Applications and outcome of hemodialysis in cats: a review of 29 cases

Hemodialysis (HD) has been used in the management of renal failure in dogs, but its feasibility has not been reported for uremic cats. Therefore, we investigated the technical possibility, efficacy, and complications of intermittent HD in cats with severe uremia. A total of 160 HD treatments were performed on 29 cats with acute renal failure (ARF) (n = 15), chronic renal failure (CRF) (n = 6), or acute on CRF (n = 8) between November 1993 and June 1996. Hemodialysis treatments were performed with transcutaneous dialysis catheters using a bicarbonate-based delivery system, sodium modeling, and volumetric-controlled ultrafiltration. Presenting serum chemistries (mean +/- SD) for all cats were creatinine, 16.4 +/- 7.5 mg/dL; blood urea nitrogen (BUN), 229 +/- 87 mg/dL; phosphate, 15.4 +/- 5.4 mg/dL; potassium, 6.0 +/- 1.6 mEq/L; and HCO3-, 16.0 +/- 4.4 mEq/L. For intensive HD treatments, pre-HD versus post-HD creatinine changed from 10.3 +/- 4.4 to 1.6 +/- 0.9 mg/dL and BUN from 105 +/- 33 to 8 +/- 10 mg/dL. One or more adverse events occurred during 111 (69%) treatments. Dialysis-related events included hypotension, dialysis dysequilibrium, clotting, and bleeding. Nine of 15 (60%) cats with ARF and 1 cat with CRF recovered sufficiently to survive without ongoing need for HD. For the remaining cats, the proximate causes of death were dialysis related in 9 cats, uremia related in 6 cats, and iatrogenic or unknown in 4 cats. Hemodialysis is technically feasible and effectively controls the biochemical disturbances of uremic cats. It is especially valuable for the management of severe ARF, permitting recovery in a large number of cats refractory to conventional therapy. Technical complications and chronic debility, however, may limit its usefulness for cats with advanced CRF.     

Clinical survey of congenital cytomegalovirus infection in Japan

Contrast media-induced nephropathy is one of the leading causes of hospital-acquired renal failure, occurring most frequently in patients with pre-existing renal insufficiency. We prospectively studied 55 patients with chronic renal insufficiency (serum creatinine concentration 1.4 to 3.5 mg/dl) who underwent abdominal aortography and arteriography of the lower extremities. The patients were randomized into two groups. Group 1, 28 patients, received dopamine 2.5 mcg/kg beginning 1 hour before arteriography and continuing for 12 hours. Group 2 received an equal volume of saline for the same period of time. Serum creatinine and 12-hour creatinine clearance were measured before arteriography and for 4 consecutive days afterward. Acute contrast-induced decrease in renal function was defined as increase in the baseline serum creatinine concentration > or = 0.5 mg/dl. On day 1 postarteriography the serum creatinine increased from baseline .193 mg/dl for controls while the dopamine group decreased slightly from baseline .018 mg/dl (p = 0.002). Excepting day 1 postarteriography, there was no statistical difference between groups, and serum levels for both groups increased linearly from baseline across time (dopamine p = 0.028, control p = 0.025). In patients with pre-arteriography baseline serum levels greater than or equal to 2.0 mg/dl, however, the increase in serum creatinine from baseline levels was consistently and significantly greater in the control group through the fourth day (0.012 < or = p < or = 0.049). Creatinine clearance did not change significantly from baseline after arteriography in the dopamine group (baseline versus days 1 through 4, 0.238 < or = p < or = 0.968); however, the control group showed a significant linear decrease in creatinine clearance from baseline through the fourth day after arteriography (p = 0.016). Dopamine infusion prevented a rise in serum creatinine 24 hours after angiography in patients with pre-existing renal insufficiency, and protected against contrast-induced decrease in renal function in patients whose baseline serum creatinine was > or = 2.0 mg/dl.     

