Successful resolution of hyperammonemia following hematopoietic cell transplantation with directed treatment of Ureaplasma parvum infection.

Hyperammonemia following hematopoietic cell transplantation (HCT) has been characterized as idiopathic and is associated with a very high mortality. A causal relationship between Ureaplasma infection and hyperammonemia in immunocompromised lung transplant recipients has recently been described. We document the first case of hyperammonemia following HCT associated with Ureaplasma parvum. The initiation of appropriate antibiotics resulted in rapid resolution of hyperammonemic encephalopathy and eradication of the implicating organism.

Extracorporeal membrane oxygenation (ECMO) for critically ill adults in the emergency department: history, current applications, and future directions.

Extracorporeal membrane oxygenation (ECMO) is a mode of extracorporeal life support that augments oxygenation, ventilation and/or cardiac output via cannulae connected to a circuit that pumps blood through an oxygenator and back into the patient. ECMO has been used for decades to support cardiopulmonary disease refractory to conventional therapy. While not robust, there are promising data for the use of ECMO in acute hypoxemic respiratory failure, cardiac arrest, and cardiogenic shock and the potential indications for ECMO continue to increase. This review discusses the existing literature on the potential use of ECMO in critically ill patients within the emergency department.

Construction of a reusable, high-fidelity model to enhance extracorporeal membrane oxygenation training through simulation.

Initiation of extracorporeal membrane oxygenation (ECMO) is stressful, especially for inexperienced extracorporeal life support providers. The main objective of this study was to create a novel, reusable mannequin for high-fidelity simulation of ECMO initiation. We modified a Laerdal neonatal mannequin (SimNewB; Stavanger, Norway) so that it could be used to simulate an ECMO initiation. A simulation of a neonatal patient suffering from meconium aspiration was performed in the pediatric intensive care unit, and participants included new extracorporeal life support specialists in addition to the composition of the clinical ECMO team. A total of 17 individuals participated in the neonatal ECMO initiation simulation. Questionnaire results showed that 88% of participants felt better prepared to assist in an ECMO initiation after the simulation. All participants (100%) agreed that the modified mannequin and the environment were realistic and that this simulation helps teamwork and communication in future initiations of ECMO. Simulation can be used for the prevention, identification, and reduction of anxiety-related crisis situations that novice providers may infrequently encounter during routine clinical use of mechanical circulatory support. Use of a reusable, high-fidelity mannequin may be beneficial for effective team training of complex pediatric ECMO-related procedures.

Pediatric defibrillation doses often fail to terminate prolonged out-of-hospital ventricular fibrillation in children.

BACKGROUND: The recommended dose for pediatric defibrillation is 2 J/kg, based on animal studies of brief duration ventricular fibrillation (VF) and a single pediatric study of short duration in-hospital VF. In a piglet model of out-of-hospital (prolonged) cardiac arrest, this recommended dose was usually ineffective at terminating VF. We, therefore, hypothesized that pediatric dose defibrillation may be less effective for prolonged out-of-hospital pediatric VF. METHODS: We evaluated retrospectively all cardiac arrests in children less than 13 years old in Tucson from November 1998 to April 2003, with special attention to all children in ventricular fibrillation. We determined the rate of ventricular fibrillation termination after pediatric dose shocks in this cohort, and compared this rate with a published historical pediatric in-hospital defibrillation control group. A pediatric dose shock was defined as 2 J/kg (+/-10 J). All shocks in both groups were provided as monophasic damped sinusoidal waveforms. RESULTS: Thirteen of 151 (9%) children with out-of-hospital cardiac arrest had documented VF. Eleven children received a total of 14 pediatric dose shocks. The median minimum untreated dispatch-to-shock time in unwitnessed arrest or collapse-to-shock in witnessed arrest for those 11 children was 11 min (interquartile range 25-75%; 9-15.5 min). Seven of the 14 pediatric dose shocks terminated the VF (six to asystole, one to pulseless electrical activity). Nine children (68%) died in the emergency department and four (31%) in the pediatric intensive care unit; none survived to hospital discharge. Failure to terminate VF after a pediatric dose shock in this study group with prolonged out-of-hospital ventricular fibrillation was substantially more common than the previously reported in-hospital data (7/14 versus 5/57; OR 10.4; 95% CI 2.6-42; P=0.001). CONCLUSIONS: Termination of VF after a pediatric defibrillation dose is substantially worse for prolonged pediatric out-of-hospital VF cardiac arrest compared with in-hospital (short duration) ventricular fibrillation. The optimal pediatric defibrillation dose for prolonged VF is not known.

Post-resuscitation right ventricular dysfunction: delineation and treatment with dobutamine.

BACKGROUND: Left ventricular dysfunction after resuscitation from cardiac arrest has been well described. Treatment with dobutamine improves post-resuscitation left ventricular function. Right ventricular function following resuscitation has not been investigated. The purposes of this study were to examine right ventricular function following resuscitation and determine whether dobutamine would improve post-resuscitation right ventricular function. METHODS AND RESULTS: Right ventricular function was measured in 28 swine (29+/-1 kg) before and after resuscitation from 15 min of untreated ventricular fibrillation. Twelve animals received dobutamine at 10 mcg/kg/min while 16 animals served as untreated controls. Among controls, right ventricular dysfunction post-resuscitation was demonstrated by a decrease in right ventricular ejection fraction and an increase in right ventricular end-diastolic pressure. Among animals treated with dobutamine, there was a significant improvement in right ventricular function post-resuscitation compared to untreated controls. CONCLUSIONS: This study establishes that right ventricular systolic and diastolic dysfunction does occur after prolonged cardiac arrest from ventricular fibrillation. Dobutamine can ameliorate post-resuscitation right ventricular dysfunction.

