- This setting refers to the number of breaths per minute that the ventilator delivers.
- 8 to 12 bpm is a typical respiratory rate
FiO2 (Fraction of inspired oxygen)
- This indicates the amount of oxygen the ventilator delivers, expressed as a percentage or a number between zero and one.
- FiO2 varies widely depending on the patient's condition; room air is 21% (0.21).
- While some patients might be adequately oxygenated with an FiO2 of less than 40% (0.40), someone with severe hypoxemia, for example, might need an initial FiO2 setting of 100%
Positive end-expiratory pressure (PEEP)
- Is the pressure that exists in the alveoli at the end of expiration.
- PEEP can be used to increase oxygenation in either AC or SIMV mode.
- The effect of PEEP on the lungs is similar to blowing up a balloon and not letting it completely deflate before blowing it up again.
- Most patients are started on 5 cm H2O of PEEP
Tidal volume (TV)
- It is the amount of air that will go (delivered) into the patient's lungs with each breath.
- This is based on the ideal body weight of the patient, most often calculated at 10 mL/kg.
- The ratio of duration of inspiration to the duration of expiration.
- The ventilator inspiratory-to-expiratory time ratio (I:E) can range from 1:1.5 to 1:2 for adults
- Importantly, patient expiratory time may be shorter or longer then the amount of time allotted.
Peak inspiratory pressure (PIP)
- Is the highest level of pressure applied to the lungs during Inhalation.
- Should be less than 35 cm of H 2O
Ventilator circuit & parts of ventilator
Main inspiratory line which connects the ventilator output to the patients airway adapter or connector
Adapter which fits the main inspiratory line to the patients airway (Y connector)
Expiratory line which carries expired gas from the patients to the exhalation valve
Expiratory valve which releases exhaled gas from the expiratory line into the room air
Are used for the humidification of inspired air.
Heat moist exchangers (HME)
Or artificial noses are used for humidification in patients with mechanical ventilation.
Bacterial filters to filter to filter gas administered to the patient and exhaled by the patient.
Pressure gauze to measure the pressures in the upper airway.
A device to measure the temperature of inspired air.
An apnea or low pressure alarms
A nebulizer line to power a micro nebulizer for delivery of aerosolized medications
High pressure limit:
Secretions in ETT/Airway or condensation in tubing
Kink in ventilator tubing
Patient biting on ETT
Patient coughing, gagging or trying to talk
Increased airway pressure from bronchospasm or pneumothorax
Ventilator tubing not connected
Displaced ET tube
High respiratory rate:
Patient anxiety or pain
Secretions in ETT/ airway
Low exhaled volume:
Vent tubing not connected
Leak in cuff or inadequate cuff seal
Occurrence of another alarm preventing full delivery of breath.