Shock news: Laser breath test

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  • Published: Aug 15, 2016
  • Author: David Bradley
  • Channels: Atomic
thumbnail image: Shock news: Laser breath test

Laser shock

Molecular Flow Sensor (MFS) records oxygen consumption in real time for critically ill patients with shock. Credit: University of Oxford

A new device that brings together laser spectroscopy and precise flow measurement of breath can be fitted to a standard ventilation tube for hospital patients with shock in critical care.

The care of critically ill patients in hospital with life-threatening shock could be improved enormously if there were a way to monitor their breath and more specifically oxygen consumption in real time. The first successful tests of a new device by researchers at the University of Oxford, United Kingdom, could see such an improvement become a reality.

Colloquially shock is associated with a person being frightened or being in a state of disorientation following a trauma such as a car crash. However, in medical terms shock has a very precise definition, it is an acute, and potentially life-threatening, condition associated with a sudden large drop in blood pressure by whatever cause. Various physical trauma, biochemical changes or sudden emotional stress can cause a rapid fall in blood pressure, including loss of blood through injury, severe burns, an allergic reaction, heart failure, and sepsis. Patients will generally present with cold, pallid skin, irregular breathing, rapid pulse, and dilated pupils, and must be treated as an emergency case and their condition monitored carefully while treatment, including medication, oxygen, and sometimes a blood transfusion, is given. Otherwise the low blood pressure leads to organs and the whole body receiving inadequate oxygen and ultimately the deterioration and subsequent failure of organs.


Now, Peter Robbins of the Department of Physiology, Anatomy and Genetics and chemists Grant Ritchie and Gus Hancock have developed a new technology for monitoring patients with shock. The research was publicly funded through the NIHR Oxford Biomedical Research Centre and the UK's Medical Research Council.

"This is the culmination of many years of development and it has finally come to fruition," says Robbins, who led the research. "It is exciting for us to be able to offer something to doctors that has the potential to improve significantly the care of very sick patients." At the moment healthcare workers have no way of directly measuring how much oxygen the patient's body is using, which in turn makes it very difficult to assess whether or not the treatment being given is having a positive effect or not.

Hospital monitoring

The researchers carried out tests of the new system with healthy volunteers and in patients being given an anaesthetic at Oxford's John Radcliffe Hospital. The results indicate that the accuracy available with this device is better than anything previously achieved. The team published details in the journal Science Advances.

Stuart McKechnie is a Consultant in Intensive Care at the hospital and had this to say: "Though we already monitor critically ill patients very closely, this device promises to provide highly useful additional information that may help us to care better for patients with sepsis and shock in the future." The laser breath test device is now being used in a wider study in the Intensive Care Units within Oxford University Hospitals NHS Foundation Trust, which runs the John Radcliffe Hospital.

"The device works by essentially counting the number of oxygen molecules which enter the lungs, and counting the number breathed out," Ritchie told SpectroscopyNOW. "Laser absorption spectroscopy is used to measure concentrations of oxygen, carbon dioxide and water vapour across a standard ventilation tube every 10 milliseconds. This is combined with precise measurements of gas flow to deduce the rate of oxygen consumption in real time with unprecedented precision. Low power near infrared diode lasers are used for the concentration measurements, with cavity enhanced absorption spectroscopy probing the weak oxygen transition," he adds.

Related Links

Sci Adv 2016, 2, e1600560: "In-airway molecular flow sensing: A new technology for continuous, noninvasive monitoring of oxygen consumption in critical care."

Article by David Bradley

The views represented in this article are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd.

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