Ventilation Mini Manual - Mode and Function Guide March 2015

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Dräger Ventilation Mini Manual

Brief explanation of ventilation modes and functions

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PC-BIPAP VS. PC-AC

PC-BIPAP vs. PC-AC

Pressure Control – Biphasic Positive Airway

Pressure vs. Pressure Control – Assist Control

PC-BIPAP

PC-AC (BIPAP ASSIST)

–– machine- or patient-triggered, mechanical strokes with inspiratory

synchronisation

–– spontaneous breathing possible at any time

–– back-up frequency

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PC-BIPAP VS. PC-AC

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D-7523-2014

With PC-BIPAP the patient can breathe spontaneously at any time, while

the number of mandatory strokes is pre-set. In this mode, the mandatory

strokes exhibit both an inspiratory as well as expiratory synchronisation

with the patient’s breathing efforts. If the mandatory stroke is reduced

due to expiratory synchronisation, the subsequent mandatory stroke is

extended. The inspiratory synchronisation shortens the expiration phase.

In this case, the subsequent expiration time is extended by the missing

time. This ensures that the set mandatory breathing frequency (f)

remains constant. Machine-triggered mechanical breaths are applied if

no spontaneous breathing is detected during the inspiration trigger

window. The patient may receive Pressure Support (PS) during

spontaneous breathing at the PEEP level.

Fig. 1 (PC-BIPAP with mandatory and spontaneous mechanical breaths)

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PC-BIPAP VS. PC-AC

D-7529-2014

With PC-AC, every attempt to breathe that is detected on the PEEP

level triggers a mandatory mechanical breath. This means that the patient

determines the time and the number of mandatory mechanical breaths.

To give the patient enough time for expiration, it is not possible to trigger

another mandatory breath directly after a mechanical breath. A mandatory

breath is applied (backup frequency), if no mechanical breath has been

triggered after the expiratory time has elapsed.

Fig. 2 (PC-AC with triggered and untriggered mechanical breaths)

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PC-APRV

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PC-­APRV

(Pressure Control – Airway Pressure Release Ventilation)

–– pressure-controlled

–– time cycled

–– machine-triggered

–– spontaneous breathing under continuous positive breathing pressure

with brief pressure relief times (screenshot)

In PC-­APRV, the patient’s spontaneous breathing takes place at the

upper pressure level Phigh. This pressure level Phigh is maintained for the

duration of Thigh. To achieve active expiration, the pressure is reduced for

a brief period from Tlow to Plow. To support CO2 elimination, the pressure

is then reduced to Plow for the brief period Tlow. The alternation between

the two pressure levels is machine-­triggered and time-­cycled. The

breathing volume (VT) that expired during the relief times, results from

the pressure difference between Plow and Phigh and the lung mechanics.

If the resistance or compliance of the lungs changes during the

ventilation treatment, the supplied tidal volume (VT) and thus the minute

volume MV may also vary.

During the activation of AutoRelease, the duration of released pressure

is determined by the expiratory flow trace. The Exp. term. setting

determines the percentage by which the expiratory flow must fall short of

in relation to the peak flow for the ventilation to return to the high

pressure level.

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PC-APRV

D-7540-2014

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D-7539-2014

Fig. 1 (PC-APRV with AutoRelease on and measured Tlow in seconds)

Fig. 2 (PC-APRV with spontaneous breathing on Phigh level)

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VC-MMV + AUTOFLOW

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VC-MMV + AutoFlow

Volume Control – Mandatory Minute Volume + AutoFlow

–– volume-controlled ventilation to backup a mandatory minute volume

–– the mechanical breaths are automatically and gradually reduced for

patients with increasing spontaneous breathing, which is possible at

any time

–– enables automatic weaning by reducing the mechanical breathing

frequency and

–– necessary ventilation pressure

VC-MMV behaves in a similar manner to VC-SIMV; however, the

mandatory breaths are only administered if the spontaneous breathing is

insufficient and falls below a set minute volume. If the spontaneous

breathing increases, fewer mandatory breaths are administered. This

allows VC-MMV to ensure that the patient always at least receives the set

minimum volume MV (MV=VT*f). The applied mechanically triggered,

timed breaths are synchronised with the patient’s inspiratory efforts. This

ensures that spontaneous breathing is always possible for the patient at

the PEEP level. If the patient’s spontaneous breathing is sufficient to

achieve the set MV, no further mandatory breaths are applied. This

means that the set breathing frequency (f) is the maximum number of

mandatory breaths. The patient may receive Pressure Support (PS)

during spontaneous breathing at the PEEP level. Every inspiratory effort

by the patient at the PEEP level, which meets the trigger criteria, triggers

a pressure-supported mechanical breath. The time, number and duration

of the pressure-supported mechanical breaths are determined by the

patient’s spontaneous breathing.

