First-year courses · Health sciences

Nursing fundamentals: medical terms and dosage maths

Nursing student flashcards for vocabulary and arithmetic practice: medical prefixes and suffixes, vital sign terms, unit conversions and dosage maths.

42 cards4 topicsAbout 15 minutes a roundTypical first-year nursing fundamentals, medical terminology and dosage calculation practice

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About this deck

Please read this first: this deck is vocabulary and arithmetic practice for students. It is not clinical guidance and must never be used to make decisions about a real patient's care, medication or treatment. In practice, always follow the orders of the prescriber, your agency's policies, current drug references and the direction of your instructors and supervising nurses. The numbers in the examples are made up to practise arithmetic and are not recommended doses.

With that understood, this deck is for first-year nursing and other health sciences students learning the language and maths of the field. It covers common medical word parts (prefixes, suffixes and roots), the definitions of the vital signs and related measurements, metric conversions, and the standard dosage calculation set-ups: desired over have, weight-based calculations, concentrations and percentage solutions, IV flow rates and drip rates.

You need confident arithmetic with decimals, fractions and ratios. For word parts, build words: combine a root with different suffixes and say what each new word means. For calculations, write the set-up with units every time and cancel units before you touch the numbers; if the units do not cancel to what was asked for, the set-up is wrong. Then ask whether the answer is reasonable before you accept it.

Common mistakes: moving the decimal the wrong way in mg to mcg or g to mg conversions (a thousandfold error); dividing the wrong way round in desired over have; and writing a trailing zero such as 5.0 or a naked decimal such as .5, both of which are easily misread.

Before you start: Confident arithmetic with decimals, fractions, ratios and percentages; high school biology helps with the word roots.

All 42 cards

Cover the definitions with a sheet of paper and test yourself, or use the study modes above.

Prefixes

Brady-: Prefix meaning slow.Example: Bradycardia: a slower than usual heart rate.
Tachy-: Prefix meaning fast or rapid.Example: Tachypnea: rapid breathing.
Hyper-: Prefix meaning above, excessive or more than usual.Example: Hypertension: blood pressure above the usual range.
Hypo-: Prefix meaning below, under or less than usual.Example: Hypoglycemia: low blood glucose.
Dys-: Prefix meaning difficult, painful or abnormal.Example: Dysphagia: difficulty swallowing.
A- or an-: Prefix meaning without or absence of.Example: Apnea: absence of breathing. Anemia: deficiency of red blood cells or hemoglobin.
Peri-: Prefix meaning around or surrounding.Example: Pericardium: the sac around the heart.
Poly-: Prefix meaning many or much.Example: Polyuria: passing large volumes of urine.

Suffixes and roots

-itis: Suffix meaning inflammation.Example: Appendicitis: inflammation of the appendix.
-ectomy: Suffix meaning surgical removal.Example: Tonsillectomy: removal of the tonsils.
-otomy: Suffix meaning cutting into or incision.Example: Tracheotomy: an incision into the trachea.
-ostomy: Suffix meaning a surgically created opening.Example: Colostomy: an opening from the colon through the abdominal wall.
-algia: Suffix meaning pain.Example: Arthralgia: joint pain. Myalgia: muscle pain.
-emia: Suffix meaning a condition of the blood.Example: Hyperkalemia: high potassium in the blood.
-pnea: Suffix meaning breathing.Example: Dyspnea: difficult or laboured breathing.
-megaly: Suffix meaning enlargement.Example: Hepatomegaly: enlarged liver.
Cardi/o: Combining form meaning heart.Example: Cardiology: the study of the heart.
Nephr/o and ren/o: Combining forms meaning kidney (Greek and Latin origins).Example: Nephrology and renal failure both refer to the kidneys.
Hepat/o: Combining form meaning liver.Example: Hepatitis: inflammation of the liver.
Gastr/o: Combining form meaning stomach.Example: Gastroenteritis: inflammation of the stomach and intestines.

