Pre‐operative anaemia,intra‐operative hepcidin concentration and acute kidney injury after cardiac surgery: a retrospective observational study

Acute kidney after cardiac surgery is more common in anaemic patients, whereas haemolysis during cardiopulmonary bypass may lead to iron‐induced renal injury. Hepcidin promotes iron sequestration by macrophages: hepcidin concentration is reduced by anaemia and increased by inflammation. We analysed the associations in 525 patients between pre‐operative anaemia (haemoglobin < 130 g.l^?1 in men and < 120 g.l^?1 in women), intra‐operative hepcidin concentration and acute kidney injury (dialysis or > 26.4 μmol.l^?1 or > 50% creatinine increase during the first two days after cardiac surgery. Rates of pre‐operative anaemia and postoperative kidney injury were 109/525 (21%) and 36/525 (7%), respectively. The median (IQR [range]) intra‐operative hepcidin concentration was 20 (10–33 [0–125]) μg.l^?1 and was lower in anaemic patients than those who were not: 15 (4–28 [0–125]) μg.l^?1 vs. 21 (12–33 [0–125]) μg.l^?1, respectively, p = 0.002. Four variables were independently associated with postoperative kidney injury, for which the beta‐coefficients (SE) were: minutes on cardiopulmonary bypass, 0.016 (0.004), p < 0.001; intra‐operative hepcidin concentration, 0.032 (0.008), p < 0.001; pre‐operative anaemia, 1.97 (0.56), p < 0.001; and Cleveland clinic risk score, 0.88 (0.35), p = 0.005. Contrary to generally increased rates of kidney injury in patients with higher hepcidin concentrations, rates of kidney injury in anaemic patients were lower in patients with higher hepcidin concentrations, beta‐coefficient (SE) ?0.037 (0.01), p = 0.007. In cardiac surgical patients the rate of postoperative acute kidney injury predicted by the Cleveland risk score might be adjusted for pre‐operative anaemia and intra‐operative cardiopulmonary bypass time and hepcidin concentration. Pre‐operative correction of anaemia, reduction in intra‐operative bypass time and modification of iron homeostasis and hepcidin concentration might reduce acute kidney injury.     

The effect of 6% hydroxyethyl starch (130/0.4) on acute kidney injury in paediatric cardiac surgery: a prospective,randomised trial

We have evaluated the effect of a colloid solution on acute kidney injury in paediatric cardiac surgery. A total of 195 patients were ramdomly divided into an hydroxyethyl starch group and a control group. In the starch group, 6% hydroxyethyl starch 130/0.4 (Volulyte^®) was used as the primary fluid for volume resuscitation but was limited to 30 ml.kg^?1. In the control group, only crystalloid fluid was used during the peri‐operative period. The incidence of acute kidney injury, peri‐operative transfusion, clinical outcomes and laboratory data were compared. The incidence of acute kidney injury determined by Paediatric Risk, Injury, Failure, Loss, End‐stage renal disease (pRIFLE) and Acute Kidney Injury Network (AKIN) criteria were no different between the two groups (starch group 40.8% vs. control group 30.0%; p = 0.150 using pRIFLE; 19.6% vs. 21.1% respectively, p = 0.602 using AKIN). There were no differences in clinical outcomes such as mortality, major adverse events, intensive care unit stay or duration of mechanical ventilation. Clotting time as measured using rotational thromboelastometry (ROTEM) was prolonged, and clot firmness after 10 min and maximal clot firmness were shorter in the starch group compared with the control group after sternal closure. There was no difference in transfusion between the two groups. Patients with acute kidney injury had worse clinical courses than those without acute kidney injury. We conclude that intra‐operative use of 6% hydroxyethyl starch 130/0.4 up to 30 ml.kg^?1 was not associated with postoperative acute kidney injury in paediatric cardiac patients.     

