Nasogastric tubes are thin polyurethane tubes that extend from the nose to the stomach and allow administration of artificial feeding and hydration as well delivering drugs to patients who are unable to swallow safely. This may occur as a result of critical illness and being unconscious or due to neurological illnesses such as after a stroke, in addition to situations where the patient is taking a sup-optimal oral intake, in spite of an intact swallow mechanism.
There are about 800,000 tubes used annually in the UK, usually placed at the bedside by trained nurses on the recommendation of the clinical team responsible for the patient. They can be kept in place for 6-8 weeks, beyond which there are risks of complications, such that conversion to a more permanent gastrostomy feeding route (PEG) should be considered.
Although complications from the placement of an NGT tube are rare, when they do occur, they can have devastating consequences. The most serious harm from NG tube placement arises from misplaced NG tubes, when the tip is lying in the lungs or the pleural space, leading to pneumothorax, pneumonia and feed empyema, which can be fatal if not recognised early. This occurs in 1-3% of blind NG tube placements. Use of misplaced nasogastric tubes was first recognised as a patient safety issue by the National Patient Safety Agency (NPSA) in 2005 and three further alerts were issued by the NPSA and NHS England between 2011 and 2013. Between 2005 and March 2010, 21 deaths and 79 cases of harm were reported. Between 2011 and March 2016 it is reported that 32 deaths and 95 cases of harm occurred due to misplaced NG tubes.
The commonest error, according to clinical reviewers for NHS Improvement, relates to misinterpretation of x-rays by medical staff who did not appear to have received the competency-based training required by the 2011 NPSA alert. Other error types involve nursing staff and pH tests, unapproved tube placement checking methods, and communication failures resulting in tubes not being checked.
Because of the preventable nature of harm, in 2011 misplaced nasogastric tubes were confirmed by the Department of Health in England as a ‘never event’, one of a restricted list of “serious avoidable events that could incur financial penalties for providers.” As a never event, health care practitioners and Trusts need to ensure that correct techniques are followed in the placement of the NG tube. All misplacement incidents must be reported locally as well as nationally to the NRLS (National Reporting and Learning System, a central database of patient safety incident reports).
The only valid techniques to confirm correct tube position in the stomach are aspiration of contents from the tube with accurate pH testing using recommended pH paper that is CE marked (not litmus paper as this is not sensitive enough to differentiate between bronchial and gastric secretions) or a chest x-ray. pH levels less than or equal to 5.5 are adequate to confirm that the tip of the tube is in the stomach. pH readings that are above 5.5 need to be repeated or require the alternative confirmatory test of a CXR.
Before placing a NG tube and in order to avoid complications, the team should always ask themselves the following:
About the Author
Dr Steven Mann is a Consultant Gastroenterologist at Barnet Hospital, Royal Free London NHS Foundation Trust.
Dr Mann also provides medico-legal opinion and can be contacted by emailing firstname.lastname@example.org