Preoperative intravenous hydration confers renoprotection in patients with chronic kidney disease undergoing cardiac surgery. Renal dose dopamine in open heart surgery. Does it protect renal tubular function? Effect of venovenous bypass on perioperative renal function in liver transplantation: results of a randomized, controlled trial. Role of dopamine in renal dysfunction during laparoscopic surgery. Perioperative renal protection in patients with obstructive jaundice using drug combinations. N-acetylcysteine for preventing acute kidney injury in cardiac surgery patients with pre-existing moderate renal insufficiency. Effect of angiotensin converting enzyme inhibition on blood pressure and renal function during open heart surgery. Enhancing postoperative recovery of cardiac surgery patients: a randomized clinical trial of an advanced practice nursing intervention. Can renal dysfunction after infra-renal aortic aneurysm repair be modified by multi-antioxidant supplementation?
Patients with chronic kidney disease (CKD) are at risk to develop acute renal failure (ARF) after open heart surgery. This complication is associated with high morbidity, mortality, and cost. Because the ability to concentrate urine is lost early in the progression of CKD, renal patients kept on fluid restriction prior to surgery may develop severe dehydration, a situation consistently found to be one of the most critical risk factors for postoperative ARF. Our goal was to investigate whether intravenous hydration for 12 h prior to cardiac surgery could prevent acute renal injury in patients with CKD. This is a prospective study in a tertiary cardiac surgery center. Forty-five patients admitted for elective open heart surgery with moderate-to-severe CKD, as evidenced by a quantified glomerular filtration rate less than 45 mL/min, were assigned using a 2/1 randomization process, to either receive an intravenous infusion of half-isotonic saline (1 mL/kg/h) for 12 h before the operation (hydration group, n = 30, 29 men, 64 + 1.7 years old), or to be simply kept on fluid restriction (control group, n = 15, 14 men, 64.2 + 2.8 years old). Groups were not different in clinical and intraoperative variables associated with postoperative renal injury. ARF developed in 8 of 15 (53%) patients in the control group, but in only 9 of the 30 (30%) patients in the hydration group. Four patients in the control group (27%), but no one in the hydration group, required dialysis after the operation (P < 0.01). Peak creatinine and blood urea nitrogen values were two to three times higher in the control group than in the hydration group. Preoperative intravenous hydration may ameliorate renal damage in patients with moderate-to-severe renal insufficiency undergoing cardiac surgery. This prospective, randomized study assessed the effect of dopamine on renal tubular function in patients who had coronary artery bypass grafting.
                Two groups of patients with normal preoperative renal function were randomly divided into a dopamine group (n=11), who received dopamine in a dose of 2 mg/kg x min, and a control group (n=11), who received no treatment. Dopamine infusion was initiated 24 hours before the operation and was continued for 48 hours postoperatively. Measurements of renal function obtained 2 days before the operation were considered preoperative and were repeated on the 1st, 3rd, and 7th postoperative days. Urinary excretion of b2-Microglobulin (b2-M), considered a sensitive means for diagnosing proximal tubular damage, was measured during the early (day 3) and late (day 7) postoperative period.
                There were no significant differences respect to the clearances of creatinine, osmotic, and free-water in the dopamine group compared with the control group (p>0.05). Urine microalbumin levels significantly increased on postoperative day 3 in both groups. During the early postoperative period, excretion of urine b2-M was significantly greater in the dopamine group than in the control group (p<0.05).
