Paul Samuels

Susceptibility of Transcranial Electric Motor-evoked Potentials to Varying Targeted Blood Levels of Dexmedetomidine during Spine Surgery

Background:Dexmedetomidine has been increasingly used as an adjunct to opioid–propofol total intravenous anesthesia (TIVA). The authors tested the hypothesis and found that clinically relevant blood levels of dexmedetomidine do not produce significant attenuation of the amplitude of transcranial electric motor-evoked potentials either independently or by interaction with propofol in a dose-dependent manner. Methods:The authors planned to recruit 72 patients with idiopathic scoliosis who had posterior spine fusion surgery during propofol and remifentanil TIVA with dexmedetomidine as an adjunct. However, the authors terminated the study after enrolling 44 patients because of change in surgical technique. Before administering dexmedetomidine, baseline transcranial electric motor-evoked potentials were acquired during TIVA with remifentanil and propofol. Patients were randomized to varying targeted blood levels of dexmedetomidine (0.4, 0.6, and 0.8 ng/ml) and propofol (2.5, 3.75, and 5 &mgr;g/ml) using a factorial design. The primary outcome variable was amplitude of transcranial electric motor-evoked potential. The secondary outcome was amplitude of cortical somatosensory-evoked potentials. Results:Of the 44 recruited patients, 40 completed the study, and their data were analyzed. The administration of dexmedetomidine in increasing doses as an adjunct to propofol-based TIVA caused a clinically and statistically significant attenuation of amplitudes of transcranial electric motor-evoked potentials. Conclusion:The authors conclude that under the stimulation conditions used, dexmedetomidine as an anesthetic adjunct to propofol-based TIVA at clinically relevant target plasma concentrations (0.6–0.8 ng/ml) can significantly attenuate the amplitude of transcranial electric motor-evoked potentials.

Quality of recovery from two types of general anesthesia for ambulatory dental surgery in children: a double-blind, randomized trial

Background:  Pediatric dental procedures are increasingly performed under general anesthesia because of the inability to cooperate, situational anxiety, or other behavioral problems. Volatile anesthetics have been associated with emergence delirium in children, whereas the use of propofol for anesthetic maintenance has been shown to reduce the incidence of emergence delirium after other types of surgeries. The aim of this study is to compare a sevoflurane‐based anesthetic with a propofol‐based technique as it relates to the incidence of emergence delirium and the quality of recovery after pediatric dental surgery, in patients who present with risk factors for perioperative behavioral issues.

Loss of Transcranial Electric Motor Evoked Potentials during Pediatric Spine Surgery with Dexmedetomidine

INTRAOPERATIVE neurophysiologic monitoring using transcranial electric motor evoked potentials (TceMEP) has been increasingly used to reduce the risk of spinal cord injury during corrective spine surgery. Because inhalational anesthetic agents considerably depress TceMEP amplitude in a dose-dependent manner, total intravenous anesthesia (TIVA) techniques with propofol as a central component have been advocated to optimize TceMEP monitoring during spine surgery. Because of its ability to decrease propofol requirements during TIVA, we often use dexmedetomidine, an -2 agonist, as an adjunct to TIVA for procedures requiring TceMEP monitoring. We report two pediatric patients who experienced deterioration of TceMEP signal during the intraoperative use of dexmedetomidine.

Competency and professionalism in medicine

Background:  In this article some definitions of competency and professionalism will be discussed, and an overview of existing methods that assess competency and professionalism in anaesthesia resident doctors (residents) is provided. In addition, we will discuss how progression to professionalism, education in anaesthesiology and other medical specialties may be improved using the adult skill acquisition model. The goal of this paper is to refine the definitions of professionalism and competency, and to propose a new approach to medical education.

Anesthesia for adolescent bariatric surgery.

