01 Apr NIPP Ventilator

Non Invasive Positive Pressure Ventilator – 3D Printable Concept

Advent of global pandemic of Covid-19 had led several deaths across globe and doctors and nurses have a hard time coping up with the shortage of various medical supplies. Some of the most essential needs are Sanitizer, Gloves, Masks and Ventilators. Most hospitals across globe have a pressing need of the quick workable model for the ventilators.

We did a quick analysis of the hospital ventilators and came to a conclusion that it’s a critical to life device. Given the short span of time we were unable to figure out some of the critical features associated with the ventilators.

Our primary endeavor is to quickly work out a 3D printable device that will mimic the non invasive positive pressure ventilators. Readers must keep in mind that the present model fulfills some of the critical needs such as minute ventilation and oxygen therapy etc.

The ventilator is suppose to provide the necessary amount of oxygen for every breath. This oxygen can be pure O₂ for FiO₂ compliance and is called as “Fraction of inspired oxygen” for those who need more pure oxygen. Respiratory Rate (RR) is breath/minute, tidal volume (TV) is total volume of air moved in & out of lungs in a minute and is around 6-10ml/kg of the patient weight or the average at 500ml for each breath. Minute Ventilation (MV) is the amount of ventilation received in a minute (MV=RRxTV). The intake air pressure is within 5 cmH ₂ O (MIN) to 30 cmH ₂ O (MAX) and provision for the CO₂ removal for the some patient who have poor exhalation capacity. The overall arrangement and values are quite complex and please refer to https://www.ncbi.nlm.nih.gov/ for details.

This NIPP Ventilator is a 3D printable version and needs Arduino link to make it work in the most urgent need.

Working:

It’s basic principle is the reciprocating compressor with one way valve and Arduino PCP to control the motor speed/actuation to meet the FiO₂ Compliance via supplemental oxygen supply, Pressure and RR requirement with effective CO₂ removal.

As evident from the above picture that FiO₂ compliance and CO₂ removal is achieved along with RR and Pressure requirement. Just a note that this was done in the shortest possible time and pressure value may deviate due to absence CFD support.

Gear mechanism with two sized cylinder has an advantage over link mechanism in effective CO₂ removal and managing the inspiration/expiration pressure control however the design is little complex and gear sizing and gear meshing becomes tricky.

Given the simplicity in the mechanism with 3D printed parts and reliability in emergency time one can take these parts to print and assemble quickly to address the need.