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:
- Is nasogastric feeding right for this patient? The decision to feed should be agreed by two competent professionals and recorded. If there are anatomical concerns about NG tube insertion such as a pharyngeal pouch or oesophageal stricture, x-ray guided NG tube will be safer.
- Does the NG tube insertion need to be done now? Risks are greater during the night.
- Am I competent to do this? Ensure you have had training in safe insertion and checking, including interpretation of x-rays.
- How can I check the right amount of tube has been inserted? Use “NEX” measurement (by placing exit port of tube at tip of Nose, stretching to Earlobe and then down to Xiphisternum) to guide insertion. The tube length should be confirmed and recorded before each feed to check it has not moved.
- Do I know how to test for correct placement? Do not flush tubes or start feeding until you can confirm by testing with quantitative pH indicator paper. It is essential to ensure that the nasogastric tube is in the stomach to prevent any complications. Some reports suggest staff believe it is acceptable to insert water or other fluid to ‘flush out some aspirate’. This is never safe to do.
- What is a safe pH level? Obtain a nasogastric aspirate (pH levels between 1 and 5.5 are safe). Double-check with another person if you are unsure. Always record the result and the decision to start feeding.
- When should I get an x-ray? If no aspirate can be obtained or the pH reading is above 5.5, request an x-ray specifying the purpose so the radiographer knows the tip of the NG tube should be visible.
- Fluid given via a tube is regarded in law as a medical treatment.
- Consent of a competent adult patient must be sought for any treatment, especially an invasive measure such as hydration or feeding via a tube, and refusal is binding.
- For an incompetent adult patient, the doctor undertaking care is responsible in law for any decision to withhold, give or withdraw a medical treatment. The doctor’s duty is to act in a way which he or she believes to be in the patient’s best interest. Before making a decision about starting, stopping or continuing treatment, the doctor should seek to ascertain the patient’s previously expressed views about the type of treatment he or she would wish to receive should the present state of incompetence occur. Full consultation with the family and the health care team is needed from the outset.
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
- Nasogastric Tube Errors. Casebook 2012; 20(3):10-12.
- National Patient Safety Agency (2005) Patient safety alert 05: Reducing the harm caused by misplaced nasogastric tubes. National Patient Safety Agency February 21 NPSA, London.
- National Patient Safety Agency (2011) Patient Safety Alert 2011/PSA002 Reducing the harm caused by misplaced nasogastric feeding tubes in adults, children and infants, NPSA London.
- National Patient Safety Agency Rapid Response Report: Harm from flushing of nasogastric tubes before confirmation of placement 2012.
- Good Practice Guideline. Safe Insertion and Ongoing Care of Nasogastric (NG) Feeding Tubes in Adults. National Nurses Nutrition Group, April 2016.
- Nasogastric tube misplacement: continuing risk of death and severe harm (2016). NHS/PSA/RE/2016/006. NPSA London.