Enzyme biomarkers of renal tubular injury in arterial surgery patients.

OBJECTIVE: The aim of this study was to verify whether preoperative diabetes, hypertension, and renal function had any relationship with postoperative tubule function in patients submitted to anesthesia for arterial surgery. METHODS: Prospective observational study. One hundred and forty-four patients submitted to anesthesia for arterial surgery enrolled consecutively and divided into four groups: G1--diabetes and hypertension; G2--diabetes; G3--hypertension; and G4--without hypertension or diabetes. Urine was obtained for laboratory analysis of urinary creatinine (Ucr), alkaline phosphatase (AP), γ-glutamyltransferase (γGT), and blood for cystatin C and creatinine before the surgery (M1) and 24 h after the surgery (M2). RESULTS: Values of γGT, γGT/Ucr, and AP × Î³GT/Ucr increased at M2 in G4. Patients without renal function compromise (GFR ≥90 mL/min/1.73 m(2)) presented increased γGT/Ucr and AP × Î³GT/Ucr values at M2 and those with slightly compromised renal function (60-89 mL/min/1.73 m(2)) presented increased γGT values at M2. There was no correlation between deltaCystatin C and deltaAP, deltaγGT, deltaγGT/Ucr, deltaAP/Ucr, and deltaAP × Î³GT/Ucr. CONCLUSIONS: Diabetes, hypertension, and preoperative renal function seem to interfere in tubular enzymuria immediately after surgery in arteriopathic patients. However, when these markers do not increase in postoperative period, renal dysfunction cannot be discarded.

Does the choice of the halogenated anesthetic influence renal function during hemorrhagic shock and resuscitation?

INTRODUCTION: Halogenated anesthetics can cause changes in the variables that modify the cardiac output necessary to maintain renal hemodynamic during hemorrhagic shock and resuscitation. However, halogenated anesthetics seem to protect against renal ischemia-reperfusion injury. In a model of pressure-guided hemorrhagic shock in dogs, we studied the comparative effects of three halogenated anesthetics-halothane, sevoflurane, and isoflurane-at equipotent concentrations on renal responses after resuscitation. METHODS: Thirty dogs were anesthetized with 1.0 minimum alveolar anesthetic concentration (MAC) of halothane, sevoflurane, or isoflurane. The dogs were splenectomized and hemorrhaged to hold mean arterial pressure at 40-50 mm Hg over 45 min and then resuscitated with the shed blood volume. Hemodynamic variables were measured at baseline, after 45 min of hemorrhage, and 15 and 60 min after resuscitation. Renal variables were measured at baseline and 15 and 60 min after resuscitation. RESULTS: Hemorrhage induced reductions of mean arterial pressure, filling pressures, and cardiac index (p < 0.05), without significant differences among groups (p > 0.05). After 60 min of shed blood replacement, all groups restored hemodynamic and renal variables to the prehemorrhage levels (p > 0.05), without significant differences among groups (p > 0.05), with the exception of sodium fractional excretion, the values for which were significantly higher in isoflurane group, in relation to the other groups after 15 min of re-transfusion (p < 0.05), and renal vascular resistance, the values for which remain lower than baseline in halothane group (p < 0.05). CONCLUSIONS: We conclude that no difference could be detected between choosing equipotent doses of halothane, sevoflurane, or isoflurane in relation to renal variables in dogs submitted to pressure-adjusted hemorrhagic shock and resuscitation.

Effects of a Single Dose of Parecoxib on Inflammatory Response and Ischemic Tubular Injury Caused by Hemorrhagic Shock in Rats.

