COVID-19 Driven Ventilator Landscape Their Designs & Risks

A PatBnB & Gridlogics initiative 1
1
COVID-19 Driven
Ventilator Landscape
Their Designs & Risks
About this report
This is a FREE report generated based on Crowd-searched intelligence on
www.PatBnB.com Platform. Hundreds of Innovation Catalysts, hand-
picked & verified, have submitted these findings. This initiative is
sponsored by Gridlogics Technologies Pvt. Ltd
2020

Landscape of Rapidly Manufactured Ventilator Systems 2
A PatBnB & Gridlogics initiative 2
©Bots ‘N Brains, 2020. All rights reserved.
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A PatBnB & Gridlogics initiative | ©Bots ‘N Brains, 2020
Preface
Hospitals around the world are grappling with COVID-19. Key to this challenge is making
sure our hospitals have the equipment to treat people with respiratory problems. In this
context, ventilators are pivotal pieces of medical equipment. But there are not enough
ventilators for the projected number of people who may become ill. While engineering firms
could consider switching some manufacturing to help ramp production of the vital
equipment, state of the art ventilators will still take too long to manufacture. That’s why
we’re looking to emerging markets for Rapidly Manufactured Ventilation Systems (RMVS).
[1]
According to Global Disability Innovation Hub, a detailed list of requirements on the
application form itself, with a quick overview noted below. The RMVS must [1]:
 Be reliable. It must work continuously without failure (100% duty cycle) for blocks of
14days — 24 hours a day. If necessary, the machine may be replaced after each
block of 14 days x 24 hours a day use.
 Provide at least two settings for volume of air/air O2 mix delivered per cycle/breath.
These settings to be 450ml +/- 10ml per breath and 350ml +/- 10ml per breath.
 Provide this air/air O2 mix at a peak pressure of 350 mm H2O.
 Have the capability for patient supply pipework to remain pressurized at all times to
150mm H20.
 Have an adjustable rate of between 12 and 20 cycles/breaths per minute.
 Deliver at least 400ml of air/air 02 mix in no more than 1.5 seconds. The ability to
change the rate at which air is pushed into the patient is desirable but not essential.
 Be built from O2 safe components to avoid the risk of fire and demonstrate
avoidance of hot spots.
 Be capable of breathing for an unconscious patient who is unable to breathe for his
or herself. Ability to sense when a patient is breathing, and supports that breathing
is desirable but not essential.
 Be able to supply pure air and air O2 mix at a range of concentrations including at
least 50% and 100% Oxygen. Oxygen shortages are not expected, but the ability to
attach a Commercial Off the Shelf (COTS) portable O2 concentrator machine may be
a useful feature.
 Support connections for hospital Oxygen supplies — whether driven by piped or
cylinder infrastructure
 Be compatible with standard COTS catheter mount fittings (15mm Male 22mm
Female)
 Fail SAFE, ideally generating a clear alarm on failure. Failure modes to be alarmed
include (but are not limited to) pressure loss and O2 loss.

Abstract
This report contains specification for the Rapid Manufactured Ventilator System (RMVS). A
ventilator is a machine that provides mechanical ventilation by moving breathable air into
and out of the lungs, to deliver breaths to a patient who is physically unable to breathe, or
breathing, or breathing insufficiently.[4] But in today’s time, the demand for the machine
has overwhelmingly exceed the supply. Therefore, innovators are looking for ways to
manufacture a functional ventilator in short period of time that also meet the clinical
standards.
There have been several designs that are quite functional and very easy to manufacture
based on simply principle like Bag Valve Mask (BVM). A BVM is a most basic device that can
be useful to treat the patient in initial stages. However, it becomes dangerous for rather
more serious cases. A BVM, sometimes known by the proprietary name Ambu bag or
generically as a manual resuscitator or "self-inflating bag", is a hand-held device commonly
used to provide positive pressure ventilation to patients who are not breathing or not
breathing adequately.[6] A lot of designs were later made based on this BVM principle by
replacing mechanical function from Human effort to robotic arms.
This design however fulfills the needs at principal level but fails at functional level and thus,
clinically, it is not recommended as a replacement of a common ventilator. Therefore, there
are several other designs that are developed and are shown in the following report.
Some important terms:
To understand the mechanisms and details of a Ventilator, one must be aware of following
Jargons (matrices, parameter, definitions etc.):
 PEEP– It is a ventilation mode where “the pressure in the lungs (alveolar pressure)”
at the end of the expiratory cycle is maintained “above atmospheric pressure (the
pressure outside of the body)” in simple words, positive air pressure maintained to
prevent air sack inside lungs to collapse. Normally, at 5 to 20 mmHg pressure. [2]
 Barotrauma or Pulmonary barotrauma - Damage to the lung from rapid or excessive
pressure changes, as may occur when a patient is on a ventilator and is subjected to
high airway pressure.[3]
 Tidal volume –It is the lung volume representing the normal volume of air displaced
between normal inhalation and exhalation when extra effort is not applied.[4]

Fig. 1- Flow, pressure, and volume profiles for volume-control
ventilation over 2 breath cycles; PEEP is illustrated on the
Pressure plot
How Clinical Mechanical Ventilation works?
If we boil down how a modern ICU ventilator works, there are three important parameters
[17].
 Tidal volume (air delivered to the patient)
 Inspiratory phase start (“triggering”)
 Expiratory phase start (“cycling”)
Each of these values is firs determined by the machine and healthcare operator.
Adjustments are made in real-time to optimize the patient’s clinical status, as measured by
checking lab draws and monitoring vital signs. The patient acts as a “built-in” sensor! *17+
Tidal Volume: Volume-Control vs. Pressure-Control
Tidal volume, one can set a specific volume in milliliters or set an inspiratory pressure on the
mechanical ventilator; tidal volume is often discussed and thought about as a value based
on cc/kg of ideal body weight (see Equation 1). In Acute Respiratory Distress Syndrome
(ARDS), patients’ tidal volumes are kept between 4 to 8 cc/kg. A convenient chart (PDF)
provided by ARDSNet with values for ideal or predicted body weight and different tidal
volumes corresponding to the patient’s height can be found on the web.*17+
Equation 1. Gender-specific formulas to calculate ideal body weight (courtesy: ARDSNet):
 Male Ideal Body Weight (kg) = 50 +[0.91 (height in cm – 152.4)]
 Female Ideal Body Weight (kg) = 45.5 +[0.91 (height in cm – 152.4)]
Volume control mode is just
that: a clinician defines the
tidal volume, see Fig 1. The
machine will then try to
deliver that volume with a
uniform inspiratory flow
rate, over a specified
inspiratory time (see
discussion on cycling). This
is done regardless of how
much pressure builds up in
the lungs, referred to as
peak inspiratory pressure

