Podcast
Questions and Answers
What is minute ventilation (VE)?
What is minute ventilation (VE)?
The total volume of gas entering (or leaving) the lung per minute.
What is the formula for minute ventilation?
What is the formula for minute ventilation?
(Tv) x respiratory rate
What is considered normal minute ventilation?
What is considered normal minute ventilation?
5 to 8 L per min
What is the ideal body weight (IBW) formula for men?
What is the ideal body weight (IBW) formula for men?
What is the ideal body weight (IBW) formula for women?
What is the ideal body weight (IBW) formula for women?
Adult lungs do NOT get larger as he or she gains weight.
Adult lungs do NOT get larger as he or she gains weight.
Initial VT of _____ mL/kg IBW and a rate of 10 to 20 breaths/min is generally accepted.
Initial VT of _____ mL/kg IBW and a rate of 10 to 20 breaths/min is generally accepted.
What is the IBW in kg for a female patient who is 5 feet 6 inches?
What is the IBW in kg for a female patient who is 5 feet 6 inches?
What is the IBW in kg for a male patient who is 5 feet 6 inches?
What is the IBW in kg for a male patient who is 5 feet 6 inches?
An initial VT of 6 to 8 mL/kg IBW with a rate of _____ breaths/min is acceptable.
An initial VT of 6 to 8 mL/kg IBW with a rate of _____ breaths/min is acceptable.
In patients with chronic or acute restrictive disease, an initial VT of _____ mL/kg IBW with a rate of 15 to 25 breaths/min is indicated.
In patients with chronic or acute restrictive disease, an initial VT of _____ mL/kg IBW with a rate of 15 to 25 breaths/min is indicated.
As suggested in restrictive disease, lower VT and _____ rates are used.
As suggested in restrictive disease, lower VT and _____ rates are used.
What are the IBW, Vt, and Ve for a male patient who is 6 feet tall, using a RR of 10?
What are the IBW, Vt, and Ve for a male patient who is 6 feet tall, using a RR of 10?
When setting tidal volume and rate, what is the goal?
When setting tidal volume and rate, what is the goal?
Maintaining plateau pressure lower than _____ cm H2O is optimal.
Maintaining plateau pressure lower than _____ cm H2O is optimal.
PIP - PEEP less than _____ cm H2O is optimal.
PIP - PEEP less than _____ cm H2O is optimal.
What does tubing compliance/system compressibility reflect?
What does tubing compliance/system compressibility reflect?
What does the formula CT = ΔV/ΔP in mL/cm H2O represent?
What does the formula CT = ΔV/ΔP in mL/cm H2O represent?
What is mechanical dead space (VDmech)?
What is mechanical dead space (VDmech)?
An example of VDmech is a 6-inch piece of corrugated tubing between the Y-connector and the tracheostomy tube connector; Y-connector between the ventilator and the patient may add about _____ mL.
An example of VDmech is a 6-inch piece of corrugated tubing between the Y-connector and the tracheostomy tube connector; Y-connector between the ventilator and the patient may add about _____ mL.
What is the equation for total cycle time and flow?
What is the equation for total cycle time and flow?
If the rate is set at 10 breaths/min, the TCT is _____ seconds.
If the rate is set at 10 breaths/min, the TCT is _____ seconds.
If the TI is set at 2 seconds when the rate is 10 bpm, then the expiratory time is _____ seconds and the ratio is ____.
If the TI is set at 2 seconds when the rate is 10 bpm, then the expiratory time is _____ seconds and the ratio is ____.
TI can be determined if VT and flow are known and the flow pattern is a constant or _____ waveform.
TI can be determined if VT and flow are known and the flow pattern is a constant or _____ waveform.
What is the formula to determine VT when TI and flow are known and flow is constant?
What is the formula to determine VT when TI and flow are known and flow is constant?
_____ equals VT/TI.
_____ equals VT/TI.
For a 63-year-old female patient who is 5'8'' with CO2 of 83 mm Hg, what is her IBW in kg and what should be her Vt using 6?
For a 63-year-old female patient who is 5'8'' with CO2 of 83 mm Hg, what is her IBW in kg and what should be her Vt using 6?
With a flow of 0.5 L/s or 500 ml/s, what is the Ti for a 63-year-old female patient who is 5'8'' with CO2 of 83 mm Hg?
With a flow of 0.5 L/s or 500 ml/s, what is the Ti for a 63-year-old female patient who is 5'8'' with CO2 of 83 mm Hg?
