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Jacqueline Viegas,1 Helen Holtby,2 Kyle Runeckles,3 Elvira V Lang4 1Cardiac Diagnostic and Interventional Unit, Labatt Family Heart Centre, The Hospital for Sick Children, Toronto, Ontario, Canada; 2Department of Anesthesia, The Hospital for Sick Children, Toronto, Ontario, Canada; 3University Health Network Research Institute, Toronto, Ontario, Canada; 4Hypnalgesics, LLC, Brookline, MA, USACorrespondence: Jacqueline Viegas, Cardiac Diagnostic and Interventional Unit, Labatt Family Heart Centre, The Hospital for Sick Children, 555 University Ave, Toronto, Ontario, M5G1X8, Canada, Tel +1 416 659 4443, Fax +1 416 813 6404, Email jacqueline.viegas@sickkids.caPurpose: 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.Clinicaltrials.gov Identifier: NCT02347748.Keywords: sedation, anesthesia, children, pain, anxiety

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. 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. 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]. 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.

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.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.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, p0.001), greater chest tube drainage (24 hours +1.5 mL/kg, p0.001), 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.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.

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.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.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, p0.001), 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, p0.001), and longer hospital stay (estimate +3.6 days, p0.001).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.

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 P =0.002), baseline oxygen saturation P =0.001), previous thrombosis (OR, 2.6; P =0.001), heart transplantation (OR, 4.1; P P =0.01), longer cumulative time with central lines (OR, 1.2 per 5-day equivalent; P P P 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 P P P =0.002), and reoperation (OR, 2.5; P =0.003); and increased mortality (OR, 5.1; P P 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.

ObjectivesThe purpose of our study was to characterize the hemodynamic and corresponding pharmacokinetic responses to a single dose of oral sildenafil by children with pulmonary arterial hypertension (PAH) undergoing invasive testing.BackgroundAlthough used frequently for the treatment of children with PAH, data regarding the acute responses to sildenafil are limited.MethodsThirty-six patients (mean age 7.5 ± 5.9 years; 24 females) were studied during cardiac catheterization with general anesthesia. Eight of 36 (22%) had idiopathic PAH; the remainder had associated congenital heart disease. Hemodynamics and serum cyclic-guanosine monophosphate levels (cGMP) were evaluated at baseline and after inhaled nitric oxide (NO) (40 ppm). In addition, cGMP and sildenafil levels were measured 30 min after administration of sildenafil (0.5 mg/kg, suspended in 5 ml sterile water) through a nasogastric tube.ResultsFor the 36 patients, the pulmonary vasodilating capability of oral sildenafil was lower than that of inhaled NO (2.8% vs. 11.6% reduction in pulmonary vascular resistance indexed to body surface area [PVRI], respectively; p = 0.01). However, only 21 of 36 (58%) patients had a detectable sildenafil level. In those with detectable sildenafil levels, the fall in PVRI was greater (−11.6% vs. −19.1%, p = NS). Mean cGMP levels at baseline and after NO were 41.8 ± 20.0 pmol/ml and 83.8 ± 35.5 pmol/ml, respectively (p < 0.0001). Surprisingly, there was no significant increase in cGMP in patients with either undetectable (37.5 ± 29.8 pmol/ml) or detectable (44.4 ± 31.7 pmol/ml) sildenafil levels (p = NS compared with baseline) with sildenafil.ConclusionsOur study demonstrates suboptimal absorption of sildenafil in almost half the children undergoing acute hemodynamic testing. When detectable, there was no statistically significant difference between the fall in PVRI associated with sildenafil and NO despite lower circulating cGMP levels in the sildenafil group. These data should be taken into account when designing acute testing protocols, and assessing the acute response to sildenafil in patients with PAH.

We present a 15-yr-old-girl who underwent interventional lung assist via Novalung (Novalung GmbH, Lotzenaecker, Heckingen, Germany) insertion as a bridge to bilateral lung transplantation for pulmonary veno-occlusive disease. This is the first pediatric and smallest patient to receive the device. Central cannulation was chosen to optimize blood flow through the device by enabling larger-sized cannulae in a patient with high pulmonary artery pressure. Novalung provided circulatory support with oxygenation obviating the need for extracorporeal membrane oxygenation while waiting for lung transplantation.

Hybrid strategies for single ventricle palliation may differ from Norwood strategies in terms of anatomic and physiologic growth stimuli to the pulmonary arteries (PA), hemodynamics, resource utilization, and survival. Few studies have directly compared these strategies.In all, 58 patients underwent Norwood (Blalock-Taussig shunt; n = 39) or hybrid (n = 19) single ventricle palliation (2004 to 2007). Hemodynamics, PA morphology, hemodynamics, resource utilization, and survival were reviewed.At pre-stage 2 evaluation, there were nonsignificant trends toward lower ventricular end-diastolic pressure, higher mixed venous saturation, and larger Nakata and lower lobe indices in the hybrids. Mean PA pressures were not different between groups. Four Norwood patients (10%) underwent transplantation before stage 2 palliation. Forty-two patients underwent stage 2 palliation (bidirectional cavopulmonary shunt or stage 2 hybrid (aortic arch reconstruction and bidirectional cavopulmonary shunt). Requirement for PA plasty, postoperative CVP, stage 2 survival, and 1-year survival were similar between groups. Combined (stage 1 plus stage 2) intubation time, intensive care unit time, and hospital length of stay was shorter for hybrids in comparison with Norwood survivors (p0.05). Comparison of resource utilization at the time of arch reconstruction (Norwood procedure or stage 2 hybrid), demonstrated a time-related trend toward improvement (weak negative correlation: intubation, rho = -0.386, p = 0.172; intensive care unit stay, rho = -0.487, p = 0.077; hospital stay, rho = -0.429, p = 0.126) in the hybrid group, but not in the Norwood group.Hybrid palliation does not have a significant adverse impact on PA development, with comparable PA growth and hemodynamics. The demonstration of equivalent survival, diminished hospital utilization, and trends indicating ongoing refinement of the hybrid strategy warrants a prospective randomized trial.