Parecoxib, a selective COX-2 inhibitor, is used to improve analgesia in postoperative procedures. Here we evaluated whether pretreatment with a single dose of parecoxib affects the function, cell injury, and inflammatory response of the kidney of rats subjected to acute hemorrhage. Inflammatory response was determined according to serum and renal tissue cytokine levels (IL-1α, IL-1ß, IL-6, IL-10, and TNF-α). Forty-four adult Wistar rats anesthetized with sevoflurane were randomized into four groups: placebo/no hemorrhage (Plc/NH); parecoxib/no hemorrhage (Pcx/NH); placebo/hemorrhage (Plc/H); and parecoxib/hemorrhage (Pcx/H). Pcx groups received a single dose of intravenous parecoxib while Plc groups received a single dose of placebo (isotonic saline). Animals in hemorrhage groups underwent bleeding of 30% of blood volume. Renal function and renal histology were then evaluated. Plc/H showed the highest serum levels of cytokines, suggesting that pretreatment with parecoxib reduced the inflammatory response in rats subjected to hemorrhage. No difference in tissue cytokine levels between groups was observed. Plc/H showed higher percentage of tubular dilation and degeneration, indicating that parecoxib inhibited tubular injury resulting from renal hypoperfusion. Our findings indicate that pretreatment with a single dose of parecoxib reduced the inflammatory response and tubular renal injury without altering renal function in rats undergoing acute hemorrhage.

Prognostic factors for perioperative pulmonary events among patients undergoing upper abdominal surgery.

CONTEXT AND OBJECTIVE: The significant relationship between upper abdominal surgery and early (perioperative) pulmonary events was investigated among patients with preoperative pulmonary conditions undergoing general anesthesia. DESIGN AND SETTING: Retrospective study for which data were obtained prospectively from 1999 to 2004, at a tertiary university hospital. METHODS: We retrospectively studied 3107 patients over 11 years old presenting American Society of Anesthesiologists (ASA) status I, II or III who underwent upper abdominal surgery under general anesthesia and were discharged to the recovery room. The preoperative conditions analyzed using logistic regression were: age, sex, ASA physical status, congestive heart failure, asthma, chronic obstructive pulmonary disease (COPD), respiratory failure and smoking. The outcomes or dependent variables included intraoperative and postoperative events: bronchospasm, hypoxemia, hypercapnia, prolonged intubation and airway secretion. RESULTS: Among these patients (1500 males, 1607 females, mean age 48 years, 1088 ASA I, 1402 ASA II and 617 ASA III), there were 80 congestive heart failures, 82 asthmatics, 122 with COPD, 21 respiratory failures and 428 smokers. Logistic regression analysis showed that female sex (p < 0.001), age over 70 years (p < 0.01), smoking (p < 0.001) and COPD (p < 0.02) significantly influenced pulmonary event development, particularly hypoxemia and bronchospasm, at both times but not in the same patients. Asthma and congestive heart failure cases did not present pulmonary events in the recovery room. CONCLUSION: In upper abdominal surgery under general anesthesia, female sex, age over 70, smoking and COPD were independent risk factors for intra and postoperative pulmonary events.

Renal function and histology after acute hemorrhage in rats under dexmedetomidine action.

PURPOSE: About 50 % of indications for dialysis in acute renal failure are related to problems originated during the perioperative period. Intraoperative hemodynamic changes lead to renal vasoconstriction and hypoperfusion. Previous studies have not defined the dexmedetomidine renal role in hemorrhage situations. This study evaluated the effect of dexmedetomidine on renal function and histology after acute hemorrhage in rats. METHODS: Covered study with 20 Wistars rats, anesthetized with sodium pentobarbital, 50 mg.kg(-1), intraperitoneal, randomized into 2 groups submitted to 30% volemia bleeding: DG - iv dexmedetomidine, 3 microg.kg(-1) (10 min) and continuous infusion - 3 microg.kg(-1).h(-1); CG - pentobarbital. For renal clearance estimative, sodium p-aminohippurate and iothalamate were administered. Studied attributes: heart rate, mean arterial pressure, rectal temperature, hematocrit, iothalamate and p-aminohippurate clearance, filtration fraction, renal blood flow, renal vascular resistance, and histological evaluations of the kidneys. RESULTS: DG showed smaller values of heart rate, mean arterial pressure, and renal vascular resistance, but iothalamate clearance and filtration fraction values were higher. There was similarity in p-aminohippurate clearance and renal blood flow. Both groups had histological changes ischemia-like, but dexmedetomidine determined higher tubular dilatation scores. CONCLUSION: In rats, after acute hemorrhage, dexmedetomidine determined better renal function, but higher tubular dilation scores.

