Acute hyperkalemia associated with intravenous epsilon-aminocaproic acid therapy

Postoperative hyperkalemia

Hyperkalemia occurs frequently in hospitalized patients and is of particular concern for those who have undergone surgery, with postoperative care provided by clinicians of many disciplines. This review describes the normal physiology and how multiple perioperative factors can disrupt potassium homeostasis and lead to severe elevations in plasma potassium concentration. The pathophysiologic basis of diverse causes of hyperkalemia was used to broadly classify etiologies into those with altered potassium distribution (e.g. increased potassium release from cells or other transcellular shifts), reduced urinary excretion (e.g. reduced sodium delivery, volume depletion, and hypoaldosteronism), or an exogenous potassium load (e.g. blood transfusions). Surgical conditions of particular concern involve: rhabdomyolysis from malpositioning, trauma or medications; bariatric surgery; vascular procedures with tissue ischemia; acidosis; hypovolemia; and volume or blood product resuscitation. Certain acute conditions and chronic co-morbidities present particular risk. These include chronic kidney disease, diabetes mellitus, many outpatient preoperative medications (e.g. beta blockers, salt substitutes), and inpatient agents (e.g. succinylcholine, hyperosmolar volume expanders). Clinicians need to be aware of these pathophysiologic mechanisms for developing perioperative hyperkalemia as many of the risks can be minimized or avoided.

Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues

This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides resulting in dose-limiting high kidney radiation doses. Radiation nephropathy has been described in several patients. Studies on the mechanism and localization demonstrate that renal uptake of radiolabelled somatostatin analogues largely depends on the megalin/cubulin system in the proximal tubule cells. Thus methods are needed that interfere with this reabsorption pathway to achieve kidney protection. Such methods include coadministration of basic amino acids, the bovine gelatin-containing solution Gelofusine or albumin fragments. Amino acids are already commonly used in the clinical setting during PRRT. Other compounds that interfere with renal reabsorption capacity (maleic acid and colchicine) are not suitable for clinical use because of potential toxicity. The safe limit for the renal radiation dose during PRRT is not exactly known. Dosimetry studies applying the principle of the biological equivalent dose (correcting for the effect of dose fractionation) suggest that a dose of about 37 Gy is the threshold for development of kidney toxicity. This threshold is lower when risk factors for development of renal damage exist: age over 60 years, hypertension, diabetes mellitus and previous chemotherapy. A still experimental pathway for kidney protection is mitigation of radiation effects, possibly achievable by cotreatment with amifostine (Ethylol), a radiation protector, or with blockers of the renin-angiotensin-aldosterone system. Future perspectives on improving kidney protection during PRRT include combinations of agents to reduce renal retention of radiolabelled peptides, eventually together with mitigating medicines. Moreover, new somatostatin analogues with lower renal retention may be developed. Furthermore, knowledge on kidney protection from radiolabelled somatostatin analogues may be expanded to other peptides.

Salbutamol to facilitate management of acute hyperkalemia in liver transplantation: a case report

PURPOSE

Acute hyperkalemia is a frequent, potentially life-threatening complication in orthotopic liver transplantation (OLT). We describe a case of acute hyperkalemia during the pre-anhepatic stage that remained persistent despite conventional treatment, including calcium salts, insulin and glucose, sodium bicarbonate, and furosemide.

CLINICAL FEATURES

A 50-yr-old man with end-stage hepatitis B liver cirrhosis underwent living donor liver transplantation, receiving a right lobe graft donated by his son. The initial serum potassium concentration was 4.6 mEq l(-1). Despite conventional management, the serum potassium concentration increased to 6.6 mEq l(-1), intraoperatively. Since about 90 min elapsed from the division of the hepatic artery and the portal vein to the clamping of the suprahepatic inferior vena cava, the persistent hyperkalemia may have resulted from loss of potassium from ischemic liver cells into the systemic circulation. After incorporating nebulized salbutamol, a selective beta(2)-agonist, into the combined therapeutic regimen (sodium bicarbonate and insulin with glucose), the serum potassium concentrations rapidly normalized.

CONCLUSIONS

This case suggests that acute and relatively refractory hyperkalemia can develop when surgical interruption of hepatic inflow is prolonged during hepatectomy in patients undergoing OLT using the piggyback technique. In such situations, incorporating nebulized salbutamol with a conventional anti-hyperkalemia strategy can provide an effective therapeutic option to treat hyperkalemia, even during the anhepatic stage.

Potential side effects of renin inhibitors – mechanisms based on comparison with other renin–angiotensin blockers

Angiotensin (Ang) II plays important roles in the development of hypertension and cardiovascular and renal injury. Pharmaceutical approaches to block its activity led to the development of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. Numerous trials have documented their efficacy in controlling blood pressure, minimising left ventricular remodelling, preventing progression to heart failure, ameliorating proteinuria and retarding renal disease progression. Although they are considered safe in general, there remain concerns about the potential for adverse events in certain target populations. Recently, several novel, low molecular weight renin inhibitors without the extended peptide-like backbone of previous renin inhibitors were developed with favourable pharmacokinetic properties. They have been shown to successfully reduce Ang II levels in normal volunteers and to lower blood pressure in patients with mild-to-moderate hypertension. In this review, the authors summarise current knowledge about these renin inhibitors.

