Neuromonitoring Modalities in Pediatric Cardiac Anesthesia: A Review of the Literature.

Recent decades have witnessed incredible developments in the care of children with congenital heart disease (CHD), such that survival into adulthood is the expected outcome. Improved survival has shifted the focus from improvements in mortality to improvements in morbidity, with long-term neurologic sequelae among the most important. Children with CHD who undergo corrective procedures in infancy and early childhood have a high rate of neurodevelopmental disability later in childhood. Impaired neurocognition is a result of many factors, including prenatal brain injury; preoperative hemodynamic derangements; exposure to anesthetic drugs; and the abnormal physiological states associated with cardiopulmonary bypass, low-flow perfusion, and deep hypothermic circulatory arrest. The intraoperative period presents a challenge to the anesthesiologist because this is a vulnerable period for the neurologic system. Transcranial Doppler ultrasound, electroencephalography, near-infrared spectroscopy, and processed electroencephalography are the neuromonitoring modalities that may be used intraoperatively. Even though each modality has merits, no single modality is able to reliably guide changes to management that improve neurologic outcomes. The best strategy is likely a multimodal neurologic monitoring strategy, although the combination of monitoring may depend on local resources and patient risk factors. This review provides a brief overview of the current knowledge regarding neurodevelopmental outcomes in children with CHD and summarizes the evidence for the use of the following 4 neuromonitoring modalities: transcranial Doppler, cerebral near-infrared spectroscopy, standard electroencephalography, and processed electroencephalography.

The effect of intraoperative methadone during pediatric cardiac surgery on postoperative opioid requirements.

BACKGROUND: Pain control in pediatric patients undergoing cardiac surgery presents a unique challenge. Postoperatively, many of these patients require long-term opioid infusions and sedation leading to need for prolonged weaning from opioids and longer hospital stays. We hypothesized that intravenous methadone as the sole opioid in children having cardiac surgery with cardiopulmonary bypass would improve perioperative pain control and decrease overall perioperative use of opioid analgesics and sedatives. METHODS: We instituted a practice change involving pediatric patients aged <18 years who underwent cardiac surgery with cardiopulmonary bypass over a 14-month period, comparing the patient population who had surgery prior to the institution of intraoperative methadone usage to patients who had surgery in the months following. We then separated patients into two groups: neonatal (aged < 30 days) and non-neonatal (aged > 30 days to 18 years). Our primary outcome was intraoperative and postoperative opioid requirements measured in morphine equivalents intraoperatively, during the first 24 hours postoperatively, and up to postoperative day 7. Secondary outcomes included extubation rates in the OR, pain and sedation scores, sedation requirements, and time to start of oxycodone. RESULTS: Patients in both groups had similar demographics. In neonatal patients, the postintervention group required significantly lower doses of intraoperative opioids. There was no statistically significant difference in postoperative opioid use. In non-neonatal patients, the postintervention group required significantly less intraoperative opioids. Postoperatively, those in the postintervention group required significantly less opioids in the first 24 hours. CONCLUSION: The use of intraoperative methadone appears to be a reasonable alternative to the use of fentanyl with potential other benefits both intra- and postoperatively of decreased total dose of opioids and other sedatives. Future studies will assess for any improvement in total postoperative opioid requirements during the total hospital stay, and potential use of methadone by the ICU team.

Pediatric Transfusion Algorithms: Coming to a Cardiac Operating Room Near You.

Pediatric cardiac surgical patients are at particular risk for post-cardiopulmonary bypass hemorrhage. Moreover, both the incidence and volume of blood transfusions have been associated with increased morbidity in pediatric cardiac patients. Transfusion of red blood cells, platelets, and coagulation factors is necessary to combat the hemodilution associated with cardiopulmonary bypass and to treat postoperative bleeding. We are challenged to apply new pharmacologic, extracorporeal, and laboratory testing advances in an evidence-based, systemic fashion to allow for appropriate transfusion. Transfusion algorithms may aid in this process, but current evidence for efficacy of transfusion algorithms in this population is limited to single-center studies. Development of a transfusion algorithm for the pediatric cardiac population requires individualization at both the institutional level, considering local resources, equipment, and case mix, and the patient level, considering age, cardiac diagnosis, and planned procedure, at minimum. A growing body of literature suggests that application of appropriate intraoperative testing (platelet count, fibrinogen concentration, thromboelastometry) along with recognition of risk factors for bleeding, adequate bypass anticoagulation, and judicious use of factor concentrates allows for thoughtful transfusion and potentially improved outcomes in pediatric cardiac patients. This review examines the evolution of transfusion algorithms in pediatric cardiac surgery and examines the considerations involved in building an algorithm for this challenging, heterogenous population.

