The Medical Ventilators are also known as Mechanical Ventilators, Artificial Ventilators etc. We will henceforth refer all these as Ventilators. When a patient breathes on its own it is known as Spontaneous Breathing and when the patient is unable to breathe on its own we use a device called Ventilator which helps the patient breathe artificially. This is called Mechanical Ventilation and is a method to mechanically assist the patient to breathe and in extreme cases replace the entire breathing process. Spontaneous breathing is done by a process called Respiratory System.

1. Health technology is defined by the
World Health Organization as the "application of
organized knowledge and skills in the form of devices,
medicines, vaccines, procedures, and systems developed
to solve a health problem and improve quality of lives“

2. MECHANICAL
VENTILATORS
Compiled by Dr. S.B.Sinha- Ex President Biomedical
Engineering Society of India
Health Technology Management Serie

3. MECHANISM OF
BREATHING

4. MECHANICAL VENTILATORS-
WHAT??
A medical ventilator is a Medical
Device designed to mechanically force
breathable air (mixture of Air and
Oxygen) into and out of the lungs, to
provide the mechanism of breathing
for a patient who is physically unable
to breathe, or breathing insufficiently.
The ventilators are either Positive or
Negative pressure. However Negative
Pressure Ventilators are rarely used.
Only Positive Pressure Ventilation is in
use

5. TYPES OF VENTILATORS

7. COMPONEN
TS OF A
VENTILATO
R
1, Power Supply
2. Air and Oxygen Hoses and Blenders.
3. Humidifier.
4. Patient Circuit
5. Inhalation and Exhalation Valves.
6. Flow Sensor.
7. Water Traps.
8. Control Circuits.
9. Switches and Fuses.
10. Other Electronic Hardware like Displays and Knobs.

8. COMMON VENTILATOR
COMPONENTS
Humidifier Patient Curcuit Air and Oxygen Hose
Air/ Oxygen Mixer
(Blender)

9. BASIC VENTILATOR PARAMETERS
1. Tidal Volume 2. Frequency.
3. PIP or Peak
Inspiratory
Pressure.
4. Positive End
Expiratory
Pressure or PEEP
5. Inspiratory
Time.-Ti
6.Expiratory
Time.-Te
7. I:E Ratio

10. VENTILATOR ALARMS
A ventilator alarm is a safety
mechanism on a mechanical
ventilator that uses set parameters
to provide alerts whenever there is
a potential problem related to the
patient-ventilator interaction.
Common Ventilator Alarms are:
1. High Pressure Alarm.- Due to an
obstruction in ventilator circuits or
ET Tube
2. Low pressure Alarms by leaks
3. Low expired volume alarm- 4.High Frequency Alarm-
5. Apnea Alarm- when no
expiration for preset time.
6. High and Low PEEP Alarm

11. NORMAL PARAMETERS SETTINGS
OF VENTILATOR
1. Tidal Volume- 5-
15ml of body
weight.
2. Respiratory Rate-
10-20 bpm for
adults and 20-60
bpm for pediatric.
3. Oxygen
Concentration-
FiO2- 21-90%
4. I:E Ratio- 1:2
5. Flow Rate- 40-
100 lpm
6. Sensitivity
Trigger-0.5- 1.5
cm H2O
7. Pressure Limit-
4-25 cm H2O
8. PEEP- 5-10 cm
H2O

12. MODES OF MECHANICAL
VENTILATOR
1. Controlled
Mandatory
Ventilation. CMV
2. Assist Control
Mandatory
Ventilation- ACMV
3. Synchronised
Intermittent
Mandatory
Ventilation- SIMV
4. Positive End
Expiratory
Pressure.- PEEP
5. Continuous
Positive Airway
Pressure.- CPAP
6. Pressure Support
Ventilation- PSV

13. VENTILATION PHASES

14. VENTILATOR PHASE VARIABLES
1. Trigger- By
Ventilator- time; By
Patient- pressure or
flow.
2. Limit- Flow
Limited or Pressure
Limited

15. MODES IN
VENTILATIO
N
2. Describes the breath support based on
relationship between various possible types of
breath and inspiratory-expiratory phase variables
1. Modes are process by which the mechanical
ventilator determines, either partially or fully, when
the mechanical breaths are to be provided to the
patient, thus determining the breathing pattern of
the patient during mechanical ventilation.

