As an equipment reviewer, GP and member of the medical fraternity, I have seen many oxygen saturation monitors.
Years ago, I can remember attaching chunky, grey bulldog clamps to patients' fingers, at the request of my registrar. The unit was connected to a machine the size of a refrigerator, whose sole purpose was to measure oxygen saturation.
It is true to say that the clamp these days is similar, although now comfortable, but there is no longer any need for the gargantuan machine.
Secondary care, of course, still uses shelf-based monitors and there may be some variation in fine point accuracy between stand-alone, mini devices and the hardwired units used in hospital.
Small, neat, portable
In primary care we like things small, neat, portable and easy to use, yet flash and downright cool - and the Onyx II 9500 finger pulse oximeter is all of these and more.
The clamp is sleek and curvaceous and only 3cm x 2cm x 2cm. A teardrop-shaped LED display comprises the saturation counter, pulse monitor and triphasic integrated LED light. The latter informs you if the unit is ready to go, still firing up, or simply dead.
The clamp opens easily for insertion of the index finger. The LED light cycles from yellow to red to green, then flashing green. After four seconds, saturation and pulse rate can be read off the screen.
The Onyx II has a soft pouch, which can slide onto a belt or into the on-call bag. There is also a lanyard, which is simple to attach and lets you hang the monitor around your neck.
The Onyx II could be loaned to patients to monitor their daily saturations, if needed.
The instruction manual (on CD-ROM) is functional and comes in 11 languages.
The pulse oximeter runs on two AAA batteries, which last a long time and are easily replaced. At this point, I should also add a word of advice about keeping the unit clean and safe between patients.
This is straightforward if you follow the instructions - strong detergent or bleach can damage the sensor.
There appears to be a growing indication for using measurement of oxygen saturation in the primary care setting, although there is little definitive published evidence.
In acute asthma, assessment of severity and the effectiveness of oxygen therapy can, in part, be carried out using oxygen saturation monitoring at first contact and while administering treatment.
Oxygen saturation, alongside percentage of predicted and arterial gases (when accessible), backed up by the clinical findings of paucity of chest sounds, skin colour, heart rate and rhythm, respiratory effort (vocalisation assessment) are stated to be useful.
An O2 saturation of >92 per cent breathing air is an essential marker point. Some sources of evidence rate the use of O2 saturation measurement in the clinical assessment of LRTI and this is mentioned in the British Thoracic Society guidelines (April 2004 update) with reference to community acquired pneumonias.
It is far from clear whether this equipment is essential, advisable, or optional. I consider it advisable, erring on the side of caution; besides, it is cool.
- An independent review by Dr Peter Ilves, a GP in London and Medical Director of Primary Solutions (UK)
- Equipment provided by Williams Medical Supplies