Wednesday, November 13, 2013



                                        Dr. AKKINENI LOKESH

                                                           MAY 2013
                                       UNDER THE GUIDANCE OF
                                              DR. CHAITRI SHAH 
                                      ASSOCIATE PROFESSOR
                             DEPARTMENT OF ANAESTHESIOLOGY



AKI is sudden impairment of kidney function resulting in the retention of nitrogenous and other waste products normally cleared by the kidneys.[1] Kidneys maintain water and solute homeostasis, guarding the body’s internal mileu.''[2]  AKI is not a single disease but, rather, a designation for a heterogeneous group of conditions that share common diagnostic features: specifically, an increase in the blood urea nitrogen (BUN) concentration and/or an increase in the plasma or serum creatinine (SCr) concentration, often associated with a reduction in urine volume. Sudden disruption of previously normal or stable kidney function usually occurring over hours or days'' is termed acute renal failure. ARF can occur in setting of antecedent chronic renal insufficiency.[1] Clinically manifested by oliguria, rise in blood urea and creatine, acidosis and electrolyte imbalance.[2] AKI complicates 5–7% of acute care hospital admissions and up to 30% of admissions to the intensive care unit.[1]

 In cardiac surgery, baseline renal function is likely the most important determinant of
postoperative AKI, particularly severe AKI requiring dialysis. Additionally, the cardiovascular status of the patient also influences the postoperative AKI risk. For example, functional status of congestive heart failure, presence of peripheral vascular disease, and preoperative use of intra-aortic balloon pump have all been associated with increased risk of AKI. Other co-morbid conditions such as diabetes, along with the extent of glycemic control are also independently associated with development of AKI after surgery.[3, 4]

Whereas, In non cardiac surgery, risk factors for AKI have been identified. Kheterpal et al[5], studied patients with preoperative normal renal function for non cardiac surgery and developed a preoperative renal-risk index that identified the following independent risk factors for renal failure: age, emergent surgery, liver disease, body mass index, high-risk surgery, peripheral vascular occlusive disease, and chronic obstructive pulmonary disease (requiring chronic bronchodilator therapy). It is well known that ARF can be associated with vascular surgery. Baseline renal function, ischemia time (aortic cross-clamp time), and intraoperative hypotension are key determinants of postoperative AKI in this setting.

We also hypothesized that incidence of post op AKI in the preoperatively normal renal function in Non-cardiac surgery can be identified early by various Pre-operative and Intra operative predictors, to have them in mind will be useful to prevent adverse post operative outcome related to AKI.


·        Incidence of Acute Kidney Injury in post operative non cardiac surgical patients with base line normal renal function.

·        To predict and identify the risk factors with base line normal renal function.

                                 REVIEW OF LITERATURE:

Incidence of Preoperative AKI

     Until recently, the definition of AKI was not standardized. Authors have used terms   such as renal   insufficiency renal dysfunction, acute renal   failure   (ARF),  and   renal   failure   requiring  dialysis  somewhat interchangeably. Parameters used to define these terms include absolute creatinine values, absolute and percentage changes in creatinine values, absolute and percentage changes in estimated glomerular filtration rates (GFR), and reduction in urine output. The term ‘‘acute kidney injury’’ has been recently introduced in 2 different classification systems.


Acute Kidney Injury

Net work Criteria

RIFLE Criteria

Urine Output

Urine Output
Increased Cr.0.3mg/dL
Or Cr 150% baseline
UOP <0.5ml/kh/h
For 6 h
Increased Cr 1.5
Or GFR decreased 25%
UOP < 0.5ml/kg/h
For 6h
Cr 200%-300%
For 12h
Injury (I)
Increased Cr 2
Or GFR decreased 50%
UOP <0.5ml/kg/h
Cr >300% of baseline or 4mg/dl with 0.5mg/dl acute increase
UOP <0.3ml/kg/h
For 24hor
Anuria for12h
Failure (F)
Increased Cr 3 or GFR decreased <75% or Cr>4mg/dl with 0.5mg/dl acute increase
UOP <0.3ml/kg/h
For 24h or
Anuria for 12h

     As seen in Table 1, these definitions include creatinine change, GFR change, and measurements of urine output. The first system was the RIFLE criteria (with worsening function progressing from Risk to Injury to Failure to Loss to End-Stage Renal Failure) of the Acute Dialysis Quality Initiative.[6]