What is the TCT for 18 breaths per minute?
What is the TCT for 18 breaths per minute?
What is the expiratory time (Te) for a TCT of 3.33 and Ti 0.8 sec, and what is the Ti/Te ratio?
What is the expiratory time (Te) for a TCT of 3.33 and Ti 0.8 sec, and what is the Ti/Te ratio?
How fast is inspired gas delivered to a patient?
How fast is inspired gas delivered to a patient?
A good start for flow on inspiration is _____ second with a range of 0.8-1.2 seconds.
A good start for flow on inspiration is _____ second with a range of 0.8-1.2 seconds.
Shorter I-times result in _____ peak pressures.
Shorter I-times result in _____ peak pressures.
Slower flows may _____ peak pressures, improve gas distribution, and increase mean airway pressures and can be useful during ARDS.
Slower flows may _____ peak pressures, improve gas distribution, and increase mean airway pressures and can be useful during ARDS.
What does the most appropriate flow pattern depend on?
What does the most appropriate flow pattern depend on?
In a _____ flow, glow is greatest at start in inspiration when patient demand is greatest.
In a _____ flow, glow is greatest at start in inspiration when patient demand is greatest.
Constant flow patterns are called ____. Provides the shortest Ti of all available flow patterns with an equivalent peak flow rate setting.
Constant flow patterns are called ____. Provides the shortest Ti of all available flow patterns with an equivalent peak flow rate setting.
Flow produces a tapered flow at the end of the inspiratory phase, resulting in a _____ pattern.
Flow produces a tapered flow at the end of the inspiratory phase, resulting in a _____ pattern.
____ ramp provides a progressive increase in flow and is only available on old vents.
____ ramp provides a progressive increase in flow and is only available on old vents.
Select the effective flow patterns when ventilating patients with normal lung function:
Select the effective flow patterns when ventilating patients with normal lung function:
A descending flow pattern may be beneficial for patients with ______ and ______ by maintaining low peak pressures and high airway pressures.
A descending flow pattern may be beneficial for patients with ______ and ______ by maintaining low peak pressures and high airway pressures.
A constant (rectangular) flow pattern produces a lower airway pressure when compared to a descending flow pattern and may be useful for patients with severe ______ and ______.
A constant (rectangular) flow pattern produces a lower airway pressure when compared to a descending flow pattern and may be useful for patients with severe ______ and ______.
For patients with high Raw, a _____ pattern is more likely to deliver a set VT at a lower pressure.
For patients with high Raw, a _____ pattern is more likely to deliver a set VT at a lower pressure.
_____ is influenced by the condition of the patient's lungs and conductive airways, and the patient's changing metabolic needs.
_____ is influenced by the condition of the patient's lungs and conductive airways, and the patient's changing metabolic needs.
Inspiratory pause - A plateau pressure (Pplat) is also called _________
Inspiratory pause - A plateau pressure (Pplat) is also called _________
What maneuver is performed by preventing the expiratory valve from opening at the end of inspiration?
What maneuver is performed by preventing the expiratory valve from opening at the end of inspiration?
A patient can be actively breathing so a stable pressure reading can be obtained, which is why we perform the pause at the end of inspiration.
A patient can be actively breathing so a stable pressure reading can be obtained, which is why we perform the pause at the end of inspiration.
PEEP of 3-5 maintains ____.
PEEP of 3-5 maintains ____.
Low level of PEEP is good for _____ who would normally pursed-lip breathe.
Low level of PEEP is good for _____ who would normally pursed-lip breathe.
Determining _____ in pressure ventilation involves measuring Pplat and baseline pressure after initial volume-targeted breath.
Determining _____ in pressure ventilation involves measuring Pplat and baseline pressure after initial volume-targeted breath.
Initial settings for PSV done during _____: Set level equal to PIP - Pplat.
Initial settings for PSV done during _____: Set level equal to PIP - Pplat.
What is the goal for PSV?
What is the goal for PSV?
Use backup ventilation mode if PSV is being used by itself.
Use backup ventilation mode if PSV is being used by itself.
IPAP of _____ cm H2O should be increased in increments of 3 to 5 until a rate of 25 breaths/min or lower is achieved.
IPAP of _____ cm H2O should be increased in increments of 3 to 5 until a rate of 25 breaths/min or lower is achieved.
EPAP (PEEP) is started at _____ cm H2O and increased in increments of 3 to 5.
EPAP (PEEP) is started at _____ cm H2O and increased in increments of 3 to 5.