Fig. 2- Flow, pressure, and volume profiles for pressure-
control ventilation over 2 breath cycles; PEEP is illustrated
on the Pressure plot
(PIP). Modern ventilators have safety features to limit max pressures, which can result in
damage to the lungs (a.k.a. barotrauma). Ventilators have the capability to perform an
“end-inspiratory hold”, for a programmable duration over which the pressure in the circuit
is recorded. This is called plateau pressure (Pplat). A volume-controlled breath cycle with
inspiratory hold is illustrated in Fig 1. [17]
Pressure control mode utilizes
pressure supplied by the
ventilator, and the patient’s lung
compliance and inspiratory time
determine the volume of gas
delivered (tidal volume), see Fig 2.
As we are actively learning more
about patients with COVID-19,
what we do know is that there is
an ARDS-like clinical picture.
Therefore, we know that in
COVID-19 patients, the lung
compliance changes with the
disease course, and thus tidal
volume will change with long-term
use of pressure control ventilation. [17]
Inspiratory phase start: time / pressure / flow triggering
Inspiratory phase can either be set to start at a regular interval by locking in a constant
respiratory rate (e.g. time triggering) or have the ventilator sense the patient’s native
inspiratory effort (with a pressure or flow sensor on the circuit), and time the start of the
inspiratory phase according to the patient’s effort. This is analogous to oxygen pulse devices
used by acrobatic plane pilots. Modern ICU ventilators can be set to trigger based on
thresholds of flow (e.g. 1–4 L/min) or pressure (e.g. -1 to -5 cm H20) to initiate breaths.
These are either inherent to a specific built-in ventilation mode (SIMV, PS, CPAP, etc;
outside the present scope), or set by the clinical operator (respiratory therapist, nurse,
CRNA, physician, etc). [17]
Here, it should be noted that there is a difference between ICU ventilators and OR
ventilators: ICU ventilators tend to be more advanced and are designed to care for patients
who may require support for days, or weeks. OR ventilators are simpler and generally used
on healthier patients for shorter periods of time (minutes to hours). [17]

Expiratory phase start: time / volume / flow / pressure cycling
The start of the expiratory phase can be determined by different variables: time, volume,
flow, and pressure. Inspiratory phase duration can be programmed and expiration starts
immediately after the time for inspiration is complete; this is called “time cycling.” In
volume control, inspiration stops after the target inspiratory volume has been delivered;
this is called “volume cycling.” When inspiratory flow can be sensed, mechanical ventilator
breath can switch from inspiration to expiration when the inspiratory flow reaches 10–25%
of peak inspiratory flow; this is called “flow cycling.” Lastly, inspiration can be cycled into
exhalation when a threshold pressure is reached. For instance, if a patient coughs and
becomes asynchronous with the ventilator, the airway pressure increases dramatically. This
can be dangerous to the patient as ventilation is not effective when the patient is “fighting
the vent.” In this state, the ventilator switches inspiration to the exhalation phase and
usually concurrently triggers the high-pressure alarm. This is called “pressure cycling.” [17]

Situation in India
 In India, there is one doctor for every 1,457 people - lower than the World Health
Organization recommended 1:1,000 ratio. [10]
 People living in rural areas are completely dependent on government hospitals and
clinics, with the doctor-patient ratio at 1:10,926. [10]
 There are 40,000 ventilators for 1.3bn people [10]
 The average ICU charges per day in Mumbai areINR 4,000. In some high-end tertiary
hospitals, the charges will go upwards of INR 20,000 per day. [11]
AiMeD said it contacted seven of its ten major manufacturers, which had confirmed that the
current production capacity of ventilators was 5,500-5,750 pieces per month. [11]
A-Z of Open Source Ventilator Designs
In the wake of Covid-19 pandemic, multiple companies, research institutes, universities,
individual innovators & makers have published their rapidly manufactured ventilator
designs. Although, intent of helping the world is really noble, healthcare professionals and
hospitals must be aware of nuts and bolts behind these rapid innovations, most of which
don’t even have FDA approval or have undergone a fair clinical trial. We asked the
community of Innovation Catalysts to take up this crowd searched challenge and received
multiple open source or IP free designs (e.g. Medtronics made its design free to manufacture
without the fear of patent infringement to help in anti Covid-19 battle). These designs and
their details are listed in the following section for better understanding.

Fig. 3– Bag Valve Mask (BVM)
[A] Bag Valve Mask (BVM)
A bag valve mask (BVM), sometimes known by the proprietary name Ambu
bag or generically as a manual resuscitator or "self-inflating bag", is a hand-held device
commonly used to provide positive pressure ventilation to patients who are not breathing
or not breathing adequately. The device is a required part of resuscitation kits for trained
professionals in out-of-hospital settings (such as ambulance crews) and is also frequently
used in hospitals as part of standard equipment found on a crash cart, in emergency rooms
or other critical care settings. [6]
Standards Component:
Mask -The BVM consists of a flexible air chamber (the "bag", roughly a foot in length),
attached to a face mask via a shutter valve. When the face mask is properly applied and the
"bag" is squeezed, the device forces air
through into the patient's lungs; when the
bag is released, it self-inflates from its other
end, drawing in either ambient air or a low
pressure oxygen flow supplied by a regulated
cylinder, while also allowing the patient's
lungs to deflate to the ambient environment
(not the bag) past the one way valve. [6]
Bag and Valve - Bag and valve combinations
can also be attached to an alternative airway
adjunct, instead of to the mask. For example,
it can be attached to an endotracheal tube or
laryngeal mask airway. Small heat and moisture exchangers, or humidifying/bacterial filters,
can be used. [6]
A bag-valve mask can be used without being attached to an oxygen tank to provide "room
air" (21% oxygen) to the patient. However, manual resuscitator devices also can be
connected to a separate bag reservoir, which can be filled with pure oxygen from a
compressed oxygen source, thus increasing the amount of oxygen delivered to the patient
to nearly 100%. [6]
Bag-valve masks come in different sizes to fit infants, children, and adults. The face mask
size may be independent of the bag size; for example, a single pediatric-sized bag might be
used with different masks for multiple face sizes, or a pediatric mask might be used with an
adult bag for patients with small faces. Most types of the device are disposable and
therefore single use, while others are designed to be cleaned and reused. [6]

The routine use of cricoid pressure during BVM ventilation and endotracheal intubation was
initially standard practice but has never routinely been shown to improve patient-oriented
outcomes. Its original purpose was to occlude the esophagus and prevent gastric
regurgitation and thus aspiration. Some studies have shown it has displaced the esophagus,
rather than occluding it. Others have shown that it is incompletely occluded depending on
the amount of force applied.BVM ventilation can be aided by the use of positive end-
expiratory pressure (PEEP) valve attached and titrated from 5 to 15 cm H2O in order to
improve oxygenation prior to intubation in patients who are unable to be appropriately pre-
oxygenated with standard therapy. Do not exceed a PEEP of 20 cm H2O on a BVM as this
pressure can open the lower esophageal sphincter and cause gastric insufflation and
vomiting. [7]
Bag-mask ventilation is a very useful technique when encountering patients in respiratory
distress. The technique is commonly used by EMS, anesthesiologist, ICU nurses, respiratory
therapists, and intensivists. The technique can be life-saving and is relatively much easier
than intubation. When done well, the patient can be oxygenated until an anesthesiologist
can intubate the patient. An inter-professional approach will provide the best care for the
patient [7].

