For a variety of reasons, including colic treatment or fluid and electrolyte supplementation, equine practitioners commonly pass a nasogastric (n-g) tube. Such a common practice is taken for granted yet may pose health risks to the veterinarian. Blowing in the tube is a common practice to assess correct esophageal placement, patency of the tube for gastric lavage, or to reflux gastric contents. A questionnaire sent to 123 European equine veterinarians queried how they handled the n-g tube when performing this procedure. The questionnaire aims to assess the risks of nasogastric intubation of horses by equine practitioners. [Drozdzewska K, Potocnik E, Schwarz B. Nasogastric Intubation as Health and Safety Risk in Equine Practice – A Questionnaire. Journal of Equine Veterinary Science 2020, vol. 88; https://doi.org/10.1016/j.jevs.2020.102951]
The objective in the questionnaire was to identify how many handle the n-g tube by mouth and how this affects human health and safety. Most practitioners questioned had extensive experience in equine practice: 39% had 1-5 years experience; 23.6% had 5-10 years; and 17% had worked in equine practice for longer than 20 years. Nearly 98.4% said they blow or suck on the end of the n-g tube with their mouth. Two male practitioners used an alternative method.
Results
Swallowing equine stomach contents or medications occurred in 67.2%. Aspiration occurred in 37.4%. This implies contact of these materials with mucous membranes and potentially the gastrointestinal mucosa. One question asked was if a veterinarian would use their mouth to handle the n-g tube for a horse with suspected poisoning. Nearly half responded that they would. If the horse was being treated with fever combined with diarrhea or reflux, 78% said they would handle the end of the n-g tube with their mouth.
Only a single practitioner claimed to sterilize the n-g tube after each use. About 27% said they disinfect the tube, and 71.5% simply wash the tube.
Subsequent Medical Issues
Despite the large number or respondents admitting to swallowing or aspirating stomach contents or medications, only eight (6.5%) of them developed subsequent medical issues. These include cough, pneumonia, fever, diarrhea, or side effects of zinc phosphide (rodenticide) inhalation that forms phosphine gas. Aspiration of mineral oil is fraught with the risk of serious pneumonitis. One respondent reported that a colleague developed MRSA from the procedure. Four noted roundworms in the n-g tube or in their mouth.
Notably, fewer experienced practitioners used the mouth during intubation of high-risk patients. More experienced vets also tend to disinfect or sterilize their tubes. Yet, the numbers doing so remain low.
Bacterial Transmission
The study clarifies that because not all tubes are disinfected appropriately, there is a risk of bacterial transmission to a practitioner handling the tube by mouth. Accidental swallowing or aspiration can also result in gastrointestinal infection. This is particularly true when treating a horse with Salmonellosis (symptomatic or asymptomatic) or Clostridia infection. Caution should be followed when intubating a horse with foul-smelling or bloody reflux. Transfer of MRSA from horse to human is also possible. This can potentially cause skin and soft tissue infection or sepsis, and/or cause the practitioner to be a MRSA carrier.
Suggestions to mitigate risk include gently lavaging the tube with a small amount of water to enable a siphon effect. Another option is to use a portable suction-generating device for this purpose.
Conclusion
In summary, there are risks of nasogastric intubation of horses for equine practitioners. Using the mouth to handle an n-g tube is a hazardous occupational practice. It has the potential for complications, some of which do not cause acute symptoms but nonetheless may be medically devastating. Caution should be taken with this procedure. Veterinarians should pay attention to proper hygienic management to appropriately disinfect n-g tubes after each use.