Cyclosporine A attenuates apoptosis and necrosis after ischemia-reperfusion-induced renal injury in transiently hyperglycemic rats.

PURPOSE:: To investigate the effects of cyclosporine A on renal ischemia-reperfusion injury during transient hyperglycemia in rats. METHODS:: In a model of ischemia-reperfusion-induced renal injury and transiently induced hyperglycemia by intraperitoneal injection of glucose, 2.5 g.kg-1, Wistar rats were anesthetized with either isoflurane or propofol and received intravenous cyclosporine A, 5 mg.kg-1, five minutes before reperfusion. Comparison groups were isoflurane and propofol sham groups and isoflurane and propofol ischemia-reperfusion-induced renal injury. Renal tubular cell viability was quantitatively assessed by flow cytometry after cell culture and classified as early apoptosis, necrotic cells, and intact cells. RESULTS:: Early apoptosis was significantly higher in isoflurane and propofol anesthetized animals subjected to renal ischemia-reperfusion injury when compared to both cyclosporine A treated and sham groups. Necrosis percentage was significantly higher in propofol-anesthetized animals subjected to renal ischemia-reperfusion injury. The percentage of intact cells was lower in both, isoflurane and propofol anesthetized animals subjected to renal ischemia-reperfusion injury. CONCLUSION:: In a model of ischemia-reperfusion-induced renal injury, cyclosporine A, 5 m.kg-1, administered five minutes before renal reperfusion in rats with acute-induced hyperglycemia under either isoflurano or propofol anesthesia, attenuated early apoptosis and preserved viability in renal tubular cells, regardless of the anesthetic used.

Influence of S(+)-ketamine analgesia in renal intraoperative ischemia: histological study in rats.

PURPOSE: To study in rats the effect of S(+) ketamine on the renal histology after intraoperative hemorrhage. METHODS: Twenty male Wistar rats, anesthetized with sodium pentobarbital, were randomly divided in 2 groups: G1 - control (n=l0) and G2 - S(+)-ketamine (n=10), both submitted to arterial hemorrhage of 30% of volemia in 3 moments (10% each 10 min) 60 min after anesthesia. G2 received S(+)-ketamine, 15 mg. kg-1, i.m., 5 min after anesthesia and 55 min before the 1st hemorrhage moment (Ml). Medium arterial pressure (MAP), rectal temperature (T) and heart rate were monitored. The animals were sacrificed in M4, 30 min after the 3rd hemorrhage moment (M3) and the kidneys and blood collected from hemorrhage were utilized for histological study and hematocrit (Ht) determination. RESULTS: There were significant reduction of MAP, T, and Ht. The histological study verified G1 = G2 for tubular dilation, congestion, and necrosis. The total score addition were significantly different and G2 > G 1. CONCLUSION: Hemorrhage and hypotension determined changes in kidney histology. The rise in catecholamine blood concentration probably was the cause of S(+)-ketamine-induced higher score of histological changes.

Does Spinal Block Through Tattooed Skin Cause Histological Changes in Nervous Tissue and Meninges?: An Experimental Model in Rabbits.

