urine output is a key indicator of fluid balance. In a person who is maintaining a good fluid balance, urine output is neither too high nor too low.
Oliguria is the state of voiding a very small amount of urine over a given period of time (for example, voiding only 100 to 400 mL of urine over 24 hours). Olig- means “few” and -uria means “urine.” A person who is dehydrated might become oliguric (that is, have a urine output that is well below normal).
Polyuria (poly- means “many”) is excessive urine output. Polyuria, also known as diuresis, can be a sign of a health problem. For example, polyuria can be a symptom of poorly controlled diabetes. Or, polyuria may be the desired effect of a medication. For example, a person who is retaining excessive amounts of fl uid (for example, as the result of a heart disorder) may be put on a medication called a diuretic to help rid the body of the extra fl uid. The polyuria that results is a sign that the medication is having the desired effect. Evaluating a person’s urine output is also a good way to determine how well a person’s kidneys are working.
Anuria (an- means “none”) is defined as the state of voiding less than 100 mL of urine over the course of24 hours. Anuria usually indicates that a person is in kidney failure.
Not all of the people you care for will need to have their urine output measured and recorded, but people who have illnesses or take medications that may alter their body’s ability to maintain a healthy fluid balance will need to have their urine output measured regularly. Some people who are critically ill will have their urine output measured and recorded every hour, but most people in the health care setting have routine orders for their urine output to be measured and recorded each shift. If a person uses a regular toilet, you will need to remind the person to void into a specimen collection device (“commode hat”) and to call you after he or she has finished voiding so that you can measure and record the amount of urine. Specimen collection devices, urinals, and the drainage bags used with urinary catheters often have markings that make measuring urine output easy. If they do not, then the urine output can be measured by pouring it into a graduate. A graduate is also used to measure urine output if a person voids into a bedpan or bedside commode bucket. Remember to place the graduate on a fl at surface when measuring urine so that your measurements are accurate. If the urine output of one of your residents or patients is being monitored, you will need to keep a record of the amount of urine passed at each voiding. Some intake and output (I&O) fl ow sheets will have spaces to record the amount of each individual voiding, while others may only have a space to record the end-of-shift amount. To obtain the end-of-shift amount, simply add the individual amounts together and record the total in the appropriate space.