                Consequently, in patients with normal preoperative renal and cardiac function scheduled for elective coronary artery bypass grafting, renal dose dopamine infusion alone may not provide sufficient protection on tubular function and increases renal tubular injury during the early postoperative period. Although venovenous bypass (VVBP) has been suggested to protect the kidneys during liver transplantation and its systematic use has therefore been recommended, this beneficial effect of VVBP has not been clearly demonstrated. In a prospective, randomized, controlled trial, 77 patients receiving liver transplants for chronic liver disease were allocated to be supported with VVBP (group 1, 38 patients) or not (group 2, 39 patients). Both groups were similar in relation to preoperative clinical and laboratory data and operative transfusion requirements. Inulin clearance and urinary beta(2)-microglobulin and N-acetyl-beta-D-glucosaminidase (NAG) excretion (to determine glomerular filtration rate and tubular damage, respectively) were measured at different perioperative periods (anesthesia induction, hepatectomy, anhepatic phase, biliary anastomosis, and 24 hours after surgery). A significant decrease in inulin clearance and increase in tubular damage markers were observed in the anhepatic phase, which only partly improved in the subsequent phases. No significant differences were observed between groups 1 and 2 at any perioperative phase, except during the anhepatic phase, in which a more marked renal function impairment occurred in group 2 patients. However, renal function on the 7th postoperative day and the need for hemodialysis/ hemofiltration during the 1st week were similar in both groups. Among 40 variables analyzed, only low mean arterial pressure at anesthesia induction was identified as an independent predictor for early postoperative severe renal failure (inulin clearance < 10 mL/min/1.73 m(2) at the 24th postoperative hour), with no significant relationship between this complication and the use of venovenous bypass. Renal function markedly deteriorates during liver transplantation, and renal impairment persists during the early postoperative period. Because VVBP support is not associated with any clear benefit in renal function, its systematic use does not seem to be justified. Sympathetic vascular insult and hemodynamic changes represent the most reliable explanation of renal impairment resulting from acute intraabdominal pressure. We evaluated the effects of low-dose dopamine administration during a long-lasting surgical laparoscopic procedure.
                For this study 40, patients submitted to a colorectal laparoscopic procedure with 15 mmHg of intraabdominal pressure were randomly allocated to two groups: 20 receiving 2 mg/kg/min of dopamine and 20 receiving the same perfusion of saline. Hemodynamic parameters, renal function, urinary output, and creatinine clearance, were studied.
                The hemodynamic parameters were similar in both groups. The urinary output decreased during the intraoperative period only the saline group (p = 0.4). Then 2 h postoperatively, it increased in both groups, and no statistically significant differences were found between the groups. The creatinine clearance decreased in both groups during the intraoperative time, but it was worse in the saline group (-28 +/- 120 vs -194 +/- 106; p = 0.022). During the postoperative period, both groups showed improvement, but in control group the values remained lower than at baseline (p = 0.04), and significantly lower than in the dopamine group (230 +/- 337 vs 100 +/- 192; p = 0.012).
                An intrabdominal pressure of 15 mmHg induces a time-limited renal dysfunction, and low doses of dopamine could prevent this undesirable effect. The effectiveness of dopamine alone or in combination with mannitol or furosemide in preventing postoperative renal dysfunction in patients with obstructive jaundice was assessed in this study.
                Forty patients having obstructive jaundice were randomly allocated into 4 equal groups. Preoperative hydration was performed by infusing all patients 1L of 5% dextrose the night before surgery and another 1L in the morning before surgery. Intra- and postoperative maintenance of adequate intravascular volume was assured by fluid and blood replacement guided by the monitoring of central venous pressure urine output and blood pressure. The 1st group was kept as a control. The other 3 groups received dopamine 2.5 micrograms/kg/min for 2 postoperative days starting before surgery. The 2nd group was maintained on dopamine alone, while mannitol (0.25 g/kg), every 12 hours for 2 postoperative days, was added to the 3rd group. Similarly furosemide (1 mg/kg) every 12 hours for 2 postoperative days, was infused to the patients of the 4th group. Postoperative renal functions were assessed by 24-hour urine output, serum creatinine, creatinine clearance and urine to plasma osmolality ratio.
                All these tests did not show significant changes in the 1st, 2nd and 7th postoperative days. Only transient decreased creatinine clearance and elevated serum creatinine were observed in the patients of the 4th group in the 1st and 2nd postoperative days. This may be attributed to fluid imbalance induced by furosemide in these patients who were older than the other groups.
                The study showed that careful attention to perioperative hydration is the cornerstone in preserving adequate renal function following surgery in patients with obstructive jaundice. Administration of dopamine alone or in combination with mannitol or furosemide did not confer more renal protection. N-acetylcysteine may prevent acute kidney injury after cardiac surgery. To determine if N-acetylcysteine warrants definitive evaluation in a large multicentre trial, we evaluated its effects on a surrogate outcome, estimated glomerular filtration rate (eGFR), in a randomized trial.