BACKGROUND AND OBJECTIVES: Although there is no documented evidence that tattoo pigments can cause neurological complications, the implications of performing neuraxial anesthesia through tattooed skin are unknown. In this study, we aimed to assess whether spinal puncture performed through tattooed skin of rabbits determines changes over the spinal cord and meninges. In addition, we sought to evaluate the presence of ink fragments entrapped in spinal needles. METHODS: Thirty-six young male adult rabbits, each weighing between 3400 and 3900 g and having a spine length between 38.5 and 39 cm, were divided by lot into 3 groups as follows: GI, spinal puncture through tattooed skin; GII, spinal puncture through tattooed skin and saline injection; and GIII, spinal puncture through skin free of tattoo and saline injection. After intravenous anesthesia with ketamine and xylazine, the subarachnoid space was punctured at S1-S2 under ultrasound guidance with a 22-gauge 2½ Quincke needle. Animals in GII and GIII received 5 µL/cm of spinal length (0.2 mL) of saline intrathecally. In GI, the needle tip was placed into the yellow ligament, and no solution was injected into the intrathecal space; after tattooed skin puncture, 1 mL of saline was injected through the needle over a histological slide to prepare a smear that was dyed by the Giemsa method to enable tissue identification if present. All animals remained in captivity for 21 days under medical observation and were killed by decapitation. The lumbosacral spinal cord portion was removed for histological analysis using hematoxylin-eosin stain. RESULTS: None of the animals had impaired motor function or decreased nociception during the period of clinical observation. None of the animals from the control group (GIII) showed signs of injuries to meninges. In GII, however, 4 animals presented with signs of meningeal injury. The main histological changes observed were focal areas of perivascular lymphoplasmacyte infiltration in the pia mater and arachnoid. There was no signal of injury in neural tissue in any animal of both groups. Tissue coring containing ink pigments was noted in all GI smears from the spinal needles used to puncture the tattooed skin. CONCLUSIONS: On the basis of the present results, intrathecal injection of saline through a needle inserted through tattooed skin is capable of producing histological changes over the meninges of rabbits. Ink fragments were entrapped inside the spinal needles, despite the presence of a stylet.

Do propofol and isoflurane protect the kidney against ischemia/reperfusion injury during transient hyperglycemia?

PURPOSE: To study the effect of isoflurane (Iso) or propofol (Prop) anesthesia on renal ischemia/reperfusion injury (IRI) during transient hyperglycemia. METHODS: Thirty six rats were randomly assigned into six groups of six animals each: PHS (Sham-Prop=1mg.kg-1.min-1 + Hyperglycemia=2.5g.kg-1 of glucose solution administered intraperitoneally); HIS (Sham-Iso + Hyperglycemia); PHI (Prop + Hyperglycemia + Ischemia); IHI (Iso + Hyperglycemia + Ischemia); PI (Prop + Ischemia), and II (Iso + Ischemia). After 30 minutes of anesthesia induction, right nephrectomy was performed (all animals) and the left renal artery was clamped during 25 minutes (ischemia). The animals were sacrificed after 24 hours and blood collection (to dose creatinine) and left kidney removal were performed for histological analysis, and flow cytometry (FCM): percentage of initial apoptosis (APTi) and viable cells (VC). RESULTS: Serum creatinine (mg/dL) was statistically different in groups PHI (3.60±0.40) and IHI (3.23±1.08), p<0.05. Histological analysis was statistically different in groups PHI (4.0[4.0;5.0]) and IHI (4.5[4.0;5.0]), p<0.05. APTi percentage was statistically different in groups PHI (73.2±7.1), and IHI (48.1±14). VC percentage was statistically different in groups PHI (25.8±6.9) and IHI (38.5±9.2), p<0.05. CONCLUSIONS: Propofol and isoflurane showed the same level of protection against ischemia/reperfusion injury in the normoglycemic groups. Transient hyperglycemia is associated with an increase in IRI.

The effect of 6% Hydroxyethyl starch vs. Ringer's lactate on acute kidney injury after renal ischemia in rats.

PURPOSE: To compare fluid replacement therapy with Hydroxyethyl starch 6% (HES) versus Ringer's lactate (RL) in a rodent model of non-septic renal ischemia. METHODS: Forty male Wistar rats were randomized to receive HES 2 ml.kg(-1).hr(-1) or RL 5 ml.kg(-1).hr(-1) that underwent 30 minutes of renal ischemia followed by reperfusion. Twelve hours after kidney ischemia, the kidneys were evaluated for histological changes. Serum NGAL levels were obtained at different times of the experimental protocol. RESULTS: Rodents in the HES group had a median (IQR) grade of renal injury 3 (3 to 5) compared to 2 (2 to 4) in the RL group (p=0.03). NGAL levels were not associated with the severity of kidney injury. CONCLUSION: Hydroxyethyl starch administration caused more kidney injury than Ringer's lactate in a non-infectious model of renal hypoperfusion.

