Mijeung Gwak

Acute kidney injury and renal regional oxygen saturation during aortic arch reconstruction in infants.

OBJECTIVE Acute kidney injury is a serious postoperative complication following cardiac surgery. The aortic arch repair technique using antegrade selective cerebral perfusion has been used, but it is unclear whether subdiaphragmatic organs such as the kidneys are perfused adequately. The authors compared intraoperative renal regional oxygen saturation using near-infrared spectroscopy between infants with and without postoperative acute kidney injury after undergoing aortic arch reconstruction. DESIGN Retrospective medical records review. SETTING University medical center. PARTICIPANTS Elective cardiac surgical infants. INTERVENTIONS The author reviewed the perioperative clinical records of infants who underwent aortic arch reconstruction surgery using antegrade selective cerebral perfusion. During the operation, prestenotic (right radial or right brachial artery) and poststenotic (femoral or umbilical artery) invasive arterial blood pressure and cerebral and renal regional oxygen saturation were monitored continuously. Development of acute kidney injury within 72 hours of surgery was investigated. RESULTS A total of 47 patients were enrolled in this study. Postoperative acute kidney injury occurred in 19 patients (40.4%). Intraoperative renal regional oxygen saturation was similar between patients with and without acute kidney injury. Intraoperative prestenotic and poststenotic mean arterial blood pressure and cerebral regional oxygen saturation also were similar between the 2 groups. CONCLUSIONS The intraoperative renal tissue oxygen saturation was not different between the groups with or without postoperative acute kidney injury in infants who underwent aortic arch repair using antegrade selective cerebral perfusion.

Usefulness of the maximum rate of pressure rise in the central and peripheral arteries after weaning from cardiopulmonary bypass in pediatric congenital heart surgery: A retrospective analysis

Abstract The maximum rate of pressure rise (dP/dtmax) in radial artery has been proposed as a noninvasive surrogate of aortic dp/dtmax, reflecting left ventricular (LV) contractility in children. The aim of this study was to investigate relationship between aortic and radial dp/dtmax at weaning from cardiopulmonary bypass (CPB) and usefulness of these indices for estimating postoperative outcomes in pediatric congenital heart surgery. Aortic and radial arterial pressure waveforms were analyzed simultaneously during weaning from CPB in 29 congenital heart surgery. The maximum first derivatives of aortic and radial arterial waveforms were calculated and averaged from 3 consecutive respiratory cycles. We obtained the maximum vasoactive inotropic score during the first 36 postoperative hours, LV ejection fraction, and fractional shortening on transthoracic echocardiography performed within postoperative day 7. A significant difference between aortic and radial dP/dtmax was observed (mean difference 356 mm Hg/s, 44% of averages), and radial dP/dtmax was weakly correlated with aortic dP/dtmax (r =0.373, P = 0.047). Aortic dP/dtmax was significantly associated with the maximum vasoactive inotropic score (P < 0.001), postoperative LV ejection fraction (P = 0.018), and fractional shortening (P = 0.015); however, radial dP/dtmax was not. On Receiver operating characteristic analysis, aortic dP/dtmax had a greater area under the curve than radial dP/dtmax in predicting higher vasoactive inotropic score (0.827 vs 0.673). Immediately after CPB in pediatric congenital heart surgery, radial dP/dtmax may not replace aortic dP/dtmax because of a discrepancy between central and peripheral arterial waveforms. In this critical period, aortic dP/dtmax can be useful to estimate postoperative ventricular function rather than peripherally derived dP/dtmax.

Effects of the Trendelenburg Position and Positive End-Expiratory Pressure on the Internal Jugular Vein Cross-Sectional Area in Children With Simple Congenital Heart Defects.

