The Impact of Scripted Self-Hypnotic Relaxation on the Periprocedural Experience and Anesthesiologist Sedation Use in the Pediatric Cardiac Catheterization Suite: A Prospective Randomized Controlled Trial.

Purpose: To assess the impact on children of self-hypnotic relaxation scripts read by trained staff prior to the induction of anesthesia and/or extubation on the periprocedural experience. Patients and Methods: A total of 160 children aged 7-18 years undergoing a cardiac catheterization intervention under general anesthesia were randomized into 4 groups: (1) a pre-procedure (PP-script) read prior to entering the procedural room, (2) a script read prior to extubation (PX-Script), (3) both PP- and PX-Scripts read and (4) no script read. Anxiety and pain were rated on self-reported 0-10 scales. The modified Yale Preoperative Anxiety Scale was used for preoperative anxiety. The effect of script reading was associated with outcomes by linear regression for continuous variables, and logistic regression for binary variables in two-sided tests at a significance level of 0.05. Results are given in odds ratios (OR) and 95% confidence intervals (CI). Results: Data were available for 158 patients. Reading the PP-Script prior to anesthesia was associated with a significant reduction in the use of intraoperative sedatives from 30% to 14% (OR 0.40; CI 0.18-0.88; p = 0.02) by the anesthesiologists, who were blinded to group attribution until extubation. This was despite the children not self-reporting significantly lower levels of anxiety or pain. The PX-Script did not change outcomes. Among groups, there was no significant difference in room time, postoperative recovery time and pain. Conclusion: Reading a PP-Script for guidance in self-hypnotic relaxation can result in less need for intravenous sedation in the judgment of the anesthesiologist, independent of the children's self-reported anxiety and pain. This raises interesting questions about subconscious patient-physician interactions affecting pain management. Clinicaltrialsgov Identifier: NCT02347748.

Challenges with heparin-based anticoagulation during cardiopulmonary bypass in children: Impact of low antithrombin activity.

BACKGROUND: Antithrombin is one of the main natural coagulation system inhibitors. It is potentiated by heparin, and may be a key component of heparin response, particularly in infants aged <1 year. We sought to determine the impact of baseline antithrombin activity on response to heparin and thrombin generation during cardiopulmonary bypass (CPB). METHODS: Secondary analysis was performed using linear regression analyses, which combined patients from a trial of individualized versus weight-based heparin management for 90 infants aged <1 year undergoing cardiac surgery. RESULTS: Mean baseline antithrombin activity was 0.69 ± 0.16 U/mL, and it was lower in neonates than in older infants (0.57 ± 0.15 vs 0.77 ± 0.12 U/mL; P < .001). Lower baseline antithrombin activity was associated with lower postheparin anti-Xa activity (EST [SE]: +0.47 (0.19) U/mL per 100 U/kg heparin; P = .01) and higher heparin doses during surgery (EST [SE]: +51 (17) U/kg per hour; P = .003). The administration of fresh frozen plasma attenuated the effect of low baseline antithrombin activity (interaction P value = .009). Patients with lower anti-Xa activity recorded during CPB had higher levels of thrombin-antithrombin complex (EST [SE]: +12.8 (4.7) ng/mL per -1 U/mL anti-Xa; P = .006); prothrombin activation fragment 1.2 (EST [SE]: +0.13 (0.07) log pg/mL per -1 U/mL anti-Xa; P = .06); and D-dimer (EST [SE]: -0.25 (0.09) log ng/mL per -1 U/mL anti-Xa; P = .009) in the postoperative period after adjustment for baseline antithrombin activity, duration of CPB, amount of fresh frozen plasma and heparin used throughout surgery in multivariable models. CONCLUSIONS: Low circulating antithrombin activity is associated with lower heparin efficacy, which ultimately leads to a lower ability to suppress thrombin generation during CPB. Determination of risk factors for heparin resistance, and potentially, antithrombin replacement therapy, may individualize and improve anticoagulation treatment.

Antithrombin activity and heparin response in neonates and infants undergoing congenital cardiac surgery: a retrospective cohort study.

