An observational study to compare the renal resistive index in postoperative shock versus non-shock patients

Study will be conducted after the approval from the institutional ethical committee and

registration with Clinical Trials Registry of India (CTRI). Patients fulfilling the inclusion

criteria will be recruited for the study. A written and informed voluntary consent will be

obtained from the patient or next to kin, after carefully explaining the procedure, its benefits

and risks in his/her vernacular. Any postoperative patient who will develop hypotension in ICU

will be treated as per standard protocol and if hypotension will not be corrected within first

three hour of resuscitation, then the first value of renal resistive index will be measured between

first 3 to 6 hours of development of shock. Renal resistive index of the patients will be measured

with SonositeTM Edge II Total portable ultrasound machine and P19 phased curvilinear array

probe (2-5MHz) in supine position. The probe will be placed in posterior axillary line to get an

image of kidney. RRI will be measured from interlobar or arcuate arteries adjacent to medullary

pyramids. Three sequential reading from upper, median, lower lobe will be taken and its

average will give the final RRI. RRI is calculated by the formula:

RRI= (peak systolic velocity-end diastolic velocity)/peak systolic velocity

IVC measurement will be done in short axis view with phased array probe(1-5MHz) in supine

position in short axis view. The difference between IVC measurement during expiration (IVCE)

and IVC measurement during inspiration (IVCI) and IVC collapsibility index will be calculated

as IVCE-IVCI/IVCE to assess intravascular volume in relation to the central venous pressure.

Cardiac Index (CI), Pulse Pressure Index (PPI) will be seen from Edward VIGILEO monitor

and transducer, connected to FLOTRAC sensor. FLOTRAC sensor will be connected to the

radial artery catheter of the patients The sensor will be placed at the level of right atrium before

pressure equilibration(zeroing).

Following details will be noted from patients:

1. Age

2. Gender

3. APACHE II score

4. SOFA score

5. Inferior vena cava diameter and collapsibility with respiration.

6. Risk factors for AKI like sepsis, hypotension & diabetes.

7. Renal function assessed with pre admission creatinine, eGFR

8. Urinary indices like FENa, FEurea, albumin/creatinine ratio

9. Daily measurement of change in hemodynamic parameters like HR, MAP, PPI, CVP, CI,

vasopressors dose, serum lactate, serum urea, serum creatinine, urine output and RRI up to 3

days