1. Screening to identify SBT candidates

Transcription

1 Karen E. A. Burns MD, FRCPC, MSc (Epid) Associate Professor, Clinician Scientist St. Michael s Hospital, Toronto, Canada burnsk@smh.ca Review evidence supporting: 1. Screening to identify SBT candidates 2. How to Conduct SBTs Which technique? 3. SBT Duration 1

2 Approximately 40% of the total time spent on mechanical ventilation (MV) is dedicated to weaning [1]. Strategies to limit the duration of invasive MV and ventilator-related complications have been identified as a key research priority by a committee comprised of the ACCP, AARC, ACCM [2]. 1. Esteban A, Chest 1994;106: MacIntyre NR, Chest 2001;6 Suppl: In a qualitative study (n=443 research questions), generated using a multimodal approach and ranked by ICU relatives and physicians, weaning was identified to be among the 21 (top 5%) most important questions [3]. In a UK James Lind Alliance Research Priority Setting Partnership, strategies to prevent damage to the lungs of patients receiving MV was ranked as the #1 research priority for patients, families, and clinicians [4]. 3. Peigne V, Chaize M, Falissard B, et al. Crit Care Med 2011;39: Reay H, et al. Results of a James Lind Alliance Priority Setting Partnership. JICS 2014; 15:

3 The Task Force on Weaning (2008) from 4 international societies [the ERS, ATS, ESICM, SCCM] recommended that: 1. Weaning should be considered as early as possible 2. An SBT was the major diagnostic test to determine if patients can be successfully extubated 3. Initial SBTs should be conducted with either a T-piece or low levels of PS (5 8 cm H 2 O in adults) ± 5 cm H 2 O PEEP [5]. 5. Boles JM, et al. Eur Respir J 2007; 29:

4 Early positive RCTs of protocol-directed screening Ely 1996 Kollef 1997 Marelich 2000 Selected Patients Namen 2001 (neurosurgical patients) Randolph 2002 (pediatric patients) Highly Structured Settings Krishnan 2004 (Johns Hopkins) Blackwood et al, summarized 17 trials (n = 2,434) in a systematic review and meta-analysis. Most trials compared once daily screening to usual care. **Usual care required a physician order to conduct SBTs. Blackwood B, Cochrane D, 2014; Issue 11: CD

5 26% reduction in total duration of MV [n = 14 trials, 95% CI (13% - 37%), p = ] 70% reduction in weaning time [n = 8 trials, 95% (CI 27% - 88%), p = 0.009] 11% reduction in ICU stay [n = 9 trials, 95% CI (3% - 19%), p = Only 1 trial (n=385) compared twice daily screening to usual care and found a significantly shorter duration of MV and a trend toward a lower VAP in twice daily screening. No trial compared a strategy of more frequent screening to once daily screening. Marelich, CHEST, 2000;118:

6 Design: 2 parallel, multicenter, pilot RCTs Populations: RELEASE Trial included non-elderly (< 65 years) SENIOR Trial included elderly (> 65 years) adults MV for at least 24 hours Intervention: compared at least twice daily (ALTD) screening to once daily (OD) to identify SBT candidates. Outcomes: Feasibility metrics including Recruitment of 1 to 2 patients/month per ICU > 80% protocol adherence < 10% crossovers from OD to ALTD screening Effect on clinical outcomes Variable RELEASE + SENIOR Trials Combined Once Daily N=77 At Least Twice Daily N=78 p-value Successful extubation 60 (78%) 65 (83%) p=0.5 Time to successful extubation, days 3.5 (5.7 ± 6.2) 2.8 (5.5 ± 6.9) p=0.3 NIV use 6 (8%) 14 (18%) p=0.09 Reintubation 10 (13%) 8 (10%) p=0.6 Tracheostomy 9 (12%) 9 (12%) p=1.0 ICU stay, days (survivors) ICU stay, days (non survivors) Hospital stay, days (survivors) Hospital stay, days (non survivors) 7.5 (9.2 ± 7.4) 9.0 (12.6 ± 12.4) 21 (22 ±13) 11.5 (13.9 ±12) 7.0 (9.9 ±9.9) 8.0 (8.5±7.4) 18 (21 ± 14) 9.2 (12.7 ± 11.4) p=0.4 p=0.08 ICU mortality 21 (27%) 15 (19%) p=0.2 ICU Readmission 6 (8%) 3 (4%) p=0.3 Burns KE, Unpublished 6

7 1. Evidence supports daily screening (vs. usual care) reduces time on MV, weaning time, and ICU stay 2. Additional evidence needed to assess net benefits of more frequent screening 3. Future trials should compare more frequent screening to once daily screening 7