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VC-MMV + AUTOFLOW

AutoFlow (AF) ensures that the set tidal volume (VT) is applied with the

minimum necessary pressure for all volume-controlled, mandatory

breaths. In the event of changing resistance (R) or compliance (C), the

pressure is gradually adjusted in order to administer the set VT. Both the

pressure and the flow are adapted automatically. The patient is able

to breath spontaneously during the entire breathing cycle, during

inspiration and expiration.

MV

Set MV

Mandatory MV

Spon. breathed MV

No

spontaneous

breathing

Starting

spontaneous

breathing

Sufficient

spontaneous

breathing

D-75-28-2014

Fig. 1 (from 100% ventilation to 100% spontaneous breathing)

Fig. 2 (VC-MMV + AF with mandatory breath and spontaneous breathing)

t

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ATC

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ATC

Automatic Tube Compensation

–– ensures that the set airway pressure is also obtained in the trachea

–– is calculated and displayed based on a mathematical tube model,

the set tube type and the tube’s internal diameter (tracheal pressure)

–– can be activated for any mode of ventilation

The tube as an artificial resistance in the airway is the main reason for

increased breathing effort by the patient. The automatic tube

compensation is a supplement for all ventilation modes and enables the

precise compensation of this increased work of breathing, with easy

setting options. The patient’s inspiratory effort should feel as if they are

not intubated. A gas flow through the tube leads to a pressure difference

(ΔP tube) between the start and end of the tube [Fig. 1]. This pressure

difference should stimulate the respiratory muscles in the form of

increased negative pressure in the lungs. However, the increased work

of breathing can be compensated by increasing the pressure in front of

the tube by precisely the amount of the pressure difference. This means

that the pressure in front of the tube also needs to be continuously

adapted to the relevant gas flow. The actual pressure difference is

calculated based on the gas flow measured by the ventilator. Automatic

tube compensation can be activated for any mode of ventilation. The tube

dimensions must first be set. The level of compensation (generally 100%)

can be used to fine-tune the settings for the relevant tube in order to

prevent overcompensation. The length of the tube does not have a

significant influence on the tube resistances, even for very short tubes,

and is not set.

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ATC

The tube compensation is applied for both inspiration as well as

expiration. [see Fig. 3] If necessary for expiratory compensation, the

pressure in the tube system is reduced to no less than the ambient

pressure in order to facilitate the patient’s exhalation. The control

ensures that the tracheal pressure does not fall below the set CPAP

pressure.

without ATC

with ATC

Paw

D-7480-2014

P trachea

P mus

Paw

P tube

P trachea

P tube

P mus

Fig. 1 Without ATC, the patient needs to apply the ΔP tube.

With ATC, the ventilator generates precisely this ΔP tube and provides relief for the

patient.

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ATC

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delta

P tube

25

Pressure difference between

the tube connector and the

tube tip for a 7.5 mm tube

20

15

10

PS undercompensation

D-7481-2014

5

PS overcompensation

10

20

PS pressure

30

40

50

60

70

Flow

80

Fig. 2 Set pressure support (PS) compared to pressure support required in principle (blue

line) for tube compensation.

Paw

Ptrach

Pressure at the Y-piece

Tracheal pressure

PEEP

Flow

t

t

Fig. 3 Pressure profile for tube compensation during inspiration and expiration.

