understanding of ventilators

• related: ICU intensive care unit, Pulmonology
• tags: #permanent
• source: Murray and Nadel Ch 135 Mechanical Ventilation, design features of modern mechanical ventilators

---

Ventilator things

• ATC is automatic tube compensation.: adjust pressure/flow based on ET tube diameter.
• flow vs pressure limits

Parameters of ventilation

• triggers, targets, cycles of ventilators
• static and dynamic compliance
• stress index in ventilators

Modes of ventilation

• basic modes of ventilators
• APRV ventilation
• assist control ventilations are modern CMV ventilators
• NAVA senses phrenic nerve for ventilation

Cycle Desynchrony

• premature cycling is caused by high trigger sensitivity or low inspiratory time
• delayed cycling caused by low trigger and high inspiratory time

Flow Desynchrony

• changing ventilation target from flow to pressure can help with flow starvation
• flow desynchrony can happen with air hunger

Trigger Desynchrony

• ineffective trigger asynchrony
• reverse triggering is when patient initiates 2nd breath
• double triggering is when patient initiates both breaths
• adding inspiratory hold to improve double triggering

Troubleshoot

• leaks on a ventilator

Others

• calculating driving pressure in pressure support mode
• mechanical power and VILI Resistance = Peak P - PEEP

Increase flow rate decreases resistance (may not see on pressure curve anymore)

Normal compliance = 80-100 cc/cmH2O

Resistance = (dynamic - static pressure) / flow rate

Rc = Ppeak - Ppleateau cmH2O / flow L/S

Normal = < 2 cm H2O/L/sec for no intubated patient and < 10 for intubated patient

Go up on flow rate to 60L/min to start out

Increase Ti for double trigger.

Pressure flow and volume graphics over time with pressure control ventilation at baseline, under increased resistance conditions (increased Raw), and under reduced compliance conditions (decreased Crs).

Links to this note

• ICU intensive care unit

  • understanding of ventilators

• triggers, targets, cycles of ventilators

  • related: ICU intensive care unit, understanding of ventilators

• basic modes of ventilators

  • related: understanding of ventilators

• changing ventilation target from flow to pressure can help with flow starvation

  • related: understanding of ventilators

• premature cycling is caused by high trigger sensitivity or low inspiratory time

  • related: understanding of ventilators

• stress index in ventilators

  • related: understanding of ventilators

• APRV ventilation

  • related: understanding of ventilators

• adding inspiratory hold to improve double triggering

  • related: understanding of ventilators

• assist control ventilations are modern CMV ventilators

  • related: understanding of ventilators

• calculating driving pressure in pressure support mode

  • related: understanding of ventilators

• delayed cycling caused by low trigger and high inspiratory time

  • related: understanding of ventilators

• flow vs pressure limits

  • related: understanding of ventilators

• mechanical power and VILI

  • related: understanding of ventilators

• static and dynamic compliance

  • related: understanding of ventilators

• APRV has less sedation and paralysis

  • related: understanding of ventilators

• APRV settings

  • related: understanding of ventilators