Awareness. Depth of anesthesia monitoring, patient experiences, human factors, sedation, consent and medicolegal issues

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1 Awareness Depth of anesthesia monitoring, patient experiences, human factors, sedation, consent and medicolegal issues Lynn Puissant An Rutten Dr. De Sloovere 30/01/2015

2 AWARENESS Depth of anesthesia (DOA) monitoring Patient experiences Sedation Human factors Medicolegal issues

4 DOA-monitoring Processed EEG (peeg) - Bispectral index (BIS) - E-Entropy - Narcotrend Compact Niet-EEG gebaseerd - Isolated Forearm technique (IFT)

5 BIS Sensor op het voorhoofd Meet en verwerkt elektrische activiteit hersenen (EEG) Getal, zonder eenheid (streefwaarde = 40-60)

6 BIS Ontwikkeld op basis EEG gezonde personen Combi power spectrum (f) en bispectrum (relatie tussen golven met verschillende f)

7 E-entropy Sensor op het voorhoofd State entropy (SE): EEG Response entropy (RE): EEG + FEMG - facial muscle activation meet antwoord Twee getallen, zonder eenheid (streefwaarde = 40-60) - regelmatige golflengtes en amplitudo s = lage entropy-waarde - onregelmatige golflengtes en amplitudo s = hoge entropy-waarde

8 Narcotrend Compact Sensor op het voorhoofd Interpreteert vorm EEG: golflengte en amplitude Classificatie A-F (streefwaarde = E)

9 IFT (1977) BD manchette > syst BD NMBA toedienen (contralateraal infuus) Spontane bewegingen van de arm met manchette of op vraag = wakefulness Cuff lossen na 20min Zo opnieuw NMBA nodig inflatie cuff

10 NAP5 * DOA: beperkt gebruik in UK. - 2,8% van AA peeg - Isolated Forearm technique 0,03% * Ierland: DOA in 9% AA Sury MRJ, Palmer JHMG, Cook TM, Pandit JJ. The state of UK anaesthesia: a survey of National Health Service activity in Br J Anaesthesia 2014; 113: Jonker WR, Hanumanthiah D, Ryan T, Cook TM, Pandit JJ, O Sulivan EP. Who operates when, where and on whom? A survey of anaesthetic-surgical activity in the Republic of Ireland as denominator of NAP5. Anaesthesia 2014, doi /anae Jonker WR, Hanumanthiah D, Ryan T, Cook TM, Pandit JJ, O Sulivan EP. A national survey (NAP5-Ireland baseline)to estimate an annual incidence of accidental awareness during general anaesthesia in Ireland. Anaesthesia 2014; doi: /anae.12776

11 141 AAGA 6 (4,3%) ondanks DOA What are we missing?

12 DOA: 1% volatiele A curare 3,5% volatiele A + curare 23,4% TIVA + curare Pandit JJ et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesthesia (4):

13 Potentieel voordeel DOA monitoring tijdens TIVA + NMBA - Dosis? - Hypotensie - Toevoer anestheticum - Curare

14 Pitfalls bij het gebruik van peeg Ten eerste: Diepte anesthesie golven. : - Eerst toename laagfrequente golven, daarna toename hoogfrequente - Hogere amplitudo s - Regelmatiger EEG - Burst suppressie Ketamine, N2O en Xenon: - NIET dit typisch effect op EEG - Toediening ketamine kan zelfs BIS verhogen DOA minder betrouwbaar bij gebruik van deze anesthetica. Lobo FA, Schraag S. Limitations of anaesthesia depth monitoring. Current Opinion in Anesthesiology 2011;24:657 64

15 Pitfalls bij het gebruik van peeg Ten tweede: Verschillende anesthetica die het EEG patroon typisch veranderen, doen dit NIET identiek anestheticum A : BIS 40 anestheticum B : BIS 40

