A novel, cassette-based nitric oxide delivery system with an advanced feedback control algorithm accurately delivers nitric oxide via the anesthesia machine independent of fresh gas flow rate and volatile anesthetic agent.

Nitric oxide (NO), a selective pulmonary vasodilator, can be delivered via conventional ICU and anesthesia machine ventilators. Anesthesia machines are designed for rebreathing of circulating gases, reducing volatile anesthetic agent quantity used. Current cylinder- and ionizing-based NO delivery technologies use breathing circuit flow to determine NO delivery and do not account for recirculated gases; therefore, they cannot accurately dose NO at FGF below patient minute ventilation (MV). A novel, cassette-based NO delivery system (GENOSYL® DS, Vero Biotech Inc.) uses measured NO concentration in the breathing circuit as an input to an advanced feedback control algorithm, providing accurate NO delivery regardless of FGF and recirculation of gases. This study evaluated GENOSYL® DS accuracy with different anesthesia machines, ventilation parameters, FGFs, and volatile anesthetics. GENOSYL® DS was tested with GE Aisys and Dräger Fabius anesthesia machines to determine NO dose accuracy with FGF < patient MV, and with a Getinge Flow-i anesthesia machine to determine NO dose accuracy when delivering various volatile anesthetic agents. Neonatal and adult mechanical ventilation parameters and circuits were used. GENOSYL® DS maintained accurate NO delivery with all three anesthesia machines, at low FGF with recirculation of gases, and with all volatile anesthetic agents at different concentrations. Measured NO2 levels remained acceptable at ≤ 1 ppm with set NO dose ≤ 40 ppm. GENOSYL® DS, with its advanced feedback control algorithm, is the only NO delivery system capable of accurately dosing NO with anesthesia machines with rebreathing ventilation parameters (FGF < MV) regardless of anesthetic agent.

Use of compressed sensing to reduce scan time and breath-holding for cardiac cine balanced steady-state free precession magnetic resonance imaging in children and young adults.

BACKGROUND: Conventional pediatric volumetric MRI acquisitions of a short-axis stack typically require multiple breath-holds under anesthesia. OBJECTIVE: Here, we aimed to validate a vendor-optimized compressed-sensing approach to reduce scan time during short-axis balanced steady-state free precession (bSSFP) cine imaging. MATERIALS AND METHODS: Imaging was performed in 28 patients (16±9 years) in this study on a commercial 3-tesla (T) scanner using retrospective electrocardiogram-gated cine bSSFP. Cine short-axis images covering both ventricles were acquired with conventional parallel imaging and a vendor-optimized parallel imaging/compressed-sensing approach. Qualitative Likert scoring for blood-myocardial contrast, edge definition, and presence of artifact was performed by two experienced radiologists. Quantitative comparisons were performed including biventricular size and function. A paired t-test was used to detect significant differences (P<0.05). RESULTS: Scan duration was 7±2 s/slice for conventional imaging (147±33 s total) vs. 4±2 s/slice for compressed sensing (83±28 s total). No significant differences were found with qualitative image scores for blood-myocardial contrast, edge definition, and presence of artifact. No significant differences were found in volumetric analysis between the two sequences. The number of breath-holds was 10±4 for conventional imaging and 5±3 for compressed sensing. CONCLUSION: Compressed sensing allowed for a 50% reduction in the number of breath-holds and a 43% reduction in the total scan time without differences in the qualitative or quantitative measurements as compared to the conventional technique.

Williams syndrome.

Williams syndrome affects approximately one in 10 000 people and is caused by the deletion of genes on chromosome 7q11.23 which code for elastin. The phenotypic appearance of people with Williams syndrome is well characterized, but there continues to be new genetic and therapeutic discoveries. Patients with Williams syndrome have increased morbidity and mortality under sedation and anesthesia, largely as a result of cardiovascular abnormalities. This review article focuses on new information about Williams syndrome and outlines a structured approach to patients with Williams syndrome in the perioperative period.