[B] Manley ventilator
This design of ventilator fulfills the following requirements. (1) The
ventilation should be designed to minimize the cardiovascular effects of intermittent
positive pressure on the anesthetized patient. (2) The machine should provide the
anesthetist with as much information as possible about the ventilation and the degree of
relaxation of the patient. This will then largely compensate for the loss of contact with the
bag. (3) The machine itselfshould be sufficiently small to stand on an anesthetic apparatus.
(4) It should operate fromthe gases supplied without ancillary sources of energy. [8]
Fig. 4 - The ventilator
Fig. 5 – Ventilator Mechanism
Fig. 6 – Gas flow during the inspiratory phase

Valve
The valve (V1) is opened and
closed by a toggle mechanism
(M) and a lever system (L) that
is acted on by the alternate
filling of the two bellows.
Valves (V2 and V3) are operated
automatically by the changes in
pressure in the tube from
bellows (Bl) to valve (V1) which
occur when valve (V1) is opened
and closed. This is achieved by
spring biased diaphragms in
small pressure chambers
attached to the valves (V2 and V3). These are set so that valve (V2) opens at a pressure of
75cm water and valve (V3) closes at a pressure of 5Ocm water. When valve (V1) is closed,
the pressure in thechambers rises to that in bellows (Bl) (100cm water) and when valve (V1)
opens, the pressure falls to that in bellows (B2) (8-30cm water). A safety blow-off valve (S)
set at 35cm water, is incorporated in the patient circuit as an added protection. [8]
Inspiratory phase
Valve 071) is closed. The fresh gas is retained in the bellows (Bl) which fills during this phase.
Valve (V2) is open and valve (V3) is closed. The weight (W) forces the gas from the bellows
into the patient’s lungs and produces inflation. The inflation pressure depends on the
position of the weight (W) on the graduated scale (P). The tidal volume depends on the
setting of the stop on the tidal volume scale (TV) and the duration of this phase depends on
the height reached by the bellows (Bl) before it causes the lever system (L) to open valve
(V1). This is set on the ‘duration of inflation’ control which alters the height of the fulcrum
(F). [8]
End of inspiratory phase
When valve (V1) opens, the pressure in the chamber falls and valve (V2) closes and valve
(V3) opens. [8]
Expiratory phase
The patient’s lungs are now open to the atmosphere and expiration takes place. The gas in
the bellows (Bl) together with the flow of fresh gases and the small volumes from the
pressure chambers now pass through valve (V1) into bellows (B2) and fill it. The duration of
Fig.7 - Gas flow during the expiratory phase
Fig. 8 - Gas flow with manual ventilation

this phase depends on the height reached by the bellows (B2) before the lever system closes
valve (V1).[8]
End of expiratory phase
When valve (Vl) closes, the pressure in the chambers rises, closing valve (V3) and opening
valve (V2), enabling inflation to take place. [8]
Manual ventilation
Taps (Tl) and (T2) are turned to the position for manual ventilation. The patient circuit is
now a Mapleson D semi-closed system (FIG. 5) allowing partial rebreathing to occur.[8]

[C] Mechanical Ventilator Milano (MVM)
Mechanical Ventilator Milano (MVM), a novel mechanical ventilator
designed for mass scale production in response to the COVID-19 pandemics, to compensate
for the dramatic shortage of such ventilators in many countries.The MVM ventilator is
inspired by the Manley ventilator, which was developed by Roger Manley in 1961, based on
“the possibility of using the pressure of the gases from the anesthetic machine as the
motive power for a simple apparatus to ventilate the lungs of the patients in the operating
theatre”. The MVM is designed to similarly meet the requirements of a ventilator as simply
as possible. The MVM will integrate advanced features designed by anesthesiologists
participating in the project who work in the medical wards in Lombardy, the region most
severely hit by the COVID-19 epidemics. [9]
The MVM features electric powered pneumatic valves rather than mechanical switches with
a stripped-down mechanical design that uses readily available, off-the-shelf components.
This enables quick progress from design to inexpensive mass production of safe, reliable
ventilators for hospitals and patients around the world. The modular design can be adapted
to swap out parts based on their availability in different regions of the world. [9]
MVM is designed to work in a pressure-controlled mode, which appears to be the correct
operation mode for the COVID-19 patients, for whom a high pressure may damage further
the lungs. MVM and can be operated in both independent ventilation (pressure-controlled
Fig.9 - Diagram of MVM

ventilation, PCV) and patient-assisted control modes (pressure-supported ventilation, PSV).
[9]
The system connects directly to a line of pressurized medical oxygen or medical air and
relies on regulation of the flow to deliver medical air, medical oxygen, or a mixture of both
to the patient at a pressure in the range suitable for treatment. Pressure regulation of the
end-expiratory cycle is achieved by discharging the expiratory flow through a valve which
sets the desired minimum positive end-expiratory pressure (PEEP). Another adjustable
pressure limiting valve is connected to the inspiratory line and ensures that the maximum
pressure delivered does not exceed the pre-set value. [9]
The MVM is currently in final prototyping to ensure compliance against clinical
requirements and has been tested on a ASL-5000 breathing simulator, which simulates a
breathing patient, at Ospedale San Gerardo in Monza, Italy. Medical certification and
regulatory approval are currently being developed in Europe (ISS), the US (FDA) and Canada
(Health Canada). The device is designed to be fully compliant with the guidelines “Rapidly
Manufactured Ventilator System” issued by the UK Medicines & Healthcare products
Regulatory Agency (MHRA), see https://tinyurl.com/v8xn9j4. [9]
Video-https://youtu.be/vZLK0OtIkXw?list=PLe-NzlyPYg5le4CexpHy0eM3yMGqxIN59
The main characteristics of the MVM are [9]:
1. Simplicity of Operation
2. Small Number of Components
3. Ease of Procurement
4. Ease of Construction
5. Cost Containment
6. Ease of Deployment
7. Customizability
8. Scalability
9. Reliability

Fig. 10 – E-Vent design by MIT
[D] E-Vent (from MIT students)
The team of MIT has worked on a design of Ventilator at low cost. Manual
ventilation is a short-term solution in a critical care environment, without any apparent
clinical evidence regarding the safety of long-term use (days-weeks). There are multiple
scenarios in which respiratory support could be needed: patients can be awake or asleep,
sedated or sedated and paralyzed, breathing spontaneously, weaning off of a vent, etc.
Furthermore, changing clinical presentations with ARDS require shifting minute ventilation
(tidal volume ✕ respiratory rate) to “lung-protective” strategies, which place patients at risk
for things like auto-PEEP. Some of these situations are simpler than others, with the
simplest being ventilating a sedated, paralyzed patient. In such a situation, at a minimum a
safe emergency ventilator could be used to free-up a conventional ventilator. [13]
Any solution should be utilized only in a healthcare setting with direct monitoring by a
clinical professional. While it cannot replace an FDA-approved ICU ventilator, in terms of
functionality, flexibility, and clinical efficacy, the MIT E-Vent is anticipated to have utility in
helping free up existing supply or in life-or-death situations when there is no other option.
[13]
Further, any low-cost
ventilator system must
take great care
regarding providing
clinicians with the ability
to closely control and
monitor tidal volume,
inspiratory pressure,
BPM, and I/E ratio, and
be able to provide
additional support in the
form of PEEP, PIP
monitoring, filtration, and
adaptation to individual patient parameters. They recognize, and would like to highlight for
anyone seeking to manufacture a low-cost emergency ventilator, that failing to properly
consider these factors can result in serious long-term injury or death. [13]
At the present time, they are producing four sets of material, which they will be releasing
and updating on this site in an open-source fashion [13]:

