Table of Contents
Advertisement
Technical Discussion
Measured versus Calculated Saturation
SatSeconds Alarm Management
126
carboxyhemoglobin or methemoglobin. In contrast, hemoximeters such as the
IL482 report fractional saturation -- oxygenated hemoglobin expressed as a
percentage of all measured hemoglobin, including measured dysfunctional
hemoglobins. To compare functional saturation measurements to those from an
instrument that measures fractional saturation, fractional measurements must be
converted as follows:
functional saturation =
When saturation is calculated from a blood gas partial pressure of oxygen (PO
the calculated value may differ from the SpO
This usually occurs because the calculated saturation was not appropriately
corrected for the effects of variables that shift the relationship between PO
pH, temperature, the partial pressure of carbon dioxide (PCO
fetal hemoglobin. See Figure 21.
Figure 21: Oxyhemoglobin Dissociation Curve
The N-595 utilizes Nellcor SatSeconds alarm management technique. SatSeconds
is a function of the software within the N-595. With the SatSeconds technique,
upper and lower alarm limits are set in the same way as traditional alarm
management. The clinician also sets a SatSeconds limit that allows monitoring of
%SpO
below the selected lower alarm limit for a period of time before an audible
2
alarm sounds. Refer to the N-595 Operator's manual for managing SatSeconds.
fractional saturation
100 - (% carboxyhemoglobin + % methemoglobin )
measurement of a pulse oximeter.
2
x100
),
2
and
2
), 2,3-DPG, and
2
Advertisement
Table of Contents
