Below is a sneak preview: an excerpt from Complete Tubefeeding (Everything you need to know about tubefeeding, tube nutrition and blended diets) , due to be published any day now.
1. A brief history of tube feeding
(actually it's a longer history than you might imagine)
“The need to avoid prolonged starvation in patients is well recognized.”
(from the introduction to the American Gastroenterological Association's official recommendations on the use of enteral nutrition.)
These days when we get a g-tube or other sort of enteral feeding device placed, we go to a modern shiny hospital with highly-trained staff, expensive hi-tech equipment and machines that go 'Bing!' Most tubes are placed in a sterile operating theatre with a surgeon and an anesthetist, maybe some radiological equipment, and all sorts of brilliant tools. The devices themselves are made of state-of-the-art materials; high grade flexible silicon and specialized plastics, and often have quite the sci-fi look about them. Then you will be introduced to the truly amazing advances in synthetic nutritional products – they come in a bewildering array of different types and brands for different patient profiles and needs and yes, they really are a product of the space age. So we tend to think that the miracle of tube feeding is a pretty recent development. Well, yes and no.
In fact, it seems using tubes for feeding patients goes back at least 3500 years to ancient Greek and Egyptian civilizations. Papyrus evidence suggests that Egyptian physicians used reeds and animal bladders to rectally feed patients things like wine, milk, whey, broth and so on to treat a range of complaints. Rectal feeding would remain the artificial feeding method of choice for many thousands of years because of the difficulties in accessing the upper GI tract without also killing the patient. Some things in medicine have hardly changed at all, as not killing the patient remains important to this day.
There are some reports of tube feeding in the 12th century but the acknowledged Western pioneer was a fellow called Capivacceus who in 1598 used a hollow tube with a bladder attached to one end, filled with some form of nutrient solution, down as far as a patient's esophagus. The beautifully named Aquapendente used a form of nasopharyngeal tube in 1617 – the forerunner of our NG tubes, but only going as far as the pharynx. A guy (they're all guys I'm fairly sure) called Von Helmont devised a flexible leather tube for feeding into the top of the esophagus in 1646, which must have been a pretty good improvement in patient comfort over things like hollow whalebone. Then in about 1710 it was suggested that such tubing might be used to reach all the way to the stomach.
For the rest of the 18th and the 19th centuries gastrointestinal feeding was practised here and there but I suppose due to the discomforts and difficulties of keeping a tube down someone's throat - or whatever other reasons - rectal feeding was a more widespread and accepted practice. Some of the oro- and naso-feeding contraptions were quite sophisticated, for example in 1790 a physician called Hunter was doing oro-gastric feeding using a whale bone covered in eel skin attached to a bladder pump to feed his nutrient solutions. He is reported as using mixtures of jellies, beaten eggs, sugar, milk and wine. Anyone who's had a naso-gastric (NG) tube as I have will tell you it's a pretty awful feeling thing, even worse I would imagine back then, using the sorts of materials available before high-tech plastics and silicone. But imagine an oro-gastric tube! This probably explains why it seems NG tubes increased in relative popularity for gastrointestinal feedings as time went on. These tubes still most often only extended down as far as the fauces (the narrow part past the back of the mouth towards the pharynx) and in the 1870 mixtures such as thick custard and mashed mutton were forced through these tubes, or combinations of warm milk, beef broth, eggs, and medicines appropriate to the symptoms of the patient.
These sorts of feedings weren't just for patients who couldn't eat, mind you: according to physicians such as Coulton naso-pharyngeal feeding was also inflicted upon 'fasting girls and spoilt children who, when ill, refuse food'. In addition to tubes, devices that looked a bit like a teapot with a very long spout were made to force-feed patients in mental institutions mixtures of milk, egg, beef tea and wine thickened with arrowroot.
When US President James Garfield was shot in 1881 he was kept alive a further 79 days by being rectally fed a blend of beef broth and whisky.
BONUS History Trivia: Alexander Graham Bell also devised a very early sort of metal detector to attempt to find the bullet inside the President, but it failed to work – it was reading the bedsprings instead, and as metal bed frames were very rare then, no-one at the time could work out why the device malfunctioned. PLUS: One of the doctors trying to save the President had the given name of 'Doctor”: Dr Doctor Willard Bliss.
Rectal feeding does (thankfully) seem finally to have gone out of fashion although I am told that some medical students these days, upon learning of things like James Garfield's ordeals discover all over again that colonic absorption is a very fast way to get drunk. Apparently. Don't try it though, OK? Even if you are in college.
But gastrostomy – inserting a tube through the skin directly into the stomach – was not seriously suggested until 1837, and as far as I can ascertain, not attempted until 1845. Early attempts were apparently 'associated with many complications' (we can use our imaginations I think) so naso-gastric feeding remained the way to go for a while yet.
Now around about 1910, two things were notably happening at roughly the same time. A man called Einhorn was experimenting with nasally-inserted feeding tubes going all the way into the jejunem (what we would call now an NJ tube), that is, all the way past the stomach and into a part of the upper intestines. Elsewhere, research was going on with feeding dogs and trying to maintain a nitrogen balance (essential for healthy survival) by using solutions of hydrolysates. They did not experiment on humans as at this time hydrolysates were thought to be at least indigestible and possibly poisonous to humans. This research led in turn to better understandings in using predigested proteins and the role and use of amino acids, which would in turn help pave the way for modern synthetic enteral formulas. In the 1930s some doctors were starting to pioneer the use of hydrolysate-based formulas (now for humans) in NJ feeding for those whose stomachs were compromised in one way or another. These mixtures used things like a casein hydrolysate; essentially skim milk treated and fortified with acid, pepsin, salt, bicarb soda, dextrose and various vitamins. Even today this is a recognizable outline of the ingredients on the side of some cans of commercial formula.
