Stephen A. Stayer

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.

Neurological monitoring for congenital heart surgery.

The incidence of neurological complications after pediatric cardiac surgery ranges from 2% to 25%. The causes are multifactorial and include preoperative brain malformations, perioperative hypoxemia and low cardiac output states, sequelae of cardiopulmonary bypass, and deep hypothermic circulatory arrest. Neurological monitoring devices are readily available and the anesthesiologist can now monitor the brain during pediatric cardiac surgery. In this review we discuss near-infrared cerebral oximetry, transcranial Doppler ultrasound, and electroencephalographic monitors for use during congenital heart surgery. After review of the basic principles of each monitoring modality, we discuss their uses during pediatric heart surgery. We present evidence that multimodal neurological monitoring in conjunction with a treatment algorithm may improve neurological outcome for patients undergoing congenital heart surgery and present one such algorithm.

The Use of Lidocaine for Preventing the Withdrawal Associated with the Injection of Rocuronium in Children and Adolescents

UNLABELLED We designed this study to examine the incidence and degree of movement after the administration of rocuronium in children and adolescents and to measure the treatment effect of lidocaine for its prevention. One hundred patients (aged 5-18 yr) were randomly assigned to two groups. After general anesthesia was induced with 5 mg/kg thiopental sodium and manual occlusion of venous outflow was performed, one group of patients received 0.1 mL/kg 1% lidocaine i.v.. A second group received 0.1 mL/kg of isotonic sodium chloride solution as a placebo control. Venous outflow occlusion was held for 15 s, released, and immediately followed by the administration of rocuronium 1 mg/kg i.v.. The patients response to rocuronium injection was graded using a 4-point scale. We observed that the incidence of withdrawal was 84% in the placebo group and was significantly decreased to 46% in patients pretreated with lidocaine (P < 0.001). This study demonstrates that the i.v. injection of rocuronium is commonly associated with a withdrawal reaction in anesthetized pediatric patients and that this reaction can be attenuated or eliminated by pretreatment with i.v. lidocaine. IMPLICATIONS Pain on injection of rocuronium in pediatric patients can be alleviated by pretreatment with i.v. lidocaine.

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.

Outcomes for extremely premature infants

Premature birth is a significant cause of infant and child morbidity and mortality. In the United States, the premature birth rate, which had steadily increased during the 1990s and early 2000s, has decreased annually for 7 years and is now approximately 11.39%. Human viability, defined as gestational age at which the chance of survival is 50%, is currently approximately 23 to 24 weeks in developed countries. Infant girls, on average, have better outcomes than infant boys. A relatively uncomplicated course in the intensive care nursery for an extremely premature infant results in a discharge date close to the prenatal estimated date of confinement. Despite technological advances and efforts of child health experts during the last generation, the extremely premature infant (less than 28 weeks gestation) and extremely low birth weight infant (<1000 g) remain at high risk for death and disability with 30% to 50% mortality and, in survivors, at least 20% to 50% risk of morbidity. The introduction of continuous positive airway pressure, mechanical ventilation, and exogenous surfactant increased survival and spurred the development of neonatal intensive care in the 1970s through the early 1990s. Routine administration of antenatal steroids during premature labor improved neonatal mortality and morbidity in the late 1990s. The recognition that chronic postnatal administration of steroids to infants should be avoided may have improved outcomes in the early 2000s. Evidence from recent trials attempting to define the appropriate target for oxygen saturation in preterm infants suggests arterial oxygen saturation between 91% and 95% (compared with 85%–89%) avoids excess mortality; however, final analyses of data from these trials have not been published, so definitive recommendations are still pending. The development of neonatal neurocritical intensive care units may improve neurocognitive outcomes in this high-risk group. Long-term follow-up to detect and address developmental, learning, behavioral, and social problems is critical for children born at these early gestational ages.The striking similarities in response to extreme prematurity in the lung and brain imply that agents and techniques that benefit one organ are likely to also benefit the other. Finally, because therapy and supportive care continue to change, the outcomes of extremely low birth weight infants are ever evolving. Efforts to minimize injury, preserve growth, and identify interventions focused on antioxidant and anti-inflammatory pathways are now being evaluated. Thus, treating and preventing long-term deficits must be developed in the context of a “moving target.”

The optimal length of insertion of central venous catheters for pediatric patients.

Incorrect positioning of central venous catheters (CVC) in infants and children may lead to serious complications such as perforation of the heart or great vessels. CVC position is not usually assessed until the first postoperative chest radiograph, potentially leaving malposition undetected for several hours. We studied a series of 452 right internal jugular and subclavian catheter placements in infants and children undergoing surgery for congenital heart disease, and measured the distance from the skin insertion site to the radiographic junction of the superior vena cava and right atrium (RA). Based on these data, the following formulae predict that a CVC will be positioned above the RA 97% of the time: correct length of insertion (cm) = (height in cm/10) − 1 for patients ≤100 cm in height, and (height in cm/10) − 2 for patients >100 cm in height. Weight-based recommendations were also developed which predict placement of CVC above the RA 98% of the time.

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

UNLABELLED 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.

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).

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.