Clinical Profile of Acute Kidney Injury in a Tertiary Care Pediatric Intensive Care Unit using KDIGO (Kidney Disease: Improving Global Outcomes) Criteria.

Aims and Objectives The aims & objectives of this study are - In the patients admitted to the Pediatric intensive care unit (PICU) -  1. To determine the frequency of AKI. 2. To stage the AKI according to KDIGO criteria. 3. To study the outcome of AKI. 4. To study the effect of AKI on the length of PICU stay & hospital stay. Materials and Methods

Type of Study The present study will be a single-centre, observational, non-interventional study.

Setting: Level III Tertiary Care Pediatric (Medical) Intensive Care Unit (PICU).

Study site: The study will be conducted in patients admitted to the PICU of KEM Hospital, Mumbai, which is a tertiary care, 14-bedded PICU with state-of-the-art facilities including mechanical ventilators, non-invasive monitors and other devices for delivering critical care. It is manned by at least 4 junior resident medical officers around the clock. One Professor looks after the day-to-day clinical and administrative matters of the PICU and is assisted by one Associate Professor and one Assistant Professor. Fellows (MUHS) and senior registrars are also posted in the PICU (when available).

Study period: The study will be conducted over 18 months (prospectively) after approval from the IEC. The study enrolment will be done for 12 months. Each patient will be in the study till his/ her stay in the PICU.

Sample size calculations: Annually about 400 patients are admitted to the PICU. Of these approximately 300 consecutive patients (admitted to the PICU) will be enrolled. This sample size has been decided as per the number of annual admissions in the PICU (convenience sampling).

Ethics: The study will be initiated after seeking approval from the “Institutional Ethics Committee (IEC)” of the institute/ hospital. The study will be conducted in compliance with the “Ethical Guidelines for Biomedical Research on Human Participants” by the Indian Council of Medical Research (ICMR).

Consent: Case enrolment will be done after written informed consent from the parent/guardian. Assent will be obtained from patients more than 7 years of age. Since patients in the PICU are critically ill, the assent will be procured from children aged 7 years and above once the clinical condition stabilizes and when they are in a position to give the assent. Inclusion criteria: All consecutive patients (aged more than 28 days to up to 12 years of age) requiring PICU admission (with or without a previous ward stay) will be enrolled over 12 months. Readmissions to PICU will be included as separate admissions for this study (since each episode requiring critical care presents new variables potentially affecting the outcome).

Exclusion criteria: The following patients will be excluded from the study -  1. Parent/ Guardian refusing informed consent. 2. Children with pre-existing AKI/ chronic renal disease/ end-stage renal disease. 3. Pre- and post-surgical, trauma, and burns patients (as these patients are not usually admitted to our medical PICU). Confidentiality: The participant’s details will not be disclosed at any point in time. Study Procedure & Data Recording:

All consecutive patients admitted to the PICU within the study period (except those falling in the exclusion criteria) will be included after obtaining valid, informed, written consent from the parent/ guardian. Prospective data will be recorded from indoor case sheets/ papers when the patient is in the PICU.

The following data/information will be recorded in a pre-designed case record form- CRF (from the patient’s hospital case sheets/indoor medical papers)-

Demographic details: name (initials), age (in months), sex, height, weight, date of admission to the hospital and date of admission to the PICU.

Clinical details: The following clinical details will be recorded- 1. Indication for PICU admission,  2. Final complete diagnosis, 3. Primary system involved, significant/diagnostic investigations, complications & treatment,  4. Risk factors for AKI (hypovolemia, shock, sepsis, mechanical ventilation, PICU stay >7 days & use of nephrotoxic drugs), 5. Daily creatinine value (as available) and urine output, and  6. Outcome-related data: Outcome of the patient (survival/ death), length of PICU stay and length of hospital stay will be noted. The patient’s daily medical records will be scrutinized from admission until discharge from the PICU/ death. All investigations done routinely in the PICU as a part of the treatment protocol will be recorded in the CRF. This study will not entail performing any new/ additional investigations or new/ additional treatment or any financial burden to the hospital or financial burden to the parent/ guardian. Serum creatinine & urine output: Serum creatinine estimations are usually done daily during the first week of admission to PICU. The available values will be recorded in the CRF. The creatinine clearance (Cr Cl) will be calculated in mL/min per 1.73 m2 by the Schwartz formula* (please see below). Urine output will be monitored hourly (as the current practice in PICU). Daily estimation of serum creatinine value and frequent estimations of urine output are done in all patients admitted to the PICU as a part of routine monitoring for early diagnosis of end-organ involvement. No additional investigations will be carried out on the patients for this study alone. The amount of blood required for every estimate will be around 0.5 ml.

*Schwartz formula is: Cr Cl = (k * Ht) / (Cr serum); where ht is height in cm & ‘k’ is constant as given in the Table below19-

Age

K value

|Low birth weight during the first year of life

0.33

|Term age in the first year of life

0.45

|Children and adolescent girls

0.55

|Adolescent boys

0.70

Baseline creatinine value will be considered as the value estimated within the past 6 months before admission to PICU or on hospital admission or on PICU admission (whichever is earlier). If none of these are available then it will be considered as 100ml/ min/ 1.73m2.The change in creatinine clearance or urine output within 48 hours or over one week will be considered to diagnose and stage acute kidney injury according to the KDIGO criteria (as given below). Patients will be followed up for a total of one week (at least) even if they are transferred out to the wards to stage the kidney injury. Kidney Disease Improving Global Outcomes criteria (KDIGO)6:

AKI stage

Serum creatinine

Urine output

|1

1.5    to 1.9 times baseline

OR

= 0.3 mg/dl

<0.5 ml/kg/h for

6-12 hours

|2

2.0 to 2.9 times baseline

<0.5 ml/kg/hr for

= 12 hours

| 3

 3.0 times baseline

OR

Increase in serum creatinine to >= 4.0 mg/dl o

OR

Initiation of renal replacement therapy

OR

decrease in eGFR to <35ml/min/1.73 m2 in patient <18 years

<0.3 ml/kg/hr for

= 24 hours

OR

Anuria for >= 12 hours

AKI and Non-AKI groups: The study population will be classified as Acute Kidney Injury (the “AKI Group”) and the “Non-AKI Group” for further outcome/s analysis. The Incidence, Staging, Outcome & Mortality in AKI will be recorded.

Statistical Analysis:

Age, Weight, and Length of PICU stay (days) will be represented as mean (SD) +/-SD, mode & median.

Variables like sex, diagnosis, primary system affected, complications & outcome will be listed as a percentage of total patients enrolled.

AKI: Frequency, Staging (using KDIGO criteria), and Outcome will be recorded as percentages.

Risk factors for AKI (hypovolemia, shock, sepsis, mechanical ventilation, PICU stay >7 days & use of nephrotoxic drugs) will be listed as percentages.

Mortality will be compared between the “AKI Group” & the “Non-AKI Group” by chi-square test.

Predictors of/ factors affecting the mortality & the length of stay (in the “AKI Group” & “Non-AKI Group”) will be analysed by chi-square test.

The mortality and length of PICU stay/ length of hospital stay will be calculated for the “AKI Group” & “Non-AKI Group”.

A P-value less than 0.05 will be considered to be significant.

Expected Outcomes:

This study is expected to help in:

1. Determining the frequency of AKI in PICU for early intervention.

2. Early intervention may help in reducing mortality & LOS.

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