Αποδέσμευση από τον αναπνευστήρα. Weaning

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1 Αποδέσμευση από τον αναπνευστήρα Weaning Θεόδωρος Βασιλακόπουλος Καθηγητής Πνευμονολογίας-Εντατικής Θεραπείας Εθνικό & Καποδιστριακό Πανεπιστήμιο Αθηνών Νοσοκομείο «ο Ευαγγελισμός» Adjunct Professor, McGill University, Montreal, Canada Γενικός Γραμματέας Ελληνικής Πνευμονολογικής Εταιρείας

2 TIME SPENT ON MECHANICAL VENTILATION Onset of weaning MV discontinuation criteria met Full support Weaning time Initiation of MV Discontinuation of MV 2005 P. Navalesi (Pavia, Italy)

3 Ventilator-Induced Diaphragmatic Dysfunction Tobin MJ. N Engl J Med 1994

4 MV ONSET MV DISCONTINUATION MV ONSET MV DISCONTINUATION MV ONSET WEANING FAILURE MV DISCONTINUATION 2005 P. Navalesi (Pavia, Italy)

5 471 PATIENTS SELF-EXTUBATED WHILE ON MECHANICAL VENTIALTION 242 REINTUBATED 49% 51% 229 NON REINTUBATED (i.e. no need for MV)

6 SELF EXTUBATION IN 75 PATIENTS DURING FULL VENTILATORY SUPPORT 42 PATIENTS DURING WEANING 33 PATIENTS 77% 31% 23% 69% Epstein SK J at all. Am J Respir Crit Care Med: 2000; 161:

7 The process of Weaning Eur Respir J 2007;29:

8 CRITERIA FOR WEANING ONSET Objective measurements Adequate oxygenation (PaO 2 >60 mmhg, PEEP<5-10 cmh 2 O, FiO 2 <0.4) Stable cardiovascular system (HR <140, stable BP) Afebrile (<38 ) No significant respiratory acidosis Adequate hemoglobin (Hb>8-10g/dl) Adequate mentation (GCS>13, no continuous sedative infusion) Stable metabolic status (acceptable electrolytes) Subjective clinical assessments Resolution of disease acute phase (physician believes discontinuation possible) Collective Task Force (ACCP, AARC, ACCCM) Chest: 2001; 120 (6): 375s-395s

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10 Mechanical Ventilation Assessment of Weaning Readiness A method for Screening (Spontaneous Breathing Trial = SBT) A method for Weaning Difficult-to-wean patients (i.e., patients who fail SBT)

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12 Assessment of readiness Weaning indices

13 VT (ml) Frequency (b/min) Rapid Shallow Breathing Index (f/vt) f/vt Minutes Tobin et al: Am Rev Respir Dis 1986; 134: 1111 Yang and Tobin N Engl J Med 1991

14 15 x mpaw/mip + 3 x RSBI /100 5 < 1 15 x mpaw/mip + 3 x RSBI /100 <

15 ideal index real index

16 Methods for Screening: Spontaneous Breathing Trial

17 What type of SBT to test readiness? T-piece PSV Success Failure Success Failure 192 (78%) (86%) 33 Reintubation Reintubation (18.7%) (18.5%) Esteban et al. Am J Respir Crit Care Med 1997

18 What is the optimal duration of screening trial (SBT)?

19 How long should the T piece SBT be? 526 patients MV > 48 hrs T-piece 30 min 270 T-piece 120 min 256 Success Failure Success Failure 237 (88%) (84%) 40 Reintubation Reintubation (13.5%) (13.4%) Esteban et al. Am J Respir Crit Care Med 1999; 159: 512

20 How long should the PS SBT be? 98 pts MV >48h PSV decreased Enrolled: all readiness criteria satisfied N = 46 PSV 7, 30 min N = 52 PSV 7, 120 min N = 43 Passed, 93% Reintubation 4 (9%) 2 (4%) N = 46 Passed, 88% Perrin et al, Intensive Care Med 2002

21 OBJECTIVE INDEXES Brochard Esteban Ely Valleverdù Esteban RR > 35/min > 35/min > 35/min > 35/min > 35/min PCO 2 Increase > 8 mmhg Increase > 8 mmhg Increase > 8 mmhg Increase > 8 mmhg Increase > 8 mmhg HR > 140 or change 20% > 140 or change 20% > 140 or change 20% > 140 or 20% > 140 or change 20% SaO 2 < 90% < 90% < 90% < 90% SAP mmhg > 180 < 90 > 180 < 90 > 180 < 90 > 160 < 80 > 200 < 80

22 SUBJECTIVE INDEXES Brochard Esteban Ely Valleverdù Esteban Diaphoresis Agitation Anxiety Depressed Mental Status

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24 What mode? T piece PSV How long? Esteban et al, AJRCCM T Piece (A) PSV (B) A) Esteban et al, AJRCCM 1999 B) Perrin et al, Intensive Care Med 2002

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31 Summary of SBTs SBT is an integral part of a weaning trial Method for SBT does not significantly influence the rates of trial failure reintubation successful extubation Duration of SBT using T-piece or PS longer than 30 minutes is unnecessary in simple weaning 120 minute SBT might be preferable in difficult weaning

