Aymen Naguib

Dexmedetomidine: Applications for the Pediatric Patient With Congenital Heart Disease

This study aimed to provide a general description of the cardiovascular and hemodynamic effects of dexmedetomidine and an evidence-based review of the literature regarding its use in infants and children with congenital heart disease (CHD). A computerized bibliographic search of the literature on dexmedetomidine use in infants and children with CHD was performed. The cardiovascular effects of dexmedetomidine have been well studied in animal and adult human models. Adverse cardiovascular effects include occasional episodes of bradycardia, with rare reports of sinus pause or cardiac arrest. Both hypotension and hypertension also have been reported. The latter is related to peripheral α2B agonism leading to vasoconstriction. No adverse effects on the pulmonary vasculature have been noted even in patients with preexisting pulmonary hypertension. Although there are no direct effects on myocardial function, decreased cardiac output may result from changes in heart rate or increases in afterload. Although not currently Food and Drug Administration (FDA)-approved for the pediatric population, findings have shown dexmedetomidine to be effective in various clinical scenarios of patients with CHD including sedation during mechanical ventilation, prevention of procedure-related anxiety, prevention of emergence delirium and shivering after anesthesia, and treatment of withdrawal. Although dexmedetomidine may have limited utility for painful or invasive procedures, preliminary data suggest that the addition of ketamine to the regimen may offer benefits. When used during the perioperative period, additional benefits include blunting of the sympathetic stress response with a reduction of endogenous catecholamine release, a decrease in intraoperative anesthetic requirements, and a limitation of postoperative opioid requirements.

Chest wall rigidity in two infants after low-dose fentanyl administration.

Since its introduction into clinical practice, it has been known that fentanyl and other synthetic opioids may cause skeletal muscle rigidity. Involvement of the respiratory musculature, laryngeal structures, or the chest wall may impair ventilation, resulting in hypercarbia and hypoxemia. Although most common with the rapid administration of large doses, this rare adverse effect may occur with small doses especially in neonates and infants. We present 2 infants who developed chest wall rigidity, requiring the administration of neuromuscular blocking agents and controlled ventilation after analgesic doses of fentanyl. Previous reports regarding chest wall rigidity after the administration of low-dose fentanyl in infants and children are reviewed, the pathogenesis of the disorder is discussed, and treatment options offered.

Anesthetic management of the hybrid stage 1 procedure for hypoplastic left heart syndrome (HLHS).

Introduction:  Despite advances in the surgical and perioperative management of patients with hypoplastic left heart syndrome (HLHS), outcomes for this high‐risk group of patients remains suboptimal. The hybrid approach [bilateral pulmonary artery (PA) banding, ductal stenting, balloon atrial septostomy], is an emerging alternative therapy for the management of HLHS, which defers the risks of a major surgical repair until the infants are older. This article will describe our experience providing the anesthetic management of patients undergoing the hybrid procedure.

Predictors of Successful Early Extubation Following Congenital Cardiac Surgery in Neonates and Infants

BACKGROUND There is a paucity of literature discussing the predictive likelihood of successfully extubating neonates and infants in the operating room immediately following congenital cardiac surgery. Given the unknown consequences of anaesthetics on neurodevelopmental outcomes, minimising the exposure of this population to such agents may have long-term benefits. METHODS Retrospective chart review of 391 patients less than 1 year of age. RESULTS The probability of successfully extubating these patients was based on quantifiable, objective criteria. The relevant variables include age, weight, bypass time, lactate level and specific congenital anomaly. CONCLUSIONS The practice of immediate extubation of infants and neonates is achievable, safe and predicted based on specific patient variables. This practice will minimise the anaesthetic exposure of these especially young patients who may be at risk for long-term consequences related to anaesthetic exposure.

Dexmedetomidine controls junctional ectopic tachycardia during Tetralogy of Fallot repair in an infant.

Dexmedetomidine is a highly selective α2 -adrenergic agonist approved for short-term sedation and monitored anesthesia care in adults. Although not approved for use in the pediatric population, an increasing number of reports describe its use in pediatric patients during the intraoperative period and in the intensive care unit. Dexmedetomidine can potentially have an adverse impact on the cardiovascular system secondary to its negative chronotropic and dromotropic effects. However, it is these cardiac effects that are currently being explored as a therapeutic option for the treatment of perioperative tachyarrhythmias in pediatric patients with congenital heart disease (CHD). We report the use of dexmedetomidine to treat junctional ectopic tachycardia (JET), which developed following cardiopulmonary bypass for surgical correction of Tetralogy of Fallot in a 6-week-old infant. Within 15 min of increasing the dexmedetomidine infusion from 0.5 to 3 μg/kg/h, JET converted to normal sinus rhythm. This case report provides additional anecdotal evidence that dexmedetomidine may have a therapeutic role in the treatment of perioperative tachyarrhythmias in pediatric patients with CHD. The specific effects of dexmedetomidine on the cardiac conduction system are reviewed followed by a summary of previous reports describing its use as a therapeutic agent to treat perioperative arrhythmias.