Objective This study compared the effects of reconstituted fresh whole blood against standard blood component therapy in neonates undergoing cardiac surgery. Methods Patients less than 1 month of age were randomized to receive either reconstituted fresh whole blood (n = 31) or standard blood component therapy (n = 33) to prime the bypass circuit and for transfusion during the 24 hours after cardiopulmonary bypass. Primary outcome was chest tube drainage; secondary outcomes included transfusion needs, inotrope score, ventilation time, and hospital length of stay. Results Patients who received reconstituted fresh whole blood had significantly less postoperative chest tube volume loss per kilogram of body weight (7.7 mL/kg vs 11.8 mL/kg; P = .03). Standard blood component therapy was associated with higher inotropic score (6.6 vs 3.3; P = .002), longer ventilation times (164 hours vs 119 hours; P = .04), as well as longer hospital stays (18 days vs 12 days; P = .006) than patients receiving reconstituted fresh whole blood. Of the different factors associated with the use of reconstituted fresh whole blood, lower platelet counts at 10 minutes and at the end of cardiopulmonary bypass, older age of cells used in the prime and throughout bypass, and exposures to higher number of allogeneic donors were found to be independent predictors of poor clinical outcomes. Conclusions Reconstituted fresh whole blood used for the prime, throughout cardiopulmonary bypass, and for all transfusion requirements within the first 24 hours postoperatively results in reduced chest tube volume loss and improved clinical outcomes in neonatal patients undergoing cardiac surgery.

ObjectiveCarbon dioxide is suggested to increase oxygen delivery after the Norwood procedure. We sought to quantitatively define the effects of stepwise increases in arterial carbon dioxide tension on systemic oxygen transport and cerebral and splanchnic circulation after the Norwood procedure.MethodsSeven sedated, paralyzed, and mechanically ventilated neonates were studied after the Norwood procedure. Arterial carbon dioxide tension increased from 40-50-60 mm Hg using inspired carbon dioxide. Each step was 30 minutes. Pulmonary and systemic blood flow, vascular resistance, and oxygen delivery were calculated with the measurement of oxygen consumption and blood gases and pressures from the aorta, superior vena cava, and pulmonary vein. Plasma epinephrine and norepinephrine were measured. Cerebral and splanchnic oxygen saturations were measured by near-infrared spectroscopy, and cerebral blood flow velocity was measured by transcranial Doppler.ResultsStepwise increase in arterial carbon dioxide tension was associated with a decrease in systemic vascular resistance (P < .001) and an increase in systemic blood flow (P < .01) and oxygen delivery (P < .0001), but not with significant changes in total pulmonary vascular resistance and pulmonary blood flow. Cerebral oxygen saturation increased (P < .0001), and splanchnic oxygen saturation decreased (P < .01). Oxygen consumption decreased (P < .01), and epinephrine and norepinephrine increased (P < .01 and .05).ConclusionModerate hypercapnia increases systemic blood flow because of its effect on systemic vascular resistance after the Norwood procedure. The increase in systemic blood flow is primarily a consequence of increased cerebral blood flow that compromises splanchnic circulation. The decrease in oxygen consumption improves oxygen transport, but the increase in catecholamines may be undesirable. Clinical use of carbon dioxide aiming to improve oxygen delivery should be with caution.

Background The comprehensive Aristotle score has been proposed as an individualized measure of the complexity of a given surgical procedure and has been reported to significantly correlate with postoperative morbidity and mortality after the Norwood procedure. An important factor leading to postoperative morbidity and mortality is low cardiac output. We studied the correlation between the comprehensive Aristotle score and cardiac output (CO) in infants after the Norwood procedure. Methods and Results Respiratory mass spectrometry was used to continuously measure systemic oxygen consumption (VO 2 ) in 22 infants for 72 hours postoperatively. Arterial, superior vena caval and pulmonary venous blood gases were measured at 2 to 4 hour intervals to calculate CO. The comprehensive Aristotle score was collected. Hospital mortality was 4.5%. The comprehensive Aristotle score ranged from 14.5 to 23.5 and negatively correlated with CO ( P = 0.027). Among the patient-adjusted factors, myocardial dysfunction (n = 10), mechanical ventilation to treat cardiorespiratory failure (n = 9) and atrioventricular valve regurgitation (n = 4) ( P = 0.01) negatively correlated with CO ( P = 0.06 to 0.07). Aortic atresia (n = 9) was associated with a lower CO ( P = 0.01) for the first 24 hours which linearly increased overtime ( P = 0.0001). No correlation was found between CO and other factors ( P > 0.3 for all). Conclusions Comprehensive Aristotle score significantly negatively correlates with CO after the Norwood procedure. A preoperative estimation of the comprehensive Aristotle score, particularly in association with myocardial dysfunction, mechanical ventilation to treat cardiorespiratory failure, atrioventricular valve regurgitation and aortic atresia may help to anticipate a high postoperative morbidity with low cardiac output syndrome.

