Dose rationale for the use of meropenem/vaborbactam combination in paediatric patients with Gram-negative bacterial infections.

AIMS: Meropenem/vaborbactam combination is approved in adults by FDA and EMA for complicated urinary tract infections and by EMA also for other Gram-negative infections. We aimed to characterise the pharmacokinetics of both moieties in an ongoing study in children and use a model-based approach to inform adequate dosing regimens in paediatric patients. METHODS: Over 4196 blood samples of meropenem and vaborbactam (n = 414 subjects) in adults, together with 114 blood samples (n = 39) in paediatric patients aged 3 months to 18 years were available for this analysis. Data were analysed using a population with prior information from a pharmacokinetic model in adults to inform parameter estimation in children. Simulations were performed to assess the suitability of different dosing regimens to achieve adequate probability of target attainment (PTA). RESULTS: Meropenem/vaborbactam PK was described with two-compartment models with first-order elimination. Body weight and CLcr were significant covariates on the disposition of both drugs. A maturation function was evaluated to explore changes in clearance in neonates. PTA ≥90% was derived for children aged ≥3 months after 3.5-h IV infusion of 40 mg/kg Q8h of both meropenem and vaborbactam and 2 g/2 g for those ≥50 kg. Extrapolation of disposition parameters suggest that adequate PTA is achieved after a 3.5-h IV infusion of 20 mg/kg for neonates and infants (3 months). CONCLUSIONS: An integrated analysis of adult and paediatric data allowed accurate description of sparsely sampled meropenem/vaborbactam PK in paediatric patients and provided recommendations for the dosing in neonates and infants (3 months).

Delirium duration and mortality in lightly sedated, mechanically ventilated intensive care patients.

OBJECTIVES: To determine the relationship between the number of delirium days experienced by intensive care patients and mortality, ventilation time, and intensive care unit stay. DESIGN: Prospective cohort analysis. SETTING: Patients from 68 intensive care units in five countries. PATIENTS: Three hundred fifty-four medical and surgical intensive care patients enrolled in the SEDCOM (Safety and Efficacy of Dexmedetomidine Compared with Midazolam) trial received a sedative study drug and completed at least one delirium assessment. INTERVENTIONS: Sedative drug interruption and/or titration to maintain light sedation with daily arousal and delirium assessments up to 30 days of mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: The primary outcome was all-cause 30-day mortality. Multivariable analysis using Cox regression incorporating delirium duration as a time-dependent variable and adjusting for eight relevant baseline covariates was conducted to quantify the relationship between number of delirium days and the three main outcomes. Overall, delirium was diagnosed in 228 of 354 patients (64.4%). Mortality was significantly lower in patients without delirium compared to those with delirium (15 of 126 [11.9%] vs. 69 of 228 [30.3%]; p<.001). Similarly, the median time to extubation and intensive care unit discharge were significantly shorter among nondelirious patients (3.6 vs. 10.7 days [p<.001] and 4 vs. 16 days [p<.001], respectively). In multivariable analysis, the duration of delirium exhibited a nonlinear relationship with mortality (p=.02), with the strongest association observed in the early days of delirium. In comparison to 0 days of delirium, an independent dose-response increase in mortality was observed, which increased from 1 day of delirium (hazard ratio, 1.70; 95% confidence interval, 1.27-2.29; p<.001), 2 days of delirium (hazard ratio, 2.69; confidence interval, 1.58-4.57; p<.001), and ≥3 days of delirium (hazard ratio, 3.37; confidence interval, 1.92-7.23; p<.001). Similar independent relationships were observed between delirium duration and ventilation time and intensive care length of stay. CONCLUSIONS: In ventilated and lightly sedated intensive care unit patients, the duration of delirium was the strongest independent predictor of death, ventilation time, and intensive care unit stay after adjusting for relevant covariates.

A cost-minimization analysis of dexmedetomidine compared with midazolam for long-term sedation in the intensive care unit.