A single-center strategy to minimize blood transfusion in neonates and children undergoing cardiac surgery.

The transfusion of blood products in the setting of uncontrolled bleeding is unquestionably lifesaving. However, in many instances, the decision to transfuse is based on physician gestalt rather than medical evidence. When indications for transfusion are unclear, the benefits of blood products must be balanced against their significant risks and associated costs. As our institution is a referral center for patients of Jehovahs Witness faith, this population has pushed our development of techniques to achieve the goal of bloodless surgery. Our practices in caring for this population have become our standard practice for managing all patients undergoing congenital cardiac surgery.

Comprehensive evaluation of lung allograft function in infants after lung and heart-lung transplantation

BACKGROUND Limited data exist on methods to evaluate allograft function in infant recipients of lung and heart-lung transplants. At our institution, we developed a procedural protocol in coordination with pediatric anesthesia where infants were sedated to perform infant pulmonary function testing, computed tomography imaging of the chest, and flexible fiberoptic bronchoscopy with transbronchial biopsies. METHODS A retrospective review was performed of children aged younger than 1 year who underwent lung or heart-lung transplantation at our institution to assess the effect of this procedural protocol in the evaluation of infant lung allografts. RESULTS Since 2005, 5 infants have undergone thoracic transplantation (3 heart-lung, 2 lung). At time of transplant, the mean ± standard deviation age was 7.2 ± 2.8 months (range, 3-11 months). Of 24 procedural sessions performed to evaluate lung allografts, 83% (20 of 24) were considered surveillance where the patients were completely asymptomatic. Of the surveillance procedures, 80% were performed as an outpatient, whereas 20% were done as inpatients during the lung or heart-lung transplant post-operative period before discharge home. Sedation was performed with propofol alone (23 of 24) or in addition to ketamine (1 of 24) infusion; mean sedation time was 141 ± 39 minutes (range, 70-214) minutes. Of the 16 outpatient procedures, patients were discharged after 14 (88%) on the same day, and after 2 (12%) were admitted for observation, with 1 being due to transportation issues and the other due to fever during the observation period. CONCLUSIONS A comprehensive procedural protocol to evaluate allograft function in infant lung and heart-lung transplant recipients was performed safely as an outpatient.

Revisiting acute normovolemic hemodilution and blood transfusion during pediatric cardiac surgery: a prospective observational study

The majority of allogeneic transfusions occur in the perioperative setting, especially during cardiac surgery. In addition to the economic implications, there is emerging evidence that blood transfusion may increase both morbidity and mortality. Acute normovolemic hemodilution (ANH) may limit the need for blood products.

Dexmedetomidine controls supraventricular tachycardia following cardiac surgery in a child.

Dexmedetomidine is an α2-adrenergic agonist which initially received US Food and Drug Administration (FDA) approval in the United States in 1999 for the sedation of adults during mechanical ventilation and then in 2009 for monitored anesthesia care. Although generally viewed as an adverse effect, bradycardia and the negative chronotropic effects may be beneficial in certain patient populations and have occasionally been used as a therapeutic maneuver. We present a case summary describing intraoperative and postoperative use of dexmedetomidine to treat and control supraventricular tachycardia in a 5-year-old boy undergoing surgical repair of a large atrial septal defect. The specific effects of dexmedetomidine on the cardiac conduction system are reviewed and previous reports of its use as a therapeutic agent for the treatment of perioperative tachyarrhythmias are discussed.

Changes in Near-Infrared Spectroscopy and the Bispectral Index During Tilt-Table Examination

The head-upright tilt-table test is an important tool for the diagnosis of vasodepressor or neurocardiogenic syncope. The use of noninvasive near-infrared spectroscopy (NIRS) monitoring and bispectral index (BIS) monitoring during these cases can add another tool to the real-time monitoring and aid in their diagnosis. The authors report their experience using NIRS and BIS monitoring during tilt-table testing to investigate syncope in a 14-year-old adolescent. In this case, changes in the NIRS occurred earlier than changes in either blood pressure or the development of clinical symptoms. The change in the NIRS and BIS values correlated with the patient’s level of consciousness. One major advantage of monitors such as the BIS, and more importantly, the NIRS is that they provide an instantaneous and continuous noninvasive measure of cerebral perfusion.