NEO-SOP-002: Weight-based medicine dosing for neonates and infants

Standard operating procedure (SOP) · NEO-SOP-002 · Version 0.1 · Draft for local review

Supports: 37.1

1. Purpose

To make sure every medicine given to a neonate or infant is dosed for the child's current weight and age, that the calculation is correct and independently checked, and that every dose is recorded. The aim is to prevent dosing errors, which are among the most frequent causes of serious harm in neonatal care (37.1).

2. Scope

3. Definitions

4. Background

Neonates and infants differ from adults and older children in how they absorb, distribute, break down and excrete medicines. Liver enzymes and kidney function are immature, particularly in preterm infants, and body water and protein binding change in the first weeks of life. Many medicines have no licensed neonatal dose, so prescribers use reference sources that give doses by weight and postmenstrual or postnatal age.

Weight changes quickly in the first days of life, so a birth weight may not be the right weight for dosing. Errors most often come from using an old weight, mis-placing a decimal point, confusing units, or misreading a concentration.

5. Responsibilities

6. Materials and equipment

• Calibrated neonatal scale, checked and recorded at least monthly (or per manufacturer's instructions).
• Current approved neonatal reference: the BNFc or the national neonatal formulary, with the unit's local neonatal dosing guide.
• Dosing chart with fields for weight, date and time, prescribed dose in mg/kg and mg, volume, concentration, and the checks.
• Calculator approved for clinical use.
• Standard list of concentrations stocked in the unit. Stock concentrations that are not on the list are not used without pharmacy advice.
• Labels for prepared medicines with the patient identifier, medicine name, dose in mg, volume, concentration, and preparation date and time.
• Infusion pumps with dose-error reduction software where available.

7. Safety

Write numbers so that the risk of misreading is removed:

• Write a leading zero before a decimal point (write 0.5 mg, not .5 mg).
• Never write a trailing zero after a decimal point (write 5 mg, not 5.0 mg).
• Write 'microgram' in full, not 'mcg' or 'µg', because the abbreviations are easily confused with 'mg'.
• Do not use 'U' for units or 'IU' for insulin units. Write 'units'.
• Express every dose in mg/kg and in mg, and the volume in mL, on the same line.
• Check that the concentration on the label matches the concentration in the prescription before drawing up.

8. Before you start

1. Check the patient's identity using two identifiers (for example hospital number and date of birth).
2. Check that a measured weight is available and no more than 24 hours old. If not, weigh the infant before calculating.
3. Record gestational age at birth and current postnatal age, and calculate postmenstrual age.
4. Check allergies, feed status, current medicines and the most recent renal and liver results where relevant.
5. Check the reference for the medicine, the dose per kg, the maximum single dose and the maximum daily dose for this age.

9. Procedure

9.1 Prescribing

1. Weigh the infant on the calibrated scale and record the weight in kg to two decimal places, with date, time and scale.
2. Write the prescription in mg/kg and in mg, state the volume and concentration, and state the frequency and duration.
3. Check the dose against the reference for postmenstrual and postnatal age. Adjust for prematurity, kidney or liver impairment, and interacting medicines.
4. Confirm the dose is within the maximum single and daily dose. If it is above a maximum, do not prescribe it without discussion with the pharmacist and the consultant.

9.2 Verification and preparation

1. For high-alert medicines and all infusions, the pharmacist verifies the prescription before the first dose and after any change.
2. The nurse preparing the medicine calculates the volume independently and compares it with the prescription.
3. A second registered professional repeats the calculation without seeing the first result. Both results must match before the medicine is given.
4. Label the prepared medicine with all the information in Section 7 and the patient identifier. Do not give a medicine that has no label or an unclear label.
5. If the two calculations do not match, stop. Recalculate with the prescriber and pharmacist, and record the outcome.

9.3 Administration

1. Use the five checks at the bedside: right patient, right medicine, right dose, right route, right time.
2. For pump infusions, check the programmed rate, the concentration and the dose per hour against the prescription, with the second person.
3. Record the dose given, the time, the route, the nurse's name and the checks completed on the chart.
4. If a dose is not given, record the reason and inform the prescriber.

9.4 After the dose

1. Monitor the infant's response and any adverse effects as set in the drug's protocol.
2. Report any dosing error, near miss or unexpected effect under the incident reporting policy within 24 hours.

10. Decision points

11. High-alert medicines in the neonatal unit

The following always need a pharmacist verification and an independent double check before the first dose and before each change of dose: infusions and concentrated preparations; opioids; anticoagulants; insulin; concentrated potassium and electrolytes; neuromuscular blocking agents; antiseizure medicines given intravenously; and any medicine on the unit's local high-alert list.

12. Special situations

• Resuscitation: use the unit's resuscitation dosing card. Still record the weight used and the dose given. Complete the calculation and check after the immediate response.
• Very low birth weight (under 1,500 g): doses are usually more sensitive to small errors, so the pharmacist check is required for all doses.
• Transfers: the sending team's dose is checked against the receiving unit's reference and weight on arrival. Do not assume a dose is correct because it was given before transfer.
• Breastfeeding and breast milk: check medicine compatibility before giving a medicine with breast milk and record the decision.
• Weight loss or gain in the first week: re-weigh if the infant has lost or gained more than 10 percent from the birth weight, and recalculate the dose.

13. Escalation

• Prescription unclear or conflicting: call the prescriber immediately. Do not give the medicine until it is clear.
• Dose above a maximum, or a suspected error: stop the process, call the on-call neonatologist and the pharmacist.
• Infant deteriorating after a dose: follow the unit's deterioration escalation policy and inform the consultant.
• Harm or near miss: report under the incident policy within 24 hours and inform the unit manager. Serious incidents follow INC-SOP-001.

14. Monitoring

The unit manager carries out a monthly audit of 20 randomly selected neonatal prescriptions, or all if fewer, and reports results to the neonatal governance meeting each quarter.

15. Records

• Weight chart with date, time and scale used.
• Prescription and dosing chart with the calculation, the checks and both signatures.
• Administration record with time, route and nurse name.
• Pharmacist verification record for high-alert medicines and infusions.
• Incident and near-miss reports.
• Records are kept for the period required by national law and local policy.

16. Training

All staff who prescribe, prepare, check or give medicines to neonates or infants complete a dose calculation assessment at induction and every year. The assessment includes at least ten calculations from realistic neonatal scenarios. A score of 100 percent is required on the calculation section. Staff who do not pass receive supervised practice and are reassessed within four weeks.

17. Related documents

18. Evidence

This SOP is based on the reference sources listed below and on the requirement of criterion 37.1 of the ASF standards. The local neonatal dosing guide must be checked against these sources at each review, and the review date recorded in the change history.

E-learning for this document

• No course linked yet. Dose-calculation and medication-safety courses are to be requested from the academy (see the Standard 37 request list).

References

1. British Medical Association and Royal Pharmaceutical Society. British National Formulary for Children (BNFc). Current edition.
2. Institute for Safe Medication Practices (ISMP). List of Error-Prone Abbreviations, Symbols, and Dose Designations. Current edition.
3. The Joint Commission. National Patient Safety Goal NPSG.03.06.01: Maintain and communicate accurate patient medication information. Current edition.
4. Local neonatal dosing guide and national neonatal formulary (to be inserted by the unit at adoption).

Change history