 Minimum safe ventilator functionality based on clinical guidance
 Reference hardware design for meeting minimum clinical requirements
 Reference control strategies and electronics designs and supporting insights
 Results from testing in animal models
Below is a cost of the components used for the manufacturing of the E-Vent which is
available for download on the official website [13]:
They are in process of continually testing and refining our prototypes to increase
robustness. The basic concept consists of two arms that gently close in sync to compress the
bag. This must be coupled with a closed loop control system. Major mechanical design
requirements include [13]:
 Be nice to your bag and its hoses – Up to 7 day ✕ 24 hour ✕ 60 minute ✕ 30 BPM ✕
2 stroke = 604,800 cycles will be needed for 7-day usage. Any design must secure the
bag and gently grasp and squeeze it from both sides to reduce the risk of material
fatigue. The grippers must be smooth and shaped to maximize air expelled without
damaging the bag. The bag must be supported with flexibility to allow motion during
operation.
 Fail-Safe operation – If the machine fails, a clinician must be able to immediately
shut down, open the device manually, remove the bag and convert to manual
bagging.
 Keep It Simple – Empower and support others to fabricate. We are focusing on the
lowest specification system and open-souring our design information for adaptation
to local supply chains.
Part Name Source Part Number Quantity Cost Total Details
Finger L (driven) McMaster 6620K25 1 343.01 343.01 Waterjet stainless steel
Finger R McMaster 6620K25 1 0 Waterjet stainless steel
1.5" 3-channel 80/20 Frame McMaster 47065T521 2 49.81 99.62
Motor driver gear AndyMark? 1 0
Bag support (front) 1 0 Lasercut acrylic
Bag support (motor side) 1 0 Lasercut acrylic
Bracket 2x2 McMaster 47065T239 5 5.25 26.25 These are not the best size; 47065T741 may be a better choice
Bracket 1x1 McMaster 47065T236 5 5.21 26.05 These are not the best size; 47065T845 may be a better choice
Screws 1/4-20 1" 30 0 May not be the best choice for 80/20
Fingertips 32 0 Lasercut acrylic; time intensive
1/4-20 4" shoulder bolts 4 0 For mounting the acrylic fingertips to the fingers
3/8" steel 3" long shafts McMaster 1263K193 2 11.29 22.58 For the fingers (plain steel is 6061K418 on McMaster)
Flange mount collar shaft McMaster 9684T28 2 46.31 92.62 For the fingers
Hex Shaft Collar McMaster 7552K5 2 21.22 42.44 For the fingers
Set screws 6-32 1/2" 6 0 For the shaft collars (+loctite)
Limit switch McMaster 7779K53 1 3.03 3.03
Mounting screw nuts McMaster 90480A005 2 0.0089 0.0178 For limit switch
Mounting screw McMaster 92949A116 2 0.0475 0.095 For limit switch
1/2" standoffs McMaster 92319A649 2 1.82 3.64 For limit switch
Screws 5-16 0
Mounting plate for motor 88895K111 1 104.31 104.31 Waterjet 6061 aluminum
Mounting plate back 88895K111 1 0 Waterjet 6061 aluminum
Ball bearing McMaster 6384K344 4 10.33 41.32 Ball bearings for fingers
Total 804.9828
Fig. 11 - A sample of Part consideration of E-Vent available on the website

Fig. 13 Components of E-Vent
 Multiple drive motor and sensing possibilities! Enable multiple configurations to
meet local supply chain capabilities.
The overall dimensions and operation are now set and any skilled mechanical designer will
be able to execute this design and adjust it to suit locally available materials and fabrication
technologies. They have ready access to water jet and laser cutters and 80/20
components;however,they are now focusing on designs that can be CNC milled, stamped,
molded, welded and bolted as per your supply chain and capability. [13]
The following are the mechanical design considerations available on the E-Vent official
website [13]:
 Big gear (bottom of arms): 16 pitches,
48 teeth, 3 in. pitch dia., 14.5° pressure angle,
0.25 in thick.
 Pinion dear (driving): 16 pitch, 30
tooth, 1.875 in. pitch dia., 14.5° pressure
angle. 0.5 in thick – this is to accommodate
axial misalignment with the arms’ gears.
 Gear ratio: 1.6 (arm/pinion)
 Based on the estimated torque (τ) of 10
N-m per arm, given in Power Calculation,
divided by the gear ratio, we arrive at 12.5 N-m applied to the pinion of diameter (d)
0.0476 m (1.875 in) with pressure angle (φ) of 14.5° the net radial load (F) on the
pinion is given by: F = 2τ/(cos(φ)d) = 2*12.5/(cos(14.5)0.0476) = 550 N.
 Also, for a handy diagram see Engineer’s Edge.
 This radial load is applied to the pinion approximately 2 cm from the face of the
gearbox which results in a bending force on the on the gearbox shaft that must be
withstood by the gearbox bearings. Consult your motor manufacturer.
 They have created a Gear Torque
and Speed Estimator Spreadsheet,
available in Downloads.
 Material choice is extremely
important – they prototyped,
based on the materials readily
available in the shop. Arm gear
and driving pinion life must be
checked for wear and fatigue, as a
function of your material selection
Fig. 12 - Arm and Gear cross-section

and width of parts. (Note: this is an oscillating load with force on the in stroke, while
the return stroke is nearly unloaded.)
 Aluminum is not recommended. They recommend steel gears, but not stainless as
this will gall/spall. Hardening the steel gears and adding lubrication will increase life.

