Mechanical Design

iSAVE System Design Specifications

The iSAVE utilizes a series of valves and flow regulators in parallel limbs to effectively maintain the desired volume for each patient. Here, we describe the overall design, components and safety features of the iSAVE.

iSAVE System A) Closed-loop iSAVE circuit for closed-loop (dual limb) ventilator consists of filters and flow valves connected in series on each channel. B) iSAVE with closed-circuit (dual limb) ventilator employing 2 channels connected to a test lung apparatus for demonstration. The Philips NM3 respiratory monitor is used to monitor the pressure, flow, and CO2 in each patient circuit.


System Architecture
The ventilator's main outflow and inflow channels are divided to make individual channels for each patient using T or Y connectors. Then, for each patient, the breathing circuit consists of the following: 

Inspiratory channel contains the following components in series:

  1. Filter
  2. Flow control valve
  3. One-way flow valve
  4. Sensors

Expiratory channel consists of the following components: 

  1. Filter
  2. Pressure release valve (a PEEP valve can be used for this purpose)
  3. One-way valve

The system assembly can be readily adapted to an open loop (single-limb) by simply removing the pressure release valve from the expiratory limb.

Each component serves a specific purpose:

  • Flow control valves allocate the appropriate VT to each patient.
  • Bacterial/viral filters prevent cross-contamination between individual patient circuits, and filter expired gas before release into the room through the pressure release valve (in open loop systems), thus limiting pathogen exposure to healthcare workers.
  • One-way valves prevent backflow and mitigates over-distention in cases of rapid flow change.
  • PEEP valves enable the release of excess pressure that may be caused by changes in the flow to each limb.
  • Pressure, flow sensor, and CO2 sensors enable set up, titration and monitoring. Data from the sensors can be visualized on separate patient monitors or on the main ventilator.

Instructions for assembly and use can be found here.

Video of System:

(Please note: this video has no dialogue)

List of Components:

The iSAVE system is comprised of a number of readily available medical components including one-way valves, pressure release valves, flow regulators, pathogen filters, pressure/volume sensors, capnostats, and respiratory profile monitors. A complete list of components required for the close and open loop iSAVE systems, as well as their equivalents readily available in the medical industry can be found here.