Antifibrinolytics in orthotopic liver transplantation: current status and controversies

This article reviews the current status and controversies of the 3 commonly used antifibrinolytics-epsilon-aminocaproic acid, tranexamic acid and aprotinin-during liver transplantation. There is no general consensus on how, when or which antifibrinolytics should be used in liver transplantation. Although these drugs appear to reduce blood loss and decrease transfusion requirements during liver transplantation, their use is not supported uniformly in clinical trials. Aprotinin has been studied more extensively in clinical trials and appear to offer more advantages compared to two other antifibrinolytics. Because of the diverse population of liver transplant recipients and the potential adverse effects of antifibrinolytics, especially life-threatening thromboembolism, careful patient selection and close monitoring is prudent. Further studies addressing the risks and benefits of antifibrinolytics in the setting of liver transplantation are warranted.

The Effect of epsilon-aminocaproic acid on perioperative blood loss in patients with idiopathic scoliosis undergoing posterior spinal fusion: a preliminary prospective study

STUDY DESIGN

A prospective study evaluating the efficacy of epsilon-aminocaproic acid (EACA) in decreasing perioperative blood loss in idiopathic scoliosis.

OBJECTIVES

To compare the perioperative blood loss and need for blood replacement in two groups of patients undergoing surgery for idiopathic scoliosis. One group received intraoperative EACA; the other did not and served as controls.

SUMMARY OF BACKGROUND DATA

Excessive blood loss increases the operative time, risk for blood product disease transmission, postoperative complications, and costs associated with posterior spinal fusion and instrumentation. EACA is an antifibrinolytic agent that has been shown to be effective in reducing perioperative blood loss during pediatric cardiothoracic surgical procedures. We hypothesized that it would also be effective in lowering blood loss during posterior spinal fusion for idiopathic scoliosis.

METHODS

We compared the perioperative blood loss of 28 consecutive pediatric patients with idiopathic scoliosis who underwent posterior spinal fusion and received intraoperative EACA with 31 consecutive patients who did not receive this medication and served as a control group.

RESULTS

The patients in both groups were similar. Patients in the EACA group demonstrated statistically significant decreases in total estimated perioperative blood loss and the need for autologous blood transfusion. The patients in the EACA group had no intraoperative or postoperative complications related to the use of this medication.

CONCLUSIONS

Based on these preliminary findings, we believe that EACA is helpful in decreasing blood loss in patients undergoing posterior spinal fusion and instrumentation, and may decrease the number of autologous units needed to maintain safe perioperative hemoglobin levels, thereby improving safety and lowering cost associated with scoliosis surgery.

The association of epsilon-aminocaproic acid with postoperative decrease in creatinine clearance in 1502 coronary bypass patients

Renal dysfunction is a common serious complication after cardiac surgery. Reports of proteinuria and hyperkalemia after cardiac surgery with epsilon-aminocaproic acid (EACA) have therefore raised concerns for renal safety. Since EACA renders these markers unreliable, we used perioperative change in creatinine clearance (DCrCl) to test the hypothesis that EACA is associated with greater reductions in creatinine clearance after heart surgery, particularly for patients with renal disease. We evaluated data from all elective primary coronary bypass patients during EACA introduction at our institution (July 1, 1991-December 31, 1992; 10 g iv bolus pre-cardiopulmonary bypass, then 1 g/h for 5 h). DCrCl was calculated using preoperative (CrPre) and postoperative peak serum creatinine values, using the Cockroft-Gault equation. Patients with CrPre > or = 133 micromol/L were also separately analyzed. Evaluated patients (n = 1502, +/-EACA; 581/905, 16 exclusions) included 233 with CrPre > or = 133 micromol/L (+/-EACA; 98/135). Multivariate analyses confirmed several known risk factors, but no association between DCrCl and EACA in all patients (P: = 0.66), and the subgroup with CrPre > or = 133 micromol/L (P: = 0.42).

IMPLICATIONS

In a large population of primary Coronary Artery Bypass Graft including a subset with preoperative renal dysfunction, there were no postoperative reductions in creatinine clearance attributable to epsilon-aminocaproic (EACA) administration. This retrospective study suggests that moderate epsilon-aminocaproic acid dosing during cardiac surgery is safe for the kidney; however, this inference is based on a single marker of renal dysfunction and requires prospective confirmation using a variety of tests of renal function.

Drug-induced hyperkalemia: old culprits and new offenders

Prescribed medications, over-the-counter drugs, and nutritional supplements are used by many patients. Although most of these products are well tolerated, drug-induced hyperkalemia may develop in patients with underlying renal impairment or other abnormalities in potassium handling. Drug-induced hyperkalemia most often occurs from impaired renal potassium excretion. However, disturbed cellular uptake of a potassium load as well as excessive ingestion or infusion of potassium-containing substances may also occur. Physicians must be aware of medications that can precipitate hyperkalemia, how these drugs induce alterations in potassium homeostasis, and the patient characteristics that increase the risk of hyperkalemia.