PURPOSE: The immature coagulation system during infancy has age-related physiological differences in proteins that contribute to significant variation in heparin responsiveness through alterations in heparin-enhanced thrombin inhibition. The primary aim of this study was to evaluate the relationship between preoperative antithrombin (AT) activity and heparin responsiveness in neonates and infants undergoing congenital cardiac surgery. METHODS: In this retrospective cohort study, neonates (aged 0-28 days) and infants (aged 29-365 days) undergoing congenital cardiac surgery in the 12-month period from October 2013 to 2014 were studied. The two age groups were compared for the primary endpoint of heparin response measured by the heparin sensitivity index (HSI), with heparin loading doses and heparin resistance being secondary endpoints. Multivariable linear regression analyses were used to explore the relationship between AT activity and heparin response measured by HSI. RESULTS: There were 122 infants and 19 neonates included in the study. After adjusting for low-molecular-weight heparin, unfractionated heparin, and platelet count, there was a significant relationship between AT activity and HSI (r = 0.44; P = 0.009). The median [interquartile range] HSI did not differ between neonates and infants (0.76 [0.69- 0.98] vs 0.89 [0.70-1.10] sec·unit(-1)·kg(-1), respectively; median difference, 0.08; 95% confidence interval [CI], -0.01 to 0.17; P = 0.182), despite the mean (standard deviation) AT activity differing between age groups [60 (16)% vs 84 (18)%, respectively; mean difference, 24; 95% CI, 15 to 32; P < 0.001]. CONCLUSIONS: There was a moderate relationship between AT activity and heparin response measured by HSI. Comparing neonates and infants, there was similar heparin responsiveness measured by HSI despite differing AT activity levels. These findings should help guide the perioperative administration of exogenous AT to neonates and infants and suggest that, outside the neonatal period, preoperative AT activity may be used to identify children at risk of decreased heparin responsiveness.

Remote ischemic preconditioning in children undergoing cardiac surgery with cardiopulmonary bypass: a single-center double-blinded randomized trial.

BACKGROUND: Remote ischemic preconditioning (RIPC) harnesses an innate defensive mechanism that protects against inflammatory activation and ischemia-reperfusion injury, known sequelae of cardiac surgery with cardiopulmonary bypass. We sought to determine the impact of RIPC on clinical outcomes and physiological markers related to ischemia-reperfusion injury and inflammatory activation after cardiac surgery in children. METHODS AND RESULTS: Overall, 299 children (aged neonate to 17 years) were randomized to receive an RIPC stimulus (inflation of a blood pressure cuff on the left thigh to 15 mm Hg above systolic for four 5-minute intervals) versus a blinded sham stimulus during induction with a standardized anesthesia protocol. Primary outcome was duration of postoperative hospital stay, with serial clinical and laboratory measurements for the first 48 postoperative hours and clinical follow-up to discharge. There were no significant baseline differences between RIPC (n=148) and sham (n=151). There were no in-hospital deaths. No significant difference in length of postoperative hospital stay was noted (sham 5.4 versus RIPC 5.6 days; difference +0.2; adjusted P=0.91), with the 95% confidence interval (-0.7 to +0.9) excluding a prespecified minimal clinically significant differences of 1 or 1.5 days. There were few significant differences in other clinical outcomes or values at time points or trends in physiological markers. Benefit was not observed in specific subgroups when explored through interactions with categories of age, sex, surgery type, Aristotle score, or first versus second half of recruitment. Adverse events were similar (sham 5%, RIPC 6%; P=0.68). CONCLUSIONS: RIPC is not associated with important improvements in clinical outcomes and physiological markers after cardiac surgery in children. CLINICAL TRIAL REGISTRATION URL: clinicaltrials.gov. Unique identifier: NCT00650507.

Efficacy of Evolving Early-Extubation Strategy on Early Postoperative Functional Recovery in Pediatric Open-Heart Surgery: A Matched Case-Control Study.

There has been a paradigm shift toward "fast-track" management with early extubation (EE) in cardiac surgery. Our retrospective, matched case-control study wishes to define the benefits of EE in pediatric congenital heart surgery. We examined 50 consecutive pediatric cardiac surgery patients extubated in the operating room (February 2009 to July 2009) against a control group of delayed-extubation patients. No significant differences were found in preoperative variables except heart failure medication. Significant intraoperative variables included the following: blood products (363 vs 487 mL, P = .023), morphine (62% vs 6%, P < .0001), and inotropes (16% vs 60%, P < .0001) given. Postoperatively significant differences included hospital stay and lower inotrope scores in the early-extubation group (14.89 vs 31.68, P < .0001). The reintubation rate was not significant. EE patients have equivalent hemodynamic profiles shown by a decreased necessity for inotropic support. We conclude that EE is feasible in low-/medium-risk pediatric congenital heart surgery patients.

