OxyLite User Manual
Revision 1.1 | May 2015
23
3.8
Placement of Sensors in Vivo or in Vitro
Please note that detailed guidelines for the use of sensors in a variety of
tissue monitoring applications are maintained on our dedicated support site:
http://www.oxford-optronix.com/support/supp_oxylite.htm
In summary:
Depending on sensor type, the oxygen-sensitive region is located either at
the very tip (‘bare-fibre’ sensors), or slightly posterior to the tip (‘NP/O’ and
‘LAS’ sensor types).
For
in vitro
environments (e.g. cell culture) the placement of sensors
generally simply requires the direct exposure of the sensor tip to the fluid of
interest. Brief measurements can be carried out by hand; a miniature
clamping apparatus or any other type of jig can be used for longer term
measurements.
The optimum approach for introducing sensors into biological tissues (
in
vivo
use) will depend on the sensor type, the tissue to be studied, the size
of the animal model, the nature of the application and the personal
preferences of the user. In general we recommend the use of suitable
catheter introducers as the majority of sensor types are insufficiently robust
for direct tissue insertion.
3.9
Temperature Compensation
The luminescence-based oxygen monitoring technology employed by the
OxyLite is sensitive to temperature.
The error in the pO
2
reading due to a discrepancy between the temperature
at the site of measurement and the temperature at which the sensor was
calibrated (37°C) is dependent upon:
The temperature range in question,
The current pO
2
reading.
It can be approximated as follows.
For measurements in the range 30 - 45°C
, the error in mmHg will be
(1.2%) x (temperature discrepancy (i.e. temp error), in °C) x (displayed pO
2
reading in mmHg).
CAUTION
The oxygen-sensitive region of sensors must be isolated from
atmospheric oxygen to ensure reliable
in situ
oxygen
measurements.