Renal protective strategies in the ICU

1. Renal protective strategies in the ICU Kishore P. Critical care conference

2. Why renal protection? Kishore P. Critical care conference

3. RIFLE classification of ARF Crit Care. 2004 Aug;8(4):R204-12

4. Acute renal failure • 67% of ICU admissions • Mortality • R-8.8% • I-11.4%, hazard ratio 1.4 • F-26.3%, hazard ratio 2.7 • Cost • Technology requirements Kishore P. Critical care conference

5. Prevention is better than cure Desiderius Erasmus Kishore P. Critical care conference

6. Causes of ARF in the ICU • Primary disease activity • Shock states • Sepsis syndromes • Infections-malaria, scrub, leptospirosis • Nephrotoxic drugs • Contrast nephropathy • Vascular-anastomotic, athero and cholesterol embolisation Kishore P. Critical care conference

7. Renal protection - general • Ensure adequate renal perfusion • Avoid / minimize use of nephrotoxic drugs including radio contrast • Early recognition and aggressive management of sepsis Kishore P. Critical care conference

8. Adequate renal perfusion Kishore P. Critical care conference

9. Adequate renal perfusion • Blood pressure • Intravascular volume • Cardiac output • Other markers of perfusion Kishore P. Critical care conference

10. Scenarios • 60 year old lady presented with urosepsis to the casualty. She had not passed urine for the last 6 hours. Blood pressure on arrival was 60mmHg systolic. She was catheterized and 50ml of urine was drained. 1 liter of crystalloids is rushed in and dopamine is started-BP picks up to 100/40mmHg. She reaches ICU after 2 hours. The MAP is 64mmHg. She is treated with 1 liter of Haesteril, and output increases to 45ml per hour for the next hour, and gradually trails off. Her creatinine is 1.5, and goes up to 3.2 the next day. Kishore P. Critical care conference

11. A 76 year old female undergoes a sigmoid colectomy for ruptured diverticulum. Her baseline blood pressure is 140/80, MAP 100mmHg. She requires multiple boluses of phenylephrine in the  operating room to support her blood pressure. On return to intensive care, the patient is mechanically ventilated. Her urinary output is 15ml in the first hour. She is treated with 1 litre of colloid, her CVP rises to 14cmH2O, she puts out little urine, and her blood pressure remains 90/50 mmHg (MAP 63). The registrar starts a noradrenaline infusion, targeted at a MAP of >80mmHg, and the patient’s urinary output increases to 70 to 100ml/hour. Over the next 48 hours, each time the vasopressor was weaned and the MAP fell below 75mmHg, so too did the urinary output. Eventually, the patients blood pressure recovers, and she is weaned from ventilation and vasopressors without further difficulty. Kishore P. Critical care conference

12. Renal Autoregulation • Renal Medullary Hypoxia • Tubuloglomerular Feedback Kishore P. Critical care conference

13. CCM tutorials.com

14. CCM tutorials.com

15. Blood pressure • Renal autoregulation suboptimal below 80 and lost below 60mmHg • Renal success Vs renal failure Kishore P. Critical care conference

16. Blood pressure • Target MAP of 70mmHg normally in ICU • 80mmHg in patients with oliguria, established renal failure, longstanding hypertensives and raised ICP Kishore P. Critical care conference

17. Intravascular volume • Target CVP of at least 14-16mmHg • Fill till signs of overfill just manifest • CVP>16mmHg • Drop in P/F ratio • Bilateral crackles • S3 • Loss of stroke volume variation • Fill to targets, do not go by numbers! Kishore P. Critical care conference

18. CO and other markers of perfusion • Cardiac output assessment • Urine output • Base excess and lactate • ScvO2 Kishore P. Critical care conference

19. Sepsis syndromes Kishore P. Critical care conference

20. Renal failure in sepsis • Shock • Cytokine damage • DIC • Drug induced Kishore P. Critical care conference

21. Principles of optimizing renal perfusion • Specific measures • Low dose dopamine • Fenoldopam • Dopexamine • Intensive insulin therapy • Ischemic preconditioning Kishore P. Critical care conference

22. Low dose dopamine • Renal dose-2.5mcg/kg/min-renal vasodilation • Meta-analysis: low-dose dopamine increases urine output but does not prevent renal dysfunction or death. • Can actually worsen renal perfusion • No role. Ann Intern Med. 2005 Apr 5;142(7):510-24 Kidney Int. 2006 May;69(9):1669-74 Kishore P. Critical care conference

23. Fenoldopam • Dopamine-1 receptor agonist • Selective renal vasodilation • Many small trials. Evidence inconclusive • Recent RCT - did not show significant reduction in renal failure with Fenoldopam Crit Care Med. 2005 Nov;33(11):2451-6 Kishore P. Critical care conference

24. Dopexamine • Beta2 and dopamine agonist - inodilator • Not useful British Journal of Anaesthesia 2005 94(4):459-467 Kishore P. Critical care conference

25. Intensive insulin therapy • Intensive insulin therapy in the SICU to maintain capillary sugars between 80-100mg/dl reduced acute renal failure requiring dialysis or hemofiltration by 41 percent • However subsequent study in the MICU did not support this. However new onset rise in creatinine was reduced (12.6 vs 8.3%). No difference in dialysis requirement. N Engl J Med. 2001 Nov 8;345(19):1359-67 N Engl J Med. 2006 Feb 2;354(5):449-61 Kishore P. Critical care conference

27. Nephrotoxic drugs Kishore P. Critical care conference

28. NSAIDs • ACE inhibitors • Aminoglycosides • Last straw • Consider alternatives • Weigh risk vs benefit Kishore P. Critical care conference

29. Contrast • Incidence of contrast nephropathy 2% in non-critically ill patients • Rise in s.creat. By 0.5mg% or a 25% increase from baseline 48-72 hours after contrast exposure • Is contrast really necessary? • Non ionic contrast • Hydration • N-acetyl cysteine • NaHCO3 • Fenoldopam • Ascorbic acid, theophylline Kishore P. Critical care conference

30. Hydration • Most effective stand alone intervention • 1000-2000 ml in the 12 hours prior to the procedure Clin Nephrol. 2004 Jul;62(1):1-7 Kishore P. Critical care conference

31. N-acetyl cysteine • RCTs show inconsistent results • Meta-analyses – show benefit • 2gms over 6 hours Clin Cardiol. 2004 Nov;27(11):607-10 Kishore P. Critical care conference

32. Bicarbonate • Better than saline alone • 3ml/kg/hr 1 hour before procedure followed by 1ml/kg/hr for 6 hrs after JAMA. 2004 May 19;291(19):2328-34 Kishore P. Critical care conference

33. Hemodialysis and filtration in pre-existing renal failure Kishore P. Critical care conference

34. Specific situations • Rhabdomyolysis: 10% mannitol and hydration to maintain urine output 100ml/hr • Cholesterol embolisation- care during cath procedures Kishore P. Critical care conference

35. Oliguria in the ICU • Rule out obstn, abdominal compartment syndrome • BP, volume, CO target optimisation • Diuretics only if all above fulfilled Kishore P. Critical care conference

36. Organ preference • Prefer the lung to the kidneys – do not fill the kidneys and flood the lungs Kishore P. Critical care conference

37. The superior doctor prevents sickness; The mediocre doctor attends to impending sickness; The inferior doctor treats actual sickness; Chinese proverb