RESEARCH PROJECT: ICU

Jo-Ann Vosloo

Department Critical Care

SBAH

TITLE

Accuracy of serum-myoglobin and serum-creatine kinase in comparison to urinary –

NGAL for the prediction of acute kidney injury in patients with extensive soft tissue injury

NGAL Neutrophil gelatinase associated lipocalin

HUMAN NGAL

: Originally identified as a 25kDa protein covalently bound to gelatinase from neutrophils.

: Synonym = Lipocalin -2, Siderocalin.

: Protease resistant polypeptide

: Released from the distal tubules, secreted with urine

: Responsible for growth and differentiation of renal tubular epithelial cells

: Exerts bacteriostatic effects in the distal urogenital tract by interference with bacterial siderophore - mediated iron acquisition.

: Siderophore-iron-NGAL complex limits proximal tubular damage and reduces apoptosis

: Normally expressed at very low levels in several human tissues: kidney, lungs, stomach, colon.

NGAL

HOWEVER:

Kidney epithelia express and secrete massive quantities of NGAL within 30 minutes in

the urine when damaged by ischemia-reperfusion injury, nephrotoxins, sepsis and

chronic progressive changes.

(Initially demonstrated in pigs, mice and rats. It was confirmed in adults, children and neonates.)

With established AKI it displayed a > 100 fold increase in u-NGAL concentration when compared to healthy individuals.

Kidney biopsies in these patients showed intense accumulation of immunoreactive NGAL in 50% of the cortical tubules. These findings were confirmed with several prospective studies of adults and children who developed AKI.

• Dr M. Haase, Dept. Nephrology and ICU,

University Medicine, Berlin, Germany.

NGAL

NGAL appears to be an early biomarker indicating structural damage to the kidney in contrast to all other markers of renal function available in current clinical practice. Limitations: Age, method of measurement, UTI and co-morbidities associated with non-renal release are modifiers of the predictive performance of NGAL. Need further investigation in large multicenter studies.

• Bennett et al. Clin Jam Soc Nephrol , 2008; 3: 665-73.

DIAGNOSTIC DILEMMA

• S-Creatinine: Is a sensitive marker of AKI, but will only start rising after 1-2 days when the kidney was already exposed to damaging factors and salvage therapy will be too late.

• S-CK (creatine kinase): A level > 5000 U/l is strongly associated with AKI, but it only starts rising 12 hours after rhabdomiolysis. It does not cause renal tubule damage per se.

• S-myoglobin:

The component of rhabdomyolysis that will cause damage to the kidney.

Sharp increase 3-4 hours after rhabdomiolysis, but is not a marker of kidney injury.

The absence thereof does not necessarily predict the absence of AKI.

• AKI:

Refers to a rapidly progressive, yet potentially reversible deterioration of kidney

function.

THERAPIES THAT CAN BE IMPLEMENTED EARLIER

• Intervene timely in relevant hypotension and hypovolemia

optimize hemodynamics

• Avoid nephrotoxic medication e.g. antibiotics, CT-scan with contrast

• Commence RRT earlier

• Optimize non-invasive monitoring

• Earlier double blockade of RAAS (renin angiotensin aldosterone system)

AIM AND OBJECTIVES

1. To determine the accuracy of the standardized urine-NGAL immune assay as predictive biomarker of AKI in trauma and other patients with rhabdomiolysis in the ICU and HCU setting.

2. To determine the accuracy of s-mioglobin and s-CK to predict the development of AKI in patients with rhabdomiolysis admitted to ICU and HCU.

3. To compare the accuracy of these three methods.

• STUDY DESIGN:

Diagnostic study

• SETTING: Surgical and trauma ICU, SBAH

Multidisciplinary HCU, SBAH

Multidisciplinary ICU and HCU, Kalafong Hospital.

INCLUSION/EXCLUSION CRITERIA

• Inclusion criteria:

All the trauma patients admitted to ICU and HCU in SBAH and Kalafong Hospital

• Exclusion criteria:

Patients with a GFR < 60ml/h

Patients younger than 18 years

AREAS WHERE BIAS CAN OCCUR

• Spectrum bias:

= All the patients with higher than normal s-mioglobin and s-CK and not only the cases with grossly deranged values, should be included in the study.

= Patients with hypovolemic shock who has not necessarily been exposed to the damaging effect of the myoglobin molecule, or patients who was exposed to the damaging effects of myoglobin molecule during a period of hypovolemic shock, but in whom the myoglobin value has normalized.

• Observer bias:

All patients who are enrolled in the study must be resuscitated according to the standarized endpionts of resuscitation. This must be obtained within a reasonable short period after admission

ENDPOINTS OF RESUCITATION

• MAP(mean arterial pressure) ≥ 65mmHg

• SVV < 10%

• BE ≥ -4

• Lactate < 2mmol/L

• DO2 > 500ml/min

• CI > 2.4ml/min/m2

• Urine output ≥ 0.5ml/kg/h

• ScVO2 : 70%

Resuscitation will be done according to ATLS standards

Mannitol and bicarbonate treatment must be initiated where it is indicated and according to

existing regimens.

Electrolyte abnormalities must be corrected according to known standard regimens.

Monitoring will be done according to the standards of the Unit.