8 Clinicians conduct SBTs to facilitate decision-making regarding timely extubation In making extubation decisions, clinicians trade-off the risks associated with a premature failed attempt at extubation (too early) and the complications associated with prolonged ventilation (too late). Several techniques are commonly used to conduct SBTs, - Pressure Support ± PEEP - CPAP - Automatic Tube Compensation - T-piece (PS 0 cm H 2 O, PEEP 0 cm H 2 0) A Cochrane review (n=9 trials) compared PS and T-piece weaning in critically ill adults. Nonsignificant differences between PS and T-piece weaning weaning success pneumonia reintubation ICU mortality and LOS In a subgroup analysis, patients were significantly more likely to pass a PS (vs. a T-piece) SBT [RR 1.09, 95% CI 1.02 to 1.17] in 4 trials (n= 940 patients). Limitations: Focused on weaning, limited to full RCT publications, limited to adults, and compared 2 weaning techniques (PS vs. T-piece) ONLY. Ladiera et al, Cochrane Database 2014 May 27;(5):CD

9 Published a SR/MA (n=12 trials, n=2161) compared PS and T-piece weaning in critically ill adults (including tracheostomized patients). PS vs. T-piece weaning did not influence: weaning success reintubation ICU mortality Subgroup analysis suggested that PS may be superior to T-piece with regard to weaning success for simple weaning patients [RR 1.44 ( )] but not for difficult [RR 1.45 ( )] or prolonged [RR 0.85 ( )] weaning patients. Pelligrini et al, Respir Care. 2016;61(12): WoB PS vs. T-piece 0.70 ( ) 10 [n=142] I 2 =78% PS vs. CPAP 0.91 (0.70, 1.18) [n=154] CPAP vs. T-piece 0.87 (0.74, 1.02) [n=136] PTP 0.70 ( ) 9 [n=129] I 2 =73% 0.96 (0.79, 1.18) [n=156] 0.82 (0.68, 1.00 [n=78] I 2 =74% Sklar et al, AJRCCM. 2017;159(11):

10 Pre vs. Post Extubation WoB PS vs. Extubation 0.54 ( ) [n=63] I 2 =82% T-piece vs. Extubation 0.86 (0.72, 1.02) [n=77] NS I 2 =67% p=0.08 0/0 vs. Extubation 0.99 (0.84,1.17) [n=43] NS I 2 =29% p=0.91 PTP 0.51 ( ) [n=52] I 2 =0% 0.77 (0.64, 0.94) [n=52] I 2 =62% P= (0.83, 1.08) [n=32] NS I 2 =19% p=0.44 Sklar et al, AJRCCM. 2017;159(11): PS SBTs reduce respiratory effort compared with T-piece SBTs. o o True, for WoB; I 2 =68% (n=149) and for PTP; I 2 =62% (n=142)? Impact on clinical outcomes..? Good/Bad? 2. 0/0 and T-piece SBTs more accurately reflect the physiologic conditions after extubation T-piece vs. Extubation had no effect on WoB and significantly reduced PTP with I 2 =68% (n=52) 0/0 vs. Extubation had no effect on WoB (n=77) or PTP (n=52)?no effect =?equivalency 10

11 Scoping review evaluating the body of evidence directly comparing alternative SBT techniques on clinically important outcomes. Strengths: Comprehensive search, No language restrictions, Abstracts from 5 conferences spanning 25 years. Burns KE, Crit Care 2017 Jun 1;21(1):127. Inclusion Criteria: Study Design: Randomized or quasi-randomized trials Patients: Critically ill adults or children Interventions: Directly comparing 2 or more SBT techniques Outcomes: Reporting at least one clinically important outcome: Primary Outcomes: initial SBT success, extubation success, reintubation Secondary Outcomes: time to extubation or successful extubation, time to first successful SBT, mortality, VAP, total duration of MV, ICU or hospital LOS, post extubation NIV, or adverse events. 11

12 Exclusion Criteria: (i) neonatal or patients with a tracheostomy (ii) Evaluated SBTs as part of a weaning strategy (iii) Included automated SBTs (e.g., SmartCare, Intellivent ) incorporated in weaning strategies (iv) Compared NIV vs. continued invasive MV. (v) Compared conduct of an SBT vs. no SBT. 3,785 unique citations 3,602 citations excluded 183 potentially relevant citations 152 citations excluded 65 crossover studies 31 not randomized 27 weaning studies 13 SBT vs. no SBT 8 physiologic 8 other 31 included trials (n=3,541) *11 (T-piece vs. PS) 9 (T-piece vs. CPAP) 12

13 9 trials n=1,901 I 2 = 77% p=0.96 RR 1.00 [0.89, 1.11] Post hoc 8 trials n=1,381 I 2 = 0% p=0.03 RR 1.06 [1.01,1.12] 11 trials n=1,904 I 2 = 0% p=0.007 RR 1.06 [1.02, 1.10] Post hoc 10 trials n=1,384 I 2 = 0% p=0.03 RR 1.06 [1.01, 1.12] Burns KE, Crit Care 2017 Jun 1;21(1):