Anesthetic considerations for neonates undergoing modified Blalock-Taussig shunt and variations.

The first Blalock-Taussig (BT) shunt was reported in 1944, and during the last 70 years, the procedure has evolved with the development of new materials and devices, and surgical approaches. It has, however, remained central to the palliation of neonates with complex congenital heart disease. The indications have expanded from the original aim of alleviating cyanosis and the pathophysiological results of chronic hypoxemia. They now include lesions with single ventricles, and rehabilitation of small pulmonary arteries. The physiology and hemodynamics of BT shunt circulations are very complex, and adverse hemodynamic events can be difficult to recognize. The consequences of shunt failure can be fatal, and the mortality (3-15%) and morbidity remain distressingly high even in the current era. Neonates undergoing BT shunt procedures or undergoing noncardiac surgery with this anatomy are challenging for the anesthesiologists to manage. There is a significant incidence of periprocedural cardiac arrest, often related to myocardial ischemia. A clear understanding of the anatomy and physiology is important. Any discussion of BT shunt in the current era has to include consideration of hypoplastic left heart syndrome and 'single ventricle' physiology.

The effect of intraoperative hypotension on the outcomes of initial hybrid palliation for single ventricle congenital heart disease: an historical cohort study.

BACKGROUND: The "hybrid procedure" is an alternative surgical palliation strategy for single ventricle congenital heart disease. The purported benefit is improved cognitive ability secondary to avoidance of cardiopulmonary bypass in the neonatal period when neuronal apoptosis is greater. It is unknown whether survival is improved after this procedure. Intraoperative hypotension is common in these patients, and we hypothesized that this hypotension was associated with mortality or morbidity. METHODS: We reviewed the records of 58/58 patients undergoing a first-stage hybrid procedure from 2004 to 2010 in a tertiary pediatric academic centre. Risk factors for poor outcome and the association between intraoperative hypotension and morbidity or mortality were investigated. RESULTS: Average preoperative arterial blood pressure (ABP) [systolic/diastolic presented as mean (standard deviation)] were 68 (12.7) / 38 (9.4) mmHg. Post-induction ABP was 65 (15.2) / 37 (8.6) mmHg. The average intraoperative nadir of ABP was 45 (7.0) / 26 (4.8) mmHg. On return to the intensive care unit (ICU), the average ABP was 69 (13.7) / 38 (11.6) mmHg. The nadir lasted longer than ten minutes in 32/58 patients. The mortality at 48 hr, 60 days, and 12 months was 3/58 (5%), 10/58 (17%), and 15/58 (26%), respectively. Six patients returned to the ICU on extracorporeal membrane oxygenation (ECMO). There was a weak statistical correlation between the average mean and diastolic BP pre-induction and changes of > 20% in systolic and diastolic BP during the case. CONCLUSION: In this patient cohort, we can show an association between short periods of intraoperative hypotension and mortality or return to the ICU on ECMO, but the importance of this is not certain.

New technologies in pediatric anesthesia.

This article reviews potential pediatric applications of 3 new technologies. (1) Pulse oximetry-based hemoglobin determination: Hemoglobin determination using spectrophotometric methods recently has been introduced in adults with varied success. This non-invasive and continuous technology may avoid venipuncture and unnecessary transfusion in children undergoing surgery with major blood loss, premature infants undergoing unexpected and complicated emergency surgery, and children with chronic illness. (2) Continuous cardiac output monitoring: In adults, advanced hemodynamic monitoring such as continuous cardiac output monitoring has been associated with better surgical outcomes. Although it remains unknown whether similar results are applicable to children, current technology enables the monitoring of cardiac output non-invasively and continuously in pediatric patients. It may be important to integrate the data about cardiac output with other information to facilitate therapeutic interventions. (3) Anesthesia information management systems: Although perioperative electronic anesthesia information management systems are gaining popularity in operating rooms, their potential functions may not be fully appreciated. With advances in information technology, anesthesia information management systems may facilitate bedside clinical decisions, administrative needs, and research in the perioperative setting.