                One-hundred-seventy-seven cardiac surgery patients with moderate pre-existing renal insufficiency (eGFR <or= 60 mLxmin(-1)) were recruited in a blinded (patients, clinicians, data-collectors) placebo-controlled randomized trial. Eighty-nine were randomized to N-acetylcysteine (100 mgxkg(-1) i.v. bolus, 20 mgxkg(-1)xhr(-1) infusion until four hours after cardiopulmonary bypass), and 88 to placebo. The primary outcome was the percent change in eGFR during the first 72 postoperative hours. Secondary outcomes included renal replacement therapy, mortality, atrial fibrillation, vasoactive medications, and adverse effects. A future multicentre trial was deemed to be warranted if N-acetylcysteine was associated with a percent change in eGFR that was 3.8 better (small benefit), and with an upper 95% confidence interval including 9.5 (moderate benefit).
                The median percent change in eGFR was 5.2% better (absolute difference) in the N-acetylcysteine arm (95% confidence interval 2.4% worse to 12.1% better; P=0.22). With regard to secondary outcomes, all-cause mortality was lower in the N-acetylcysteine arm (0% vs 8%; P=0.007).
                N-acetylcysteine did not cause a statistically significant improvement in postoperative eGFR in this single-centre study. Nonetheless, its treatment effect was consistent with a plausible small-to-moderate benefit. Given this finding, N-acetylcysteine should be definitively evaluated in a large randomized trial. Activation of the renin-angiotensin system during open heart surgery may have consequences both beneficial in sustaining blood pressure and deleterious in compromising renal hemodynamics. The influence of short-term pretreatment with captopril on blood pressure and renal function was assessed double-blind versus placebo in 18 patients without pre-existing cardiac or renal failure, and undergoing coronary artery bypass. No difference in blood pressure and fluid requirement during the surgical period was observed between groups receiving captopril or placebo. Effective renal plasma flow and glomerular filtration rate decreased in the placebo group whereas they remained unaltered in the captopril group; during cardiopulmonary bypass, urinary excretion of sodium was greater in patients receiving captopril than those receiving placebo. These results suggest that captopril pretreatment does not compromise the control of blood pressure and renal function during open heart surgery; additional studies on the protective value of angiotensin-converting enzyme inhibitors are warranted in patients at higher risk for developing renal failure. The purpose of this trial was to determine the effectiveness of advanced practice nursing support on cardiac surgery patients' during the first 5 weeks following hospital discharge. Patients ( N = 200) were randomly allocated to two groups: (a) an intervention group who received telephone calls from an advanced practice nurse (APN) familiar with their clinical condition and care needs, twice during the first week following discharge then weekly thereafter for 4 weeks, and (b) a usual care group. Measures of health-related quality of life (HRQL), symptom distress, satisfaction with recovery care, and unexpected health care contacts were obtained at 5 weeks following discharge. There were no significant group differences in HRQL, unexpected contacts with the health care system, or symptom distress. The provision of APN support via telephone followup after cardiac surgery is feasible. However, further randomized trials of single and multicomponent APN interventions are needed to prove effectiveness. Renal failure after lower torso ischemia is a serious problem, partly caused by hypotension and indirect reperfusion injury. This injury is partly due to the formation of oxygen free radicals by activated neutrophils. This injury results in albuminuria and renal function impairment. There are indications that free radical damage in indirect reperfusion injury can be diminished by administering extra antioxidants before and during reperfusion.
                In this prospective randomised study we have looked at the influence of a multi-antioxidant supplementation on renal function in patients undergoing an elective open infrarenal abdominal aneurysm repair. The patients received either standard treatment (n=22) or standard treatment with additional antioxidants perioperatively (Allopurinol, vitamin E and C, N-acetylcysteine and mannitol). For renal function we have looked at the albumin/creatinine ratio in urine and 24 hr creatinine clearance.
                Despite significantly increased serum total antioxidant capacity, the group receiving extra antioxidants showed no decrease in the albumin/creatinine ratio in urine. There was however a significantly higher creatinine clearance in this group at day 2.
                The results indicate that the diminished renal function after infrarenal aneurysm repair may be influenced by antioxidant therapy.
There is no reliable evidence from the available literature to suggest that interventions during surgery can protect the kidneys from damage. There is a need for more studies with high methodological quality. One particular area for further study may be patients with pre-existing renal dysfunction undergoing surgery.