Initial lactate levels linked to oliguria in term neonates with perinatal asphyxia.

BACKGROUND: Oliguria is a sign of impaired kidney function and has been shown to be an early predictor of adverse prognoses in patients with acute kidney injury. The relationship between urine output (UOP) and early lactate levels in neonates with perinatal asphyxia (PA) has not been extensively explored. This study aimed to investigate the link between oliguria during the first 24 h of life and early lactate levels in neonates with PA. METHODS: The medical records of 293 term neonates with asphyxia from 9216 hospitalized newborns were retrospectively analyzed, including 127 cases designated as the oliguria group and 166 cases as controls. Peripheral arterial blood gas after PA and UOP within 24 h after birth were analyzed. Logistic regression analyses and receiver operating characteristic curve analysis were conducted. RESULTS: Oliguria occurred in 43.34% of neonates with PA. The median UOP of the oliguria and control groups were 0.65 and 1.46 mL/kg/h, respectively. Elevated lactate levels after PA are an independent risk factor for oliguria in the following 24 h (p = 0.01; OR: 1.19; 95%CI: 1.04-1.35) and show a moderate discriminatory power for oliguria (AUC = 0.62). Using a cut off value of 8.15 mmol/L, the positive and negative predictive values and the specificity were 59.34%, 63.86%, and 78.30%, respectively. CONCLUSION: Neonates with elevated lactate levels after PA face a risk of oliguria in the following 24 h. Based on early elevated lactate levels after resuscitation, especially ≥ 8.15 mmol/L, meticulously monitoring UOP will allow this vulnerable population to receive early, tailored fluid management and medical intervention.

Acute kidney injury after liver surgery: does postoperative urine output correlate with postoperative serum creatinine?

BACKGROUND: Acute kidney injury (AKI) after hepatectomy occurs in around 10% of cases. AKI is often defined based only on postoperative serum creatinine increase. This study aimed to assess if postoperative urine output (UO) correlated with serum creatinine after hepatectomy. METHODS: All consecutive hepatectomy patients (2010-2016) were assessed. AKI was defined according to KDIGO criteria: serum creatinine increase ≥26.5 µmol/l, creatinine increase ≥1.5x baseline creatinine, or postoperative oliguria. Oliguria was defined as daily mean UO <0.5 mL/kg/h. AKI was subdivided into creatinine-based or oliguria-based AKI according to the defining criterion. RESULTS: Out of 285 patients, AKI was observed in 79 cases (28%). Creatinine-based AKI occurred in 25 patients (9%) and oliguria-based only AKI in 54 patients (19%). Ten patients fulfilled both criteria (4%). Postoperative UO correlated poorly with postoperative serum creatinine level in both whole cohort (rho = -0.34, p <0.001) and AKI subgroup (rho = -0.189, p = 0.124). No association was found between postoperative oliguria and postoperative serum creatinine increase (HR = 0.5, 95%CI: 0.2-1.9, p = 0.341). On multivariable analysis, operation duration >360 minutes was the only predictor of creatinine increase (HR = 3.6, 95%CI: 1.1-11.4, p = 0.032). CONCLUSION: Postoperative UO showed poor correlation with postoperative serum creatinine both in all patients and AKI patients. Surgery duration >360 minutes appeared as the only independent predictor of postoperative serum creatinine increase.

Association Between Intraoperative Oliguria and Acute Kidney Injury After Major Noncardiac Surgery.