Vital signs and measurements

Vital signs: Core measurements of body function: temperature, pulse, respiratory rate and blood pressure; many settings add oxygen saturation and pain.Example: Recorded together with the time they were taken.
Pulse rate: The number of arterial pulsations felt per minute, reflecting heartbeats; adult resting reference ranges are often quoted as about 60 to 100 per minute.Example: Counting 18 beats in 15 seconds gives 18 x 4 = 72 beats per minute.
Respiratory rate: The number of breaths per minute, counting one inhalation plus one exhalation as one breath; adult reference ranges are often quoted as about 12 to 20.Example: 8 breaths in 30 seconds is 16 per minute.
Systolic and diastolic pressure: The first is the arterial pressure when the ventricles contract; the second is the pressure while they relax. Recorded as one over the other in mmHg.Example: In 118/76, 118 is systolic and 76 is diastolic.
Pulse pressure: The difference between systolic and diastolic blood pressure.Example: 120/80 mmHg gives 120 - 80 = 40 mmHg.
Mean arterial pressure: The average arterial pressure over one cardiac cycle, commonly estimated as (systolic + 2 x diastolic)/3.Example: 120/80: (120 + 160)/3 = 93.3 mmHg.
Oxygen saturation (SpO2): The percentage of hemoglobin carrying oxygen, estimated non-invasively by a pulse oximeter.Example: A reading of 97% means about 97% of the hemoglobin measured is oxygenated.
Celsius and Fahrenheit conversion: F = C x 9/5 + 32 and C = (F - 32) x 5/9.Example: 37.0 C = 98.6 F; 101.3 F = (101.3 - 32) x 5/9 = 38.5 C.

Units and dosage arithmetic

Metric mass conversions: 1 g = 1000 mg and 1 mg = 1000 mcg (micrograms); moving down a unit multiplies by 1000.Example: 0.25 g = 250 mg; 0.5 mg = 500 mcg.
Kilograms and pounds: 1 kg is about 2.2 lb; divide pounds by 2.2 to get kilograms.Example: 154 lb / 2.2 = 70 kg.
Desired over have formula: Amount to give = (dose ordered / dose on hand) x the quantity that the dose on hand comes in.Example: Practice: 500 mg ordered, supply 250 mg per 5 mL: (500/250) x 5 = 10 mL.
Weight-based dose calculation: Multiply the per-kilogram amount by body weight in kilograms to find the total amount.Example: Practice: 15 mg/kg for a 20 kg child = 15 x 20 = 300 mg.
Solution concentration: Amount of drug per unit volume, often mg/mL; found by dividing the drug amount by the total volume.Example: 2 g (2000 mg) in 100 mL = 20 mg/mL.
Percentage solution: Grams of solute per 100 mL of solution (weight/volume).Example: 0.9% saline has 0.9 g per 100 mL, which is 9 g per litre.
Ratio strength: A concentration written as 1 part solute to a number of parts solution, in g per mL.Example: 1:1000 means 1 g in 1000 mL = 1 mg/mL.
IV flow rate in mL/h: Total volume divided by total time in hours, as set on an infusion pump.Example: Practice: 1000 mL over 8 h = 125 mL/h.
Drip rate in drops per minute: (Volume in mL x drop factor in gtt/mL) / time in minutes, rounded to a whole drop for gravity sets.Example: Practice: 1000 mL x 15 gtt/mL / 480 min = 31.25, rounded to 31 gtt/min.
Infusion time: Total volume divided by the flow rate gives how long the bag will run.Example: 500 mL at 100 mL/h takes 5 h.
Body surface area (Mosteller): An estimate of body surface in m^2: square root of (height in cm x weight in kg / 3600).Example: 170 cm and 70 kg: sqrt(11900/3600) = sqrt(3.306) = 1.82 m^2.
Leading and trailing zeros: Always write a zero before a decimal point for values under 1, and never write a zero after a decimal point following a whole number, so the dose is not misread.Example: Write 0.5 mg, not .5 mg; write 5 mg, not 5.0 mg (which can be misread as 50).
24-hour clock: Time written from 0000 to 2359 without a.m. or p.m., widely used in health records to avoid ambiguity.Example: 1:30 p.m. is 1330; 12:15 a.m. is 0015.
Intake and output: A record of all fluids taken in (oral, IV, tube feeds) and lost (urine, drainage, emesis) over a period, in mL.Example: Practice: intake 1500 + 500 = 2000 mL, output 1700 mL: balance +300 mL.