Perioperative Acute Kidney Injury

British Medical Journal 2010;Jul:341Clinical review王審之

Definition of Acute Kidney Injury (AKI)

• Abrupt decline of renal function causing retention of nitrogenous

waste products

• Potentially reversible

RIFLE criteria

Bellomo R, Ronco C, Kellum JA, Mehta RL, Palevsky P, and the ADQIworkgroup. Acute renal failure—defi nition, outcome measures, animalmodels, fl uid therapy and information, technology needs: the SecondInternational Consensus Conference of the Acute Dialysis Quality Initiative(ADQI) Group. Crit Care 2004; 8: R204–12.

Acute Kidney Injury Network (AKIN)

Impact of AKI

Perioperative AKI increases surgical mortality and morbidity and increases hospital costs.

Evidences

• Retrospective studies: 26.4% versus 2.5%– Abelha FJ, Botelho M, Fernandes V, Barros H. Outcome and quality 5 of

life of patients with acute kidney injury after major surgery. Nefrologia 2009;29:404-14.

• Observational study: 25 times more likely to die– Englberger L, Suri RM, Greason KL, Burkhart HM, Sundt TM 3rd, Daly 7

RC, et al. Deep hypothermic circulatory arrest is not a risk factor for acute kidney injury in thoracic aortic surgery. J Thorac Cardiovasc Surg 2010; epub: 13 Apr

Evidences

• Patients who completely recover after postoperative AKI still have an increased adjusted hazard ratio for death of 1.20 (95% confidence interval 1.10 to 1.31, P<0.001) over the longer term compared with patients without AKI according to a recent cohort study.

– Ann Surg 2009;249:851-8.

Careful preoperative assessment can identify patients at particular risk of AKI and could

allow for additional monitoring and planning

Screen patients before OP

• Impaired clinical status ≧ 6 risk factors, 10% of AKI, hazzard ratio: 42.6

– age ≥56 years– male sex– active congestive cardiac failure– presence of ascites– Hypertension– emergency surgery– intraperitoneal surgery– preoperative creatinine >106 μmol/l (1.19mg/dl)– diabetes mellitus

– Anesthesiology 2009;110:505-15.

Screen patient before OP

• ASA physical status score of IV or V odds ratio for AKI: 3.94 (95% confidence interval 2.07 to 7.51; P<0.001)

• High risk surgery (intraperitoneal, intrathoracic, or suprainguinal vascular) odds ratio for AKI: 3.34 (95% confidence interval 2.02 to 5.53; P<0.001)

• Congestive heart disease odds ratio for AKI: 2.34 (95% confidence interval 1.42 to 3.88; P=0.001)

Revised cardiac risk index

• Revised cardiac risk index score• ≧ 3 For AKI: odds ratio 2.45 • ≧ 3 For major cardiac complication: 9%

– high risk surgery– congestive heart disease– ischaemic heart disease– cerebrovascular disease– insulin dependent diabetes mellitus– Creratinie > 2.0mg/dl

Risk factors for AKI (NICE guideline)for individuals undergoing Surgery

• Emergency surgery– when the patient has sepsis or hypovolaemia

• Intraperitoneal surgery• Patients with known risk factors for AKI

– Chronic kidney disease stage 3≧– DM– Heart failure– Age 65≧– Liver disease– Nephrotoxic drug

Daily practice

• Use the risk assessment to inform a surgical management plan– include the risks of developing AKI in the routine

discussion of risks and benefits of surgery

Perioperative AKI rarely indicates an isolated renal problem but rather a physiologically

unstable patient who may deteriorate further and must not be ignored

The successful prevention and management of AKI involves timely recognition of perhaps

subtle abnormalities, basic clinical assessments and observations, and quick and appropriate reaction to information, including

getting senior and specialist help

Right thing, right time

How to diagnose

Ensure that the patient with a diagnosis of AKI is normovolaemic, has an adequate mean

arterial pressure, and preferably is not exposed to nephrotoxins

How to do

• Minimise exposure to perioperative nephrotoxins– ACEI– NSAID

• NSAIDs are best avoided in hypovolaemia or in patients who have sepsis, even if their serum creatinine concentration is normal. (drug safety advice from MHRA UK)

– Perioperative contrast– Antibiotics

• Aminoglycosides, penicillins, cephalosporins, and fluoroquinolones

How to do

• Intraoperative management and haemodynamic optimisation– The aim is to maintain a systemic arterial perfusion pressure that is

appropriate for the patient (taking into account preoperative blood pressure and surgical requirements for relative hypotension)

– Inotrope only after adequate hydration• Hydration: 500 ml crystalloid or 250 ml colloid, repeated as necessary with careful

monitoring for fluid overload. • Monitoring: capillary refill time <3 seconds, restoration of blood pressure, and fall

in arterial lactate concentration.

Many surgical patients have a history of ventricular dysfunction, and optimisation of

cardiac function may require inotropic support

Evidence

• Optimising intravascular volume and cardiac output may have a positive effect on perioperative renal function.– Optimisation of cardiac output or oxygen delivery resulted in a

decreased risk of perioperative AKI • both in the subgroup in which this was started preoperatively and in the combined

subgroup in which it was started either intraoperatively or in the early postoperative phase.

– Both normal and supranormal target achievement were effective in reducing AKI. • Oxygen delivery index: 500 ml/min/m2,

– Crit Care Med 2009;37:2079-90.

Renal tract obstruction must be excluded radiologically within 24 hours of a diagnosis

of AKI

Bladder extension ??

Thanks for your attention