Impact of cardiopulmonary bypass management on postcardiac surgery renal function

OBJECTIVE: Cardiac surgery on cardiopulmonary bypass (CPB) is associated with postoperative renal dysfunction and up to 4% of patients with normal preoperative renal function develop acute renal failure (ARF) requiring dialysis. According to recent investigations, CPB management is not evidence-based and, thus, current clinical CPB practice may favor renal dysfunction. The purpose of our study was to investigate if postcardiac surgery renal dysfunction is influenced by CPB management. METHODS: We selected three groups of patients with normal preoperative renal function who had been subjected to cardiac surgical procedures on CPB: 44 patients with postoperative ARF requiring hemofiltration/dialysis (ARF group), 51 patients with postoperative renal dysfunction not requiring hemofiltration/dialysis (serum creatinine increase > 0.5 mg/dl within 48 h postsurgery: CREA group), and 48 patients with normal postoperative renal function (Control group). The patients' on-line CPB records were analyzed for CPB duration, CPB perfusion pressure, CPB flow, and periods on CPB at a perfusion pressure <60 mmHg. On-CPB diuretic and vasoconstrictor medication was recorded. RESULTS: Patient demographics were similar for the three groups. In the ARF group, CPB duration was longer (166 +/- 77 [standard deviation, SD] min) compared to CREA (115 +/- 41 min; p < 0.001) and to Control groups (107 +/- 40 min; p < 0.001), and mean CPB flow was lower (2.35 +/- 0.36 l/min/m2) compared to CREA (2.61 +/- 0.35 l/min/m2; p = 0.0015) and to Control groups (2.51 +/- 0.33 l/min/m2; p = 0.09). Mean arterial pressure on CPB (ARF: 61 +/- 10; CREA: 60 +/- 7; CONTROL: 63 +/- 9 mmHg; p = 0.19) as well as furosemide and norepinephrine medication on CPB were similar for the groups. Compared to Control (46 +/- 26 min), CPB duration at arterial pressures <60 mmHg was longer in ARF (78 +/- 60 min; p = 0.034) and in CREA (62 +/- 36 min;p = 0.048). CONCLUSIONS: Our data suggest that current clinical CPB management impacts postoperative renal function. We found that patients with normal preoperative renal function who developed postoperative ARF had longer CPB duration, lower CPB perfusion flow, and longer periods on CPB at pressures < 60 mmHg compared to patients with no post CPB ARF. However, our data do not allow us to separate these CPB-related factors from the potential influence of perioperative low cardiac output syndrome as a cause for postoperative ARF. Thus, future clinical studies are required to elucidate CPB-induced ARF and to optimize CPB management for ARF prevention.     

IgA肾病肾血管病变危险因素的非条件logistic回归分析

目的 探讨IgA肾病肾血管病变的危险因素.方法 顾性分析2000年1月-2009年6月间经肾活检确诊的175例IgA肾病患者资料,其中有肾血管病变者93例,无肾血管病变者82例,进行对照研究.采用多因素非条件logistic回归模型分析影响IgA肾病肾血管病变的危险因素.结果 高血压[OR=11.593,P=0.001...     

Urinary cyclic AMP and post-traumatic acute renal failure.