Analysis of growth in five-sixths-nephrectomized rats

The present study was designed in an attempt to better define the pattern of growth in five-sixths-nephrectomized rats. Male Sprague-Dawley rats underwent two-stage (days 0 and 7) five-sixths nephrectomy (NX, n = 16) or sham surgery (SHAM, n = 9). At the time of sacrifice (day 21), renal failure (CRF) of NX rats was confirmed by elevated (p < or = 0.0001) serum concentrations (X +/- SEM) of urea nitrogen (SUN) (56 +/- 5 vs. 20 +/- 1 mg/dl) and creatinine (0.7 +/- 0.04 vs. 0.4 +/- 0.02 mg/dl) and reduced SUN (0.13 +/- 0.02 vs. 0.44 +/- 0.05 ml/min/100 g) and creatinine clearances (0.23 +/- 0.02 vs. 0.58 +/- 0.05 ml/min/100 g). As shown by lower cumulative gains of weight (41 +/- 6 vs. 74 +/- 4 g) and length (5.0 +/- 0.4 vs. 6.8 +/- 0.3 cm), NX rats grew subnormally. Detailed analysis of growth data revealed: (1) In spite of being identically matched in weight and length on day 0, at day 7, NX rats already weighed less than SHAM animals (147.1 +/- 2.3 vs. 153.4 +/- 1.9 g, p = 0.03). (2) From day 7 on, daily gain of weight was lower in the NX group only on days 8 (-6.08 +/- 0.52 vs. -1.60 +/- 0.69 g/100 g body weight) and 9 (-0.41 +/- 1.73 vs. 5.18 +/- 0.63 g/100 g body weight). (3) Following the early post-second-nephrectomy period, two subgroups of NX rats were clearly differentiated according to whether or not their daily growth rate was lower than that of SHAM animals. Maintained subnormal growth rate was observed in rats with severe CRF (SUN 73 +/- 5 mg/dl, range 54-90) but not in rats having milder uremia (42 +/- 3 mg/dl, range 31-51). Thus, growth in five-sixths-nephrectomized rats should be reported based on daily weight increments (g/100 g body weight). Subnormal growth can be attributed to CRF provided SUN is at least 3 times as high as normal while growth impairment of rats with less marked reduction of renal function is likely related to transient acute renal failure and postsurgical catabolic state.     

Quantification of creatinine kinetic parameters in patients with acute renal failure

BACKGROUND: Urea kinetic modeling (UKM) and creatinine (Cr) kinetic modeling (CKM) are used in the nutritional evaluation of end-stage renal disease (ESRD) patients. Both the UKM-derived normalized protein catabolic rate (nPCR) and the CKM-derived estimate of lean body mass (LBM) may also provide important information in critically ill acute renal failure (ARF) patients. Estimation of LBM may be particularly useful as previous data demonstrate that malnutrition adversely influences outcome in ARF patients. METHODS: Eleven critically ill ARF patients (age 52 +/- 21 years; mean +/- SD) treated with continuous venovenous hemofiltration (CVVH) were the study group. They were analyzed at steady state with a single-pool variable-volume model that determined the creatinine generation rate (GCr) by a methodology that we have previously described. RESULTS: The CVVH ultrafiltrate production rate was 913 +/- 49 ml/hr, yielding a blood Cr clearance of 15.2 +/- 0.9 ml/min and a steady state serum Cr of 3.4 +/- 1.7 mg/dl. Daily creatinine generation normalized to body wt (creatinine index: CI) was 6.3 +/- 0.8 and 10.6 +/- 3.0 mg/kg/day for females (N = 4) and males (N = 7), respectively (P < 0.05). Estimated mean LBM was 30.0 +/- 2.0 and 41.2 +/- 7.0 kg in females and males, respectively (P < 0.05), while the same parameter normalized to body wt was 0.50 +/- 0.05 and 0.52 +/- 0.10, respectively. These values are substantially lower than those previously reported for both normal and ESRD patients. Regression analysis demonstrated both GCr (r2 = 0.96; P < 0.001) and LBM (r2 = 0.96; P < 0.001) were significantly correlated with steady state serum Cr in a linear manner. However, no significant correlation (r2 = 0.06; P = 0.24) between nPCR and CI was observed. CONCLUSIONS: These data suggest critically ill ARF patients have severe somatic protein depletion. This malnourished state is likely due to deficits established prior to the development of ARF, such as those secondary to underlying chronic illnesses or prolonged hospitalization, and deficits related to acute hypercatabolism. Quantitative assessment of malnutrition in ARF patients with this CKM-based methodology may permit a better understanding of predisposing factors and, consequently, facilitate the development of interventions designed to prevent malnutrition in these patients.     

