In emergency department patients requiring resuscitation room care, can Renal Resistive Index measurements predict the development of acute kidney injury?

  • Heather Venables

Student thesis: Doctoral ThesisDoctor of Health (DHealth)


PURPOSE: Doppler renal resistive index (RRI) has emerged in the last decade as a useful prognostic indicator for transient (fluid responsive) and persistent acute kidney injury (AKI). The determinants of RRI are largely systemic and recent studies confirm that RRI measurement could also be a useful early marker for sub-clinical AKI and post procedural AKI risk. This study aimed to determine the feasibility of RRI measurement in an Emergency Department (ED) resuscitation room setting using a point­of­care ultrasound system.

METHODS: In this prospective single centre study, RRI measurement was attempted in 20 non-consecutive patients (meeting the inclusion criteria) by a single expert sonographer. RRI measurements were evaluated against context specific feasibility criteria and target outcomes.

RESULTS: 20 patients (11 male, 9 female) were recruited to the study. Age of patients ranged from 33 years to 91 years (mean 62.3 years). Adequate visualisation of both kidneys was achieved in 60% of patients (n=12). In patients where it was not possible to achieve adequate views of both kidneys (n=8), limiting technical factors were shortness of breath (SOB) (n=6), high BMI (n=2). At least one measurement of RRI was achieved in 70% of patients (n=14). However, in 9 of these patients (64.3%) the Doppler spectral traces achieved were substandard and did not meet the measurement criteria for RRI as specified in the study protocol. In 30% of patients (n=6) no usable spectral trace was achieved and it was not possible to measure RRI. SOB was noted as a technical difficulty in 60% of patients (n=12) including three for whom RRI measurements were achieved. In 9 patients (45%) SOB was recorded as the primary reason for failure to acquire a usable Doppler trace. All criteria for RRI measurements were met in only 3 patients (15%).

Measurement of RRI was not feasible in patients requiring resuscitation room care using a current point of care ultrasound system. If RRI is to play a useful role in this high priority patient group, adaptation of the available technology is required to mitigate the problem of image blur due to patient breathing movement.

KEYWORDS: Acute kidney injury; Doppler; Resistive index; Feasibility; Emergency Department
Date of Award13 Feb 2019
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorManuchehr Soleimani (Supervisor) & Iain Lennon (Supervisor)


  • Acute kidney injury
  • Doppler
  • Resistive index
  • feasibility
  • Emergency Department

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