14 Burns KE, Crit Care 2017 Jun 1;21(1):127. No of trials [n] Quality assessment No of patients Effect Risk of bias Inconsistency Indirectness Imprecision Pressure Support T-piece Relative Risk Quality (95% CI) Difference Operative trials (<24 hours) 2 trials no serious serious 1 [548] risk of bias not serious serious 2 173/274 (63.1%) 226/274 (82.5%) RR 0.86 (0.61 to 1.22) 115 fewer per 1000 (-322, + 181) ÅÅOO LOW Nonoperative trials 7 trialsno [1353] serious risk of bias not serious not serious not serious 536/680 (78.8%) 499/673 (74.1%) RR 1.07 (1.01 to 1.13) 52 more per 1000 (+7, +96) ÅÅÅÅ HIGH p=0.3 14

15 Comparison Trials [n] Risk Ratio (95% CI) p-value I 2 ATC/CPAP vs. CPAP ATC/CPAP vs. PS 3 trials [247] 3 trials [276] 1.12 (1.04, 1.22) % 1.10 (1.01, 1.20) % -No SBT techniques demonstrated an effect on reintubation rate -No effect on secondary outcomes Burns KE, Crit Care 2017 Jun 1;21(1):127. Feature Ladiera et al Pellegrini et al Burns et al Population Adults Adults Adults/Pediatrics Interventions Weaning (9 trials) Subgroup: SBT (4 trials) Weaning (12 trials) Alternative SBT techniques (11 trials) Trials Included 9/exc 4 Included 5/exc 4 Reference category SBT success NA NA No effect Weaning or Extubation success No effect No effect 6% more likely to be SE with PS (vs. T- piece) (11 trials) Reintubation No effect No effect No effect Subgroup or Post hoc analysis 9% more likely to pass a PS vs. T- piece SBT (n=4 trials) PS simple wean T-piece prolonged wean 6% more likely to pass a PS vs. T-piece SBT (8 trials) 15

16 RCTs?Proportion of Group 1 pts? Bedeneau, AJRCCM, 2016; 195: Operative vs. Nonoperative Patients 1. Most patients submitted to MV, especially those with high pre-test probability of success, can be easily separated from MV after an initial SBT (WIND) <24 hrs MV 2. The most important question in patients with a high pretest probability of SBT & extubation success may be whether an SBT is necessary. 3. Questions regarding the best SBT technique to use may be particularly relevant to patients with indeterminate or low pre-test probability of SBT/extubation success. 16

17 1. PS SBTs may facilitate extubation decision-making. 2. Even if PS SBTs underestimate post-extubation WOB passing an SBT may: -offset clinician reluctance to extubate some patients -result in more timely and successful extubation Pre-test probability T-piece SBTs may be appropriate in selected patients (e.g. severe LV dysfunction, neuromuscular weakness) especially when low likelihood of extubation success (high uncertainty exists regarding their ability to breathe on their own) when clinicians prioritize a low FP rate for passing an SBT (to avoid the risks associated with extubation failure). Conversely, when T-piece SBTs (vs. PS SBTs) are used in patients with a high likelihood of extubation success they may induce a higher FN rate. 17

18 Only 3 RCTs compared SBTs of different durations All 3 trials compared 30 or20 min vs. 120 min Chawla, 2001 (n=200) Esteban, 1999 (n=526) Perrin, 2002 (n=98) 18

19 30 min vs. 120 minutes SBTs Trials [n] Relative Risk 95% CI p-value SBT success 3 [n=824] Reintubation 2 [n=624] Weaning failure rate 3 [n=824] , , , Burns KE, Unpublished minute SBTs are likely sufficient for most patients 2. Which patients benefit from longer SBTs? 3. Duration in patients who fail an initial SBT? 19

20 Task Force on Weaning 2008 Screening Consider Weaning as Early as Possible ATS/ACCP Guideline 2016 Pts MV> 24 hrs ventilation liberation protocol SBT Technique SBT Duration? SBTs conducted with T-piece or PS ± PEEP 30 minutes (conditional, low quality)? SBTs conducted with PS ± PEEP (not T-piece or CPAP) (conditional, moderate quality) No mention 20

21 Randomized 430 patients to protocolized sedation or protocolized sedation + DI Found nonsignificant differences between arms in Median time to successful extubation, ICU and hospital LOS, Delirium A subsequent meta-analysis confirmed no effect of DI on duration of ventilation or ICU LOS Benefits of DI is an increase in spontaneous breathing ABC Trial (n=336) randomized to SATs + SBTs or SBT protocol alone Patients randomized to the SAT/SBT arm spent more days breathing without assistance at d28, lower mortality at 1 year, and shorter ICU/hospital LOS 21

22 Evidence supports using as little sedation as possible Sedation protocols and titration to scales have led to improved outcomes (ventilation, ICU and hospital LOS, delirium) PAD guidelines recommend titration to a light (rather than deep sedation level) in most patients (unless contraindicated) More trials are needed to assess the merits of DI and SATs/SBTs 1) What is the optimal screening frequency to identify SBT candidates? - Is there benefit to more frequent screening? 2) Amidst daily screening, is one SBT technique superior to another for most patients? - Differ based on weaning difficulty? - Differ in different patient populations? 3) What is the optimal SBT technique and duration in patients who fail an initial SBT? 22

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