Puritan Bennett
Puritan Bennet 800 Series Ventilators
800 Series Ventilator System Operator’s Manual Addendum Rev C Tube compensation options
Addendum
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ADDENDUM 1
Tube compensation option
Introduction The Tube Compensation (TC) option for 800 Series™ Ventilators is a spontaneous breath type enhancement which assists a patient’s spontaneous breath by delivering positive pressure proportional to the inspired flow. This pressure overcomes the estimated resistance of an artificial airway. TC can support all spontaneous breaths for patients with an ideal body weight ≥ 7.0 kg (15.4 lb), and for endotracheal/tracheostomy tubes with an inside diameter (I.D.) of ≥ 4.5 mm. TC can be used within SPONT, BILEVEL or SIMV, all of which permit spontaneous breaths. With the BiLevel® option selected, TC supports spontaneous breaths at both PEEP levels. TC also protects against inadvertent entry of incompatible settings, such as small ideal body weight (IBW) paired with a large airway.
Technical description When the TC option is enabled, the patient’s respiratory muscles are not required to work as hard to draw gases into the lungs as they would with no form of pressure support. This is particularly important for patients whose respiratory systems are already functioning poorly, and would have to exert even greater muscular effort to overcome the increased resistance to flow in the artificial airway of the breathing circuit. Tube Compensation provides a programmable pressure in spontaneous breath delivery mode. This assists the patient in overcoming the flow resistance of the artificial airway. Pressure is programmed to vary in accordance with the pressure fluctuations between the two ends of the respiratory tube. The ventilator continuously calculates the pressure differential and adjusts the compensation pressure accordingly. The TC software checks the flow rate every 5 ms, using an internal lookup table which contains the flow-to-pressure relationship of the selected artificial airway, and is used to calculate the amount 4-076350-00 Rev. C (10/99)
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Tube compensation option of pressure needed to maintain carina end pressure at PEEP instead of permitting it to drop to a negative value. Based on these values, the ventilator pressure valves are continually adjusted, matching the changing tube pressure compensation requirements. The TC option also includes safety protection, safety checks, and logic checks which prevent the operator from entering incompatible settings, such as a large airway size paired with a small ideal body weight. If the type of humidifier has been changed after running SST with the TC software option, the humidifier volume can be adjusted at the same time to avoid a reduction in compensation compliance accuracy.
Setting up tube compensation Follow the steps below to select TC during normal ventilator operation. Review the instructions in Section 4 of the Operator’s Guide in the 840 Operator’s and Technical Reference Manual for additional information. 1. Touch the VENT SETUP button on the lower screen. 2. Touch the MODE button, also on the lower screen. 3. As you turn the knob, the lower screen will display SPONT, BILEVEL or SIMV. 4. Touch the SPONTANEOUS TYPE button. 5. Turn the knob again to select TC. 6. Touch the CONTINUE button. The settings applicable to the selected mode, and for TC, appear on the lower screen. 7. Touch the on-screen button for each setting you wish to change, and then turn the knob to set the desired value. Proposed changes are highlighted. Press the CLEAR key above the knob to cancel any changes you’ve just made. Be sure to select the tube type (either endotracheal or tracheostomy) and set the tube I.D. to correspond to patient settings. Refer to Table 4 to select the proper tube I.D. and IBW. The tube type and tube I.D. indicators flash if TC is a new selection. Tube compensation option
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Tube compensation option 8. When you have made the settings you want, press the ACCEPT key above the knob to apply the new settings, or the CLEAR key to cancel the last change.
Adjust tube type, tube I.D., and humidification To select new settings for the tube and humidifier without having to return to VENT SETUP, follow these steps. 1. Touch the MORE SETTINGS icon, then touch the MORE SETTINGS button. 2. Touch the on screen button of the setting you wish to change. •
Tube inside diameter
•
Tube type
•
Humidification type
A humidifier volume button appears below the selection only when you have selected NON-HEATED or HEATED EXPIRATORY TUBE as the humidifier type. The button is not visible when a Heat Moisture Exchanger (HME or “artificial nose”) is selected. Turn the knob to enter a value equal to the dry humidifier volume being used. 3. Press ACCEPT to apply the new settings, or the CLEAR key to cancel the last change.
Adjust alarm settings 1. Touch the ALARMS button to access alarm settings. Touch the alarm upper and lower limit buttons. Use the knob to set the upper and lower limits for the alarms. Turn the knob clockwise to increase the setting, and counterclockwise to decrease the setting. NOTE: There is an additional alarm setting for TC: High inspired tidal volume (VTI SPONT).
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Tube compensation option 2. Press the ACCEPT key to save proposed settings, or the CLEAR key to cancel the last change. Table 1 contains the ventilator settings to be used when the TC option is selected. Table 1: Tube Compensation settings Setting
Range, resolution, accuracy
% Support
Sets the level of TC support.
Range: 10% to 100% New patient: 100% Resolution: 5% Accuracy: n/a
Tube type
Selects endotracheal (ET) or tracheostomy (Trach) tube.
Range: Trach or ET New patient: ET Resolution: n/a Accuracy: n/a
Tube I.D.
Selects the inside diameter of the tube from a range of recommended sizes. (See Table 4 for IBW & tube I.D.) Selection includes an alarm that can be overridden.
Range: 4.5 mm to 10 mm New patient: Based on IBW Resolution: 0.5 mm Accuracy: n/a
ESENS % (Expiratory sensitivity)
Percent of the peak inspiratory flow that initiates a switch from inspiration to exhalation.