Effect of dexamethasone on perioperative renal function impairment during cardiac surgery with cardiopulmonary bypass

Background. In cardiac surgery with cardiopulmonary bypass (CPB),corticosteroids are administered to attenuate the physiologicalchanges caused by the systemic inflammatory response. The effectsof corticosteroids on CPB-associated renal damage have not beendocumented. The purpose of this study was to evaluate the effectsof dexamethasone on perioperative renal dysfunction in patientsundergoing cardiac surgery with CPB. Methods. Renal damage was prospectively studied in 20 patientswithout concomitant morbidity undergoing coronary artery surgerywith CPB. Patients were randomized in a double-blind fashionto receive dexamethasone or placebo. Markers of glomerular function(creatinine clearance) and damage (microalbuminuria), and markersof tubular function (fractional excretion of sodium and freewater clearance) and damage (N-acetyl-ß-D glucosaminidase(NAG)) were evaluated in addition to plasma and urinary glucoselevels. Plasma and urinary specimens were obtained at the followingtime periods: (1) baseline, during the 12 h before surgery;(2) skin incision before heparinization; (3) from heparinizationuntil the end of CPB; (4) during the 2 h following weaning fromCPB; (5) in the intensive care unit from 2 to 6 h after weaningof CBP; (6) and from 36 to 60 h after weaning of CPB. Results. CPB was associated with an increase in markers in theplacebo group, which returned to baseline during the secondpostoperative day, demonstrating a transient impairment of glomerularand tubular renal function. Similar patterns were observed inpatients treated with dexamethasone. While postoperative glycosuriawas significantly higher in the dexamethasone-treated group,no other differences between groups were observed. Conclusion. Dexamethasone administration before CPB has no protectiveeffect on perioperative renal dysfunction in low-risk cardiacsurgical patients.     

Postoperative microcirculatory perfusion and endothelial glycocalyx shedding following cardiac surgery with cardiopulmonary bypass

We investigated microcirculatory perfusion disturbances following cardiopulmonary bypass in the early postoperative period and whether the course of these disturbances mirrored restoration of endothelial glycocalyx integrity. We performed sublingual sidestream dark field imaging of the microcirculation during the first three postoperative days in patients who had undergone on-pump coronary artery bypass graft surgery. We calculated the perfused vessel density, proportion of perfused vessels and perfused boundary region. Plasma was obtained to measure heparan sulphate and syndecan-1 levels as glycocalyx shedding markers. We recruited 17 patients; the mean (SD) duration of non-pulsatile cardiopulmonary bypass was 103 (18) min, following which 491 (29) ml autologous blood was transfused through cell salvage. Cardiopulmonary bypass immediately decreased both microcirculatory perfused vessel density; 11 (3) vs. 16 (4) mm.mm⁻², p = 0.052 and the proportion of perfused vessels; 92 (5) vs. 69 (9) %, p < 0.0001. The proportion of perfused vessels did not increase after transfusion of autologous salvaged blood following cardiopulmonary bypass; 72 (7) %, p = 0.19 or during the first three postoperative days; 71 (5) %, p < 0.0001. The perfused boundary region increased after cardiopulmonary bypass; 2.2 (0.3) vs. 1.9 (0.3) μm, p = 0.037 and during the first three postoperative days; 2.4 (0.3) vs. 1.9 (0.3) μm, p = 0.003. Increased plasma heparan sulphate levels were inversely associated with the proportion of perfused vessels during cardiopulmonary bypass; R = −0.49, p = 0.02. Plasma syndecan-1 levels were inversely associated with the proportion of perfused vessels during the entire study period; R = −0.51, p < 0.0001. Our study shows that cardiopulmonary bypass-induced acute microcirculatory perfusion disturbances persist in the first three postoperative days, and are associated with prolonged endothelial glycocalyx shedding. This suggests prolonged impairment and delayed recovery of both microcirculatory perfusion and function after on-pump cardiac surgery.     