Consecutive daily urinary excretion of cyclic AMP has been investigated in 16 patients with severe trauma or illness, five of whom developed acute renal failure (ARF). Fluctuations in the nucleotide excretion exceeded the range found in 20 healthy volunteers (1.26-14.74, mean 7.13+/-1.18 vs. 2.04-10.10, mean 5.07+/-2.21 micronmol/24 h). This resulted in a 41% increase of cAMP excretion in the group with normal renal function (P less than 0.003) with the highest individual increase of 87%. The excretion usually reached its peak by 24 h after trauma and its lowest value by the third day, (first day vs. third day; 7.82+/-4.23 vs. 3.96+/-2.58 micronmol/24 h, P less than 0.05 for a group of 11 patients), while creatinine clearance remained normal. In four patients with severe ARF, the mean urine volume was above control value but the cAMP excretion was reduced to 3.9 to 14.4% and in one patient with a mild ARF to 60.6%. Creatinine excretion of the group was less reduced than that of cAMP (41.2% vs. 19.6%, resp.). cAMP excretion declined proportionally with diminishing creatinine clearance. In the category of 33-65 ml/min it decreased by 33.4% to 3.39 micronmol+/-1.16 micronmol/24 h. cAMP/creatinine ratio proved to be a less sensitive indicator than cAMP/24 h. Daily output of cAMP and creatinine correlated highly with diuresis in ARF patients, controls (always P less than 0.001) and less in patients with normal renal function (P less than 0.02). Urinary cAMP appears to be a very sensitive and early indicator of the onset of ARF and subsequent recovery. This warrants its further study.     

Cystatin C对心脏手术患者肾功能的评估价值

目的 评价胱氨酸蛋白酶抑制荆C（Cystatin C）在心脏手术患者肾功能评估的应用价值。方法测定并统计心脏外科手术患者术前的Cystatin C、血清肌酐、手术后次晨的血清肌酐，并对部分患者手术前进行24h尿内生肌酐清除率的检查，分析Cystatin C、24h尿内生肌酐清除率及与手术前后血清肌酐变化之间的关系。结果Cystatin C对术后肌酐异常的敏感性为68．3％，特异性为16．6％，诊断符合率为68．9％。24h尿肌酐清除率的相关指标为62．5％、55．6％和66．7％。两者比较差异有显著性（P〈0．01）。两者联合应用，则相关指标分别为66．7％、77．8％和74．1％。结论Cystatin C是肾小球滤过率监测中的一个较敏感的指标。联合应用Cystatin C和24h尿内生肌酐清除率可以更准确地评估肾功能。     

Acute renal failure following open heart surgery: risk factors and prognosis

BACKGROUND: Acute renal failure (ARF) development after cardiac surgery carries high mortality and morbidity. METHODS: Out of 14437 consecutive patients undergoing open-heart surgery between January 1991 and May 2001, 168 (1.16%) developed postoperative ARF mandating hemodialysis. Possible perioperative risk factors, and the prognosis of this dreadful, often fatal complication were investigated. RESULTS: The mortality rate in this group was 79.7% (134 patients). The risk factors associated with postoperative ARF were advanced age (p=0.000), diabetes mellitus (p=0.000), hypertension (p=0.000), high preoperative serum creatinine levels (p=0.004), impaired left ventricular function (p= 0.002), urgent operation (p=0.000) or reoperation (p=0.007), prolonged cardiopulmonary bypass (CPB) (p =0.000) and aortic cross-clamp (ACC) (p =0.000) periods, level of hypothermia (p =0.000), concomitant procedures (p =0.000), low cardiac output state (p =0.000), re-exploration for bleeding or pericardial tamponade (p =0.000), and deep sternal or systemic infection (p = 0.000). Of those who could be discharged from hospital, renal functions were restored in 21 patients (12.5%); however, eight patients (4.7%) became hemodialysis dependent. The mean follow-up period was 5.7+/-3.2 years (range: 4 months to 13 years; a total of 195 patient-years), and 10-year survival was 58.6+/-10.2% in the discharged patients. CONCLUSIONS: ARF development after cardiac surgery often results in high morbidity and mortality. Recognizing risk factors permits the timely institution of proper treatment, which is the key to reducing untoward outcomes.     