OBJECTIVE: To compare the intensive care unit costs and determine factors influencing these costs in mechanically ventilated patients randomized to dexmedetomidine or midazolam by continuous infusion. DESIGN: Cost minimization analysis of a double-blind, multicenter clinical trial randomizing patients 2:1 to receive dexmedetomidine or midazolam from the institutional perspective. SETTING: Sixty-eight intensive care units in the United States, Australia, New Zealand, Brazil, and Argentina. PATIENTS: A total of 366 intubated intensive care unit patients anticipated to require sedation for >24 hrs. MEASUREMENTS AND MAIN RESULTS: Intensive care unit resource use was compared within the two treatment arms, using the U.S. representative costs for these resources. The analyses characterized patient costs from start of study drug until intensive care unit discharge including costs associated with the intensive care unit stay, costs during mechanical ventilation, study drug acquisition cost, and costs of treating adverse drug reactions probably or possibly related to study drugs. Blinded to treatment group, costs were calculated using Medicare reimbursement schedules, average IMS drug costs, expert opinion, and peer-reviewed literature. Censored lengths of intensive care unit stay and mechanical ventilation were imputed, using a nonparametric adjustment algorithm. Crude and multivariate median regressions were performed to relate intensive care unit cost and treatment. Including drug acquisition cost, sedation with dexmedetomidine was associated with a median total intensive care unit cost savings of $9679 (confidence interval, $2314-$17,045) compared with midazolam. The primary cost drivers were reduced costs of intensive care unit stay (median savings, $6584, 95% confidence interval, $727-$12,440) and reduced costs of mechanical ventilation (median savings, $2958, 95% confidence interval, $698-$5219). CONCLUSIONS: Continuous sedation with dexmedetomidine results in significantly lower total intensive care unit costs compared with midazolam infusion for intensive care unit sedation, primarily due to decreased intensive care unit stay costs and reduced mechanical ventilation costs.

A Phase IIIb, randomized, double-blind, placebo-controlled, multicenter study evaluating the safety and efficacy of dexmedetomidine for sedation during awake fiberoptic intubation.

GABA-mediated sedatives have respiratory depressant properties that may be detrimental in patients with difficult airways. In this randomized, double-blind, multicenter, Phase IIIb Food and Drug Administration study, safety and efficacy of dexmedetomidine compared with placebo were evaluated as the primary sedative for awake fiberoptic intubation (AFOI). Patients were randomized to receive dexmedetomidine or saline. Patients were sedated with dexmedetomidine or rescue midazolam to achieve targeted sedation (Ramsay Sedation Scale ≥ 2) before topicalization and throughout AFOI. Primary efficacy endpoint was percentage of patients requiring rescue midazolam; secondary efficacy endpoints were total dose of rescue midazolam, percentage requiring additional rescue nonmidazolam medications, anesthesiologist's assessment of ease of subject care, and patient recall and satisfaction 24 hours postoperatively. Less rescue midazolam was required to maintain Ramsay Sedation Scale ≥2 (47.3% vs. 86.0%, P < 0.001), and supplemental midazolam dose was lower (1.07 ± 1.5 mg vs. 2.85 ± 3.0 mg, P < 0.001) with dexmedetomidine compared with placebo. More Mallampati Class IV patients treated with dexmedetomidine were successfully intubated without midazolam than with placebo (66.7% vs. 8.3%, P = 0.009). Dexmedetomidine decreased blood pressure and heart rate compared with placebo patients sedated with midazolam. Patients and anesthesiologists showed favorable satisfaction responses in both groups. Adverse events and patient recall were similar in both groups. Dexmedetomidine is effective as the primary sedative in patients undergoing AFOI. Some patients may require small supplemental doses of midazolam, in addition to dexmedetomidine, to achieve sufficient sedation for AFOI. Dexmedetomidine provides another AFOI option for sedation of patients with difficult airways.

Monitored anesthesia care with dexmedetomidine: a prospective, randomized, double-blind, multicenter trial.

