Ak Prevention

How can AKI be prevented?
According to the National Confidential Enquiry into Patient Outcome and Death 2009, up to 30% of cases of acute kidney injury may be preventable and the best 'treatment of AKI is prevention.' [3]This can mainly be done by identifying patients most at risk as early as possible. This would involve constant monitoring of urinary output and serum creatinine levels for the high risk patients. However in general, all hospitalized patients with acute illness should be monitored for any symptoms of AKI. In addition minimising the patient’s exposure to nephrotoxic drugs and iodinated contrast agents reduces risk of diagnosis drastically. [3]
However, as mentioned before, AKI is not just a secondary care problem – primary care
has a crucial role to play, particularly in prevention and early detection. [2]Studies have shown approximately two-thirds of patients who are diagnosed with AKI have already developed it when they are hospitalized. [15]This shows strategies for prevention are crucial, and should mainly focus on primary care. In April 2016, AKI Warning Stage Test Results, an electronic system designed for use in labs to detect rising serum creatinine levels, were sent to primary care. [17]
According to NICE guidelines, if the patient has certain conditions that are high risk of developing AKI, investigations for AKI should be done. [19] These conditions include; Chronic Kidney disease (with GFR lower than 60ml/min), heart failure, liver disease, diabetes, history of AKI, and hypovolemia. Investigations include measuring serum creatinine and comparing with baseline.[19]
In addition, patients who are treated with an ACE inhibitor (ACEi) or angiotensin receptor blocker (ARB) are at increased risk of AKI if they develop an illness associated with hypovolaemia and hypertension.[22] One of the major preventative techniques is to identify such patients and educate them while issuing them with a “Kidney Care Card”.
[13] This small card has detailed instructions for temporary cessation of these particular medications, which could be exacerbating and worsening the AKI symptoms. The mnemonic DAMN can be used to remember these drugs.(diuretics, ACEi/ ARBs, metformin, NSAIDs).[8]
Prevention of AKI should follow the following principles;
Risk Assessment
In terms of simply identifying hospitalized patients who would be most at risk, all patients on admission and during their hospital stay should be assessed regularly. The figure to the left gives an example of a risk assessment tool used in the Southern Health and Social Care Trust. [5] AKI in surgical patients is common. Recognising patients at high risk will allow actions to be taken to reduce incidence of renal injury and promote renal recovery as soon as possible. [5]
Optimisation of fluid balance
Patients at risk should have their fluid volume status carefully monitored including fluid depletion and fluid overload. If fluid depletion is high, and oral intake is low, and the patients is at risk of dehydration, according to NICE guidelines the patient should be prescribed maintenance IV
fluids.[23]
Optimisation of blood pressure
A significant indicator of AKI can be hypotension with a systolic blood pressure (SBP) of under 110 mmHg and a mean arterial pressure (MAP) of under 65 mmHg.[23] A patient in this situation needs urgent treatment with IV fluid challenges and vasopressor agents where appropriate.[19]
Medication review
Temporary cessation of ACE inhibitors and most antihypertensive drugs is usually appropriate in patients with dehydration, hypotension with declining renal function.[24] In patients who continue to be prescribed these medications, alteration of timing of drug prescription to 6 pm will allow adequate time to assess clinical state and review their renal function in case there is a need to temporarily hold these medications.[24]
Across the NHS
Since May 2014, NHS Salford Clinical Commissioning Group (CCG) and Salford Royal NHS Foundation Trust (SRFT) have been working together to prevent acute kidney injury (AKI) and improve kidney care. [12] In December 2014, we formed a new group, SPARC (Salford Partnership for Advancing Renal Care), which brought together all primary and secondary care initiatives to ensure a shared strategy and optimise kidney care across the City. For 2015, three AKI indicators were agreed on:[12]
1. Participation in a "sick day" rules project; providing patients with a checklist which they can ill in at home to keep track of their kidney function, and discontinue taking certain medications when warning signs are identified [12]
2. Correct coding, follow up and medication review for patients discharged after an episode of AKI [12]
3. Introducing primary care AKI "e-alerts". This alert will automatically identify patients with AKI and enhance clinicians’ ability to recognize AKI and instigate early treatment.[12]
How is AKI Managed?
Restore Renal Perfusion
As the majority of cases of AKI occur in association with volume depletion and sepsis, it is essential to restore effective renal perfusion as soon as possible. This will allow early recovery of renal function and help to avoid the development of acute tubular necrosis.[21]
Failure of the patient to maintain an effective blood pressure following this regime should raise the possibility of underlying sepsis or significant ongoing losses. Both these latter scenarios require senior assessment rather than continuing to prescribe increasing large volumes of fluid in the face of poor urine output. [25]
Relieving urological obstruction
Generally, any patient with upper tract urological obstruction should be referred to a urologist. It should be done immediately if one or more of the following is present: pyonephrosis, an obstructed solitary kidney, bilateral upper urinary tract obstruction, and complications of acute kidney injury caused by urological obstruction. [26]
Obstruction causes 5-10% of adult cases of AKI in secondary care.[27] Lower urinary tract obstruction, usually reversible, is relieved by urinary catheterisation. Upper urinary tract obstruction normally occurs with diseases that involve the ureter of the kidney. [27]More invasive treatments are required for upper urinary tract obstructions, such as nephrostomy or stent insertion. Whilst rapid relief of upper tract obstruction in patients with AKI can be critical in preventing complications, there are variations in availability of emergency urology services.[27]
Prescribe Medicines Safely
Patients who develop AKI require revision of all prescribed medications. [28] These include all medications interfering with renal regulation and those medications with the potential to reduce blood pressure. [28] Antihypertensive medications (including diuretics) should be withheld in patients with hypotension. Patients treated with beta blockers need careful consideration of the risks and benefits of temporary cessation.[28]
Pharmacological management
Loop diuretics are not usually offered to treat AKI and are only considered for treating fluid overload or oedema while the patient is awaiting renal replacement therapy, or renal function is recovering in a patient not receiving renal replacement therapy. This in turn, for example, may forestall or aid mechanical ventilation.[26]
The role of loop diuretics in the prevention and treatment of acute kidney injury (AKI) is uncertain.
[31] The table below is a review of five studies and their findings on the clinical uses of loop diuretics and their effects on mortality rates in AKI. All five studies used furosemide, but a variety of doses were used, with maximal daily doses ranging from under 1g to 3.2g.[31] It shows inappropriate use of loop diuretics may exacerbate renal hypoperfusion through vasodilatation and excessive diuresis resulting in worse outcomes. It is therefore essential to assess the role of loop diuretics in treating established
AKI.[31]