Role of hemodilutional anemia and transfusion during cardiopulmonary bypass in renal injury after coronary revascularization: implications on operative outcome

OBJECTIVE: Acute renal injury and failure (ARF) after cardiopulmonary bypass (CPB) has been linked to low on-pump hematocrit (hematocrit). We aimed to 1) elucidate if and how this relation is modulated by the duration of CPB (TCPB) and on-pump packed red blood cell transfusions and 2) to quantify the impact of post-CPB renal injury on operational outcome and resource utilization. DESIGN: Retrospective review. SETTING: A Northwest Ohio community hospital. PATIENTS: Adult coronary artery bypass surgery patients with CPB but no preoperative renal failure. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We quantified post-CPB renal injury via 1) the peak postoperative change in serum creatinine (Cr) level relative to pre-CPB values (%DeltaCr) and 2) ARF, defined as the coincidence of post-CPB Cr > or =2.1 mg/dL and >2 times pre-CPB Cr. The separate effects of lowest hematocrit, intraoperative packed RBC transfusions, and TCPB on %DeltaCr and ARF were derived via multivariate regression, overlapping quintile subgroup analyses, and propensity matching. Lowest hematocrit (22.0% +/- 4.6% sd), TCPB (94 +/- 35 mins), and pre-CPB Cr (1.01 +/- 0.23 mg/dL) varied widely. %DeltaCr varied substantially (24 +/- 57%), and ARF was documented in 89 patients (5.1%). Both %DeltaCr (p < .001) and ARF (p < .001) exhibited sigmoidal dose-dependent associations to lowest hematocrit that were 1) modulated by TCPB such that the renal injury was exacerbated as TCPB increased, 2) worse in patients with relatively elevated pre-CPB Cr (> or =1.2 mg/dL), and 3) worse with intraoperative packed red blood cell transfusions (n = 385; 21.9%), in comparison with patients at similar lowest hematocrit. Operative mortality (p < .01) and hospital stays (p < .001) were increased systematically and significantly as a function of increased post-CPB renal injury. CONCLUSIONS: CPB hemodilution to hematocrit <24% is associated with a systematically increased likelihood of renal injury (including ARF) and consequently worse operative outcomes. This effect is exacerbated when CPB is prolonged with intraoperative packed red blood cell transfusions and in patients with borderline renal function. Our data add to the concerns regarding the safety of currently accepted CPB practice guidelines.     

Risk factors of early redialysis after weaning from postoperative acute renal replacement therapy

Objective The aim of this study was to identify risk factors for redialysis in postoperative patients with acute renal failure (ARF) who had previously been weaned from acute dialysis. Although recovery of renal function is anticipated in patients with ARF, no data have been reported on successful weaning from acute dialysis. Design and setting Retrospective observational case-control study in a 64-bed surgical ICU. Patients and methods Success in discontinuing dialysis was defined as cessation from dialysis for at least 30 days. A total of 304 postoperative patients who underwent acute renal replacement therapy in a surgical ICU between July 2002 and April 2005 were included. SOFA score biochemical data and renal function parameters were assessed on the day after the last session of renal replacement therapy, designated as day 0 (D0). Results We could wean 94 patients (30.9%) from acute dialysis for more than 5 days, and 64 of these (21.1%) were successfully weaned for at least 30 days. The independent predictors for resuming dialysis within 30 days were: (a) longer duration of dialysis (OR 1.06), (b) higher SOFA score on D0 (OR 1.44), (c) oliguria (urine output < 100cc/8 h; OR 4.17) on D1, and (d) age over 65 years (OR 6.35). The area under the ROC curve was 0.880. Two-way analysis of variance with repeated measurements over time showed a larger decline in SOFA score and an increase in urine output in patients with successful cessation of dialysis. Kaplan–Meier analysis showed a significant difference in early resumption of dialysis between patients with or without oliguria at D0. Conclusions More than two-thirds of patients weaned from postoperative acute dialysis for more than 5 days were free of dialysis for at least 30 days. Less urine output, longer duration of dialysis, age over 65 years, and higher disease severity score are predictive of a patient's redialysis after initial weaning from acute dialysis. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. The complete list of NSARF members is provided in the Acknowledgements. This study was financially supported by the Improving Dialysis Quality Research Funds, the Ta-Tung Kidney Foundation and Taiwan National Science Council (grant: NSC 95-2314-B-002-166). There are no conflicts of interest.     

