Ventilators Flashcards
What do ventilators provide?
Intermittent positive pressure ventilation (IPPV)
What are the two forms of generators?
Constant flow and constant pressure
What generator is good for patients with lung disease?
Constant pressure
Which generator CANNOT compensate for leaks?
Constant flow
(because volume rate remains unchanged)
What happens in modern ventilators once the pressure limit is reached?
The flow decelerates 💨👇
This maintains peak pressure at limit for the rest of the breath
What pressure limit is appropriate for adults?
30-35cm H2O
What are the four types of cycling?
Volume 📦, pressure 💪, time ⌚, flow 💨
What is predetermined in volume cycling?
Tidal volume
What is positive end expiratory pressure?
Positive pressure remaining in the airway at the end of exhalation
What does PEEP do to the alveoli?
Keeps them expanded 🎈
Increases gas transfer 👆
Reduces risk of pulmonary oedema
How can a pulmonary oedema be reduced through PEEP?
Water in the interstitial space is “pushed” back into lung tissue
What does PEEP do to venous return, and therefore cardiac output?
Reduces it 👇
What is the I:E ratio?
The ratio of the inspiratory portion compared to the expiratory portion of the breathing cycle
What is the usual I:E ratio?
1:2
What is the usual I:E ratio in young children/neonates?
1:1
What does an inverse I:E ratio (2:1) allow for?
A shorter expiratory increases the intra-thoracic volume -> recruiting alveoli in a manner similar to PEEP
What do high-pressure alarms detect?
Coughing and obstruction
What do low-pressure alarms detect?
Disconnection or a large leak
What is the typical pressure of PEEP?
5-15cmH2O
What pressure gives risk of barotrauma?
Above 40cmH2O
5 complications of IPPV
System disconnection/obstruction
Pneumothorax
Decreased secretion clearance
Infection
Ventilation abnormalities