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SPN-PPS

SPN-PPS

Spontaneous – Proportional Pressure Support

–– applies patient-triggered pressure support in proportion to the patient’s

inspiratory effort

–– the level of support can be set separately for restrictive or obstructive

work of breathing

For SPN-PPS, the pressure support should ideally be proportional to the

patient’s inspiratory effort. If the patient’s breathing is shallow, little

support is provided. More support is applied for a deep breath. The

absolute amount of support depends on both the Flow Assist and

Volume Assist parameter settings as well as the patient. The two types of

pressure support, pressure support proportional to volume (Volume

Assist) and pressure support proportional to flow (Flow Assist) [Fig. 1]

can be combined. If set correctly, only the illness-related higher work of

breathing is continuously adapted and compensated – the physiological

work of breathing continues to be provided by the patient alone. Flow

Assist helps overcome the resistance (R) and the pressure support is

proportional to the flow. In contrast, Volume Assist compensates the

elastic resistance (C) caused by reduced elasticity of the lungs. The

pressure support is proportional to the tidal volume. The relationship

between the inspiratory effort and the pressure support remains

constant for the same settings, while the pressure support varies for

every breath. If no spontaneous breathing is detected, the mechanical

support also ceases. Adequate apnoea and minute volume monitoring

must therefore be in place.

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SPN-PPS

Flow Assist: pressure profile proportional

to the flow

Vol. Assist: inspiration pressure profile

proportional to the tidal volume VT

Flow

Flow

VT

VT

t

t

Paw

t

Paw

PEEP

Inhalation

Exhalation

PEEP

t

D-7526-2014

Fig. 1 Rules for Flow and Volume Assist

Fig. 2 SPN-PPS, typical pressure and flow graph

Inhalation

Exhalation

t

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SMARTCARE®

SmartCare®

–– is an automatic clinical protocol

–– reduces the pressure support based on the averaged measured values

for the spontaneous respiratory rate, the tidal volume and the ETCO2

until the lowest possible level is reached

–– can reduce the overall ventilation period by up to 33% and the stay in

the intensive care unit by up to 20%1)

SmartCare®/PS is an automated clinical protocol, which was designed

to stabilise a patient’s spontaneous breathing in a “comfort zone” and

automatically reduce the respiratory support. The patient should be ready

for weaning, i.e. haemodynamically stable, and display adequate oxygenation and spontaneous breathing. SmartCare/PS attempts to keep the

patient within the “normal ventilation” range and places the patient back

“on the right track” in the event of a contrasting diagnosis. The patient’s

ventilation status is classified into eight different diagnoses and defined

measures are taken in order to bring the patient back to the “normal

ventilation” range, also referred to as the “respiratory comfort zone”. The

three key criteria are the spontaneous respiratory rate

(RRspon), tidal volume (VT) and endtidal CO2 (ETCO2) [ventilator’s

measured values]. This protocol is active during all phases of

a SmartCare/PS session. In addition, the pressure support level is

gradually reduced during the “adapt” phase, while continuous checks

confirm whether the patient is able to tolerate the new level. If this is the

case, the pressure support is reduced further, if not, it is increased back

to a level that is appropriate for the patient. The optimal case involves the

gradual and direct reduction of the pressure support until the lowest

level is reached.

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SMARTCARE®

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1) Lellouche, F. et al.; a Multicenter Randomized Trial of Computer-driven Protocolized Weaning from Mechanical

Ventilation. am J Respir Crit Care Med Vol 174. pp 894 -900, 2006 – The results are based on a randomised

study in several European hospitals with 144 patients who displayed a stable ventilation situation, a stable haemodynamic and neurological status and no ARDS prior to their initial weaning.

55 mmHg

Tachypnoe

Severe tachypnoea

Insufficient

ventilation

Hypoventilation

Normal

ventilation

Hyperventilation

20 mmHg

D-7482-2014

Unexplained

hyperventilation

ETCO2

35 bpm

30 bpm

15 bpm

fspn

Fig. 1 Diagnostics diagram based on the key criteria

Initiate

Adapt

Monitor

Maintain

No

Extubate?

Quickest path

D-7483-2014

Regression in case of permanent instabilities

Automatic protocol

User measures

Fig. 2 Functional principle – individual phases during SmartCare®

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SMARTCARE®

PREREQUISITES

It is important to choose the “right” patient. SmartCare/PS is ideal

for patients with primary restrictive problems and longer expected

weaning times. SmartCare/PS does not replace the clinician. The

advantage of SmartCare/PS is its ability to continuously monitor

the patient making appropriate changes to pressure support much

more often than this would be possible manually. Prior to starting

weaning with SmartCare/PS, the patient must be haemodynamically

stable, be ventilated with SPNCPAP/PS (optionally with ATC), and

the set PEEP must be ≤ 20 mbar.

