|The University of Kansas |
Respiratory Care Education
|The control panel of the Bear 1000 has one knob (Set) that adjusts the settings for all the controls.|
|Each control for tidal volume, rate, peak flow, etc has a touch pad and a LED display. To set tidal volume, for example, the volume pad is pressed which illuminates an indicator light. The Set knob is then used to adjust the tidal volume which is read in the LED display.|
|All the alarms are also set with one knob, the Alarm Set. Each alarm also has a touch pad and a LED display.|
|To set an alarm press the touch pad which lights the indicator. Pads below the LED readout have arrows to indicate whether the upper alarm limit or the lower alarm limit is being set. The Alarm Set knob adjusts both and the value is read in the LED display.|
There are several features on the Bear 1000 that allow the operator to manipulate the pressure or flow waveforms: Pressure Augment, Flow Augmentation, Volume Augmentation, and Pressure Slope.
|When Pressure Augment is active in pressure control mode, the patient receives pressure-controlled breaths as long as the preset tidal volume is achieved. If the flow during a breath falls to the Peak Flow setting and the tidal volume has not yet be delivered, volume-controlled ventilation takes over at the set Peak Flow until the volume is delivered. When volume-controlled ventilation takes over, the airway pressure will rise above the pressure control setting.|
|As llustrated above in the first waveform, the preset tidal volume has been delivered by the point in time indicated by the arrow, and the breath is essentially pressure controlled. Inspiration ends when the flow falls to 30% of the initial peak value since Pressure Augment is active. If Pressure Augment is not active, pressure controlled breaths are time cycled. In the second waveform, the flow has fallen to the peak flow level and the tidal volume has not been achieved. Note how the pressure increases above the pressure control level as flow is provided at the Peak Flow setting.|
|In Flow Augmentation during volume-controlled breaths, the patient receives additional flow as long as the patient's inspiratory effort keeps the airway pressure below baseline. This signals the Flow Control Valve to deliver additional flow. When the inspiratory demand is met, the flow returns to the peak flow level and the set tidal volume is delivered.|
|Volume Augmentation is similar to Flow Augmentation. The only difference is that in Volume Augmentation, the patient continues to demand more flow after the set tidal volume has been delivered. Flow will be delivered as long as the patient's inspiratory effort keeps the airway pressure below baseline.|
The Pressure Slope can be set for all pressure breaths to dampen the initial blast of flow. It adjusts the time required to reach the pressure control or support level. Pressure Slope slows the opening of the Flow Control Valve. The slower the flow, the longer it takes for the pressure to build. The Pressure Slope control has adult and pediatric settings.
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RC Ed WebMaster