BACKGROUND: Dexmedetomidine (DEX) is increasingly being used as a sedative for monitored anesthesia care (MAC) because of its analgesic properties, "cooperative sedation," and lack of respiratory depression. In this randomized, multicenter, double-blind, Phase III Food and Drug Administration study, we evaluated the safety and efficacy of two doses of DEX for sedation of patients undergoing a broad range of surgical or diagnostic procedures requiring MAC. METHODS: Three hundred twenty-six patients were randomized 2:2:1 to DEX 0.5 microg/kg, DEX 1 microg/kg, or saline placebo initial loading dose, followed by a maintenance infusion of 0.2-1.0 microg x kg(-1) x h(-1) of DEX (or equivalent volume of saline) titrated to a targeted level of sedation (< or = 4 on the Observer's Assessment of Alertness/Sedation Scale [OAA/S]). Study drug was started at least 15 min before placement of regional or local anesthetic block. Midazolam was given for OAA/S > 4 and fentanyl for pain. The primary end-point was the percentage of patients not requiring rescue midazolam. RESULTS: Significantly fewer patients in the 0.5- and 1-microg/kg DEX groups required supplemental midazolam compared with placebo (59.7% [80/134], 45.7% [59/129] vs 96.8% [61/63], respectively; P < 0.001) and at lower doses to achieve an OAA/S < or = 4 before and during surgery compared with the saline group (1.4 and 0.9 mg vs 4.1 mg, respectively; P < 0.001, each group compared with placebo). Both DEX groups required significantly less fentanyl (84.8 and 83.6 microg vs 144.4 microg, respectively; P < 0.001, for both DEX groups versus placebo) for all surgical subtypes. Anesthesiologists indicated significantly increased ease of achieving and maintaining targeted sedation in both DEX groups compared with placebo with midazolam (P < 0.001). Patient satisfaction was significantly higher with DEX (P < or = 0.009, both groups versus placebo). Common adverse events with DEX were protocol-defined bradycardia and hypotension that were predominately mild to moderate in severity. The incidence of clinically significant respiratory depression (defined as a respiratory rate of < 8 or an oxygen saturation of < 90%) was lower in DEX-treated patients (P = 0.018, for both groups versus placebo). CONCLUSIONS: DEX is an effective baseline sedative for patients undergoing MAC for a broad range of surgical procedures providing better patient satisfaction, less opioid requirements, and less respiratory depression than placebo rescued with midazolam and fentanyl.

Dosing of clopidogrel for platelet inhibition in infants and young children: primary results of the Platelet Inhibition in Children On cLOpidogrel (PICOLO) trial.

BACKGROUND: Infants and young children with certain types of heart disease are at increased risk for thromboses. Clopidogrel 75 mg/d is used in adults to prevent thrombotic events. The dose to achieve similar platelet inhibition in children is unknown. The objectives of the present study were (1) to determine the dose of clopidogrel needed in infants and young children to achieve a mean 30% to 50% inhibition of 5-micromol/L ADP-induced platelet aggregation (ie, inhibition similar to that observed with 75 mg in adults) and (2) to assess the safety and tolerability of clopidogrel in infants and young children. METHODS AND RESULTS: We performed a prospective, multicenter, randomized, placebo-controlled trial evaluating the pharmacodynamics of clopidogrel in children (0 to 24 months) with a cardiac condition at risk for arterial thrombosis. Patients were randomized to clopidogrel versus placebo in a 3:1 ratio in 4 sequential groups (0.01, 0.10, 0.20, and 0.15 mg/kg) for > or = 7 and < or = 28 days. Platelet aggregation was assessed at baseline and steady state by light-transmission aggregometry. Of 116 patients enrolled, 92 (50% neonates, 50% infants/toddlers) were randomized, and 73 completed the study. A total of 79% of the randomized and treated patients were taking aspirin. Compared with placebo, clopidogrel 0.20 mg x kg(-1) x d(-1) resulted in a mean 49.3% (95% confidence interval 25.7% to 72.8%) inhibition of the maximum extent of platelet aggregation and a mean 43.9% (95% confidence interval 18.6% to 69.2%) inhibition of the rate of platelet aggregation. There was marked interpatient variability in the degree of platelet aggregation inhibition within each treatment-dose group and age group. No serious bleeding events occurred. CONCLUSIONS: Clopidogrel 0.20 mg x kg(-1) x d(-1) in children 0 to 24 months of age achieves a platelet inhibition level similar to that in adults taking 75 mg/d. Clopidogrel is well tolerated in infants and young children at this dose.

Dexmedetomidine vs midazolam for sedation of critically ill patients: a randomized trial.