Fenoldopam infusion for renal protection in high-risk cardiac surgery patients: a randomized clinical study

OBJECTIVE: The purpose of this study was to evaluate the renoprotective effects of fenoldopam in patients at high risk of postoperative acute kidney injury undergoing elective cardiac surgery requiring cardiopulmonary bypass. DESIGN: A double-blind randomized clinical trial. Setting: Hospital. Participants: One hundred ninety-three patients. Interventions: Patients undergoing cardiac surgery were randomly assigned to receive a continuous infusion of fenoldopam, 0.1 microg/kg/min (95 patients), or placebo (98 patients) for 24 hours. Patients were included if at least 1 of the following risk factors was present: preoperative serum creatinine > or =1.5 mg/dL, age >70 years, diabetes mellitus, or prior cardiac surgery. Serum creatinine and urinary output were measured at baseline (T1), 24 hours (T2), and 48 hours after surgery (T3). Acute kidney injury was defined as a postoperative serum creatinine level of > or =2 mg/dL with an increase in serum creatinine level of 0.7 mg/dL or greater from preoperative to maximum postoperative values. MEASUREMENTS AND MAIN RESULTS: Acute kidney injury developed in 12 of 95 (12.6%) patients receiving fenoldopam and in 27 of 98 (27.6%) patients receiving placebo (p = 0.02), whereas renal replacement therapy was started in 0 of 95 and 8 of 98 (8.2%) patients, respectively (p = 0.004). Serum creatinine was similar at baseline (1.8 +/- 0.4 mg/dL v 1.9 +/- 0.3 mg/dL) in the fenoldopam and placebo groups but differed significantly (p < 0.001 and p < 0.001) 24 hours (1.6 +/- 0.2 mg/dL v 2.5 +/- 0.6 mg/dL) and 48 hours (1.5 +/- 0.3 mg/dL v 2.8 +/- 0.4 mg/dL) after the operation. CONCLUSIONS: A 24-hour infusion of 0.1 mug/kg/min of fenoldopam prevented acute kidney injury in a high-risk population undergoing cardiac surgery.     

A pilot goal-directed perfusion initiative is associated with less acute kidney injury after cardiac surgery

Background

We sought to determine whether a pilot goal-directed perfusion initiative could reduce the incidence of acute kidney injury after cardiac surgery.

Hemodynamic effects of dobutamine and dopexamine after cardiopulmonary bypass in pediatric cardiac surgery*

Background: After surgical repair of congenital heart disease, inotropic support is sometimes necessary to wean from cardiopulmonary bypass. In pediatric cardiac surgery, dobutamine and dopamine are often used as inotropic support. Dopexamine is a synthetic catecholamine, which has positive inotropic and vasodilating properties. Because the hemodynamic effects of catecholamines are modified after cardiopulmonary bypass, the aim of this study was to investigate the effects of dobutamine and dopexamine on cardiac index and systemic vascular resistance index after cardiopulmonary bypass in pediatric cardiac surgery. Methods: The study was performed in a prospective, randomized, and double‐blinded cross‐over design. The investigation included 11 children for elective, noncomplex congenital heart surgery. After weaning from cardiopulmonary bypass and a 20‐min period of steady state, children received either 2.5 μg·kg^?1·min^?1 dobutamine or 1 μg·kg^?1·min^?1 dopexamine for 20 min. Cardiac index (transpulmonary thermodilution), mean arterial pressure, central venous pressure, stroke volume, systemic vascular resistance, and central venous oxygen saturation were determined. The primary outcome variable was cardiac index. Results: No difference in cardiac index was observed between the two groups (P = 0.594). Both drugs increased cardiac index, dopexamine from 3.9 ± 0.6 to 4.7 ± 0.8 l·min^?1·m^?2 (P = 0.003) and dobutamine from 4.1 ± 0.7 to 4.8 ± 0.7 l·min^?1·m^?2 (P = 0.004). During treatment with dobutamine, children presented with significantly higher mean arterial pressure (P = 0.003) and systemic vascular resistance index (P = 0.026). Conclusions: This trial demonstrates that low‐dose dobutamine and dopexamine both increase cardiac index during pediatric cardiac surgery but with different hemodynamic effects.     