AbstractCatheterization of the internal jugular vein (IJV) remains difficult in pediatric populations. Increasing the cross-sectional area (CSA) of the IJV facilitates cannulation and decreases complications. We aimed to evaluate the Trendelenburg position and the levels of positive end-expiratory pressure (PEEP) at which the maximum increase of CSA of the IJV occurred in children undergoing cardiac surgery.In this prospective study, the CSA of the right IJV was assessed using ultrasound in 47 anesthetized pediatric patients with simple congenital heart defects. The baseline CSA was obtained in response to a supine position with no PEEP and compared with 5 different randomly ordered maneuvers, that is, a PEEP of 5 and 10 cm H2O in a supine position and of 0, 5, and 10 cm H2O in a 10° Trendelenburg position. Hemodynamic variables, including blood pressure and heart rate, maximum and minimum diameters, and CSA, were measured.All maneuvers increased the CSA of the right IJV with respect to the control condition. In the supine position, the CSA was increased by 9.4% with a PEEP of 5 and by 19.5% with a PEEP of 10 cm H2O. The Trendelenburg tilt alone increased the CSA by 19.0%, and combining the 10° Trendelenburg with a 10 cm H2O PEEP resulted in the largest IJV CSA increase (33.3%) compared with the supine position with no PEEP. Meanwhile, vital signs remained relatively steady during the experiment.The application of the Trendelenburg position and a 10 cm H2O PEEP thus significantly increases the CSA of the right IJV, perhaps improving the chances of successful cannulation in pediatric patients with simple congenital heart defects.

Hemolysis of irradiated leukoreduced red blood cells during rapid warming: An in vitro experimental study

Background Although water chambers are often used as surrogate blood-warming devices to facilitate rapid warming of red blood cells (RBCs), these cells may be damaged if overheated. Moreover, filtered and irradiated RBCs may be damaged during the warming process, resulting in excessive hemolysis and extracellular potassium release. Methods Using hand-held syringes, each unit of irradiated and leukocyte-filtered RBCs was rapidly passed through a water chamber set to different temperatures (baseline before blood warming, 50℃, 60℃, and 70℃). The resulting plasma potassium and free hemoglobin levels were then measured. Results Warming RBCs to 60℃ and 70℃ induced significant increases in free hemoglobin (median [interquartile ranges] = 60.5 mg/dl [34.9–101.4] and 570.2 mg/dl [115.6–2289.7], respectively). Potassium levels after warming to 70℃ (31.4 ± 7.6 mEq/L) were significantly higher compared with baseline (29.7 ± 7.1 mEq/L; P = 0.029). Potassium levels were significantly correlated with storage duration after warming to 50℃ and 60℃ (r = 0.450 and P = 0.001; r = 0.351 and P = 0.015, respectively). Conclusions Rapid warming of irradiated leukoreduced RBCs to 50℃ may not further increase the extracellular release of hemoglobin or potassium. However, irradiated leukoreduced RBCs that have been in storage for long periods of time and contain higher levels of potassium should be infused with caution.

Ultrasound-guided evaluation of the bifurcation of the femoral artery and vein in pediatric patients

BACKGROUND The femoral arteries (FA) and femoral veins (FV) are useful access sites for diagnostic and interventional procedures. In adults, the usual puncture sites are 1-3 cm distal from the inguinal crease. In children, however, the optimal puncture site vessels are not known. The aim of our study was to assess the number of branches and bifurcation sites of the femoral vessels in children by using ultrasonography. METHODS Color Doppler ultrasonography was used to determine bifurcation sites of the FA and FV, relative to the inguinal crease, in 48 children (median age, 4 yr; median weight, 18.7 kg) with American Society of Anesthesiologists (ASA) Physical Status (PS) score 1-2 and who were scheduled for general anesthesia. RESULTS The numbers of FAs and FVs at the inguinal crease were 1.83 +/- 0.39 and 1.08 +/- 0.29, respectively, in infants, and 1.83 +/- 0.58 and 1.0 +/- 0.0, respectively, in 10-year-old children. The bifurcation site of the FA in infants and those aged 10 years was 0.78 +/- 0.30 cm and 1.47 +/- 0.27 cm proximal to the inguinal crease, respectively (P < 0.05), whereas the bifurcation site of the FV in these two age groups was -0.96 +/- 0.27 cm and -2.29 +/- 1.09 cm distal to the inguinal crease, respectively (P < 0.05). CONCLUSIONS In children, the FA frequently bifurcates proximal to the inguinal crease, whereas the FV bifurcates distal to the inguinal crease. However, there are anatomical differences among age groups, so care should be taken to avoid complications during femoral vessel cannulation.