Fig. 14 - Splitter setup
[E] Vent Splitter
Dr. Alexander Clarke, a provisional fellow in anesthesia and 3D printing
enthusiast in Australia, hosts a website called ClinicFire dedicated to aggregating medical
information. To respond to the COVID-19 outbreak, he developed a 3D printable tool meant
to divide air from a ventilator among multiple patients. [15]
Based off of a design invented by an emergency doctor named Charlene Babcock in
Michigan, Dr. Clarke’s 3D-printable device makes it possible to enable ventilation to two or
more patients. [15]
Dr. Charlene Babcock’s Design
Study Design: Four sets of standard
ventilator tubing (Hudson) wereconnected
to a single ventilator (Puritan-Bennett, 840
series) via two flow splitters (one on the
patient inflow limbof the circuit, and one
on the patient exhaust limb). Eachflow
splitter was constructed of three Briggs T-
tubeswith included connection adapters
(Hudson) (Figure 1),with the valves
removed. The Briggs T-tube is
utilizedclinically (and generally available)
for flow-by oxygen orhumidity for a patient
with an endotracheal or tracheostomy
tube, or for in-line aerosol treatments of
ventilated Patients.[16]
The T-tubes were arranged so that the two
side portsof a central T-tube were attached
to the bottom portsof the two side T-tubes via adapters that come with theT-tube. The final
configuration of the three T-tubes isseen in Figure 2 (with a trimmed section of standard
ventilation tubing at the hub for connection to the ventilator); it allowed for air flowing from
the ventilator to be split evenly to four simulated patients and for the airreturning from the
four patients to flow back into theone exhaust port on the ventilator.[16]
The ventilator tubing was run from the inflow splitterto the outflow splitter, with four test
lungs (Puritan-Bennett) in the center. The test lungs were used to simulateone patient each
on the modified ventilator circuit. Thefinal configuration was a simulation of four patients
ona single ventilator in parallel operation. [16]

To test this circuit, a time frame was arbitrarily chosenas approximately six hours. There
were two reasons forthis. First, this is a simple feasibility study, and we wouldexpect
someone to inspect the system at least once in sixhours if ever used in a real disaster.
Second, we realizethat beyond this feasibility study, animal studies areneeded, and this
could allow for observation of the function of this circuit for a longer period. Finally, in
manypotential disaster situations, by six hours additional sup-port may be available.[16]
Pressure control operation was randomly selected (viacoin toss) to precede volume control.
To approximatephysiologic parameters, the ventilator settings were dialed to a peak
pressure of 25 cm H2O, 0 cm of positiveend-expiratory pressure, and a respiratory rate of
16breaths/min. The ventilator software chose an inspiratory/expiratory ratio of 1:2
automatically. After cumulative random interval inspections, total pressure control
operation was 5 hours 33 minutes. Volume control settings of 2,000 mL tidal volume (500
mL per test lung) and a respiratory rate of 16 breaths/min were chosen to approximate
physiologic parameters. The ventilator software chose an inspiratory/expiratory ratio of 1:1
automatically. Aftercumulative random interval inspections, total volumecontrol operation
was 6 hours 11 minutes. [16]
Unlike Dr. Babcock’s design, Clarke’s makes it possible to regulate air flow resistance to
different patients, so that they aren’t all getting the same amount of oxygen. Printing two
splitters and one flow restrictor takes about six hours on a desktop machine. A four-way
splitter has been published as well, but none of his devices has been tested on people or in a
lab setting. Non-3D-printed connectors have, however, been
tested and safely used. [15]
The design concepts and computer‐aided designs were created
using Fusion 360 (Autodesk Inc, San Rafael, CA, USA). The
splitter apparatus was designed to be connected directly to a
ventilator with one device on each of the inspiratory and
expiratory breathing circuit ports. The flow restriction device
was designed to selectively reduce flow to one limb of the
parallel patient breathing circuit with the intention of allowing
the operator to adjust the tidal volume delivered to one of the
patients. This is similar in principle to a previously described
technique for single‐ventilator, two‐lung differential
ventilation. All parts were designed to be compatible with
standard 22‐mm 4 ISO 5356–1 (conical connectors for
anesthetic and respiratory equipment) breathing circuit connectors. [14]
Fig. 15- Splitter

[F] CPAP - an interim solution:
Another interim solution that companies have started working on is
converting Continuous Positive Airway Pressure or CPAP machines as breath support
devices for COVID-19 patients.
CPAP machines help people with sleep apnea breathe more easily. It is also widely used in
premature babies whose lungs are not fully developed and require respiratory support. A
CPAP machine increases the air pressure in a person's throat to prevent airway from
collapsing when inhaled. [11]
PAP therapy involves a CPAP machine, which comprises the following [12]:
 A mask that covers your nose and mouth, a mask that covers your nose only, or even
prongs that fit into your nose.
 A tube that connects the mask to the CPAP machine's motor.
 A motor that blows air into the tube.
Bengaluru-based InnAccel is working to develop a CPAP that can be used for COVID-19
patients needing breathing support.InnAccel develops and markets a portable CPAP
machine called 'Saans' – that runs on a battery where there is no power source. It can also
be hand-pumped if the battery fails. [11]

Fig. 16 – Apollo BVM Open Design
[G] Apollo BVM:
The ApolloBVM is an automated bag valve mask (BVM) device utilizing off-
the-shelf components to provide safe and continuous hospital-grade mechanical ventilation
for COVID-19 patients on an open-source basis.
The ApolloBVM is a controllable, automated add-on solution to the existing and widely
available Bag Valve Mask. The device compresses the BVM with a mechanical system that is
able to provide consistent and accurate ventilation with positive-pressure. This solution
exists within the top range of high-acuity limited-operability (HALO) ventilator solutions with
an a priori design to produce volume and pressure cycled ventilation that includes positive
end-expiratory pressure (PEEP) and enriched oxygen sources.
Controls of the ApolloBVM are familiar and clinician-designed with adult, child, and pediatric
settings. They allow for tailored ventilation, adjustable I:E ratios, and variable positive
pressure.
Set up of Ventilation Parameters
All ventilation parameters must be set by the
clinical provider caring for the patient. It is
suggested to have the patient sedated with
neuromuscular blockade for the acute phase of
respiratory support. This may be followed by
titrated sedation to a RASS score of -2. All
patients should be continuously monitored
during mechanical ventilation to include pulse
oxygenation and also ideally continuous
capnometry (end-tidal carbon dioxide -- ETCO2).

The minimum controllable parameters in order to ventilate a patient on ApolloBVM include:
Parameter Range Default
Respiratory Rate (breaths/min) 5-30 12
VT (Tidal volume in cc, set at 6-8 cc/kg of ideal
body weight)
300-650 500
I:E (Inspiratory time/Expiratory time per cycle) 1:2 to
1:4
1:3
PEEP (Positive end expiratory pressure in
cmH20)
5-20 8
PEEP Valve or Gauge: Most BVMs include a PEEP valve with an adjustable dial set for 20-40
cmH20. The purpose of this valve is to limit peak airway pressure to the number set on the
dial. Ideally, peak airway pressure should be less than 40 cmH20. It will not be possible to
measure PEEP with this valve.Select BVM models include a PEEP valve with a gauge that
ranges from 0-60 cmH20. These models allow for calibrated monitoring of PEEP during all
portions of the breath cycle.
VT should be adjusted until the desired PEEP value is reached at the end of the breath cycle
(8 cm H20 is a reasonable initial target).
With regard to ventilated COVID patients, it is quite likely that the desired PEEP will reach
the 10-15 cmH20 range quickly.
Plateau Pressure: On an inspiratory hold of 0.5 seconds (at the end of the inspiratory
portion of breath cycle), measured pressure should be <30 cmH20 to minimize ventilator-
induced lung injury (VILI).
Emergency stop: There is an emergency shut-off button that turns off the device and allows
for manual override and standard use of the BVM. (Version 1)
Supplemental Oxygenation: Most BVMs have a port to blend-in oxygen. Room air is 21%
oxygen. Wall or tank-based oxygen is 100% oxygen. The higher the flow rate for ported-in
oxygen, the higher the fractional percentage of oxygen delivered to the patient. In acute
ventilator support, room air is often sufficient. Appropriate VT and PEEP are the keys to gas
exchange.

