The Device called VITAL (Ventilator Intervention Technology Accessible Locally) is developed by a Team of Mechatronics Engineers and Scientists from NASA, USA. VITAL is intended to Last Three to Four months and is specifically tailored for COVID-19 patients.
What is the difference between VITAL and Conventional Ventilators?
NASA ventilator won’t replace current hospital ventilators, VITAL is intended to last just three to four months. The functions are limited. Conventional Hospital ventilators are designed to apply Respiratory Therapy through various modes of ventilation. While VITAL is a basic functional ventilator which can perform high pressure ventilation.
High Pressure means its ability to generate High Inspiration Pressure to Inflate lungs. Conventional ventilators usually offers upto 50 cmH2O and regular a patient setting can be 20 to 35 cmH20. The Printed Label(grey area in below image) on VITAL indicate that peak pressure can be upto 100 cmH2O, but the specifications are not yet available.
It is noted that many COVID Ventilator Prototypes are using Ambu Bag Mechanism. Most of them are not having FiO2 (See below) settings which is an essential parameter for Patient oxygenation. It's mainly due to the lack of a High Pressure Air and O2 Mixing Chamber. VITAL seems to be configured in a promising manner.
Let’s Look at the Settings of VITAL :
Settings (Blue area : a to f)
a) FiO2 (Fraction of Inspired oxygen) :
It is the percentage of Oxygen present in breathing air inhaled by a Patient. Operator can set FiO2 level from 21 to 100%. The device mix Air and Oxygen to achieve Target FiO2 setting.
b) PEEP (Positive End Expiratory Pressure) :
PEEP is the Pressure required to be maintained inside the lung at the end of expiration. This will prevent lungs from collapsing. A diseased patient may tend to make complete exhalation and the empty lung may get collapsed. By maintaining peep pressure, exhalation valve closes as soon as airway circuit pressure reaches the PEEP set value. Unit is cmH2O (A unit of pressure).
c) Tidal Volume
This is the Volume of air pushed into the lungs during Inhalation Time. See inhalation time setting (f). Tidal volume is set according to patient Ideal body weight. Unit is ml, usually range from 400 ml to 800ml.
d) Backup Rate (bpm)
This indicate the minimum number of Inhalation (or exhalation) to be performed by a Ventilator or Patient. Number of Breath Delivered in a minute can be combination of Breath based on given Backup rate. Total Number of Breaths performed by patient can be higher than backup rate settings, if patient is capable of breathing at higher rate. Total Respiration rate is displayed in Outputs (See h).
e) Peak Pressure
This is the Maximum allowed Lung Pressure during the delivery of Tidal Volume. The Machine will limit Inhalation pressure to this value and prevents Lung damage. Unit is cmH2O
Note : Lung pressure varies according to Lung compliance. A diseased lung can be stiff compared to a normal lung.
f) I Time (Inspiration Time)
This is the Time provided for the Ventilator to deliver Tidal volume to the Lung. Unit is seconds (Sec). The ventilator calculate flow rate according to Inspiration Time and Tidal Volume which ensure the gas delivery within the Inspiration Time. The Inhalation valve will open during this period. Usual set value is 1.2 Sec, 1.5.Sec.
Note : Inspiration & Expiration Ratio(I:E), Expiration Time settings are not found in this ventilator. This may be due to its objective of simple operation configuration.
Outputs / Monitored parameters (Grey area : g to i)
These Values are measured during gas delivery using Pressure and Flow sensors.
g) LED Bar Graphs for Tidal Volume & Pressure
These LED Bar graphs will indicate the Rise in Lung Volume and Lung Pressure during Inspiration Time (Tidal Volume, Peak Pressure). Basically it will glow up and down during Inspiration and Expiration.
h) Respiration Rate
This indicate actual number of Breaths taken by the patient. The Actual breath rate can be higher than Backup rate. It varies as per patient efforts.
i) Minute volume
This is the volume of air inhaled by a patient in a minute. It is calculated by
multiplying Respiration rate(g) and Tidal Volume(V). Unit is Litres/Min
ALARMS ( j )
A column of Red LED’s found on left side of the VITAL for visual alarms. It may include Audio alarm.
i) PEEP : It Alarms if Peep Measured in Breathing circuit is lower than set PEEP. This Occur if there is a leakage in Patient circuit or if circuit get disconnected or any valve failure.
ii) TIDAL Volume : It Alarms if Tidal volume delivered is lower than set Tidal
volume. It occurs due to many reasons. Example: Limitations due to Peak Pressure setting (e), Circuit Leakage, etc.
iii) Respiration Rate : It Alarms if Actual Breath rate is lower than Backup rate.
iv) FiO2 : It Alarms if Oxygen percentage (FiO2) in delivered gas to patient is lower than Set FiO2. It may result due to low O2 gas supply pressure (Cylinder or pipeline), Technical issues in Mixing gas chamber, Oxygen sensor failure, etc.
v) Other Alarms : Settings for Machine Failure and Power failure .
What VITAL don’t have ?
Settings for Assisted, Support and Spontaneous Breath Modes
Trigger, Cycling Settings
Waveforms & Loops
Other Advanced settings for Oxygenation
What makes VITAL a Ventilator Technology Accessible Locally ?
Most of the Major Ventilator manufactures stopped their production due to the unavailability of its specially designed components from vendors. VITAL is designed with locally sourced available parts from existing supply chain sources, that means it doesn’t includes custom designed components. NASA says it can be built more rapidly than traditional ventilators.
NASA seeking expedited FDA (US Federal agency: Food and Drug Administration) approval for this device via an emergency use Authorisation. The Prototype is tested in Human Simulation Lab in the Department of Anaesthesiology
Author is a Senior Trainer at Harvey Biomedical
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