Neutrophil gelatinase-associated lipocalin as an early indicator of acute kidney injury
following pediatric cardiac surgery
Yoshihito Wakamatsu (Department of Clinical Engineering, Juntendo University, School ofMedicine) ，Keisuke Nakanishi，Satoshi Matsushita，Go Sato，Hideaki Yasumoto，Shiori
Kawasaki，Atsushi Amano
Abstract
Early intervention can significantly improve patient outcomes in acute kidney injury（AKI）.
In children with underdeveloped kidneys, it takes longer than 24 hours for serum creatinine（sCr）to peak after AKI onset. Furthermore, even very subtle increases in sCr are associatedwith poor outcomes, making it more difficult to diagnose early AKI in pediatric cases. Theurinary neutrophil gelatinase-associated lipocalin（NGAL）levels of 64 patients undergoing
pediatric cardiac surgery using cardiopulmonary bypass from June 2018 to February 2019were measured to evaluate NGAL as an accurate indicator of postoperative AKI. Sixteen
patients（25%）developed AKI. The AKI group showed significantly higher Risk Adjustment
in Congenital Heart Surgery（RACHS-1）scores（p＝0.028） and a significantly longer
operative time（p＝0.048）, cardiopulmonary bypass time （p＝0.048）, and ventilator usetime（p＜0.001）than the non-AKI group. After surgery, urinary NGAL was significantly
higher in the AKI group with a median of 37.1ng/mL（11.1-148.3）against 5.6ng/mL（1.035.8）of the non-AKI group（p＝0.021）. Using a cut-off value of 11.9ng/mL, the area under
the curve of urinary NGAL for predicting AKI was 0.69, the sensitivity was 75%, and thespecificity was 44 %. Higher RACHS-1 scores are associated with postoperative AKI. Urinary
NGAL shows a moderate correlation with AKI diagnosis, and may be useful for predicting
AKI early in the perioperative period.
Key words
neutrophil gelatinase-associated lipocalin（NGAL），acute kidney injury（AKI），pediatriccardiac surgery， cardiopulmonary bypass，The Risk Adjustment in Congenital Heart Surgery（RACHS-1）system

Impact of the tip design of the femoral arterial cannula on distal leg perfusion in minimallyinvasive cardiac surgery
Kohei Nagashima (Department of Clinical, Engineering Toranomon Hospital) ， Yuko
Matsusaka，Natsuki Hajikano，Nao Kozaki，Yuichi Takahashi，Eiichi Geshi，Minoru TabataAbstract［Objective］In minimally invasive cardiac surgery（MICS）, leg ischemia is one of the known
complications due to the femoral arterial cannulation. We routinely monitor distal leg
perfusion based on the regional oxygen saturation （ rSO2 ） using the near-infrared
spectroscopy（NIRS）for the prevention of lower limb ischemia. In this study, we examined
the impact of the tip design of the femoral arterial cannula on distal leg perfusion.
［ Methods ］ From April 2014 to September 2017, we performed 106 cases of rightthoracotomy MICS with femoral arterial cannulation. We used a cannula with multiple side
holes and no wire-reinforced tip in 52 patients（group C）, and a cannula with few side holes
and wire-reinforcement in 54 patients（group N）. We adjusted for confounding variables
using propensity score matching.
［Results］The rate of drops in rSO2 value greater than 25% was significantly lower in group
N than in group C（15.6% vs 60.0%；p＝0.003）. No significant difference was observed inother factors.
［Conclusion］In addition to conventional prevention methods, using a wire-reinforced
femoral arterial cannula may reduce the risk of lower limb ischemia in MICS.
Key words
minimally invasive cardiac surgery （ MICS ）， tip design of the cannula ， near-infrared
spectroscopy（NIRS）， lower limb ischemia