BACKGROUND: Acute kidney injury (AKI) occurs in 6.1%-22.4% of patients undergoing major noncardiac surgery. Previous studies have shown no association between intraoperative urine output and postoperative acute renal failure. However, these studies used various definitions of acute renal failure. We therefore investigated the association between intraoperative oliguria and postoperative AKI defined by the serum creatinine criteria of the Risk, Injury, Failure, Loss, and End-stage kidney disease (RIFLE) classification. METHODS: In this single-center, retrospective, observational study, we screened 26,984 patients undergoing elective or emergency surgery during the period September 1, 2008 to October 31, 2011 at a university hospital. Exclusion criteria were age <18 years; duration of anesthesia <120 minutes; hospital stay <2 nights; local anesthesia only; urologic or cardiac surgery; coexisting end-stage kidney disease; and absence of serum creatinine measurement, intraoperative urine output data, or information regarding intraoperative drug use. Multivariable logistic regression analysis was used as the primary analytic method. RESULTS: A total of 5894 patients were analyzed. The incidence of postoperative AKI was 7.3%. By multivariable analysis, ≥120 minutes of oliguria (odds ratio = 2.104, 95% CI, 1.593-2.778; P < .001) was independently associated with the development of postoperative AKI. After propensity-score matching of patients with ≥120 and <120 minutes of oliguria on baseline characteristics, the incidence of AKI in patients with ≥120 minutes of oliguria (n = 827; 10%) was significantly greater than that in those with <120 minutes of oliguria (n = 827; 4.8%; odds ratio = 2.195, 95% CI, 1.806-2.668; P < .001). CONCLUSIONS: Contrary to previous studies, we found that intraoperative oliguria is associated with the incidence of AKI after major noncardiac surgery.

Nephroprotective Effect of EDL Peptide at Acute Injury of Kidneys of Different Genesis.

EDL peptide produced a nephroprotective effect on experimental models gentamycin-induced nephropathy and ischemia/reperfusion kidney injury in rats. The nephroprotective effect of EDL peptide manifested in prevention of oliguria and retention azotemia, a decrease in proteinuria and sodium excretion, prevention of critical decrease in activities of antioxidant enzymes, suppression of LPO, and normalization of energy supply to kidneys cells. Our findings confirm the prospects of further studies of the nephroprotective properties of peptide EDL in various pathologies of the kidneys.

Increased urinary neutrophil gelatinase-associated lipocalin in very-low-birth-weight infants with oliguria and normal serum creatinine.

BACKGROUND: In infants, oliguria is defined as a urine output of <1.5 mL/kg/h. The aim of our study was to assess the impact of oliguria on urinary neutrophil gelatinase-associated lipocalin (NGAL) and serum cystatin C (CysC) levels in very-low-birth-weight infants (VLBWIs) with a normal serum creatinine (Cr) level. METHODS: Fifty-seven VLBWIs were enrolled in the study. Urinary NGAL, serum CysC and Cr levels and urinary NGAL/Cr ratios were measured. Infants with Apgar scores of >5 at 5 min and/or a serum Cr level of >1.5 mg/dL or those treated for patent ductus arteriosus were excluded. In case of antibiotic treatment, blood and urine samples were collected at ≥48 h after discontinuation of antibiotic treatment. RESULTS: There was a significant difference in gestational age between infants with oliguric episodes during hospitalization and those without, but not in birth weight, perinatal or postnatal factors. Gestational age was negatively correlated with urinary NGAL and serum CysC levels and urinary NGAL/Cr ratio (p < 0.05), whereas postnatal age was negatively correlated with serum Cr level and urinary NGAL/Cr ratio (p < 0.05). Of the 117 urine and blood samples collected, 25 (21.4%) were obtained from neonates with oliguric episodes. After adjusting for gestational age and postnatal age, comparison of samples collected in infants with and without oliguric episodes revealed significant differences in the mean level of urinary NGAL and in the urinary NGAL/Cr ratio, but not in mean serum CysC or serum Cr levels. The urinary NGAL level [area under the curve (AUC) 0.886, 95% confidence interval (CI) 0.814-0.937] and urinary NGAL/Cr ratio (AUC 0.853, 95% CI 0.775-0.911) showed significantly greater discrimination for oliguria than serum CysC (AUC 0.610, 95% CI: 0.515-0.699) or serum Cr (AUC 0.747, 95%CI 0.659-0.823) levels. CONCLUSIONS: Urinary NGAL level and urinary NGAL/Cr ratio were more sensitive markers for the presence of oliguria in VLBWIs with normal serum Cr levels than serum CysC level.

Oliguria without serum creatinine increase after living donor liver transplantation is associated with adverse post-operative outcomes.