Clinical factors in predicting acute renal failure caused by rhabdomyolysis in the ED

Purpose

This study aimed to determine the clinical factors in predicting acute renal failure (ARF) in rhabdomyolysis and investigate the potential risk of renal replacement therapy (RRT).

Basic Procedures

From 2006 to 2011, we retrospectively analyzed 202 patients 65 years or younger with a definite diagnosis of rhabdomyolysis and serum creatinine phosphokinase levels greater than 1000 IU/L. The related clinical factors were analyzed in the patients with ARF caused by rhabdomyolysis. In addition, receiver operating characteristic curves were used to establish the appropriate cutoff values of serum biomarkers in predicting ARF.

Main Findings

The most common causes of rhabdomyolysis were trauma (n = 54; 26.7%) and infections (n = 37; 18.3%). Of the 202 patients, 29 (14.4%) developed ARF, and RRT was indicated for 5 of these 29 patients. Predictive factors for ARF were dark urine, initial and peak serum myoglobin level, rhabdomyolysis caused by body temperature change, and an elevated serum potassium level. Receiver operating characteristic analysis showed that the best cutoff value of initial serum myoglobin level for predicting ARF was 597.5 ng/mL. Risk factors for RRT in patients with ARF were etiologies of rhabdomyolysis, peak blood urea nitrogen and creatinine levels, and the creatinine phosphokinase level on the third day as rhabdomyolysis developed.

Principal Conclusions

Age, dark urine, etiologies, serum levels of blood urea nitrogen, creatinine and potassium, and initial and peak serum myoglobin levels may serve as important factors in predicting ARF in patients with rhabdomyolysis. We suggest that the appropriate cutoff value of initial serum myoglobin for predicting ARF is 600 ng/mL.     

Pharmacokinetics of intraperitoneal cefepime in automated peritoneal dialysis.

OBJECTIVE: This study determined the pharmacokinetics of intraperitoneal (IP) cefepime in automated peritoneal dialysis (APD) patients. DESIGN AND METHODS: A prospective pharmacokinetic study was performed in 6 noninfected adult APD patients. All patients were administered a single IP dose of cefepime (15 mg/kg) over a 6-hour dwell. Patients then underwent a fixed APD regimen consisting of the first 6-hour dwell, followed by an 8-hour dialysate-free period and a subsequent series of 3 overnight APD exchanges. Blood and dialysate samples were collected at t = 0, 1, 2, 4, 6 (end of dwell), and 24 hours. Any urine produced during the study period was collected. Cefepime concentrations in serum, dialysate, and urine were determined by liquid chromatography mass spectrometry. Pharmacokinetic parameters were calculated assuming a mono-exponential model. RESULTS: One hour after IP administration, serum cefepime levels exceeded the minimum inhibitory concentration (8 microg/mL) for susceptible organisms. The mean serum and dialysate concentrations at 24 hours were 15.8 +/- 3.6 and 6.2 +/- 2.3 microg/mL respectively. Bioavailability was 84.3% +/- 6.2%, volume of distribution 0.34 +/- 0.07 L/kg, and serum half-life 13.8 +/- 3.2 hours. Total, peritoneal, and renal clearances were 16.5 +/- 4.4, 4.3 +/- 0.7, and 3.5 +/- 2.5 mL/minute, respectively. CONCLUSIONS: IP cefepime dosed at 15 mg/kg resulted in adequate serum concentrations in APD patients at 24 hours post dose. Pharmacokinetic predictions suggest that most APD and CAPD patients would achieve adequate serum cefepime concentrations if treated with standard doses of 1000 mg given IP once daily. Patients using APD regimens different from that used in this study, anuric patients, and those with significant residual renal function may require a more individualized approach.     

High volume peritoneal dialysis for acute renal failure.

