Acute Kidney Injury in the intensive care unit: Risk factors and Outcomes

Shalom, Solomon Patole (2011) Acute Kidney Injury in the intensive care unit: Risk factors and Outcomes. Masters thesis, Christian Medical College, Vellore.


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INTRODUCTION : Acute Renal Failure (ARF) has traditionally been defined as the abrupt loss of kidney function that results in the retention of urea and other nitrogenous waste products and in the dysregulation of extra cellular volume and electrolytes. The loss of kidney function is most easily detected by measurement of the serum creatinine which is used to estimate the glomerular filtration rate (GFR). ARF can be asymptomatic or present with features of azotemia and oliguria or anuria and is diagnosed when biochemical monitoring of hospitalized patients reveals a new increase in blood urea and serum creatinine concentrations. ARF, as opposed to chronic renal failure is often considered to be reversible, although a return to baseline serum creatinine concentrations post injury might not be sufficiently sensitive to detect clinically significant irreversible damage that may ultimately contribute to chronic kidney disease. Its incidence in the ICU in various studies is shown to be around two thirds of number of admitted patients (which makes it comparable to the incidence of acute lung injury (ALI) and severe sepsis), while 4–5% of ICU patients will require some form of renal replacement therapy (RRT). The incidence of ARF is increasing with a higher mortality in those who have more severe renal dysfunction. Even patients who have received dialysis have a mortality of 40-50%. This study was done to evaluate the risk factors for ARF in a developing country as most published studies done so far have been done from developed countries. AIMS OF THE STUDY : To study Acute Kidney Injury (AKI) in a tertiary care Medical Intensive Care Unit in order to document the incidence, evaluate the risk factors for its development and study the outcomes in an Indian setting. PATIENTS AND METHODS : Inclusion Criteria: All critically ill patients admitted in Medical Intensive Care Unit of the hospital. Exclusion criteria: Nil. Sample size: Since most of the data is from Western ICUs and as the patient profile is different from those in India, these numbers could not be used. The incidence of dialyzed patients in the Medical ICU was used to calculate the sample size, as that number would give an estimate of incidence with definite failure (F according to the RIFLE criteria) getting admitted. An estimate of the number of patients with the F class of AKI were identified in the patients admitted in ICU using the dialysis database. The number was 33 out of a total of 132 patients admitted to ICU (25%). Thus substituting p as 25% and q as 75% using the formula: √p x q ⁄ n Where p was sample proportion (25), q was (100-p= 75) and n was 132. A standard error of 3.87 was obtained. A precision of 8% was obtained from this value with a Z of 1.96 being set and with a confidence interval of 95% to estimate an alpha error of 0.05 using the formula: n = z² x p x q / precision² where z=1.96, P=25, Q =75, and precision was 8%,a sample size of 113 was obtained. It was also intended to study 10 variables likely to be risk factors (age, gender, hypotension, primary diagnosis, co morbidities, APACHE II and MODS scoring systems, liver diseases, nephrotoxic drugs, radiocontrast exposure, duration of mechanical ventilation.) and using the rule of thumb of 10 patients for each risk factor, a figure of 100 was obtained which was about the same as obtained by the above formula. RESULTS : A total of 146 patients were included in the study from September 2009 to January 2010. The total number of patients admitted to the Medical ICU during the same period was 146 out of which 114 patients developed AKI which gave an overall incidence of AKI at 78.1%. LIMITATIONS : 1. There were no patients who could be classified under the Loss (L) category in the RIFLE spectrum. 2. There were limited numbers of patients in some of the subgroups to do a statistical analysis. CONCLUSIONS : In this cohort of patients admitted to the Medical ICU 1. A higher risk of developing AKI is found with advancing age, male gender, a higher APACHE II score at admission , hypoalbuminemia, bacterial infections, diabetes and hypotension. 2. The MODS score, liver diseases, tropical infections, the drugs used in the ICU, radiocontrast and other co morbidities were not associated with AKI. 3. A high RIFLE score is associated with a higher need for dialysis and a poorer outcome.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Acute kidney injury ; intensive care unit ; risk factors and outcomes.
Subjects: MEDICAL > General Medicine
Depositing User: Subramani R
Date Deposited: 16 Feb 2018 03:14
Last Modified: 16 Feb 2018 03:14

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