Renal success ​

Acute kidney injury (AKI) – or acute renal failure, as it used to be known – is a major problem among hospitalised patients. If there are delays in detection and it is left untreated, it can lead to serious problems such as uraemia, acidosis or hyperkalaemia, and ultimately death. Despite a national focus on this area in recent years, there remains a feeling that major improvements could be made in patient outcomes while also realising significant cost savings.

There are a number of potential causes of AKI, including dehydration, low blood pressure, some drugs, severe infections, urinary tract blockages, and the dye used for some types of scan. Symptoms can include passing less urine, nausea and sickness, poor appetite, swelling and breathlessness.

Strategies to reduce the incidence of AKI are well known, involving identifying key risk factors, observation and monitoring blood for levels of creatinine, and taking rapid action once AKI is suspected.

Despite many of the preventative steps being part of core healthcare, it is more prevalent than many people would think. 

A study by the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) in 2009 suggested that prevalence among hospitalised patients in the US was 4.9% (although there were no comparable figures at the time for the UK). 

Definition issue

However, there are various definitions of AKI and this has contributed to different estimates of prevalence (see box). Crucially, the NCEPOD study indicated that 30% of AKI cases could be preventable. 

South Tees Hospitals NHS Foundation Trust participated in the original NCEPOD study. Despite this, a care audit in 2012 indicated that little had improved, so more recently it set about addressing the issue, with a particular focus on surgical patients.

Why surgery? Ruth James, director of quality and performance at the trust, explains that AKI was not traditionally seen as a surgical problem – unlike deep vein thrombosis, say, where DVT prevention was embedded in surgical team culture. ‘There was simply less awareness of AKI and the steps that should be taken to reduce risk and to ensure early detection,’ she says.

As recommended nationally, the trust operated an AKI alerting system – flagging up potential AKI indicative test results to consultants. But it recognised that it needed to embed this better into current practice and to develop and sustain an ‘AKI aware’ culture.

Its aim was to accurately measure its AKI rates and then reduce incidence by at least 20% within 12 months – an ambitious target but within the potential improvement identified by the NCEPOD report.

The trust commissioned CRAB Clinical Informatics (C-Ci) to measure morbidity and mortality rates using clinical coded data. This involved extracting patient episodes involving relevant ICD-10 codes as either primary or secondary diagnoses. 

Mark Ratnarajah, a paediatrician and managing director of CRAB, says the company was already involved in supporting work around clinical risk prediction for the trust and was pulled in to support the AKI work. ‘We were asked to get involved because we can do the baselining in real time, and because we were already using coded data,’ he says.

Another possibility would have been to look at pathology results. However, given that some definitions of AKI involve comparing blood creatinine levels with a patient-specific normal level, a single result would not have been sufficient to indicate AKI. In fact, an AKI diagnosis is made by a clinician informed by pathology results as just one part of the evidence. 

While the presence of an ICD code may mean some very minor or early detected cases of AKI – where no code was assigned – are missed, this was seen as a more robust approach in identifying the real incidence. 

The C-Ci system enabled the trust to track the incidence of AKI in surgical patients over the 12 months to June 2016. This was shown to have been rising to a maximum of 1.7% of admissions by June 2016. With access to the national dataset, the company confirmed that this was within the national range for surgical cases of 1% to 2% (the range for medicine is 3% to 6%). But the trust was convinced it could deliver an improvement on this rate.

In parallel to the data baselining exercise, the trust set up an AKI awareness programme, starting in mid-2015. Its aim was to alert staff from all roles and specialties about avoidable patient harm associated with AKI – although the trust has only monitored the impact within surgical specialties. 

Staff workshops

It delivered more than 50 workshops for small groups of staff. These workshops promoted the proper use of the existing alerting system. Training slides were refined on the basis of results and feedback throughout the programme. Prompt cards were developed and handed out as part of a ‘think kidneys’ campaign. The e-alerts were also linked to newly developed AKI guidelines, so that there was a consistent response to the presence of such an alert.

Guidelines were also developed for nursing staff, recognising they play a major role in AKI prevention and detection. They are key to ensuring patients get the right fluid intake and to monitoring for early signs of fluids getting out of balance, including any reduction in urine output. They also dispense drugs that can impact on AKI care.

The final step for the trust was to appoint an AKI/renal advanced nurse practitioner. The nurse practitioner plays a major role in training but also has a daily presence on high risk wards and liaises with primary care, for example ensuring discharged AKI patients are flagged up to GPs helping to avoid readmissions.

The results have been impressive. While it was targeting a 20% reduction over a full year, five months on from its June 2016 baseline, the data showed a 36% reduction in recorded AKI incidence across its surgical wards. And by March 2017 the trust had seen a reduction from its starting point of 1.7% of all surgical patients to just 0.6%.

Dr Ratnarajah says many trusts have run awareness campaigns around AKI. The difference at South Tees was that it had embedded the approach. ‘You’d typically expect rates to fall and then plateau, but we’ve noticed that long after the awareness campaign formally ended, AKI rates continued to fall. Every month has been the lowest month – that can’t continue for ever but it is impressive.’ 

He puts it down to a change in culture – it is now reinforced with junior doctors outside of formal training and by the presence of the advanced nurse practitioner, with prescribing and discharge rights.

The trust’s patient-level cost team calculated that AKI was costing the trust £1.65m a year at the 1.7% prevalence rate. The fall in incidence of AKI equated to 118 episodes a year. And with the difference in costs for patients with and without AKI calculated to be an average of £4,500 – total savings have been estimated at £500,000. This converts into a 6.8 fold return on investment.

‘Reduced length of stay and avoidance of critical care were the key factors in these savings,’ says Ms James. The trust has used the figures to develop a business case to expand its existing service to the full seven days by appointing a further advanced nurse practitioner.