Medical device safety

This page is part of the wider ‘enduring standards that remain valid from previous patient safety alerts‘ set of webpages.

Medical device-related incidents account for about 2% of reported incidents. Guidance and resources from national organisations, such as the MHRA and the MDSO network, provide advice on purchasing for safety and safe maintenance, and emphasise the clear overriding principle that staff should be trained and competent to use all medical devices introduced into clinical practice.

Enduring standards from past alerts that remain valid are:

  • Identify a medical device safety officer (MDSO) and ensure contact details are kept up to date with the MHRA’s CAS team. For more information see: Linking with national systems – Nominated safety officers/safety specialists.
  • Aspects of nasogastric tube placement checks considered to be safety-critical enduring standards were set out in a resource set linked to a 2016 alert; these actions replaced those in multiple alerts issued previous to this.
    • Do not use the ‘whoosh test’ or ‘bubble test’.
    • Do not test aspirate using blue litmus paper.
    • Do not interpret absence of respiratory distress or the appearance of aspirate as an indicator of correct positioning.
    • Nasogastric tubes should only be placed when senior support for placement and placement confirmation is readily available
    • pH in the ‘safe range’ or x-ray are the only acceptable methods of confirming initial placement of a nasogastric tube.
    • pH in the ‘safe range’ of 1 to 5.5 can be used to exclude placement in the respiratory tract – the potential for local adaptation is outlined in the resource set.
    • Checking tube placement via x-ray includes confirming and recording in the patient record that any x-ray viewed was the most current x-ray for the correct patient, the four criteria for confirming gastric placement, and clear instructions as to required actions – see resource set for more information on the four criteria.
    • Nasogastric tubes are not flushed, nor are guidewires pre-lubricated, nor is anything introduced though the tube until initial placement has been confirmed.
    • Purchasing policies are revised and old stock systematically removed to ensure all:
      • pH test strips are CE marked and intended by the manufacturer to test human gastric aspirate.
      • nasogastric tubes used for the purpose of feeding are radio-opaque throughout their length and have externally visible length markings.
    • Any unused tubes identified in the lung are removed immediately, whether in the x-ray department or clinical area.
  • Pulse oximeters: a previous alert set out the requirement that organisations should ensure:
    • ongoing access to adult finger and ear probes in all clinical areas where oximetry is used (including the range required for babies and children where appropriate)
    • provide point-of-use reminders on why it is vital to use the correct probe for fingers and for ears, and for babies and children
    • provide point-of-use reminders on other factors that may interfere with the accuracy of the reading.


Go back to the main  ‘enduring standards that remain valid from previous patient safety alerts‘ webpage.