Prevention of renal ischemia/reperfusion injury in rats using acetylcysteine after anesthesia with isoflurane.

PURPOSE: To evaluate the effect of N-acetylcysteine, as a renoprotective agent, when administered early after anesthesia induction, against ischemia/reperfusion injury in rats anesthetized with isoflurane. METHODS: Eighteen male Wistar rats weighing > 300 g were anesthetized with isoflurane. The internal jugular vein and the left carotid artery were dissected and cannulated. The animals were randomly divided into GAcetyl, receiving intravenous N-acetylcysteine, 300 mg/kg, and GIsot, isotonic saline. After 30 minutes, right nephrectomy was performed and the left renal artery was clamped during 45 minutes. The animals were sacrificed after 48 hours and blood samples were taken after anesthetic induction and upon sacrificing of the animals to evaluate blood creatinine. The kidneys were sent for histological analysis. RESULTS: The variation in serum creatinine was 2.33 mg/dL ± 2.21 in GAcetyl and 4.38 mg/dL ± 2.13 in GIsot (p=0.074). Two animals presented intense tubular necrosis in GAcetyl, compared to 5 in GIsot. Only GAcetyl presented animals free of tubular necrosis (two) and tubular degeneration (one). CONCLUSION: After renal ischemia/reperfusion, the rats which were given N-acetylcysteine presented less variation in serum creatinine and milder kidney injuries than the control group.

Renal histology and immunohistochemistry after acute hemorrhage in rats under sevoflurane and ketoprofen effect.

PURPOSE: To investigate the influence of intravenous nonselective cyclooxygenase inhibitor, ketoprofen (keto), on kidney histological changes and kidney cytokines, tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1), levels after hemorrhage of 30% of volemia (three times 10%, intervals of 10 min) in rats. METHODS: Under sevoflurane (sevo) anesthesia, sevo and sevo+keto groups (10 rats each) were instrumented for Ringer solution (5 mL/kg/h) administration and mean arterial pressure (MAP) evaluation, plus keto (1.5mg/kg) administration in sevo+keto group in the beginning of anesthesia. Rectal temperature was continuously measured. The baseline data of temperature and MAP were collected at the first hemorrhage (T1), the third hemorrhage (T2) and 30 min after T2 (T3). Bilateral nephrectomy was achieved for histology and immunohistochemistry. RESULTS: In both groups, temperature and MAP diminished from initial values. Hypothermia was greater in sevo group (p=0.0002). Tubular necrosis was more frequent in sevo group (p=0.02). The studied cytokines were equally present in the kidneys of both groups. CONCLUSION: Ketoprofen was more protective to the rat kidney in condition of anesthesia with sevoflurane and hypovolemia, but it seems that TNF-α and IL-1 were not involved in that protection.

Cyclosporine A attenuates apoptosis and necrosis after ischemia-reperfusion-induced renal injury in transiently hyperglycemic rats

Abstract Purpose: To investigate the effects of cyclosporine A on renal ischemia-reperfusion injury during transient hyperglycemia in rats. Methods: In a model of ischemia-reperfusion-induced renal injury and transiently induced hyperglycemia by intraperitoneal injection of glucose, 2.5 g.kg-1, Wistar rats were anesthetized with either isoflurane or propofol and received intravenous cyclosporine A, 5 mg.kg-1, five minutes before reperfusion. Comparison groups were isoflurane and propofol sham groups and isoflurane and propofol ischemia-reperfusion-induced renal injury. Renal tubular cell viability was quantitatively assessed by flow cytometry after cell culture and classified as early apoptosis, necrotic cells, and intact cells. Results: Early apoptosis was significantly higher in isoflurane and propofol anesthetized animals subjected to renal ischemia-reperfusion injury when compared to both cyclosporine A treated and sham groups. Necrosis percentage was significantly higher in propofol-anesthetized animals subjected to renal ischemia-reperfusion injury. The percentage of intact cells was lower in both, isoflurane and propofol anesthetized animals subjected to renal ischemia-reperfusion injury. Conclusion: In a model of ischemia-reperfusion-induced renal injury, cyclosporine A, 5 m.kg-1, administered five minutes before renal reperfusion in rats with acute-induced hyperglycemia under either isoflurano or propofol anesthesia, attenuated early apoptosis and preserved viability in renal tubular cells, regardless of the anesthetic used.