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 aged1 year. We sought to determine the impact of baseline antithrombin activity on response to heparin and thrombin generation during cardiopulmonary bypass (CPB).Secondary analysis was performed using linear regression analyses, which combined patients from a trial of individualized versus weight-based heparin management for 90 infants aged1 year undergoing cardiac surgery.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.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.

ObjectivesThe purpose of this study was to evaluate the effects of dopamine on hemodynamic status and oxygen transport in neonates after the Norwood procedure.BackgroundDopamine is widely used to augment cardiac performance and increase oxygen delivery (Do2) in patients after cardiopulmonary bypass (CPB). This might be at the expense of increased myocardial and systemic oxygen consumption (Vo2), thus offsetting the improved Do2. This balance is particularly fragile in critically ill neonates.MethodsSystemic oxygen consumption was continuously measured with respiratory mass spectrometry in 13 sedated, paralyzed, and mechanically ventilated neonates for 72 h after the Norwood procedure. Arterial, superior vena caval, and pulmonary venous blood gases were measured to calculate pulmonary blood flow (Qp) and systemic blood flow (Qs), Do2, and oxygen extraction ratio (ERo2). Rate-pressure product was calculated. Dopamine at a dose of 5 μg/kg/min was routinely administered at cessation of CPB and terminated within the first 48 h. Hemodynamic and oxygen transport measures were obtained before and at 100 min after the termination of dopamine.ResultsTerminating dopamine was not associated with significant changes in arterial pressure, Qp, Qs, or Do2but was associated with a significant decrease in heart rate (p = 0.003), rate-pressure product (p = 0.03), and Vo2(−20 ± 11%, p < 0.0001), resulting in a significant decrease in ERo2(p = 0.01).ConclusionsDopamine induces a significant increase in Vo2in neonates after the Norwood procedure, and termination is associated with an improved balance of Vo2–Do2. These data further emphasize the importance of understanding changes in Vo2as well as Do2in infants after cardiac surgery.

OBJECTIVES: We conducted a randomized controlled trial of the effects of remote ischemic preconditioning (RIPC) in children undergoing repair of congenital heart defects. BACKGROUND: Remote ischemic preconditioning reduces injury caused by ischemia-reperfusion in distant organs. Cardiopulmonary bypass (CPB) is associated with multi-system injury. We hypothesized that RIPC would modulate injury induced by CPB. METHODS: Children undergoing repair of congenital heart defects were randomized to RIPC or control treatment. Remote ischemic preconditioning was induced by four 5-min cycles of lower limb ischemia and reperfusion using a blood pressure cuff. Measurements of lung mechanics, cytokines, and troponin I were made pre- and postoperatively. RESULTS: Thirty-seven patients were studied. There were 20 control patients and 17 patients in the RIPC group. The mean age and weight of the RIPC and control patients were not different (0.9 +/- 0.9 years vs. 2.2 +/- 3.4 years, p = 0.4; and 6.9 +/- 2.9 kg vs. 11.5 +/- 10 kg, p = 0.06). Bypass and cross-clamp times were not different (80 +/- 24 min vs. 88 +/- 25 min, p = 0.3; and 55 +/- 13 min vs. 59 +/- 13 min, p = 0.4). Levels of troponin I postoperatively were greater in the control patients compared with the RIPC group (p = 0.04), indicating greater myocardial injury in control patients. Postoperative inotropic requirement was greater in the control patients compared with RIPC patients at both 3 and 6 h (7.9 +/- 4.7 vs. 10.9 +/- 3.2, p = 0.04; and 7.3 +/- 4.9 vs. 10.8 +/- 3.9, p = 0.03, respectively). The RIPC group had significantly lower airway resistance at 6 h postoperatively (p = 0.009). CONCLUSIONS: This study demonstrates the myocardial protective effects of RIPC using a simple noninvasive technique of four 5-min cycles of lower limb ischemia and reperfusion. These novel data support the need for a larger study of RIPC in patients undergoing cardiac surgery.

ObjectiveManagement strategy for the postoperative Norwood neonate has been formulated from models that have estimated oxygen consumption (vo2). Superior vena caval oxygen saturation (Svo2), systemic arterial and superior vena caval oxygen saturation difference (Sa-vo2), and oxygen excess factor (Ω = arterial oxygen saturation/Sa-vo2) have been used as indirect indicators to estimate systemic blood flow (Qs) and oxygen delivery (Do2). We sought to examine the correlation of the indirect indicators to vo2-derived measures of oxygen transport.MethodsRespiratory mass spectrometry was used to continuously measure vo2 after the Norwood procedure (n = 13). Measured saturations and the direct Fick equation were used to obtain pulmonary blood flow, Qs, DO2, and oxygen extraction ratio (ERo2) values. Correlations to Svo2, Sa-vo2, and Ω were sought.ResultsThere was a close correlation of Svo2, Sa-vo2, and Ω to ERo2 (r = 0.92, 0.96, and 0.97, respectively; P < .0001). Correlation to Qs and Do2 was variable (r = 0.39 to 0.78, respectively; P < .0001). Correlation to vo2 was poor but significant (r = 0.24 to 0.40, P < .0001). Inclusion of vo2 improved the correlation to Qs and Do2 (r = 0.66 to 0.97, P < .0001).ConclusionsThe close correlation of Svo2, Sa-vo2, and Ω to ERo2 indicates that each is a measure of the balance of Do2 and extraction. The significant but less reliable correlation to Do2 and vo2 indicates the values for Svo2, Sa-vo2, and Ω do not discriminate between the contribution of Do2 and vo2. Measured vo2 and hemodynamics may improve the optimization of postoperative management strategy in the individual neonate.

