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CE ARTICLE number of kidney transplants is quite low compared to the actual need. At the end of 2010, there were more than 400,000 patients on dialysis and only 180,000 living with kidney transplants. While the many causes for renal failure will be discussed later in this article, diabetes is by far the leading cause of ERSD, and its incidence has been increasing since 1996.4 Together, diabetes and hypertension are the primary causes of kidney disease in more than 70% of cases.5 Normal Renal Physiology The kidney is a bean-shaped organ found in the retroperitoneal region. It is located just lateral to the vertebral column between the 12th thoracic and third lumbar vertebra. Typically the right kidney is situated slightly inferior compared to the left because of the liver (Figure 1). Like all solid organs, the kidney is enclosed in a Table 1: Urine output In Renal Failure Normal..................... 0.5-1mL/kg/hr Non-oliguria ............ >400mL/day Oliguria .................... 50-400mL/day Anuria ...................... <50mL/day fibrous capsule that provides protection. Blood enters the kidney through the renal artery at the hilum, which is the deep slit in the kidney's medial aspect. The continuous pale outer tissues of the kidney are known as the renal cortex, which surrounds the inner renal medulla. The shape and interaction of the renal medulla and cortex cause the medulla to take on triangular shapes known as renal pyramids. Found within the renal cortex and medulla is the nephron, the kidney's microscopic functioning unit. The nephron serves as the body's filter and removes toxins and wastes from the blood. Each Knox MedVault Drug Locker ® ® reDu ce exP oSu re t o nar co tI cS thef t P r ot ec t y o u r D e Pa rtM e n t, S ta f f a n D I n V en t o ry • neW – WiFi Remote Administration • Narcotic Access Control & Accountability • neW – Two Sizes Available • Know Who Accessed Narcotics & When 800-552-5669 • knoxbox.com 1601 W. Deer Valley Road, Phoenix, AZ 85027 • www.knoxbox.com • info@knoxbox.com For More Information Circle 37 on Reader Service Card 52 MARCH 2013 | EMSWORLD.com kidney has roughly 1.25 million nephrons that total a length of more than 145 km. The nephron (Figure 1A) has two primary structures: the renal corpuscle and the renal tubule. The renal corpuscle (in the cortex) filters blood at the glomerulus into Bowman's capsule. The glomerulus is a capillary network and is enveloped by Bowman's capsule, which is the start of the nephron's waste collection system. The two are separated by a thin epithelial wall. It is within the glomerulus where the blood pressure forces fluid and dissolved solutes out of an arteriole and into Bowman's capsule. The fluid and solutes forced from the blood are called filtrate and drain into the proximal convoluted tubule. Damage to the barrier between the glomerulus and Bowman's capsule will lead to CKD. Once in the proximal convoluted tubule, filtrate drops down into the loop of Henle, where the body reabsorbs sodium, potassium and roughly 90% of the fluid within the filtrate. This concentrates the filtrate; at the same time, additional wastes are added. Filtrate then leaves the loop of Henle and enters the distal renal tubule, where the body excretes toxins, acids, drugs and free ions. Additional sodium is also reabsorbed. Several renal tubules combine into a collection duct, at which point the filtrate is considered urine. The collection ducts continue to grow in size as more tubules combine, and all of the ducts drain into what eventually becomes the ureter and then the bladder. A healthy individual produces 0.5–1 mL/ kg/hr of urine in a day. When patients progress toward renal failure, there are different terms for the amount of urine they produce (Table 1). Acute Renal Failure It's important to understand the difference between acute renal failure (ARF) and chronic renal failure (CRF). More than 50 pathologies can lead to ARF; some of the most common are identified in Table 2. ARF is recognized through a rapid decline in renal function and urine output at a rate measured in hours or days. During this decline the patient's body quickly loses homeostasis as toxins accumulate and electrolyte balances are lost. ARF is