Dexmedetomidine and S(+)-ketamine in ischemia and reperfusion injury in the rat kidney.

PURPOSE: To investigate blood creatinine and renal histology in rats anesthetized with S(+)-ketamine (keta) or dexmedetomidine (dex) and submitted to kidney ischemia/reperfusion injury (IRI). METHODS: Under intraperitoneal (ip) S(+)-ketamine, 20 male Wistar rats were divided into two groups (n=10): maintenance with iv S(+)-ketamine or dex (keta and dex groups), and submitted to right (R) nephrectomy and left (L) renal artery clamping for 45 min. Blood creatinine was measured before ischemia (T1) and 48h after reperfusion (T2), when L nephrectomy was performed. Histological analysis was performed in all kidneys. RESULTS: Blood creatinine was significantly higher at T2 in both groups, but dex group results were lower than those of keta group. Histological changes: between groups, R kidneys did not differ; there were significant high scores for vascular dilation: keta L kidneys; for vascular congestion, tubular dilation, and necrosis: L kidneys from both groups; for tubular degeneration: keta R kidneys. CONCLUSION: S(+)-ketamine plus IRI were aggressive to rat kidneys, according to histological changes, and dexmedetomidine may have not totally protected the kidneys from these injuries, despite the better results of blood creatinine.

Clinical evaluation of two Ke0 in the same pharmacokinetic propofol model: study on loss and recovery of consciousness.

BACKGROUND AND OBJECTIVE: The constant equilibrium between the plasma and effect site (ke0) is used by pharmacokinetic models to calculate a drug concentration in its site of action (Ce). It would be interesting if Ce of propofol was similar at loss and recovery of consciousness. The objective of this study was to evaluate the clinical performance of two different ke0 (fast = 1.21 min(-1), and slow = 0.26 min(-1)) in relation to Ce during loss and recovery of consciousness using Marsh pharmacokinetic model. METHODS: Twenty healthy adult male volunteers participated in this study. In all volunteers propofol was administered as target-controlled infusion, Marsh pharmacokinetic model for fast ke0 and, at a different time, the same pharmacokinetic model with slow ke0 was used. Initially, propofol was infused with a serum target-controlled infusion of 3.0 µg.mL(-1). Loss of consciousness and recovery of consciousness were based on response to verbal stimulus. Ce was recorded at the moment of loss and recovery of consciousness. RESULTS: On loss and recovery of consciousness, the Ce for fast ke0 was different (3.64 ± 0.78 and 1.47 ± 0.29 µg.mL(-1), respectively, p < 0.0001), while with slow ke0 the Ce was similar (2.20 ± 0.70 and 2.14 ± 0.43 µg.mL(-1), respectively, p = 0.5425). CONCLUSIONS: Clinically, the slow ke0 (0.26 min(-1)) incorporated in the Marsh pharmacokinetic model showed better performance than the fast ke0 (1.21 min(-1)), since the calculated concentration of propofol at the effect site on loss and recovery of consciousness was similar.

Retrospective analysis of risk factors and predictors of intraoperative complications in neuraxial blocks at Faculdade de Medicina de Botucatu-UNESP.