Neurological injury and anesthetic neurotoxicity following neonatal cardiac surgery: does the head rule the heart or the heart rule the head?

The improvements in care of children with heart disease have resulted in a major decrease in mortality and increased attention to adverse events and quality of survival. There is important neurological morbidity in children with congenital heart disease. Some problems such as stroke or seizure may be immediately apparent, but others, such as learning disability and motor delay emerge over time. The etiology is multifactorial and includes genetic, procedural and social causes. Only some factors are modifiable. Over the last decade, evidence has been presented that anesthetic drugs may be a potential cause of CNS morbidity. Neonates and infants may be particularly vulnerable to this. The purpose of this article is to describe the multiple known causes of neurodevelopmental impairment in children with heart disease, including anesthetic agents, and to explore the relationship between congenital heart disease and its treatment in this regard.

Poor accuracy of noninvasive cardiac output monitoring using bioimpedance cardiography [PhysioFlow(R)] compared to magnetic resonance imaging in pediatric patients.

BACKGROUND: Identification of low cardiac output (CO) states in anesthesia is important because preoperative hemodynamic optimization may improve outcome in surgery. Accurate real-time CO measurement would be useful in optimizing "goal-directed" therapy. We sought to evaluate the reliability and accuracy of CO measurement using bioimpedance cardiography (PhysioFlow®, NeuMeDx, Bristol, PA) in pediatric patients with and without cardiac disease undergoing anesthesia for magnetic resonance imaging (MRI). METHODS: All consenting patients undergoing anesthesia for cardiac MRI were enrolled. After equilibration of anesthesia for ≥10 minutes, 6 PhysioFlow electrodes were applied to the patient's chest for continuous real-time monitoring for 10 minutes. Data were stored in 15-second epochs and later averaged offline to obtain CO. Phase contrast MRI measurements of flow volumes in the superior vena cava and ascending and descending aorta were made from a single imaging plane through all 3 vessels at the level of the right pulmonary artery. Both CO measurements were indexed to body surface area. The anesthetic technique was the same for both measurements. Agreement was assessed using Bland-Altman analysis. RESULTS: Thirty-one patients were enrolled and 23 were analyzed. The median age at study was 2.8 years (range, 0.02-8.02 years) and median body surface area was 0.54 m(2) (range, 0.21-1.00 m(2)). Eleven of the 23 patients (48%) were males. Patients were grouped into those with univentricular physiology, 6 of 23 (26%); biventricular physiology with shunt, 3 of 23 (13%); biventricular without shunt, 10 of 23 (43%); and no structural heart disease, 4 of 23 (17%). The mean bias was -0.34 ± 1.50 L/min/m(2) (P = 0.29). The 95% limits of agreement were -3.21 to +2.69 L/min/m(2). Only 8 of 23 measurements (35%) were within 20% and 14 of 23 measurements (61%) were within 30% of each other. CONCLUSION: PhysioFlow performance was not sufficiently accurate in this population. Modifications of the algorithm and further testing are required before this device can be recommended for routine clinical use in pediatric patients.

Heparin brand is associated with postsurgical outcomes in children undergoing cardiac surgery.

BACKGROUND: We sought to determine whether the use of specific unfractionated heparin brands during cardiopulmonary bypass for pediatric cardiac surgery was associated with differences in postoperative outcomes, especially regarding the incidence of bleeding and thromboembolic complications. METHODS: We compared postoperative outcomes for pediatric cardiac surgeries performed with Hepalean (Organon Teknika) to those performed with PPC heparin (Pharmaceutical Partners of Canada). Differences in clinical outcomes were determined in multivariable logistic and linear regression models adjusted for patients and surgery characteristics. RESULTS: In all, 903 operations were reviewed, 289 (32%) using Hepalean and 614 (68%) using PPC heparin. Patient demographics and surgical variables were comparable between groups. In multivariable regression models, adjusted for patients' characteristics, heparin use and choice of antifibrinolytic agents, the use of PPC heparin was associated with greater use of red blood cell transfusions in the first 48 postoperative hours (estimates +1.6 mL/kg, p<0.001), increased odds of bleeding complications (odds ratio 3.8, p=0.04), thromboembolic complications (odds ratio 4.7, p=0.01), early unplanned reoperation (odds ratio 6.9, p=0.03), longer postoperative intensive care unit stay (estimate +3.2 days, p<0.001), and longer hospital stay (estimate +3.6 days, p<0.001). CONCLUSIONS: Brand of unfractionated heparin used during cardiopulmonary bypass for pediatric cardiac surgery was associated with bleeding complications and clinical outcomes. Different brands of unfractionated heparin should not be considered equivalent without proper validation in formal trials.