Investigation of index of optimal perfusion using oxygen delivery and venous oxygen
saturation in cardiopulmonary bypass -- A two-center observational study Hiroshi Mukaida (Department of Clinical Engineering, Juntendo University Hospital) ，Satoshi Matsushita，Kohei Nagashima，MinoruTabata，Atsushi Amano
Abstract
Venous oxygen saturation（SvO2）poorly reflects regional oxygen supply-demand imbalance
which suggests its limitations as an indicator of adequate perfusion during cardiopulmonary
bypass（CPB）. Recently, the role of oxygen delivery （DO2）in CPB has gained attention
since studies have shown that maintaining sufficient DO2 is associated with reduced incidenceof postoperative acute kidney injury（AKI）. In this study, we investigated the relationshipbetween AKI onset, SvO2 and DO2, and examined whether the limitations of SvO2 could becompensated by monitoring DO2. We enrolled adult patients（estimated glomerular filtration
rate ＞ 60mL/min/1.73m2 ） who underwent open heart surgery using CPB at Juntendo
University Hospital and Tokyo Bay Urayasu Ichikawa Medical Center between March 2017and December 2018. Postoperative AKI was used as an index of optimal perfusion. The area
under the curve（AUC＜SvO275, AUC＜DO2i300）and cumulative time（Time＜SvO275, Time＜DO2i300）below the cutoff threshold were calculated. Wilcoxon test, Chi-square test, andreceiver operating characteristic（ROC）analysis were used to evaluate the relationshipbetween intraoperative variables and postoperative AKI. Patients were stratified into AKI（n＝191）and non-AKI groups（n＝49）. The AKI group had a larger AUC＜DO2i300（450 vs1103；p＝0.025）and a longer Time＜DO2i300（7.3 vs 16.3min；p＝0.016）, but AUC＜SvO2（42 vs 30；p＝0.620）and Time＜SvO275（2.7 vs 3.7min；p＝0.771）were not significantly

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different between the groups. The ROC analysis for AKI incidence showed significant
difference between AUC values for Time＜SvO275 and Time＜DO2i300（0.098, p＝0.028）. In
both groups, SvO2 was generally maintained at the usual safe range of 75% or more. However,DO2i was significantly lower in the AKI group, suggesting that maintaining SvO2 above 75%
does not prevent postoperative AKI. Maintaining DO2i levels＞300mL/min/m2, in addition
to the standard SvO2 monitoring, as target for blood flow management can help ensure
optimal perfusion during CPB.
Key words
acute kidney injur，goal-directed perfusion，oxygen supply-demand balance，cardiopulmonary
bypass，cardiopulmonary bypass management

Study on influencing factors on heparin reactivity
Tomoaki Yamashiro (Department of Clinical Engineering Management, Fujita Health
University Hospital) ，Makoto Hibiya，Kotone Kojima，Kota Shimizu，Takuya Fujiura，
Ryo Takeuchi，Yasushi Takagi
Abstract
Recently, it is recommended to keep activated clotting time（ACT）more than 480 seconds
during cardiopulmonary bypass（CPB）according to the guideline of American Society ofExtraCorporeal Technology（AmSECT）. However, it is not rare than ACT does not exceed
480 seconds after administration of unfractionated heparin（UFH）. We retrospectively
investigated parameters which influenced heparin reactivity in 137 patients out of 272
patients who underwent cardiovascular surgery with CPB from May 2017 to December 2018.
One hundred thirty-five patients were excluded to remove influences of initial UFH dose.
Heparin reactivity decrease was recognized in 41（30％）patients. Between patients withdecreased heparin reactivity（Low group）and others（Hi group）, there were significant
differences in age, aortic regurgitation（AR）, Hb, TP, ALB/TP, preoperative ACT（PreACT）,
total UFH dose, and antithrombin（AT）dose. In multivariate analysis, Alb and PreACT wereidentified as independent parameters influencing decreased heparin reactivity. The
evaluation of the suitability of parameters obtained from ROC curve suggested decreased
heparin reactivity might be observed when the albumin concentration is 3.8g/dL（cutoff value）
or less.
Key words
activated clotting time，unfractionated heparin，heparin reactivity