16 Pitfalls bij het gebruik van peeg 1) Ibrahim et al. Pt LA/LRA + sedatie met propofol, sevofluraan of midazolam Respons Observers s Assessment of Alertness/Sedation (OAAS) BIS was een significant betere predictor voor sedatie bij propofol dan bij sevofluraan of midazolam. 2) Schwab et al. 1 MAC/1.5 MAC sevofluraan vs. 1 MAC/1.5 MAC halothaan BIS waardes halothaan significant > sevo 1, Ibrahim AE, Taraday JK, Kharasch ED. Bispectral index monitoringduring sedation with sevoflurane, midazolam, and propofol.anesthesiology 2001;95: ,Schwab HS, Seeberger MD, Eger EI II, Kindler CH, Filipovic M.Sevoflurane decreases bispectral index values more than does halothane at equal MAC multiples. Anesthesia & Analgesia2004;96:

17 BIS vs. ETAG B-Aware-trial RCT multi-center 2364 pt: routine care (HF, BD) BIS monitoring (40-60) Routine care: 11 AAGA BIS: 2 AAGA p= = significant BIS > standard care Myles PS, Leslie K, McNeil J, Forbes A, Chan MT. Bispectral index monitoring to prevent awareness during anaesthesia: the B-Aware randomised controlled trial. Lancet. 2004;363:

18 BIS vs. ETAG B-Unaware-trial: RCT single center ETAG protocol 1941 pt BIS (40-60) ETAG ( MAC) BIS 2 AAGA ETAG 2 AAGA Risico reductie = 0% Geen superioriteit van BIS Avidan MS, Zhang L, Burnside BA, et al. Anesthesia awareness and the bispectral index. New England Journal of Medicine. 2008;358:

19 BIS vs. ETAG BAG-RECALL-trial: RCT 3 centra ETAG protocol 5809 pt 5713 assessed BIS (40-60) ETAG ( MAC) BIS 7 absolute 19 absolute + mogelijk AAGA ETAG 2 absolute 8 absoluut + mogelijk AAGA p= 0.98 p= 0.99 (niet-significant) Geen superioriteit van BIS Avidan MS, Jacobsohn E, Glick D, et al. Prevention of intraoperative awareness in a high-risk surgical population. New England Journal of Medicine. 2011;365:

20 Guidelines Cochrane review NICE NAP5

21 Cochrane review (2007) 31 trials BIS kan AAGA verminderen bij high risk patiënten t.o.v. standard care, maar niet t.o.v protocol voor ETAG monitoring. BIS kan nood propofol verlagen met 1.44mg/kg/u en MAC met 0.14 BIS verlaagt de recovery tijd (ogen openen, extubatie, tijd op PAZA) BIS verlaagt de hospitalisatieduur niet

22 NICE guidelines (2012) 1) BIS is optie bij high risk patiënten 2) BIS is aan te raden bij alle patiënten bij TIVA 3) Idem voor E-entropy en Narcotrend 4) Anesthesisten moeten voldoende training en ervaring krijgen met DOA monitors alsook hun beperkingen Meer research nodig NICE publicatie tijdens NAP5-studie Geen effect op registraties in NAP5

23 Aanbevelingen NAP5 1) Anesthesisten moeten bekend zijn met de principes en interpretatie van DOA. Integratie in opleiding. 2) Protocols/algoritmes moeten gemaakt worden voor het gebruik van DOA en dosering anesthetica. 3) Anesthesisten moeten weten dat NMBA het risico op AAGA verhoogd en dus het gebruik van DOA het risico op AAGA logisch kan verlagen in deze gevallen 4) Als we DOA gebruiken beginnen voor/tijdens inductie en voortzetten tot NMBA voldoende uitgewerkt is.

25 PATIENT EXPERIENCES Anaesthesia and memory Memory types Explicit or declarative memory Trauma memory Implicit memory False memory Source memory

26 PATIENT EXPERIENCES Relationship memory and AAGA Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

27 PATIENT EXPERIENCES Post-traumatic stress disorder Incidence of PTSD: up to 70% in patients who have experienced awareness with subsequent explicit recall Given the potentially catastrophic psychological sequelae of awareness and the difficulty treating, there is a strong motivation to prevent from ever occurring.

