Oxygen Analyzer

Oxygen is the most commonly used drug in the NICU. Inappropriate oxygen therapy affects the outcomes of neonates. Too little oxygen (Hypoxia) results in higher mortality and neuro-developmental sequelae. Too much oxygen results in ROP and BPD. Hence oxygen analyzer or FIO2 monitor is desirable which helps in analyzing oxygen concentration delivered to the babies.
FIo2 analyzer measures the concentration of oxygen in the inspired air. It has galvanic cell with long half life and quick response time. Galvanic sensor is an electrochemical sensor which is a small partially sealed cylindrical device that contains two dissimilar electrodes immersed in aqueous electrolyte KOH.
As oxygen diffuses through semi-permeable membrane installed on one side of sensor, the oxygen molecule at cathode gets reduced to form positively charged hydroxyl ion. This hydroxyl ion migrates to the sensor anode where an oxidation reaction rakes place. Oxidation –Reduction reaction generates electric current proportional to oxygen concentration in the sample gas. The current generated is measured and conditioned with external electronics and displayed on digital meter in percent.
When power switch is on sensor is exposed to air indicating 21%. If it does not show 21% then the control is rotated so that it reads 21%.
After calibration, place the sensor in gas mixture whose concentration is to be measured and then read the displayed value, which is the concentration of oxygen.
This is extremely small and fragile equipment and the sensor is very expensive and important component of the Analyzer. Do not pull or bend the sensor. Always calibrate before measurement. Do not leave oxygen monitor stored with power switch on. Sensor fluid will freeze at low temperature and ignite at high temperature hence avoid high or low ambient temperature where the FIO2 machine is kept.
  • Introduction...
  • 1. What is oxygen ...
  • 2. What is its pri...
  • 3. How to calibrat...
  • 4. How to use?...
  • 5. What precaution...
 

Introduction

DR. SANDEEP KADAM
MD, DM (Neonatology)

Associate Consultant Neonatologist
Department of Pediatrics
KEM Hospital
Pune

1. What is oxygen analyzer?

► An equipment which analyses oxygen concentration being
    delivered to the neonate

► Small cylindrical device consisting of a galvanic cell with
    sensor

► Galvanic sensor has two dissimilar electrodes in aqueous
    electrolyte KOH

2. What is its principle?

► Oxygen diffuses from one side of sensor through
    semi - permeable membrane

► Oxidation – reduction reaction generates electric current
    proportional to oxygen concentration

► Current generated is measured and conditioned with
    external electronics and displayed on digital meter

3. How to calibrate?

► Switch on the analyzer and expose the sensor to the
    atmosphere

► Displayed value should be 21%

► If it does not, control knob is rotated till it reads 21%

► The instrument has an accuracy of ± 2%

4. How to use?

► After calibration, place the sensor inside oxygen hood
    away from the oxygen inflow end of the tubing

► Wait for 5-20 seconds as this is the usual time between
    placement and detection of the reading (Response time)

► Displayed value is the concentration of oxygen

5. What precautions should be taken?

► Do not pull or bend the sensor

► Always calibrate before measurement

► Do not leave oxygen monitor stored with power switch on

► Avoid high or low temperature to prevent damage to the
    sensor fluid