Renal failure after open heart surgery

One hundred fifty of 490 patients undergoing open heart surgery had renal failure attributable to cardiopulmonary bypass. In 69, serum creatinine concentrations did not exceed 2 mg/dl and returned to normal by the fourth postoperative day. In 60 patients, serum creatinine attained levels between 2 and 5 mg/dl, oliguria did not develop, and recovery of renal function occurred within 4 to 37 days. Serum creatinine increased to levels exceeding 5 mg/dl in 21 patients, 11 of whom were oliguric. Despite dialysis, 14 of these patients died from cardiac causes or sepsis. Prolonged cardiopulmonary bypass time, hypotension, oliguria, low output syndrome, and hemoglobinemia during open heart surgery correlated with the development of renal failure postoperatively. Although severe renal failure was an uncommon complication after open heart surgery, its occurrence carried a grave prognosis.     

Long-term effect of lovastatin on lipoprotein profile in patients with primary nephrotic syndrome

Eight patients with biopsy-proven primary nephrotic syndrome were included in an open, prospective, two-year study of lovastatin. One patients was withdrawn after 6 months due to an asymptomatic rise in creatinine phosphokinase, which was rapidly reversed after interruption of lovastatin. In the remaining patients, treatment was well-tolerated and produced no side effects. After 2 years of treatment, these 7 patients had decreases in total cholesterol from 446 +/- 165 to 250 +/- 57 mg/dl (p < 0.001), LDL cholesterol from 343 +/- 121 to 174 +/- 49 mg/dl (p < 0.001), Apo B lipoprotein from 162 +/- 60 to 108 +/- 42 mg/dl (p < 0.05), triglycerides from 336 +/- 273 to 182 +/- 71 mg/dl (p < 0.04). There was no change in HDL cholesterol. The LDL/HDL cholesterol and the total/HDL cholesterol ratios fell from 15.0 +/- 12.1 and 19.1 +/- 17.2 mg/dl before the study to 4.4 +/- 1.2 and 6.3 +/- 1.6 mg/dl, respectively, at 2 years. A decrease in proteinuria from 8.6 +/- 4.6 to 5.0 +/- 3.7 g/24 h (p < 0.02) was noted in 4 patients on concomitant ACE inhibitor therapy. Renal function remained stable in all patients throughout the study, except for one whose moderate impairment progressed to end-stage renal failure requiring dialysis 3 months poststudy. We conclude that long-term lovastatin in patients with primary nephrotic syndrome is an effective and generally safe treatment for accompanying dyslipidemia.     

Protection afforded by a novel K channel opener (Y-26763), against glycerol-induced acute renal failure (ARF) in rats

Y-26763, a benzopyran derivative, is a newly developed ATp-sensitive K channel opener and has been reported to protect against ischemic acute renal failure (ARF). We examined the effects of Y-26763 on glycerol-induced myoglobinuric ARF in the rats. ARf was induced in 28 adult male Sprague-Dawley rats by hind-limb intramuscular injection of 50% glycerol (5 ml/kg) after 18 hrs of water deprivation. Y-26763, 7 micrograms/kg (GY group, n = 10) of vehicle (G group, n = 12) was given intravenously 15 min before glycerol injection. Glibenclamide (20 mg/kg), a K channel blocker was given prior to Y-26763 injection to see of the effects was due to the K-channel opener (GYG group, n = 6). Animals were sacrificed 24 or 96 hrs after glycerol injection. Y-26763 partially, but significantly, restored renal dysfunction 24 hrs after ARF. Pcr (mg/dl) and Ccr (ml/min), respectively were as follows: G group, 5.7 +/- 0.4, 0.015 +/- 0.006; GY group, 4.1 +/- 0.4, 0.061 +/- 0.027 (p < 0.05). These favorable effects were antagonized by glibenclamide (Pcr in GYG group, 5.4 +/- 0.3 mg/dl, p < 0.05). Renal calcium content was not statistically significant (3.5 +/- 1.2 vs. 3.4 +/- 1.2 micrograms/mg dry weight). Histological examinations revealed that extensive tubular necrosis and cast formation seen in the G group were reduced in the GY group. At the recovery phase, 96 hrs after glycerol injection, Y-26763 accelerated the recovery from ARF as shown in Pcr (mg/dl) and Ccr (ml/min): 4.3 +/- 0.2, 0.05 +/- 0.01 in the G group, 2.8 +/- 0.2, 0.13 +/- 0.02) in the GY group (p < 0.01). In conclusion, Y-26763 partially protected against glycerol-induced ARF.     