CONTEXT: Gamma-aminobutyric acid receptor agonist medications are the most commonly used sedatives for intensive care unit (ICU) patients, yet preliminary evidence indicates that the alpha(2) agonist dexmedetomidine may have distinct advantages. OBJECTIVE: To compare the efficacy and safety of prolonged sedation with dexmedetomidine vs midazolam for mechanically ventilated patients. DESIGN, SETTING, AND PATIENTS: Prospective, double-blind, randomized trial conducted in 68 centers in 5 countries between March 2005 and August 2007 among 375 medical/surgical ICU patients with expected mechanical ventilation for more than 24 hours. Sedation level and delirium were assessed using the Richmond Agitation-Sedation Scale (RASS) and the Confusion Assessment Method for the ICU. INTERVENTIONS: Dexmedetomidine (0.2-1.4 microg/kg per hour [n = 244]) or midazolam (0.02-0.1 mg/kg per hour [n = 122]) titrated to achieve light sedation (RASS scores between -2 and +1) from enrollment until extubation or 30 days. MAIN OUTCOME MEASURES: Percentage of time within target RASS range. Secondary end points included prevalence and duration of delirium, use of fentanyl and open-label midazolam, and nursing assessments. Additional outcomes included duration of mechanical ventilation, ICU length of stay, and adverse events. RESULTS: There was no difference in percentage of time within the target RASS range (77.3% for dexmedetomidine group vs 75.1% for midazolam group; difference, 2.2% [95% confidence interval {CI}, -3.2% to 7.5%]; P = .18). The prevalence of delirium during treatment was 54% (n = 132/244) in dexmedetomidine-treated patients vs 76.6% (n = 93/122) in midazolam-treated patients (difference, 22.6% [95% CI, 14% to 33%]; P < .001). Median time to extubation was 1.9 days shorter in dexmedetomidine-treated patients (3.7 days [95% CI, 3.1 to 4.0] vs 5.6 days [95% CI, 4.6 to 5.9]; P = .01), and ICU length of stay was similar (5.9 days [95% CI, 5.7 to 7.0] vs 7.6 days [95% CI, 6.7 to 8.6]; P = .24). Dexmedetomidine-treated patients were more likely to develop bradycardia (42.2% [103/244] vs 18.9% [23/122]; P < .001), with a nonsignificant increase in the proportion requiring treatment (4.9% [12/244] vs 0.8% [1/122]; P = .07), but had a lower likelihood of tachycardia (25.4% [62/244] vs 44.3% [54/122]; P < .001) or hypertension requiring treatment (18.9% [46/244] vs 29.5% [36/122]; P = .02). CONCLUSIONS: There was no difference between dexmedetomidine and midazolam in time at targeted sedation level in mechanically ventilated ICU patients. At comparable sedation levels, dexmedetomidine-treated patients spent less time on the ventilator, experienced less delirium, and developed less tachycardia and hypertension. The most notable adverse effect of dexmedetomidine was bradycardia. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00216190 Published online February 2, 2009 (doi:10.1001/jama.2009.56).

Clinical outcomes of palliative surgery including a systemic-to-pulmonary artery shunt in infants with cyanotic congenital heart disease: does aspirin make a difference?

BACKGROUND: Aspirin (ASA) often is used to prevent thrombosis in infants with congenital heart disease after placement of a systemic-to-pulmonary artery shunt, but its effect on outcomes is unknown. METHODS AND RESULTS: The present multicenter study prospectively collected data on 1-year postoperative rates of death, shunt thrombosis, or hospitalization age <4 months for bidirectional Glenn/hemi-Fontan surgery in 1004 infants. The use and dose of ASA were recorded. Kaplan-Meier event rates were calculated for each event and the composite outcome, and a Cox regression model was constructed for time to event. Model terms were ASA use and type of surgery, with adjustment for age at surgery. Diagnoses were hypoplastic left heart syndrome (n=346), tricuspid atresia (n=103), tetralogy of Fallot (n=127), pulmonary atresia (n=177), heterotaxy syndrome (n=38), and other (n=213). There were 344 shunts placed without cardiopulmonary bypass (closed shunt), 287 shunts with bypass (open shunt), 323 Norwood procedures, and 50 Sano procedures. Overall, 80% of patients received ASA. One-year postoperative events rates were high: 38% for the composite end point, 26% for death, and 12% for shunt thrombosis. After the exclusion of patients with early mortality, patients receiving ASA had a lower risk of shunt thrombosis (hazard ratio, 0.13; P=0.008) and death (closed shunt: hazard ratio, 0.41, P=0.057; open shunt: hazard ratio, 0.10, P<0.001; Norwood: hazard ratio, 0.34, P<0.001; Sano: hazard ratio, 0.68, P=NS) compared with those not receiving ASA. CONCLUSIONS: The morbidity and mortality for infants after surgical placement of a systemic-to-pulmonary artery shunt are high. ASA appears to lower the risk of death and shunt thrombosis in the present observational study.

