High output and your kidneys: the green, amber, red plan

High output has a number attached, and it is worth knowing: more than 1.5 litres in 24 hours. The guidance this comes from was written with Shelagh Bickerton, Lead Clinical Nurse Specialist for Acute Kidney Injury.

The reason it matters is just as plain. Having an ileostomy or internal pouch is a risk factor for acute kidney injury, because high, watery output raises the risk of dehydration and low blood pressure. Studies show 30% of all people with ileostomies will experience high output at some point, with 20% being admitted to hospital due to AKI.

What causes it

• a newly formed stoma or pouch — high output is not uncommon as the remaining bowel adjusts
• bowel affected by disease or treatment: gastroenteritis, food intolerance, IBD, chemo or immunotherapy, antibiotics
• partial bowel obstruction
• not sticking to diet or medication such as loperamide
• excess intake of low concentration fluids such as water

The four steps

1. Prevent high output: adherence to a low fibre diet, loperamide to manage consistency, and 6–8 cups of suitable fluid per day.
2. Know your other risk factors: heart failure, diabetes, chronic kidney disease, liver failure, increasing age, kidney-sensitive medications, previous AKI. The more you have, the earlier you should seek help.
3. Follow the Medicine Sick Day Guidance — pause certain medicines temporarily during any illness that could cause dehydration.
4. Assess your symptoms against the green, amber and red chart, and act on the one you match.

Green

You feel well, you can eat and drink normally, you are not excessively thirsty, you are passing normal volumes, your urine is straw-coloured and you have not lost weight. The actions: low fibre diet, do not eat and drink at the same time, adjust loperamide to output, restrict oral fluids to 1.5 litres per 24 hours — avoiding caffeine, fruit juice and alcohol — of which one litre should be an oral rehydration solution. Weigh yourself daily, and contact your stoma nurse if you are worried.

Amber adds reduced and more concentrated urine, thirst, dry mouth and skin, and slight weight loss — follow everything in green, and contact your stoma nurse or healthcare professional, who may check your bloods to assess kidney function. Attend the Emergency Department if you do not improve.

Red

Dizziness on standing, blood pressure dropping on standing, muscle cramps, spasms and weakness, nausea or vomiting, severe abdominal pain, drowsiness or confusion, new fluid gathering around the ankles or calves, new breathlessness, a fast heartbeat or palpitations, rapid weight loss. Any one of these and the instruction is to suspend medications as per the sick day rules and attend the Emergency Department — taking all your stoma equipment, medications, clothes and toiletries, because you are likely to be admitted.

Why kidneys, of all things

It helps to know what the organs actually do, which makes the rest land harder. Kidneys filter blood of toxins and waste, manage blood pressure, balance fluid and hydration levels, control salts such as potassium, sodium and magnesium, and help make the red blood cells that carry oxygen around the body. Healthy kidneys produce around two litres of urine a day.

To do all that they need adequate blood pressure and blood volume — which is precisely what sustained high output takes away.