Outstanding contribution to pediatric anesthesiology: An interview with Dr. Robert H. Friesen.

Dr. Robert H. Friesen, (1946-) Professor of Anesthesiology, Children's Hospital Colorado, University of Colorado, Anschutz Medical Campus, has played a pivotal and pioneering role in the development of pediatric and congenital cardiac anesthesiology. His transformative research included the study of the hemodynamic effects of inhalational and intravenous anesthetic agents in the newborn and the effects of anesthetic agents on pulmonary vascular resistance in patients with pulmonary hypertension. As a model clinician-scientist, educator, and administrator, he changed the practice of pediatric anesthesia and shaped the careers of hundreds of physicians-in-training, imbuing them with his core values of honesty, integrity, and responsibility. Based on a series of interviews with Dr. Friesen, this article reviews a career that advanced pediatric and congenital cardiac anesthesia during the formative years of the specialties.

Hemodynamic response to ketamine in children with pulmonary hypertension.

BACKGROUND: The safety of ketamine in children with pulmonary hypertension has been debated because of conflicting results of prior studies in which changes in mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) have been widely variable. The goal of this prospective study was to quantitate the effects of ketamine on pulmonary hemodynamics in a cohort of children with pulmonary hypertension under conditions in which variables such as airway/ventilatory management, FiO(2), and use of vasodilating anesthetics were controlled. METHODS: The IRB approved this study of 34 children undergoing cardiac catheterization for pulmonary hypertension studies. Following anesthetic induction with sevoflurane and tracheal intubation facilitated by the administration of rocuronium 0.7-1 mg·kg(-1) iv, sevoflurane was discontinued and anesthesia was maintained with midazolam 0.1 mg·kg(-1) iv (or 0.5 mg·kg(-1) po preoperatively) and remifentanil iv infusion 0.5-0.7 mcg·kg(-1) ·min(-1). Ventilation was mechanically controlled to maintain PaCO(2) 35-40 mmHg. When endtidal sevoflurane was 0% and FiO(2) was 0.21, baseline heart rate (HR), mean arterial pressure (MAP), mPAP, right atrial pressure (RAP), pulmonary artery occlusion pressure (PAOP), right ventricular end-diastolic pressure (RVEDP), cardiac output, and arterial blood gases were measured, and indexed systemic vascular resistance (SVRI), indexed pulmonary vascular resistance (PVRI), and cardiac index (CI) were calculated. Each child then received a bolus of ketamine 2 mg·kg(-1) infused over 2 min. Measurements and calculations were repeated 2 min after the conclusion of the infusion. RESULTS: The mean (95% CI) increase in mPAP following ketamine was 2 mmHg (0.2, 3.7), which was statistically significant but clinically insignificant. PVRI and PVRI/SVRI did not change significantly. Hemodynamic changes did not differ among subjects with differing severity of pulmonary hypertension or between subjects chronically treated with pulmonary vasodilators or not. CONCLUSION: Ketamine is associated with minimal, clinically insignificant hemodynamic changes in sedated, mechanically ventilated children with pulmonary hypertension.

Impact of general anesthesia on the echocardiographic assessment of right ventricular function in pediatric patients with pulmonary arterial hypertension.

One of the great diagnostic challenges for children with pulmonary arterial hypertension is the need for general anesthesia (GA) to enable successful right heart catheterization. Here, for the first time, we describe how echocardiographic estimates of right ventricular function and pulmonary pressures change in pediatric patients during GA.

The hemodynamic response to dexmedetomidine loading dose in children with and without pulmonary hypertension.