Evaluation of serum cysteine-rich protein 61 and cystatin C levels for assessment of acute kidney injury after cardiac surgery

Objective The occurrence of acute kidney injury (AKI) after cardiopulmonary bypass (CPB) can lead to morbidity and mortality. We hypothesized that cysteine-rich protein 61 (CYR61) and cystatin C (CysC) may be potential novel biomarkers of AKI after cardiopulmonary bypass. Methods Patients were classified into AKI and non-AKI group depending on serum creatinine. Levels of creatinine, CysC, and CYR61 were measured at five time-points before and within 48?h after the surgery. Results Fifty patients were included in the study. Serum creatinine pre-operative values were 74.0?±?43.3?μmol/L in AKI group vs. 64.8?±?17.9?μmol/L in non-AKI group. During 48?h, the values increased to 124.6?±?67.2?μmol/L in AKI group (p?<?0.001) but in non-AKI group they did not change significantly. Serum CysC values were significantly increased already 2?h after CBP in AKI group (949?±?557?μg/L, p?<?0.05) compared to non-AKI group (700?±?170?μg/L). Pre-operative serum CYR61 tended to be lower in AKI group (12.4?μg/L) than in non-AKI group (20.3?μg/L), but 24?h after the surgery, the levels in AKI group tended to be higher than non-AKI group. Conclusion Serum CYR61 does not seem to be an early predictor of AKI in patients after cardiac surgery with CPB, but it might possibly identify patients at risk of developing more severe kidney injury. Serum CysC could be a promising biomarker of AKI, differentiating patients at risk of developing AKI after cardiac surgery as early as 2?h after surgery.     

The effects of pulsatile and non-pulsatile cardiopulmonary bypass on renal blood flow and function

The physiologic effects of pulsatile and non-pulsatile flow in cardiopulmonary bypass were compared in terms of the relationship between different flow rates and what effects these had on pulsatile and non-pulsatile flow. Forty adult mongrel dogs were used in this study and divided into 5 groups, each comprised of 8 animals, according to the flow rate during cardiopulmonary bypass, namely; 40, 60, 80, 100, or 120 ml/kg/min. The animals were perfused with either pulsatile or non-pulsatile flow for 1 hour, given randomly at the same mean flow rate. At flow rates of 80 and 100 ml/kg/min, the mean arterial blood pressure and total peripheral vascular resistance were significantly lower in pulsatile flow than in non-pulsatile flow, and the renal blood flow was significantly greater in pulsatile flow than in non-pulsatile flow. The renal arterial-venous lactate difference was significantly less in pulsatile flow than in non-pulsatile flow at a flow rate of 80 ml/kg/min, and the renal lactate extraction was significantly higher in pulsatile flow than in non-pulsatile flow at the same flow rate. The renal excess lactate was significantly lower in pulsatile flow than in non-pulsatile flow at a flow rate of 100 ml/kg/min. There were no significant differences in these parameters between the two types of perfusion at flow rates of 40, 60 or 120 ml/kg/min. Pulsatile flow was therefore apparently advantageous, when compared to non-pulsatile flow, in terms of hemodynamics, renal circulation, and metabolism of the kidney at flow rates of 80 and 100 ml/kg/min. However, when the flow rate was 120 ml/kg/min, pulsatile flow and non-pulsatile flow had the same effects.     