Longer blood storage is associated with suboptimal outcomes in high-risk pediatric cardiac surgery.

BACKGROUND: The negative effects of long-term storage of allogeneic red blood cells (RBCs) on outcomes in adult cardiac surgery have been established, but evidence of a similar effect in pediatric cardiac surgery is limited. METHODS: The weighted average duration of storage for RBC units used in 1,225 pediatric cardiac operations was determined. Operations were divided into high RBC use (more than 4 units or more than 150 mL/kg) or low RBC use. For both categories, associations between storage duration and surgical outcomes, adjusted for relevant patient characteristics, were evaluated. RESULTS: High RBC use was associated with higher surgical complexity. Storage duration for patients who received low RBC volumes was not associated with surgical outcomes. For patients with high RBC transfusion volumes, longer storage duration (per day) was associated with higher odds of bleeding complications (odds ratio 1.029, p=0.07), renal insufficiency (odds ratio 1.085, p=0.001), higher inotrope score after surgery (12 to 24 hours +0.08, p=0.002; 24 to 48 hours +0.07, p<0.001), greater chest tube drainage (24 hours +1.5 mL/kg, p<0.001), longer postoperative hospitalization (+0.3 days p=0.02), and increased in-hospital mortality (odds ratio 1.054, p=0.03). Effects of RBC transfusions on postoperative bleeding were greatest for storage duration longer than 14 days. CONCLUSIONS: The freshest RBC units available should be used for pediatric cardiac operations expected to require more than 4 units or more than 150 mL/kg of allogeneic RBC transfusions, with no units more than 14 days old being transfused whenever possible.

Risk, clinical features, and outcomes of thrombosis associated with pediatric cardiac surgery.

BACKGROUND: Thrombosis, usually considered a serious but rare complication of pediatric cardiac surgery, has not been a major clinical and/or research focus in the past. METHODS AND RESULTS: We noted 444 thrombi (66% occlusive, 60% symptomatic) in 171 of 1542 surgeries (11%). Factors associated with increased odds of thrombosis were age <31 days (odds ratio [OR], 2.0; P=0.002), baseline oxygen saturation <85% (OR, 2.0; P=0.001), previous thrombosis (OR, 2.6; P=0.001), heart transplantation (OR, 4.1; P<0.001), use of deep hypothermic circulatory arrest (OR, 1.9 P=0.01), longer cumulative time with central lines (OR, 1.2 per 5-day equivalent; P<0.001), and postoperative use of extracorporeal support (OR, 5.2; P<0.001). Serious complications of thrombosis occurred with 64 of 444 thrombi (14%) in 47 of 171 patients (28%), and were associated with thrombus location (intrathoracic, 45%; extrathoracic arterial, 19%; extrathoracic venous, 8%; P<0.001), symptomatic thrombi (OR, 8.0; P=0.02), and partially/fully occluding thrombi (OR, 14.3; P=0.001); indwelling access line in vessel (versus no access line) was associated with lower risk of serious complications (OR, 0.4; P=0.05). Thrombosis was associated with longer intensive care unit (+10.0 days; P<0.001) and hospital stay (+15.2 days; P<0.001); higher odds of cardiac arrest (OR, 4.9; P<0.001), catheter reintervention (OR, 3.3; P=0.002), and reoperation (OR, 2.5; P=0.003); and increased mortality (OR, 5.1; P<0.001). Long-term outcome assessment was possible for 316 thrombi in 129 patients. Of those, 197 (62%) had resolved at the last follow-up. Factors associated with increased odds of thrombus resolution were location (intrathoracic, 75%; extrathoracic arterial, 89%; extrathoracic venous, 60%; P<0.001), nonocclusive thrombi (OR, 2.2; P=0.01), older age at surgery (OR, 1.2 per year; P=0.04), higher white blood cell count (OR, 1.1/10(9) cells per 1 mL; P=0.002), and lower fibrinogen (OR, 1.4/g/L; P=0.02) after surgery. CONCLUSIONS: Thrombosis affects a high proportion of children undergoing cardiac surgery and is associated with suboptimal outcomes. Increased awareness and effective prevention and detection strategies are needed.

