Clinical update

Acute kidney injury: advice for nurses on detecting AKI and caring for patients

How to identify and treat the spectrum of injury formerly known as acute renal failure
Illustration of a diseased kidney

How to identify and treat the spectrum of injury that used to be known as acute renal failure

Picture: Science Photo Library

Essential information

Acute kidney injury (AKI), formerly known as acute renal failure, encompasses a wide spectrum of injury to the kidneys, not just kidney failure, says the National Institute for Health and Care Excellence (NICE).

AKI is seen in about 18% of all people admitted to hospital, with older adults in particular affected. These people are usually under the care of healthcare professionals practising in specialties other than nephrology, who may not always be familiar with the optimal care for AKI.

Inpatient mortality in AKI varies considerably, depending on a number of factors, but in the UK might be 30% or more.

What’s new

NICE has published guidance on the detection, prevention and treatment of AKI. This emphasises early intervention and stresses the importance of risk assessment and prevention, early recognition and treatment. It includes new guidance on preventing AKI in adults having procedures where iodine-based contrast media is used. 

Signs and symptoms

Symptoms include feeling or being sick, diarrhoea, dehydration, reduced urine output, confusion and drowsiness, according to the NHS.

NICE says AKI may be detected by using one of the following criteria:

  • When there is a rise in serum creatinine of 26 micromol/litre or greater within 48 hours.
  • A 50% or greater rise in serum creatinine known or presumed to have occurred within the past seven days.
  • A fall in urine output to less than 0.5ml/kg/hour for more than six hours in adults and more than eight hours in children and young people.
  • A 25% or greater fall in eGFR (estimated Glomerular Filtration Rate) in children and young people within the past seven days. 

More essential clinical updates

Causes and risk factors

Risk factors in adults include:

  • Chronic kidney disease.
  • Heart failure.
  • Liver disease.
  • Diabetes.
  • History of AKI.
  • Oliguria (very low urine output).
  • Neurological or cognitive impairment or disability that results in limited access to fluids because of reliance on a carer.
  • Hypovolaemia.
  • Use of drugs that can cause or exacerbate kidney injury, including non‑steroidal anti‑inflammatory drugs.
  • Use of iodine-based contrast media in the past week.
  • Symptoms or history of urological obstruction or conditions that may lead to obstruction.
  • Sepsis.
  • Deterioration evident in early warning scores.
  • Being aged 65 or over.

RELATED: Assessing and documenting fluid balance

Expert comment

Nicola Thomas, professor of kidney care, London South Bank University, says:

‘AKI is very common. We still don’t know quite how common, but overall about 20% of people admitted to hospital as an emergency have AKI.

‘Nurses need to be able to recognise who is at risk, which includes older people, those with chronic kidney disease or other long-term conditions, those taking medications that can cause kidney injury and those having procedures that use iodine-based contrast media.

‘A common scenario is an older person who is not well hydrated anyway… then something else happens, such as a fall, which means they stop drinking, and at that point the kidneys really shut down.

‘Nurses need to be really aware of AKI, and thinking and asking about it with colleagues when they are caring for those at risk. In hospital, fluid balance charts are often not completed properly but they are essential for monitoring patients at risk of AKI. 

‘Also there is a need to encourage oral hydration before and after procedures using intravenous iodine-based contrast media in adults at increased risk of contrast-induced AKI.’


How you can help your patient

  • Ensure AKI is considered when an adult, child or young person presents with an illness with no clear acute component and has any of the following: chronic kidney or urological disease, new or significant worsening of urological symptoms, symptoms suggesting complications of AKI or symptoms suggesting a multi-system disease affecting the kidneys 
  • Monitor serum creatinine regularly in all adults, children and young people with or at risk of AKI
  • Perform urine dipstick testing for blood, protein, leucocytes, nitrites and glucose in all patients as soon as AKI is suspected or detected. Document the results and ensure appropriate action is taken when results are abnormal

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