Margaret A. Priestley

Interdisciplinary ICU Cardiac Arrest Debriefing Improves Survival Outcomes

Objective:In-hospital cardiac arrest is an important public health problem. High-quality resuscitation improves survival but is difficult to achieve. Our objective is to evaluate the effectiveness of a novel, interdisciplinary, postevent quantitative debriefing program to improve survival outcomes after in-hospital pediatric chest compression events. Design, Setting, and Patients:Single-center prospective interventional study of children who received chest compressions between December 2008 and June 2012 in the ICU. Interventions:Structured, quantitative, audiovisual, interdisciplinary debriefing of chest compression events with front-line providers. Measurements and Main Results:Primary outcome was survival to hospital discharge. Secondary outcomes included survival of event (return of spontaneous circulation for ≥ 20 min) and favorable neurologic outcome. Primary resuscitation quality outcome was a composite variable, termed “excellent cardiopulmonary resuscitation,” prospectively defined as a chest compression depth ≥ 38 mm, rate ≥ 100/min, ⩽ 10% of chest compressions with leaning, and a chest compression fraction > 90% during a given 30-second epoch. Quantitative data were available only for patients who are 8 years old or older. There were 119 chest compression events (60 control and 59 interventional). The intervention was associated with a trend toward improved survival to hospital discharge on both univariate analysis (52% vs 33%, p = 0.054) and after controlling for confounders (adjusted odds ratio, 2.5; 95% CI, 0.91–6.8; p = 0.075), and it significantly increased survival with favorable neurologic outcome on both univariate (50% vs 29%, p = 0.036) and multivariable analyses (adjusted odds ratio, 2.75; 95% CI, 1.01–7.5; p = 0.047). Cardiopulmonary resuscitation epochs for patients who are 8 years old or older during the debriefing period were 5.6 times more likely to meet targets of excellent cardiopulmonary resuscitation (95% CI, 2.9–10.6; p < 0.01). Conclusion:Implementation of an interdisciplinary, postevent quantitative debriefing program was significantly associated with improved cardiopulmonary resuscitation quality and survival with favorable neurologic outcome.

Regional patterns of neuronal death after deep hypothermic circulatory arrest in newborn pigs

OBJECTIVES Deep hypothermic circulatory arrest (DHCA) widely used during neonatal heart surgery, carries a risk of brain damage. In adult normothermic ischemia, brain cells in certain regions die, some by necrosis and others by apoptosis (programmed cell death). This study characterized regional brain cell death after DHCA in newborn pigs. METHODS Eighteen piglets underwent 90 minutes of DHCA and survived 6 hours, 2 days, or 1 week. Six piglets underwent surgery alone or deep hypothermic cardiopulmonary bypass and survived 2 days. Three piglets received no intervention (control). Brain injury was assessed by neurologic and histologic examination and correlated with perioperative factors. Apoptosis and necrosis were identified by light microscopic analysis of cell structure and in situ DNA fragmentation (TUNEL). RESULTS All groups subjected to DHCA had brain injury by neurologic and histologic examination, whereas the other groups did not. DHCA damaged neurons in the neocortex and hippocampus and occasionally in the striatum and cerebellum. Damaged neurons in the neocortex were mainly apoptotic and in the hippocampus, a mixture of necrotic and apoptotic neurons. Apoptosis and necrosis were apparent in all DHCA groups even though neurologic deficits improved over the weeks survival. Neocortical and hippocampal damage correlated with blood glucose, hematocrit, and arterial PO(2) during and after cardiopulmonary bypass. CONCLUSIONS In neonates, neocortical and hippocampal neurons are selectively vulnerable to death after DHCA. Both apoptosis and necrosis contribute to neuronal death, beginning early in reperfusion and continuing for days. These data suggest the need for several neuroprotective strategies tailored to the region and death process, initiated during the operation and continued after the operation.