Cardiac arrest upon induction of anesthesia in children with cardiomyopathy: an analysis of incidence and risk factors.

INTRODUCTION: It is thought that patients with cardiomyopathy have an increased risk of cardiac arrest on induction of anesthesia, but there is little available data. The purpose of this study was to identify the incidence and potential risk factors for cardiac arrest upon induction of anesthesia in children with cardiomyopathy in our institution. METHODS: A retrospective chart review was performed. Eligible patients included patients admitted between 1998 and 2008 with the International Statistical Classification of Disease code for cardiomyopathy (ICD-9 code 425) who underwent airway intervention for sedation or general anesthesia in the operating room, cardiac diagnostic and interventional unit (CDIU) or intensive care unit. Patients undergoing emergency airway intervention following cardiovascular collapse were excluded. For each patient, we recorded patient demographics, disease severity, anesthesia location, and anesthetic technique. RESULTS: One hundred and twenty-nine patients with cardiomyopathy underwent a total of 236 anesthetic events, and four cardiac arrests were identified. One was related to bradycardia (HR<60), two were attributed to bradycardia in association with severe hypotension (systolic blood pressure<45), and the fourth arrest was related to isolated severe hypotension. Two occurred in the operating suite and two in the CDIU. There was no resulting mortality. One patient progressed to heart transplantation. Multiple combinations of anesthetic drugs were used for induction of anesthesia. CONCLUSION: We performed a review of the last 10 years of anesthesia events in children with cardiomyopathy. We report four cardiac arrests in two patients and 236 anesthetic events (1.7%). To the best of our knowledge, this is the largest review of these patients to date but is limited by its retrospective nature. The low cardiac arrest incidence prevents the identification of risk factors and the development of a cardiac arrest risk predictive clinical tool.

A comparison of cardiac output by thoracic impedance and direct fick in children with congenital heart disease undergoing diagnostic cardiac catheterization.

OBJECTIVE(S): To evaluate the measurement of cardiac output (CO) using continuous electrical bioimpedance cardiography (Physioflow; Neumedx, Philadelphia, PA) (CO(PF)) with a simultaneous direct Fick measurement (CO(FICK)) in children with congenital heart disease. DESIGN: A prospective cohort study comparing 2 methods of measurement of CO. SETTING: A quaternary university-affiliated pediatric hospital. PARTICIPANTS: Children undergoing cardiac catheterization for clinical care. INTERVENTIONS: The Physioflow measured continuous real time CO in 15-second epochs and simultaneous measurement of cardiac output by direct Fick (with mass spectrometry to assess VO(2)) were acquired. MEASUREMENTS AND MAIN RESULTS: Sixty-five patients were recruited, and data from 56 (25 males) were adequate for analysis. The median age at study was 3.5 years (range, 0.4-16.6 years), and the median body surface area was 0.62 m(2) (range, 0.31-1.71). There were 25 of 56 (45%) with univentricular physiology. A total of 19,228 Physioflow data points were available for the analysis of which 14,569 (76%) were valid; 96% of the invalid measurements were identified as artifacts by the device. The average cardiac index of valid measurements was 3.09 ± 0.72 L/min/m(2). Compared with the Fick CO, the mean bias was -0.09 L/min, but the 95% limits of agreement were -3.20 to +3.01 L/min/m(2). Consequently, only 20 of 56 (36%) of measurements were within 20%, and 31 of 56 (55%) of measurements were within 30% of each other. CONCLUSIONS: Compared with measurements made by direct Fick, CO measured using the Physioflow device was unreliable in anesthetized children with congenital heart disease.

Acute effects of the ACE inhibitor enalaprilat on the pulmonary, cerebral and systemic blood flow and resistance after the bidirectional cavopulmonary connection.