The effects of cardiac surgery on early and late pulmonary functions

Background: Impaired pulmonary functions are common in cardiac patients. Early and late effects of cardiac surgery on pulmonary function tests (PFTs) are presented.
Methods: Fifty patients undergoing cardiac surgery (coronary artery bypass grafting [CABG, 74%], valve replacement or val-vuloplasty [20%] and combined procedures [6%]) were studied. Anginal and cardiac failure symptoms severity, and smoking history, were evaluated preoperatively. PETS were studied and compared pre-, and 3 weeks and 3.5 months postoperatively.
Results: Pre- and postoperative PFTs were inversely related to severity of preoperative symptoms. Forced vital capacity (FVC) dropped from 98% of predicted preoperatively, to 63% ( P < 0.00001) and 75% ( P < 0.0001) 3 weeks and 3.5 months postoperatively, respectively. Expiratory volume in the first 1 s of forced expiration (FEW.O) decreased from 95% to 61% ( P < 0.00001) and 70% ( P < 0.00001), respectively. Forced expiratory flow at 50% of vital capacity (FEF50) decreased from 85% to 56% ( P < 0.00001) and 59% ( P < 0.00001). Forced expiratory flow at 75% of vital capacity (FEF75) decreased from 77% to 47% and 47% ( P < 0.00001). Peak expiratory flow rate (PEFR) declined from 101% to 66% ( P < 0.00001) and 86% ( P < 0.003). Maximal voluntary ventilation declined from 103% to 68% ( P < 0.00001) and 77% ( P < 0.00001). Only FVC ( P < 0.0003), FEV1.0 ( P < 0.02) and PEFR ( P < 0.00001) partially recovered postoperatively. Smoking history did not affect perioperative PETS. Pre-, but not postoperative FVC, FEV1.0, FEF50 and FEF75 were worse in valve than in CABG patients.
Conclusions: Pulmonary functions deteriorate significantly for at least 3.5 months after cardiac surgery. Preoperative cardiac ischaemic and failure symptoms are inversely related to perioperative PETS.     

肾区域组织氧饱和度预测紫绀型患儿心脏手术后急性肾损伤的效果

目的探讨紫绀型先天性心脏病患儿心脏手术围术期肾区域组织氧饱和度(RrSO_2)对术后急性肾损伤(AKI)的预测价值。方法选取心肺转流(CPB)下接受心脏手术的紫绀型先天性心脏病患儿36例,男22例,女14例,年龄≤1岁,分别于气管插管后5 min(T_1)、升主动脉夹闭后5 min(T_2)、升主动脉开放后5 min(T_3)、CPB结束(T_4)、超滤结束(T_5)、CPB结束后3 h(T_6)、CPB结束后8 h(T_7)、CPB结束后24 h(T_8)记录MAP、RrSO_2、鼻咽温,同时抽取动脉血和中心静脉血进行血气分析,记录动脉血氧饱和度(SaO_2)、动脉血Hb、乳酸(Lac)、中心静脉血氧饱和度(ScvO_2),根据改善全球肾脏病预后组织(KDIGO)诊断标准将患儿分为两组:急性肾损伤组(D组)和正常组(N组)。单因素分析两组患儿的临床资料,将不同时点MAP、RrSO_2、鼻咽温、Hb、SaO_2、Lac、ScvO_2值、有意义变量纳入二元Logistic回归分析,采用受试者工作特征(ROC)曲线分析RrSO_2对AKI的预测价值。结果 T_3—T_6时D组RrSO_2明显低于N组(P0.01)。两组不同时点MAP、鼻咽温、SaO_2、Hb、Lac和ScvO_2差异无统计学意义。二元Logistic回归分析显示,T_3—T_6时RrSO_2是紫绀型先天性心脏病患儿心脏术后AKI的危险因素(P0.05)。ROC曲线分析结果显示,T_3—T_6时RrSO_2临界值分别为60.2%、57.2%、55.0%、54.0%,敏感性分别为66.7%、83.3%、66.7%、83.3%,特异性分别为100%、92%、100%、75%,曲线下面积分别为0.896、0.861、0.792、0.840。结论 RrSO_2可作为紫绀型先天性心脏病患儿心脏AKI的一项无创预测指标。     