BACKGROUND: Peritoneal dialysis (PD) is still widely used for acute renal failure (ARF) in developing countries despite concerns about its inadequacy. Continuous PD has been evaluated in ARF by analyzing the resolution of metabolic abnormality and normalization of plasma pH, bicarbonate, and potassium. Methodology: A prospective study was performed on 30 ARF patients who were assigned to high-dose continuous PD (Kt/V = 0.65 per session) via a flexible catheter (Tenckhoff) and automated PD with a cycler. Fluid removal, pH and metabolic control, protein loss, and patient outcome were evaluated. RESULTS: Patients received 236 continuous PD sessions; 76% were admitted to ICUs. APACHE II score was 32.2+/-8.65. BUN concentrations stabilized after 3 sessions, creatinine after 4, and bicarbonate and pH after 2. Fluid removal was 2.1+/-0.62 L/day. Creatinine and urea clearances were 15.8+/-4.16 and 17.3+/-5.01 mL/minute respectively. Normalized creatinine clearance and urea Kt/V values were 110.6+/-22.5 L/week/1.73 m(2) body surface area and 3.8+/-0.6 respectively. Solute reduction index was 41%+/-6.5% per session. Serum albumin values remained stable in spite of considerable protein losses (median 21.7 g/day, interquartile range 9.1-29.8 g/day). Regarding ARF outcome, 23% of patients presented renal function recovery, 13% remained on dialysis after 30 days of follow-up, and 57% died. CONCLUSION: High-dose continuous PD by flexible catheter and cycler was an effective treatment for ARF. It provided high solute removal, allowing appropriate metabolic and pH control, and adequate dialysis dose and fluid removal. Continuous PD can therefore be considered an alternative to other forms of renal replacement therapy in ARF.     

接受不同他汀治疗的冠状动脉旁路移植术后发生急性肾损伤的影响因素分析

目的:对比研究瑞舒伐他汀和阿托伐他汀对冠状动脉旁路移植术（coronary artery bypass grafting,CABG）患者急性肾损伤（acute kidney injury,AKI）发生的影响,并分析CABG术后AKI的影响因素。方法:回顾性收集2014年5月至2020年5月年龄大于18周岁、在山东大学附属临沂市人民医院心脏外科接受CABG术的550例患者为研究对象。根据患者术前是否常规应用瑞舒伐他汀或阿托伐他汀分为瑞舒伐他汀组（ n=322）、阿托伐他汀组（ n=125）和非他汀组（ n=103）。收集患者的人口统计学资料、CABG前后的临床资料和实验室检查结果。比较三组患者的尿素氮（blood urea nitrogen,BUN）、血清肌酐（serum creatinine,Scr）、肌酐清除率（creatinine clearance rate,Ccr）以及术后AKI发生情况;采用单因素分析和二分类Logistic回归分析探讨他汀对CABG术患者发生AKI的影响。 结果:与术前相比,550例患者术后BUN差异无统计学意义（ P>0.05）,Scr升高,Ccr降低,差异均有统计学意义（ P<0.01）。瑞舒伐他汀组术后BUN降低,差异有统计学意义（ P<0.01）,Scr、Ccr无显著变化（ P>0.05）;阿托伐他汀组术后Scr升高,差异有统计学意义（ P<0.01）,BUN、Ccr差异无统计学意义（ P>0.05）;非他汀组术后BUN、Scr升高,Ccr降低,差异均有统计学意义（ P<0.01）。瑞舒伐他汀组和阿托伐他汀组术后BUN、Scr均低于非他汀组,差异均有统计学意义（均 P<0.01）;Ccr高于非他汀组,差异有统计学意义（ P<0.01）。瑞舒伐他汀组BUN、Scr和阿托伐他汀组差异均无统计学意义（ P>0.05）,Ccr高于阿托伐他汀组,差异有统计学意义（ P<0.05）。三组间BUN、Scr、Ccr差异有统计学意义（ χ2值分别为48.925、22.677、34.426,均 P<0.01）。550例患者中AKI发生率为15.1%（83/550）,其中瑞舒伐他汀组9.6%（31/322）,阿托伐他汀组16.0%（20/125）,非他汀组31.1%（32/103）。瑞舒伐他汀组和阿托伐他汀组AKI发生率均低于非他汀组,差异有统计学意义（ χ2值分别为28.412、7.282, P<0.01）。多因素回归分析发现高血压病史（ OR=3.555,95% CI：1.959~6.451, P<0.01）、NHYA心功能Ⅲ/Ⅳ（ OR=2.438,95% CI：1.187~5.008, P=0.015）、血清肌酐水平升高（ OR=1.018,95% CI：1.003~1.032, P=0.016）、术中采用体外循环（ OR=2.936,95% CI：1.454~5.927, P=0.003）是CABG术后发生AKI的独立危险因素;而术前常规他汀治疗（ OR=0.490,95% CI：0.247~0.974, P=0.042）和血清白蛋白水平（ OR=0.920,95% CI：0.856~0.990, P=0.026）是CABG术后发生AKI的保护因素。 结论:CABG术后发生AKI常见,术前常规应用瑞舒伐他汀或阿托伐他汀以及术前高血清白蛋白水平均可以保护肾功能,降低术后AKI发生率,是CABG术后AKI的保护因素,而高血压病史、NHYA心功能Ⅲ/Ⅳ、术前血清肌酐水平升高、术中采用体外循环是CABG术后发生AKI的独立危险因素。     

