Learning Ventilator through Images

1 .The Below Picture gives an Overall Image of a Ventilator in Clinical Settings

2 . Invasive & Non Invasive Ventilation

Image(i) Patient Intubated using EndoTracheal tube

Image(ii) Patient Connected using Mask

3. Patient Intubation Procedure

Image (1) : ET Tube(EndoTracheal Tube) Inserted with help of Laryngoscope.

Image (2) : ET Tube connector to Patient Circuit (Connected to Y Junction of Inspiration&expiration Limbs).

4. Placement of Electrically Heated Humidifier

Dry air flow can damage Respiratory track and Lungs. A Humidifier is Placed in Inspiration Limb in Series. Medical grade Distilled water added upto the mark.

5. Sensors for Ventilator

i) Pressure, ii) Flow, iii) Oxygen Sensors

Oxygen Sensor Types : Galvanic & Paramagnetic Types of sensors Usually Installed in Inspiration Block as well as inside the Ventilator 

Flow Sensors Types : Measure Flow L/Min

With Help of Flow sensors, Ventilator can calculate Delivered Tidal Volume.

i) Differential Pressure (Proximal Flow Sensor)

ii) Heated Wire Anemometer Flow Sensor

6. Gas Supply ( Air & O2 )

Apart from Electricity, Ventilator Requires High Pressure Air and Oxygen Supply. Pressure Range can be 40- 55 Psi. It is supplied through Hospital Gas pipelines.

Note : Transport ventilators have Inbuilt Turbine or Blower which can directly take Atmospheric Air. It needs only High Pressure oxygen from a Cylinder.

Test Lung : Test Lung is used to Test Set Parameters before the Gas Delivery to Patient.

Test Lung replicates the Compliance and Volume parameters of a Normal Lung.

7. Operating Setting

User need to select a Specific Mode for Operating Ventilator.

Example : ACMV (Assist Controlled Mandatory Ventilation)

ACMV can opt for Volume controlled(VC) or Pressure Controlled(PC) mode.

So, there are Two modes available as i) ACMV-VC, ii)ACMV-PC

User also need to configure parameters like Breath Rate(RR), Inspiration Time, FiO2 etc.

(Read my previous article on Basic Ventilator by NASA to know this parameters)

8. Test Lung

Test Lung is used to verify the Gas Delivery for the configured mode. It is also used to Test the Ventilator. Test Lung specifications varies for Adut, Pediatric and Neonatal applications.

Specifications like Compliance and Maximum Tidal Volume of Test Lung will be Marked on them. Test Lung is disconnected after verifying the Gas Delivery and then Limb circuit is connected to Patient. Gas delivery to patient starts by pressing 'START' Button on ventilator. Usually a Long press is required.

9. Waveforms

The Pressure, Flow Sensors of Ventilator monitors the Gas delivery to patient and it generates Graphical Representations against Time as follows.

Graphs of 1) Pressure, 2) Flow 3) Volume

X Axis for Time, Y Axis indicates cmH2O for Pressure, L/min for Flow, ml for Volume.

Each rise in graph indicates a Gas Delivery (Breath) to patient.

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Note : This Article serves purpose of Basic learning. Do not attempt operating ventilator based on this material

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