术中持续输注胰岛素对心肺转流心脏手术患者心肌血流灌注的影响

目的： 探讨术中持续输注胰岛素对心肺转流（CPB）心脏手术患者心肌血流灌注的影响。
方法： 选择择期行CPB心脏手术患者48例,男21例,女27例,年龄55～80岁,BMI 18～28 kg/m²,ASA Ⅱ—Ⅳ级。将患者随机分为两组：胰岛素组（I组,n=25）和对照组（C组,n=23）。两组采用相同麻醉方案。麻醉诱导后I组静脉输注胰岛素30 mU·kg^-1·h^-1、葡萄糖0.12 g·kg^-1·h^-1、氯化钾0.06 mmol·kg^-1·h^-1混合液,C组予以生理盐水10 ml/h输注,均输注至术毕。术中目标血糖值为6.1～11.1 mmol/L。于麻醉诱导后10 min（T₂）和术毕（T₆）行经食管超声心动图（TEE）检测,记录冠状静脉窦（CS）血流频谱、直径及肺静脉血流频谱,并计算CS净向前血流流速时间积分（VTI）。记录T₂、CPB前2 min（T₃）、CPB结束时（T₅₂）和T6时的股动脉平均动脉压（MAP）、中心静脉压（CVP）、每搏量（SV）、心脏指数（CI）及外周血管阻力指数（SVRI）。记录麻醉诱导前5 min（T₁）、T₃、CPB后30 min（T₄）、T₅、T₆、术后6 h（T₇）、术后12 h（T₈）及术后24 h（T₉）时血糖及乳酸浓度。记录术前1 d、术后1、2 d时超敏C反应蛋白（hs-CRP）、高敏肌钙蛋白I（hs-TnI）和肌酸激酶同工酶（CK-MB）水平。
结果： 与C组比较,I组T₆时CS净前向血流VTI及每分钟CS血流量均明显增加（P<0.05）,肺静脉心房收缩期峰值流速（ARp）明显减小（P<0.05）,T₅、T₆时SV和CI明显增大、SVRI明显降低（P<0.05）,T₇、T₈时乳酸浓度明显降低（P<0.05）,术后1、2 d时hs-CRP和CK-MB水平明显降低（P<0.05）,术后2 d时hs-TnI明显降低（P<0.05）。
结论： CPB心脏手术中持续输注胰岛素,同时维持血糖6.1～11.1 mmol/L,可改善心肌血流灌注,减轻术后炎症反应及心肌损伤。     

The effects of aprotinin and tranexamic acid on thrombin generation and fibrinolytic response after cardiac surgery

Background: Thrombin formation during cardiac surgery could result in disordered hemostasis and thrombosis. The aim of the study was to examine the effects of aprotinin and tranexamic acid on thrombin generation and fibrinolytic activity in patients undergoing cardiac surgery. Methods: Data were collected prospectively from 60 patients undergoing coronary artery bypass grafting using cardiopulmonary bypass (CPB). In a randomized sequence, 20 patients received aprotinin, 20 patients received tranexamic acid, and in 20 patients placebo was used. Results: Significant thrombin activity was found in all the studied patients. Thrombin generation was less in the aprotinin group than in the tranexamic acid and the placebo group (thrombin/anti‐thrombin III complexes 33.7 ± 3.6, 53.6 ± 7.0 and 44.2 ± 5.3 µg/l 2 h after CPB and F1 + 2 fragment 1.50 ± 0.10, 2.37 ± 0.37 and 2.04 ± 0.20 nmol/l 6 h after surgery, respectively). The inhibition of fibrinolysis was significant with both anti‐fibrinolytic drugs (d ‐dimers 0.427 ± 0.032, 0.394 ± 0.039 and 2.808 ± 0.037 mg/l 2 h after CPB, respectively). The generation of d ‐dimers was inhibited until 16 h after CPB in the aprotinin group. The plasminogen activation was significantly less in the aprotinin group (plasmin/anti‐plasmin complexes 0.884 ± 0.095, 2.764 ± 0.254 and 1.574 ± 0.185 mg/l 2 h after CPB, respectively). Conclusion: Thrombin formation is inevitable in coronary artery bypass surgery when CPB is used. The suppression of fibrinolytic activity, either with aprotinin or with tranexamic acid interferes with the hemostatic balance as evaluated by biochemical markers. Further investigations are needed to define the role of hemostatic activation in ischemic complications associated with cardiac surgery.     