For the first time in history, obesity rivals malnutrition as the most lifethreatening dietary disorder facing humanity. Pediatric obesity has become an international public health crisis with more than 22million of the world’s children under the age of 5 years overweight. The increasing prevalence of obesity in children and adolescents, combined with the growing recognition that many of the comorbidities of obesity begin in childhood, has made pediatric obesity a subject of great concern to healthcare providers. Two thirds of American adults are now characterized by the Centers for Disease Control and Prevention (CDC) as overweight, and obesity rates among children and adolescents have also reached alarming proportions. The prevalence of pediatric obesity in the United States, defined as >95th percentile body mass index (BMI) for age, tripled during the past 3 decades, increasing from 5% in the 1960s to 16% in the late 1990s. Obesity rates are even higher among black and Mexican-American children. The number of individuals with extreme obesity rose disproportionately during the past 20 years; individuals with a BMI of >40 kg/m increased 4-fold, whereas those with a BMI >50 kg/m increased 5-fold since 1986. Complicating the increase in prevalence is the recognition that obesity is remarkably refractory to medical treatment, and that most dieters will ultimately regain the weight they have lost. As a result of the explosive growth in severe obesity and the failure of dietary and behavioral intervention to treat it, surgeons are applying bariatric surgery techniques previously reserved for obese adults to adolescents. The Cincinnati Children’s Hospital Comprehensive Weight Management Program was developed in 2001 for the evaluation and surgical treatment of adolescents with severe obesity. This review focuses on our experience with this challenging patient population, including the epidemiology and comorbidities of childhood and adolescent obesity, as well as surgical technique, patient selection, and anesthetic implications of adolescent bariatric surgery.

Medullary thyroid cancer in a 9-week-old infant with familial MEN 2B: Implications for timing of prophylactic thyroidectomy.

BackgroundPatients with Multiple Endocrine Neoplasia type 2 (MEN 2) are at high risk of developing aggressive medullary thyroid carcinoma (MTC) in childhood, with the highest risk in those with MEN type 2B (of whom >95% have an M918T RET proto-oncogene mutation). Metastatic MTC has been reported as young as 3 months of age. Current guidelines recommend prophylactic thyroidectomy within the first year of life for MEN 2B.Patient findingsWe report a 9-week-old infant with MTC due to familial MEN 2B. A full-term male infant, born to a mother with known MEN 2B and metastatic MTC, had an M918T RET proto-oncogene mutation confirmed at 4 weeks of age. He underwent prophylactic total thyroidectomy at 9 weeks of age. Pathology showed a focal calcitonin-positive nodule (2.5 mm), consistent with microscopic MTC.SummaryThis case highlights the importance of early prophylactic thyroidectomy in MEN 2B. Although current guidelines recommend surgery up to a year of life, MTC may occur in the first few weeks of life, raising the question of how early we should intervene. In this report, we discuss the risks, benefits and barriers to performing earlier thyroidectomy, soon after the first month of life, and make suggestions to facilitate timely intervention. Prenatal anticipatory surgical scheduling could be considered in familial MEN 2B. Multidisciplinary collaboration between adult and pediatric specialists is key to the optimal management of the infant at risk.

Insufflation vs intubation during esophagogastroduodenoscopy in children.

Objectives:  We compared adverse airway events during esophagogastroduodenoscopy (EGD) in children managed with insufflation vs intubation.

Anesthetic management of patients with tracheal T-tubes.

Aims:  To better inform the preoperative anesthesia assessment, we review the rationale of tracheal T‐tubes and the maintenance they require. We then describe specific intraoperative techniques to administer inhalational agents and maintain respiration in patients with tracheal T‐tubes.

Education in pediatric anesthesiology: competency, innovation, and professionalism in the 21st century.

At the end of the chapter the reader would be able to: 1. identify the specific factors that are impacting health care and transforming medical education; 2. indicate the main goals of education in anesthesiology/pediatric anesthesiology; 3. explain the definition of “competency” and the measurement tools available; 4. analyze the challenges of pediatric anesthesiology training and summarize the requirements for program accreditation; 5. describe the new educational tools in anesthesiology/pediatric anesthesiology and assess the weight they have on the future of our specialty.

Spurious diagnosis of a cervical mass due to a laryngeal mask airway.

The laryngeal mask airway (LMA) has become a popular alternative to endotracheal intubation. We report a case in which appropriate LMA placement resulted in an unrecognized neck mass and subsequent erroneous diagnosis of cervical lymphadenopathy. Otolaryngologists should be aware that the LMA may result in alterations of neck anatomy.