NMDA receptor antibodies predict adverse neurological outcome after cardiac surgery in high-risk patients.

BACKGROUND AND PURPOSE: The goal of this study was to compare the predictive ability of S100B, N-methyl-D-aspartate (NMDA) receptor antibodies (NR2Ab) and C-reactive protein (CRP) for neurological deficits after cardiac surgery with cardiopulmonary bypass (CPB). METHODS: We investigated 557 high-risk adult patients who underwent coronary artery or valve replacement surgery using CPB as a substudy of a prospective, blinded, multicenter clinical trial. Serum concentrations of S100B (n=513 patients), NR2Ab (n=398) and CRP (n=510) were measured preoperatively, 24 and 48 hours after CPB. Neurological adverse events were assessed at baseline and postoperative days 1 and 2; neurocognitive function (mini-mental status examination) was assessed at baseline and on postoperative days 1, 7 and 28. RESULTS: Fifty-five (9.9%) patients had moderate or severe neurological adverse events (confusion/delirium, transient ischemic attack, or stroke) within 48 hours of CPB. Women had significantly more neurological complications than men (15.5% versus 7.8%; P=0.007). Ninety-six percent (24/25) of patients with NR2Ab concentrations > or =2.0 ng/mL preoperatively had neurological complications within 48 hours post-CPB, versus only 5.4% (20/373) of patients with NR2Ab concentrations <2.0 ng/mL, resulting in a 17.9-fold increase (95% CI, 11.6 to 27.6) in postoperative neurological complications for patients with high levels of NR2A antibodies. Preoperative serum S100B and CRP did not predict neurological complications from CPB. Decreased mini-mental status examination scores for orientation, attention and recall were associated with neurological adverse events early after CPB. CONCLUSIONS: Preoperative serum concentrations of NR2Ab, but not S100B or CRP, are predictive of severe neurological adverse events after CPB. Patients with a positive NR2Ab test (> or =2.0 ng/mL) preoperatively were nearly 18 times more likely to experience a postoperative neurological event than patients with a negative test (<2.0 ng/mL).

Soluble human complement receptor 1 limits ischemic damage in cardiac surgery patients at high risk requiring cardiopulmonary bypass.

BACKGROUND: This study was undertaken to determine whether soluble human complement receptor type 1 (TP10), a potent inhibitor of complement activation, would reduce morbidity and mortality in high-risk patients undergoing cardiac surgery on cardiopulmonary bypass (CPB). METHODS: This was a randomized multicenter, prospective, placebo-controlled, double-blind study in which 564 high-risk patients undergoing cardiac surgery on CPB received an intravenous bolus of TP10 (1, 3, 5, 10 mg/kg) or placebo immediately before CPB. The primary endpoint was the composite events of death, myocardial infarction (MI), prolonged (> or =24 hours) intra-aortic balloon pump support (IABP), and prolonged intubation. RESULTS: TP10 significantly inhibited complement activity after 10 to 15 minutes of CPB and this inhibition persisted for 3 days postoperatively. However, there was no difference in the primary endpoint between the 2 groups (33.7% placebo versus 31.4% TP10; P=0.31). The primary composite endpoint was, however, reduced in all male TP10 patients by 30% (P=0.025). TP10 reduced the incidence of death or MI in males by 36% (P=0.026), the incidence of death or MI in CABG males by 43% (P=0.043) and the need for prolonged IABP support in male CABG and valve patients by 100% (P=0.019). There was, however, no improvement seen in female TP10 patients. There were no significant differences in adverse events between the groups. CONCLUSIONS: TP10 effectively inhibits complement activation during CPB; however, this was not associated with an improvement in the primary endpoint of the study. Nevertheless, TP10 did significantly decrease the incidence of mortality and MI in male patients.