Extracorporeal membrane oxygenation after stage I reconstruction for hypoplastic left heart syndrome

Objective: Although extracorporeal membrane oxygenation (ECMO) is an acceptable strategy for children with refractory cardiac dysfunction after cardiac surgery, its role after stage I reconstruction for hypoplastic left heart syndrome and its variants is controversial. Our objective is to describe the outcome of “nonelective” ECMO after stage I reconstruction. Design: Retrospective case series. Setting: Pediatric cardiac intensive care unit. Patients: Infants placed on ECMO after stage I reconstruction from January 1998 to May 2005. Interventions: None. Measurements and Main Results: Of the 382 infants who underwent stage I reconstruction during the study period, 36 (9.4%) required ECMO in the postoperative period. There were 22 infants with hypoplastic left heart syndrome. Indications for ECMO included inability to separate from cardiopulmonary bypass in 14 and cardiac arrest in 22. Fourteen infants (38.8%) survived to hospital discharge. Nonsurvivors had longer cardiopulmonary bypass time (150.1 ± 70.0 mins vs. 103.9 ± 30.0 mins, p =. 01). 9/14 infants (64%) supported with ECMO> than 24 hrs after stage I reconstruction survived while only 5/22 infants (22%) requiring ECMO< 24 hrs of stage I reconstruction survived (p =. 02). Of note, all five infants diagnosed with an acute shunt thrombosis were early survivors. Mean duration of ECMO was 50.1 ± 12.5 hrs for survivors and 125.2 ± 25.0 for nonsurvivors (p =. 01). 7/14 early survivors are alive at a median follow-up of 20 months (2–78 months). Conclusions: In our experience, ECMO after stage I reconstruction can be life saving in about a third of infants with otherwise fatal conditions. It is particularly useful in potentially reversible conditions such as acute shunt thrombosis and transient depression of ventricular function.

Desflurane Improves Neurologic Outcome after Low-flow Cardiopulmonary Bypass in Newborn Pigs

Background Despite improvements in neonatal heart surgery, neurologic complications continue to occur from low-flow cardiopulmonary bypass (LF-CPB) and deep hypothermic circulatory arrest (DHCA). Desflurane confers neuroprotection against ischemia at normothermia and for DHCA. This study compared neurologic outcome of a desflurane-based with a fentanyl-based anesthetic for LF-CPB. Methods Thirty piglets aged 1 week received either fentanyl–droperidol (F/D), desflurane 4.5% (Des4.5), or desflurane 9% (Des9) during surgical preparation and CPB. Arterial blood gases, glucose, heart rate, arterial pressure, brain temperature, and cerebral blood flow (laser Doppler flowmetry) were recorded. After CPB cooling (22°C brain) using pH-stat strategy, LF-CPB was performed for 150 min followed by CPB rewarming, separation from CPB, and extubation. On postoperative day 2, functional and histologic outcomes were assessed. Results Cardiovascular variables were physiologically similar between groups before, during, and after LF-CPB. Cerebral blood flow during LF-CPB (13% of pre-CPB value) did not differ significantly between the groups. Functional disability was worse in F/D than in Des9 (P = 0.04) but not Des4.5 (P = 0.1). In neocortex, histopathologic damage was greater in F/D than in Des4.5 (P = 0.03) and Des9 (P = 0.009). In hippocampus, damage was worse in F/D than in Des9 (P = 0.01) but not Des4.5 (P = 0.08). The incidences of ventricular fibrillation during LF-CPB were 90, 60, and 10% for F/D, Des4.5 (P = 0.06), and Des9 (P = 0.0002), respectively. Conclusions Desflurane improved neurologic outcome following LF-CPB compared with F/D in piglets, indicated by less functional disability and less histologic damage, especially with Des9. Desflurane may have produced cardiac protection, suggested by a lower incidence of ventricular fibrillation.

Apoptotic Neuronal Death following Deep Hypothermic Circulatory Arrest in Piglets

