Volume-targeted Modes
Pressure-targeted Modes
Adaptive Support Ventilation (ASV)
ASV provides intelligent ventilation mode that continuously adjusts respiratory rate, tidal volume, and inspiratory time depending on the patient’s lung mechanics and effort. This is similar to “Auto-Flow” or other like settings on different brands of ventilators. Currently only available on the Hamilton-T1.
Continuous Positive Airway Pressure (CPAP)
CPAP Is a type of positive airway pressure, where the air flow is introduced into the airways to maintain a continuous pressure to constantly stent the airways open, in people who are breathing spontaneously.1 CPAP provides constant pressure above that of the atmospheric pressure. Delivered via the upper respiratory tract.
Pressure Regulated Volume Control (PRVC) Ventilation
PRVC ventilation is designed for invasive mechanical ventilation and combines volume and pressure strategies. PRVC delivers a pressure-controlled and tidal volume (VT)–targeted breath using a decelerating flow waveform pattern that allows unrestricted spontaneous breathing with or without pressure support (PS). 2 (may be Impact 731 only). ***
BL (bilevel)
The BL ventilator provides two pressure settings to assist patients breathing spontaneously: a higher inhalation pressure (IPAP) and a lower exhalation pressure (EPAP).NOTE: This feature is only available on the Zoll. ***
***See Acute Respiratory Failure CPG for more detail on advanced ventilator modes/settings.
VENTILATOR ADJUSTABLE SETTINGS
Tidal volume (VT )
The volume of gas, exchanged during a breath and commonly expressed in milliliters. VT is generally set between 4-8ml/kg IBW, to prevent lung over distension and barotrauma.4-8
Ideal IBW
The weight at which tidal volume is calculated against instead of using actual weight. This enables patients to be ventilated in a lung-protective strategy. A quick reference chart can be found in Appendix C. IBW can be calculated manually as follows:
Minute Ventilation (VE)
The average volume of gas entering, or leaving, the lungs per minute, commonly expressed in liters per minute. Also called minute volume. Minute ventilation is the product of VT and RR (respiratory rate). Normal VE is 5 – 10 L/min. 4-8
I:E Ratio
See I:E definition. I:E might need to be adjusted for physiology that requires extended exhalation time. 4-8 For example: Asthma patient may require an I:E of 1:3, 1:4, or 1:5 to allow for more exhalation time.
Flow Rate
Is the velocity at which gas is delivered to the patient, expressed in liters per minute. When the flow rate is set higher, the speed of gas delivery is faster and inspiratory time is shorter. 4-8
Peak Inspiratory Pressure (PIP)
Represents the total pressure that is required to deliver the VT and depends upon various airway resistance, lung compliance, and chest wall factors. It is expressed in centimeters of water (cm H2O).
Sensitivity or trigger sensitivity
Trigger sensitivity Is the effort, or negative pressure, required by the patient to trigger a machine breath, commonly set so that minimal effort (-1 to -2 cm H2O) triggers a breath.1,3 This is usually seen with assist modes of ventilator operation.
Pressure alarms
Pressure alarms ensure that providers are alerted to pressures that fall outside of appropriate ranges and have potential to harm the patient via barotrauma (over-pressure) or under-ventilation (circuit disconnect or under-pressure). Pressures will be determined by placing the patient on the vent for ~1-2 minutes and determining intrinsic peak inspiratory pressure. (Labeled as PEAK on 754 Ventilator (top right); Labeled as peak on Hamilton T1 ventilator (top left); Labeled as PIP on ZOLL EMV+ (731) (right center). Standard alarm settings should be: Need to measure a peak pressure 5 min after setting initial settings.