BACKGROUND: Acute kidney injury (AKI) is a common complication after liver transplantation and is associated with significant morbidity and mortality. Although clinical guidelines recommend defining AKI based on serum creatinine increase and oliguria, the validity and utility of the oliguric component of AKI definition remains largely unexplored. This study examined the incidence and the impact on clinical outcomes of oliguria meeting the urine output criterion of AKI in patients undergoing liver transplantation. The authors hypothesised that oliguria was an independent risk factor for adverse post-operative outcomes. METHODS: This study retrospectively examined 320 patients who underwent living donor liver transplantation at our centre. AKI stages were allocated according to recent guidelines based on serum creatinine or urine output within 7 days of surgery. RESULTS: The incidence of oliguria meeting the urine output criterion of AKI was 50.3%. Compared with creatinine criterion alone, incorporating oliguria into the diagnostic criteria dramatically increased the measured incidence of AKI from 39.7% to 62.2%. Compared with patients diagnosed without AKI using either criterion, oliguric patients without serum creatinine increase had significantly longer intensive care unit stays (median: 5 vs. 4 days, P = 0.016), longer hospital stays (median: 60 vs. 49 days, P = 0.014) and lower chronic kidney disease-free survival rate on post-operative day 90 (54.2% vs. 73.3%, P = 0.008). CONCLUSION: Oliguria is common after liver transplantation, and incorporating oliguria into the diagnostic criteria dramatically increases the measured incidence of AKI. Oliguria without serum creatinine increase was significantly associated with adverse post-operative outcomes.

Prediction of urine volume soon after birth using serum cystatin C.

BACKGROUND: Urine volume is an important clinical finding particularly during the early neonatal period. Oliguria is not a sign of impaired renal function but also a predictive factor for various complications and prognoses. It has been postulated that serum cystatin C (S-CysC) is a more sensitive biomarker for renal function than serum creatinine (S-Cr) in both adults and children. The objective of the current study was to investigate whether urine volume during 24 h after birth can be predicted using S-CysC. METHODS: The subjects were 87 infants. The average gestational age was 34.7 ± 2.9 weeks and the average birth weight was 2135 ± 614 g. Blood samples were obtained from either the umbilical cord or the peripheral veins or artery of the newborn at birth. Data regarding the amount of urine volume and fluid intake during the first 24 h of life, maternal S-Cr and S-CysC levels within 48 h before delivery, and neonatal S-Cr and S-CysC levels at birth were collected from the medical records. RESULTS: A significantly positive correlation was observed between maternal and neonatal S-Cr levels (r = 0.84, p < 0.0001) but not between maternal S-Cr levels and neonatal S-CysC levels (r = -0.069, p = 0.52). A significant negative correlation was seen between neonatal S-CysC levels and urine volume (r = -0.47, p < 0.0001). CONCLUSION: The present study findings indicate that it may be possible to use S-CysC levels at birth to predict urine volume during the first 24 h of life.

Failure of renal biomarkers to predict worsening renal function in high-risk patients presenting with oliguria.

PURPOSE: Oliguria is a common symptom in critically ill patients and puts patients in a high risk category for further worsening renal function (WRF). We performed this study to explore the predictive value of biomarkers to predict WRF in oliguric intensive care unit (ICU) patients. PATIENTS AND METHODS: Single-center prospective observational study. ICU patients were included when they presented a first episode of oliguria. Plasma and urine biomarkers were measured: plasma and urine neutrophil gelatinase-associated lipocalin (pNGAL and uNGAL), urine α1-microglobulin, urine γ-glutamyl transferase, urine indices of tubular function, cystatin C, C terminal fragment of pro-arginine vasopressin (CT-ProAVP), and proadrenomedullin (MR-ProADM). RESULTS: One hundred eleven patients formed the cohort, of whom 41 [corrected] had worsening renal function. Simplified Acute Physiology Score (SAPS) II was 41 (31-51). WRF was associated with increased mortality (hazard ratio 8.65 [95 % confidence interval (CI) 3.0-24.9], p = 0.0002). pNGAL, MR-ProADM, and cystatin C had the best odds ratio and area under the receiver-operating characteristic curve (AUC-ROC: 0.83 [0.75-0.9], 0.82 [0.71-0.91], and 0.83 [0.74-0.90]), but not different from serum creatinine (Screat, 0.80 [0.70-0.88]). A clinical model that included age, sepsis, SAPS II, and Screat had AUC-ROC of 0.79 [0.69-0.87]; inclusion of pNGAL increased the AUC-ROC to 0.86 (p = 0.03). The category-free net reclassification index improved with pNGAL (total net reclassification index for events to higher risk 61 % and nonevents to lower 82 %). CONCLUSIONS: All episodes of oliguria do not carry the same risk. No biomarker further improved prediction of WRF compared with Screat in this selected cohort of patients at increased risk defined by oliguria.