Use of 2-hour creatinine clearance to guide cessation of continuous renal replacement therapy

Purpose

A simple test that could guide successful cessation of continuous renal replacement therapy (CRRT) in critically ill patients would be clinically useful. This study aimed to investigate whether a 2-hour creatinine clearance (2h-CrCl) measurement could more accurately predict successful cessation of CRRT than serum creatinine or urine output alone.

Materials and Methods

This retrospective study identified all patients admitted to a university teaching hospital intensive care unit who received CRRT and had a 2h-CrCl measurement performed in the 12 hours preceding CRRT cessation. The ability of 2h-CrCl to predict successful discontinuation of CRRT was compared to other renal indices.

Results

Of 85 patients who had 2h-CrCl performed prior to CRRT cessation 53 (62.4%)(success group) remained dialysis free 7 days after CRRT cessation. 2h-CrCl was a better predictor of remaining CRRT free at day 7 (OR, 1.108 [1.05–1.17] per 1 mL/min increase in 2 hours CrCl, P < .001) than urine output, serum creatinine or age. A 2h-CrCl value of 23 mL/min had a sensitivity, specificity and positive predictive value for remaining CRRT free at day 7 of 75.5%, 84.4%, and 88.8%, respectively.

Conclusion

2h-CrCl may be a useful measurement to help guide discontinuation from CRRT.     

Pharmacokinetics of cefpiramide in volunteers with normal or impaired renal function.

The pharmacokinetics of a single 2.0-g intravenous dose of cefpiramide in patients with normal or impaired renal function were studied. Serial concentrations in serum and urine were measured by using high-performance liquid chromatography, and the effect of the concentration in serum on protein binding was assessed. Thirty patients (ten with creatinine clearances of greater than 80 ml/min, ten with creatinine clearances between 10 and 80 ml/min, and ten on dialysis) were studied. The concentration-time curve of cefpiramide was best described by an open two-compartment model. The elimination half-lives in patients with normal or impaired renal function or those on dialysis were 5.41 +/- 1.44, 8.3 +/- 2.82, and 8.38 +/- 4.06 h, respectively, and the serum clearances in the same groups were 2.0 +/- 0.84, 1.29 +/- 0.45, and 2.04 +/- 1.10 liters/h, respectively. There were no significant differences in any of the parameters among the three groups of patients. In patients with normal or impaired renal function, protein binding varied between 93.0 +/- 1.3% at 304.4 micrograms/ml and 99.3 +/- 0.8% at 41.1 micrograms/ml and was linearly and inversely related to the cefpiramide concentration in serum. In patients on dialysis, protein binding was significantly lower (P less than 0.05) and varied between 88.5 +/- 7.1% at 173.4 micrograms/ml to 94.9 +/- 4.8% at 46.8 micrograms/ml. In patients with normal or abnormal renal function, renal cefpiramide clearance decreased linearly with declining renal function, whereas plasma clearance was maintained. Therefore, nonrenal elimination becomes more important as renal impairment progresses.     

