ECMO-/ECLS

the size of these patient’s triggered breaths depend on the patient effort and they
are not support by the ventilator at all.
Assist controlled (AC): The ventilator delivers the set amount of breaths and will
also deliver extra breaths (with the same level of support as the mandatory ones) if
it detects a patient breathing effort above the set rate.
Synchronized intermittent mandatory ventilation (SIMV) +/- pressure support
(PS): It is similar to IMV but the ventilator synchronizes the mandatory breaths with
the patient effort. For example, if the RR is set at 12 breath/min, the ventilator
would wait up to 5 seconds in order to detect a patient effort; if an effort is detected
at any time during that period, a fully supported breath is delivered in ‘synchrony”
with that effort. If not effort is detected, a fully supported breath is delivered
regardless of the lack of patient effort. Again similar to IMV, the patient is able to
breath above the set RR. The level of ventilator support during these spontaneous
breaths could be set from none to a level (by choosing the SIMV/PS mode) that
equals the support received during the mandatory breaths.
Continues positive airway pressure /Pressure support (CPAP/PS): In this
mode of ventilation, a constant airway pressure is set without a set RR (therefor no
mandatory breaths are delivered to the patient). All breaths have to be triggered by
the patient. The clinician can choose the level of support of these breaths from
none to a very significant level depending on a set PS. Most ventilators have a
backup RR option in case the patient is or becomes apneic while on this mode.
Triggers:
On modern ventilators ventilator circuits have constant gas flow going from the
inspiratory limb of the circuit to the expiratory one; patient efforts are detected by