Background Deep hypothermic circulatory arrest (DHCA), as used in infant heart surgery, carries a risk of brain injury. In a piglet DHCA model, neocortical neurons appear to undergo apoptotic death. Caspases, cytochrome c, tumor necrosis factor (TNF), and Fas play a role in apoptosis in many ischemic models. This study examined the expression of these factors in a DHCA piglet model. Methods Thirty-nine anesthetized piglets were studied. After cardiopulmonary bypass (CPB) cooling of the brain temperature to 19°C, DHCA was induced for 90 min, followed by CPB rewarming. After separation from CPB, piglets were killed at 1, 4, 8, 24, and 72 h and 1 week. Caspase-8 and -3 activity, and concentrations of TNF-&agr;, Fas, Fas-ligand, cytochrome c, and adenosine triphosphate (ATP) were measured in the neocortex by enzymatic assay and Western blot analysis. Caspase-8 and -3 activity and cell death were examined histologically. Significance was set at P < 0.05. Results In neocortex, damaged neurons were not observed in control (no CPB), rarely observed in CPB (no DHCA), and rarely observed in the DHCA 1-h, 4-h, and 1-week reperfusion groups. However, they were seen frequently in the DHCA 8-, 24-, and 72-h reperfusion groups. Although neuronal death was widespread 8–72 h after DHCA, cortical ATP concentrations remained unchanged from control. Both caspase-3 and -8 activities were significantly increased at 8 h after DHCA, and caspase-3 concentration remained elevated for as long as 72 h. Caspase-3 and -8 activity was also observed in damaged neocortical neurons. Cytosolic cytochrome c and Fas were significantly expressed at 1 h and 4 h after DHCA, respectively. Fas-ligand and TNF-&agr; were not observed in any group. Conclusion After DHCA, induction of apoptosis in the neocortex occurs within a few hours of reperfusion and continues for several days. Increased Fas, cytochrome c, and caspase concentrations, coupled with normal brain ATP concentrations and apoptotic histologic appearance, are consistent with the occurrence of apoptotic cell death.

Airway pressure release ventilation in pediatrics

Objectives The purpose of this study was to determine the effectiveness of airway pressure release ventilation in children. Design Prospective, randomized, crossover clinical trial. Setting This study was conducted in our 33-bed pediatric intensive care unit at The Children’s Hospital of Philadelphia. Patients Patients requiring mechanical ventilatory support and weighing >8 kg were considered for enrollment. Patients were excluded if they required mechanical ventilatory support for >7 days or required >.50 Fio2 for >7 days before enrollment. Patients with documented obstructive airway disease and congenital or acquired heart disease were excluded as well. Interventions Each patient received both volume-controlled synchronized intermittent mechanical ventilation (SIMV) and airway pressure release ventilation (APRV) via the Drager Evita ventilator (Drager, Lubeck, Germany). Measurements were obtained after the patient was stabilized on each ventilation mode. Stabilization was defined as oxygenation, ventilation, hemodynamic variables, and patient comfort within the acceptable range for each patient as determined by the bedside physician. After measurements were obtained on the initial mode of ventilation, the subjects crossed over to the alternative study mode. Stabilization was again achieved, and measurements were repeated. After completion of the second study measurements, patients were placed on the ventilation modality preferred by the bedside clinician and were followed through weaning and extubation. Measurements Vital signs, airway pressures, minute ventilation, Spo2, and ETCO2 were recorded at enrollment and at each study condition. Main Results APRV provided similar ventilation, oxygenation, mean airway pressure, hemodynamics, and patient comfort as SIMV. Inspiratory airway pressures were lower with APRV when compared with SIMV. Conclusions Using APRV in children with mild to moderate lung disease resulted in comparable levels of ventilation and oxygenation at significantly lower inspiratory peak and plateau pressures. Based on these findings, we plan to evaluate APRV in children with significant lung disease.

Desflurane confers neurologic protection for deep hypothermic circulatory arrest in newborn pigs

BackgroundCardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA), as used for infant heart surgery, carry a risk of ischemic neurologic injury. Volatile anesthetics have neuroprotective properties against both global and focal ischemia at normothermia. The authors examined the hemodynamic and neuroprotective effects of desflurane in a piglet CPB–DHCA model. MethodsTwenty piglets aged 5–10 days received a desflurane- (6–9% expired) or fentanyl-based anesthetic before and during CPB (before and after DHCA). DHCA lasted 90 min at 19°C brain. Cardiovascular variables (heart rate, arterial pressure, blood gases, glucose, brain temperature) were monitored. On postoperative day 2, neurologic and histologic outcomes were determined. ResultsCardiovascular variables before, during, and after CPB were physiologically similar between groups. The desflurane group had better neurologic performance (P = 0.023) and greater postoperative weight gain (P = 0.04) than the fentanyl group. In neocortex, the desflurane group had less tissue damage (P = 0.0015) and fewer dead neurons (P = 0.0015) than the fentanyl group. Hippocampal tissue damage was less in the desflurane group (P = 0.05), but overall, neuronal cell counts in the CA1 sector of the right hippocampus were similar to those in the fentanyl group. ConclusionsDesflurane-based anesthesia yields hemodynamics during CPB with DHCA that are similar to those with fentanyl-based anesthesia. However, desflurane-based anesthesia improves neurologic and histologic outcomes of CPB–DHCA in comparison with outcomes with fentanyl-based anesthesia.

