Infusing by gravity

Intermittent infusions are administered over a set time period, either as a one-off dose or at repeated time intervals. Best practice is to administer these medicines via an infusion pump to accurately control the rate at which the infusion is delivered. However, these are not risk free, in part due to user error. Standardisation and training can minimise the risks.

Organisations need to consider where their biggest risks are, acknowledging that this may vary between internal departments, depending on equipment, staff experience and training.

We have produced some recommendations to help identify the risks associated with infusion by gravity, along with practical considerations to ensure safe practice within your organisation.

Choose the most appropriate method

There are situations where administering by gravity may be the most appropriate method of administration, including times when infusion delivery devices are not readily available. This might be as a result of high capacity in organisations where demand outweighs supply, or supply shortages of pumps or associated equipment.

In these situations an individual risk assessment is required before determining if the intravenous medication can be delivered via gravity.

Review the prescription

Assess the number of intravenous medicines prescribed. Consider an oral switch for those medicines that can be safely and effectively administered this way.

Some medicines can be administered as a bolus injection. The individual monographs in the BNF, SPC and Medusa give further details.

For some medicines, the rate of administration does not need to be tightly controlled. Consideration may be given to whether these can be safely infused under gravity.

Risks associated with infusion under gravity

It is essential that a clinical review is undertaken before administering a medicine under gravity, considering the potential risks to the patient.

Infusion rate considerations

When infusing a medicine under gravity, the main risks occur if the medicine is infused at a rate faster or slower than intended or at a variable rate.

Slower than intended

Infusing a narrow therapeutic index medicine at a rate of administration slower than intended, may mean the drug may not reach the peak concentration necessary for action. This can lead to reduced clinical effectiveness.

Faster than intended

Infusing a medicine faster than intended may increase the chance of adverse effects. This risk is greater for medicines with known infusion rate-related adverse effects.

A medicine infused too quickly can also put the patient at risk of fluid overload, especially for those patients requiring a strict fluid balance.

Factors affecting suitability for infusion under gravity

The following factors should be considered before deciding to administer a medicine infusion under gravity.

Equipment factors

Devices

Review the number of infusion devices available. Consider infusing medicines consecutively where the regimen permits to minimise the number of infusion devices required per patient.

Giving sets

Ensure there are enough giving sets (infusion lines) available and consider sourcing alternatives if needed.

Medication factors

The following factors may make a medication less suitable for infusion under gravity:

• adverse reactions related to the rate of infusion, for example vancomycin
• medicines with a higher risk of hypersensitivity reactions, for example iron infusions
• medicines that are adjusted according to patient response, for example aminophylline
• infusions required to be delivered at a controlled rate, for example units/kg/hr with heparin

Patient factors

The following factors make the patient less suitable to be able to receive medicines under gravity:

• a history of infusion related adverse reactions
• the need for a strict fluid balance
• extremely unwell patients

Record and review

There are a number of ongoing considerations for infusions delivered under gravity:

• ensure the prescription accurately reflects the intended method of administration
• appropriate monitoring of the patient should be undertaken at regular intervals
• potential adverse effects should be reported
• regular re-evaluation to confirm that infusion under gravity is still appropriate

Governance considerations

The following organisational factors should be considered when permitting the use of infusions under gravity.

Collaboration

A number of stakeholders in an organisation should be involved if there is a need to use gravity infusion to administer medicines. Good collaboration ensure timely communication across an organisation.

Relevant stakeholders usually include:

• clinical pharmacy team
• Medication Safety Officer (MSO)
• Medication Device Safety Officer (MDSO)
• equipment library
• procurement team
• clinical site managers (or equivalent)
• relevant nursing managers

Documentation

The following points demonstrate good practice for managing documentation:

• prescriptions should give detailed information on how the medicine is to be infused
• administration records should be an accurate reflection of how the medication was infused
• expected practice should be documented in the appropriate policies

Communication

Organisations should ensure there is a communication plan in place to inform staff of a change in infusion practice. This includes when infusions devices or equipment may not be available for prolonged periods, such as during a pandemic.

In all circumstances, organisations should ensure:

• staff are aware of any relevant policies
• staff are informed of any changes to practice in a timely fashion

Information and resources

The following information resources for specific medicines are recommended:

• British National Formulary
• Summary of Product Characteristics
• Medusa the NHS Injectable Medicines Guide

The National Infusion and Vascular Access Society has additional information.

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