异基因造血干细胞移植后急性肾衰竭的临床研究

本研究探讨异基因造血干细胞移植（allo—HSCT）后急性肾衰竭（acuterenalfailure,ARF）的发生率、危险因素以及对患者预后的影响。采用回顾性研究方法,对86例allo—HSCT患者的资料进行了分析。采用单因素分析及多因素Logistic回归模型分析,研究了ARF发生的危险因素。使用Cox回归法分析了ARF与allo—HSCT患者生存时间的关系。结果表明：ARF发生率为31．40％,发病中位时间为allo—HSCT后59．5天。单因素及多因素分析发现,移植前肾脏疾病、败血症或感染中毒性休克、高胆红素血症为allo—HSCT后ARF发生的独立危险因素。同时,ARF是影响allo—HSCT患者生存的独立危险因素。结论：Allo—HSCT后ARF发生率高;败血症或感染中毒性休克、高胆红素血症、既往肾脏病史是allo—HSCT后ARF发生的独立危险因素;ARF是影响allo—HSCT患者生存时间的独立危险因素。     

Acute renal failure in pregnancy

Acute renal failure (ARF) during pregnancy is a rare event. However, the care of the woman diagnosed with ARF is a challenge for the perinatal care team. The physiologic hydronephrosis and hydroureter of pregnancy alters clinical parameters for assessing the woman diagnosed with ARF. Urinary stasis and enhanced filtration predisposes to alterations in 24-hour urine evaluations, increased urinary creatinine excretion, and lower BUN and serum creatinine values. If the renal system becomes compromised, the woman is at risk for acidemia, fluid and electrolyte imbalances, and pregnancy compromise. The perinatal nurse must have an understanding of normal pregnancy physiology and an appreciation for how pregnancy physiology may alter renal assessments. Furthermore, the nurse must know the impact that ARF can have on maternal status and fetal well-being. Astute, continuous assessments of maternal and fetal status are required to detect subtle changes. While maternal status is the primary concern, it must not be forgotten that a change in fetal status may be the first indication of underlying maternal compromise.     

Four hour creatinine clearance is better than plasma creatinine for monitoring renal function in critically ill patients

ABSTRACT: INTRODUCTION: Acute kidney injury (AKI) diagnosis is based on an increase in plasma creatinine, which is a slowly changing surrogate of decreased glomerular filtration rate. We investigated whether serial creatinine clearance, a direct measure of the glomerular filtration rate, provided more timely and accurate information on renal function than serial plasma creatinine in critically ill patients. METHODS: Serial plasma creatinine and 4-hour creatinine clearance were measured 12-hourly for 24 hours and then daily in 484 patients. AKI was defined either as > 50% increase in plasma creatinine from baseline, or > 33.3% decrease in creatinine clearance. The diagnostic and predictive performance of the two AKI definitions were compared. RESULTS: Creatinine clearance decrease diagnosed AKI in 24% of those not diagnosed by plasma creatinine increase on entry. These patients entered the ICU sooner after insult than those diagnosed with AKI by plasma creatinine elevation (P = 0.0041). Mortality and dialysis requirement increased with the change in creatinine clearance-acute kidney injury severity class (P = 0.0021). Amongst patients with plasma creatinine < 1.24 mg/dl on entry, creatinine clearance improved the prediction of AKI considerably (Net Reclassification Improvement 83%, Integrated Discrimination Improvement 0.29). On-entry, creatinine clearance associated with AKI severity and duration (P < 0.0001) predicted dialysis need (area under the curve: 0.75) and death (0.61). A > 33.3% decrease in creatinine clearance over the first 12 hours was associated with a 2.0-fold increased relative risk of dialysis or death. CONCLUSIONS: Repeated 4-hour creatinine clearance measurements in critically ill patients allow earlier detection of AKI, as well as progression and recovery compared to plasma creatinine. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN012606000032550.     