32 2-Step approach: Daily screening of respiratory function (index) Spontaneous Breathing Trials % of pts on MV Days control (151 pts) intervention (149 pts) Ely et al N Engl J Med 1996 Self extubation, reintubation, tracheostomy, ICU costs

33 The Difficult- to-wean Patients

34 Esteban et al., N Engl J Med 1995, 332: ICUs: -12 mo prospective study -546 pts meeting weaning criteria

35 Brochard et al., AJRCCM 1994, 150: ICUs: Creteil, Rome, Barcelona -18 mo prospective study -456 pts meeting weaning criteria

36 Comparison of the two studies Two different protocols for using PSV Different criteria for intolerance between the T- piece arm and the low PS setting

37 T-tube vs PS COPD Screened 77 patients Excluded 2 Eligible T-tube trial 75 Trial Success 23 (31%) Trial Failure 52 (69%) T-tube 26 PS 26 Successful Weaning 20 (77%) Successful Weaning 19 (73%) Failed Weaning 6 (23%) Failed Weaning 7 (27%) Vitacca et al. Am J Respir Crit Care 2001; 164: 225

38 PSV T-piece AJRCCM 2001;164:

39 Summary In the ICU, T-tube and PS are equally effective as methods of weaning the difficult-to-wean patients. In the two studies with SIMV arm, SIMV is the worst method of weaning.

40 Do we need a protocol?

41 Daily screening of respiratory function and trials of SBT: Is this study evidence that protocols are necessary? % of pts on MV Days control (151 pts) intervention (149 pts) Ely et al, N Engl J Med % control patients: SIMV

42 Protocol did not reduce MV in a closed ICU with high level of physician availability.

43 Do we need a protocol? We need Knowledge Physician availability

44 An automated system for driving pressure support ventilation and managing weaning. A multicenter study

45 The role of NIV

46 NIV to treat extubation failure

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48 Non-Invasive Ventilation (n.114) Conventional Therapy (n.107) Absolute Risk Difference Relative Risk (95% CI) p-value Mortality 25% 14% 11.4% ( ) 1.75 ( ) 0.05 Reintubation 49% 49% 0% 0.99 ( ) ns

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50 Non Invasive Ventilation as weaning technique

51 patients failed initial SBT

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53 High percentage of salvage NIV in O 2 group

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55 Extubation followed by NIV after 2 days of MV Control NIMV Nava et al. Ann Intern Med 1998;128:721

56 % of patients 60 days mortality (%) in patients with acute exacerbation of COPD using NIPPV as a weaning technique * NIPPV Control Nava et al. Ann Intern Med 1998;128:721

57 Non Invasive Ventilation in spontaneous breathing trial failure (x3) Ferrer et al. Am J Respir Crit Care Med 2003;168:70-76

58 Survival of patients receiving NIV to prevent extubation failure in patients with successful SBT subgroup analysis Ferrer et al. Am J Respir Crit Care Med 2006;173:164-70

59 Ferrer et al, Lancet 2009;374:

60 NIV after extubation in patients who develop hypercapnia during a spontaneous breathing trial Ferrer et al, Lancet 2009;374:

61 Time elapsed from extubation to development of respiratory failure NIV immediately after extubation in patients who develop hypercapnia during a spontaneous breathing trial Ferrer et al, Lancet 2009;374:

62 ως Ηλικία > 65 ΧΑΠ Καρδιακή ανεπάρκεια ως αιτία μηχανικού αερισμού ΒΜΙ>30 APACHE II > 12 Δύσκολο/παρατεταμένο weaning Ανεπάρκεια διαχείρησης εκκρίσεων Προβλήματα βατότητος αεραγωγών Παρατεταμένος μηχανικός αερισμός (> 7 ημέρες) > 2 συνυπάρχουσες νοσηρότητες

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65 Ηλικία < 65 Όχι ΧΑΠ Όχι Καρδιακή ανεπάρκεια ως αιτία μηχανικού αερισμού ΒΜΙ<30 APACHE II <12 απλό weaning Επάρκεια διαχείρησης εκκρίσεων Όχι προβλήματα βατότητος αεραγωγών Όχι παρατεταμένος μηχανικός αερισμός (< 7 ημέρες) < 2 συνυπάρχουσες νοσηρότητες

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68 Inspiratory Muscle Training when weaning fails Rarity of randomized controlled trials Case series Few patients, usually no control group Various IMT regimes Conflicting results

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70 Patients weaned *

71 IMT for respiratory muscle weakness in the ICU Scientific sound but not proven Helpful when used before surgery and MV During MV and when weaning fails More RCT are needed Large number of patients (IMT & control) Standardized IMT protocols Specific patient groups

72 Mechanical Ventilation Assessment of Weaning Readiness: Indices Spontaneous Breathing Trial = SBT T-piece or PS, 30 or 120 min A method for Weaning Difficult-to-wean patients (i.e., patients who fail SBT) T-piece or PS