BACKGROUND: The bidirectional cavopulmonary connection (BCPC) is used in the staged palliation of univentricular hearts and places the cerebral and pulmonary vascular beds in series. Angiotensin-converting enzyme inhibitors (ACEI) are often used in this complex circulation, but the effects of their vasodilation are unclear. OBJECTIVE: Assessment of the acute response of perfusion pressure, flow and resistance across the systemic, cerebral and pulmonary vascular beds to ACEI in patients with a BCPC. DESIGN: Prospective interventional study. SETTING: Single tertiary care centre. PATIENTS: 12 patients with a BCPC (median age 28 months, weight 11.8 kg) undergoing a pre-Fontan catheterisation with MRI measurement of flows. INTERVENTION: Intravenous enalaprilat 0.005 or 0.01 mg/kg. RESULTS: Enalaprilat increased descending aorta flow (median 21.6%, p=0.0005), decreased total pulmonary vein flow (median 10.6%, p=0.025), and both superior caval vein flow (median 8.6%, p=0.065) and aortopulmonary collateral flow (median 15.5%, p=0.077) tended to decrease. Total cardiac output was unchanged (p=0.57). Systemic vascular resistance (median 41.9%, p=0.0005) and cerebral vascular resistance (median 23.4%, p=0.0005) decreased, but pulmonary vascular resistance (p=0.73) showed little change. There was evidence of autoregulation of cerebral blood flow. The proportion of descending aortic flow to total cardiac output increased (median 27 to 35%, p=0.001). Systemic oxygen saturation decreased from 87% to 83% (p=0.02). CONCLUSION: Enalaprilat did not increase total cardiac output but redistributed flow to the lower body, with a concomitant decrease in arterial oxygen saturation. It is difficult to increase cardiac output in patients with a BCPC and ACEI should be used with caution in those with borderline aortic saturations.

Improved outcomes associated with intraoperative steroid use in high-risk pediatric cardiac surgery.

BACKGROUND: Corticosteroids are commonly administered perioperatively in pediatric cardiac surgery to reduce cardiopulmonary bypass induced inflammation. However, their effects on outcomes and potential for adverse events are not well defined. METHODS: A review was undertaken of cardiac operations between September 2004 and December 2007 carrying a comprehensive Aristotle score 10 or greater. A nonrandomized comparison was undertaken comparing those patients having received intraoperative methylprednisolone at anesthesia induction or in the bypass circuit prime with those who did not. To account for nonrandom assignment of steroid use, a propensity model was created to establish each patient's probability of having received steroids (∼150 variables evaluated, 17 in final model, c-stat 0.94, p < 0.001). Associations between postoperative outcomes and intraoperative steroid use were modeled in multivariable linear regression models adjusted for propensity score and relevant surgical characteristics. RESULTS: In 221 identified cases, 134 (61%) patients received intraoperative steroids; of these, 44 (33%) also received preoperative doses. In propensity-adjusted regression models, intraoperative steroid use was associated with lower chest tube volume loss in the first 24 postoperative hours (-5.3 mL/kg, p < 0.001), and shorter durations of stay in intensive care (-2.3 days, p < 0.001) and hospital (-4.1 days, p < 0.001). Use of an additional preoperative dose resulted in further improvements, especially a reduction in duration of mechanical ventilation (-1.7 days versus no steroids, -1.2 days versus intraoperative steroids only, p = 0.002). Steroids were not associated with increased postoperative lactate, creatinine, or glucose levels, or odds of infection. CONCLUSIONS: Intraoperative steroid use is associated with improved postoperative outcomes for children undergoing high-risk cardiac surgery, with further benefits associated with a preoperative dose.

Pediatric cardiac anesthesia in the developing world.

More children die of congenital heart disease (CHD) in low-income countries and acquired cardiac disease is more frequent. Advances in diagnosis, surgery, perfusion and anesthesia in the developed world have had dramatic results on children's lives, and many forms of CHD can now be safely corrected or palliated. However, in developing countries, for the children who receive cardiac surgery, perioperative mortality and morbidity remain high. Pediatric cardiac anesthesia is a specialty in its infancy worldwide, and in developing countries, it is often nonexistent. Visiting 'specialists' as part of medical mission teams often provides anesthesia, but the hope for the future is that local staff will be trained in pediatric cardiac anesthesia and collaborative regional cardiac centers will be the mainstay of care, offering safer surgery to more children.