Critical heart disease in the neonate: Presentation and outcome at a tertiary care center

Objective: To define the modes of presentation, incidence of major organ dysfunction, predictors of hospital mortality, and adverse outcomes in neonates with critical heart disease admitted to a tertiary care center. Design: Retrospective chart review. Setting: A tertiary care pediatric cardiac intensive care unit and neonatal intensive care unit. Patients: The medical records for all neonates (≤30 days of age) with heart disease admitted to the cardiac intensive care unit or neonatal intensive care unit between October 1, 2002, and September 30, 2003, were reviewed. Interventions: None. Measurements and Main Results: A total of 190 neonates met inclusion criteria during this 1-yr period, of which 146 (77%) had at least one surgical procedure. Single ventricle heart disease was present in 42%. The most common mode of presentation was following a prenatal diagnosis (53%), followed by diagnosis in the newborn nursery (38%) and diagnosis after newborn hospital discharge (8%). The most common presenting findings in the newborn nursery were isolated murmur (38%) or cyanosis (32%), while circulatory collapse (38%) was the most common presentation after discharge. For the entire study cohort, 13% had a known genetic syndrome, 23% had a major noncardiac congenital anomaly, and 16% weighed <2.5 kg. The hospital mortality for the entire cohort was 7.4%. Risk factors associated with an increased risk of hospital mortality included younger age at admission, higher number of cardiopulmonary bypass runs, and need for postoperative cardiopulmonary resuscitation. Total hospital length of stay was >1 month in 17% of neonates. Conclusions: In patients with complex congenital heart disease, including nearly half with single ventricle heart disease, neonatal hospital mortality was 7%. These patients have a high frequency of multiple congenital anomalies, genetic syndromes, low birth weight, and prolonged length of stay.

Development of a Pragmatic Measure for Evaluating and Optimizing Rapid Response Systems

OBJECTIVES: Standard metrics for evaluating rapid response systems (RRSs) include cardiac and respiratory arrest rates. These events are rare in children; therefore, years of data are needed to evaluate the impact of RRSs with sufficient statistical power. We aimed to develop a valid, pragmatic measure for evaluating and optimizing RRSs over shorter periods of time. METHODS: We reviewed 724 medical emergency team and 56 code-blue team activations in a children’s hospital between February 2010 and February 2011. We defined events resulting in ICU transfer and noninvasive ventilation, intubation, or vasopressor infusion within 12 hours as “critical deterioration.” By using in-hospital mortality as the gold standard, we evaluated the test characteristics and validity of this proximate outcome metric compared with a national benchmark for cardiac and respiratory arrest rates, the Child Health Corporation of America Codes Outside the ICU Whole System Measure. RESULTS: Critical deterioration (1.52 per 1000 non-ICU patient-days) was more than eightfold more common than the Child Health Corporation of America measure of cardiac and respiratory arrests (0.18 per 1000 non-ICU patient-days) and was associated with >13-fold increased risk of in-hospital death. The critical deterioration metric demonstrated both criterion and construct validity. CONCLUSIONS: The critical deterioration rate is a valid, pragmatic proximate outcome associated with in-hospital mortality. It has great potential for complementing existing patient safety measures for evaluating RRS performance.

Cost-Benefit Analysis of a Medical Emergency Team in a Children’s Hospital

OBJECTIVES: Medical emergency teams (METs) can reduce adverse events in hospitalized children. We aimed to model the financial costs and benefits of operating an MET and determine the annual reduction in critical deterioration (CD) events required to offset MET costs. METHODS: We performed a single-center cohort study between July 1, 2007 and March 31, 2012 to determine the cost of CD events (unplanned transfers to the ICU with mechanical ventilation or vasopressors in the 12 hours after transfer) as compared with transfers to the ICU without CD. We then performed a cost-benefit analysis evaluating varying MET compositions and staffing models (freestanding or concurrent responsibilities) on the annual reduction in CD events needed to offset MET costs. RESULTS: Patients who had CD cost