Effects of Fibrinogen Concentrate Supplementation on Postoperative Bleeding in Infants Undergoing Complex Cardiac Surgery.

The use of allogeneic blood products to restore hemostasis during pediatric cardiac surgery is associated with major risks. Consequently, there has been a growing interest in new patient blood management strategies, such as those based on the use of fibrinogen concentrate (FC). Accumulating evidence has shown FC supplementation to be safe and effective. Nevertheless, no guidelines are available on using FC in the pediatric setting, and few objective evaluations have been provided in clinical practice. The endpoint of this monocenter retrospective study was the hemostatic effect of additional FC in infants undergoing complex cardiac surgery with cardiopulmonary bypass to manage persistent clinically relevant bleeding. After weaning from cardiopulmonary bypass and after protamine administration, patients were transfused with conventional allogeneic products such as packed red blood cells, fresh frozen plasma (FFP), and platelets. In the case of redo surgery, according to the institutional protocol, patients also received tranexamic acid. In case of clinically persistent relevant bleeding, according to the anesthesiologist's judgment and thromboelastography, patients received FC supplementation (group with FC) or further FFP transfusions without receiving FC supplementation (group without FC). The primary endpoint was the hemostatic effects of FC. Secondary endpoints were the functional hypofibrinogenemia threshold value (expressed as maximum amplitude fibrinogen, MA-Fib) and postoperative MA-Fib, fibrinogenemia, intraoperative transfusions, and adverse events (AEs). In total, 139 patients who underwent cardiac surgery with CPB and aged less than 2 years were enrolled: 70 patients received allogeneic blood products and FC supplementation (group FC); 69 patients received allogeneic products without FC supplementation (group without FC). Patients that received FC supplementation were characterized by a significantly longer time of extracorporeal circulation (p < 0.001) and aortic cross-clamping (p < 0.001), a significantly lower minimum temperature (p = 0.011), increased use of concentrated prothrombin complex (p = 0.016) and tranexamic acid (p = 0.010), and a significantly higher amount of packed red blood cells, platelets (p < 0.001) and fresh frozen plasma (p = 0.03). Postoperative bleeding and severe bleeding were not statistically different between patients treated with FC and those not treated with FC supplementation (p = 0.786 and p = 0.695, respectively); after adjustment, a trend toward reduced bleeding can be observed with FC (p = 0.064). Overall, 88% of patients with severe bleeding had MA-Fib < 10 mm; a moderate association between severe bleeding and MA-Fib (odds ratio 1.7, 95% CI 0.5-6.5, p = 0.425) was found. Increased MA-Fib and postoperative fibrinogen were higher in the FC group (p = 0.003 and p < 0.001, respectively) than in FFP. AEs in the FC group were comparable to those observed in less complicated surgeries. Our results suggest a potential role of FC in complex surgery in maintaining postoperative bleeding at a level comparable to less complicated surgical procedures and favoring the increase in postoperative MA-Fib and fibrinogen.

Diagnostic Agreement Between TEG5000 and TEG6S in the Assessment of Hemostasis in Pediatric Cardiac Surgery: A Prospective Non-inferiority Study.

Thromboelastography (TEG) is a point-of-care test (POCT) used to analyze the hemostatic properties of whole blood. TEG® 5000and TEG® 6s (Haemonetics Corp, USA) measure the same parameters describing clot viscoelasticity using different methodologies. The purpose of this study was to evaluate agreement between TEG5000 and TEG6s measurements. We analyzed prospectively collected tests resulting from paired blood samples in cardiac surgery pediatric patients at one hour (T0) and 24 h (T1) postoperatively. Each citrated sample was utilized for TEG® 5000 and TEG ®6s. Six specific TEG parameters were analyzed and compared: R kaolin time (RK), R kaolin heparinase (RKH) time, K kaolin time (KK), K kaolin heparinase time KH (KKH), Maximum Amplitude kaolin (MAK), Maximal Amplitude Kaolin Heparinase (MAKH). We enrolled 30 patients. Median (interquartile range) patients' age was 206 (20-597) days. All surgical patients underwent correction except 5 who were palliated. At T0, RK and RKH showed an average (standard deviation) % bias of 15.8 (31) and 16.1 (28), respectively, with similar results at T1. A % bias of -6 (23) and - 6 [15] in MAK was found at T0 and T1, respectively. Similarly, MAKH % bias was 1.5 (22) and 7.6 (29) at T0 and T1, respectively. At both timepoints, low % biases (< ± 6%) were demonstrated in KK and KKH. All parameters showed improved coagulation from T0 to T1, but without significant interaction between type of device and time. Analysis of the entire pool of 60 paired samples showed no agreement in diagnostic performance (within the range vs. outside the range) in 12 (20%), 5 (9.8%), 1 (1.7%), 4 (7.8%), 9 (15%), and 5 (9.8%) cases for RK, RKH, MAK, MAKH, KK and KKH, respectively. We observed substantial agreement in MAK and KK in a cohort of pediatric patients undergoing uncomplicated cardiac surgery. Our findings suggest that TEG®5000 and TEG®6s are interchangeable for assessing these parameters.