Double-Blind, Randomized, Placebo-Controlled Trial Comparing the Effects of Antithrombin Versus Placebo on the Coagulation System in Infants with Low Antithrombin Undergoing Congenital Cardiac Surgery.

OBJECTIVES: To determine whether precardiopulmonary bypass (CPB) normalization of antithrombin levels in infants to 100% improves heparin sensitivity and anticoagulation during CPB and has beneficial effects into the postoperative period. DESIGN: Randomized, double-blinded, placebo-controlled prospective study. SETTING: Multicenter study performed in 2 academic hospitals. PARTICIPANTS: The study comprised 40 infants younger than 7 months with preoperative antithrombin levels <70% undergoing CPB surgery. INTERVENTIONS: Antithrombin levels were increased with exogenous antithrombin to 100% functional level intraoperatively before surgical incision. MEASUREMENTS AND MAIN RESULTS: Demographics, clinical variables, and blood samples were collected up to postoperative day 4. Higher first post-heparin activated clotting times (sec) were observed in the antithrombin group despite similar initial heparin dosing. There was an increase in heparin sensitivity in the antithrombin group. There was significantly lower 24-hour chest tube output (mL/kg) in the antithrombin group and lower overall blood product unit exposures in the antithrombin group as a whole. Functional antithrombin levels (%) were significantly higher in the treatment group versus placebo group until postoperative day 2. D-dimer was significantly lower in the antithrombin group than in the placebo group on postoperative day 4. CONCLUSION: Supplementation of antithrombin in infants with low antithrombin levels improves heparin sensitivity and anticoagulation during CPB without increased rates of bleeding or adverse events. Beneficial effects may be seen into the postoperative period, reflected by significantly less postoperative bleeding and exposure to blood products and reduced generation of D-dimers.

Percutaneous endoscopic gastrostomy vs surgical gastrostomy in infants with congenital heart disease.

BACKGROUND: Infants with congenital heart disease often require feeding tube placement to supplement oral intake. Gastrostomy tubes may be placed by either surgical or percutaneous endoscopic methods, but there is currently no data comparing outcomes of these procedures in this population. AIMS: The aim of our retrospective study was to investigate the perioperative outcomes between the 2 groups to determine if there are clinically significant differences. METHODS: We reviewed the charts of all infants with congenital heart disease at a single academic institution having isolated surgical or percutaneous endoscopic gastrostomy tube placement from January 2011 to December 2015. Anesthetic time, defined by cumulative minimum alveolar concentration hours of exposure to volatile anesthetic, was the primary outcome. Operative time, intraoperative complications, and postoperative intensive care admissions were secondary outcomes. RESULTS: One hundred and one infants with congenital heart disease were included in this study. Anesthetic exposure was shorter in the endoscopic group than the surgical group (0.20 MAC-hours vs 0.56 MAC-hours, 95% confidence interval 0.23, 0.49, P < .001). Average operative times were also shorter in the endoscopic gastrostomy vs the surgical group (8 ± 0.7 minutes vs 35 ± 1.3 minutes, 95% confidence interval 23.7, 31.0, P < .001). Adjusting for prematurity and preoperative risk category, the surgical group was associated with a 3.45 fold increase in the likelihood of a higher level of care postoperatively (95% confidence interval 1.20, 9.90, P = .02). CONCLUSION: In infants with congenital heart disease, percutaneous endoscopic gastrostomy placement is associated with reduced anesthetic exposure and fewer postoperative intensive care unit admissions compared to surgical gastrostomy.

Natural history of nonimmune-mediated thrombocytopenia and acute kidney injury in pediatric open-heart surgery.

