The Metric System (Chapter 3)

Clinical Application Problem The M.D. orders 2.5 L of a solution. How many cL is this?

250 cL

Clinical Application Problem The M.D. orders ascorbic acid 0.25 g p.o. How many mg of the drug will the nurse give?

250 mg

Clinical Application Problem The patient stated that he run 5 meters before falling down. How many kilometers did the patient run?

0.005 km

Clinical Application Problem The physician orders Synthyroid 1500 mcg p.o. daily for the patient. How many mg of Synthroid will the nurse give?

1.5 mg

Clinical Application Problem The physician orders 0.001 g of a liquid medication. The medication is available in micrograms. How many micrograms will the nurse give?

1000 mcg

Clinical Application Problem The patient has a bruise that measures 25 mm. How many cm is this?

2.5 cm

If the Decimal Point is Already in the Problem

Apply the steps to solve the following problem. -Identify the starting unit of measurement. -Look at the desired unit of measurement. -How many decimal places? -Move the decimal point to the desired place.

Clinical Practice... Problem: The M.D. orders 1700 mcg of a drug. How many mg is this?

Identify the starting unit of measurement (mc). Look at the desired unit of measurement (m). How many decimal places? Move the decimal point to the desired place (m).

Metric Base Units of Measure Used in Drug Dosage Calculations

Meter Gram Liter

Key Points to Remember

Place the decimal point after the whole number, 1700. Note three movements of the decimal point. Move the decimal point three places, from the micro place to the milli place 1.7 0 0. (right to left). 1700 mcg = 1.7 mg.

The Metric System

Standard measuring system used throughout the world It is based on the decimal system It consists of standard base units of measurement such as: meter (length) liter (volume) gram (weight) It uses prefixes and symbols that represent a numeric value

Moving the Decimal Point

The decimal point is already in the problem. Note three movements of the decimal point. Move the decimal point three times, from the base unit to the "milli" place, 1.5 0 0. (left to right). Add zeros as place holders, so that 1.5 L = 1500 mL.

Placing the Decimal Point

The decimal point is placed after the whole number Place decimal point after the whole number, 3. Note one movement of the decimal point. Move the decimal point one place, from centi to "deci", .3. (right to left). Place a zero in front of a decimal point when there is no number, so that 3 cm = 0.3 dm

The Decimal System

The decimal system is a number system based on multiples of 10. Notice how the number 1 increases or decreases in value when multiplied or divided by multiples of 10. The whole numbers increase by a multiple of 10 from right to left, for example: (10 x 10 = 100), (100 x 10 = 1000 ). The decimal numbers decrease by a multiple of 10 from left to right, for example: (1 divided by 10 = 0.1), (1 divided by 100 = 0.01).

The Metric System & The Decimal System

The metric system also consists of prefixes and symbols that represent the multiple of 10 within the decimal system 1000 - kilo - k 100 - hecto - h 10 - decka - da 0.1 - deci - d 0.01 - centi - c 0.001 - milli - m 0.000001 - micro - mc The ten-thousandth place and the hundred-thousandth place are not identified by a prefix or symbol in medication administration. It is important to remember their placement when converting between the milli place and the micro place.

The Metric System and the Standard Base Units of Measure

The standard base units of measure identify liquid volume (liter - L), weight (gram - g), and length (meter - m) The standard base units can be placed on the line with the metric prefixes and symbols to form the metric line.

Moving of the Decimal Point Using the Metric Line

To move from one metric place to another apply the following steps using the metric line: -Identify the starting unit of measurement. -Look at the desired unit of measurement. -How many decimal places? -Move the decimal point to the desired place

Working With The Metric Line

Working with the metric line means moving the decimal point from one place on the line to another place on the line. Note that there is one decimal place between each metric symbol, except between the milli (m) place and the micro (mc) place where there are 3.

Meter

standard metric base unit for length a meter is slightly more than 3 feet 3 inches or equivalent to 39.37 inches

Gram

standard metric base unit for mass a gram is approximately equivalent to the weight of a small paper clip

Liter

standard metric base unit for volume a liter is slightly more than 1 quart or equivalent to 32 fluid ounces