Published Aug 21, 2004
gwenith, BSN, RN
3,755 Posts
How many of us have struggled with less than satifactory pen lights. swollen slippery eyelids, bright lights in the units and dark coloured irises trying to see the pupil reaction??? I know I have and finally someone has done something about it.
Crash victims' head injuries spotted by 'pupilometer' 19:00 18 August 04A hand-held device that measures the contraction of the pupils of accident victims in response to bright light will help to ensure they get the correct treatment.When paramedics are called to an accident one of the first things they do is shine a light in the eyes of the survivors to see how their pupils react. If they contract sluggishly the person may have serious head trauma. Extra pressure in the brain caused by internal bleeding constricts the nerve that controls the pupil's response to light. Eye to eyeBut spotting changes in the pupil's responsiveness is difficult, particularly when different doctors and nurses take measurements at different times."It is one of the only physiological parameters which still relies upon manual assessment," says Andrew Clark, a medical technologist at Newcastle upon Tyne Hospitals NHS Trust in the UK and a member of the team that developed the new device.To record the pupils' reaction, doctors compare their size with a standard chart and classify the speed of the change as fast, slow or non-existent. But the technique is time-consuming and extremely subjective.Accident scene "At the moment you get a paramedic waving a torch at the victim on a wet dark road," says Alan Wenman of Medical Device Management in Braintree, Essex, the UK company that built the commercial pupilometer.It comprises a digital camera, two infrared light-emitting diodes (LEDs), an ordinary light bulb, a microprocessor and a liquid-crystal display (LCD). To take a reading, the user holds it within 28 millimetres of the eye for less than a second.The device's main advantage is that it does not touch the patient's body. There are other pupilometers on the market, but these are either not portable or use a cup that fits around the eye.For hygiene reasons, this has to be discarded after one use, making the instrument inconvenient to use at an accident scene. Paramedics using the new pupilometer will be able to take accurate measurements that can then be sent ahead to the hospital.It records a short video of the eye before, during and after a 200-millisecond flash of white light. Infrared video is used to record any changes because the pupil is not affected by this wavelength of light.Subtle changes Image-processing software identifies the pupil and displays changes in its diameter as a graph of size against time. It works out where the pupil is by identifying the largest circular, or near-circular, dark region in its view
Crash victims' head injuries spotted by 'pupilometer'
19:00 18 August 04
A hand-held device that measures the contraction of the pupils of accident victims in response to bright light will help to ensure they get the correct treatment.
When paramedics are called to an accident one of the first things they do is shine a light in the eyes of the survivors to see how their pupils react. If they contract sluggishly the person may have serious head trauma. Extra pressure in the brain caused by internal bleeding constricts the nerve that controls the pupil's response to light.
Eye to eye
But spotting changes in the pupil's responsiveness is difficult, particularly when different doctors and nurses take measurements at different times.
"It is one of the only physiological parameters which still relies upon manual assessment," says Andrew Clark, a medical technologist at Newcastle upon Tyne Hospitals NHS Trust in the UK and a member of the team that developed the new device.
To record the pupils' reaction, doctors compare their size with a standard chart and classify the speed of the change as fast, slow or non-existent. But the technique is time-consuming and extremely subjective.
Accident scene
"At the moment you get a paramedic waving a torch at the victim on a wet dark road," says Alan Wenman of Medical Device Management in Braintree, Essex, the UK company that built the commercial pupilometer.
It comprises a digital camera, two infrared light-emitting diodes (LEDs), an ordinary light bulb, a microprocessor and a liquid-crystal display (LCD). To take a reading, the user holds it within 28 millimetres of the eye for less than a second.
The device's main advantage is that it does not touch the patient's body. There are other pupilometers on the market, but these are either not portable or use a cup that fits around the eye.
For hygiene reasons, this has to be discarded after one use, making the instrument inconvenient to use at an accident scene. Paramedics using the new pupilometer will be able to take accurate measurements that can then be sent ahead to the hospital.
It records a short video of the eye before, during and after a 200-millisecond flash of white light. Infrared video is used to record any changes because the pupil is not affected by this wavelength of light.
Subtle changes
Image-processing software identifies the pupil and displays changes in its diameter as a graph of size against time. It works out where the pupil is by identifying the largest circular, or near-circular, dark region in its view
Full story here:- http://www.newscientist.com/news/news.jsp?id=ns99996291
nuttyRN
20 Posts
How many of us have struggled with less than satifactory pen lights. swollen slippery eyelids, bright lights in the units and dark coloured irises trying to see the pupil reaction??? I know I have and finally someone has done something about it.Full story here:- http://www.newscientist.com/news/news.jsp?id=ns99996291
Our neuro docs always say if you see a change in the pupils you better have called me a lot earlier. (I do work on a neuro unit) This is the last thing they want to hear
True but if you have a patient that is sedated and ventilated that is often ALL you can see. There are a couple of conditions that will affect the pupil size early otherwise I agree it is a late sign. The ones that affect the pupils early are of course bleeds in and around the optic chiasma.
My patients are post-intubation; they have been moved to the neuro floor! But pupillary changes do occur a lot, and we do not always call the MD- :imbar :imbar
Katnip, RN
2,904 Posts
I want one. Sometimes it's so hard to assess pupillary reaction when they come rolling in the door. ESPECIALLY those with really dark eyes in a dark room.
I hear you cybecat actually what I found helps is holding the torch a little off to the side so that you don't get the reflection of the light itself on the cornea making it more difficult to see the reaction which can be quite subtle. Also sometimes looking at the actual iris for activity rather than the pupil itself can give you a better indication of reaction in really dark brown eyes.
Yes but there is still too much emphasis put on pupil changes and some of that is the paucity of information out there.
The one good reliable Neuro nursing book - Hickey tends to emphasise that there are only a few really significant changes and those are usually blatant. Having said that - yes a pupil change to ovoid shape is a very early indicator of increased ICP but it is transient and difficult to detect. Bleeds/oedema in and around the optic chiasma tend to produce more pronounced differences in pupil size.
The classic sign of unequal pupils caused by uncal herniation is a late sign in head injury and usually associated with epidural bleeds - and your neurosurgeons is right - if that happens they will have wanted to be called long before - when the patient first started to deteriorate neurologically.