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.
Tubefeeding - a Brief History