Background— Pulmonary arterial hypertension (PAH) is a progressive and fatal disease. Sildenafil is a type 5 phosphodiesterase inhibitor and pulmonary vasodilator. Therefore, we hypothesized that sildenafil would improve distance walked in 6 minutes and hemodynamics in children with PAH. Methods and Results— After baseline assessment of hemodynamics by cardiac catheterization and distance walked in 6 minutes, we administered oral sildenafil at 0.25 to 1 mg/kg 4 times daily to 14 children (median age, 9.8 years; range, 5.3 to 18). Diagnoses were primary (n=4) and secondary (n=10) PAH. We repeated the 6-minute walk test at 6 weeks and at 3, 6, and 12 months (n=14) and cardiac catheterization (n=9) after a median follow-up of 10.8 months (range, 6 to 15.3). During sildenafil therapy, the mean distance walked in 6 minutes increased from 278±114 to 443±107 m over 6 months ( P =0.02), and at 12 months, the distance walked was 432±156 m ( P =0.005). A plateau was reached between 6 and 12 months ( P =0.48). Mean pulmonary artery pressure decreased from a median of 60 mm Hg (range, 50 to 105) to 50 mm Hg (range, 38 to 84) mm Hg ( P =0.014). Median pulmonary vascular resistance decreased from 15 Wood units m 2 (range, 9 to 42) to 12 Wood Units m 2 (range, 5 to 29) ( P =0.024). Conclusions— Oral sildenafil has the potential to improve hemodynamics and exercise capacity for up to 12 months in children with PAH. Confirmation of these results in a randomized, controlled trial is essential.

Introduction: Heparin-based anticoagulation in children is challenging as they have a high prevalence of heparin resistance. Antithrombin, one of the main natural anticoagulant inhibitors that potentiate heparin anticoagulation activity, might be a critical component of heparin response and anticoagulation effectiveness. Objectives: Determine the impact of antithrombin levels on anticoagulation (heparin sensitivity and effectiveness) during cardiopulmonary bypass (CPB) in children Methods: Secondary analysis of a randomized controlled trial of individualized vs weight based heparin management in 90 infants Results: As expected, older patients had higher blood antithrombin levels (relative increase of 16±6% for patients >6 months old vs. those Conclusions: Low antithrombin level is associated with resistance to heparin and decreased anticoagulation activity, ultimately leading to lower ability to suppress thrombin generation during CPB. Antithrombin supplementation may potentially individualize and improve anticoagulation.

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: NCT 00650507.

Background It is unclear if children after heart transplantation (HTX) are at risk for developing increased myocardial fibrosis. Diffuse myocardial fibrosis can be estimated by myocardial longitudinal relaxation (T1) times. Methods Twenty cardiovascular magnetic resonance (CMR) studies in 17 patients after HTX (mean age 13.2 years, range 1.2 17.4 years, 9 female) were analysed retrospectively and compared to CMR studies in nine healthy controls

Background Cerebral hyperthermia after hypothermic cardiopulmonary bypass has been poorly documented for adults and never in children. This study was designed to monitor brain temperature during and up to 6 h after cardiopulmonary bypass in infants and children. Methods Fifteen infants and children, between 3 months and 6 yr of age, were studied. A right retrograde jugular bulb catheter was used to measure the jugular venous bulb temperature (JVBT) during the procedure and the first 6 h in the critical care unit. The temperature of the blood from the bypass machine was measured at the aorta through the cannula using an indwelling temperature probe. All data were acquired every minute. Results The age of the patients ranged from 3 to 71 months (median, 15 months). The mean weight was 11.5 +/- 8.4 kg. The mean JVBT recorded at the end of cardiopulmonary bypass was 36.9 +/- 1.4 degrees C but reached 39.6 +/- 0.8 degrees C after six h (P < 0.01). The kinetics of brain rewarming was determined by the slope of the mean JVBT and corresponded to y +/- 0.006x + 37.21 (r2 = 0.97). The JVBT differed from the tympanic temperature after 200 min (P < 0.01) and the lower esophageal (P < 0.05) and rectal (P < 0.001) temperatures after 300 min. After 6 h, the tympanic, rectal, and lower esophageal temperatures were 37.8 +/- 0.9, 37.7 +/- 0.6, and 38.4 +/- 0.7 degrees C, respectively, whereas the JVBT was 39.6 +/- 0.8 degrees C (P < 0.001). However, the correlation coefficients between the JVBT and the tympanic, rectal, and esophageal temperatures were 0.98, 0. 85, and 0.97, respectively. No complications were recorded with placement of the jugular bulb catheter. Conclusions Mean JVBT was significantly increased over the mean core temperature at all times from rewarming by cardiopulmonary bypass onward. Although the lower esophageal, rectal, and tympanic temperatures correlated well with JVBT, all three failed to reflect JVBT during recovery. This observation might help to elucidate factors involved in the functional and structural neurologic injury known to occur in pediatric patients.