16. BREATH TYPES

17. BREATH
TYPES
1. Controlled Breath- When the patient is not
breathing at all. All the ventilation is delivered by
the Ventilator. No work of breathing by patient.
2. Assisted Breath- When patient tries to breath
and Ventilator takes over the work of breathing.
3. Supported Breath- When patient is able to do
some or most of the work of breathing. Ventilator
supports to finish the breathing.
4. Spontaneous Breath- When patient breathes on
its own.

18. CMV- CONTROLLED MANDATORY
VENTILATION

19. CMV-
CONTROLL
ED
MANDATOR
Y
VENTILATIO
N
1. Patient can’t breath on its own.
2. Patient can’t change the respiratory
rates.
3. Suitable only when patient is not
making any breathing efforts and is
under sedation or because of a disease.

20. ASSIST CONTROL
MANDATORY
VENTILATION
In Asst Control Mode the
patient tries to breathe but
the breathing is still
delivered by the patient.
Patient is not allowed to
breath on its own.

21. SIMV-SYNCHRONISED
INTERMITTENT
MANDATORY
VENTILATION
This mode is used when the patient has started
breathing. Thus patient breathing is synchronized
with the ventilation by the ventilator. The patient
will be allowed to breathe and when it is unable to
breathe the ventilator will provide the breathing.
The patient's bpm is set as per requirement and this
breathing is guaranteed to the patient but this
consists of partially the patients breathing and
partially by the Ventilator.

22. SIMV-CONTD.
The Ventilator delivers either
patient triggered assisted
breath or time triggered
mandatory breaths in a
synchronised manner so as to
avoid ventilator fighting with
the patient.
If the patient breathes
between mandatory breaths,
the ventilator will allow patient
to breath by opening the
demand (inspiratory) valve but
not offering any inspiratory
assistance.

23. PCV- PRESSURE
CONTROLLED
VENTILATION
In his Mode the inspiration Cycle
maintains a pressure limit set by the
machine. The Volume may not be
guaranteed but pressure will never
exceed the Maximum pressure set in
the Ventilator. In Pressure Controlled
Mode inspiration is terminated when
a specific airway pressure has been
reached. The ventilator delivers a
preset pressure; once this pressure
is achieved, end inspiration occurs.

24. PRESSURE SUPPORT VENTILATION
The patient breathes spontaneously while the ventilator applies a pre-determined amount of positive pressure to the
airways upon inspiration.
Pressure is the setting Variable.
No mandatory breath.
Applicable on spontaneous breath in any mode.
Patient effort determine the size of breath and Flow rate.
No back up ventilation in event of Apnes.

25. CPAP-
CONTINUO
US
POSITIVE
AIRWAY
PRESSURE
CPAP- Is the continuous positive airway pressure
applied to spontaneously breathing patients.
A continuous elevated pressure is provided to the
patient circuit to maintain adequate oxygenation
and decrease work of breathing.
CPAP can be used invasively through ET Tube or
non invasively through a Mask.
It may be used during weaning.

26. BIPAP- BILEVEL POSITIVE AIRWAY
PRESSURE
BiPAP is a noninvasive form
of mechanical ventilation
provided by means of a nasal
mask or nasal prongs, or a
full-face mask.
The system allows the
clinician to select two levels
of positive-pressure support:
An inspiratory pressure
support level (referred to as
IPAP)
End expiratory pressure
called EPAP (PEEP/CPAP level).
•There are Ventilators which perform
both BIPAP and CPAP functions and
are known as BIPAP Machines

27. CPAP AND
BIPAP WAVE
FORM

28. HIGH FREQUENCY
VENTILATORS
- In some advanced
ventilators this mode is
present. High-frequency
ventilators use small tidal
volumes (1 to 3 mL/kg) at
frequencies greater than
100 breaths/minute.
The high-frequency
ventilator accomplishes
oxygenation by the
diffusion of oxygen and
carbon dioxide from high
to low gradients of
concentration

