Ventilation Mini Manual - Mode and Function Guide March 2015

TABLE OF CONTENTS

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Table of contents PC-BIPAP vs. PC-AC Pressure Control – Biphasic Positive Airway Pressure vs. Pressure Control – Assist Control PC-APRV (Pressure Control – Airway Pressure Release Ventilation) VC-MMV + AutoFlow Volume Control – Mandatory Minute Volume + AutoFlow ATC – Automatic Tube Compensation SPN-PPS (Proportional Pressure Support) SmartCare® P0.1 – Occlusion Pressure Measurement Leak Compensation NIV (Non-invasive Ventilation) Variable PS (Variable Pressure Support) PEEPi (Intrinsic PEEP / AutoPEEP) Low Flow Manoeuvre Ventilation Terms Notes

04 - 06 07 - 08 09 - 10 11 - 13 14 - 15 16 - 22 23 - 24 25 - 27 28 - 30 31 - 33 34 - 36 37 - 38 39 - 40 41 - 42

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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

PC-BIPAP VS. PC-AC

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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

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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)

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.

PC-APRV

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

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

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

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

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

t

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

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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.

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

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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

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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.

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

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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

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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.

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.

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