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Abstract: TH-PO226

Pilot Study to Measure Indicators of Blood Flow in the External Auditory Meatus During Haemodialysis

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • Yoowannakul, Suree, Bhumibol Adulyadej Hospital, Bangkok, Thailand
  • Leung, Terence, University College London, London, United Kingdom
  • Davenport, Andrew, Royal Free Hospital, London, United Kingdom

Intradialytic hypotension remains the most common complication of outpatient haemodialysis (HD) sessions. As such, there is a need to develop non-invasive monitoring devices, which would then allow for therapeutic interventions to prevent hypotension. We report on a pilot study monitoring indicators of blood flow in the outer auditory meatus.


We measured the maximum pulse wave amplitude and indicators of blood flow by red and green pixel values in the outer auditory meatus from video recordings made using an otoscope fitted with a digital camera in adult patients undergoing haemodialysis treatments.


We studied 61 patients, 43 (71.5%) male, mean age 64.9 ± 12.7 years during their dialysis session. Weight fell from 72.8±22.5 pre-dialysis to 71.5±22.1 kg post-dialysis (p<0.001). Blood pressure did not significantly change (pre-dialysis 142±29/ 67±18 to 143±25/68±17 mmHg post-dialysis). The maximum pulse wave amplitude in the external auditory meatus fell from 0.21 (0.1-0.55) to 0.14 (0.04-0.4) after 90 minutes, p<0.001, and remained low thereafter, and the change at the end of the dialysis session was associated with percentage weight loss (r= -0.37, p=0.003). Green and red pixel values did not change (pre-dialysis 0.339 (0.333-0.345) to 0.302 (0.291-0.33) post, and 0.301 (0.293-0.328) pre-dialysis to 0.339 (0.334-0.347), respectively).


This pilot study showed that the maximum pulse wave amplitude measured in the external auditory meatus fell during the dialysis session, and that the fall was associated with fluid removal. This could potentially lead to the development of a monitoring device which could fit in the ear and record during the dialysis session.


  • Private Foundation Support