RSA Talk in Focus: Can bioimpedance measurements improve renal care?

 
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Guest speaker Dr Elizabeth Lindley, a well-known clinical scientist from Leeds Royal Infirmary (UK) discusses bioimpedance spectroscopy at a RSA guest lecture.

Overhydration is one of the major factors in the development of cardiovascular diseases and has been shown to be the second strongest predictor of mortality among dialysis patients, only after diabetes.1

In 2008 Fresenius Medical Care Australia launched the Body Composition Monitor (BCM), a small portable device that determines individual fluid status and body composition in an easy and objective way. The BCM employs the latest bioimpedance spectroscopy which provides a non-invasive and accurate measurement that is obtained in just 2 minutes.

At this year’s Renal Society of Australasia (RSA) Conference which took place in Hobart, Tasmania from 5th - 8th June 2013, Dr Elizabeth Lindley, a well-known clinical scientist from Leeds Royal Infirmary (UK), demonstrated her special interest in bioimpedance spectroscopy at a RSA guest lecture. Dr Linley’s key outcomes:

  • The BCM measurement is quick to perform, and gives instant results which benefit both the nurse, as they can assess the patients fluid status and also using this as a teaching aid to show patients their weight gain is fluid and not muscle
  • The BCM can be used in the patient’s home, clinics or satellite units, where access to medical staff maybe limited, so nurses have another tool to assess a patient’s fluid status.

Having performed over 1000 BCM measurements with patients at Leeds, she was able to share with the audience her professional tips to obtain the most precise measurements for a whole range of patients. Her key tips:

  • Apply alcohol gel to the patient’s hand and foot prior to applying the BCM electrodes, as this improves the contact between the electrode and the skin improving the reading quality of the measurement
  • Patients to assume the stick man, or gorilla position, to improve reading quality and to prevent the current taking the shortest route from limbs to the trunk
  • No need to remove hand rings, as these are not in the area where the current will pass
  • Patients must be in the supine position for at least 2 mins prior to performing a reading.

Dr Lindley also explained the functional principal of the BCM, including the important physics component so the audience had a better understanding of how the BCM reaches the results. If you would like to know more about this area, please contact us here.

The device displays the results as a “rainbow” on the results screen, whereby the location of the rainbow on the screen is important as this gives relevant information regarding the fluid status of patients. Dr Lindley and staff refer to the Cole Cole plot on the results screen as the rainbow. Ideally the rainbow should be a nice clear curve in the centre of the display, and breaks in the curve would indicate the patient has moved. Patients who are dehydrated will tend to have rainbows which appear more on the left side of the screen.

Dr Lindley’s enthusiasm for the BCM was infectious, as she presented case studies on how she and her team have used the BCM to maintain the fluid status of patients in their ideal range. Some HD patients routinely come off even below their target weight to reduce the intradialytic fluid gain. One of the cases she presented, the patient was able to come off dialysis due to an improvement in Glomerular Filtration Rate (GFR) that was attributed to an improvement in Residual Renal Function (RRF) due to maintenance of hydration status using the BCM. Another of the cases presented outlined the importance of following tissue and body mass parameters in order to provide adequate nutrition following prolonged ICU admission.

Fresenius Medical Care also took the opportunity of asking Dr Lindley to speak to the team at the Geelong Renal Unit in Victoria as they are about to commence a trial of the BCM. It was standing room only in the meeting room as the time came for the clinical scientist to talk. The insightful presentation was rounded up by a “live demonstration” of the BCM on a home dialysis patient. Here are Dr Lindley’s most important messages:

  1. It is important to do more than one reading
  2. If you get an unusual result, it’s okay. Do a second reading, or wait and perform a reading the next time the patient is available
  3. BCM is an excellent tool to support clinical staff in the fluid management of dialysis patients.

For more information about how BCM might be useful in your clinic, please click here.

Acknowledgement: Fresenius Medical Care Australia sponsored Dr. Elizabeth Lindley from Leeds Royal Infirmary in the UK, to attend this years’ RSA conference in Hobart as a keynote speaker.

References

  1. Wizeman V, et al. The mortality risk of overhydration in haemodialysis patients. Nephrol Dial Transplant. 2009; adv