The correlation of fluid balance changes during cardiopulmonary bypass to mortality in pediatric and congenital heart surgery patients.

Edema acquired during the perioperative period has long been associated with increased mortality. Edema acquired during cardiopulmonary bypass (CPB) may contribute to this mortality. The intent of this retrospective study was to test the premise that edema in the form of a positive fluid balance change (FBC) acquired during CPB correlated to mortality. If so, FBC from the beginning of CPB (baseline; FBC = 0) to the end of CPB may need to be monitored, measured, and controlled on CPB with the same ardor as blood pressure and pH. This retrospective analysis reviewed the FBC of 1540 pediatric and congenital heart surgery patients at the end of CPB. Additions and subtractions of fluid to the combined patient/CPB circuit were routinely quantified during CPB procedures and during periods of modified ultrafiltration (MUF). The primary outcome assessed was mortality during hospitalization. The overall mortality of the 1540 patients was 5.65% from all causes. Eighty percent (n = 1226, mortality = 4.65%) of the patients had a zero or negative FBC immediately after CPB/MUF. Twenty percent (n = 314, mortality = 9.55%) had a positive FBC. Positive FBC patients tended to be in higher risk categories, weighed more, and had longer pump times (p < .05) with an adjusted odds ratio for mortality of 1.73 (1.01-2.96, 95% confidence interval). There is a correlation between edema acquired during CPB and increased mortality in pediatric and congenital heart surgery patients. The potential exists for the perfusionist to optimize the fluid balance changes while on CPB to reduce mortality rates.

Identifying neonatal and pediatric cardiac and congenital diaphragmatic hernia extracorporeal membrane oxygenation patients at increased mortality risk.

UNLABELLED: A previous review from our institution established clinically measured cut-points that defined the late implementation of extracorporeal membrane oxygenation (ECMO) correlating to increased mortality in neonatal and pediatric respiratory patients. Using the same methods, this review evaluates pediatric and neonatal cardiac and congenital diaphragmatic hernia (CDH) patients to determine if the same cut-points exist in this higher risk patient population. Neonatal and pediatric cardiac and CDH patients placed on ECMO between November 1989 and December 2008 were retrospectively reviewed to determine the first adjusted anion gap (AGc), the first venoarterial carbon dioxide (CO2) gradient (p[v-a]CO2), and the first Viability Index (AGc + p[v-a]CO2 = INDEX) on ECMO. These markers were then analyzed to identify the presence of specific cut-points that marked an increased risk of mortality. The timing of surgery was also reviewed to assess the surgical morbidity on survival. The review of neonatal and pediatric cardiac and CDH patients (n = 205) with an overall survival of 46% showed that all three markers were elevated to varying degrees in the expired patients (n = 110). Histograms identified the following specific cut-points for increased mortality: the AGc > or = 23 mEq/L, the p[v-a]CO2 _ 16 mmHg, and the INDEX > or = 28. An elevated AGc and INDEX correlated with a significantly higher risk for mortality (p < .05), survival to discharge being 20% or less. Patients under the cut-points had survival rates of 51% or higher. The timing of surgery (before or after ECMO initiation) did not significantly impact survival in the combined cardiac and CDH group. An INDEX > or = 28 correlates with non-survival. We speculate that the late implementation of ECMO may lead to reperfusion injury, which causes reduced survival, and that ECMO intervention prior to reaching the cut-points may improve survival in neonatal and pediatric cardiac and CDH patients. KEYWORDS: cardiac, congenital, diaphragmatic, extracorporeal membrane oxygenation, neonate, pediatric.

Pediatric cardiopulmonary bypass adaptations for long-term survival of baboons undergoing pulmonary artery replacement.

Cardiopulmonary bypass (CPB) protocols of the baboon (Papio cynocephalus anubis) are limited to obtaining experimental data without concern for long-term survival. In the evaluation of pulmonary artery tissue engineered heart valves (TEHVs), pediatric CPB methods are adapted to accommodate the animals' unique physiology enabling survival up to 6 months until elective sacrifice. Aortic access was by a 14F arterial cannula and atrial access by a single 24F venous cannula.The CPB circuit includes a 3.3 L/min flow rated oxygenator, 1/4" x %" arterial-venous loop, 3/8" raceway, and bubble trap. The prime contains 700 mL Plasma-Lyte, 700 units heparin, 5 mL of 50% dextrose, and 20 mg amiodarone. Heparinization (200 u/kg) targets an activated clotting time of 350 seconds. Normothermic CPB was initiated at a 2.5 L/m2/min cardiac index with a mean arterial pressure of 55-80 mmHg. Weaning was monitored with transesophageal echocardiogram. Post-CPB circuit blood was re-infused. Chest tubes were removed with cessation of bleeding. Extubation was performed upon spontaneous breathing. The animals were conscious and upright 3 hours post-CPB. Bioprosthetic valves or TEHVs were implanted as pulmonary replacements in 20 baboons: weight = 27.5 +/- 5.6 kg, height = 73 +/- 7 cm, body surface area = 0.77 m2 +/- 0.08, mean blood flow = 1.973 +/- .254 L/min, core temperature = 37.1 +/- .1 degree C, and CPB time = 60 +/- 40 minutes. No acidosis accompanied CPB. Sixteen animals survived, four expired. Three died of right ventricular failure and one of an anaphylactoid reaction. Surviving animals had normally functioning replacement valves and ventricles. Baboon CPB requires modifications to include high systemic blood pressure for adequate perfusion into small coronary arteries, careful CPB weaning to prevent ventricular distention, and drug and fluid interventions to abate variable venous return related to a muscularized spleno-splanchnic venous capacity.

Defining the late implementation of extracorporeal membrane oxygenation (ECMO) by identifying increased mortality risk using specific physiologic cut-points in neonatal and pediatric respiratory patients.

There is no reliable clinical indicator showing how long extracorporeal membrane oxygenation (ECMO) implementation can be delayed before the risk of death becomes unacceptably high in neonatal and pediatric respiratory patients. However, the late use of ECMO may be defined by the elevation of specific physiologic markers separate from pulmonary function and hemodynamic assessments that indicate when the optimal time for implementation of ECMO has past, resulting in a higher than normal mortality, possibly due to reperfusion injury. Neonatal patients were reviewed retrospectively to determine if later implementation of ECMO correlated to increased mortality. Neonatal and pediatric respiratory patients placed on ECMO were reviewed retrospectively to determine if the first adjusted anion gap (AGc), the first venoarterial CO2 gradient (p[v-a] CO2), or the first Viability Index (AGc + p[v-a]CO2 = INDEX) on ECMO could be used to identify a cut-point for increased mortality. Expired neonates (n = 31) were placed on ECMO an average of 2 days later than neonatal survivors (n = 163). The review of 210 respiratory neonatal and pediatric ECMO patients with an overall survival of 82% showed that all three markers were elevated in the expired patients (n = 38, p < .05). Cut-points were an AGc > or = 23 mEq/L, the p[v-a]CO2 > or = 16 mmHg, and the INDEX > or = 28. These values correlated with a significantly higher risk of mortality (p < .05); survival to discharge being 43% or less. Patients under the cut-points had survival rates of 84% or higher. Starting ECMO too late may cause reperfusion injury that reduces survival. This study describes specific physiologic markers taken soon after ECMO initiation that correlate with mortality. These markers, if assessed earlier, may allow for a more timely ECMO implementation and higher survival.