One of the big issues with percutaneous gastrostomies – sticking a tube through the skin – was the problem of infection. Until the 1940s there were no really effective antibiotics so there was a bit of a disincentive to do a gastrostomy when an NG tube, although a slightly horrible experience for the patient, could do the job. But with the advent of modern antibiotics came an explosion in the sorts of surgeries that would be attempted, and would eventually become commonplace. At around this time too, some doctors began thinking that those experiments with more broken-down formulas for jejunal feeding might be applicable to gastric feeding scenarios as well … and now we can see the modern age rushing in upon us. Interestingly, much of the push to develop very broken-down formulas came about in attempts to meet the needs of patients whose GI systems had nearly or totally shut down – the idea was to feed them more than just glucose intravenously – so the early 20th century also saw the start of the development of central-line IV feeding (where the patient is fed not into the GI tract but directly, intravenously into the blood stream), called Parenteral Feeding.
Fairly quickly, these broken-down, synthesized formulas for enteral feeding became the norm; for a short while at least. It was quite an exciting time for the pioneers, who even went so far as to experiment with feeding patients into the jejunem during surgery. In 1949 polyethylene tubing was first used, and the first enteral feeding pump was developed. But problems of patient tolerance of these broken-down feeds seemed to be commonly arising. In an effort to address this, a sort of return to first principles took place: Hospital kitchens were asked to mimic a normal diet by finely pureeing and liquefying a blend of regular cooked foods, and naturally enough they were generally well-tolerated. The down sides in the hospital environments then though were cost – it was labour-intensive to prepare such foods, and (perhaps ironically) a hospital environment proved a difficult place to keep such foods free of contamination, as compared to sterile synthesized formulas.
In the 1960s, advances in the understanding of the role of amino acids led to further studies designed to see if new formulas could be devised to support patients without the side-effects those early attempts produced. This was supported hugely by the space program, with NASA getting very excited. They could see the great potential in an astronaut 'food' that was concentrated and gave a low fecal residue. These 'elemental diets' had many advantages for the nascent space flight program, in that they stored and transported well, had a very high nutrient density (so were very light), were very soluble so reconstituted easily, maintained an adequate nitrogen balance, and were easily tweaked and adjusted to meet an individual's specific metabolic needs better. But this stuff tasted so bad that the astronauts just refused to eat it. Even today, astronauts eat a largely natural diet, to the extent of taking fresh fruit and tasty baked brownies up with them. Tortillas make awesome edible, low-crumbing zero-gravity frisbees also.
Of course, patients taking their nutrition via tube do not really have a problem with how the solution tastes, and as more and more advances were made in materials for tubes, tube placement surgery and feeding formulas, the formulas derived from the NASA-led research became the standard go-to for tube feeding nutrition. But there was also a sort of medical research arms-race going on, with rapid advances in Parenteral Nutrition. For a while TPN (Total Parenteral Nutrition) was the one attracting all the attention, but quietly research continued in the roles of amino acids and other food constituents, in understanding digestion, absorption and gut physiology. Advances in the development of enteral feeding formulations, tube technology, and the demonstrated lower incidence of complications, lower cost and ease of access eventually moved enteral feeding to the forefront, where it remains the first choice option today.
Something else was going on in the 60's and 70's that related to tube feeding also – far fewer people were dying. Partly this was the result of a slow cultural change that had been gathering pace over the century – we seemed to become a lot less comfortable with allowing death to happen if it was at all avoidable, regardless of circumstances, in much of Western civilization – but a very large factor was technological. The miracles of antibiotics, amazing new drugs, advanced diagnostic and surgical techniques all combined to allow us to save lives that we never before would have been able to save. Serious accidents and injuries that once killed routinely no longer do. Life-limiting illnesses are still on the rise but with advances in treatment and diagnostics patients are tending to live longer. This modern phenomenon is especially pronounced at either end of the age spectrum, with the very young – the very prematurely born even – and the much older citizen.
Of course, saving all these lives means many more people living with serious impairments, a very common such impairment being the inability to eat. Since the last few decades of the 20th century, we've seen an explosion in the number of feeding tubes placed right across the world, most pronounced in countries like the USA. Actual numbers are hard to come by. According to an article published in 2005, there were around 344,000 people using a feeding tube at home in the USA, and the article quoted a 1995 study suggesting that 120,000 patients in long-term care were using feeding tubes also. One thing we do know is that tube placements have continued to grow faster than the population, so it would be reasonable to think there might be half a million to a million people using feeding tubes in the USA alone right now.
To go along with the boom in numbers of tube-fed patients, we now have commercially available enteral formulas in hundreds of different variations; many are very similar, just made by different manufacturers and to different calorie densities, but there are others designed with specific diseases and patient needs in mind. Most recently though, there has been an increasing uptake, driven in the main by parents and carers of tube-fed children and by adult patients themselves, in returning to a more natural food-based diet, often referred to as a blenderized, blended, or pureed-for-gastrostomy diet. It's almost as if we are somehow coming full circle.