BACKGROUND: Dexmedetomidine, an α-2 receptor agonist, is widely used in children with cardiac disease. Significant hemodynamic responses, including systemic and pulmonary vasoconstriction, have been reported after dexmedetomidine administration. Our primary goal of this prospective, observational study was to quantify the effects of dexmedetomidine initial loading doses on mean pulmonary artery pressure (PAP) in children with and without pulmonary hypertension. METHODS: Subjects were children undergoing cardiac catheterization for either routine surveillance after cardiac transplantation (n = 21) or pulmonary hypertension studies (n = 21). After anesthetic induction with sevoflurane and tracheal intubation, sevoflurane was discontinued and anesthesia was maintained with midazolam 0.1 mg/kg i.v. (or 0.5 mg/kg orally preoperatively) and remifentanil i.v. infusion 0.5 to 0.8 µg/kg/min. Ventilation was mechanically controlled to maintain PCO2 35 to 40 mm Hg. When end-tidal sevoflurane was 0% and fraction of inspired oxygen (FIO2) was 0.21, baseline heart rate, mean arterial blood pressure, PAP, right atrial pressure, pulmonary artery occlusion pressure, right ventricular end-diastolic pressure, cardiac output, and arterial blood gases were measured, and indexed systemic vascular resistance, indexed pulmonary vascular resistance, and cardiac index were calculated. Each subject then received a 10-minute infusion of dexmedetomidine of 1 µg/kg, 0.75 µg/kg, or 0.5 µg/kg. Measurements and calculations were repeated at the conclusion of the infusion. RESULTS: Most hemodynamic responses were similar in children with and without pulmonary hypertension. Heart rate decreased significantly, and mean arterial blood pressure and indexed systemic vascular resistance increased significantly. Cardiac index did not change. A small, statistically significant increase in PAP was observed in transplant patients but not in subjects with pulmonary hypertension. Changes in indexed pulmonary vascular resistance were not significant. CONCLUSION: Dexmedetomidine initial loading doses were associated with significant systemic vasoconstriction and hypertension, but a similar response was not observed in the pulmonary vasculature, even in children with pulmonary hypertension. Dexmedetomidine does not appear to be contraindicated in children with pulmonary hypertension.

Cryoprecipitate and platelet administration during modified ultrafiltration in children less than 10 kg undergoing cardiac surgery.

UNLABELLED: The timing of blood product administration after cardiopulmonary bypass (CPB) may influence the amount of postoperative transfusion and chest tube output. We performed a retrospective study of a novel technique of administering blood products during modified ultrafiltration (MUF) in congenital cardiac surgery. A Control Group (CG; n = 55) received cryoprecipitate and platelets after modified ultrafiltration. The Treatment Group (TG; n = 59) received cryoprecipitate and platelets during MUF. Volumes of blood products transfused in the operating room, initial coagulation parameters in the cardiac intensive care unit, and first 24-hour chest tube output were recorded. Age (116 +/- 198 versus 84 +/- 91 days), weight (4.6 +/- 1.8 versus 4.5 +/- 1.4 kg), duration of bypass (121 +/- 50 versus 139 +/- 57 minutes), and Aristotle scoring (9.3 +/- 2.7 versus 9.1 +/- 3.1) were not significantly different when comparing the control and treatment groups, respectively. Intraoperative packed red blood cells (74.4 +/- 34.8 versus 79.3 +/- 58.0 mL/kg, p = .710), fresh-frozen plasma (58.3 +/- 27.1 versus 59.1 +/- 27.2 mL/kg, p = .849), cryoprecipitate (7.3 +/- 5.1 versus 8.6 +/- 5.9 mL/kg, p = .109), and platelet (19.0 +/- 14.6 versus 23.7 +/- 20.8 mL/kg, p = .176) administration were the same in the control and treatment groups, respectively. However, fibrinogen levels on arrival in the coronary intensive care unit were significantly higher (305 +/- 80 versus 255 +/- 40 mg/dL, p < .001) in the CG compared with the TG. Twenty-four-hour chest tube output was not significantly different but the CG (17.76 +/- 9.34 mL/kg/24 hours) was trending lower than the TG (19.52 +/- 10.94 mL/kg/24 hours, p = .357). In an attempt to minimize CPB-associated bleeding and transfusions, we changed our practice by adjusting the timing of blood product administration after patient separation from CPB. The goals of the change in practice were not measurably different in terms of shorter intraoperative times, fewer blood transfusions, or less chest tube output at our institution. KEYWORDS: congenital heart disease, modified ultrafiltration, cryoprecipitate, platelets, cardiopulmonary bypass.