Lipoproteins and lipid peroxidation abnormalities in patients with chronic renal disease

Increasing experimental and clinical evidence suggests that lipoproteins and lipid peroxidation can be important modulators in progressive kidney disease. A group of 54 patients with varying degrees of kidney impairment was studied to find the abnormalities in lipoproteins and lipid peroxidation. Lipoproteins and lipid peroxidation products, malondialdehyde (MDA) were measured in the plasma of 54 chronic renal disease patients CGN 33, nephrosclerosis 11, 7CTIN, 1PCKD, unknown 2 and compared with values obtained from 32 healthy controls. The patients were divided into 5 groups according to serum creatinine levels: Group 1 (serum creatinine of 2 mg/dl), group 2 (S. creatinine > 2-4 mg/dl), group 3 (S. creatinine > 4-8 mg/ dl), group 4 (S. creatinine > 8-12 mg/dl), group 5 (S. creatinine > 12 mg/dl). Plasma cholesterol was higher significantly than controls in patients with group 1, 2 and 3 (p < 0.01, < 0.001, < 0.05) respectively while plasma LDL-chol was statistically significantly different from controls only in group 2 patients (p < 0.001). Plasma VLDL-chol, beta-VLDL-chol, triglycerides, ratio of chol/HDL and LDL/ HDL showed high levels in all groups compared with controls but more evident in patients of group 2. Plasma HDL-chol decreased during the progression of renal failure. All groups had significantly elevated plasma malonyldialdehyde (MDA) vs controls (p < 0.001), especially highest value was found in group 2. Triglycerides, beta-VLDL chol, VLDL-chol LDL/HDL, chol/HDL correlated very closely with plasma MDA levels and also with serum creatinine. Patients with chronic renal disease showed lipoprotein abnormalities and accelerated lipid peroxidation. The evidence was more marked in patients with normal to mild renal insufficiency which suggested the role of oxidative stress early in the course of nephron injury.     

Interobserver variability in recognizing arousal in respiratory sleep disorders

BACKGROUND: The study was designed to investigate the influence of haemodialysis on the pharmacokinetics of the non-ionic contrast medium iopentol and the outcome of radiocontrast nephropathy in patients at risk undergoing angiography. METHODS: We prospectively studied 30 patients with reduced renal function (mean serum creatinine concentration (+/- SEM), 2.4 +/- 0.16 mg/dl (212 +/- 14 mumol/l)). Patients were randomly assigned to receive either a haemodialysis procedure for 3 h, started as soon as possible (63 +/- 6 min) after administration of contrast medium, or a conservative treatment. Serum concentrations of iopentol and creatinine were followed for up to 14 days. RESULTS: The extracorporal plasma clearance of contrast medium was 71 +/- 2.5 ml/min. The fraction of the dose eliminated was 32 +/- 3%. The rate of radiocontrast nephropathy (defined as serum creatinine increase of > or = 0.5 mg/dl (44 mumol/l) within 48 h) after administration of contrast medium was similar in both groups (53 and 40% in group 1 (haemodialysis) and group 2 (conservative treatment) respectively). The course of absolute changes in serum creatinine over the whole observation period was not different in both groups. CONCLUSIONS: The data indicate that haemodialysis eliminates contrast medium effectively, but it may not influence the incidence or outcome of contrast induced nephropathy.     

