Acute renal failure in cardiac surgical patients, potentiated by gentamicin and calcium

Surgical prophylaxis with gentamicin and acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Gentamicin has been increasingly used instead of cephalosporins for surgical prophylaxis in an attempt to reduce the rate of "Clostridium difficile" infection. There are limited data regarding nephrotoxicity related to gentamicin in these patients.

METHODS

We have conducted a systematic review and meta-analysis to evaluate the risk of acute kidney injury (AKI) in gentamicin-containing surgical prophylactic regimens, compared to regimens without gentamicin, in several types of surgery. Electronic searches were performed using PubMed and Embase, including terms for "AKI, gentamicin, and surgical prophylaxis" with and without MeSH/EMTREE functions. Statistical analysis was then performed using a random-effect model; risk ratios (RR), risk differences (RD) and heterogeneity (I²) were calculated. Funnel plot was used for assessment of publication bias.

RESULTS

Eleven studies with fifteen cohorts with 18,354 patients were included in the analysis. Subgroup analysis was performed according to surgery type. We have found that antibiotic prophylaxis with gentamicin containing regimen has significant risk for developing postoperative AKI in orthopedic surgery (RR 2.99; 95% CI: 1.84, 4.88). The results were inconclusive in other types of surgery. Funnel plot indicates potential publication bias.

CONCLUSIONS

Gentamicin-induced AKI is significant in patients undergoing orthopedic surgery. Physicians should consider risks and benefits of using this regimen in individual patients.

Drug Class Combination–Associated Acute Kidney Injury

Objective: To evaluate the quality of available evidence of drug class combinations and their association with the development of acute kidney injury (AKI). Data Sources: A search of MEDLINE and Embase databases was completed using the following terms: “risk factor AND (acute kidney injury or acute kidney failure) AND (drug or medication).” Study Selection and Data Extraction: Inclusion criteria were the following: English language, full-text availability, and at least 1 drug-combination. Each citation was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria. The literature was evaluated using the quality of evidence component of GRADE. No standardized definition of AKI was applied throughout.. Data Synthesis: Out of 2139 total citations, 151 were assessed for full-text review, with 121 citations (6%) meeting inclusion criteria, producing76 unique drug class combinations. Overall, 56 combinations (73.7%) were considered very low quality; 12 (15.8%) were considered low quality. There were 8 (10.5%) of moderate quality, and no combination was considered high quality. 58 (76%) combinations that had a single citation,with a mean of 1.6 citations per drug class combination. The combination of nonsteroidal anti-inflammatory drugs (NSAIDs) and diuretics was reported in 10 citations, the largest number of citations. Conclusions: Our study demonstrates a lack of well-designed studies addressing drug class combination–associated AKI. The combination of NSAIDs and diuretics with or without additional renin-angiotensin aldosterone agents had the strongest level of evidence. Despite limitations, the information included in this review may result in additional scrutiny about combining certain individual nephrotoxic drugs.

Pro/con debate: should synthetic colloids be used in patients with septic shock?

You have recently heard reports that synthetic colloids may be associated with renal failure and other morbidities in certain populations of critically ill patients. You have been asked by the hospital chief of staff whether there should be a suspension of the use of synthetic colloids until further information is available. You need to make a decision.

Renal impact of fluid management with colloids: a comparative review

BACKGROUND AND OBJECTIVES

Colloids such as hydroxyethyl starch (HES), gelatin, dextran and albumin are useful for maintaining renal perfusion and function. The comparative renal effects of colloids have not been previously reviewed.

METHODS

Computer searches of the MEDLINE and EMBASE bibliographic databases and the Cochrane Library were conducted using the search terms: colloids; hetastarch; gelatin; dextrans; serum albumin; kidney failure; cardiac surgical procedures; and kidney transplantation. Relevant studies were also sought through hand searching and examination of reference lists. Results of identified studies were qualitatively summarized with account taken for potential confounding factors.

RESULTS

The three artificial colloids HES, gelatin and dextran all exhibited troublesome renal side-effects. Randomized trials have demonstrated adverse renal effects of HES in sepsis and surgery. Undesirable renal effects are common to all available HES solutions regardless of molecular weight, substitution or C2/C6 ratio. While some of its effects may be less severe than those of HES, gelatin also can adversely affect the kidney. A negative renal impact of dextran is well-established, although this colloid is now less extensively used than formerly. As the normal endogenous colloid, albumin exhibits a wide margin of renal safety, although albumin overdose needs to be avoided. Albumin also appears to exert protective effects on the kidney such as inhibition of apoptosis and scavenging of reactive oxygen species.