ENDPOINT OF RESEARCH STUDY Acute kidney injury according to the RIFLE criteria←

Number allocated to Patient: Estimated body mass:

Age: Chronic medication:

Gender:

Co-morbid Conditions:

Ventilation: Yes No

DAY 0 1 2 3 4 5 6

MAP X X X X X X X

CO X X X X

DO2 X X X X

SVO2 X X X X

LACTATE X X X X X X X

SVV X X X X

Urine output ml/Kg/L

average/variation X X X X X X X

BE X X X X X X X

Hb(Het) X X X X X X X

Urea X X X X X X X

Creatinine X X X X X X X

GFR X X X X

NGAL X

Cystatin C X

S-myoglobin X X X X

S-CK X X X X

Bilirubin (T) X

Bilirubin (Cor) X

AST X

ALT X

pH X X X X X X X

PCO2 X X X X X X X

Sats X X X X X X X

PO2 X X X X X X X

HCO3- X X X X X X X

7.) Sc VO2: 70%

4.) Lactate < 2mmol/L

Medical/Surgical

History:

5.) SVV < 10%

6.) Urine output > 0.5ml/Kg/h

PATIENT INFORMATION SHEET

DOCTOR'S INFORMATION

1.) MAP > 65 mm Hg (If known HT, DM or Patient older than 70 years > 70 mm HG)

2.) DO2 > 500ml/mm (Hb, CO, Stats) = relevant (optimize)

3.) BE > -4

PATIENT LIST

Hospital: ________________________________________

Number Allocated Patient Stickers

1

2

3

4

5

• • Confidentiality: • All information obtained from you will be kept confidential. The urinary-NGAL and

Cystatin C test result will be recorded in a professional manner and all information will be kept confidential. A new number will be assigned to your case once the data has been collected preventing a breach in confidentiality.

• • Informed Consent: • I hereby confirm that I have been informed by the doctor about the nature of the

research. I have also received, read and understood the above written information (patient leaflet and informed consent) regarding the study.

• • I am aware that the results of my urinary-NGAL and Cystatin C test, personal details such

as age, sex and hospital numbers will be kept confidential by the investigator. I have had sufficient opportunity to ask all the relevant questions and of my own free will declare myself prepared to participate in the study.

• • • • Patient’s name……………………………………… • • • Patient’s signature…………………………………. Date:

………………………………………... • • I, Dr. ……………………………………………….. (Critical Care Fellow/Registrar) herewith confirm that

the above patient has been informed fully about the nature, conduct, and management of the above mentioned study.

• • • • Investigator’s name……………………….………. • • • Investigator’s signature……………………………. Date:

………………………………………... • • • Witness’s name……………………………………. • • • Witness’s signature……………………………….. Date: ……………………………………… • • • • •

Trial tile: Accuracy of s-myoglobin and s-CK in comparison to urinary NGAL for the

prediction of acute kidney injury in patients with extensive muscle injury. Introduction: You are invited to volunteer for a research study. This leaflet is designed to provide you with information regarding this research project. Before you agree to participate we would like to explain the study to you. If you have not understood everything about the research you are free to ask your surgical doctor and he/she will be more than willing to answer all your concerns. You should not agree to participate unless you understand and are happy to participate. Aims: A very high percentage of patients who are admitted to ICU will develop renal failure. About 30% of these failures can be contributed to extensive muscle breakdown due to different reasons. The muscle breakdown products can damage the kidney. If the healthcare worker can identify injury to the kidney at a very early stage, more aggressive treatment can be started at an earlier stage and thereby prevent renal failure. This will improve the prognosis of the patient and will also lead to a shorter stay in ICU. At this stage there is no definite research on this specific problem. The urinary-NGAL and Cystatin C test will be done routinely on patients who are at risk. The test will be done on urine that was excreted by the patient and it will do no harm to patient. The treatment will be optimal as prescribed by international standards at this stage and no deviation from the excepted gold standard will be applied during conduction of this study. If you agree to participate we ask you to sign this form. The Department of Critical Care at Steve Biko Academic Hospital will perform this investigation on the urine and treat the patient according to accepted international standards.

This research study protocol was submitted to the Faculty of Health Sciences Research Ethics Committee, University of Pretoria and written approval has been granted by that Committee. The study has been structured in accordance with declaration of Helsinki (last updated in October 2000), which deals with recommendations guiding doctors in biomedical research involving human/subjects. A copy is in my possession should wish to view it.

Your participation in this study is absolutely voluntary and refusal to consent for urinary-NGAL and Cystatin C testing does not affect the management of the patient.

Patient/Participant’s formation leaflet and informed consent

Ethical Approval:

Participant Rights:

DATA ANALYSIS

• ROC will be used

and

• Comparison of the area under the curve (AUC) adjusting for the demographic measurements of the subjects ??

• Specificities and sensitivities of s-myoglobin and s-CK will be assessed using NGAL as the reference.

• STATA 12 will be the package of choice

SAMPLE SIZE

• 150 Patients

COST

• Abbott Laboratories will supply reagent for 150 samples for free.

• Lancet laboratories in Jhb will do 150 tests for free.

• Transport of samples from Pretoria to Johannesburg:

R580-00 for 10L box filled with dry ice sample will be delivered the next

day (TNT)

(Lancet Laboratories might be able to help in this regard)

• Abbott Laboratories wants to include U-Cystatin C not included in protocol, statistitian did not review.