Botulinum toxin as an adjunct for the treatment of acute anteromedial arytenoid dislocation

Serum creatinine, a surrogate for both renal function and homocysteine generation, is an important determinant of fasting plasma total homocysteine levels in stable renal transplant recipients. In this study, it is hypothesized that among stable renal transplant recipients with normal creatinine levels (i.e., < or = 1.5 mg/dl), serum cystatin C, a more sensitive indicator of GFR, would better predict fasting total homocysteine levels compared with serum creatinine. Fasting plasma total homocysteine, folate, vitamin B12, and pyridoxal 5'-phosphate levels, along with serum cystatin C, creatinine, and albumin levels, were determined in 28 consecutive renal transplant recipients (mean age 47 +/- 14 yr; 60.7% men) with stable allograft function, whose serum creatinine was < or = 1.5 mg/dl. General linear modeling with analysis of covariance revealed that serum cystatin C was independently predictive (partial R = 0.494; P = 0.023) of fasting total homocysteine levels after adjustment for age, gender, vitamin status, albumin, and creatinine levels. In contrast, creatinine levels were not predictive of fasting total homocysteine levels in this model (P = 0.110) or an identical model that excluded cystatin C (P = 0.131). Serum cystatin C levels may reflect subtle decreases in renal function that independently predict fasting total homocysteine levels among stable renal transplant recipients with a normal serum creatinine.     

Renal proximal disfunction based on activity of n-acetyl-beta-d-glucosaminidase in urine of patients with kidney failure

N-acetyl-beta-D-glucosaminidase (NAG) urine activities of 63 patients with stable and unstable chronic renal failure have been investigated. The values of NAG activity obtained from these patients were compared with NAG activity of 33 normal controls. Abnormal NAG values (> 70 nmol/mg of creatinine) were found in 60 (95.2%) patients with chronic renal failure and the median of all values was 327.8 nmol/mg of creatinine. It was 14-fold greater than the median of values for normal controls. There were any significant differences of NAG values between the patients with massive proteinuria (> 1.5 g/24 h), moderate proteinuria and those without 24 hour proteinuria or non-significant proteinuria (respectively 423.5 +/- 286.3 vs 414.4 +/- 334.8 vs 453.0 +/- 451.3 nmol/mg of creatinine). There was no significant difference between the two subgroups of patients with NAG values above and below 280 nmol/mg of creatinine in age, gender, serum urea and uric acid levels. However, the incidence of patients with NAG values higher than 280 nmol/mg of creatinine was statistically significant in unstable course of renal insufficiency and raised serum creatinine levels. It is suggested that the measurement of NAG excretion may be helpful to monitor unstable process in renal failure.     

Endothelial cell dysfunction in patients with impaired renal function

In order to investigate endothelial cell dysfunction in patients with impaired renal function, we measured circulating endothelin (ET-1) and thrombomodulin (Tm) concentrations used as markers for endothelial cell injury in patients with renal failure. 1) ET-1 and Tm were significantly higher in patients with renal failure and pre-dialysis patients than in normal subjects. Tm in CRF patients was significantly greater than that in ARF patients. In contrast, ET-1 was significantly greater in ARF than in CRF. 2) A positive correlation was found between serum creatinine concentration (Cr) and Tm in pre-dialysis patients. However, no correlation was found between Cr and ET-1. 3) A positive correlation was found between Tm and the duration of dialysis in HD patients, but not in CAPD patients. 4) With the improvement of renal function after regular HD treatment, a substantial reduction was found in ARF patients in both Tm and ET-1, but not in CRF patients. The present study suggests the presence of endothelial cell dysfunction in patients with impaired renal function. The progression of endothelial cell damage may differ between patients on HD and those on CAPD. In addition, it is suggested that endothelial cell dysfunction reverses in ARF patients with improved renal function.     

Serum immunoreactive leptin concentration and its relation to the body fat content in chronic renal failure