CONCLUSIONS

Colloids display important differences in their actions on the kidney. These contrasting renal effects should be considered in making fluid management decisions.

Early Audit of Renal Complications in a New Cardiac Surgery Service in Australia

OBJECTIVE

To assess the incidence of renal failure in a cardiac surgery service commencing in Australia.

DESIGN

Prospective data collection and retrospective database analysis.

SETTING

A tertiary referral, university teaching hospital in the state of Victoria, Australia.

PARTICIPANTS

The first 502 patients undergoing cardiac surgery in this institution from commencement of the service.

RESULTS

The overall rate of renal failure was low in comparison to other studies at 0.2% (95% CI 0.04-1.3%). The rate of postoperative renal dysfunction was also low at 4.2% (95% CI 2.7-6.5%).

CONCLUSIONS

The safety of the new service with respect to this complication of cardiac surgery was good when compared with published data. However the lack of uniform definitions of renal failure following cardiac surgery make comparisons between studies difficult. Uniform reporting of this complication would facilitate comparisons between units and quality assurance activities in this field.

The effect of calcium load and the calcium channel blocker verapamil on gentamicin nephrotoxicity in rats

Gentamicin (GM) is used against serious and life-threatening Gram negative infections. However its use is limited by the occurrence of nephrotoxicity. Reports on the interaction between GM nephrotoxicity and calcium (Ca(2+)) or Ca blockers are conflicting. Therefore, in the present work we assessed the effect of treatment of rats with graded doses of calcium carbonate, CaCO(3) (0.25, 0.5 or 1.0 g/kg) orally, or the Ca(2+) channel blocker verapamil (1.75, 3.5 or 7.0 mg/ kg) intramuscularly (i.m.), on the nephrotoxicity induced by concomitant i.m. treatment with GM (80 mg /kg/day for 6 days). Nephrotoxicity was evaluated histopathologically by light microscopy and biochemically by measuring the concentrations of urea and creatinine in plasma, reduced glutathione (GSH), lipid peroxidation and superoxide dismutase (SOD) activity in kidney cortex. The results indicated that the administration of CaCO(3) produced a dose-dependent amelioration in the biochemical indices of nephrotoxicity in plasma and renal cortex, which was significant at the two higher doses used. The histological picture of the renal proximal tubules followed a similar pattern. Treatment with verapamil induced a dose-dependent potentiation in the biochemical parameters of nephrotoxicity that was significant only at the highest dose used (7 mg/kg). This dose also exacerbated the GM-induced histological necrosis. The above interactions may be clinically relevant in patients treated concurrently with these agents.

Ionized serum calcium levels during acute renal failure: intermittent hemodialysis vs. Continuous hemodiafiltration

BACKGROUND

Achieving "adequacy of dialysis" includes the maintenance of normal serum ionized calcium concentrations and is an important therapeutic goal in the treatment of acute renal failure (ARF). It is unknown whether this goal is best achieved with intermittent or continuous renal replacement therapy.

METHODS

We compared the effects of continuous veno-venous hemodiafiltration (CVVHDF) and intermittent hemodialysis (IHD) on serum ionized calcium concentrations using daily morning blood tests in 88 consecutive intensive care patients of which half were treated with IHD and half with CRRT.

RESULTS

Mean patient age was 54 +/- 14 years for IHD and 60 +/- 14 years for CVVHDF (NS). However, patients who received CVVHDF were significantly more critically ill (mean APACHE II scores: 24.4 +/- 5.1 for IHD vs. 29.2 +/- 5.7 for CVVHDF, p < 0.003). Before treatment, the mean ionized calcium concentration was 1.177 +/- 0.03 mmol/l for IHD and 1.172 +/- 0.04 mmol/l for CVVHDF (NS), with abnormal values in 51.6% of IHD patients and in 68% of CVVHDF patients (NS). During treatment, hypocalcemia was significantly more common among CVVHDF patients (24.5% vs. 14.9%; p < 0.011) while hypercalcemia was more frequent during IHD (36.1% vs. 25.6%; p < 0.019).

CONCLUSIONS

Abnormal serum ionized calcium concentrations are frequent in ARF patients before and during renal replacement. Once dialytic therapy is applied, CVVHDF is more likely to lower serum calcium concentrations, while IHD is more likely to induce hypercalcemia. Appreciation of these different biochemical effects may assist clinicians in adjusting dialytic therapy in selected patients.