Recovery of renal function in Black South African patients with malignant hypertension: superiority of continuous ambulatory peritoneal dialysis over hemodialysis.

OBJECTIVE: To describe recovery of renal function (RC) in Black South African patients with primary malignant hypertension (MHT) and end-stage renal failure, according to the type of dialysis provided. DESIGN: A retrospective analysis of the records of 31 patients with MHT. SETTING: A university-based, large tertiary-care hospital and its community-based satellite continuous ambulatory peritoneal dialysis (CAPD) clinics. PATIENTS: Only patients with renal failure caused by MHT and who were on dialysis between January 1997 and June 2000. There were 11 patients on peritoneal dialysis (PD) that regained renal function; 11 patients on hemodialysis (HD), none of whom recovered renal function; and 9 patients on PD who did not recover renal function during the same time period. OUTCOME MEASURES: The groups were investigated for variables that might predict RC. RESULTS: Peritoneal dialysis compared with HD was highly significant as an indicator of RC (p < 0.0001), with 60% of patients on PD regaining renal function, versus 0% on HD. Median time to recovery was 300 (150 -365) days. There was no significant difference in decline of mean arterial pressure (MAP) between the groups; MAP declined significantly in all groups (p = 0.00002). All groups received similar drug therapy. In the RC group, initial MAP, kidney size, and urine output tended to be higher and creatinine lower (p = not significant). Dialysis adequacy was similar in the different groups. CONCLUSIONS:This retrospective study suggests there may be benefit from PD as the primary form of dialysis when patients have MHT as a cause of their renal failure. Possible predictors of RC include blood pressure control, initial MAP, initial serum creatinine, initial urine output, and kidney size. Time should be allowed for RC before transplantation is undertaken. Prospective studies are needed to confirm the benefit of CAPD in patients with MHT.     

Phase II, randomized, controlled trial of high-dose N-acetylcysteine in high-risk cardiac surgery patients

OBJECTIVE: To assess the effect of high-dose N-acetylcysteine on renal function in cardiac surgery patients at higher risk of postoperative renal failure. DESIGN: Multiblind, placebo-controlled, randomized, phase II clinical trial. SETTING: Operating rooms and intensive care units of two tertiary referral hospitals. PATIENTS: A total of 60 cardiac surgery patients at higher risk of postoperative renal failure. INTERVENTIONS: Patients were allocated to either 24 hrs of high-dose N-acetylcysteine infusion (300 mg/kg body weight in 5% glucose, 1.7 L) or placebo (5% glucose, 1.7 L). MEASUREMENTS AND MAIN RESULTS: The primary outcome measure was the absolute change in serum creatinine from baseline to peak value within the first five postoperative days. Secondary outcomes included the relative change in serum creatinine, peak serum creatinine level, serum cystatin C, and in urinary output. Further outcomes were needed for renal replacement therapy, length of ventilation, and length of stay in the intensive care unit and hospital. Randomization was successful and patients were well balanced for preoperative and intraoperative characteristics. There was no significant attenuation in the increase in serum creatinine from baseline to peak when comparing N-acetylcysteine with placebo (64.5 +/- 91.2 and 38.0 +/- 42.4 mumol/L, respectively; p = .15). Also, there was no attenuation in the increase in serum cystatin C from baseline to peak for N-acetylcysteine compared with placebo (0.45 +/- 0.43 and 0.30 +/- 0.33 mg/L, respectively; p = .40). Likewise, there was no evidence for differences in any other clinical outcome. CONCLUSIONS: In this phase II, randomized, controlled trial, high-dose N-acetylcysteine was no more effective than placebo in attenuating cardiopulmonary bypass-related acute renal failure in high-risk cardiac surgery patients.