Newhart Technology

8/14/2019 Newhart Technology

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NEWER VENTILATORS

WHAT MAKES THEM

DIFFERENT ?John Newhart CRTT. RCP.


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PURITAN BENNETT MA-1


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Puritan Bennett MA-1

First released August 1967.

Simple to use

Basic IMV system (non-sync).

Bellows spirometer for exhaled gas

measurement.


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SIEMENS 900 C


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SIEMENS 900 B/C

900 B available in the USA early 70s..

Time limited and minute volume preset.

Patient or time cycled or SIMV.

Expiratory flow monitoring.


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BEAR I

Built in SIMV.

Monitoring of tidal and minute volume.

Pneumatically and electrically powered,

electrically controlled volume limited.

Time or patient cycled, control or

assist/control modes.


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PURITAN BENNETT 7200

Released 1983 First widely accepted microprocessor

controlled ventilator in USA.

Software upgradable.


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Newer Generation Ventilators


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TRANSPORT VENTILATORSEARLY MODEL


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PULMONETIC LTV 1000


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PULMONETIC LTV

Compact lightweight 12.6 lbs.

Ability to transport more critical patients.

Internal battery.

Volume Control, Pressure Control and Pressure Support.

Volume and pressure alarms and monitoring.


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Changes in Ventilators Include...

More sophisticated hardware.

More compact size.

Multiple high speed microprocessors.

Backup battery systems.

Graphical User Interface (GUI).

An ever expanding list of modalities.


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Modular Design

x Touch Screen Display

can be mountedseparately

x Breath Delivery Unit weighs only 40 lbs.

can be mountedseparately from cart


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New Hardware

Proportional control valves

Active Exhalation valves

Battery backup

Miniature blower


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Proportional Control Valves

One or two valves (O2, Air, or both)

proportionally open or close to control the flow ofgas to the patient circuit.

Responsible for FIO2, Flow rate, Flow waveform.

Microprocessor controlled.

Each valve is controllable from 1,000-4,000 steps.


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Two Proportional Valve SystemNPB 7200-840, DRAGER E2-4, SERVO 300

O2

AIR

To Patient

50 psig

50 psig

Each gas has its own solenoid, flow sensor and pressure regulator .

Both valves controlled by microprocessor.

FLOW SENSOR

FLOW SENSOR


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Single Proportional System

Hamilton Veolar, Bird 6400-8400st

O2

AIR

To Patient

50 psig

50 psig

BLENDERRESERVOIR

10-15 PSIG

Air and O2 are mixed in a blender, stored as a mixed gas in a

reservoir then pass through a single proportional valve.

PROPORTIONAL VALVE


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Pneumatics Chassis (PB 840)


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Blower with Intragral Digital

Blender

O2

Pulmonetic LTV Turbine/Blender System

Blended gas to patient

Delivery Control

Valve


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Active Exhalation Valves

The inspiratory and expiratory valves are active during

inspiration to maximize the reproducibility of inspiratory

and expiratory events.

These valves are critical in newer modes such as APRV,

BiLevel, and ATC.

With an active exhalation valve, the ventilator moves the

exhalation valve off of its seat during exhalation. With a

non-active valve the patient must push the valve off of its

seat adding to expiratory resistance and work of breathing.


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Active Exhalation Valve

During inspiration, the valve is closed with the force of the insp

pressure setting

Allows coughing or spont breathing at upper pressure level by venting

excess pressure and flow (PCV or BiLevel)

40PCIRCcmH2O

INSP

L

min

EXP

30

20

10

0

10

-20

80

60

40

20

0

20

-80

40

60

V.

0 4 8 12s2 6 10

Spontaneous Efforts Spontaneous Efforts

PCV W/O Active Valve PCV with Active Valve


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Two Proportional Valve System

With Active Exhalation Valve

O2

AIR50 psig

50 psig

Air and O2 solenoids combined with active exhalation valve.

PATIENT

EXH


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Microprocessor Control

Each new generation of ventilator incorporates

faster processors. Multiple high speed processors improve the

ventilators response to the patients needs.

Faster processors make more informationavailable to the clinician.


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MICROPROCESSOR

FUNCTION

During each breath, the ventilator switches through multiple

algorythims. These determine sensing of patient breath, rise rate of

breath, criteria for patient termination of breath at various points during

the breath, and ventilator initiated termination of breath.

Monitored data as well as data needed for ventilator function are

constantly being processed in the background.

Most calculations done by the ventilator are never seen by the user.

Most modes of ventilation that have come out in the last 15 years

would be impossible without computer control.


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UPGRADABILITY

Older ventilators frequently required a complete factory

overhaul to have one mode added. Upgrading newer ventilators is usually accomplished by

software upgrade. This may be done by changing out the

chip set or uploading software from a PC.

Adding options/modes typically involves changing a chipthat accesses specific options included in the software, or

entering a code number through a keypad.


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Battery Back-Up

Is now standard on most ICU ventilators.

Eliminates interruptions in ventilator function duringflickers or short term failure in A/C power.

Aids patient safety.


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GUI

Graphical User Interface

Touch screen technology.

Becoming the norm for ICU ventilators. Replaces traditional knobs, buttons etc.

Blends graphical displays with controls.

Easy software upgrades.

Gives additional information relative to

setting changes.


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Ease of Use - Software Controlled Screens Only current modes and settings are displayed (ease

of use)

Information can appear as needed to help make

decisions easier and safer


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Automatic Tube Compensation

Overcomes the resistance to flow created by an

endotracheal tube or tracheostomy tube.

Gives the patient the sensation that they are not

intubated.

Most important during spontaneous breaths.

May provide a calculated tracheal pressure curve on

the graphics display (E4).

Can be used to train the respiratory muscles.


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ET. Tube Resistance During

Breath Types

Mandatory breaths from the ventilator

easily overcome the resistance of an ET.

tube.

Spontaneous breaths are more difficult as a

result of breathing through a relatively

small orifice.


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ATC Function During Inspiration

During inspiration , the ventilator increases

pressure at the top of the ET. tubeproportionate to the inspiratory flow rate.


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Function of ATC during

Exhalation

During expiration the circuit pressure is

decreased below the PEEP level. Thetracheal pressure is held constant at the

selected PEEP level. This decreases the

work of expiration. The circuit pressure is

calculated from the expiratory flowrate.


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ATC with Paw and Ptrach

waveforms displayed


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Pressure Calculation

Using the flow measured by the ventilator, the

difference in pressure at any given time can

be calculated by the following equation:

Pressure = Rtube

Coef. X Flow2, where tube

resistance R is itself dependent on the flow.


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Difference Between ATC and PS

PS is a user set, fixed pressure that remains

constant throughout the inspiratory phase

irrespective of the patients flow rate. ATC is a user set level of compensation (1-

100%). The driving pressure will vary

according to the E.T. tube size set,compensation level and inspiratory flow

rate.


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CONCLUSIONVentilator Design

The design of ventilators depends increasingly

on the use of microprocessor control and

software.

The hardware in ventilators is being

continuously miniaturized.

Move towards ventilator designs that willventilate infants through adults.


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CONCLUSIONModes of Ventilation

Modes and hardware that minimize the overall work of

breathing.

Modes that make decisions based on both input from

the therapist and patient monitoring.

Interfaces that display more graphical and numerical

information.

Smart Alarms that look for combinations and severity

of thresholds. The alarm indicates by sound and/or

graphics the seriousness of the condition.

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