Experimental study of air intake during A-V MUF and confirmation of the bubble retention
capacity of an oxygenator
Daisuke Nagamine (Department of Clinical Engineering Center, Toyama UniversityHospital) ，Kenji Shimaoka，Mitsuru Tsunomori，Kuniaki Sato，Naoki Yoshimura
AbstractDuring the Modified Ultrafiltration（MUF）, negative pressure may arise in the oxygenatorand air may be sent into the patient. Therefore, we added a flow path with a check valve tothe conventional A-V MUF flow path. An experimental study was conducted on the effect ofA-V MUF efficiency and measures to prevent air intake from the oxygenator. Theseexperiments on the impact of reduced A-V MUF efficiency due to the addition of a checkvalve showed no significant impact. An experimental measures to prevent air intake from theoxygenator is although all the pressures became negative, the flow rate of the check valve did
not differ much from that of the MUF pump. On the other hands but there was a differencein the time for drawing air due to fluctuations in the MUF pump flow rate. With additional
experiments, we found that we could adjust the oxygenator so that it could retain air inside it.
Until the air is drawn into the secondary side of the oxygenator air could be retained inside
the oxygenator by the surface tension arised in the arterial filter pores. The self-vent
technology can remove air from hollow fiber and prevent misfeeding of air. The use of an
oxygenator with a check valve and bubble retention function can enhance the safety of MUF.
Key words
Modified ultrafiltration ， safety measures ， check valve ， surface tension ， self-venting
technology

Association between chloride dose during cardiopulmonary bypass management andpostoperative acute kidney injury
Satoshi Yoshida (Department of Clinical Engineering, Kyoto Prefectural University ofMedicine) ，Satoshi Numata，Sachiko Yamazaki，Keiichi Itatani，Yuya Hatanaka，YoshifumiYagi，Satoshi Teramukai，Hitoshi Yaku
Abstract［Objective］Acute kidney injury（AKI）is one of the postoperative complications of cardiac
surgery with cardiopulmonary bypass（CPB）. It has been reported that the incidence of AKI
is as high as 15-30％ and the prognosis is poor.
Chloride（Cl）is a type of electrolyte. Animal studies have shown that Cl itself causes renal
vasoconstriction and decreases glomerular filtration rate. However, there are no reports
showing the association between Cl dose during CPB management and postoperative AKI.
In this retrospective study, the total Cl dose during CPB management was defined as the totalCl dose from the CPB priming solution, the infusion and blood products used during CPB.
The objective of this study was to determine the association between the total Cl dose during
CPB management and postoperative AKI.
［Methods］The subjects were 301 patients aged 18 years or older who underwent open-heart
surgery with cardiac arrest by aortic cross-clamping and CPB from January 1, 2016 toDecember 31, 2018. A multivariate logistic regression analysis was performed to evaluate theassociation between the total Cl dose during CPB management and postoperative AKI.
Confounding factors, which were preselected based on the previous literature reports,
included age, sex, preoperative weight, estimated glomerular filtration rate, perfusionpressure during CPB management, the lowest oxygen delivery index during CPB
management, and CPB duration.
［ Results ］ The cutoff value of 18.0 g was obtained for the total Cl dose during CPB
management. In the multivariate logistic regression analysis using the cutoff value of 18.0 g,
the incidence of postoperative AKI was significantly higher in the category of the total Cl dose
＞18.0 g compared to the category ≤18.0 g（odds ratio: 2.376, P＝0.037）, suggesting thatthe total Cl dose ＞18.0 g is a statistically significant risk factor for postoperative AKI.
［Conclusion］In terms of the total Cl dose from the CPB priming solution, the infusion andblood products used during CPB, patients managed with the total Cl dose ＞18.0 g had ahigher incidence of postoperative AKI compared to those managed with the total Cl dose
≤18.0 g.
Key words
cardiopulmonary bypass（CPB），cardiopulmonary bypass management（CPB management），

acute kidney injury（AKI），chloride（Cl）