QUICK START

1.PATIENT

a) Set the patient’s height; this

calculates the IBW and the

lower limit for the tidal volume

(Vt) can be derived from it.

b) Set the maximum permissible

PEEP value and the

inspiratory oxygen

concentration for the start of

the spontaneous breathing

test.

SmartCare/PS can be started with any PEEP setting between

0 and 20 mbar and with any selected FiO2 concentration. The

spontaneous breathing test starts once the target support pressure

(∆Psupp target, see 2.) has been reached and the PEEP and FiO2

values set by the user have been reached or undercut.

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SMARTCARE®

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2. A

 CCESS TO THE AIRWAY

These settings define the target

support pressure at which the

spontaneous breathing test

starts (provided that PEEP and

FiO2 are also below the set

values – see 1). The following

table shows the dependencies

of the different settings:

Access to the airway,

type of humidification

ΔPsupp

target

IBW

Patient tracheostomised, active/no

humidification, ATC OFF

Patient endotracheally intubated, active/no

humidification, ATC OFF

Patient tracheostomised, HME filter,

ATC OFF

Patient endotracheally intubated, HME filter,

ATC OFF

Patient tracheostomised or endotracheally

intubated, active humidification, ATC ON

Patient tracheostimised or endotracheally

intubated, HME filter, ATC ON

5 mbar

≥ 36 kg

7 mbar

≥ 36 kg

9 mbar

≥ 36 kg

10 mbar

≥ 36 kg

0 mbar

≥ 36 kg

5 mbar

≥ 36 kg

If the therapists prefers to set target values for the pressure support

that differ from those that are shown in the table, he can enter

“wrong” specifications (e.g., tracheostomised rather than intubated)

to generate a different target value for the pressure support.

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SMARTCARE®

3. MEDICAL HISTORY

Selection of COPD and

neurological disorder for the

automatic adaptation of the

upper limit for etCO2 and the

respiratory rate (RR)

The COPD “Yes” setting means that the SmartCare/PS continues

to accept etCO2 values less than or equal to 64 mmHg (8.5Kpa) as

normal. This may also be helpful for patients with permissive

hypercapnia. The neurological disorder “Yes” setting means that the

SmartCare/PS continues to accept respiratory rates of up to 34/min

as normal. This may also be helpful for patients with higher

respiratory drive.

4. NIGHT’S REST

No active weaning takes place

during the selected period, i.e.,

SmartCare/PS maintains the

pressure support it had reached

prior to night rest commencing.

However, SmartCare/PS will

increase the pressure support if

the patients condition

deteriorates.

Night’s rest can also be set in order to give the patient a break

from weaning. It is also possible to set or switch off night’s rest

during an ongoing session.

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SMARTCARE®

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5. C HANGE THE GUIDELINE

Extended functionality for

customising the weaning

protocol.

This lets you define an individual respiratory comfort zone for the

patient. The set values of the medical history (see 3.) have no impact

if the guideline is changed.

6. START PATIENT SESSION

Flow measurement, CO2

measurement and apnoea

ventilation must be switched on.

The following icon appears in the header bar once the SmartCare/

PS session has successfully started

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SMARTCARE®

TIPS AND TRICKS

– Alarm limits must generally be set above and below the SmartCare/PS limit values (see instructions for use).

– An apnoea alarm leads to the unwanted cancellation of the

SmartCare/PS session.

Therefore, possible disconnections should be shorter than the

set apnoea time.

– A functioning CO2 measurement is required for SmartCare/PS

(position the CO2 cuvette to prevent the accumulation of

moisture or secretion, e.g., between the Y-piece and the HME

filter or vertically, pointing upward).

– Configure a specific SmartCare/PS view with the required

specific information (SmartCare/PS values, status and trends).

– Use the O2/suction function to perform a suction manoeuvre.

This pauses the SmartCare/PS and gives the patient time to

recover.

– The SmartCare/PS is suitable for adult and paediatric patients.

