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MV part 1 - Coggle Diagram
MV part 1
Mv settings
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Sigh Volume: Deep breath (1.5–2× VT, 4–5/hour).
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Modes of Mv
CM/ CMV
CM/CMV: Full ventilation by machine.
Preset: VT, RR, and FiO₂ by physician.
Ventilator initiates and controls all breaths.
Patient cannot breathe spontaneously.
Used when apneic or on muscle relaxants
A/c
A/C Mode: Full ventilatory support.
Preset: VT and RR by ventilator.
Patient can trigger extra breaths; ventilator delivers full VT each time.
Total RR = set rate + patient-initiated breaths.
Used when patient is weak, newly intubated, or recovering from anesthesia.
IMV
IMV: Ventilator delivers preset breaths (VT + FiO₂ + RR).
Patient can breathe spontaneously between mandatory breaths.
Spontaneous breaths not assisted by ventilator.
Mandatory breaths not synchronized with patient effort.
May cause patient–ventilator dyssynchrony → “fighting the ventilator,” distress, ↑ work of breathing.
SIMV
Same as IMV but synchronized with patient’s effort.
Prevents patient–ventilator fighting.
Preset rate and tidal volume.
Patient can breathe spontaneously above set rate.
Each trigger → either mandatory or spontaneous breath.
Spontaneous breath tidal volume depends on patient’s effort.
Pressure support can be added to reduce work of breathing (WOB).
Commonly used for weaning from mechanical ventilation.
CPAP
CPAP = Continuous positive pressure maintained throughout breathing cycle.
Patient breathes spontaneously (no mandatory breaths).
Keeps alveoli open → increases FRC (functional residual capacity).
Similar to PEEP in mechanism.
Used for refractory hypoxemia (unresponsive to O₂ therapy).
Improves oxygenation and prevents alveolar collapse.
PSV
PSV = Patient breathes spontaneously with positive pressure assist on inspiration.
Ventilator gives pressure boost to each spontaneous breath.
Reduces airway resistance and work of breathing (WOB).
Can be combined with SIMV or used alone.
Indicated for small spontaneous VT or difficult weaning.
Mainly used for weaning from MV.
Typical pressure: 6–12 cm H₂O.
BIPAP
Pressure-controlled ventilation with two pressure levels:
P high (IPAP) → inspiratory pressure.
P low (EPAP or PEEP/CPAP) → expiratory pressure.
The ventilator cycles between these two pressure levels.
Time at P high = inspiratory time (preset).
Expiratory time = calculated from respiratory rate.
Improves oxygenation and ventilation while allowing spontaneous breathing at both pressure levels.
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indication of Mv
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Maintains/improves ventilation, oxygenation, and comfort.
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Types of breaths
Mandatory breath: Triggered, limited, and cycled by ventilator; patient passive.
Assisted breath: Triggered by patient, limited & cycled by ventilator; shared work.
Spontaneous breath: Triggered, limited, and cycled by patient; full patient effort.