Measurement and Dimensional Analysis
Conversion Factors
Pound to Ounce: 1 pound equals 16 ounces.
Pound to Kilogram: 2.2 pounds equals 1 kilogram. This conversion is important in healthcare settings but noted as not frequently used.
Inch to Centimeter: 1 inch equals 2.54 centimeters. This conversion may not be commonly used but is necessary in measuring certain medical equipment or wound sizes.
Importance of Measuring Wounds
Purpose of Measuring Wounds:
To evaluate healing progression.
To determine if a wound is improving in size or is worsening.
Measurement Parameters:
Wounds are measured in three dimensions: length, width, and depth.
It was suggested that this measurement might not be on every quiz but could appear in future assessments.
Temperature Conversions
Celsius to Fahrenheit Conversion: The conversion formula from Celsius to Fahrenheit is commonly expressed, but the specific formula wasn't discussed in-depth.
Fahrenheit to Celsius Conversion: The order in which the conversions are presented may vary according to the individual’s study materials.
Metric Conversions
Centimeters to Millimeters:
1 centimeter equals 10 millimeters.
It's important to look up this conversion for correct dosage calculations.
Milliliters in a Liter:
1 liter equals 1000 milliliters.
Many IV bags for patient treatment are 1-liter bags, which contain 1000 mls.
Calculating Doses:
To express half of a liter, it should be represented as 0.5 liters.
It’s crucial to include the 0 before the decimal, avoiding trailing zeros after the decimal to maintain precision.
Dimensional Analysis for Medication Dosing
Order vs. Supply:
Example: If a doctor orders 90 mg of a medication, and you have a supply of 30 mg per ml:
Supply: 30 mg in 1 ml
Order: 90 mg
Set Up:
Write the order and supply ensuring that like terms are positioned accordingly for cancellation.
Order box: 90 mg; Supply box: 30 mg in 1 ml
Set up looks like:
\frac{90 \text{ mg}}{1} \times \frac{1 \text{ ml}}{30 \text{ mg}}Like terms (mg) cancel out, simplifying your analysis.
Multiplication:
Perform the multiplication after canceling out terms. Based on the example, you would multiply across.
Example Calculation:
\frac{90 \times 1}{30} = 3 \text{ ml}
Output of Calculation:
The result is expressed without labels for numeric entry but must acknowledge the units when relevant (i.e., 3 ml).
Guidelines for Rounding Numbers
Rounding Rules:
When rounding to the nearest whole number, observe the digit immediately to the right of the rounding place:
5 and above = round up.
4 and below = stay the same.
Examples of Rounding:
For 3.45: 4 (look at 4, round up).
For 3.44: 3 (look at 4, keep the same).
For 3.84: 4 (look at 8, round up).
Significance of Place Values:
The tenths place is crucial to identifying the precision of measurements.
In decimal places, indicate tenths with notation (th) as in tenths, hundredths, etc.
Important Rules:
Never round during calculations, as it introduces errors in dosage (e.g., 0.1 mg).
Ensure the number before the decimal point has a zero (e.g., 0.5) to maintain clarity.
Avoid trailing zeros at the end of a measurement (e.g., 4.30 should be represented as 4.3).
Final Thoughts on Medication Calculations
Accuracy is Critical: Miscalculations in medication can have serious consequences, especially in pediatrics. Always double-check conversions and calculations.
Practice Dimensional Analysis: Become proficient through examinations as it is foundational for future classes, particularly in advanced doses or complex calculations.