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.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, p0.001). Associations between postoperative outcomes and intraoperative steroid use were modeled in multivariable linear regression models adjusted for propensity score and relevant surgical characteristics.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, p0.001), and shorter durations of stay in intensive care (-2.3 days, p0.001) and hospital (-4.1 days, p0.001). 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.Intraoperative steroid use is associated with improved postoperative outcomes for children undergoing high-risk cardiac surgery, with further benefits associated with a preoperative dose.

Objective: Aortic atresia (AA) is a risk factor for mortality after the Norwood procedure. The mechanisms remain unknown. We compared the profiles of systemic, cerebral, and splanchnic oxygen transport in neonates with hypoplastic left-heart syndrome with AA or aortic stenosis (AS) after the Norwood procedure. Methods: Systemic oxygen consumption (VO2) was measured using respiratory mass spectrometry for 72 h in 17 neonates(nineinthe AAgroup,eightintheASgroup).Cardiacoutput(CO),systemicvascularresistance (SVR),oxygendelivery(DO2),and oxygen extraction ratio (ERO2) were calculated combining with blood gases and pressures at 2—4-h intervals. Cerebral (ScO2) and splanchnic (SsO2) oxygen saturations were measured by near-infrared spectroscopy. The doses of dopamine, milrinone, phenoxybenzamine, and vasopressin were recorded. Preoperative echocardiographic left-ventricular morphology and ejection fraction ratio were measured. Results: Compared with the AS group,the AA grouphad lower CO (p = 0.03), higher SVR(p = 0.002), lowerDO2 (p = 0.07), VO2 (p = 0.003), and ScO2 (p = 0.07) duringthe first 40 h. SsO2 was insignificantly lower. Despite a similar ERO2, the AA group had higher lactate (p = 0.01). The AA group received higher doses of milrinone (p < 0.0001), vasopressin (p = 0.005), and phenoxybenzamine (p = 0.02), and lower higher doses of dopamine (p = 0.07). Vasopressin adversely correlated with systemic oxygen-transport variables and SsO2 (p < 0.05). The AA group had thicker left-ventricular posterior wall (p = 0.05) that was negatively correlated with CO (p = 0.02). Conclusions: AA is associated with an inferior status of systemic, cerebral, and splanchnic oxygen transport after the Norwood procedure. Aggressive use of vasopressin may worsen systemic oxygen transport and decrease splanchnic perfusion. # 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Aortic atresia (AA) has been identified as a risk factor for mortality after the Norwood procedure. We compared postoperative systemic and regional (cerebral and splanchnic) oxygen transport profiles in neonates with hypoplastic left heart syndrome with or without AA after the Norwood procedure. Systemic oxygen consumption (VO 2 ) was measured using respiratory mass spectrometry postoperatively for 72 hrs in 17 neonates (n=9 in AA group and 8 in non-AA group). Arterial, superior vena cava, and pulmonary venous blood gases and pressures were measured at 2– 4 hr intervals to calculate cardiac output (CO), systemic vascular resistance (SVR), oxygen delivery (DO 2 ) and oxygen extraction ratio (ERO 2 ). Cerebral (ScO 2 ) and splanchnic (SsO 2 ) oxygen saturations were measured using near infrared spectroscopy. The doses of dopamine, vasopressin (up to 0.0008 unit/kg/min), phenoxybenzamine and milrinone were noted. When compared to non-AA group, AA group had lower CO (p=0.03), higher systolic arterial blood pressure (p=0.01) and SVR (p=0.002), lower DO 2 (p=0.07), VO 2 (p=0.003) and ScO 2 during the first 30 to 40 hrs. There was no significant difference in SsO 2 (p=0.12, n=7 in AA group and 3 in non-AA group). Despite a similar ERO 2 (p=0.5), AA group had higher lactate over 72 hrs (p=0.01). AA group received higher doses of vasopressin (p=0.005) and milrinone (p2 negatively correlated with vasopressin (p=0.05), positively correlated with milrinone (p=0.03) and dopamine (p2 that positively correlated with dopamine, but not with other drugs. Aortic atresia is associated with an inferior status of systemic, cerebral and splanchnic oxygen transport in neonates after the Norwood procedure. Aggressive use of vasopressin worsens systemic and splanchnic oxygen transport status. Postoperative management strategies should be directed to improve both systemic and regional oxygen transport in this special group of patients.

We appreciate the contribution of Dr Schranz and colleagues to the development of the hybrid procedure for single ventricle palliation and their insightful comments regarding our recent article.1 The hybrid procedure with bilateral pulmonary banding and arterial duct stenting was designed as a minimally invasive alternative to a Norwood procedure. By avoiding cardiopulmonary bypass and the consequent ischemia-reperfusion injury and systemic inflammatory response, we hypothesized that we would find minimally altered systemic hemodynamic and oxygen transport status as compared with the well-documented hemodynamic derangements associated with the Norwood procedure.2 We evaluated the hybrid strategy through analysis of dispassionate and objective data and, to our knowledge, our study represents the only published hemodynamic assessment of this strategy. As noted in our article, the patterns of hemodynamic alterations after hybrid procedures were more complex than might have been anticipated. Although the data are precise, Dr Schranz and colleagues appear to be concerned that these data may not accurately represent all hybrid procedures. Our intuition (without data) would suggest that this may be so and, consequently, we will endeavor to obtain another dataset in the future to determine whether the early position of this cohort on our learning curve was an important modulator of …