Leptin, secreted from fat cells, functions as a lipostat mechanism through modulation of satiety signals. The role of leptin in humans has been only partly revealed. However, obese patients have markedly elevated levels of this hormone, and in both normal-weight and obese subjects there is a direct correlation between serum leptin levels and the percentage of body fat. The aim of the present study was to investigate the role of leptin and its relation to body fat content in chronic renal failure (CRF), a disorder associated with decreased appetite. Serum leptin levels and body composition (dual-energy x-ray absorptiometry) were measured in a cohort of 59 patients with terminal CRF (creatinine clearance rate, 8 +/- 1 ml/min). Sixteen of the patients were re-evaluated after 12 mo of peritoneal dialysis treatment, and eight patients were re-evaluated after 12 mo of hemodialysis treatment. The mean serum leptin concentrations were markedly higher (mean +/- SEM) in patients with CRF than in healthy control subjects matched for gender and body mass index (25.7 +/- 5.2 ng/ml versus 8.4 +/- 0.9 ng/ml; P < 0.001). Patients with ongoing signs of inflammation (C-reactive protein > 10 mg/L) demonstrated higher serum leptin levels (41.9 +/- 13.7 ng/ml versus 18.6 +/- 4.2 ng/ml; P < 0.05) than patients with normal C-reactive protein. A strong positive correlation (rho = 0.83; P < 0.0001) was found between serum leptin concentrations and the percentage of body fat. After 12 mo of peritoneal dialysis, the amount of body fat increased markedly (19.0 +/- 1.5 to 25.1 +/- 2.2 kg; P < 0.001), and the changes in serum leptin concentrations correlated significantly (rho = 0.69; P < 0.01) to the changes in the body fat content. In contrast, no significant changes in either body fat content or serum leptin levels were recorded in the eight patients that were re-evaluated after 12 mo of hemodialysis. Serum leptin concentrations are approximately three times higher in patients with CRF compared with healthy control subjects with a similar body mass index. In this study, it is also demonstrated that serum leptin is a good marker for the body fat content in CRF patients and correlates strongly to changes in body fat during 12 mo of peritoneal dialysis. These findings suggest that serum leptin could serve as a valuable clinical marker for the body fat content in patients with CRF. Further studies are needed to verify the hypothesis that increased serum leptin concentrations may contribute to uremic anorexia.     

Exogenous interleukin-3 enhances IL-4 production by splenic CD4+ cells during the early stages of a Trichinella spiralis infection

We determined serum advanced glycation end-products (AGE) levels in patients with NIDDM and evaluated the relationship between these levels and diabetic complications. The subjects consisted of 125 patients (mean age, 59.2 +/- 11.1 years, duration of diabetes 11.6 +/- 8.9 years, mean HbA1c, 6.8 +/- 1.0%) with stable blood sugar control. Sixty-three healthy volunteers (mean age, 58.3 +/- 12.7 years) served as controls. Serum AGE were measured by a newly developed ELISA method. Serum AGE levels were significantly higher in the diabetic group compared with the normal control group (7.2 +/- 14.6 vs. 3.3 +/- 1.0 mU/ml, P < 0.05). Significant correlations were seen between serum AGE and the degree of diabetic nephropathy. Serum AGE levels of diabetic patients with proliferative retinopathy were significantly higher than those of patients without proliferative retinopathy (5.7 +/- 1.8 vs. 3.1 +/- 1.0 mU/ml, P < 0.025) in the patient groups whose serum creatinine levels were between 2.0 and 3.9 mg/dl, although serum creatinine levels of both groups were not significantly different. Serum AGE levels reflected the severity of diabetic complications, including nephropathy and retinopathy.     

Low leptin gene expression and hyperleptinemia in chronic renal failure

BACKGROUND: The ob gene product leptin is thought to be a key regulator of food intake and body weight. Patients having advanced chronic renal failure (CRF) have markedly higher serum leptin levels. It is not known whether the increase in leptin levels in CRF is caused by a decreased plasma clearance and/or increased production. METHODS: In the present study serum leptin levels and glomerular filtration rate (GFR) were measured in 219 patients having various degrees of renal failure. In addition, serum leptin levels, C-reactive protein (CRP), body composition (by dual-energy x-ray absorptiometry) and ob gene expression (by in situ hybridization histochemistry) were determined in 15 patients with advanced CRF. Seven of the patients were re-evaluated following 12 months of peritoneal dialysis (PD) treatment. RESULTS: Serum leptin levels correlated negatively to GFR (r = -0.26; P < 0.0001). The ob gene expression was significantly lower in patients with CRF than in healthy controls. A negative correlation between serum leptin levels and ob gene expression (r = -0.66; P < 0.05) was found in patients with CRP < 25 mg/liter. The ob gene expression (20.0 +/- 1.8 vs. 15.0 +/- 1.0 nCi/g; P < 0.05) was significantly higher in 5 patients with CRP > 25 mg/liter than in 10 patients with CRP < 25 mg/liter. Following 12 months of PD, the amount of body fat increased by 30% while the ob gene expression remained unchanged. CONCLUSION: The present study shows a correlation between serum leptin levels and GFR, and our results suggest that elevated leptin levels, due to a decreased plasma clearance, down-regulate the expression of the ob gene. We also found that an ongoing inflammation stimulates ob gene expression in patients with CRF. Therefore, it is suggested that the hyperleptinemia induced feedback inhibition of ob gene expression is overcome by inflammatory cytokines.     

