18.2 Safe Medication Administration: The Rights, Dose Calculation & Error Management

18.2 Safe Medication Administration: The Rights, Dose Calculation & Error Management

CPCF Appendix A foundational knowledge #5 names, as examinable content, the "rights" of medication administration, dosage calculation for desired effect, patient and supply preparation, quantity measurement, and procedures related to medication administration errors. Medication error is among the most common causes of preventable patient harm in health care, and the prehospital environment — poor lighting, movement, noise, time pressure, single-operator checking — is uniquely hostile to accurate drug administration.

The Rights of Medication Administration

The classic five rights have expanded as error analysis has identified new failure modes. Different services teach different lists; what the examination tests is that you check them all, every time, without exception.

The Three Label Checks

Read the label three times: when you take the container from the kit, when you draw up or prepare the dose, and immediately before administration. This is not ritual — it is the control that catches the substitution error that happens between selecting and giving.

Check concentration separately from drug name. Epinephrine 1:1,000 and 1:10,000 are the same drug in the same kit at a tenfold concentration difference, and confusing them has killed patients. Also check the expiry date and inspect the solution for discolouration, particulate matter, or a damaged container.

Dose Calculation

Three formulas cover essentially all prehospital calculation.

1. Volume to draw up from a concentration:

Volume (mL) = Desired dose / Concentration on hand (per mL)

Example: Give 0.3 mg of epinephrine 1:1,000. The concentration is 1 mg/mL. Volume = 0.3 mg / 1 mg per mL = 0.3 mL.

2. Weight-based dosing:

Total dose = Dose per kg  x  Patient weight (kg)

Example: Give 0.01 mg/kg of epinephrine to a 12 kg child. Dose = 0.01 x 12 = 0.12 mg. At 1 mg/mL that is 0.12 mL — and note the maximum single dose of 0.3 mg is not exceeded.

3. Ratio concentrations: a ratio expresses grams of drug per millilitres of solution.

1:1,000   = 1 g in 1,000 mL   = 1,000 mg in 1,000 mL  = 1 mg/mL
1:10,000  = 1 g in 10,000 mL  = 1,000 mg in 10,000 mL = 0.1 mg/mL

Percentage concentrations express grams per 100 mL:

Dextrose 10% (D10W) = 10 g per 100 mL = 100 mg/mL
Dextrose 50% (D50W) = 50 g per 100 mL = 500 mg/mL
Lidocaine 2%        = 2 g per 100 mL  = 20 mg/mL

Unit Conversions You Must Do Without Hesitating

1 g   = 1,000 mg
1 mg  = 1,000 mcg
1 L   = 1,000 mL
1 kg  = 2.2 lb        (pounds / 2.2 = kilograms)

Never dose from a weight in pounds. Convert first, and say the conversion out loud.

Estimating Paediatric Weight

Where the caregiver does not know the weight, use a length-based resuscitation tape, which is more accurate than any formula and also gives drug doses and equipment sizes directly. Age-based formulas are a fallback only, and every estimate must be sanity-checked against the child in front of you.

[!CAUTION] Sanity-check every result before you give it. A calculated dose that requires drawing up 14 mL from a 1 mL ampoule, or that exceeds the adult dose in a child, or that is ten times the number you expected, is a calculation error until proven otherwise. The most common calculation error is a factor of ten from a misplaced decimal or a missed unit conversion — which is why the trailing-zero and leading-zero rules in Section 17.1 exist.

Preparation, Verification and Administration

1. Confirm the indication against the directive and the patient's presentation, and confirm there is no contraindication. Ask about allergies before, not after.
2. Obtain informed consent where the patient has capacity — explain what the drug is, what it should do, and the common and serious adverse effects (indicator H3.3).
3. Prepare in a controlled space. Stop the vehicle if that is what it takes to draw up a critical drug accurately.
4. Independently verify with your partner wherever a second clinician is present: state the drug, concentration, calculated dose, volume, and route aloud, and have them confirm against the label and the directive. Independent double-checking is the single most effective control against dosing error.
5. Administer, observing the correct technique for the route (Section 18.3).
6. Reassess for the intended effect and for adverse effects at an interval appropriate to the drug's onset.
7. Document immediately — drug, concentration, dose, route, site, time, who administered, the indication, the consent, and the response. Never document before administering.
8. Retain and account for the packaging, particularly for controlled substances, and follow your service's narcotic accountability procedure exactly.

High-Alert Medications

Certain drugs cause disproportionate harm when given in error and warrant a double check every time regardless of familiarity: epinephrine (two concentrations, two routes, two indications), opioids, benzodiazepines, insulin, anticoagulants, concentrated electrolytes, and concentrated dextrose.

When an Error Occurs

CPCF #5 names procedures related to medication administration errors, and competency A2 and indicator B3.2 govern what follows. The examinable sequence:

1. Patient first. Stop the administration, assess and treat the consequences, provide any antidote or supportive care within your directive, and escalate to medical direction or a higher level of care. Everything else waits.
2. Report immediately — to your partner, to medical direction, to the receiving clinician at handover, and through your service's incident-reporting process. An error concealed at handover becomes a second, larger error.
3. Disclose to the patient. Indicator B3.2 requires paramedics to disclose harmful patient safety incidents accurately and appropriately to patients, families, and those in the circle of care, and indicator A1.2 requires recognizing and responding to ethical issues. Disclosure is an obligation, not a discretionary courtesy.
4. Document factually. Record what was given, when, by what route, and the patient's response, in objective language. Document the clinical facts in the patient care record; the analysis of why it happened belongs in the incident report, not in the clinical record.
5. Preserve the evidence — keep ampoules, packaging, syringes, and the device.
6. Participate in the review. A just-culture system exists to find the system fault: look-alike packaging, an ambiguous directive, poor lighting, interruption, fatigue. Indicator G3.2 requires supporting a culture that promotes practice improvement and patient safety, and A1.5 requires demonstrating a commitment to patient safety and quality improvement.

[!IMPORTANT] The instinct to minimize or conceal a medication error is the most dangerous response available. Competency A2.3 makes you accountable for all decisions and actions; A2.1 requires trustworthiness. On the examination, any option involving not disclosing, not reporting, or "monitoring quietly to see whether there is any harm" is wrong.