BLENDED DIET FOR TUBE FED CHILDREN IN THE UK
Addressing concerns about tubing pressures
Parents and professionals may have concerns about how much pressure can be exerted on the tubing and equipment used in blended diet or any tube feeding. However the tubing is very robust and has been tested extensively by the manufacturers.
I've heard of some parents being told the balloon will burst, or the tubing will burst which is very very unlikely because the pressures needed to generate that much force is not usually possible. I've looked at Corflo's website and there is a very informative section there about the testing they have done on pressures. CORFLO Enteral Feeding Tube - Pressure When Using Syringes.
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This is the extract which is most important to us, although the actual link has been removed. Basically it is saying the pressure in the tubing only would need to be twice the pressure in a car tyre before it bursts. Always remember tubes clog quite often with medication anyway and the tube manufacturers expect you to push and pull quite firmly to dislodge the clog. It does not refer to the button or the bit that sits inside and outside of the abdomen on a PEG long tube, as these have smaller connections and are usually made of much softer silicone and also have delicate valves in the case of buttons.
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CORPAK MedSystems conducted a study to determine the pressure inside its feeding tubes using different syringes at varying force and their effect on the strength of the Feeding Tubes. Three tests were done on five different size tubes; 5 Fr., 6Fr., 8 Fr., 10 Fr., and 12 Fr., using 6 different syringes; 3ml, 6ml, 10ml, 20ml, 30ml, 50/60ml. In the first test the syringe injected water and the time was checked for bursts. In the second test the syringe evacuated air and the tubes checked for collapse. The third test involved evacuating air from the tubes. In each test the tubes awere occluded 3 inches from the top to simulate a clogged tube.
The result of the first test was that none of the tubes burst. Each tube withstood an internal pressure of 80psi or higher with one or more syringes. Pressures of up to 100 psi were recorded. The first test provided evidence of the known fact that smaller syringes produce greater pressures using less force than larger syringes. However, smaller syringes are of less volume, so a 3ml syringe would be very unlikely to burst a tube. Larger syringes could burst a tube, but the force required would be tremendous.
Whilst performing the test, it was noted that the syringe most at risk for bursting the tubes is the 6ml model, which produced 100psi at 19.4 lbs force on the plunger. It is unlikely that a user could provide this amount of force.
The second test showed a general trend that the smaller syringes can create higher negative pressure at lesser forces than the large syringes.
The third test involved evacuating air from the tubes. The forces required to evacuate air from the tubes were small enough that a person, with some effort, could pull the plungers out of each syringe. A bigger syringe would be more likely to collapse the tube than a small one. As the second test confirmed, however, the tubes did not collapse when the syringe plungers were pulled to their full position. It therefore seems unlikely that, in normal clinical use, the feeding tubes would burst or collapse because typically a person would not be able to exert enough force on any syringe to burst them. If the tube was clogged, a user pushing or pulling with force would realise that there is an obstruction and stop before the tube burst or collapsed.
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However, it is very important to take care with a blocked NG tube or BD fed via a NG tube. If it ever did split it could cause a catastrophic leak of food into the lungs which is dangerous for the child and would cause a serious pneumonia. Attempt to disperse any blockage as shown by your health care professional safely, or simply change the tube.
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Testing Mic-key buttons for pressures
Tube pressure resistance is obviously very high but the weak link is the buttons themselves and the connections. Buttons are usually made of silicone or partly so, and have valves. The manufacturer of Mic-key buttons (Halyard Health now rebranded as Avanos) had a facebook page and were very helpful, as are most American companies and there is no reason to think their positive stance on blended diet has changed. I asked them about the pressures in the button and they replied 7.25 psi which, although considerably less than the plastic tubing, is enough to feed BD through at a much thicker consistency than formula without undue pressure. Again they have to be able to withstand a certain amount of pushing and pulling if blocked. I make my blends to a thick batter consistency.
The Plastics manufacturers and Blended Diet
The EPSG (Enteral Products Safety Group) represents UK plastic tube manufacturers and suppliers. Initially they were very unsupportive of Blended Diet food being used with the tubing they supplied. Stating clearly they did not support BD and it should not be used with their products. This statement and stance was taken up by many dieticians at the time and used to dissuade parents from feeding their children BD. It caused problems for everyone as people and supportive dieticians were actively going against this Safety Group.
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However, even this rigid stance has now softened with a revised statement issued in January 2022. Their statement now says
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Enteral Products Safety Group (EPSG) Statement: Liquidised Food
Updated January 2022
Due to increasing enquiries from patients and clinicians regarding blended food, the EPSG recommends that any patient/carer wishing to administer liquidised food via their enteral feeding device should do so with a shared decision-making approach, as advocated in the BDA practice toolkit; The use of blended diet with enteral feeding tubes. Therefore, an individualised enteral feeding risk assessment should be carried out by a healthcare professional, in line with their Trust or Clinical Commissioning Group (CCG) risk assessment policy and in line with the suggested good practices within the BDA practice toolkit. NICE guidelines recommend that wherever possible, pre-packaged, ready-to-use feeds should be used in preference to feeds requiring decanting, reconstitution or dilution. Some pre-packaged tube feeds contain food derived ingredients which may be of preference for those wishing to use alongside a blended diet.
In addition to the feed, some enteral feeding devices may also be suitable for use of liquidised feeds, but only under the advice of a healthcare professional. The EPSG recommends that the device instructions for use (IFU) should always be referred to.
Avanos, who make the Mic-Key button and AMT who make the mini button are both supportive of the use of blended food via their products provided adequate care and training is given.
AMT who make the mini button say in the link ' A G-Tube or a GJ-Tube is a convenient and effective means for delivering nutritional formulas to the body. These nutritional formulas are either commercially available or homemade using a food processor'.
The Term Licensed
You may hear the term 'not licensed' in the UK in relation to putting food through the tubing and the buttons. Just to reiterate. Food is not licensed because it is not tested not because it is unsafe.
Its worth remembering that nothing can be tested on children because it is unethical as they can't consent. Medications like trihexiphenidyl are given but it is described as off license.
Most importantly for us, and as one of our blenders told me, her consultant gastro told her that many peices of equipment throughout the NHS are used for other purposes. So to give food down a plastic tubing as opposed to formula, is very minor.
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