch advancement: the optimal one-stage approach for surgical management of neonatal coarctation with arch hypoplasia

BACKGROUND The optimal surgical treatment for neonatal coarctation with aortic arch hypoplasia (NCoAo/AAH) is controversial. Important long-term concerns include arch growth. We report our results obtained with a one-stage radical approach of coarctectomy and aortic arch advancement for NCoAo/AAH. METHODS From June 1995 to December 2000, 65 newborns with NcoAo/AAH underwent coarctectomy and aortic arch advancement via a median sternotomy under deep hypothermic circulatory arrest. Patients were classified by diagnosis: group 1, isolated NCoAo/AAH (n = 13); group 2, NCoAo/AAH with ventricular septal defect (n = 20); and group 3, NCoAo/AAH with complex cardiac lesions (n = 32). RESULTS The study population included 36 boys and 29 girls. Mean age was 13 +/- 1.7 days (range 1 to 43 days). Mild to moderate left ventricular outflow tract obstruction was present in 15 patients. Mean body weight was 3.4 +/- 0.1 kg (range 1.6 to 5 kg). Eight babies were premature. The mean Z value for the aortic arch was -4 +/- 0.3 (range -2 to -4.5) and for the isthmus -4.5 +/- 0.2 (range -3 to -7). Mean deep hypothermic circulatory arrest time was 28 +/- 2 minutes (range 14 to 60 minutes). Mean intensive care unit stay was 6 +/- 1 days (range 2 to 30 days). There were three early deaths (all in groups 2 and 3) and two late deaths (in group 3) (5-year actuarial survival, 91% +/- 7.9%). There was one recurrence (5-year actuarial freedom from recurrence, 98% +/- 4%). Peak Doppler velocity across the arch in the remaining patients was 1 +/- 0.1 m/s (range 0 to 2.2 m/s). CONCLUSIONS Coarctectomy and aortic arch advancement is the optimal surgical method for management of NCoAo/AAH. It has low operative morbidity and mortality and a very low incidence of recoarctation or arch obstruction.

The association between brain injury, perioperative anesthetic exposure, and 12‐month neurodevelopmental outcomes after neonatal cardiac surgery: a retrospective cohort study

Adverse neurodevelopmental outcomes are observed in up to 50% of infants after complex cardiac surgery. We sought to determine the association of perioperative anesthetic exposure with neurodevelopmental outcomes at age 12 months in neonates undergoing complex cardiac surgery and to determine the effect of brain injury determined by magnetic resonance imaging (MRI).

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 Childrens 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%.

Pulmonary-to-systemic blood flow ratio effects of sevoflurane, isoflurane, halothane, and fentanyl/midazolam with 100% oxygen in children with congenital heart disease.

The cardiovascular effects of volatile anesthetics in children with congenital heart disease have been studied, but there are limited data on the effects of anesthetics on pulmonary-to-systemic blood flow ratio (Qp:Qs) in patients with intracardiac shunting. In this study, we compared the effects of halothane, isoflurane, sevoflurane, and fentanyl/midazolam on Qp:Qs and myocardial contractility in patients with atrial (ASD) or ventricular (VSD) septal defects. Forty patients younger than 14 yr old scheduled to undergo repair of ASD or VSD were randomized to receive halothane, sevoflurane, isoflurane, or fentanyl/midazolam. Cardiovascular and echocardiographic data were recorded at baseline, randomly ordered 1 and 1.5 mean alveolar anesthetic concentration (MAC) levels, or predicted equivalent fentanyl/midazolam plasma levels. Ejection fraction (using the modified Simpson’s rule) was calculated. Systemic (Qs) and pulmonary (Qp) blood flow was echocardiographically assessed by the velocity-time integral method. Qp:Qs was not significantly affected by any of the four regimens at either anesthetic level. Left ventricular systolic function was mildly depressed by isoflurane and sevoflurane at 1.5 MAC and depressed by halothane at 1 and 1.5 MAC. Sevoflurane, halothane, isoflurane, or fentanyl/midazolam in 1 or 1.5 MAC concentrations or their equivalent do not change Qp:Qs in patients with isolated ASD or VSD.