1.
Mercury Manometer
a) Definitive pressure reading
b) Easy observe oscillations
c) Requires no power source
d) Limited to approx 400 mmHg
e) Low pressure area of pump
f) No zero drift
g) Gives direct aortic mean pressure
h) More accurate measurement of pump occlusion
i) No alarm status
j) Cannot measure negative pressure
2.
Aneroid (‘a-neros-without liquid’) Gauge
a) Requires no power source
b) Able to measure higher pressures than mercury manometer
c) Drift of zero during pulsatile flows (not designed for pulsatile flows)
d) No alarm system to turn off pump
e) Cannot measure negative pressure
3.
Electronic Pressure
Monitor
a)
Jostra Pressure
monitor
i) Designed to measure arterial pressures and cardioplegia pressures in heart-lung machine
ii) Activates an alarm at low & high pressure limits set by limit indicators
iii) Alarm activates an alarm signa which can stop the blood pump
iv) Built in transducer
v) 12V DC; max 3 W consumption
vi) Range -50 to 450 mmHg; -100 to 900 mmHg
vii) ‘Unlatched’ alarm system
viii) Maintenance
a) An external reference pressure instrument is required to check its accuracy
b)
Electronic diaphragm
transducer system
c)
Sarns 8000
i) ‘Alert’ & ‘Alarm’ states
ii) User-set alerts & alarms warn of impeding overpressure with visual and audio signals or actually stops the pump
iii) The system retains the settings & recalls them after the next power up
iv) ‘Latched’ alarm system; requires restarting of pump module after alarm state
v) Range -45 to 990 mmHg
vi) Uses transducers
vii)
Disposable
viii)
Non disposable
(Wheatstone bridge)
ix) Can measure a higher pressure
x) Must be calibrated
1.
Isolators
a) Ensure is properly primed; devoid of air
b) Must be predominantly empty of pump fluid prior to connection to transducer - otherwise membrane may become taut & not indicate true pressure
c) Prevents contamination of transducer & sterility of circuit
2. Filters
a) Hydrophobic type
b) Seen on dialysis machines
c) May become blocked