Vancomycin concentrations during cardiopulmonary bypass in pediatric cardiac surgery: a prospective study.

INTRODUCTION: Few data are available regarding intraoperative plasma concentrations of vancomycin administered as prophylaxis in pediatric cardiac surgery. The aims of this study were to investigate during pediatric cardiac surgery with cardiopulmonary bypass(CPB) the attainment of the area-under-the-curve of the vancomycin serum concentrations versus time over surgery to minimum inhibitory concentration ratio(AUCintra/MIC) of 400 (mg × h)/l and/or a target concentration of 15-20 mg/l. METHODS: In a prospective study, 40 patients divided into four subgroups (neonates, infants, children <10 years-old, ⩾10 years-old) undergoing cardiac surgery with cardiopulmonary bypass (CPB) were enrolled. A slow vancomycin bolus of 20 mg/kg, up to a maximum dose of 1000 mg was administered before skin incision and a further dose of 10 mg/kg (up to 500 mg) at CPB start. Vancomycin samples were collected intraoperatively at four time points. RESULTS: The median (interquartile range) age was 241.5 days (47-3898) and the median weight was 7.1 kg (3.1-37). The median AUCintra/MIC was 254.73 (165.89-508.06). In 11 patients the AUCintra/MIC target was not reached. Neonates displayed the lowest AUCintra/MIC values, and these were significantly lower than those of children ⩾10 years old (p = 0.02). Vancomycin concentrations were above the maximal target of 20 mg/l in 82.5% and 80% of patients at surgery and CPB start, respectively. At CPB and surgery end, 42.5% of patients showed vancomycin concentrations above 20 mg/l and 42.5% below 15 mg/l. Patients⩾10 years old showed the highest peak values whereas neonates were those with the lowest troughs. AUCintra/MIC correlated with age(r:0.36, p = 0.02), weight(r:0.35, p = 0.03), intraoperative protein value(r:0.40, p = 0.01), CPB priming volume/kg(r:-0.33, p = 0.04), CPB duration(r:0.36, p = 0.02) and vancomycin troughs(r:0.35, p = 0.04). CONCLUSIONS: An AUCintra/MIC ⩾400 target was not reached in one-quarter of children undergoing heart surgery. Vancomycin peaked before the start of surgery and neonates were those with the lowest troughs. Vancomycin concentrations are affected by CPB hemodilution and by patients' age and weight.

Vancomycin prophylaxis in paediatric patients following cardiac surgery: a retrospective evaluation of trough levels and associated variables.

