Chapter 13: Diagnostic tests
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Clinical governance
The practitioner must document their action in the patient's case notes and report the procedure, including assessment of the patient and any complications with the procedure itself. Any identified complications must be reported to a doctor as soon as practically possible. Practitioners are required to demonstrate knowledge of potential dangers and complications associated with the procedure. In addition, the practitioner must demonstrate knowledge of the signs and symptoms of associated complications, and be able to identify appropriate actions to safeguard the patient. Practitioners must undertake the role with due reference to the NMC Code (NMC [165]).
Competencies
Staff who undertake arterial puncture must be competent to do so. Each practitioner must be able to perform the relevant procedure in accordance with the trust policy or guidelines. Practitioners should not attempt arterial puncture more than twice on the same patient and must refer to a more experienced practitioner when practice limitations are recognized. See also Chapter c17: Vascular access devices: insertion and management.
Risk management
Sampling from arterial devices is risky and should only be done by competent, trained staff. Trusts should raise awareness of risks and review local guidelines. These should include criteria for requests for blood gas analyses, sampling technique, monitoring and interpretation of results (including unexpected results) (NPSA [168]; see also Chapter c17: Vascular access devices: insertion and management).
Arterial infusion devices must be clearly identified. This means labelling or using specifically marked devices (O'Hare and Chilvers [173], Osborne [174]). Any infusion (or additive) attached to an arterial device must be prescribed and checked before administration. Further checks should be made at regular intervals and key points (such as shift handover). Staff should use only sodium chloride 0.9% to keep devices open. Labels should clearly identify the contents of infusion bags, even when pressure bags are used (NPSA [168]).
To minimize the risks, clinical staff should ask themselves the following questions (NPSA [168]):
- Have I recorded the clinical reason for inserting this device?
- Is it clearly marked as an arterial device?
- Do I need to take this sample?
- Do I know how to do this safely (e.g. removing air from sample)?
- Have I picked the right infusion fluid bag? Did someone else check this?
- Can the label be seen, even if pressure bags are used?
- Is the reading from the sample within the expected range? Could it have been contaminated?