Background— After the Norwood procedure, early postoperative neonatal physiology is characterized by hemodynamic instability and imbalance of oxygen transport that is commonly attributed to surgical myocardial injury and a systemic inflammatory response to cardiopulmonary bypass (CPB). Because the Hybrid procedure (arterial duct stenting and bilateral pulmonary artery banding) avoids CPB, cardioplegic arrest, and circulatory arrest, we hypothesized that the Hybrid procedure is associated with superior postoperative hemodynamics and oxygen transport. Methods and Results— Oxygen consumption (VO 2 ) was continuously measured using respiratory mass spectrometry for 72 hours after Hybrid (n=6) and Norwood (n=13) procedures. Arterial, superior vena cava, and pulmonary venous blood gases and pressures were measured at 2- to 4-hour intervals to calculate systemic and pulmonary blood flows (Qs, Qp), and systemic vascular resistance (SVR), total pulmonary vascular resistance including pulmonary arterial band or B-T shunt (tPVR), cardiac output (CO), oxygen delivery (DO 2 ), and oxygen extraction ratio (ERO 2 ). Rate-pressure product was calculated as heart rate×systolic arterial pressure. When compared with the Norwood procedure, the early postoperative Hybrid patients had lower CO, higher SVR, and higher Qp:Qs ratios. In addition, the DO 2 and VO 2 were both lower in the Hybrids with higher ERO 2 and lactate levels. This early postoperative pattern reversed after 48 hours. Conclusions— Although Hybrid procedure avoids CPB and cardioplegic arrest, the early hemodynamic profile is not superior to the Norwood in terms of cardiac output and control of pulmonary blood flow. These data strongly suggest that a “hands off” approach to postoperative care in Hybrid patients may not be appropriate in patients with preoperative diminished myocardial function; and in such patients a Norwood-derived management strategy (afterload reduction and inotropic support) should be considered.

We describe a case of "topsy-turvy heart" that necessitated simultaneous left tracheobronchial repair, aortic arch reconstruction, and bronchial stenting in an 11-month-old girl. This case highlights the significant therapeutic dilemmas clinicians are faced with when dealing with conditions having an unknown natural history and unpredictable surgical outcomes, and reinforces the need for these patients to be managed by a multidisciplinary team approach.

ObjectivesThe lack of accurate measurement of hemodynamics and oxygen transport has limited our understanding of Norwood physiology and postoperative management. We used measured oxygen consumption to characterize hemodynamics and oxygen transport after the classic Norwood procedure.MethodsFourteen neonates had continuous respiratory mass spectrometry to measure oxygen consumption (VO2). Arterial, superior vena caval, and pulmonary venous saturations were measured at 2- to 4-hour intervals for 72 hours postoperatively. Systemic (Qs) and pulmonary (Qp) blood flows, systemic vascular resistance (SVR) and pulmonary vascular resistance inclusive of the Blalock–Taussig shunt (BT-PVR), systemic oxygen delivery (DO2), and the oxygen extraction ratio (ERO2) were calculated.ResultsQs and DO2 were low during the first 12 hours (1.8 ± 0.6 L·min−1·m−2 and 281 ± 86 mL·min−1·m−2 at the 12th hour, respectively) and increased over the study period (P < .05 for both). VO2 decreased markedly during the first 24 hours (101 ± 26 to 86 ± 16 mL·min−1·m−2, P < .0001). Consequently, ERO2 decreased significantly over the study, most rapidly during the first 24 hours (0.44 ± 0.11 to 0.28 ± 0.09, P < .0001). There was a close correlation of DO2 to SVR and to Qs (P < .0001 for both). There was no correlation of DO2 to BT-PVR (P = .14) or to Qp (P = .67). DO2 was closely correlated with hemoglobin value (P < .0001), weakly correlated with Pao2 (P = .0002), and not correlated with arterial oxygen saturation (P = .32).ConclusionsThere is wide variability of hemodynamics and oxygen transport after the Norwood procedure. The decrease in VO2 during the first 24 hours is the main contributor to improving the balance of oxygen transport. DO2 is most closely correlated to SVR and hemoglobin and weakly correlated to Pao2. It is not correlated to Qp. Postoperative management strategies to decrease VO2 and maintain a high hemoglobin level and a low SVR appear to be rational.

Objectives: To evaluate the clinical utility of near-infrared spectroscopic (NIRS) monitoring of cerebral (Sco 2 ) and splanchnic (Sso 2 ) oxygen saturations for estimation of systemic oxygen transport after the Norwood procedure. Methods: Sco 2 and Sso 2 were measured with NIRS cerebral and thoracolumbar probes (in humans). Respiratory mass spectrometry was used to measure systemic oxygen consumption (Vo 2 ). Arterial (Sao 2 ), superior vena caval (Svo2) and pulmonary venous oxygen saturations were measured at 2 to 4 h intervals to derive pulmonary (Qp) and systemic blood flow (Qs), systemic oxygen delivery (Do 2 ) and oxygen extraction ratio (ERo 2 ). Mixed linear regression was used to test correlations. A study of 7 pigs after cardiopulmonary bypass (study 1) was followed by a study of 11 children after the Norwood procedure (study 2). Results: Study 1 . Sco 2 moderately correlated with Svo 2 , mean arterial pressure, Qs, Do 2 and ERo 2 (slope 0.30, 0.64. 2.30, 0.017 and −32.5, p 2 , arterial oxygen pressure (Pao 2 ), haemoglobin and Vo 2 . Study 2 . Sco 2 correlated well with Svo 2 , Sao 2 , Pao 2 and mean arterial pressure (slope 0.43, 0.61, 0.99 and 0.52, p 0.05). Sco 2 correlated weakly with Vo 2 (slope −0.07, p = 0.05) and moderately with Qs, Do 2 and ERo 2 (slope 3.2, 0.03, −33.2, p 2 showed similar but weaker correlations. Conclusions: Sco 2 and Sso 2 may reflect the influence of haemodynamic variables and oxygen transport after the Norwood procedure. However, the interpretation of NIRS data, in terms of both absolute values and trends, is difficult to rely on clinically.