29. INSTALLATION OF A VENTILATOR
1. Connect the
Power Supply
cable.
2. Connect the
Air and Oxygen
Sources.
3. Assemble the
Humidifier and
patient circuit.
4. Connect a
test lung.
5. Switch ON the
Ventilator.
6. Do the
minimal testing.
7. Connect to
the patient

30. QUICK TESTING BEFORE USE
1. Attach the Calibrated Test Lung of 1 litre with Max Volume Set at 650 ml
2. Switch ON and Quick Check Test Parameter set as below:
a) Mode- Asst Control/CMV
b) TV- 500 ml
c) RR- 15 bpm
d) Ti= 1.3 Sec
e) PEEP= 5 cm H2O
f) FiO2= 60%
g) Waveform- Square
3) i) Check the PIP display. It should be 27 cm H2O+/-2
ii) Check the FiO2 display- It should be 60%+/-3%

31. TROUBLESHO
OTING
COMMON
PROBLEMS.
1. Power Supply- Check the cable
and wall outlet for AC Power supply
if the Ventilator is not switching ON.
2. If there is problem in Oxygen
check the Oxygen Supply.
3. If there is alarm check for
occlusions, leaks, and filters.

32. PREVENTIVE
MAINTENAN
CE
Cleaning-
a) Remove any dust, dirt, water, waste matter, tape and paper
daily.
b) Clean inside and outside with damp clothes and dry off weekly
c) Remove dirt from wheels and other moving parts on a weekly
basis.
Audiovisual Checks:
DAILY
a. If any leak is audible, check with soapy solution.
b. Check all seals, connectors, adapters and parts are tight.
c. Check all moving parts move freely, all holes are unblocked.
WEEKLY
a) Check connections for leaks with soap solution and dry off.
b) Check all fittings and valves for proper assembly.
c) Replace and deteriorated tubing and hoses.
d) If seal, plug, sockets are damaged replace them.

33. CALIBRATION FOR
PRESSURE
1. Construct a manometer to measure pressure in centimeters of H2O.
a. Use a large non-inflatable jug as the reservoir. Most water jugs will work.
b. Fill the jug half-full with water.
c. Insert the patient output from the ventilator into the plastic jug. Also insert one end of the clear plastic tubing
into the plastic jug. The end of the plastic tube should be near the bottom.
d. Seal the tubes with latex gloves and tape. Insure that no air can escape from the jug opening.
2. Set the pressure limit on the ventilator. Record this pressure in Table 1 below.
3. Hold the clear plastic tubing straight up. Use a tape measure to measure the peak height of the water in cm
H2O. Measure from the water level in the jug to the maximum height reached in the clear plastic tubing. Record this
measurement . The height of the water is the pressure.
4. Repeat Steps 2-3 for four settings of pressure.
5. To determine if the ventilator is accurate enough, show your table to the physician that uses the ventilator. The
set and measured reading should match.

34. CALIBRATIO
N FOR
VOLUME
4. Turn ON the Ventilator. Allow the Ventilator to deliver 01 breath. The top of graduated cylinder
should fill up with Air as shown in figure below. Now stop the Ventilator. Read the air level that has
displaced the water level. This is the tidal volume. Repeat the process and take four readings and
tabulate in table. The Set and measured value should match.
3. Connect a tube to the output of the ventilator (normally the tube leading to the patient would be
connected here). The other end of the tube is placed within the measuring cylinder.
Lift the measuring cylinder up, close to the water level as fig below. Note down the exact level of
water in the measuring cylinder (if it is not completely filled with water).
2. Then, turn the measuring cylinder up by 90 degrees so it sits up-side-down in the basin.
1. Ensure that the patient output tube is at least 80 cm long. Set the tidal Volume to 500 ml which
is the average tidal volume for adults. Fill a plastic tub with water. The tub should be big enough
to accommodate a 1 litre graduated cylinder.

35. THANK YOU- Q/A(IMAGE-EE TIMES)