Patient-Ventilator Asynchrony ΠΡΙΝΙΑΝΑΚΗΣ ΓΕΩΡΓΙΟΣ ΔΙΕΥΘΥΝΤΗΣ ΕΣΥ - ΜΕΘ ΠΑΓΝΗ ΗΡΑΚΛΕΙΟΥ

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1 Patient-Ventilator Asynchrony ΠΡΙΝΙΑΝΑΚΗΣ ΓΕΩΡΓΙΟΣ ΔΙΕΥΘΥΝΤΗΣ ΕΣΥ - ΜΕΘ ΠΑΓΝΗ ΗΡΑΚΛΕΙΟΥ Πρόγραμμα Μεταπτυχιακών Σπουδών «Μονάδες Εντατικής Θεραπείας» 31/1/217

2 ΥΠΟΒΟΗΘΟΥΜΕΝΟΣ ΜΗΧΑΝΙΚΟΣ ΑΕΡΙΣΜΟΣ PT= Paw +Pmus = V x Rrs + V x Ers + = V x Rrs + V x Ers ΑΝΑΠΝΕΥΣΤΗΡΑΣ + ΑΣΘΕΝΗΣ = V x Rrs + V x Ers

3 Patient brain Synchrony between brains Physician brain Pmus Paw Synchrony between patient and ventilator

4 Equation of motion Mechanical ventilation Volume control P ventilator + Pmus = V xrs + VxErs Dependent variable Independent variables

5 Volume control Inspiratory phase Pmus (cmh 2 O) Paw (cmh 2 O) Flow (l/sec) o identify non-synchrony phenomena observe Paw 2 1,5 1,5,1,2,3,4,5 -, Passive Active,1,2,3,4, ,1,2,3,4, Independent variable Dependent variable P ventilator + Pmus = V xrs + VxErs Time (sec)

6 Equation of motion Mechanical ventilation Pressure control P ventilator + Pmus = V xrs + VxErs Independent variable Dependent variables

7 Pmus (cmh 2 O) Volume (l) Flow (l/sec) Paw (cmh 2 O) Pressure control/support Inspiratory phase Independent variable -2,2,4,6,8 1 1,2 o identify non-synchrony phenomena observe flow (mainly) and volume Active Passive 1,5 1,5,2,4,6,8 1 1,2 -,5,6-1,5,4,3,2,1,2,4,6,8 1 1,2 Dependent variable Dependent variable ,2,4,6,8 1 1, Time (sec)

8 Μηχανικός εισπνευστικός χρόνος και Νευρικός εισπνευστικός χρόνος 2 Paw Αρχή και τέλος της μηχανικής εισπνευστικής προσπάθειας Flow τ ι m τ ι n Αρχή και τέλος της νευρικής εισπνευστικής προσπάθειας 12 Pmus Time (sec)

9 ΑΝΑΓΝΩΡΙΣΗ ΦΑΙΝΟΜΕΝΩΝ ΑΠΟΣΥΓΧΡΟΝΙΣΜΟΥ ΑΣΘΕΝΗ ΑΝΑΠΝΕΥΣΤΗΡΑ ΑΝΤΙΜΕΤΩΠΙΣΗ ΦΑΙΝΟΜΕΝΩΝ ΑΠΟΣΥΓΧΡΟΝΙΣΜΟΥ ΑΣΘΕΝΗ ΑΝΑΠΝΕΥΣΤΗΡΑ

10 Επιμέρους φάσεις αναπνοής Trigger Cycling Pressurization pressurization Cycling off trigger

11 Asynchrony in Triggering INEFFECTIVE EFFORT (Αναποτελεσματική προσπάθεια) AUTOTRIGGERING (Αυτοπυροδότηση) DOUBLE TRIGGERING (Διπλή πυροδότηση)

