Rate (f): Respiratory rate. 12-20 bpm.
I-time: Time (in seconds) the breath is delivered over. 0.8 to 1.2 seconds.
I:E ratio: Ratio of inspiratory time to expiratory time. A higher I:E ratio results in less inspiratory time and more expiratory time in the same length of the breath cycle. Example: rate of 12, I-time of 1.0 second would have an I:E ratio of 1:4 (1 second inspiration to 4 seconds expiration). Patients with restrictive lung disease may need longer expiratory time.
Volume: Tidal volume to be delivered. 6-8 mL/kg IBW (4-6 mL/kg is lung protective).
Pressure Control: Pressure to be delivered for each breath.
Pressure Support: Used with SIMV. Set amount of pressure to supplement patient initiated breaths. Used to overcome dead air space in the ETT and vent circuit.
PEEP (positive end exploratory pressure): Pressure within the lungs at the end of expiration. Keeps the alveoli open. Physiologic PEEP is 3-5 cmH2O. 5 to 20 cmH2O.
Sensitivity: Amount of effort needed for the patient to trigger a breath. Defaults to 2 lpm and can be set to P for a pressure trigger or 1 through 4 lpm for a flow trigger (1 being the most sensitive). Excessive road vibration may trigger additional breaths. In this case, sensitivity value may need to be increased. A flow trigger responds when a patient’s inspiratory flow reaches a preset level (ex. 2 lpm of flow generated with inhalation). A pressure trigger responds to a change of 3 cmH2O (default) of pressure below the set PEEP.
FiO2 (fraction of inspired oxygen): Percentage of oxygen being delivered. Room air is 21%. Can go up to 100% oxygen. Titrate for SpO2/PaO2 goals. May need to be set to 100% for smoke inhalation/burns until CO poisoning is ruled out.