Viral Filtration: HEPA filters should be placed on the ETT connector and then the filter is
connected to the breathing circuit and BVM unit. This allows for all expired air at the point
of exit from the mouth to be filtered prior to entering the BVM which contains an open
aerosolization port.
Breathing Circuit: The use of single-line disposable breathing circuit aids in the maintenance
of heated and humidified air returning to the patient and also allows for placement of the
ApolloBVM at a safe distance from the patient.

[H] Compilation of other Ventilator designs based
on one of the above mechanisms
1. AmboVent
A group of researchers in Israel is developing an alternative emergency ventilator system
called the AmboVent-1690-108, based on a bag valve mask.
The research group, made up of Air Force electronics experts, robotics specialists and
medical professionals created the Ambu bag-based system with a motor, microprocessor
development board and an electronic circuit to connect to the ventilator and provide
automated, volume-controlled ventilation. Other off-the-shelf components include a
snowblower motor, a controller, a development board and a pressure sensor, according to a
report on NoCamels.com.
Researchers made 20 prototypes to send to physicians, clinicians and developers across the
world with the hopes of bringing the prototypes to regulators to fast track authorization.
The Israeli Health Ministry is currently evaluating the device and a trial on pigs is set to begin
at Hadassah Hospital in Jerusalem.
“It is not a medical device yet,” Dr. Eitan Eliram said in the report. “We need to do a few
more tests and build a better version. There’s a whole regulatory process but we are

receiving guidance from the Health Ministry on our path toward testing.” Given the
situation, he says, there has to be a way to “compress the process because the AmboVent
can save lives.”
2. WPI
Researchers at Worcester (Mass.) Polytechnic Institute (WPI) are touting a design for turning
inexpensive bag valve mask (BVM) resuscitators into automated ventilators to aid the fight
against the coronavirus outbreak.
The WPI team is designing the ventilators from readily available, manual BVM resuscitators
so that they can fill the gap between the number of ventilators available and the number
needed when COVID-19 is expected to peak, according to a news release.
Anyone with a 3D printer and a background in electronics and mechanical engineering may
be able to produce the ventilators for a local hospital, as the researchers intend to make
designs of multiple devices and components publicly available. The researchers also believe
a manufacturing company can use the designs to make the ventilators quickly and at scale.
3. OpenVent
As part of Infineon Technologies’ “Hackathon,” a team called OpenVent developed an open-
source ventilator with an Ambu-bag, much like the one in MIT’s E-Vent.

The Ambu-bag, plus maker components that include stepper motors, 3D-printed
components, motor drivers, sensors and Arduino-compatible software, are all part of the
open-source ventilator design aimed at offering a simple setup for helping treat coronavirus.
The design includes automation of the actuation of the Ambu-bag, which is usually done by
medical personnel. The design is optimized for 3D printing.
4. Coventor
The University of Minnesota is touting makeshift ventilators made from $150 in parts as
potential solutions amid the shortage of equipment at healthcare facilities during the
COVID-19 outbreak.
According to a report in the Star Tribune of Minneapolis, researchers tested the prototype
on a pig, keeping the animal breathing for an hour and confirming the possibility of building
these homemade devices to help during the coronavirus pandemic.
The researchers developed the mechanical ventilator as a compact device the size of a
cereal box that does not require pressurized oxygen or air supply, unlike commercially
available mechanical ventilators. According to a website dedicated to the device, dubbed
the “Coventor,” in collaboration with the university and local industry leaders, the
researchers acquired the necessary components to assemble thousands of ventilators per
week, with all of them currently shipping from Minneapolis.

A few weeks after first revealing their project, researchers at the University of Minnesota
announced that the FDA granted the Coventor emergency use authorization (EUA).
A Boston Scientific spokesperson told that the company will act as the sole manufacturer of
the Coventor, having brought the concept through its product development process in just
days.
Boston Scientific plans to begin with a limited run of products and scale up in accordance
with demand as the coronavirus outbreak continues to develop. The company will sell the
Coventors at cost — at approximately $1,000 per device.
5. AmbuBag (GeorgiaTech & Cranfield Univ.)
An international team of university researchers designed a low-cost ventilator using the
resuscitation bags carried in ambulances that are widely available in hospitals, too.
The device is powered by a 12-volt motor and is designed to be produced from inexpensive metal
stock and plastic gearing. It can also take power from standard wall adapters.
Researchers designed the device at Cranfield University in the United Kingdom before building and
testing it at Georgia Tech, in collaboration with Emory University. Cranfield professor Leon Williams
has been working on the designs with the researchers in Atlanta, according to a news release.

The research team has taken steps to collaborate with the Emory University Office of Technology
Transfer so that the design can be moved into the manufacturing phase.
“We are adapting the bag-valve-mask (BVM) resuscitators that are already in place, designed to be
manually squeezed for reviving a patient,” Georgia Tech Woodruff School of Mechanical Engineering
associate professor Shannon Yee said in the release. “We are providing the mechanical assist that
allows the bags to be squeezed continuously for days rather than for short periods of time. We are
using infrastructure already in place.”
The design has a unique aspect to it in that there are two BVMs per ventilator so that two people
can breathe using one of each device that is built. The airflow is separate between the one device so
that the users avoid cross-contamination and flow volumes can be controlled independently for each
patient’s needs.
A small number of ventilator devices designed by the research team has already been assembled for
bench testing and shared with hospitals in Georgia for evaluation.

[I] Risks : The Great Ventilator Fiasco of
COVID-19
One important device for which demand has ramped up is ventilators for patients who need
assistance with their breathing due to the respiratory effects of COVID-19. Major
manufacturers have increased production, while big names outside the medtech space have
also attempted to help with the shortage. But doctors in Italy are already having to decide
which patients get ventilators — and which do not.
While the manufacturers try to lend a hand, researchers all over have tried to find ways to
combat the shortage in coronavirus-fighting equipment by constructing makeshift, DIY
ventilators.
One caveat that remains is the fact that, while the FDA issued guidance on emergency use
authorizations that includes allowing alternative products used as medical devices, there is
no clear stance on whether homemade devices could potentially garner authorization. Some
wondered whether DIY ventilators will ever be put to use. The first such device has won
approval and more will look to follow in the coming days, weeks and months.
As health officials around the world push to get more ventilators to treat coronavirus
patients, some doctors are moving away from using the breathing machines when they can.
The reason: Some hospitals have reported unusually high death rates for coronavirus
patients on ventilators, and some doctors worry that the machines could be harming certain
patients.
Generally speaking, 40% to 50% of patients with severe respiratory
distress die while on ventilators. But 80% or more of coronavirus
patients placed on the machines in New York City have died, state
and city officials say.
- Dr. Albert Rizzo, CMO (American Lung Association)
And similar reports have also emerged from China and the United Kingdom. One U.K. report
put the figure at 66%. A very small study in Wuhan, the Chinese city where the disease first
emerged, said 86% died.

