Ventilator modes

Here are flashcard-style notes based on the two presentations: “W25 Ventilation Modes I” and “W25 Ventilation Modes 2.” I’ve organized them by key topic to help you study efficiently.

🔷 Ventilation Mode Basics

Q: What are the 3 breath types? A: Mandatory, Assisted, Spontaneous

Q: What are the 3 control variables in mechanical ventilation? A: Volume, Pressure, Time

Q: What are the main breath sequences in mode classification? A: CMV (Controlled), IMV/SIMV (Intermittent), CSV (Spontaneous)

🔷 Volume Control Ventilation (VCV)

Q: What is the control variable in VCV? A: Volume (flow and volume are fixed)

Q: How does pressure behave in VCV? A: Varies depending on compliance and resistance

Q: Advantages of VCV? A:

  • Guaranteed VT

  • Good ABG control

  • Synchronizes with patient if sensitivity is set

Q: Disadvantages of VCV? A:

  • Risk of high pressures → barotrauma

  • Fixed flow may not meet patient demand

  • Risk of respiratory alkalosis or auto-PEEP

Q: What settings are entered in VC? A:

  • Rate

  • VT

  • Flow

  • PEEP

  • FiO2

  • Sensitivity

  • Optional: Inspiratory pause

Q: How is TI calculated? A: TI = VT / Flow

🔷 Pressure Control Ventilation (PCV)

Q: What is the control variable in PCV? A: Pressure

Q: How does VT behave in PCV? A: VT varies depending on compliance (C) and resistance (R)

Q: What waveform is seen with PCV? A: Square pressure waveform

Q: Advantages of PCV? A:

  • Lower risk of barotrauma

  • Better distribution of ventilation

  • Can improve oxygenation

  • Precise control of Pplat and MAP

Q: Disadvantages of PCV? A:

  • VT is not guaranteed

  • ABG may vary

Q: What settings are entered in PC? A:

  • PC level (ΔP or PIP)

  • Rate

  • TI

  • PEEP

  • FiO2

  • Sensitivity

Q: How do you calculate ΔP and PIP? A:

  • ΔP = PIP – PEEP

  • PIP = ΔP + PEEP

Q: What factors affect VT in PC? A:

  • Lung compliance

  • Airway resistance

  • Inspiratory time

  • Patient effort

🔷 Pressure Support Ventilation (PSV)

Q: What kind of breaths are delivered in PSV? A: Patient-triggered, pressure-limited, flow-cycled breaths

Q: What is PSV typically used for? A:

  • Weaning

  • Reducing WOB

  • Patients with spontaneous drive

Q: Key settings in PSV? A:

  • PS level

  • PEEP

  • FiO2

  • Sensitivity

  • Rise Time

Q: Cycle variable in PSV? A: Flow (typically ends when flow drops to 25% of peak)

Q: Disadvantages of PSV? A:

  • No backup rate

  • Not ideal for patients without reliable drive

🔷 Volume Support (VS)

Q: What is Volume Support? A: A spontaneous mode that auto-adjusts PS level to reach a target VT

Q: Advantages of VS? A:

  • VT guaranteed over several breaths

  • Self-weaning mode

  • Adjusts support based on patient effort

Q: Disadvantages of VS? A:

  • No backup rate

  • Only available in CSV mode

  • Apnea alarms are critical

Q: Trigger, Limit, Cycle in VS? A:

  • Trigger: Patient

  • Limit: Pressure-limited, volume-targeted

  • Cycle: Flow

🔷 SIMV vs IMV vs A/C (CMV)

Q: What is SIMV? A: Synchronized Intermittent Mandatory Ventilation — allows for mandatory, assisted, and spontaneous breaths

Q: What is IMV? A: Intermittent Mandatory Ventilation — mandatory breaths occur at intervals, not synchronized

Q: What is A/C? A: Assist-Control (CMV): every breath is mandatory or assisted; all breaths receive full support

🔷 Spontaneous Modes (CSV)

Q: What is CPAP? A: Continuous Positive Airway Pressure — baseline pressure only, no added support

Q: What is PSV (in CSV)? A: Pressure Support Ventilation — adds PS to spontaneous breaths

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