Clinical Summary A 10-year-old girl, weighing 32 kg, with no medical history was transferred from a regional center with Staphylococcal aureus native mitral valve endocarditis complicated by cerebral infarction and hemorrhage in both frontal lobes, the right thalamus, and possibly the left caudate nucleus and thalamus. She deteriorated day 2 of admission with chorda rupture, and an emergency mitral valve operation was indicated. Standard anesthesia was administered. Preanesthesia inotropes were dopamine 10 g · kg 1 · min 1 and epinephrine 0.5 g · kg 1 · min . A bolus dose of 2 mg/kg of methylene blue was given. On commencement of cardiopulmonary bypass, a further 2 mg/kg and an infusion of 1 mg · kg 1 · h 1 of methylene blue was commenced. An abscess around the mitral valve annulus was resected and replaced with a porcine valve. The dilated left atrium and ventricle were reinforced with a bovine pericardial patch. During bypass, mean arterial pressure was maintained between 30 and 40 mm Hg. Cerebral oximetry ranged from 76% to 93% prebypass during methylene blue infusion and from 66% to 82% during bypass. Surprisingly, methylene blue did not seem to affect oximetry readings. The CPB time was 133 minutes, and the aortic crossclamp time was 115 minutes. Weaning from bypass required epinephrine 0.05 to 0.1 g · kg 1 · min , norepinephrine 0.1 g · kg 1 · min , vasopressin 0.0001 to 0.0003 g · kg 1 · min , milrinone 0.33 g · kg 1 · min , and methylene blue infusion at 1 mg · kg 1 · h 1 to achieve a systolic arterial pressure of 70 to 80 mm Hg and diastolic pressure range of 30 to 50 mm Hg. The patient was transferred to the critical care unit and extubated 6 days later. The methylene blue infusion was ceased on arrival to the unit. Epinephrine and norepinephrine were ceased the day after surgery, vasopressin was ceased on postoperative day 2, and milrinone was ceased on day 8.

Background— After modifications in our perioperative management protocol, we have observed a decrease in sudden circulatory collapse after the Norwood operation. The current study examines early outcomes after the Norwood operation in our unit in an attempt to identify variables that may have altered the risk of unexpected circulatory collapse. Methods and Results— We studied 105 consecutive neonates who underwent a Norwood operation in our institution. Our treatment protocol has changed in the past 3 years to include the use of alpha-blockade with phenoxybenzamine (POB) for systemic afterload reduction and selective cerebral perfusion. Forty-eight infants had selective cerebral perfusion. Forty-two infants received POB. Sixty patients had hypoplastic left heart syndrome. There was no difference in age, diagnosis, number of neonates with weight P P P P Conclusion— Recent changes in our treatment protocol have resulted in a decrease incidence of sudden circulatory collapse after the Norwood operation. Optimal surgical technique is the most important predictor of early survival. The use of aggressive afterload reduction with POB reduced the risk of early sudden arrest.

ObjectivesWe investigated the effects of different CO2tensions on oxygenation, pulmonary blood flow (Qp), cerebral blood flow, and systemic blood flow (Qs) after the bidirectional superior cavopulmonary anastomosis (BCPA).BackgroundHypoxemia refractory to management of a high pulmonary vascular resistance index (PVRI) may complicate recovery from the BCPA.MethodsAfter BCPA, CO2was added to the inspired gas of mechanically ventilated patients. The Qp, Qs, PVRI, and systemic vascular resistance index (SVRI) were calculated from oxygen consumption, intravascular pressures, and oxygen saturations. Cerebral blood flow was estimated by near infrared spectroscopy and transcranial Doppler.ResultsIn nine patients (median age 7.1, range 2 to 23 months), arterial oxygen tension increased significantly (p < 0.005) from 36 ± 6 mm Hg to 44 ± 6 to 50 ± 7 mm Hg at arterial carbon dioxide tensions (PaCO2) of 35, 45, and 55 mm Hg, respectively and decreased to 40 ± 8 mm Hg at PaCO240 mm Hg. At a PaCO2of 55 and 45 compared with 35 mm Hg, Qp, cerebral blood flow, and Qs increased significantly, PVRI, Qp/Qs, and the ratio of Qp to inferior vena caval blood flow were unchanged, but SVRI decreased.ConclusionsWe have demonstrated that after the BCPA, systemic oxygenation, Qp, Qs, and cerebral blood flow increased and SVRI decreased at CO2tensions of 45 and 55 mm Hg compared with 35 mm Hg. We suggest that hypoxemia after the BCPA is ameliorated by a higher PaCO2and that low PaCO2or alkalosis may be detrimental. Hypercarbic management strategies may allow earlier progression to the BCPA, which may contribute to reducing the interval morbidity in patients with a functional single ventricle.