Multi-Disciplinary Management and Surgical Resection of Intracardiac Fibromas Causing Bilateral Ventricular Outflow Tract Obstructions in an Infant.

Cardiac tumors remain rare in children with benign pathologies predominating. Indications for surgical management often result from compromised ventricular chamber size, biventricular outflow tract obstruction, impaired ventricular function, or the presence of medically refractory dysrhythmias. We present a case of a six-month-old infant with two intracardiac fibromas originating in the interventricular septum. The fibromas were causing significant biventricular outflow obstruction. The patient successfully underwent tumor resection on cardiopulmonary bypass The literature on pediatric cardiac tumors is reviewed. Multi-disciplinary medical planning is necessary for successful anesthetic and surgical treatment of this high-risk patient population.

Validation of Point-of-Care Ultrasound to Measure Perioperative Edema in Infants With Congenital Heart Disease.

Purpose: Fluid overload is a common post-operative issue in children following cardiac surgery and is associated with increased morbidity and mortality. There is currently no gold standard for evaluating fluid status. We sought to validate the use of point-of-care ultrasound to measure skin edema in infants and assess the intra- and inter-user variability. Methods: Prospective cohort study of neonates (≤30 d/o) and infants (31 d/o to 12 m/o) undergoing cardiac surgery and neonatal controls. Skin ultrasound was performed on four body sites at baseline and daily post-operatively through post-operative day (POD) 3. Subcutaneous tissue depth was manually measured. Intra- and inter-user variability was assessed using intraclass correlation coefficient (ICC). Results: Fifty control and 22 surgical subjects underwent skin ultrasound. There was no difference between baseline surgical and control neonates. Subcutaneous tissue increased in neonates starting POD 1 with minimal improvement by POD 3. In infants, this pattern was less pronounced with near resolution by POD 3. Intra-user variability was excellent (ICC 0.95). Inter-user variability was very good (ICC 0.82). Conclusion: Point-of-care skin ultrasound is a reproducible and reliable method to measure subcutaneous tissue in infants with and without congenital heart disease. Acute increases in subcutaneous tissue suggests development of skin edema, consistent with extravascular fluid overload. There is evidence of skin edema starting POD 1 in all subjects with no substantial improvement by POD 3 in neonates. Point-of-care ultrasound could be an objective way to measure extravascular fluid overload in infants. Further research is needed to determine how extravascular fluid overload correlates to clinical outcomes.

Hypnotic depth and the incidence of emergence agitation and negative postoperative behavioral changes.

BACKGROUND: Emergence agitation (EA) and negative postoperative behavioral changes (NPOBC) are common in children, although the etiology remains unclear. We investigated whether longer times under deep hypnosis as measured by Bispectral Index (BIS) monitoring would positively correlate with a greater incidence of EA in the PACU and a greater occurrence of NPOBC in children after discharge. METHODS: We enrolled 400 children, 1-12 years old, scheduled for dental procedures under general anesthesia. All children were induced with high concentration sevoflurane, and BIS monitoring was continuous from induction through recovery in the PACU. A BIS reading <45 was considered deep hypnosis. The presence of EA was assessed in the PACU using the Pediatric Anesthesia Emergence Delirium scale. NPOBC were assessed using the Post-Hospital Behavior Questionnaire, completed by parents 3-5 days postoperatively. Data were analyzed using logistic regression, with a P < 0.05 considered statistically significant. RESULTS: The incidence of EA was 27% (99/369), and the incidence of NPOBC was 8.8% (28/318). No significant differences in the incidence of EA or NPOBC were seen with respect to length of time under deep hypnosis as measured by a BIS value of <45. CONCLUSION: Our data revealed no significant correlation between the length of time under deep hypnosis (BIS < 45) and the incidence of EA or NPOBC. Within this population, these behavioral disturbances do not appear to be related to the length of time under a deep hypnotic state as measured by the BIS.