BACKGROUND AND OBJECTIVES: Cardiovascular changes associated with neuraxial blocks are a cause of concern due to their frequency and because some of them can be considered physiological effects triggered by the sympathetic nervous system blockade. The objective of this study was to evaluate intraoperative cardiovascular complications and predictive factors associated with neuraxial blocks in patients ≥ 18 years of age undergoing non-obstetric procedures over an 18-year period in a tertiary university hospital--HCFMB-UNESP. METHODS: A retrospective analysis of the following complications was undertaken: hypertension, hypotension, sinus bradycardia, and sinus tachycardia. These complications were correlated with anesthetic technique, physical status (ASA), age, gender, and preoperative co-morbidities. The Tukey test for comparisons among proportions and logistic regression was used for statistical analysis. RESULTS: 32,554 patients underwent neuraxial blocks. Intraoperative complications mentioned included hypotension (n=4,109), sinus bradycardia (n=1,107), sinus tachycardia (n=601), and hypertension (n=466). Hypotension was seen more often in patients undergoing continuous subarachnoid anesthesia (29.4%, OR=2.39), ≥ 61 years of age, and female (OR=1.27). CONCLUSIONS: Intraoperative hypotension and bradycardia were the complications observed more often. Hypotension was related to anesthetic technique (CSA), increased age, and female. Tachycardia and hypertension may not have been directly related to neuraxial blocks.

Cystatin C and glomerular filtration rate in the cardiac surgery with cardiopulmonary bypass.

OBJECTIVE: The aim of this study was to compare cystatin C versus creatinine as a marker for acute kidney injury in patients submitted to cardiac surgery with cardiopulmonary bypass. METHODS: Fifty consecutive patients submitted to coronary artery bypass grafting were studied. Renal function was evaluated by serum cystatin C and creatinine. Blood samples were obtained from each patient at three time points: before operation, and on the first and fifth postoperative days. Glomerular filtration rate (GFR) was calculated by Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), and Larsson (Cys-GFR) formulas. RESULTS: Creatinine and GFR by CG and MDRD formulas did not show statistical difference between study times. After renal injury from surgery, there was an increase in cystatin C on the 1st and 5th day after surgery, being significantly different on the 5th postoperative (P<0.01). The GFR by Larson formula was higher in the preoperative time (105.2 +/- 41.0 ml/min) than in the 5th postoperative day (89.5+/- 31.5 ml/min; P<0.012). CONCLUSION: The cystatin C and the Cys-GFR showed significant changes after cardiac surgery when compared with the creatinine and respective GFR calculated by the Cockcroft-Gault and MDRD formulas.

Does propofol and isoflurane protect the kidney against ischemia/reperfusion injury during transient hyperglycemia?

PURPOSE: To study the effect of isoflurane (Iso) or propofol (Prop) anesthesia on renal ischemia/reperfusion injury (IRI) during transient hyperglycemia. METHODS: Thirty six rats were randomly assigned into six groups of six animals each: PHS (Sham-Prop=1mg.kg-1.min-1 + Hyperglycemia=2.5g.kg-1 of glucose solution administered intraperitoneally); HIS (Sham-Iso + Hyperglycemia); PHI (Prop + Hyperglycemia + Ischemia); IHI (Iso + Hyperglycemia + Ischemia); PI (Prop + Ischemia), and II (Iso + Ischemia). After 30 minutes of anesthesia induction, right nephrectomy was performed (all animals) and the left renal artery was clamped during 25 minutes (ischemia). The animals were sacrificed after 24 hours and blood collection (to dose creatinine) and left kidney removal were performed for histological analysis, and flow cytometry (FCM): percentage of initial apoptosis (APTi) and viable cells (VC). RESULTS: Serum creatinine (mg/dL) was statistically different in groups PHI (3.60±0.40) and IHI (3.23±1.08), p<0.05. Histological analysis was statistically different in groups PHI (4.0[4.0;5.0]) and IHI (4.5[4.0;5.0]), p<0.05. APTi percentage was statistically different in groups PHI (73.2±7.1), and IHI (48.1±14). VC percentage was statistically different in groups PHI (25.8±6.9) and IHI (38.5±9.2), p<0.05. CONCLUSIONS: Propofol and isoflurane showed the same level of protection against ischemia/reperfusion injury in the normoglycemic groups. Transient hyperglycemia is associated with an increase in IRI.