A prospective assessment of renal oxygenation in children undergoing laparoscopy using near-infrared spectroscopy.

BACKGROUND: This study was designed to determine whether a decrease in renal oxygenation occurs during CO2 pneumoperitoneum in children with normal renal function undergoing laparoscopy. METHODS: Near infrared spectroscopy (NIRS) probes were applied to both the lateral flank (T10-L2) and lateral cerebral area of all patients with normal renal function undergoing a laparoscopic procedure. Information was recorded in 5-s intervals for 15-min before, during, and for 15-min after pneumoperitoneum insufflation and desufflation. Simultaneously, additional hemodynamic parameters (arterial saturation, mean arterial pressure, end tidal CO2, and urine output) were recorded every 5-min. Pneumoperitoneum pressures used were: 0-1 month old, <6 mmHg; 2-12 months old, <8 mmHg; 1-2 years old, <10 mmHg, and 2-8 years old, <12 mmHg. The lowest possible pressure was used to obtain adequate vision. RESULTS: Twenty-nine patients were enrolled in the study. Renal regional oxygen saturation (rSO2) did not decrease significantly between baseline (preinsufflation), insufflation, and desufflation of the pneumoperitoneum (p = 0.343). Meta-analysis of this data demonstrated a pooled weighted difference of -1.4 (-3.5 to 0.54), confirming no significant change. A significant increase in cerebral rSO2 occurred during the insufflation period of the CO2 pneumoperitoneum (p = 0.001). Heart rate (F = 11.05; p < 0.001) and mean arterial pressure (MAP) (F = 19.2; p < 0.001) also increased significantly during the laparoscopy. No significant correlation was identified between fluid input and urine output during the laparoscopy (r = 0.012; p = 0.953). CONCLUSIONS: Renal hypoxia does not occur during laparoscopic surgery in children if the minimum age-appropriate intra-abdominal pressures are used. Alternative causes must account for the oliguria and anuria demonstrated in children undergoing laparoscopy.

The influence of mean arterial blood pressure during cardiopulmonary bypass on postoperative renal dysfunction in elderly patients.

The aim of the study was to find out if there is an optimal mean arterial blood pressure (MABP) during cardiopulmonary bypass (CPB) for renal function in elderly patients during the early postoperative period. We analysed the data of 122 patients >70 years of age with normal preoperative renal function who had been subjected to coronary artery bypass grafting (CABG) procedures on CPB. Patients were divided into 3 groups, according to MABP during CPB: group MP (n=50) included patients whose MABP was maintained between 60-70 mmHg; group LP (n=36), the MABP was <60 mmHg; and group HP (n=36) where the MABP was >70 mmHg. The patients' clinical data were evaluated during the first three postoperative days. The rate of renal impairment (urine output <50ml/h) in the early postoperative period after cardiac surgery did not differ among the groups. Oliguria developed in 3 patients (6%) of the MP group, in 2 patients (5.6%) in the LP group and in 6 patients (16.7%) in the HP group (χ(2)=3.6, df=2, p=0.161). Evaluation of MABP on renal excretion showed that there was no difference in urine output among the groups. Serum creatinine levels at the end of the first postoperative day in groups MP, LP and HP were 102.7±20.1, 116.4±58.6 and 113.2±39.8 µmol/L, respectively (F=0.5, df=2, p=0.640). There were no significant differences among the groups at the end of the second and the third day either. Volume balance at the end of surgery and during the early postoperative period was similar in all groups. The need for diuretics did not differ among the groups. The length of postoperative hospital stay was not significantly different among the groups. Our study did not reveal any relationship between a MABP of 48-80 and postoperative renal dysfunction in elderly patients after CABG surgery.