More information: www.draeger.com/smartcare

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P0.1 – OCCLUSION PRESSURE MEASUREMENT

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P0.1 – Occlusion Pressure Measurement

–– occlusion pressure measurement at the start of inspiration

–– is a measure of the neuromuscular respiratory drive1)

During a P0.1 manoeuvre, the ventilator closes the inspiratory valve for a

brief period after expiration and measures the airway pressure generated

over 100 ms by the inspiratory effort [Fig. 1]. The pressure is not

influenced by physiological compensation reactions, e.g. reflective

respiratory arrest or increased drive, within 100 ms. This pressure also

fundamentally depends on the muscular strength of the diaphragm. As a

result, the negative mouth pressure P0.1 after 0.1 seconds is a measure

of the neuromuscular respiratory drive1). The ventilator displays the value

of the measured pressure difference [Fig. 2]. For patients with healthy

lungs and calm breathing, the P.01 value is between 3 and 4 mbar (3 to

4 cmH2O). A higher P0.1 value reflects a high respiratory drive, which can

only be maintained for a limited time. P0.1 values over 6 mbar

(6 cmH2O), e.g. for a COPD patient, reflect imminent fatigue (respiratory

muscle fatigue). As shown in figure 1, the 100 ms starts once negative

pressure of -0.5 mbar (–0.5 cmH2O) is measured during the inspiratory

effort under PEEP/CPAP. The second pressure value is determined

after the 100 ms have elapsed. The inspiratory valve is simultaneously

opened. The patient can then breathe normally once again. The pressure

difference value “P2 - P1” defines the occlusion pressure P0.1.

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P0.1 – OCCLUSION PRESSURE MEASUREMENT

Normal value1):

P0.1 = 1 up to 4 mbar

P0.1 > 6 mbar, indication of imminent respiratory muscle fatigue,

high probability of weaning failure.

1) Oczenski W (ed). Atmen-Atemhilfen. 8. Auflage 2008

Tobin MJ (ed). Principles and Practice of Mechanical ventilation. Second Edition. McGraw-Hill, New York,

2006, Sasson CSH, et al. Airway Occlusion Pressure : An important Indicator for successful weaning in

patients with Chronic obstructive pulmonary disease. AM Respir Dis. 1987;135:107-113

Paw

PEEP

–0.5 mbar

(–0.5cm H2O)

Inspiratory valve

closed

100m s

Inspiratory valve open

t

P1

P0.1

P2

D-7524-2014

Fig. 1 Functional principle of the P0.1 measurement

Fig. 2 Screen layout during a P0.1 measurement

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LEAK COMPENSATION

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Leak Compensation

–– leaks are compensated for in volume- and pressure-controlled

ventilation

–– the inspiratory flow trigger threshold and the cancellation criteria for

pressure support are adapted automatically

–– leak compensation displays all the volume and flow measured values

with leak compensation

The ventilator determines the difference between the dosed inspiratory

flow and the flow measured during expiration. This difference defines the

size of the leak and is displayed as the leak minute volume MVleak and

the relative leak % (MVleak to MV). The leak correction calculation takes

the pressures in the breathing circuit into account. The percentage

volume loss during inspiration is greater than the loss during expiration,

as the pressure is higher during inspiration. The leak minute volume MVleak also considers inspiratory leaks. During volume-controlled

ventilation, the ventilator provides additional volume to compensate for

the leak. The ventilator compensates volume losses up to 100% of the set

tidal volume Vt. Measured volume and flow values are displayed with leak

compensation. An exception is the measured expiratory minute volume

as well as measured values marked as inspiratory or expiratory, such as

VTi and VTe. The inspiratory flow trigger threshold and the cancellation

criterion are applied to the leak-corrected flow, while both settings are

continuously adapted with respect to the leak.

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LEAK COMPENSATION

Vt

Tidal volume, leak-corrected

Vti

Inspiratory tidal volume, without leak-correction

Vte

Expiratory tidal volume, without leak-correction

Mv

Minute volume

Mvi

Inspiratory Minute volume, without leak-corrected

Mve

Expiratory Minute volume, total, without leak-corrected

Mvleak Leak Minute volume

(based on the medium pressure Paverage)