Adjust IPAP and EPAP (PEEP) until Vt of _____ mL/kg or more is achieved.
Adjust IPAP and EPAP (PEEP) until Vt of _____ mL/kg or more is achieved.
Hypoxemic respiratory failure will need a higher _____ of at least 5 cm H2O.
Hypoxemic respiratory failure will need a higher _____ of at least 5 cm H2O.
In PVRC, remember the vent progressively adjusts the _____ level until the set Vt is achieved.
In PVRC, remember the vent progressively adjusts the _____ level until the set Vt is achieved.
PVRC refers to what type of mode?
PVRC refers to what type of mode?
In PVRC, cough or bucking the vent won't let pressure exceed limit.
In PVRC, cough or bucking the vent won't let pressure exceed limit.
Volume support is what type of breathing mode?
Volume support is what type of breathing mode?
In volume support mode, the set Vt is the minimum Vt, but the patient can obtain a higher Vt if they want.
In volume support mode, the set Vt is the minimum Vt, but the patient can obtain a higher Vt if they want.
Study Notes
Minute Ventilation (VE) and Tidal Volume (Tv)
- Minute ventilation (VE) represents total gas exchanged in the lungs per minute.
- Formula for minute ventilation: VE = Tv x respiratory rate.
- Normal minute ventilation ranges from 5 to 8 L/min.
Ideal Body Weight (IBW)
- IBW for men: 106 + 6(H − 60).
- IBW for women: 105 + 5(H − 60).
- Example calculations:
- Female patient at 5'6" has an IBW of 61.4 kg.
- Male patient at 5'6" has an IBW of 64.5 kg.
Ventilation Settings
- Initial tidal volume (VT) recommended: 6 to 8 mL/kg of IBW, respiratory rate of 10 to 20 breaths/min.
- For patients with airway obstruction, use initial VT of 6 to 8 mL/kg with a rate of 8 breaths/min.
- In chronic or acute restrictive diseases, aim for an initial VT of 4 mL/kg with a rate of 15 to 25 breaths/min.
Pressure Goals
- Maintain plateau pressure (Pplat) below 30 cm H2O.
- Optimal peak inspiratory pressure (PIP) minus PEEP should be under 15 cm H2O.
Mechanical Dead Space
- Mechanical dead space (VDmech) is the volume of gas rebreathed due to ventilator circuit design.
- Example of VDmech: 6-inch corrugated tubing adds approximately 75 mL.
Total Cycle Time and Flow
- Total cycle time (TCT) equation: TCT = TI + TE; inverse for flow rate: 60 seconds/TCT = f.
- For a rate of 10 breaths/min, the TCT equals 6 seconds.
Flow Patterns
- Flow influences inspiratory time (TI) and tidal volume (VT).
- Constant (square) flow patterns are most familiar and provide shortest TI.
- Descending flow patterns are beneficial for hypoxemia and low lung compliance, delivering VT at lower pressures.
- Constant flow patterns are suitable for patients with hypotension or cardiac instability.
Pressure Ventilation Concepts
- Pplat is obtained by holding the inspiratory valve closed at the end of inspiration.
- PEEP levels of 3-5 are essential to maintain functional residual capacity (FRC).
- Low levels of PEEP are advantageous for patients with COPD.
Weaning and Pressure Support Ventilation (PSV)
- Initial PSV settings: level set equal to PIP - Pplat.
- Goals for PSV: increase VT to 4-8 mL/kg, lower respiratory rate to under 30 breaths/min, and reduce work of breathing (WOB).
- Backup ventilation is recommended during the use of PSV.
Settings for IPAP and EPAP
- Start IPAP at 5-10 cm H2O, increasing incrementally until achieving a rate of 25 breaths/min or lower.
- EPAP (PEEP) begins at 2-5 cm H2O with similar increments in management.
Volume Support Mode
- In volume support, the set VT represents the minimum, allowing patients to achieve higher VT.
- This mode operates under spontaneous breathing conditions with preset sensitivity and pressure limits.
General Principles
- Minute ventilation is affected by lung conditions and metabolic needs.
- Use of high PEEP is indicated for hypoxemic respiratory failure.
- The ventilator adjusts pressure progressively to achieve the set VT.
Studying That Suits You
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Description
Test your knowledge with these flashcards on Mechanical Ventilation from Chapter 6. Each card covers important concepts such as minute ventilation, tidal volume, and ideal body weight formulas. Perfect for students and professionals in respiratory care.