     More  recently, the  Acute  Kidney  Injury Network, a  consensus panel involving  national and  international societies in nephrology and  critical care,  proposed standard definitions of AKI, and  graded the  severity  of  kidney  injury  into 3 stages.[7] These criteria define  AKI as an increase in serum creatinine level by 0.3 mg/dL  (or  1.5 times)  relative  to baseline. Subsequently, the  severity  is divided into  3 stages  based  on  degree  of creatinine elevation (stage  I–1.5  to 2 times  increase; II–  >2 to 3 times increase; and  III–  >3 times increase, new requirement of dialysis, or an absolute    creatinine  value   of   >4 mg/dL   with   at   least    0.5 mg/dL increment). There are   caveats   to  these   criteria,  in  that   they   await broader validation across  all patient care  settings.

   Compared to the RIFLE criteria, the AKIN criteria do not materially improve the sensitivity, robustness and predictive ability of the definition and classification of AKI in the first 24 h after admission to ICU [8].

The rate of perioperative AKI is difficult to know precisely as it is dependent on definitions used and type of surgery studied. In  cardiac surgery, rates of kidney  injury  range between 7.7%  and 11.4%[4,9,10] when defined  broadly, Kheterpal et al[5]    recently studied  a  noncardiac surgery  population  with  pre- operative normal renal  function and  noted an incidence of renal  failure defined by GFR  less than  50 mL/min as 0.8%.  After aortic aneurysm repair, incidences of  renal   failure   of  various   definitions  have   been reported at 15% to 46%[11,12].Expectedly, the incidence of AKI after  cardiac  transplant is generally higher than  non transplant cardiac surgery; in a single  center study  involving  over  750 cardiac  transplants the   incidence  of  AKI  requiring dialysis  was  6%.[13]  On   the   basis  of historical  comparisons, this  observation was about  6-fold  higher than nontransplant cardiac  surgery performed during the  same  time  period at that institution.

Impact of AKI on Mortality: A Case for Preoperative Assessment

Postoperative AKI is one of the most serious complications during hospitalization, increasing morbidity, mortality, length of stay, and costs of care.

  When AKI occurs preoperatively, morbidity and mortality increase. In   cardiac   surgery many   studies   have   reported increased mortality related to  renal   failure  requiring dialysis.  Zanardo et  al[8]   reported  a mortality  rate   of  0.8 in  patients  without renal   dysfunction,  9.5% mortality rate  with renal  dysfunction, and  44.4% in patients with renal failure.  Some have reported mortality as high as 89% when renal failure occurs after cardiac procedures.[4]

     In noncardiac surgery, AKI also substantially worsens outcomes. It is notable  that   in  a  retrospective  study   of  more than   15,000   patients without preexisting renal  dysfunction the  30-day,  60-day,  and  1-year mortality increased from  2.7%  to 15%,  5.1%  to 17%,  and  15%  to 31%, respectively  in   patients  who   developed  ARF. Factors  that  have been  found to adversely affect survival  include the  need for  ionotropic support, ventilation for more than  3 days  or  failure  to wean  from  mechanical ventilation, age greater than  65, vascular  disease  score, need for additional surgery, and the  presence of  systemic  inflammatory response  syndrome or  multi- organ failure.[14,12,15]

  Preoperative Risk Factors

It  can  be hypothesized that  AKI after  a surgical  procedure results from  preoperative comorbid status,  the  type of surgical  procedure, and immediate  postoperative  course.  Regarding  the   preoperative   risk factors  of AKI,  advanced age  is consistently associated  with  increased risk of AKI, regardless of the clinical setting.[5,12,16-19] In cardiac surgery, baseline   renal   function is  likely  the  most  important  determinant  of postoperative AKI, particularly severe  AKI requiring dialysis. Additionally the   cardiovascular status   of   the   patient also   influences the postoperative AKI risk.  For example, functional status  of  congestive heart failure,  presence of peripheral vascular  disease,  and  preoperative use of intra-aortic balloon  pump have all been  associated  with increased risk  of AKI.[3] Other comorbid conditions such  as diabetes, along  with the  extent of glycemic  control are  also  independently associated  with  development  of  AKI  after   surgery.[4]  

    In  noncardiac surgery, different risk factors for AKI have been identified. As previously cited,  Kheterpal et  al[5]   studied patients with preoperative   normal  renal    function  for   noncardiac surgery  and developed a preoperative renal-risk index  that  identified the  following independent risk factors  for  renal  failure:  age,  emergent surgery, liver disease,    body   mass   index,  high-risk  surgery peripheral   vascular, Occlusive disease,  and  chronic obstructive pulmonary disease  (requiring chronic bronchodilator therapy). On the basis of the incremental score, the frequency of renal failure increased ranging between 0.3% and 4.5%.

