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Biomedicus
540 Bioconsole |
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Design |
Internal motor drives a magnet which is isolated from the Bio-pump magnet by a clear plastic cover; external drive unit also available |
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Maximum revs &
swept stroke |
0 — 4500 RPM Relationship of volume output per revolution unclear - is dependent on resistance (afterload) |
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Disposable pump
heads |
BP-80 (adult) Prime: 80 ml 3 rotator cones Max 10l/min Uses electromagnetic flow probe Capiox SP Prime: 45ml Max speed 3000 rpm Max flow: 8L/min Impeller blades ?Increased blood turbulence & temperatures but offset by reduced rpm required Delphin 3M Uses a doppler flow probe Impeller pump (blades) Small priming volume Generates more Heat (as is small) - more blood trauma |
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Rev counters &
flow indicators |
Digital & LED bar display Electromagnetic versus Doppler |
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Flow transducers |
Observe Gain number; ensure flow probe is connected in correct flow position or will indicate negative flows Electromagnetic flow meter: uses electromagnets to generate an electric field & small electrodes in direct contact with the blood to measure the induced voltage. The probe uses a disposable fluid path utilising a permanent component (housing the electromagnet) that clamps around a special tubing connector containing electrodes moulded into the connector to contact the blood Note: Inaccurate <1000ml/min Doppler (Delphin) |
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Indicators of
‘running hours’ |
Back panel near power inlet |
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Ventricular support |
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Manual crank
mechanism |
Provides manual power to Bio-console during AC or DC failures or during patient transportation; up to 5000 rpm 4 - 1 geared with rpm counter |
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Biomedicus
540 Bioconsole |
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Resettable fuses |
Power circuit breakers: [AC Power; 28V; Battery] located on tilting door within front panel |
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Slave control of
pump by pressure & low level alarm |
Audible only Cannot have a stopping mechanism as will continue to have flow (backwards flow) |
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Runaway control
alarms & protection |
Not relevant |
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Pump direction
safety switches |
Backward flow indicator |
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Safety pump covers |
Two control panels located on tilt down doors which may be closed during operation to eliminate visual clutter and protect from spills |
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High & low flow indicator status |
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Cannot turn off AC as will have back up DC |
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Biomedicus
540 Bioconsole |
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Tubing occlusion
Adjustment |
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Flow rate
Calibration |
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Pump rotation |
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General pump
operations |
DC brushless motor requires minimal servicing |
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Overspeed detection |
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Lubrication |
Prelubricated at factory; requires no further lubrication |
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Cable check |
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Fan Guard check |
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Leakage current |
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Battery check |
Test by removing AC current and operating at full RPM - battery status indicator should remain green; batteries charge when running on AC current |
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Check alarm functioning Battery tests Pressure transducer validity |
1. Flow rate affected by preload & afterload
2. Retrograde flows down arterial line with associated potential air entrainment if inadequate RPM
3. Centrifugal pumps operate by creating pressure thus flow rates are dependent on patient pressure & resistance in the circuit
4. For forward flow to occur, the pressure in the pumphead (PP) must be greater than the combined patient pressure (PPT) and the pressure head (PH) {hydrostatic pressure}.
5. Retrograde flow can create a ‘haemodynamic siphon’ which may result in exsanguination or air embolisation
6. PP > PPT + PH Þ forward flow
7. Ensure pump head is well seated - risk of whole pump head spinning & damaging outlet connector of pump head
Centrifugal Pump1. Popular for ECMO 2. Cannot pump large quantities of air 3. Allow blood propulsion without concern about the disastrous effects of undetected, inadvertent outflow or inflow occlusion of the pump 4. Centrifugal pump stalls whenever occlusion occurs without generating high suction or outlet pressure 5. Does not require a continuous perfusionist presence 6. Haemolysis & other damage to formed blood elements is less to that encountered with roller pumps 7. Decreased entrainment effect 8. Reduced wear & tear on the system (pump head; high pressures) |
Roller pump1. Inexpensive 2. Predictable pump flow based on pump speed 3. Can pump large quantities of air 4. Potential to overpressurise circuit if inadvertently clamp/obstruct 5. Failure of pump rare during prolonged extracorporeal use a. Note that maintenance is due on a pump after a prolonged trial of ECMO - a 7 day run = 144 average CABG cases 6. Cumulative wear on the segments of plastic that lies under the roller head is the most frequent cause of failure a. Routinely feed pump head tubing along to distribute wear b. Mount 2 pumps in parallel c. Some prefer roller for ECMO 7. Simpler design-less moving parts to malfunction 8. Better-quicker response to servocontrol |