Ventilator Dyssynchrony - Recognition, implications, and management

Transcription

1 Ventilator Dyssynchrony - Recognition, implications, and management Gavin M Joynt Dept of Anaesthesia & Intensive Care The Chinese University of Hong Kong

2 Dyssynchrony Uncoupling of mechanical delivered breath and neural respiratory effort

3 Patient-ventilator Dyssynchrony Consequences Increased WOB Discomfort Fatigue (physical and mental) Subtle and frequently unsuspected Gilstrap D, MacIntyre N. Am J Respir Crit Care Med 2013;188:1058

4 How common is dyssynchony? ACV PSV Asynchronies 4.3± ±3.8 Ineffective triggering Doubletriggering 3.0± ± ± ±0.4 Thille AW et al. Intensive Care Med, 2006;32:

5 Duration of mechanical ventilation Duration of mechanical ventilation (days) P= Asynchrony index<10% Asynchrony index 10% Thille AW et al. Intensive Care Med, 2006;32:

6 Outcomes Percentage P=0.007 Asynchrony index<10% Asynchrony index 10% Tracheostomy Mortality Thille AW et al. Intensive Care Med, 2006;32:

7 Dyssychrony diagnosis Principles of recognition Look at the patient Ventilator graphics Types Expiratory-inspiratory cycling (Trigger initiation) Inspiratory Inspiratory-expiratory cycling

8 Auto-triggering Pressure Normal trigger Auto-trigger Time PEEP Trigger level Triggering in the absence of inspiratory muscle contraction

9 Auto-triggering Chui PT, Joynt GM, Oh TE. Anaesthesia 1995;50:978

10 Auto-triggering - solutions Check circuit and eliminate the leak/ secretions causing oscillations Decrease trigger sensitivity Reduce or eliminate PEEP Change mode of triggering

11 Trigger delay Pressure Flow Excessive delay between insp. muscle contraction and delivery

12 Ineffective triggering Pressure Flow Discomfort and increased work of breathing

13 Trigger delay & ineffective efforts Patient factors Dynamic hyperinflation Low respiratory drive (drugs) Weak inspiratory muscles Ventilator factors Excessively high tidal volumes Incorrect trigger sensitivity setting Malfunction (sticky valves) Important others Partially blocked ETT/circuit component

14 Dynamic hyperinflation End-expiration Early inspiration

15 Dynamic hyperinflation End-expiration with PEEPi=6 Early inspiration

16 Auto-PEEP and triggering Chui PT, Joynt GM, Oh TE. Anaesthesia 1995;50:978

17 Trigger delay and Ineffective efforts Ventilator factors High level of pressure support High tidal volume Solution Decrease hyperinflation

18 Dynamic hyperinflation Patient factors Expiratory airway obstruction (COPD/Asthma) Solution Decrease hyperinflation Application of external PEEP

19 Dynamic hyperinflation End-expiration with PEEPi=6 Early inspiration

20 Dynamic hyperinflation End-expiration with PEEPi=6 Early inspiration with PEEPe=6

21 Setting PEEPe ~70% of PEEPi Titrate against patient response Audible delay Subcostal recession Accessory muscle use

22 Inspiratory-expiratory cycling Premature cycling Delayed cycling

23 Premature inspiratory - expiratory cycling Flow Ventilator has switched to expiration (while the patient is still breathing in)

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25 Delayed inspiratory - expiratory cycling Pressure Flow Mechanical inspiration continues into neural expiration

26 Treatment summary Ventilator settings Adjusting flow rates, rise times, cycle times, cycle flow settings, tidal volumes, driving pressure settings Patient factors Bronchodilators Increase or decrease sedation/analgesia Communication

27 Easier Way Processed diaphragmatic electrical signal Neural activity Oesophageal pressure monitoring Pleural pressure as a measure of respiratory muscle activity

28 Δ Pressure Δ Flow Neuro-mechanical coupling Neuro-coupling Edi NAVA

29 Reducing dyssynchrony with NAVA? Improved trigger timing Eliminate the delay between neural trigger and ventilator activation Fewer wasted respiratory efforts Pressure delivery pattern matched to demand

30 Terzi N et al. Critical Care 2012;16: 225

31 Terzi N et al. Critical Care 2012;16: 225

32 Li AMMY et al. Manuscript in preparation

33 ICU mortality (%) N=100 p= AI 10% AI<10% Li AMMY et al. Manuscript in preparation

34 Asynchrony index (%) N=22 Crossover p= PS1 NAVA PS2 Piquilloud L et al. Intensive Care Med, 2011; 37:

35 Demoule et al. Intensive Care Med 2016; 42:1723

36 Demoule et al. Intensive Care Med 2016; 42:1723

37 Conclusions Dyssynchrony is common Associated with prolonged weaning mortality Diagnosed from waveform analysis & examination of patient Treatment is multi-modal NAVA may help reduce asynchrony

38 Brander L et al. Chest, 2009; 135(3):

39 Hering-Breuer reflex VT (ml/kg) lean predicted Reduces risk of auto-peep Proportionality factor/edi

40 Acknowledgenemts Dr Alex Li Prof Charles Gomersall