     It is well known that ARF can  be associated  with  Baseline  renal   function, ischemia  time (aortic cross-clamp time), and  intraoperative hypotension are key determinants of postoperative AKI in this setting.

Intraoperative Risk Factors

Several intraoperative risk factors have been associated with AKI. These factors  are  difficult  to  quantify, unless  they  were  meticulously recorded during the  surgery, and  may  still represent as surrogate for unmeasured events  during the  surgical  procedure.
    In  noncardiac surgery, there  are  fewer  studies   describing intra- operative  risk   factors   that   are   independently  associated   with   AKI. Kheterpal et al[5]     determined if the  intraoperative risk  factors  of use  of a vasopressor  infusion,  mean   number   of   vasopressor   bolus    doses administered, and  the  administration of furosemide or  mannitol were added  to  the   analysis. In  it they  included the intraoperative risk  factors  of units  of packed red  blood  cells required, hypotension defined as mean arterial pressure less than  50 mm Hg, Although the value of each of these  individual risk factors  is unknown, the  absence  of them  is reassuring.
Postoperative Assessment

Several events during the postoperative period can influence renal function. The literature in this regard is more difficult  to interpret due to the  lack of clear  temporality between nonrenal events  and  AKI.
      Postoperative serious events also lead to AKI in noncardiac surgery. In  vascular  surgery, the  overall  need for  ionotropic support and  the need  for   longer   postoperative   mechanical  ventilation  have   been associated   with  AKI.[12,15] 
There is ample  evidence that  postoperative AKI is associated  with other  nonrenal  complications, and   together,  the   number  of  organ failures  contributes to  an  increased mortality risk. Thakar et al[20] (Kidney  International 2003)  examined postoperative AKI  and sepsis/infections. There  was increased risk  of  postoperative  infections with worsening degree of severity of AKI.

Albright RC[21] studied, Acute renal failure (ARF) affects in almost all medical specialties. Its occurrence seems to be increasing in hospitalized patients. A structured approach to the evaluation and management of ARF would facilitate rapid diagnosis and treatment in most patients. Appreciation for the multiple drugs that affect renal function is especially important. Exclusion of urinary outflow obstruction and administration of therapies that improve renal perfusion should be given top priority with respect to managing ARF.

Mangano[4], Christina Mora MD; studied, Acute changes in renal function after elective coronary bypass surgery incompletely characterized and represent a challenging clinical problem determined that patients having elective myocardial revascularization develop postoperative renal dysfunction and failure, which are associated with prolonged intensive care unit and hospital stays, significant increases in mortality, and greater need for specialized long-term care.

Kheterpal et al[5], studied predictors of postoperative acute renal failure after noncardiac surgery in patients with previously normal renal function . Seven independent preoperative predictors were identified : age, emergent surgery, liver disease, body mass index, high-risk surgery, peripheral vascular occlusive disease, and chronic obstructive
pulmonary disease necessitating chronic bronchodilator therapy. Several intraoperative management variables were independent predictors of acute renal failure: total vasopressor dose
administered, use of a vasopressor infusion, and diuretic administration. Acute renal failure was associated with increased 30-day, 60-day, and 1-yr all-cause mortality. Conclusions: Several preoperative predictors previously reported to be associated with acute renal failure after cardiac
surgery were also found to be associated with acute renal failure after non cardiac surgery. The use of vasopressor and diuretics is also associated with acute renal failure.


                                MATERIAL AND METHODOLOGY:

Type of  Study:
Prospective  Observational  Study.

