Some People Never Eat. Here’s How They Survive.

Food. We need it to live, to survive, to thrive. It’s imperative for everyone that we eat regularly, to ensure enough energy, vitamins, minerals and hydration for our cells.

However, for some individuals, food is not an option. These individuals cannot have a single bite of food or sip of water pass their lips, lest they have horrendous and debilitating symptoms which can leave them unwell for days. These individuals rely on Parenteral Nutrition to survive.

What is Parenteral Nutrition?

Parenteral Nutrition, or PN, is a way of providing key nutrients to individuals who cannot eat or drink anything. It is often the last resort, and only given to individuals who absolutely cannot tolerate anything entering their gastrointestinal tract.

It can be used long- or short-term, depending on the illness and how long the illness will last for.

Short term PN is typically used for those individuals who have had a sudden onset inability to tolerate food, for example, those with a bowel obstruction, or ileus (from a mechanical blockage, such as a tumour or stricture which is due to be removed, or an paralytic ileus, where the bowel becomes paralysed suddenly, which can be due to an operation or numerous other causes). Short term PN is generally given via a Peripheral Venous Catheter in the arm, which is less invasive than a Central Venous Catheter or Central Line.
Long term PN is usually used for those individuals who are likely to not recover any time soon from the illness they have. Those with gastroparesis (paralysed stomach), complicated Inflammatory Bowel Disease (usually due to malabsorption of nutrients, fistulas (where the bowel tunnels to another part of the body) and/or blockages caused by strictures), severe reductions in absorptive capacity (caused by significant bowel resections, trauma, or malabsorption syndromes) and more, these individuals cannot tolerate food or drink in any meaningful amount, nor can they tolerate enteral nutrition (liquid nutrition given via a tube). Their PN is often given via a Central line, a more permanent and less damaging line than a Peripheral line.

PN is the last resort for any person who cannot tolerate food or fluid, and is often only given once all other possibilities have been exhausted.

The Reasons PN is a Last Resort

There are many reasons why PN is not given unless absolutely necessary.

Your risk for sepsis (blood infection) sky rockets. Essentially, you have a direct entryway to your blood stream which has to be handled numerous times per day, and must be kept as sterile as possible to prevent infection. If someone is on PN for life, they have numerous chances every day to contract an infection, which can be fatal.
Your risk for liver disease and liver damage significantly increases. We are not meant to be able to feed ourselves through our veins, and as such, our body isn’t designed to be able to handle that. The fats which have to be given to make PN nutritionally complete (providing omega-3’s and fat soluble vitamins) goes straight into the bloodstream once administered in higher doses than when we eat, and so can lead to the liver becoming overwhelmed and developing fatty liver, which can progress to liver disease.
Damage to veins can occur, and this can limit access at other points in time. For some people on PN, their access becomes so limited and eventually they are unable to get venous access at all; if this occurs, they cannot get nutrition or fluids, nor can their condition be monitored.
Nutrient deficiencies and complications can occur. You’d probably think if something is formulated to ensure it is nutritious, we’d be able to get the right balance of all vitamins and minerals. Unfortunately, that isn’t the case! Osteoporosis and other nutritional deficiencies are common as we cannot get ample amounts of certain nutrients straight into the bloodstream, lest we cause a severe imbalance in electrolytes.
Hyperglycaemia is common; as is to be expected when you put glucose straight into the veins. This can have its own complications.
Not feeding into the gut can cause atrophy, meaning if you can tolerate food going into the GI tract, it needs to be used or you’ll eventually struggle to use it at all.

Essentially, it’s really risky to feed straight into a vein. We don’t do it unless its absolutely necessary; if there is an option for oral intake, or supplemented enteral (tube feeding) intake, we will always choose that.

Parenteral nutrition is complex, and can carry significant risks; however, it can be a lifeline for thousands of individuals who cannot tolerate oral intake. Any questions about PN? Leave them below!