Serum creatinine and estimated creatinine clearance do not predict perioperatively measured creatinine clearance in neonates undergoing congenital heart surgery.

OBJECTIVE: To describe changes in creatinine clearance (CrCl) in a small group of neonates who underwent surgery for repair of transposition of the great arteries or palliation of hypoplastic left heart syndrome. To determine whether serum creatinine, urine output, or the Schwartz formula accurately predict measured CrCl in these patients. DESIGN: Prospective, randomized controlled trial with subsequent extraction of information regarding renal function from the database. SETTING: A 14-bed pediatric intensive care unit in a children's hospital. PATIENTS: A total of 14 neonates (hypoplastic left heart syndrome, 6; transposition of the great arteries, 8). MEASUREMENTS: Demographic information, urine output, serum creatinine, and 24-hr CrCl preoperatively and postoperatively on days 1 and 2. MAIN RESULTS: Weight, age, and body surface area were 3.3 +/- 0.6 kg, 8.2 +/- 6.9 days, and 0.2 +/- 0.02 m2, respectively. Urine output increased from 1.8 +/- 0.5 mL x kg(-1) x hr(-1) preoperatively to 2.4 +/- 0.8 mL x kg(-1) x hr(-1) on postoperative day 1 (p = .02) and 2.8 +/- 1.1 mL x kg(-1) x hr(-1) on postoperative day 2 (p = .007). Serum creatinine changed from 0.64 +/- 0.15 mg/dL preoperatively to 0.72 +/- 0.40 mg/dL on postoperative day 1 (p = .4, not significant) to 0.78 +/- 0.41 mg/dL on postoperative day 2 (p = .17, not significant). Measured CrCl changed from 22.8 +/- 9.4 mL x min(-1) x 1.73 m(-2) preoperatively to 25.1 +/- 31 mL x min(-1) x 1.73 m(-2) on postoperative day 1 (p = .77, not significant) and 24.9 +/- 19.9 on postoperative day 2 (p = .69, not significant). No difference in measured CrCl was noted based on hypoplastic left heart syndrome vs. transposition of the great arteries. Median overestimation of CrCl by the Schwartz equation was 58% preoperatively, 78% on postoperative day 1, and 53% on postoperative day 2. Clinically significant correlations were not noted between measured CrCl and serum creatinine or urine production preoperatively, on postoperative day 1, or on postoperative day 2. Bland-Altman plot demonstrated that the Schwartz equation was a biased and imprecise estimate of CrCl at all three time points. CONCLUSIONS: Perioperative CrCl is unpredictable in neonates with transposition of the great arteries and hypoplastic left heart syndrome. Serum creatinine, urine output, and the Schwartz formula do not accurately predict CrCl. Reliance on estimates of CrCl could result in toxic concentrations of drugs eliminated by the kidneys.

A phase 2 prospective, randomized, double-blind trial comparing the effects of tranexamic acid with ecallantide on blood loss from high-risk cardiac surgery with cardiopulmonary bypass (CONSERV-2 Trial).

OBJECTIVE: Ecallantide is a recombinant peptide in the same class as aprotinin that inhibits plasma kallikrein, a major component of the contact coagulation and inflammatory cascades. Therefore, ecallantide was expected to reduce blood loss associated with cardiac surgery requiring cardiopulmonary bypass. METHODS: This prospective multinational, randomized, double-blind trial enrolled patients undergoing cardiac surgery using cardiopulmonary bypass for procedures associated with a high risk of bleeding. Patients were randomly assigned to ecallantide (n = 109) or tranexamic acid (high dose, n = 24; low dose, n = 85). Efficacy was assessed from the volume of packed red blood cells administered within the first 12 hours after surgery. RESULTS: The study was terminated early after the independent data safety and monitoring board observed a statistically significantly higher 30-day mortality in the ecallantide group (12%) than in the tranexamic acid groups (4%, P = .041). Patients receiving ecallantide received more packed red blood cells within 12 hours of surgery than tranexamic acid-treated patients: median = 900 mL (95% confidence interval, 600-1070) versus 300 mL (95% confidence interval, 0-523) (P < .001). Similar differences were seen at 24 hours and at discharge. Patients treated with the higher tranexamic acid dose received less packed red blood cells, 0 mL (95% confidence interval, 280-600), than the group treated with the lower dose, 400 mL (95% confidence interval, 0-400) (P = .008). No deaths occurred in the higher dose tranexamic acid group. CONCLUSIONS: Ecallantide was less effective at reducing perioperative blood loss than tranexamic acid. High-dose tranexamic acid was more effective than the low dose in reducing blood loss.