Study Centre:
DHIRAJ  HOSPITAL affliated to SBKS medical Institute and Reasearch Centre

Data Collection:
Patients will be selected according to inclusion and exclusion criteria.
The written informed consent will be obtained from them and they will Undergo a complete clinical history and physical examinations

Following details of the patients included in the study will be obtained 
        Pre-operatively :-
·        Age
·        Sex
·        Diagnosis clinical
·        Co-morbid condition
·        Drug history
·        Past history

Pre Operative Investigations :-
·        Haemogram
·        Urine routine
·        Urine micro
·        R.B.S
·        Serum creatinine
·        Blood Urea
·        Serum electrolytes
·        Urea Nitrogen
·        Estimated GFR- Creatinine clearance using the
Cockcroft-Gault formula-(140-age in years) x(weight in kilograms)
                            (72x serum creatinine in mg/dl]) x (0.85  for females).

·        ECG
·        Echocardiography
·        Other special investigations (If any)

One the day of Surgery following details will be obtained:-
·        Nil By Mouth period  (NBM- No of  Hours)
·        Type of Surgery
·        Pre operative fluid (Amount)
·        Drugs given
Intra operative:-
·        Type of Anesthesia
·        Duration of  surgery
·        Blood loss
·        Hypotension (SBP < 90 mm of Hg)
·        Bolus fluid
·        Vasopressors
·        Diuretics
·        Urine output
Post Operative:-
·        Urine output total on the day for 72 Hrs
·        Renal Function Test – Day 1 to 3
·        Primary outcome
·        Post operative AKI will be defined and classify as per RIFLE CRITERIA
·        Days of hospitalization
·        Hospital Outcome  - Discharged/ Died


All patients undergoing major Non-cardiac surgeries:

·         With Normal serum creatinine levels pre operatively
  Surgeries Include:

·        Spinal Anesthesia
·        Epidural Anesthesia
·        General Anesthesia


All patients undergoing

·        Cardiac surgeries
·        Vascular surgeries
·        Deranged  baseline Kidney function
·        Sepsis
·        Radiological contrast prior 48 hrs


Ø Complete blood count

Ø Renal Function Test

Ø Serum electrolytes

Ø Random blood sugar
Ø Blood Urea Nitrogen

Ø Urine Routine/Microscopy

Ø Random blood sugar


Ø Echocardiography


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2.      Harrison

3.      Thakar CV, Liangos O, Yared JP, et al. ARF after open-heart surgery: Influence of gender and race. Am J Kidney Dis. 2003;41:742–751.

4.      Mangano CM, Diamondstone LS, Ramsay JG, et al. Renal dysfunction after myocardial revascularization: risk factors, adverse outcomes, and hospital resource utilization. The Multicenter Study of Perioperative Ischemia Research Group. Ann Intern Med. 1998;128:194–203.

5.      Kheterpal S, Tremper KK, Englesbe MJ, et al. Predictors of postoperative acute renal failure after noncardiac surgery in patients with previously normal renal function. Anesthesiology. 2007;107:892–902.

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8.      S.M.Bagshaw et al, A comparison of the RIFLE and AKIN criteria for acute kidney injury in critically ill patients Nephrol Dial Transplant (2008) 23: 1569–1574 doi: 10.1093/ndt/gfn009 Advanced Access publication 15 February 2008.

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13.  Boyle JM, Moualla S, Arrigain S, et al. Risks and outcomes of acute kidney injury requiring dialysis after cardiac transplantation. Am J Kidney Dis. 2006;48:787–796.

14.  Berisa F, Beaman M, Adu D, et al. Prognostic factors in acute renal failure following aortic aneurysm surgery. Q J Med. 1990;76:689–698.

15.  Braams R, Vossen V, Lisman BA, et al. Outcome in patients requiring renal replacement therapy after surgery for ruptured and non-ruptured aneurysm of the abdominal aorta. Eur J Vasc Endovasc Surg. 1999;18:323–327.

16.  Chawla SK, Najafi H, Ing TS, et al. Acute renal failure complicating ruptured abdominal aortic aneurysm. Arch Surg. 1975;110:521–526.

17.  Olsen PS, Schroeder T, Perko M, et al. Renal failure after operation for abdominal aortic aneurysm. Ann Vasc Surg. 1990;4:580–583.

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19.  Waikar SS, Liu KD, Chertow GM. Diagnosis, epidemiology and outcomes of acute kidney injury. Clin J Am Soc Nephrol. 2008;3:844–861.

20.  Thakar CV, Yared JP, Worley S, et al. Renal dysfunction and serious infections after open-heart surgery. Kidney Int. 2003;64:239–246.

21.  Robert C. Albright, JR, DO, Acute Renal Failure: A Practical Update, Mayo Clin Proc. Jan. 2001;76:67-74.