The Extreme Tachycardia delta value will retain its adjusted value as the HR high alarm limit
setting is adjusted downward, but will begin to shrink in value as the high alarm limit setting is
adjusted closer to the alarm limit maximum.
Desat Alarm Setting
The Desat alarm setting is restricted to a maximum value that is 2 less the SPO2 low alarm limit
setting, while the minimum setting can be as low as the alarm minimum. See page 6‐11 for setting
As long as the SPO2 parameter is on, the Desat alarm value will retain this setting even if the func‐
tion is turned off and on.
The SPO2 alarm adjustments are designed to give priority to the Desat alarm setting. Therefore,
the SPO2 low and high alarm limits may also be adjusted based on a change made to the Desat
alarm setting. Whenever the Desat alarm setting is changed, the following rules determine the
lower and upper SPO2 alarm limits:
Setting Alarm Limits Globally
Global changes to all of the lower and upper alarm limit settings can be made automatically by
pressing the using the 1‐Touch Alarms key. These global changes are calculated using
percentages selected in the 1‐Touch High % and the 1‐Touch Low % options; see page 4‐17.
During calculations if a patient's monitored value is so high or low that it would exceed the alarm
limit range for the parameter, then the alarm limit will be set to the highest or lowest possible
value but not off, as indicated in the table on page 4‐22. For example, if after pressing the 1‐
Touch Alarms key, a patient's SPO2 upper alarm limit setting was 99 (the highest allowable
value), then an alarm will be generated if the patient's reading reaches 100. (To turn off an alarm
limit, see Setting Alarm Limits Individually on page 4‐13.)
Also note that setting alarm limits globally may result in a lower SPO2 alarm limit than the
default setting. For a patient that has an SpO2 reading of 99%, the new upper limit will be 99 but
the new lower limit will be 79 (instead of 85) at a 1‐Touch High % of 20 (factory default).
4‐12 Alarms Expression MR400 Instructions for Use
If the Desat alarm was turned on after being set and turned off, then if the last set value of
the SPO2 low alarm limit is less than the Desat alarm setting plus 2, the SPO2 low alarm
limit will be set to the Desat alarm setting plus 2.
If the Desat alarm is adjusted upward so that the setting is greater than or equal to the
SPO2 low alarm limit minus 2, then the SPO2 low alarm limit will be increased by the
system such that the Desat alarm setting plus 2 is always maintained (i.e., the low alarm
limit will always move to stay two greater than Desat alarm setting). If low alarm limit is
altered due to this scenario, low alarm limit will retain this altered value even if the Desat
alarm setting is adjusted downward.
The SPO2 high alarm limit will be adjusted as necessary in relation to the low alarm limit as
per the normal behavior of low and high alarm limits.
The SPO2 low alarm limit will be allowed to be adjusted downward only until it is equal to
the Desat alarm setting plus 2. No further downward adjustment of low alarm limit will be
allowed until the Desat alarm setting is adjusted downward.