12 DYNAMIC HYPERINFLATION cmh 2 O V Expiratory flow FRC Vt +5 Paw Pmus

13 cmh 2 O Flow = ΔP/R Flow Expiratory flow Flow = (Pel-)/R Pmus Flow = (Pel--Pmus)/R Pmus Pel

14 Pes V T Paw Flow

15 Ineffective effort (Αναποτελεσματική προσπάθεια) Frequency Ventilator < Frequency patient

16 Flow = ΔP/R Flow Pmus Flow = (Pel- -Pmus )/R

17 MISSING EFFORT Μείωση εκπνευστικής ροής Πτώση Paw

18 Pes V T Paw Flow

19 Pes (cmh 2 O) Paw (cmh 2 O) Flow (l/sec),8,6,4,2-2 -, ,4 -,6 -, Vent. rate = 12 b/mi Fr = 33 b/min Time (sec) 5 sec Georgopoulos et al. Intensive Care Med 26

20 Flow (l/sec) Pes (cmh 2 O) Ventilator pressure driving pressure for V I driving pressure for V E,8,6,4,2 Pmus I Pel Pmus I -,2 -,4 -,6 -,8 Rapid decrease in V E Rapid decrease in V E Time (sec) 5 sec

21 Be careful! These are not ineffective efforts Pmus E Pel

22 Causes of Ineffective Effort

23 Prevalence of asynchrony 62 patients (26% with COPD) intubated for acute respiratory failure. Fifty-one patients (82%) were ventilated with pressure support, and 11 (18%) with CMV. % 13 Ineffective effort Expiration / Inspiration Thille et al ICM 26

24 AUTOTRIGGERING Ο αναπνευστήρας πυροδοτείται αυτόματα χωρίς αναπνευστική προσπάθεια από τον ασθενή Frequency Ventilator > Frequency patient

25 AUTOTRIGGERING Flow V T Αύξηση του triggering Trigger:.5l/m Trigger: 2.5 l/m Paw Καρδιακή ώση Pes f:8/min time

26 AUTOTRIGGERING Pes 3 2 Paw Flow

27 3 2 Flow (l/sec) Paw (cmh 2 O) Pes (cmh 2 O) Absence of Paw/flow distortio before triggering 1 1,2,8,4, -,4 -, No dynamic hyperinflation Alveolar pressure distortion Triggering sensitivity Patients at risk of autotriggering 1) drive and RR 2) time constant (RxC) 3) SV and cardiac filling press Imanaka et al. Crit Care Med. 2;28:42 Prinianakis et al. Intensive Care Med 23;29: Time (sec) Leaks in the circuit Carteaux et al. Chest. 212;142(2):

28 Causes of ventilator autotriggering

29 Double triggering-διπλή διέγερση Μια προσπάθεια του ασθενή πυροδοτεί δύο προσπάθειες του αναπνευστήρα

30 DOUBLE TRIGGER Flow Paw Pga Pes Pdi

31 Causes of double trigger High elastic recoil Low expiratory resistance Low tidal volume Long neural inspiratory time High respiratory drive Low threshold of trigger low time constant

32 Pressurization phase

33 Volume control Negative relationship between Paw and Pmus I P ventilator + Pmus = V xrs + VxE Patient s effort Nilsestuen and Hargett Respir Care 25

34 Assist volume Large drop in Pes (strong effort) Demands are not met Delayed opening (Expiratory asynchrony PEEP

35 Paw Pt. no. 1 Pt. no Flow Pdi -,5,5 1 1,5 2 2,5 3 1,5 -,5,5 1 1,5 2 2,5 3 -, Demands are met -,5,5 1 1,5 2 2, ,2,2,4,6,8 1 1,2 1,4,4,2 -,2,2,4,6,8 1 1,2 1,4 -,2 -,4 -, Demands may or may not be met Look for clinical Signs of high drive -,2,2,4,6,8 1 1,2 1,4-4

36 Be careful! These are not ineffective efforts Expiratory muscle activity toward the end of expiration may indicate unme demands

