Principles of phlebotomy and intravenous therapy

47. Principles of phlebotomy and intravenous therapy

intravenous cannulation


Considerations for the childbearing woman321


Choice of site322

Preparation 322

Asepsis and use of standard precautions322

Choice of equipment322


Ongoing care324


PROCEDURE: intravenous cannulation 324

Removing a peripheral cannula325

PROCEDURE: removal of a peripheral intravenous cannula 325

Role and responsibilities of the midwife326


Self-assessment exercises326


Having read this chapter the reader should be able to:

• discuss the indications for cannulation

• describe how the site is selected and the equipment chosen

• describe a safe cannulation technique

• describe the correct removal of an intravenous cannula

• summarise the role and responsibilities of the midwife.

As one of the vascular access devices, peripheral intravenous cannulae (PIC) are commonly sited and utilised in midwifery care. A peripheral cannula is sited into a vein for the purposes of infusing fluids or administering medicines via the intravenous route. Performing the skill requires training, supervised practice and ongoing maintenance of the skill. Depending on local protocol, cannula insertion is often only undertaken by qualified staff. PICs feature highly in the nursing and midwifery literature partly because of the risks of localised and systemic infection from their incorrect insertion, use or removal. This chapter reviews the skills of siting and removing a PIC, along with the role and responsibilities of the midwife.

Considerations for the childbearing woman

The additional blood volume in pregnancy and higher body temperature usually mean that the veins are prominent and are therefore easier to gain access to. PICs should only be inserted when there is a clinical indication, and it should be removed as soon as that aspect of care is completed. Undertaking an assessment prior to insertion of a cannula aids the process and reduces the risks. This includes assessment of the woman – previous experiences, age, health, informed consent, suitable site, known allergies – as well as considerations regarding the nature of the medication to be administered and for how long (Lavery & Smith 2007).

Choice of site


Venous access is improved if the practitioner and woman are relaxed and if certain physical measures are undertaken. A tourniquet should be placed 7–8 cm above the chosen site, heat may be applied (heat pack or warm water), gravity or vein filling may be utilised (clenching/unclenching fist) and gentle tapping or stroking the vein may increase its prominence (Dougherty 2008a). If indicated, topical analgesia may be used, but (depending on type chosen) needs 1–2 hours to be effective. A small amount of local anaesthetic such as lidocaine may be injected intradermally (see Chapter 20) at the proposed puncture site. This needs only 3–5 minutes to take effect.

Asepsis and use of standard precautions

Strict asepsis is indicated for the insertion and ongoing use of a peripheral intravenous cannula. All equipment should be sterile and for single use only, a sterile dressing pack and sterile gloves are used. Other personal protective equipment (PPE) includes the use of an apron. All sharps should be disposed of at the point of use in a portable sharps box. If continual use of a PIC is needed it should be renewed after 72–96 hours.

Skin cleansing should be undertaken using either 2% chlorhexidine or 70% alcohol (Dougherty 2008a). Gentle friction is necessary for at least 30 seconds, in a circular motion from centre to periphery. A rapid ‘one wipe’ of the skin merely disturbs the skin flora. The skin should then air dry for up to 1 minute, the vein should not be repalpated once the skin has been cleansed.

Jun 18, 2016 | Posted by in MIDWIFERY | Comments Off on Principles of phlebotomy and intravenous therapy
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