Role of Biomarkers in Predicting Contrast-induced Acute Kidney Injury in Critically Ill Patients

Rationale of the study supported by cited literature:

Role of biomarkers in AKI has been established in different clinical settings, to not only early diagnosis but also make prognosis. There are some studies in contrast-induced AKI, mainly in patients undergoing cardiac catheterization. Due to scarcity of prospective studies on this clinically important issue in critically ill patients, there is a need for this proposed study. The investigators will do study to analyse the role of plasma and urinary biomarkers (Neutrophil Gelatinase-Associated Lipocalin (NGAL), Cystatin C and Kidney Injury Molecule-1) in predicting CI-AKI in critically ill patients

The relevance and expected outcome of the proposed study:

With this study, the investigators will be able to know that is there any predictive value of these biomarkers to predict CI-AKI in critically ill patients.

Preliminary work done so far:

No systematic study so far in critically ill medical-surgical ICU patients.

Definition of Contrast-induced acute kidney injury:

Contrast-induced acute kidney injury (CI-AKI) is defined as a rise in serum creatinine of ≥ 0.3 mg/dl from the baseline (before contrast exposure) value within 48 hours after administration of the radiographic contrast

Work plan methodology:

This is a prospective observational study to know role of biomarkers in CI-AKI in critically ill patients. Patients will be included from 2 intensive care units (ICU): 1. ICU of Department of Critical Care Medicine, and; 2. ICU of Department of Neurosurgery. All adult critically ill patients will be consider for inclusion in this study, who will require a contrast-enhanced CT scan of any organ system as decided by the treating clinician and also met study criteria as predefined. After getting written informed consent from the patient or close relatives to participate in this study, patients will be included in this study. There will be no intervention in this study. Treatment of patient will continue as per treating clinician. Transportation of patient for CT scanning will be accompanied by a senior resident and a staff nurse; and relevant monitoring of vitals will be done as per ICU protocol.

Sample collection: Sample will be collected after informed written consent. At baseline, before contrast exposure, 5 ml blood and 5 ml urine will be collected. Similar amount of each will be collected after 04 h, 24 h and 48 h of contrast exposure. Collected samples (plasma and urine) will be stored at temperature of -80 degree centigrade in deep freezer till analysis.

Data collection: Demographic and clinical characteristics of all ICU patients who fulfil inclusion criteria will be collected along with relevant laboratory tests done for patient management. ICU prognostication scores, i.e., Acute Physiologic and Chronic Health Evaluation (APACHE) II score and Sequential Organ Dysfunction Assessment (SOFA) score will also be recorded. Contrast type and volume will be noted. Fluid balance in last 24 hours, uses of nephrotoxic drugs will also be noted.

Intervention: None. Outcome: The primary outcome measure will be development of contrast-induced acute kidney injury (CI-AKI), defined as a rise in plasma creatinine of ≥ 0.3 mg/dl from the baseline (before contrast exposure) value within 48 hours after administration of the radiographic contrast.

Laboratory methods: Samples will be analysed for plasma and urinary creatinine and studied biomarkers before contrast exposure as well as after 04 h, 24 h and 48 h of contrast exposure. Biomarker, Neutrophil Gelatinase-Associated Lipocalin (NGAL), Cystatin C and Kidney Injury Molecule-1 (KIM 1) in plasma and urine, will be analysed by commercially available ELISA kits (RnD) as per manufacturer instructions. Urinary biomarker will be normalized as per urine creatinine values for each sample.