Description of two new nomogram/calculators for categorising oxygenation status

Abstract

Presentation of blood gas results requires knowledge of the position of the oxygen dissociation curve (ODC) to give a complete indication of oxygenation status.

Many computations rely on the shift of the ODC occuring with a constant proportional value throughout its length, with no change of shape. If this consistency is accepted it permits geometric manipulation of the curve and the construction of accurate hand held mechanical calculators.

Two examples of such calculators are presented. From the measured values of oxygen partial pressure, saturation and haemoglobin concentration they will present many of the new proposed units.

Key Words:

• Blood oxygenation
• blood gases
• oxygen saturation
• haemoglobin-oxygen dissociation curve
• nomograms.