阻塞性黄疸大鼠内引流术后血浆内皮素和肾血流量的关系

目的: 研究阻塞性黄疸(阻黄)大鼠胆道引流前后血浆内皮素水平和肾血流量的变化情况.方法: 将实验动物随机分为5组:胆管结扎组、假结扎组、阻黄内引流后2 d组、阻黄内引流后7 d组以及假引流对照组.分别检测各组的肝肾功能、肾血流量以及血浆内皮素水平,并进行组间对照.结果: ①胆管结扎10 d以后,血清SGPT和血清总胆红素显著升高,引流2 d后迅速下降,7 d后基本恢复到正常范围.②胆管结扎10 d以后,肾皮质血流量显著下降,同时血浆ET水平明显升高,引流2 d后血浆内皮素水平显著下降,但肾血流量直到术后7 d才有明显改善.结论: 发生阻黄以后出现的血浆内皮素水平升高和手术应激是造成术后并发肾功能衰竭的主要因素,术前内引流减黄可能是预防术后发生肾功能衰竭的有效手段.     

Relationship between intra- and postoperative oxygen transport and prolonged intensive care after cardiac surgery: a prospective study

Background: Prolonged intensive care is a rare but serious complication of cardiac surgery. It is required in less than 10% of operated patients but they use more than 30% of all the intensive care resources needed for cardiac surgery. The aim of our study was to describe the clinical course of the patients who need prolonged intensive care following cardiac surgery and to assess whether the intra- and postoperative oxygen transport variables are different in these patients as compared to patients with an uncomplicated course.
Methods: The study patients were divided into two groups according to the length of stay in the intensive care unit (ICU) after the operation: Group I, n=241, ICU-stay 5 days and Group II, n=20, ICU-stay≥5 days. Hemodynamic and oxygen transport data were prospectively obtained intra- and postoperatively and postoperative organ dysfunctions were recorded.
Results: The patients in the prolonged intensive care group tended to be older, have lower ejection fraction and longer cardiopulmonary bypass time. Postoperatively, this group had significantly increased oxygen extraction rate ( P =0.035, repeated measures for ANOVA). In the logistic regression analysis, in creased oxygen extraction (31% in Group I vs. 36% in Group II, P < 0.005) at 6 hours after arrival at the intensive care unit had the strongest independent association with the need for prolonged intensive care.
Conclusions: There was no significant relationship between the factors conventionally assumed to be risk factors for prolonged intensive care. Instead, an increase in whole body oygen extraction, reflecting a mismatch between the whole body oxygen demand and supply, was associated with the need for prolonged intensive care. Oxygen extraction increased to compensate for the reduced oxygen delivery, which in turn was caused by a lower arterial oxygen content.     

Dialysis and pediatric acute kidney injury: choice of renal support modality

Dialytic intervention for infants and children with acute kidney injury (AKI) can take many forms. Whether patients are treated by intermittent hemodialysis, peritoneal dialysis or continuous renal replacement therapy depends on specific patient characteristics. Modality choice is also determined by a variety of factors, including provider preference, available institutional resources, dialytic goals and the specific advantages or disadvantages of each modality. Our approach to AKI has benefited from the derivation and generally accepted defining criteria put forth by the Acute Dialysis Quality Initiative (ADQI) group. These are known as the risk, injury, failure, loss, and end-stage renal disease (RIFLE) criteria. A modified pediatrics RIFLE (pRIFLE) criteria has recently been validated. Common defining criteria will allow comparative investigation into therapeutic benefits of different dialytic interventions. While this is an extremely important development in our approach to AKI, several fundamental questions remain. Of these, arguably, the most important are “When and what type of dialytic modality should be used in the treatment of pediatric AKI?” This review will provide an overview of the limited data with the aim of providing objective guidelines regarding modality choice for pediatric AKI. Comparisons in terms of cost, availability, safety and target group will be reviewed.