Inappropriate placement of pulse oximeter probes

Patient Safety Update

Measurement of oxygen saturation, using a pulse oximeter probe during diagnosis and ongoing monitoring is a key component of the National Early Warning Score (NEWS2).

Oximeter probes can be single or multiple use and are designed to attach to specific parts of the body. Adult oximeter probes can be attached to either a finger or an ear, but are not interchangeable between these sites, while probes for babies and children need to be selected according to the patient’s weight.

If an oximeter probe intended for the finger is attached to the ear (or viceversa), or a probe intended for an adult is attached to a baby or a child (or
vice versa), it can produce a reading up to 50% lower or 30% higher than the real value.2,3,4 The clinical implication of an inaccurately high reading,
especially as part of NEWS2, is that staff may be falsely reassured about a patient’s condition, when in reality the patient is deteriorating, or may make an inappropriate intervention when in fact a patient is stable or improving.

NHS England's patient safety team was made aware that this issue in 2018 and issued the safety alert below.
Clinical staff are advised to re-read the alert and review their procedures for using the correct probes.

Jordan Nicholls
Patient Safety Integration Lead


Published 22nd December 2020