Overview
This lecture covers essential math concepts for healthcare professionals, focusing on decimal calculations and metric system unit conversions frequently used for medication dosages.
Decimals in Medication Calculations
- Decimal calculations are critical in medication dosing; mistakes can lead to overdosing or underdosing.
- Always place a zero before the decimal (e.g., 0.25 mg, not .25 mg) to avoid misreading.
- The position after a decimal is tenths (0.1), hundredths (0.01), and thousandths (0.001).
- When rounding decimals: 5 or higher rounds up, 4 or lower rounds down (e.g., 10.35 → 10.4).
- Sometimes rounding to the hundredth is required, especially for body surface area calculations.
Metric System Basics
- The metric system is used almost exclusively in healthcare for measuring medications.
- Main metric base units: meter (m) for length, gram (g) for weight, liter (L) for volume.
- Metric prefixes indicate size: kilo- (1000 times), milli- (1/1,000), micro- (1/1,000,000), centi- (1/100).
- For drug weights: kilograms (kg), grams (g), milligrams (mg), micrograms (mcg).
- For volume: liters (L), milliliters (mL).
- For length: centimeters (cm) and millimeters (mm).
Metric Unit Conversions
- Moving from a larger to a smaller unit (e.g., grams to milligrams), shift the decimal three places to the right.
- Moving from a smaller to a larger unit (e.g., milligrams to grams), shift the decimal three places to the left.
- Example: 1 gram = 1,000 milligrams; 1 gram = 1,000,000 micrograms.
- Example: 1 milligram = 0.001 grams.
- Example with volume: 4 liters = 4,000 milliliters.
Key Terms & Definitions
- Decimal Point — Separates the whole number from the fractional part in a number.
- Metric System — A decimal-based measurement system used in healthcare.
- Base Unit — Fundamental units like meter, gram, liter in the metric system.
- Prefix — Letters added before metric units to indicate multiples or fractions (e.g., kilo-, milli-, micro-).
Action Items / Next Steps
- Review the rounding cheat sheet provided on Blackboard.
- Watch the remaining videos in this unit.
- Practice decimal and metric conversions as shown in examples.