Intravenous diltiazem and acute renal failure after cardiac operations

BACKGROUND: Perioperative administration of intravenous diltiazem to patients undergoing cardiac procedures has been shown to decrease the incidence of ischemia and arrhythmias. However, after adopting this practice in our cardiac surgery program, we perceived an increased incidence of postoperative renal dysfunction. METHODS: A directed record review of postoperative renal function was conducted for consecutive patients undergoing cardiac operation for the time periods before and after adoption of prophylactic intravenous diltiazem (0.1 mg.kg-1.h-1 for 24 hours). The two groups were compared using chi 2 and two-sample t tests. The risk of development of postoperative renal failure was modeled with logistic regression. RESULTS: Diltiazem-treated patients (n = 271) were similar to the control patients (n = 143) in terms of age (64 versus 61 years; p = 0.14), ejection fraction (0.46 versus 0.47; p = 0.61), baseline serum creatinine level (1.2 versus 1.1 mg/dL; p = 0.27), prevalence of comorbid conditions, and surgical characteristics. The prevalence of left main coronary artery disease was lower in the diltiazem group than the control group (39% versus 52%; p = 0.01). During the 7-day postoperative period, the average peak serum creatinine level was higher in the diltiazem group (1.7 +/- 0.9 mg/dL; mean +/- 1 standard deviation) than the control group (1.5 +/- 0.5 mg/dL; p = 0.003). The incidence of acute renal failure requiring dialysis was 4.4% in the diltiazem group versus 0.7% in the control group (p = 0.04). There was no difference in length of hospitalization or mortality. The risk of acute renal failure was strongly associated with intravenous diltiazem (adjusted odds ratio [AOR] 6.3; p = 0.08), age (AOR 2.5 per 10 years; p = 0.07), baseline serum creatinine (AOR 4.8 per 1 mg/dL; p = 0.02), the presence of left main coronary disease (AOR 5.3; p = 0.02), and the presence of cerebrovascular disease (AOR 4.5; p = 0.05). CONCLUSIONS: Our retrospective analysis suggests that prophylactic use of intravenous diltiazem in patients undergoing cardiac operations was associated with increased renal dysfunction. Further studies of the risk and benefits of intravenous diltiazem in this setting should be undertaken.     

The impact of a national impregnated bed net programme on the outcome of pregnancy in primigravidae in The Gambia

The effect of the non-ionic contrast medium iohexol (Omnipaque) on renal function was investigated in diabetic patients with signs of peripheral ischaemia. Forty-six patients, 70 +/- 11 years (mean +/- SD) old, age at diabetes diagnosis 53 +/- 17 years, and with varying degrees of diabetic nephropathy were studied before 1, 2, and 30 days after aortobifemoral arteriography. Serum creatinine, creatinine clearance, urinary excretion of immunoglobulin G, albumin collagen IV (NC1), kappa and lambda chains, alpha-1 microglobulin and Tamm-Horsfall protein were evaluated. Within 1 month before and 30 days after arteriography, the glomerular filtration rate was measured by clearance of iohexol. The acute effect of the radiocontrast medium was an increase in the serum creatinine level in 41 (89%) patients, with a more than 25% increase in 12 (26%) patients. The excretion rates of immunoglobulin G and albumin decreased, whereas the proximal and distal tubular function and the excretion of collagen IV did not change. The increment in serum creatinine was associated with the preangiographic renal function (p < 0.05), a history of heart failure (p < 0.01), but not with age, duration and type of diabetes, gender, systolic or diastolic blood pressure, glycated haemoglobin (HbAlc) or blood glucose levels. The increase of serum creatinine was associated with a pre-existing proximal tubular dysfunction and a worsening of distal tubular function. No changes in the parameters measured persisted 30 days after angiography. In summary, a transient increment in serum creatinine level after arteriography occurred in 89% of diabetic patients. It was associated with the preangiographic renal function, a history of heart failure and signs of preexisting proximal tubular dysfunction and worsening of distal tubular function. However, these changes were reversible.     