Survival and renal function in pediatric patients following extracorporeal life support with hemofiltration.

OBJECTIVE: To determine variables associated with survival in pediatric patients treated with hemofiltration while receiving extracorporeal life support and to determine the probability for recovery of renal function among survivors. DESIGN: Retrospective database analysis. SETTING: University of Michigan pediatric nephrology database. PATIENTS: All pediatric patients treated with continuous hemofiltration while on extracorporeal life support at the University of Michigan between January 1990 and May 1999. A pediatric patient was defined as any child between birth and 18 yrs of age, including children treated in both the pediatric intensive care unit and neonatal intensive care unit. Indications for extracorporeal life support included both cardiac and pulmonary failure. INTERVENTIONS: Data analysis of patients who were treated with hemofiltration while on extracorporeal life support. Hemofiltration includes both ultrafiltration and hemofiltration with countercurrent dialysis. MEASUREMENTS AND MAIN RESULTS: Thirty-five patients with a mean age of 39 +/- 65 months (median, 3 months) underwent hemofiltration while on extracorporeal life support. Forty-three percent survived to hospital discharge (95% CI, 26%-60%). All deaths occurred in the intensive care unit. Recovery of renal function occurred in 93% of survivors (95% CI, 79%-108%). Mean duration of hemofiltration in survivors, including time during and after extracorporeal life support, was 9 +/- 6 days. All nonsurvivors were on renal replacement therapy at the time of death. In this analysis, decreased survival was significantly associated with the use of vasopressor infusions (p =.01) and the presence of complications (p =.006). Vasopressor infusions were required in 89% of patients, and 37% of patients experienced complications. CONCLUSIONS: In patients receiving hemofiltration while on extracorporeal life support, survival is comparable to that reported in other extracorporeal life support or hemofiltration populations. Decreased survival in these patients may be associated with the use of vasopressor infusions and the occurrence of complications. Recovery of renal function occurs in most survivors.

Pediatric extracorporeal life support after high frequency ventilation: predictors of survival.

Previous studies of extracorporeal life support in pediatric patients have identified variables associated with survival. However, none of these studies focused on extracorporeal life support after failure of high frequency ventilation (HFV). In the present study, we determined variables associated with survival for pediatric respiratory failure patients who received HFV prior to extracorporeal life support, using data reported to the Extracorporeal Life Support Organization Registry from 1992 to 1998. Patients with neonatal diagnoses, immune compromising conditions, or congenital cardiac defects were excluded. The 243 patients who met inclusion criteria had a 58% survival rate (95% CI 48-66%). The mean age was 22 +/- 39 months. Mean duration of mechanical ventilation prior to extracorporeal life support was 6.6 +/- 5.8 days. Venoarterial extracorporeal life support was used in 72% of the patients; venovenous in 28%. The survival rate for the subset of patients with an oxygenation index greater than 42 cm H2O/torr on HFV (n = 122) was not significantly different from the overall sample. We determined that lower mean airway pressure, lower pressure amplitude, decreased oxygenation index, increased PaO2, and increased oxygen saturation on HFV were associated with increased survival in patients who were subsequently treated with extracorporeal life support.

When children die: a seminar series for pediatric residents.

OBJECTIVE: Our goals were to assist residents in acquiring skills needed to care for children at the end of life and to increase their comfort level regarding critical aspects of caring for dying children. METHODS: We designed and implemented a 6-part seminar series for pediatric residents in their postgraduate year-2 at the University of Arizona Pediatric Residency Program. The series consisted of small group sessions regarding medical and legal issues facing physicians at the time of a pediatric patient's death, symptom management in dying children, approaches to limitation of care and discussion of impending death of a child, cultural and developmental factors impacting on the care of children at the end of life, parent and sibling bereavement after the death of a child, and physician's personal responses to the death of pediatric patients. The sessions were conducted on weekday evenings away from patient care settings and included input from community-based individuals as well as academic pediatric subspecialists. To promote active discussion, size was limited to 12 participants. Pretests and posttests were used to evaluate the success of this program. Residents' level of comfort with important issues in end-of-life care was measured using a 5-point Likert scale. RESULTS: Although most of the residents taking part in the seminar series had previously participated in discussions of limitation of care of a child and/or had performed advanced life support measures on a child, few had any previous training in end-of-life care. Responses of the 8 participants who completed both the pretests and posttests were evaluated for assessment of changes in comfort level in areas pertinent to end-of-life care. We found that on completion of this program, residents were significantly more comfortable with logistic issues and symptom management, discussing death and limitation of medical care with families, discussing end-of-life care with colleagues and families, handling conflicts within the health care team, working with families of varying ethnic backgrounds, guiding developmentally appropriate discussions of death, identifying and seeking out advice from a role model regarding end-of-life care, and coping with their own responses to a child's death. Costs of this seminar series were minimal. CONCLUSIONS: An inexpensive, discussion-based seminar series successfully provided pediatric residents with basic information regarding end-of-life care and significantly increased their confidence as clinicians caring for seriously ill and dying children.