SAVe II+ OPERATOR’S MANUAL > Page 52
Appendix D: Principles of Operation
The SAVe II+ is a completely self-contained, small, lightweight, rechargeable battery
powered device intended to provide controlled, positive pressure ventilation to a
patient. It is a time-cycled pressure-limited volume-targeted ventilator. The SAVe II+
will monitor the patient’s airway pressure and provide alarms for key events such as
but not limited to: disconnect, high pressure and device malfunction. The SAVe II+
uses a single-patient-use breathing circuit to connect to the device on one end and to
the patient interface on the other end. The breathing circuit on the patient end uses an
industry standard 15/22 mm connector to facilitate connection with an appropriate
breathing mask, airway, or tracheal (breathing) tube. On the ventilator end, the
breathing circuit has 3 connections: 1) The main tube to deliver air to the patient; 2)
The pressure line to monitor the patient pressure; and 3) the control line to activate the
control valve which opens and closes the exhaust port.
The SAVe II+ user interface is intended to provide as few user interactions as possible.
Quick selection buttons are organized in an arc-shaped graphic which allows quick
selection of appropriate default ventilator settings based on the patient’s height,
ranging from 4’3” to 6’3”. After selecting the patient’s height, pressing the CONFIRM
button will start the device in “Ventilation” mode. This “Adult Presets” section is
intended to make initial setup minimal. When desired a User may adjust key variables,
such as: RESPIRATORY RATE (RR) [Breaths Per Minute], TIDAL VOLUME (TV)
[Milliliters/Breath], POSITIVE END-EXPIRATORY PRESSURE (PEEP) [CMH2O], and
PEAK INSPIRATORY PRESSURE (PIP) limit [CMH
2
O] in the “User Defined” section
of the user interface. In certain situations (like during CPR), the user may desire to
control when a breath is delivered. For these situations, the user may switch from
“Ventilation” mode to MANUAL / CPR mode by setting the RR to zero (0). In MANUAL
/CPR mode, the ventilator will only deliver a breath to the patient after the user has
pressed the MANUAL TRIGGER button.
The flow rate of the delivered breath is determined by the combination of the selected
TV and RR as well as the I:E ratio. The I:E ratio is fixed at 1:2. TV and RR combinations
that require flow rates greater than the pumps ability to deliver the breaths and still
maintain an I:E ratio of 1:2 are not permitted. For patient safety purposes, the target
TV may not be reached if the patient airway pressure reaches the PEAK
INSPIRATORY PRESSURE (PIP) Limit.
When the PIP Limit is reached, the SAVe II+ will automatically cut the pump off and
move into the exhalation phase of the breathing cycle to prevent harm to the patient.
When desired, expiration pressure is also regulated to provide a slightly positive end
expiratory pressure (PEEP). The SAVe II+ will also provide a breath if the patient
spontaneously inspires (Spontaneous Breath). The device detects patient inspiratory
effort by monitoring airway pressure. The device will respond in less than 250 ms to a
pressure drop greater than 2 cmH
2
O below set PEEP.
In MANUAL / CPR mode, the user has control over when a breath is delivered to the
patient. As this mode will commonly be used during CPR, a Heart icon on the User
Interface will flash at a rate of 100/minute, which is the presently recommended
compression rate by the American Heart Association for CPR. In this mode the PIP
Limit will automatically be set to 20 cmH
2
O (as opposed to 30 cmH
2
O in “Ventilation”