37 Breath stacking may also indicate unmet demands 15 cmh 2 O drop in Pes Kondili et al. Br J Anaesth 23;91:16 Beitler et al. Intensive Care Medicine 216

38 Inspiratory rise time (pressurisation rate-ramp) Paw Fast IRT Paw Slow IRT 15 IPAP(PS) 15 IPAP(PS) 5 PEEP 5 PEEP t IRT:,5 sec (9%) IRT:,2 sec (5%) t

39 Inspiratory rise time Fast IRT, less work of breathing Prinianakis G,. Eur Respir J 24

40 EXPIRATORY ASYNCHRONY Αποσυγχρονισμός κατά την μετάβαση από την εισπνοή στην εκπνοή

41 Expiratory asynchrony is the inability of the ventilator to synchronize the end of mechanical inflation with the end of neural inspiration Types of Expiratory asynchrony Premature opening Delayed opening Paw or V I Pmus Paw or V I Pmus

42 EXPIRATORY ASYNCHRONY T I neural > T I mechanical

43 Pmus (cmh 2 O) Paw (cmh 2 O) Flow (l/sec),2 -,2 -,6-1 -1,4-1, Passive expiration V E Pel(t) = ΔV(t)xErs Pmus I (t) Risk of double triggering (during the delay time Pmus may trigger the ventilator again) 1 5 Valve opens,2,4,6,8 1 Expiratory time (sec)

44 Νευρικός εισπνευστικός χρόνος > Μηχανικός εισπνευστικός χρόνος Flow Τέλος μηχανικής εισπνευστικής προσπάθειας Paw Pga Pes Pdi Τέλος νευρικής εισπνευστικής προσπάθειας

45 Expiratory asynchrony Be careful!! These are not ineffective efforts Premature opening Paw or V I Pmus Flow Paw Pga Pes Pdi Georgopoulos et al. Intensive Care Med 26;32:34-47

46 Expiratory Asynchrony) Καθυστερημένη μετάβαση στην εκπνοή (Delayed Termination). Ο μηχανικός εισπνευστικός είναι μεγαλύτερος από τον νευρικό εισπνευστικό χρόνο. Τ I mechanic > T I neural

47 Νευρικός εισπνευστικός χρόνος < Μηχανικός εισπνευστικός χρόνος 2 Paw Τέλος μηχανικής εισπνευστικής προσπάθειας Flow Τέλος νευρικής εισπνευστικής προσπάθειας Pmus Time (sec)

48 Τελικοεισπνευστική αύξηση της Paw (φαινόμενο εκπνευστικής ασυγχρονίας)

49 Intensive Care Med 27

50 Types of Expiratory asynchrony Premature opening Delayed opening Paw or V I Pmus Paw or V I Pmus Restrictive lung disease (ARDS)/ Premature opening Risk of double triggering Obstructive lung disease (COPD, Asthma)/ Delayed opening Risk of ineffective efforts

51 The ventilator breath triggers inspiratory effort (vagal feedback cortical influence) Entrainment (Reverse triggering) implies a resetting of the respiratory rhythm such that a fixed temporal relationship exists between the onset of inspiratory activity and the onset of a mechanical breath. Simon et al. J Appl Physiol 2 Simon et al. Am J Respir Crit Care Med 1999 Georgopoulos D. Principles and Practice of Mechanical Ventilation 213 (ed. Tobin)

52 1:1 2:1 3:1 Akoumianaki et al. Chest. 213;143(4):

53 Improvement of patient ventilator asynhronies

54 ΑΝΤΙΜΕΤΩΠΙΣΗ Decrease the dynamic hyperinflation low tidal volume, long expiratory time, decrease the respiratory resistance Increase the power of Pmus decrease in sedation level Application of external PEEP Decrease the threshold for triggering Georgopoulos et al. Intensive Care Med (26)