OBJECTIVES: Therapeutic drug monitoring during vancomycin administration is recommended. However, little information is available in case of paediatric vancomycin prophylaxis. The aim of this study was to analyse vancomycin trough levels on postoperative day (POD) 2 and 3 after paediatric cardio-surgery to assess the clinical predictors and outcomes associated with vancomycin concentrations and to evaluate whether adjustments are effective to target optimal levels. METHODS: A retrospective study was conducted in paediatric patients receiving vancomycin prophylaxis after elective cardio-surgery. Adjustments were made if levels between 20 and 30 (halving subsequent dose) or ˃30 mg/l (dose withheld) were found. RESULTS: Vancomycin doses of the 100 examined children (3.7-6.4 years) were 12.8 (2.5), 9.4 (5.4) and 9.7 (4.5) mg/kg, on POD1, 2 and 3, respectively (P = 0.0001). The 200 vancomycin trough levels decreased from 16.9 (11.4) on POD2 to 14.6 (8.5) on POD3 (P = 0.003). Overall, 66 troughs were sub-target, 68 reached the optimal target and 66 were supra-target. On POD2 and 3, 32 and 27 dose adjustments were required, leading to a reduced number of patients with supra-target troughs. Neonates showed a higher number of supra-target levels with respect to non-neonatal patients on both POD2 (P = 0.003) and 3 (P = 0.0001). At multivariable regression analysis, vancomycin levels showed independent association with weight and creatinine levels on both POD2 and 3. Vancomycin levels correlated with ventilation days (P = 0.31, P = 0.039), but not with methicillin-resistant Staphylococcus aureus positivity (P = 0.69). CONCLUSIONS: Vancomycin prophylaxis in paediatric cardio-surgery requires strict therapeutic drug monitoring and several dosage adjustments. Supra-target troughs are frequent and neonatal age, weight and creatinine levels significantly affect vancomycin concentrations.

Population Pharmacokinetics of Cefoxitin Administered for Pediatric Cardiac Surgery Prophylaxis.

BACKGROUND: Available data about pharmacokinetics (PK) of antimicrobials administered as surgical prophylaxis to children undergoing cardiac surgery with cardiopulmonary bypass (CPB) showed that drug concentrations during CPB may be supra or subtherapeutic. The aim of this study was to determine the population PK and pharmacodynamic target attainment (PTA) of cefoxitin during pediatric CPB surgery. METHODS: A prospective interventional study was conducted. Cefoxitin (40 mg/kg, up to max 1000 mg) was administered before skin incision. Blood samples were obtained in the operatory room throughout surgery. Population PK, PTA, and safety of cefoxitin were evaluated in neonates, infants, children <10 and >10 years old. RESULTS: Forty patients were enrolled. Cefoxitin levels correlated with time from bolus administration (r = -0.6, P = 0.0001) and, after 240 minutes from bolus, drug values below the target (8 mg/L) were shown. Cefoxitin concentrations were best described by a one-compartment model with first order elimination. A significant relationship was identified between body weight, age, body mass index, and serum creatinine on drug clearance and age, body weight, and body mass index on cefoxitin volume of distribution. The PTA for free drug concentration being above the minimum inhibitory concentration of 8 mg/L for at least 240 minutes was >90% in all age groups except in patients >10 years of age (PTA = 62%). CONCLUSIONS: Cefoxitin PK appears to be significantly influenced by CPB with generally reduced drug clearance. The PTA was adequately achieved in the majority of patients except in patients >10 years old or longer surgeries.

Cefoxitin Prophylaxis During Pediatric Cardiac Surgery: Retrospective Exploration of Postoperative Trough Levels.

BACKGROUND: This study aimed to explore inter-individual variability of cefoxitin trough levels, predictors of serum cefoxitin concentration and the probability of target attainment of drug levels above 4 mg/L after pediatric cardiac surgery. METHODS: Retrospective study on children scheduled for elective cardiac surgery and having cefoxitin trough levels available up to 24 hours postsurgery. RESULTS: Overall, 68 children (9 neonates, 34 infants, 15 children below or equal to 10 years old and 10 patients above this age) were included. Of these, 16 surgeries were performed off cardiopulmonary bypass and 52 were performed on cardiopulmonary bypass. The free cefoxitin concentrations showed a median (interquartile range) concentration of 1.7 (0.6-4.2) mg/L. The range of cefoxitin concentrations showed a 150-fold and 340-fold variability at cardiac intensive care unit admission and after 24 hours, respectively. The pharmacodynamics (PD) targets of free cefoxitin at 100% of the dosing interval, considering Eucast breakpoints for Methicillin Sensitive Staphylococcus Aureus (4 mg/L) and E.Coli (8 mg/L), were obtained in 28% and 16% of patients, respectively. Patient weight (odds ratio, 0.7; 95% confidence interval, 0.62-0.92; P = 0.006) and serum creatinine concentrations (odds ratio, 25; 95% confidence interval, 18-36; P = 0.004) showed a significant relationship with the PD targets. CONCLUSIONS: Cefoxitin trough concentrations vary significantly in the first 24 hours after pediatric cardiac surgery. Both serum creatinine and body weight showed independent associations with cefoxitin concentration. The PD target was not obtained in the vast majority of the explored population, regardless of the target bacteria.