OBJECTIVE: Thrombocytopenia and acute kidney injury (AKI) are common following pediatric cardiac surgery with cardiopulmonary bypass (CPB). However, the relationship between postoperative nadir platelet counts and AKI has not been investigated in the pediatric population. Our objective was to investigate this relationship and examine independent predictors of AKI. DESIGN: After IRB approval, we performed a retrospective review of the institution's medical records and database. SETTING: This study was performed at a single institution over a 5-year period. PATIENTS: We included patients <21 years of age undergoing cardiac surgery with CPB. INTERVENTIONS: Demographics, laboratory, and surgical characteristics were captured, and clinical event rates were recorded. MEASUREMENTS: Descriptive statistics were used to evaluate platelet and creatinine distributions. T-tests and chi-squared tests were used to compare characteristics among Acute Kidney Injury Network groups. Multivariable logistic and ordinal logistic regression models were used to determine the association of our predictor of interest, postoperative nadir platelet count and AKI. RESULTS: Eight hundred and fourteen patients (23% infants and 23% neonates) were included in the analysis. Postoperative platelet counts decreased 48% from baseline reaching a mean nadir value of 150 × 109 ·l-1 on postoperative day 3. AKI occurred in 37% of patients including 13%, 17%, and 6% with Acute Kidney Injury Network stages 1, 2, and 3, respectively. The magnitude of nadir platelet counts correlated with the severity of AKI. Independent predictors of severity of AKI include nadir platelet counts, CPB time, Aristotle score, patient weight, intra-operative packed red blood cell transfusion, and having a heart transplant procedure. CONCLUSIONS: In pediatric open-heart surgery, thrombocytopenia and AKI occur commonly following CPB. Our findings show a strong association between nadir platelet counts and the severity of AKI.

Reduction in blood transfusion in a cohort of infants having cardiac surgery with cardiopulmonary bypass after instituting a goal-directed transfusion policy.

BACKGROUND: Current trends in pediatric cardiac surgery and anesthesiology include goal-directed allogeneic blood transfusion, but few studies address the transfusion of platelets and cryoprecipitate. We report a quality improvement initiative to reduce the transfusion of platelets and cryoprecipitate in infants having cardiac surgery with cardiopulmonary bypass (CPB). METHODS: Data from 50 consecutive patients weighing four to ten kilograms having cardiac surgery with CPB were prospectively collected after the institution of a policy to obtain each patient's platelet and fibrinogen levels during the rewarming phase of CPB. Data from 48 consecutive patients weighing four to ten kilograms having cardiac surgery with CPB prior to the implementation of the policy change were retrospectively collected. Demographics, laboratory values and blood product transfusion data were compared between the groups, using the Chi-square/Fisher's exact test or the T-Test/Wilcoxon Rank-Sum test, as appropriate. RESULTS: The results showed more total blood product exposures in the control group during the time from bypass through the first twenty-four post-operative hours (median of 2 units versus 1 unit in study group, p=0.012). During the time period from CPB separation through the first post-operative day, 67% of patients in the control group received cryoprecipitate compared to 32% in the study group (p=0.0006). There was no difference in platelet exposures between the groups. CONCLUSION: Checking laboratory results during the rewarming phase of CPB reduced cryoprecipitate transfusion by 50%. This reproducible strategy avoids empiric and potentially unnecessary transfusion in this vulnerable population.

A change in anticoagulation monitoring improves safety, reduces transfusion, and reduces costs in infants on cardiopulmonary bypass.

BACKGROUND: An immature coagulation system coupled with the hypothermia and hemodilution associated with cardiopulmonary bypass (CPB) in infants makes the activated clotting time (ACT) an ineffective monitor for anticoagulation in this population. The Medtronic HMS Plus Hemostasis Management System (HMS; Medtronic, Inc., Minneapolis, MN, USA) is shown to decrease thrombin generation and blood product requirements. AIM: We conducted a quality improvement initiative to test our hypothesis that the use of HMS results in reduced incidence of subtherapeutic ACT values, blood product usage, and operating room time for infants undergoing cardiac surgery. METHODS: Fifty consecutive patients weighing <10 kg having cardiac surgery requiring CPB had anticoagulation managed by the HMS. Data were compared to that of 50 consecutive patients weighing <10 kg having cardiac surgery who had their anticoagulation monitored by the ACT alone. Comparisons between categorical variables were performed with chi-square tests. Comparisons between continuous variables were performed with the Wilcoxon rank-sum test. Statistical significance was defined as two-tailed P value < 0.05. RESULTS: The HMS group had a 61% decrease in incidence of ACT values <480 s and elimination of ACT values < 400 s at any time on bypass. The HMS group received fewer blood products and spent fewer minutes in the operating room after protamine administration, translating to fewer donor exposures and a savings of $403 in transfusion costs and $440 in operating room time costs. CONCLUSION: Our findings highlight the benefits of individualized heparinization for pediatric patients undergoing CPB with a monitored heparinization system.