Life-threatening hypercalcemia in patients with rhabdomyolysis-induced oliguric acute renal failure.

BACKGROUND: In a third of patients presenting with rhabdomyolysis-induced acute renal failure (ARF), a biphasic plasma calcium profile may occur. METHODS: We report a case of rhabdomyolysis-induced ARF presenting hypocalcemia during oliguria, followed by a severe hypercalcemia in the polyuric phase. A hypocalcemia-induced acute increase of plasma parathyroid hormone in the early stage of ARF was followed by a down-regulation of parathyroid hormone, 1,25(OH)2 vitamin D and 25(OH) vitamin D during the renal function recovery, associated with an acute hypercalcemia. The plasma calcium increase induced in our patient severe neurological disturbances, life-threatening short QT interval and Brugada-like syndrome at risk of malignant arrhythmias. This complication was treated by hemodialysis and pamidronic acid infusion. RESULTS: This case confirms that the pathogenesis of the biphasic calcium profile may be related to the massive calcium uptake in the ischemic muscle cells during oliguria, followed by a muscle calcium release later in the polyuric stage of ARF. Therefore, the behavior of calciotropic hormones may be the consequence rather than the cause of plasma calcium changes. CONCLUSIONS: We would like to emphasize the danger of sudden death that may occur in the recovery phase of rhabdomyolysis-induced ARF when the physician might be wrongly convinced that the major risks have disappeared.

Life-threatening tertiary hyperparathyroidism in the critically ill.

BACKGROUND: Tertiary hyperparathyroidism typically occurs in patients who have recovered from renal failure after renal transplantation. This report describes a syndrome of tertiary hyperparathyroidism after recovery from multiple organ failure (MOF) with acute oliguric renal failure (AORF). METHODS: Six patients with MOF including AORF are presented. Increased parathyroid hormone (PTH) levels were documented as early as 3 weeks after injury or septic insult and remained increased in some patients for several weeks. RESULTS: The resultant increase in calcium levels led to recurrent bouts of bradycardia, often leading to asystole requiring cardiopulmonary resuscitation. Hypercalcemic-induced bradycardia was refractory to hydration, loop diuresis, atropine, and external pacing. Definitive treatment requires bisphosphonate therapy, which must be repeated until organ function has returned to normal. CONCLUSIONS: A new syndrome of life-threatening tertiary hyperparathyroidism is described in patients with critical illness. This syndrome probably is being overlooked frequently in critical care units. Early diagnosis and prophylactic treatment with bisphosphonate may preclude the life-threatening cardiac arrhythmias.

Oliguria during corrective spinal surgery for idiopathic scoliosis: the role of antidiuretic hormone.

Patients undergoing surgery for idiopathic scoliosis were studied to determine the incidence and aetiology of oliguria during the perioperative period and to evaluate the efficacy of low dose dopamine in preventing its occurrence. Thirty patients, aged 6-18 years undergoing elective surgery were studied. Anaesthesia was standardized. Patients were randomized to receive either dopamine infusion (3 micrograms.kg-1.min-1) (Group A) (n = 15) or dextrose infusion (control) (Group B) (n = 15). Serum and urinary electrolytes and osmolalities and serum antidiuretic hormone (ADH) concentrations were measured. Urine output and haemodynamic parameters were recorded. Intraoperative oliguria occurred in 7% of patients in Group A and 47% in Group B (P < 0.05). Postoperative oliguria occurred in 20% of patients in Group A and 47% in Group B (P > 0.05). Urine and serum biochemical analysis revealed a statistically significant decrease in serum sodium and osmolality (P < 0.005) and an increase in urinary sodium and osmolality in both groups. Serum ADH concentrations were increased in both groups (P < 0.05), returning to baseline 18 h postoperatively. We conclude that oliguria during corrective spinal surgery occurs in association with excess ADH secretion as opposed to perioperative hypovolaemia. Dopamine increases urine output in the perioperative period but does not prevent the release of ADH and its subsequent biochemical effects.

