Dräger Primus - Page 82

Monitoring
Age-corrected MAC values are calculated according to
W.W. Mapleson (British Journal of Anaesthesia 1996,
pages 179-185), whose formula only applies for patients
>1 year old:
MAC = MAC 40 x 10 (-0:00269 x (age — 40))
The formula shows the reciprocal relationship existing
between MAC and age.
Age 1 is used for calculation if the age is "<1".
Example:
Expiratory concentrations of 0.9 Vol.% isoflurane and
50 Vol.% N2O are measured for a 60-year-old patient.
1 MAC isoflurane at 60 years equals 1.01 according to the
formula above.
1 MAC N20 at 60 years equals 92.4 according to the formula
above.
The total MAC factor is calculated as follows
0.9 Vol%lso___ , __ 50 Vol.% N20
1.01 (MAC Iso) 92.4 (MAC N20)
= 1.4
In other words, 1.4 MAC are obtained with the current
concentration. For a 20-year-old patient, the same
concentration yields an MAC factor of 1.1.
Virtual flow tubes
@ indication of the individual flows actually delivered by the
fresh-gas mixer.
Lung compliance (CPAT)
@ Determined from PLAT and expiratory VT.
Lung compliance is equal to the measured total compliance
Gua) Minus the system and hose compliance determined in
the self test.
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Instructions for Use Primus SW 2.n