To make the situation worse, so many enthusiastic engineers who want to help out are
volunteering their expertise to develop a low cost ventilator that any manufacturing facility
could adapt to build. Most of the designs, centres around one key bit of technology - A BVM,
or bag valve mask.
As discussed in the above sections, BVM are plastic bags that a clinical care practitioner can
manually deflate with their hands. It’s what a first responder would use if a patient wasn’t
breathing, instead of giving mouth to mouth resuscitation. It’s a cheap and easy way to
force air into the lungs. All these designs are basically just robotic arms that can squeeze this
bag at a set frequency endlessly. They of course could be manufactured quickly and in great
numbers, but ventilators aren’t just air pumps that force air into a patient's lungs. One of
the primary problems facing doctors currently is managing a side effect of mechanical
ventilation, barotrauma.
To understand this we first need to understand how the lungs operate under normal
conditions. Two muscle groups typically act to control breathing: The Diaphragm: which is a
large muscle which separates the abdomen from the chest, and The Intercostal Muscles:
which are the muscles which reside between the bones of your rib cage.
When you breathe-in your diaphragm contracts, which causes it to move toward the
abdominal cavity, while the external intercostal muscles between the ribs also contract
which lifts the rib cage outwards. Both of these actions increase the volume of the thoracic
cavity, the cavity that your lungs reside in. The increase in volume causes a corresponding

decrease in pressure, which allows air outside the body at atmospheric pressure to fill the
lungs and equalise the pressure. The key thing to note here is that negative pressure drives
inhalation. The lungs don’t inflate like a balloon. They expand and equalize with
atmospheric pressure. On exhalation the process reverses with a small spike above
atmospheric pressure to push the air out again.
Mechanical ventilation cannot work like this. It has to force air into the lungs from the
outside and essentially blow the lungs up like a balloon. If this is not tightly controlled the air
pressure could work against the diaphragm and the intercostal muscles and end up
increasing the pressure in the alveoli above their typical max pressure. The alveoli are tiny
thin air sacs in the lung that are in contact with blood vessels to allow oxygen and carbon
dioxide to diffuse
between the blood and
the lungs. To do this
they have to be
extremely thin and
because of that they are
very delicate pieces of
tissue. Over expanding
them will lead to
inflammation at best or
rupture at worst. This is
what Barotrauma is. To
make this worse, those suffering from acute respiratory distress syndrome, like those
affected by Covid-19, are more at risk of suffering from this side effect of mechanical
ventilation, as the alveoli that are filled with fluid prevent air from entering them, causing
the pressure to elevate even higher in the functioning alveoli. The last thing we want to do is
damage the healthy tissue of a patient suffering from damaged lung tissue. That is the
opposite of helping [29].
To avoid damaging lung tissues, doctors need to carefully choose their settings on a
ventilator. The primary guidance for this is to limit the volume and pressure of air entering
the lungs. So, any low cost ventilator will need a method to control these settings. Designs
like this one, which can only vary its volume output, as appears from most of the designs
discussed in the report above, by connecting the push rod closer to the centre of rotation of
the cam. There is no sophisticated variable control in most of the cases. These kinds of
designs would likely do more harm than good.

However, it’s surprising to see big universities and even massive multi-million dollar
companies like Virgin Orbit, who present these designs as their own, have done very
minimal research into what is needed from a ventilator and just built something as quickly
as possible to get some positive PR for their organizations. As per our research on open
source ventilator design, the earliest design that proposed using these BVM was from an
MIT student project in 2010. This paper has been online that entire time and if people are
truly copying it, they are leaving out some clever design ideas that make it more functional.
As discussed in one of the sections above, their design included a spirometer, which
measures the air flow rate out of the BVM, by integrating this value they can calculate the
volume of air delivered. This then feeds into a controller which can vary how tightly the
BVM was squeezed to change the volume of air delivered. This gave the device a nice range
of tidal volumes ranging from 200 milliliters to 750. This is a better design, and may be
useful in a do or die situation. But, it is not perfect.
What’s missing in even MIT design?
The breaths per minute controller is simply set on a time based frequency, ranging from 5 to
30 breaths per minute. This is called a mandatory breath. It’s entirely determined by the
machine. You will take a breath whether you like it or not. This would obviously be

uncomfortable and requires the patient to be heavily sedated to the point of paralysis, but it
can also exacerbate barotrauma if the patient's diaphragm and intercostal muscles are
resisting the inhalation.
High performance ventilators can work like this, but they typically don’t. Their breath
sequences are normally triggered by the patient. They are still able to breathe. They just
need help because they are exhausting themselves with the effort. In order to do this the
machine needs some way of triggering the breath cycle and ending it too, based on
observations of the patient. This can be done in a number of ways. It can be pressure
triggered, where a sensor detects a drop in airway pressure indicating the thoracic cavity is
expanding. It can be flow triggered, where a sensor detects airflow into the lungs, or it can
be triggered by a sensor detecting electrical activity of the diaphragm, indicating that the
diaphragm is contracting to expand the thoracic cavity. This also requires very fast
microprocessors to detect and react to the triggers.
No low cost ventilators rapidly manufactured to fight Covid-19 (or to make
quick money?) incorporating this vital component of ventilator design.
And it truly is a vital component. A very difficult part of the ventilation process is weaning
people off it again. A ventilator which requires someone to be sedated to the point of
paralysis makes it very difficult to get them breathing naturally on their own again. There
are a multitude of other design considerations to be made with ventilators.
Some of the key things engineers must consider when designing these machines
COVID-19 patients frequently develop an acute respiratory distress-like syndrome, or ARDS,
which not only fills the alveoli with fluid, making gas exchange harder, but also increases the
likelihood of the alveoli collapsing shut at the end of every breath out. This is because
diseased areas of the lung don’t produce surfactant normally. Pulmonary surfactant is a
clever substance produced by alveolar cells which coats their inner surface and one of its
key jobs is keeping these tiny sacs open when the lungs are deflated, which is what happens
in healthy lungs. But in ARDS, when you breathe out, those alveoli collapse shut and
sometimes whole sections of the lung collapse, called Atelectasis. Trying to force them open
with every breath requires more pressure and hugely increases the risk of Barotrauma. So,
we use positive end-expiratory pressure or PEEP, to try to prevent this. To understand it
simply, imagine you’ve got your head out of the window of a fast-moving car with your
mouth open, don’t do this by the way, in addition to all the insects, you also have a constant