Range: 1% to 45% New patient: 10% Resolution: 1% Accuracy: n/a
Trigger type
Determines how inspirations will be activated.
Range: Pressure or flow New patient: Pressure Resolution: n/a Accuracy: n/a
Humidification volume (except when HME is selected)
Sets the dry volume of the humidifier chamber in use.
Range: 100 ml to 1000 ml New patient: 480 ml (default) Resolution: 10 ml Accuracy: n/a
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Function
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Tube compensation option
Monitored settings Table 2 lists the monitored settings associated with TC. Table 2: Monitored settings Setting Spontaneous inspired tidal volume
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Function
Range, resolution, accuracy
Displays the compliance and BTPS-compensated value for inspired tidal volume. Data updated at the beginning of the following expiratory phase.
Range: 0 ml to 6000 ml Resolution: 1 ml for 0 ml to 6000 ml Accuracy: For TI ≥ 200 ms and < 600 ms, ± (10 + 10%* 600 ms/ TI ms of reading) ml; otherwise, ± (10 + 10% of reading) ml
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Tube compensation option
Alarms Table 3 lists the alarms associated with the TC option. Details of the alarms and recommended corrective actions are given. Table 3: Alarms Base message 1PCOMP
Analysis message
Remedy message
Comments
Low
Last spont breath ≥ set 2PCIRC limit.
Medium
Last 3 spont breaths ≥ set 2PCIRC limit.
Check for leaks, tube type/I.D. setting.
High
Last 4 or more spont breaths ≥ set 2PCIRC limit.
Compensation pressure limit. Target pressure ≥ 2PCIRC limit. Target pressure will be limited to 2PCIRC setting. Possible dependent alarms: 3VTE SPONT 3VE TOT 1fTOT 1VTi SPONT
Urgency
Corrective action: Check for leaks. Check for the correct tube type. Check that the tube inside diameter corresponds to the patient IBW. (See Table 4 for IBW & tube I.D.) Check the 2CIRC setting.
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Tube compensation option Table 3: Alarms (continued) Base message ↑PVENT
Analysis message
Remedy message
Comments
Low
1 breath ≥ limit.
Medium
2 breaths ≥ limit.
Check patient circuit & ET tube.
High
3 or more breaths ≥ limit.
Inspiratory pressure > 100 cmH2O and mandatory type = TC or VC. Ventilator truncates current breath unless already in exhalation. Possible dependent alarms: 3VTE MAND 3VE TOT 1fTOT
Urgency
Corrective action: Provide alternate ventilation. Remove ventilator from use and contact service. 1VTI SPONT
Low
Last spont breath ≥ set limit.
Medium
Last 3 spont breaths ≥ set limit.
High
Last 4 or more spont breaths ≥ set limit.
Check for leaks, tube type/I.D. setting.
High inspired tidal volume. Delivered inspiratory volume ≥ inspiratory limit. Ventilator transitions to exhalation. Possible dependent alarms: 3VTE SPONT 3VE TOT 1fTOT Corrective action: Check for leaks. Check for the correct tube type. Check the VTI setting
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Tube compensation option
Tube inside diameters Table 4 lists ideal body weights and corresponding, estimated tube inside diameters. If you select an inside diameter that does not match the ideal body weight, you must touch the OK button to continue. Table 4: Tube IBW & I.D. IBW (lb)
7-10
15-22
4.5
4.5
11-13
23-29
4.5
5.0
14-16
30-35
4.5
5.5
17-18
36-40
4.5
6.0
19-22
41-49
5.0
6.0
23-24
50-53
5.0
6.0
25-27
54-60
5.5
6.5
28-31
61-68
5.5
7.0
32-35
69-77
6.0
7.0
36
78-79
6.0
7.5
37-42
80-93
6.5
7.5
43-49
94-108
6.5
8.0
50-53
109-117
7.0
8.0
54-59
118-130
7.0
8.5
60
131-132
7.0
9.0
61-69
133-152
7.5
9.0
70
153-154
7.5
9.5
71-79
155-174
8.0
9.5
80-100
175-220
8.0
10.0
101-130
221-287
8.5
10.0
131-150
288-330
9.0
10.0
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ET/Trach I.D. (mm) ET/Trach I.D. (mm) (low) (high)
IBW (kg)
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Tube compensation option
Ventilator settings/guidelines The estimation of settings to use with tube compensation is aided by an understanding of: ventilator settings, data used for determination of the compensation values, and the specified performance or accuracy of the TC function. The setting for 2PCIRC must take the estimated tube compensation into consideration. The target pressure (compensation) at the patient wye is derived from the knowledge of the approximate airway resistance of the ET or tracheostomy tube being used. The compensation, pressure in cmH2O, for available tube sizes and gas flows is shown in Figure 1 and Figure 2. The estimated compensation must be added to the value of PEEP for calculation and setting of 2PCIRC.
Specified performance Performance using the TC option is specified to be: ± 0.2 joules/liter (imposed work during inspiration at the 100 % support level). In terms of ventilation, work (joules) = flow × pressure.
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Tube compensation option
Figure 1. Target pressure - at 100 % support - at the wye for ET tube sizes: 4.5 mm to 10.0 mm Tube compensation option
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Tube compensation option
Figure 2. Target pressure - at 100 % support - at the wye for tracheostomy tube sizes: 4.5 mm to 10.0 mm 4-076350-00 Rev. C (10/99)
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Tube compensation option
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