55 flow Trigger with method of Flow shape signal t Pmus

56 Flow shape signal trigger Fig. 24 Flow shape signal and ineffective efforts 12ms flow-waveform method 2ms flow triggering Flow trigger Ιn the presence of dynamic hyperinflation: the flow-waveform method of triggering compared to flow triggering decreases 1) the triggering delay and 2) the number of ineffective efforts Prinianakis et al. ICM 23

57 Neurally Adjusted Ventilatory Assist Flow Paw V T Pdi Colombo et al. ICM 28

58 Ventilator rate (cycles/min) In the PS group, from a total of 696 measurements, 95 (13.6%) revealed a difference between patients breathing frequency and ventilator rate. In the PAV+ group, from a total of 744 measurements, 21 (2.8%) revealed a difference between patients breathing frequency and ventilator rate PS (696 measurements) PAV+ (744 measurements) Patients breathing frequency (breaths/min) Xirouchaki et al. Intensive Care Med 28

59 Optimal Pressure Support and TI Thille et al. Intensive Care Med 26.

60 Expiratory trigger Peak flow 1% Flow F L O W 75% 25% ΕΙΣΠΝΟΗ 75% Time ΕΙΣΠΝΟΗ 25%

61 Σε ασθενείς με αυξημένες αντιστάσεις αεραγωγών Υψηλότερο flow cycle συνήθως 4% (βραχύτερη εισπνοή) Σε ασθενείς με μειωμένη compliance Χαμηλότερο flow cycle (1%) (παράταση εισπνοής)

62 9 vs. 2 breaths/min, p<.5 Tassaux et al Am J Respir Crit Care Med 25

63 Patient- Ventilator Asynchrony and Outcome

64 ASYNCHRONY INDEX An asynchrony index > 1% was considered severe

65 Factors to Consider in Determining How Often Patient- Ventilator Asynchrony Occurs Timing of observations Duration of observations Method of detection Esophageal pressure Electrical activity of the diaphragm Waveform analysis Type of asynchrony Patient population Type of mechanical ventilation Triggering method Cycling method Degree of ventilatory support Blanch et al. ICM 215 Additional factors Sedation Epstein et al. Respir Care 211

66 Asynchrony Index and outcome IEs or asynchronies index greater than 1 % has been used. Using this cut-off value, two of the studies showed an association with increased duration of mechanical ventilation but not mortality, while the other study found higher ICU mortality Thille et al ICM 26 de Wit et al. CCM 29 Blanch et al. ICM 215

67 p <.4 De Wit et al. CCM 29

68 Asynchrony Index and outcome 7 p=.1 P= p> p>.5 2 p>.5 33 LOS Reintubation Tracheostomy ICU Mortality Hospital Mortality AI>1% AI<1% Blanch et al. ICM 215

69 Clusters of ineffective efforts during mechanical ventilation: impact on outcome Clusters of ineffective efforts :Events of IEs were defined as periods of time containing more than 3 IEs in a 3-min period 11 patients were included in the analysis 2931 h of assisted mechanical ventilation, and 4,456,537 breaths. median IEs index was 2.43 (IQR ) IEs index >1 % was found in 13 patients (12 %) Vaporidi et al. Intensive Care Med 216

70 Events of ineffective efforts The main findings of this study in critically ill patients were: 1) the IEs index>1 %, had no correlation with patient outcome; 2) the presence of events of IEs was associated with longer duration of mechanical ventilation and higher hospital mortality.

71 Έργο αναπνευστικών μυών Εξατομίκευση του μηχανικού αερισμού δύσπνοια ταχύπνοια υπερκαπνία Υπερδιάταση PEEPi Missing effort Ασυγχρονία εκπνοής Ελλιπής υποστήριξη Βέλτιστες ρυθμίσεις υποστήριξης Υπερβολική υποστήριξη Πίεση υποστήριξης

72 Patient brain Dyssynchrony between brains Physician brain Education Pmus Paw Dyssynchrony between patient and ventilator