Nitric oxide is an endothelium-derived vasodilator. Cardiopulmonary bypass may induce transient pulmonary endothelial dysfunction with decreased nitric oxide release that contributes to postoperative pulmonary hypertension and lung injury. Exhaled nitric oxide levels may reflect, in part, endogenous production from the pulmonary vascular endothelium.We measured exhaled nitric oxide levels before and 30 minutes after cardiopulmonary bypass in 30 children with acyanotic congenital heart disease and left-to-right intracardiac shunts undergoing repair.Exhaled nitric oxide levels decreased by 27.6%+/-5.6% from 7+/-0.8 to 4.4+/-0.5 ppb (p0.05) 30 minutes after cardiopulmonary bypass despite a reduction in hemoglobin concentration.The decrease in exhaled nitric oxide levels suggests reduced nitric oxide synthesis as a result of pulmonary vascular endothelial or lung epithelial injury. This may explain the efficacy of inhaled nitric oxide in the treatment of postoperative pulmonary hypertension. Furthermore, strategies aimed at minimizing endothelial dysfunction and augmenting nitric oxide production during cardiopulmonary bypass may decrease the incidence of postoperative pulmonary hypertension. Exhaled nitric oxide levels may be useful to monitor both cardiopulmonary bypass-induced endothelial injury and the effect of strategies aimed at minimizing such injury.

Chest wall motion during anaesthesia may differ from the awake state because of the effect of anaesthetic agents on the muscles of respiration. The purpose of this study was twofold (1) to describe the pattern of chest wall motion in infants and children during halothane anaesthesia (HA) using respiratory inductive plethysmography (RIP) and (2) to calibrate the voltage output of RIP in units of volume. Seven infants (2.3 ±1.7 mo, 5.9 ±0.7 kg) and five children (2.9 ±1.1 yr, 15.5 ±1.5 kg) were studied. Since results in both age groups were qualitatively similar they are presented as a single group. Respiratory excursions of the rib cage (RC) and abdomen (ABD) were measured using RIP. Airflow was measured with a pneumotachograph. During spontaneous breathing the analogue signals of airflow, pressure, RC and ABD were recorded. Measurements were taken during (1) halothane anaesthesia and (2) during emergence from anaesthesia. The XY plots of the RC and ABD signals were plotted for each period. In addition the voltage output of the respiratory excursions of the RC and ABD signals was converted to units of volume using the simultaneous solution of equation method. The accuracy of conversion factors was validated by regression analysis of the predicted and measured tidal volume using breaths sampled at random throughout the entire period of study. Regression analysis of this relationship gave a slope between 0.85 and 1.15 (r2 value > 0.7) in five of the twelve patients. The pattern of chest wall motion in the X Y plots showed synchronous motion between RC and ABD signals during HA in nine of the twelve patients. Three patients showed paradoxical inward motion of the RC during inspiration. This finding differs from that of previous studies which showed asynchrony between the RC and ABD signals during HA.

ObjectivesWe sought to determine whether infants (younger than 1 year old) had similar clinical benefits with individualized anticoagulation management as older children and adult undergoing cardiopulmonary bypass (CPB).BackgroundIndividualized heparin and protamine management in older children and adults undergoing CPB has been associated with improved clinical outcomes.MethodsNinety infants younger than 1 year of age undergoing CPB were enrolled in a randomized, controlled trial comparing weight-based anticoagulation management using activated clotting time (ACT) to individualized management with Hemostasis Management System Plus. Manufacturer's guidelines were followed for the first 33 patients. A modified protocol was used for the last 57 patients with adjustments for coagulation system immaturity and hemodilution on CPB.ResultsThe hemostasis management system (HMS) device consistently underestimated plasma anti-Xa levels, leading to an overestimated required heparin dose. After a blinded interim analysis revealed poor outcomes in the experimental HMS group using manufacturer guidelines, the safety committee suspended the study pending protocol modifications. The use of the HMS device following the modified protocol resulted in more stable anti-Xa levels during CPB with improved post-operative outcomes including reduced need for transfusions (71 ml/kg vs. 80 ml/kg; p = 0.003), ventilation time (33 h vs. 49 h; p = 0.04), intensive care (88 h vs. 99 h; p = 0.003), and hospital length of stay (192 h vs. 216 h; p < 0.001), compared with the weight-based protocol.ConclusionsThis study supports the use of the HMS device, with a modified protocol for infants younger than 1 year of age, for anticoagulation management during CPB. Clinical guidelines for the use of the HMS device should be modified for infants younger than 1 year of age.

Objectives: We have shown that exhaled nitric oxide levels decrease after surgical closure of congenital left-to-right cardiac shunts. It remains unclear whether the change in exhaled nitric oxide levels reflects endothelial injury caused by the use of cardiopulmonary bypass or the decrease in pulmonary blood flow attendant on shunt closure. Transcatheter atrial septal defect closure permits shunt closure without the use of cardiopulmonary bypass. Therefore we compared changes in exhaled nitric oxide levels after surgical and transcatheter device closure of atrial septal defects. Methods: We enrolled sequentially 30 children undergoing atrial septal defect closure. Fifteen patients (age range, 0.4-16 years; median age, 6.5 years) underwent surgical atrial septal defect closure with cardiopulmonary bypass, and 15 patients (age range, 4-17 years; median age, 8.4 years) had device closure of the atrial septal defect in the catheterization laboratory. We measured nitric oxide levels in end-tidal expiratory gas with a rapid-response chemiluminescent analyzer before and after atrial septal defect closure. Results: After surgical repair of the atrial septal defect, exhaled nitric oxide decreased by 21%, from 10.9 ± 4.4 to 8.4 ± 3.3 ppb (P