The effect of 6% Hydroxyethyl starch vs. Ringer's lactate on acute kidney injury after renal ischemia in rats

PURPOSE: To compare fluid replacement therapy with Hydroxyethyl starch 6% (HES) versus Ringer's lactate (RL) in a rodent model of non-septic renal ischemia. METHODS: Forty male Wistar rats were randomized to receive HES 2 ml.kg-1.hr-1or RL 5 ml. kg-1.hr-1 that underwent 30 minutes of renal ischemia followed by reperfusion. Twelve hours after kidney ischemia, the kidneys were evaluated for histological changes. Serum NGAL levels were obtained at different times of the experimental protocol. RESULTS: Rodents in the HES group had a median (IQR) grade of renal injury 3 (3 to 5) compared to 2 (2 to 4) in the RL group (p=0.03). NGAL levels were not associated with the severity of kidney injury. CONCLUSION: Hydroxyethyl starch administration caused more kidney injury than Ringer's lactate in a non-infectious model of renal hypoperfusion.

Prevention of renal ischemia/reperfusion injury in rats using acetylcysteine after anesthesia with isoflurane / Prevenção de lesão de isquemia/reperfusão em ratos com acetilcisteína após anestesia com isoflurano

PURPOSE: To evaluate the effect of N-acetylcysteine, as a renoprotective agent, when administered early after anesthesia induction, against ischemia/reperfusion injury in rats anesthetized with isoflurane. METHODS: Eighteen male Wistar rats weighing > 300g were anesthetized with isoflurane. The internal jugular vein and the left carotid artery were dissected and cannulated. The animals were randomly divided into GAcetyl, receiving intravenous N-acetylcysteine, 300mg/kg, and GIsot, isotonic saline. After 30 minutes, right nephrectomy was performed and the left renal artery was clamped during 45 minutes. The animals were sacrificed after 48 hours and blood samples were taken after anesthetic induction and upon sacrificing of the animals to evaluate blood creatinine. The kidneys were sent for histological analysis. RESULTS: The variation in serum creatinine was 2.33mg/dL ± 2.21 in GAcetyl and 4.38mg/dL ± 2.13 in GIsot (p=0.074). Two animals presented intense tubular necrosis in GAcetyl, compared to 5 in GIsot. Only GAcetyl presented animals free of tubular necrosis (two) and tubular degeneration (one). CONCLUSION: After renal ischemia/reperfusion, the rats which were given N-acetylcysteine presented less variation in serum creatinine and milder kidney injuries than the control group.

OBJETIVO: Avaliar o efeito da N-acetilcisteína na proteção renal contra lesão de isquemia/reperfusão, quando administrada logo após a indução anestésica, em ratos anestesiados com isoflurano. MÉTODOS: Dezoito ratos Wistar machos pesando mais que 300g foram anestesiados com isoflurano. A jugular interna direita e a carótida esquerda foram dissecadas e canuladas. Os animais foram distribuídos aleatoriamente em GAcetil, recebendo N-acetilcisteína por via intravenosa, 300mg/kg, e GIsot, solução salina. Foi realizada nefrectomia direita e clampeamento da artéria renal esquerda por 45 min. Os animais foram sacrificados após 48h, sendo colhidas amostras sanguíneas após a indução anestésica e ao sacrifício dos mesmos para avaliar a creatinina sérica. Realizou-se histologia renal. RESULTADOS: A variação da creatinina foi 2,33mg/dL ± 2,21 no GAcetil e 4,38mg/dL ± 2,13 no GIsot (p=0,074). Dois animais apresentaram necrose tubular intensa no GAcetil, comparados a cinco no GIsot. Apenas GAcetil apresentou animais livres de necrose tubular (dois) e degeneração tubular (um). CONCLUSÃO: Após isquemia/reperfusão renais, os ratos aos quais se administrou N-acetilcisteína apresentaram menor variação na creatinina sérica e lesões renais mais leves que o grupo controle.