12 Monitoring Invasive Pressure
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Calculating Cerebral Perfusion Pressure
The monitor can calculate the difference between mean arterial pressure and the intracranial pressure.
The difference is labeled CPP.
1 In the Main Setup menu, select Measurements.
2 Select CPP.
3 In the Setup CPP menu, select which arterial pressure source should be used in the calculation.
Calculating Pulse Pressure Variation
Note: Pulse Pressure Variation can be calculated in two different ways on this monitor - directly from
the pressure measurement or in conjunction with the CCO measurement. Refer to the Cardiac Output
chapter for information on PPV from CCO. Only one PPV can be active at a time.
Pulse Pressure Variation (PPV) is calculated from beat-to-beat arterial pressure values. Pulse pressure
is the difference between the systolic and the diastolic pressure values for a single beat. Pulse pressure
variation is defined as the maximal pulse pressure less the minimum pulse pressure divided by the
average of the two. The average variation in pulse pressure is calculated over periods of 32 seconds.
WARNING
• This monitor can calculate PPV from beat-to-beat values of any arterial pulsatile pressure. The
circumstances under which the calculation of a PPV value is clinically meaningful, appropriate and
reliable must be determined by a physician.
• The clinical value of the derived PPV information must be determined by a physician. According
to recent scientific literature, the clinical relevance of PPV information is restricted to sedated
patients receiving controlled mechanical ventilation and mainly free from cardiac arrhythmia.
• PPV calculation may lead to inaccurate values in the following situations:
– at respiration rates below 8 rpm
– during ventilation with tidal volumes lower than 8 ml/kg
– for patients with acute right ventricular dysfunction ("cor pulmonale").
• The PPV measurement has been validated only for adult patients
To select an arterial pressure as PPV source:
1 In the Main Setup menu, select Measurements.
2 In the Setup PPV menu, select ABP, ART, Ao, BAP, P or FAP as the arterial pressure source.
CAUTION
Older Multi-Measurement modules cannot supply a beat-to-beat arterial pressure value. In this case the
monitor shows a
No PPV from MMS or No PPV from FMS INOP.
unable to calibrate - perform
zero first
No valid zero. Zero the transducer.
Message Corrective Action
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