A glial-derived protein, S100B, in neonates and infants with congenital heart disease: evidence for preexisting neurologic injury.

UNLABELLED: The glial-derived protein S100B is a serum marker of cerebral ischemia and correlates with negative neurological outcome after cardiopulmonary bypass (CPB) in adults. We sought to characterize the S100B release pattern before and after CPB in neonates and infants with congenital heart disease and correlate it with surgical mortality. Serum was collected before surgery and at 24 postoperative h from 109 neonates and infants with congenital heart disease. All patients had presurgical transthoracic echocardiograms and CPB with or without hypothermic circulatory arrest. S100B concentrations were determined using a two-site immunoluminometric assay (Sangtec 100). Thirty-day surgical mortality was observed. All neonates had significantly increased S100B concentrations before surgery that decreased by 24 postoperative h. Preoperative S100B concentrations in 32 neonates with hypoplastic left heart syndrome correlated inversely with the forward flow and size of the ascending aorta and postoperative mortality (r(2) = -0.63; P = 0.03). Among infants, increased pulmonary blood flow was associated with higher S100B levels before surgery than cyanosis. There was no correlation with postoperative S100B and time on CPB, hypothermic circulatory arrest, or 30-day surgical mortality. In conclusion, preoperative S100B concentrations correlate inversely with the size of the ascending aorta in hypoplastic left heart syndrome and may serve as a marker for preexisting brain injury and mortality. IMPLICATIONS: Neonates with hypoplastic left heart syndrome and no forward flow in the ascending aorta may have brain injury at birth before heart surgery.

Increased transcription factor expression and permeability of the blood brain barrier associated with cardiopulmonary bypass in lambs.

BACKGROUND: The pathophysiology of neurocognitive dysfunction and developmental delay after cardiopulmonary bypass (CPB) in infants is not known. It is known that head trauma, stroke, and seizures cause dysfunction of the blood brain barrier (BBB) that is associated with increased inducible transcription factor gene expression in the cells of the barrier. The purpose of this study was to determine the effects of CPB and hypothermic circulatory arrest on expression of the transcription factor FOS and the function of the BBB in an infant animal model. METHODS: Infant lambs (n = 36; 10-12 days) were exposed to 0, 15, 30, 60, or 120 minutes of normothermic (38 degrees C) CPB or 2 hours of hypothermic circulatory arrest at 16 degrees C. After terminating bypass 15 animals had their brains perfusion-fixed and removed for immunohistochemical analysis of expression of the transcription factor FOS. The other animals were perfused with fluorescent albumin to visualize the brain microvasculature. Brain sections were analyzed with a laser scanning confocal microscope. RESULTS: Control animals (n = 6, sham operated and cannulated) exhibited normal vasculature with negligible leakage and no FOS protein expression in neurons or endothelial cells anywhere in the brain. Significant FOS expression in barrier-associated structures including the blood vessels, choroid plexus, and ependyma but not neurons occurred at all times on bypass. CPB caused leakage of fluorescent albumin from blood vessels in all animals. Two hours of normothermic CPB (n = 4) caused significant (p < 0.01) leakage in the cerebellum, cortex, hippocampus, and corpus callosum. Animals exposed to circulatory arrest experienced severe leakage throughout the brain (p < 0.001) and FOS expression in all cells. CONCLUSIONS: These experiments indicate that the BBB is dysfunctional after all time points on normothermic CPB, BBB dysfunction is worsened by hypothermic circulatory arrest, and BBB dysfunction is associated with intense molecular activity within the barrier-forming cells. Dysfunction of the BBB may contribute to neurologic complications after heart surgery.