Hypouricemia in patients with meningitis

Serum urate and sodium concentrations were measured in 23 patients with acute viral and bacterial meningitis. Serum urate level was 3.0 +/- 0.2 mg/dl (mean +/- S.D.) (3.6 +/- 1.2 mg/dl in male and 2.5 +/- 0.9 mg /dl in female) on admission, but gradually elevated with improvements of meningitis. It turned to 4.8 +/- 0.2 mg/dl after recovery, and the value on admission was significantly lower than that after recovery (p < 0.0001). Serum sodium level was 137.6 +/- 2.9 mEq/l on admission and 139.7 +/- 2.7 mEq/l after recovery; also lower in the former (p < 0.01). These results show that patients develop transient hypouricemia, which may be explained by SIADH (syndrome of inappropriate secretion of ADH), although SIADH is subclinical in most cases of meningitis.     

Automatic continuous venovenous hemodiafiltration in cardiosurgical patients

Intermittent substitutive treatments in severely ill patients with acute renal failure are difficult or not suitable because of technical problems and/or hemodynamic instability. Continuous venovenous hemodiafiltration allows an adequate, slow removal of fluid, electrolytes, and waste products by combining diffusive and convective solute transport. Eight patients with acute renal failure, after cardiovascular surgery and cardiogenic shock, were treated by continuous venovenous hemodiafiltration. An automatic system (Equaline System, Amicon Division, USA) was employed. Venous accesses (femoral or subclavian) were used with double lumen catheters. A polysulfone filter (0.4 m2) was used in the study. Blood flow was 30 ml/min and dialysate flow rate 16.6 ml/min. Sterile pyrogen-free hemofiltration substitution fluid was used as dialysate. Mean duration of treatment was 10.3 +/- 3.2 days. After 72 hours blood urea nitrogen levels dropped from 136 +/- 46.13 to 53.5 +/- 12.3 mg/dl and creatinine levels dropped from 6.9 +/- 1.7 to 2.6 +/- 0.9 mg/dl. A controlled steady-state was then maintained. Mean urea clearance was 21 +/- 5.3 ml/min; mean ultrafiltration rate was 20.3 +/- 4.1 L/day. Continuous venovenous hemodiafiltration, with the Equaline System, is effective for the clearance of waste products and is able to maintain perfect fluid balance in catabolic patients with acute renal failure and multiple organ failure.     

Acute renal failure in patients with acute pancreatitis

We describe five patients with acute pancreatitis in whom acute renal failure developed in the absence of hypotension. Pancreatitis was diagnosed clinically, with mean serum and urinary amylase levels of 766 +/- 197 (SE) and 2,378 +/- 572 units/100 ml, respectively. Acute renal failure developed within 24 hours after admission in all patients. It was manifested by oliguria, elevated levels of serum creatinine (mean, 6.9 +/- 1.1 mg/100 ml) and BUN (105 +/-28 mg/100 ml); a urinary sodium level of 72.0 +/- 6.6 mEq/liter; and isosmotic urine (355 +/- 31 mOsm/liter). The mean uric acid level was 18.6 +/- 1.6 mg/100 ml. Blood pressure was recorded frequently, and the lowest mean diastolic pressure was 96 +/- 6 mm Hg. The duration of the oliguric phase of acute renal failure was 8.2 +/- 1.7 days, and all patients recovered from both the acute pancreatitis and acute renal failure. In summary, acute pancreatitis, per se, can precipitate acute renal failure. It occurs early in the course of the pancreatitis, and extreme hyperuricemia is frequent finding that does not adversely affect the recovery of renal function.