Acetaminophen pharmacokinetics in infants and children with congenital heart disease.

BACKGROUND: Acetaminophen is routinely used for perioperative analgesia in children undergoing major surgical procedures. There are few estimates of acetaminophen pharmacokinetic parameters in children with congenital heart disease, especially those with cyanotic heart disease. AIMS: The current study prospectively investigated differences in acetaminophen pharmacokinetics following surgery using cardiopulmonary bypass in children with cyanotic and acyanotic congenital heart disease. METHODS: Children (2-6 years, 9-23 kg) presenting for median sternotomy for Fontan palliation (cyanotic patients) or two ventricle surgical repair (acyanotic patients) were eligible for inclusion. A single intravenous dose of acetaminophen (15 mg/kg) was administered at the start of sternal closure after separation from cardiopulmonary bypass. The time-course of acetaminophen concentrations were described using non-linear mixed effects models. One and two-compartment disposition models with first-order elimination were tested. Pharmacokinetic parameter estimates were scaled using allometry and standardized to a 70 kg person. RESULTS: There were 208 acetaminophen concentrations assayed from 30 children, 15 with cyanotic, and 15 with acyanotic heart disease. A 2-compartment model best described acetaminophen PK. Parameter estimates (population parameter variability, PPV%; 95% confidence interval, CI) were clearance CL 15.3 L.h-1.70 kg-1 (22.2%; 13.8-16.7), intercompartment clearance Q 45.4 L.h-1.70 kg-1 (22.4%; 25.2-61.9), central volume of distribution V1 33.5 L.70 kg-1 (23.2%; 25.9-38.8), peripheral volume of distribution V2 32.1 L.70 kg-1 (21.7%; 25.9-38.8). Neither clearance nor volume parameters differed between cyanotic and acyanotic patients. CONCLUSIONS: Acetaminophen pharmacokinetics were characterized using a 2-compartment model with first-order elimination following cardiac bypass surgery in children. Population pharmacokinetic parameter estimates were similar to other studies in children. No differences were detected between patients with cyanotic and acyanotic heart disease.

Cardiac Risk Factors and Complications After Spinal Fusion for Idiopathic Scoliosis in Children.

BACKGROUND: Cardiac risk factors pose challenges in pediatric posterior spinal fusion (PSF). Differences in risk according to etiology of cardiac disease are unclear. We investigated outcomes of PSF according to presence of congenital heart defect compared to cardiomyopathy. METHODS: Elective PSF for idiopathic scoliosis in patients aged 0-18 y was identified in the 2012-2015 National Surgical Quality Improvement Program-Pediatric. Cardiac risk factors were classified as: no cardiac risk factors or minor cardiac risk factors without congenital heart defect; minor cardiac risk factors because of congenital heart defect; major cardiac risk factors because of congenital heart defect; major cardiac risk factors because of cardiomyopathy. Multivariable logistic regression compared surgical site infection, wound dehiscence, hospital length of stay ≥30 d, and unplanned readmission across these categories. RESULTS: The analysis included 5395 girls and 1691 boys, aged 14 ± 2 y. Among these, 140 patients had minor cardiac risk factors because of congenital heart defect, 144 had major cardiac risk factors because of congenital heart defect, and 20 had major cardiac risk factors because of cardiomyopathy. Rates of any complication were significantly higher among patients with cardiomyopathy (40%) compared to patients with major cardiac risk factors because of congenital heart defect (10%), minor cardiac risk factors because of congenital heart defect, or other minor or no cardiac risk factors (5%; chi-square P < 0.001). In multivariable analysis of 6829 patients, cardiomyopathy predicted greater odds of unplanned readmission compared to no or minor cardiac risk factors (OR = 5.9; 95% CI: 1.8, 19.7; P = 0.004) and compared to major cardiac risk factors because of congenital heart defect (OR = 4.5; 95% CI: 1.1, 17.6; P = 0.032). CONCLUSIONS: Cardiomyopathy is a rare but significant risk factor for complications after pediatric PSF, whereas congenital heart defects did not independently contribute to risk of complications after this procedure.

Pectoralis blocks for insertion of an implantable cardioverter defibrillator in two patients with Duchenne muscular dystrophy.

Patients with Duchenne muscular dystrophy (DMD) often have systemic manifestations with comorbid involvement of the cardiac and respiratory systems that increase the risk of anesthetic and perioperative morbidity. These patients frequently develop progressive myocardial involvement with cardiomyopathy, depressed cardiac function, and arrhythmias. The latter may necessitate the placement of an automatic implantable cardioverter defibrillator (AICD) insertion. As a means of avoiding the need for general anesthesia and its inherent potential of morbidity, regional anesthesia may be used in specific cases. We present two cases of successful AICD insertion in patients with DMD using unilateral pectoralis and intercostal nerve blocks supplemented with intravenous sedation. Relevant anatomy for this regional anesthetic technique is reviewed and benefits of this anesthetic technique compared to general anesthesia are discussed.

Helium-oxygen mixture to facilitate ventilation in patients with bronchiolitis obliterans syndrome after lung transplantation.

A combination of helium and oxygen (heliox) can facilitate gas exchange and limit peak inspiratory pressures through reduced resistance to gas flow and decreased turbulent flow. The combination of these gases has been used for a variety of upper and lower airway conditions, including patients who were spontaneously breathing, receiving noninvasive ventilation, as well as during mechanical ventilation. To date, there are no reports regarding the use of heliox in patients with bronchiolitis obliterans syndrome following lung transplantation. We report the use of such a combination of gases in 2 patients with bronchiolitis obliterans syndrome following lung transplantation as a supportive measure to facilitate ventilation during the initial treatment course for acute respiratory failure in the ICU. A heliox mixture was administered with noninvasive ventilation and with mechanical ventilation through the ventilator in a heart-lung transplant recipient and a lung transplant recipient, respectively.

Abdominal compartment syndrome contributing to failure of extracorporeal membrane oxygenation in an infant with congenital heart disease and sepsis.

OBJECTIVE: To provide the first account of extracorporeal membrane oxygenation therapy failure secondary to abdominal compartment syndrome. DESIGN: Case report. SETTING: Pediatric intensive care unit. PATIENT: A 4-month-old infant with cyanotic congenital heart disease and Escherichia coli sepsis developed abdominal distention and venous return failure on extracorporeal membrane oxygenation. INTERVENTION: Emergency cardiac catheterization and atrial septectomy were performed. MAIN RESULTS: Central venous pressure of 120 mm Hg was measured, confirming the diagnosis of abdominal compartment syndrome. CONCLUSIONS: Abdominal compartment syndrome is a life-threatening condition resulting from an increase in intra-abdominal pressure that compromises abdominal organ perfusion, pulmonary function, and cardiac output. Mortality rates from abdominal compartment syndrome are as high as 60% in adults and children. This report of an infant with congenital heart disease and E. coli sepsis represents the first description of abdominal compartment syndrome that contributed to failure of extracorporeal membrane oxygenation and ultimately death. The pathophysiology, diagnosis, and treatment of abdominal compartment syndrome are also reviewed.