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.

Mechanical Power during Veno-Venous Extracorporeal Membrane Oxygenation Initiation: A Pilot-Study.

Mechanical power (MP) represents a useful parameter to describe and quantify the forces applied to the lungs during mechanical ventilation (MV). In this multi-center, prospective, observational study, we analyzed MP variations following MV adjustments after veno-venous extra-corporeal membrane oxygenation (VV ECMO) initiation. We also investigated whether the MV parameters (including MP) in the early phases of VV ECMO run may be related to the intensive care unit (ICU) mortality. Thirty-five patients with severe acute respiratory distress syndrome were prospectively enrolled and analyzed. After VV ECMO initiation, we observed a significant decrease in median MP (32.4 vs. 8.2 J/min, p < 0.001), plateau pressure (27 vs. 21 cmH2O, p = 0.012), driving pressure (11 vs. 8 cmH2O, p = 0.014), respiratory rate (RR, 22 vs. 14 breaths/min, p < 0.001), and tidal volume adjusted to patient ideal body weight (VT/IBW, 5.5 vs. 4.0 mL/kg, p = 0.001) values. During the early phase of ECMO run, RR (17 vs. 13 breaths/min, p = 0.003) was significantly higher, while positive end-expiratory pressure (10 vs. 14 cmH2O, p = 0.048) and VT/IBW (3.0 vs. 4.0 mL/kg, p = 0.028) were lower in ICU non-survivors, when compared to the survivors. The observed decrease in MP after ECMO initiation did not influence ICU outcome. Waiting for large studies assessing the role of these parameters in VV ECMO patients, RR and MP monitoring should not be underrated during ECMO.

Clinical and Operative Determinants of Acute Kidney Injury after Cardiac Surgery.

INTRODUCTION: Cardiac surgery-associated acute kidney injury (CSA-AKI) is associated with increased morbidity and mortality. OBJECTIVES: We aimed to identify potentially modifiable risk factors for CSA-AKI. METHODS: This was asingle-center retrospective cohort study of 495 adult patients undergoing cardiac surgery. AKI was diagnosed and staged using full KDIGO criteria incorporating baseline serum creatinine (SC) levels and correction of postoperative SC levels for fluid balance. We examined the association of routinely available clinical and laboratory data with AKI using multivariate logistic regression modeling. RESULTS: A total of 103 (20.8%) patients developed AKI: 16 (15.5%) patients were diagnosed with AKI upon hospital admission, and 87 (84.5%) patients were diagnosed with CSA-AKI. Correction of SC levels for fluid balance increased the number of AKI cases to 104 (21.0%), with 6 patients categorized to different AKI stages. Univariate logistic regression analysis identified five preoperative (age, sex, diabetes mellitus, preoperative systolic pulmonary arterial pressure [PSPAP], acute decompensated heart failure) and five intraoperative predictors of AKI (age, sex, red blood cell [RBC] volume transfused, use of minimally invasive surgery, duration of cardiopulmonary bypass). When all preoperative and intraoperative variables were incorporated into one model, six predictors remained significant (age, sex, use of minimally invasive surgery, RBC volume transfused, PSPAP, duration of cardiopulmonary bypass). Model discrimination performance showed an area under the curve of 0.69 for the model including only preoperative variables, 0.76 for the model including only intraoperative variables, and 0.77 for the model including all preoperative and intraoperative variables. CONCLUSIONS: Use of minimally invasive surgery and therapies mitigating PSPAP and intraoperative blood loss may offer protection against CSA-AKI.