Endotoxin Activity in Neonates Undergoing Cardiac Surgery: Cohort Study.

BACKGROUND: Endotoxemia in pediatric cardiac surgical patients is poorly understood. The endotoxin activity assay (EAA) levels were examined in neonates undergoing cardiac surgery in order to assess their reference levels and their association with other pre-, intra-, and postoperative risk factors for gut hypoperfusion. We finally observed if refeeding was associated with modification of endotoxin levels. METHODS: In a prospective cohort study, neonates undergoing surgery for correction or palliation were enrolled. Preterm birth, weight below 1.5 kg, the need for extracorporeal membrane oxygenation, and urgent surgery were exclusion criteria. RESULTS: Among the 26 enrolled neonates, 12 underwent on-pump and 14 off-pump surgery, 22 received a preoperative infusion of prostaglandin E2. Overall, 11 patients were surgically corrected and 15 received a palliation. Endotoxin activity assay baseline levels were inversely correlated with age at surgery ( r = -.50, P = .006) and they increased to postoperative day2 ( P = .002). On-pump versus off-pump surgery ( P =.36) and surgical palliation with a Blalock-Taussig shunt versus correction ( P = .45) did not predict increase in EAA levels. Aortic clamping for coarctation repair was associated with the lowest levels ( P = .04). Systolic, mean, and diastolic pressures were associated with EAA levels ( r = -.55, P = .01; r = -.45, P = .02; r = -.37, P = .04, respectively). Endotoxin activity assay levels after refeeding were similar to baseline levels. Patients with abdominal distension and feeding intolerance showed higher median peak EAA levels (0.7, 0.66-1.11) than asymptomatic patients (0.53, 0.35-0.64; P = .01). CONCLUSIONS: Endotoxin activity assay levels increase after elective neonatal surgery and are not modified by refeeding. High postoperative levels may predict feeding intolerance.

Use of low-dose dexmedetomidine in combination with opioids and midazolam in pediatric cardiac surgical patients: randomized controlled trial.

BACKGROUND: Dexmedetomidine is a selective agonist of α2 receptors that induces hypnotic, sedative and mild analgesic effect. The aim of our study was to test the effects of dexmedetomidine in combination with opioids and benzodiazepines compared to benzodiazepine-opioids alone. METHODS: A randomized controlled trial was conducted. Patients (children >30 days and <24 months undergoing correction of complex congenital heart diseases [CHD]) were randomized to receive 0.5 mcg/kg/h dexmedetomidine in addition to half dose of opioids and benzodiazepines (D-CASES) or standard dose opioids and benzodiazepines (CONTROLs). PRIMARY OUTCOME: to compare the duration of mechanical ventilation (MV) in D-CASEs and CONTROLs. SECONDARY OUTCOMES: 1) the degree of sedation; 2) the onset of withdrawal symptoms; 3) the occurrence bradycardia and hypotension. RESULTS: Overall, 48 patients, 26 in CONTROLs group and 22 in D-CASEs group were ultimately included in the analysis after enrollment. The median duration of MV was 33.5 (16.7-75) hours in CONTROLs and 41.5 (23.7-71.2) hours in D-CASEs (P=0.51). Dexmedetomidine did not affect COMFORT and FLACC scales but it reduced the SOS scale in 15 D-CASEs vs. 11 CONTROLs (P=0.001). The incidence of bradycardia and hypotension and vasoactive support did not show significant differences in the two groups. CONCLUSIONS: Low dose of dexmedetomidine in combination with morphine and midazolam was safe in a high-risk cohort of CHD children after cardiac surgery and reduced the onset of withdrawal symptoms. However, it did not decrease MV time and the total amount of other sedative and analgesic drugs required in the post-operative period.