air pressure exerted on your airway, making it ever so slightly harder to breathe out. That’s
PEEP. PEEP is a constant positive pressure that prevents those alveoli collapsing at the end
of each breath and also helps open up collapsed areas of the lung.
In COVID-19 we are seeing patients requiring very high levels and tight control of PEEP to
maintain their oxygen levels and protect the lungs and this is something that a basic bag-
squeezing vent cannot really achieve. From the mechanisms used in most of the designs, we
must be careful about the possibility of baro and/or volu-trauma. Most of these patients are
on a ventilator for a few weeks at the moment. A basic bag-squeezer might be adequate for
the first day or so when a patient is deeply sedated, but simply won’t work as you try to
ease off the sedatives.
Additionally, your upper airways warm and humidify air entering the lungs, but they are
taken out of the equation by the endotracheal tube which goes directly into the lower
airways. Without the warming and humidifying features of modern ventilators, lung tissue
will get rapidly damaged.
So, as you can probably tell, there is a lot more to ventilation than just pumping air into a
patient. Tight regulation of Pressure, volume, oxygen percentage control and humidification
would all require more complicated mechanics than these simply BVM pumps. Designing a
ventilator fit for purpose with cheap and easy to manufacture components is a difficult job,
but we are positive a viable product will come to light soon. Especially as this is not a new
problem.
Poorer countries have been struggling with the lack of cheaper medical supplies for years
and there are affordable ventilators from a Noida based company AgVa, which uses an
android phone as the user interface. It was on the market long before this pandemic
started, and was designed to help poorer families treat their loved ones at home, so the
need for trained medical personnel to run it is lower too. We could find little information on
its capabilities, but the company has received massive orders from the Indian government
already.
Note: We are all in this together, and I hope this section doesn’t come across as a tear down
of well intentioned engineers trying to help. We understand that It’s much easier to point out
the flaws in a design than to actually put in the time to design something yourself. This
analysis is just an attempt to point people in the right direction.

Fig. 17 – PB 560 Open Design
[J] The Safest Bet : Medtronics PB560
Ventilator Design:
In light of the life risks involved with the other rapid ventilator designs, it’s safer to adapt
FREE open source PB560 design that the famous medical devices company Medtronics has
provided to the world as a gift to fight Covid-19 Pandemic. Surprisingly, Medtronic is making
available to anyone the full design specifications, produce manuals, design documents and,
even, the software code for its Puritan Bennett (PB) 560 portable ventilator hardware.
What all parts of PB560 designs are now open source?
Now in 6 different releases Medtronics has made
the following details related to its PB560 design
open for public:
Electrical schematics, Manuals, Manufacturing
documents, Requirements documents,
Manufacturing fixtures, Printed circuit board
drawings (including multiple BOMs), 3D CAD files,
Mechanical part drawings, Source code files,
Source code checksums, Accessories, Bills of
Materials (BOMs), BOM Drawings, Purchased Part
Drawings, Risk Documents, Compiled Software Files, Ventilator Accessories, 3D Model Files
in STEP Format, and Permissive License for all the above intellectual properties.
Few questions to understand more about PB560:
Q: Does Medtronic still make and sell the PB560?
A: Yes, Medtronic sells the PB560 ventilator in 35 countries around the world. Beginning in
May, the PB560 ventilator will also be available in the U.S., under an Emergency Use
Authorization (EUA) from the U.S. Food and Drug Administration (FDA).
Want to download all PB560 design files?
Touch base at futureis@patbnb.com

Q: Can Medtronic provide contact information for subcontractors/suppliers? Are we able
to purchase subsystems or components?
A: Medtronic suppliers are already at or beyond capacity meeting demand from Medtronic
to dramatically increase ventilator production. One of the goals of the open ventilator
project is to allow interested third parties to identify additional component suppliers.
Q: Why is Medtronic providing design specifications for the PB560 ventilator rather than
the newer PB840, PB980, or Newport™ HT70 ventilator platforms?
A: Ventilator manufacturing is a complex process that relies on a skilled and specialized
workforce, an interconnected global supply chain, and a rigorous regulatory regime to
ensure patient safety. Indeed, Medtronic sources more than 1,500 components to make
PB980 or PB840 ventilators. The PB560 ventilator, by contrast, is a smaller, more compact
ventilator that we think will help participants across industries to evaluate options for rapid
ventilator manufacturing.
Q: Can Medtronic help with product testing, make available test fixtures, or tell us how to
design test equipment?
A: A third party who manufactures a ventilator under the terms of the Permissive License is
solely responsible for the design, manufacture, distribution, installation, performance, and
service of their ventilator. However, as a reference, a verification and validation test
protocol is available on medtronic.com/openventilator. This includes a detailed description
of our test methods and the type of testing equipment used. Otherwise, we are unable to
support testing or share detailed designs of test equipment beyond what is already publicly
posted.
Q: Are there consumables specific to the PB560 ventilator required to operate the
ventilator that would also need to be manufactured?
A: Yes. The PB560 exhalation valve is required to operate the ventilator. This component is
single-patient use. Medtronic is currently investigating ways to ramp up production of this
exhalation valve component. Other consumables used with the PB560 ventilators, such as
patient circuits and filters, are available from Medtronic as well as other manufacturers.

References:
1. https://www.disabilityinnovation.com/news/frontier-tech-4-covid-action-emerging-market-
ventilation-systems
2. https://www.medrxiv.org/content/10.1101/2020.03.24.20042234v1.full.pdf
3. https://www.medicinenet.com/script/main/art.asp?articlekey=31723
4. https://en.wikipedia.org/wiki/Tidal_volume
5. https://en.wikipedia.org/wiki/Ventilator
6. https://en.wikipedia.org/wiki/Bag_valve_mask
7. https://www.ncbi.nlm.nih.gov/books/NBK441924/
8. https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1365-2044.1961.tb13830.x
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ventilators-for-13bn-people-a-worry/ar-BB11ynv5
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how-india-is-trying-to-overcome-ventilator-shortage-5095201.html
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13. https://e-vent.mit.edu/
14. https://onlinelibrary.wiley.com/doi/full/10.1111/anae.15063
15. https://3dprint.com/265067/3d-printing-for-covid-19-part-three-open-source-ventilators/
16. https://onlinelibrary.wiley.com/doi/epdf/10.1197/j.aem.2006.05.009
17. https://e-vent.mit.edu/clinical/#101
18. https://youtu.be/tpOST90lbj4 (RICE)
19. https://youtu.be/78Gg602LPv8 (RICE)
20. https://youtu.be/1t2t8d8xtD0 (RICE)
21. https://youtu.be/Dp53KfznF4k (Dunno)
22. https://youtu.be/qt50N0i0Rgs
23. https://youtu.be/_XB5A9KIQBM
24. https://youtu.be/RpEqtGa2vTI
25. https://youtu.be/tfpG_ZUk1H0
26. https://youtu.be/DdQg11QgpXg
27. https://youtu.be/vdLXp7uGFX4
28. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5594148/
29. https://youtu.be/7vLPefHYWpY (Risk of Using Mechanical DIY ventilators)
30. https://youtu.be/BSxXGv0Xsls (Medtronics PB560 design review)
31. https://www.jto.org/article/S1556-0864(20)30132-5/pdf
32. https://www.ncbi.nlm.nih.gov/books/NBK545226/
33. https://opentextbc.ca/anatomyandphysiology/chapter/22-3-the-process-of-breathing/
34. https://emedicine.medscape.com/article/296625-overview
35. https://books.google.co.in/books?id=oUNxDwAAQBAJ&redir_esc=y
36. https://www.agvahealthcare.com/covid-19
37. https://www.agvahealthcare.com/models

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