Impact of continuous hemofiltration on cytokines and cytokine inhibitors in oliguric patients suffering from systemic inflammatory response syndrome.

The impact of continuous hemofiltration (CHF) using a polyacrylonitrile membrane on the kinetics of tumor necrosis factor alpha (TNF alpha), interleukin-1 beta (IL-1 beta), and their inhibitors (soluble TNF receptors [sTNFrI, sTNFrII], interleukin-1 receptor antagonist [IL-1Ra]) was assessed in nine oliguric patients suffering from systemic inflammatory response syndrome. Blood and plasma flow (Qb, Qp), sieving coefficient (SC), plasma and ultrafiltrate clearances (Kp, Kuf), and plasma extraction rates (ERp) were calculated at different time points using standard formulas. No significant improvement of hemodynamics or gas exchange was noted following HF but a significant increase in serum bicarbonate occurred after 24 h (P < 0.05). TNF alpha was detected in plasma from all patients (153 +/- 2.3 pg/mL [mean +/- SEM]). None of the patients had detectable IL-1 beta levels. High levels of the TNF receptors (sTNFrI 20.338 +/- 2.431 pg/mL; sTNFrII 17.839 +/- 2.630 pg/mL) and IL-1Ra (19.775 +/- 3.943 pg/mL) were found in all patients. Upon initiation of hemofiltration (HF), the mean individual sTNFrI/TNF alpha ratio amounted to 269 +/- 84.6 and the sTNFrII/TNF alpha ratio to 249 +/- 91.8. Mean ultrafiltrate volume (Vuf) was 11.8 +/- 0.4 L/day. Appreciable sieving of IL-1Ra (SC 0.45 +/- 0.10), but not of the other cytokines, was noted (SC TNF alpha, sTNFrI, sTNFrII < 0.09). Despite minimal Kuf of TNF alpha, sTNFrI, and STNFrII (Kuf < 0.8 mL/min), appreciable Kp was noted, suggesting that membrane adsorption occurs (Kp approximately 8 mL/min). There was a nonsignificant increase of the ratios between both TNF receptors and TNF alpha across the filter (sTNFrI/TNF alpha ratio [pre] 231 +/- 37.9 versus [post] 312 +/- 75.3); sTNFrII/TNF alpha ratio [pre] 211 +/- 42.1 versus [post] 291 +/- 79.3). Appreciable Kp of IL-1Ra was noted (Kp 17.3 +/- 1.61 mL/min), which was only in part due to Kuf (4.0 +/- 0.86 mL/min). There was a significant decrease of IL-1Ra levels across the membrane, both overall ([pre] 20.223 +/- 2.282 versus [post] 16.637 +/- 2.039 pg/mL; P < 0.01) and at different time points (P < 0.01). Only for IL-1Ra was significant extraction from plasma noted (ERp 26 +/- 6.0%). Plasma levels of TNF alpha, sTNFrI, sTNFrII, and IL-1Ra were not altered by 24 h of CHF. In conclusion, both cytokines and cytokine inhibitors can be removed from the circulation, either by convective transport or by membrane adsorption. Using low-volume HF (Vuf approximately 12 L/day), no impact on cytokine plasma levels nor the patients hemodynamics or gas exchange was noted. The appreciable SC of IL-1Ra (0.45), however, suggests that HF with high(er) UF volumes (> 50 L/day) may be able to achieve reductions in plasma levels of some peptide (anti)mediators. However, whether this aspecific elimination of both mediators and antimediators may alter the clinical course in critically ill patients remains to be investigated.

Perioperative care: intraoperative fluid balance.

Rational intraoperative fluid therapy is based on an understanding of the pathophysiology of severe trauma and surgery. Fluids of suitable compositions are administered in sufficient quantities to form part of the daily maintenance requirement and also to replace blood and ECF lost during surgery.