28 PATIENT EXPERIENCES PSYCHological Sequelae Of Surgery Whitlock EL, Rodebaugh TL, Hassett AL, Shanks AM et al. Psychological Sequelae of Surgery in a Prospective Cohort of Patients from Three Intraoperative Awareness Prevention Trials. Anesth Analg. 2015; 120:

29 PATIENT EXPERIENCES Psychological sequelae of surgery Definite or possible AWR Perceived threat of life at the time of surgery Whitlock EL, Rodebaugh TL, Hassett AL, Shanks AM et al. Psychological Sequelae of Surgery in a Prospective Cohort of Patients from Three Intraoperative Awareness Prevention Trials. Anesth Analg. 2015; 120:

30 PATIENT EXPERIENCES Distribution by phase of anesthesia / symptoms Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

31 PATIENT EXPERIENCES Michigan score - Distress Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

32 PATIENT EXPERIENCES Michigan score NPSA score Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

33 PATIENT EXPERIENCES Duration of AAGA Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

34 PATIENT EXPERIENCES Duration of AAGA Michigan / NPSA Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

35 PATIENT EXPERIENCES Time delay for reporting Michigan / NPSA Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

36 PATIENT EXPERIENCES Awareness support pathway Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

38 SEDATION Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

39 SEDATION Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

41 HUMAN FACTORS Induction Drug errors from mislabelling, failure to mix drugs, omission of drugs or syringe swaps Mind the gap errors delayed or omitted maintenance drugs Inadequate dosage of induction agents due to errors of knowledge or judgement Ampoule label design Errors of judgement or knowledge Difficult airway management and obesity Distraction by colleagues talking, teaching, interruptions Distraction by unexpected difficulty failed airways, failed vascular access, other unexpected patient complications, equipment failure Busy lists with multiple changes, staff shortages Tiredness Rushing Lack of clarity of roles in the anaesthetic room The need for rapid sequence induction Lack of availability of extra drugs due to local policy Junior trainees working unsupervised

42 HUMAN FACTORS Maintenance Under-dosing to maintain cardiovascular stability Under-dosing to lessen risk to a fetus Under-dosing due to inattention or judgement errors Termination of anaesthesia too soon before surgery had finished Poor vigilance of the IV cannula so disconnection, leaks, infusions into subcutaneous tissues or displacement of the cannula was not noticed Not using a non-return valve on IV fluid port when multi-lumen IV connectors are used Non-availability of appropriate IV pumps Vaporisers: prolonged gap in administration of anaesthetic on transfer (failing to turn on the vaporiser, starting volatile agents at too low level, at too low fresh gas flow or using an unchecked (and faulty) vaporiser) Failure to measure exhaled or end tidal anesthetic concentration (ETAC) Failure to use depth of anesthesia monitoring Type of anesthesie surgery (ECMO/CPB/shunt)

43 HUMAN FACTORS Emergence Turning anaesthetic agents off because of poor communication Turning anaesthetic agents off because of poor understanding of offset times of newer volatile agents Rushing Mis-timing, overdosing or unnecessary use of muscle relaxants Failure to monitor degree of residual neuromuscular blockade or the effects of reversal agents Transfer of a sedated patient to ICU / PACU

44 HUMAN FACTORS Management of AAGA Incomplete communication to patients pre-operatively about the risks of AAGA, especially when the risk was increased (e.g. difficult airway management anticipated, awake extubation planned, relative underdosing planned due to patient instability) Not communicating with patient while AAGA was suspected to be occurring Not deepening anaesthesia when there were signs of inadequate anaesthesia Not adding or deepening anaesthesia when awake paralysis was detected at induction or emergence Not acknowledging, empathising and believing when patients reported AAGA (including anaesthetists, nurses, surgeons) Poor documentation of anaesthetic conduct (including occasional factual inaccuracy)

45 HUMAN FACTORS Prevention Checklists Cook TM, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. Br J Anaesth 2014; 113:

46 HUMAN FACTORS Prevention Checklists Consent for both general anaesthesia and sedation Technology Humanity Use of volatile monitoring, depth of anaesthesia monitors When using equipment, it is essential knowing its uses and limitations

48 MEDICOLEGAL ISSUES The overall proportion of medicolegal claims after AAGA in the NAP5 cohort appears to be low, although, as litigation is often delayed, further claims may emerge as time passes. The NAP5 also indicated that only about 1/5 of cases resorted to complaint and only 4% to legal action. Claims for awareness: 2% of all ASA closed claim database (2010)

49 MEDICOLEGAL ISSUES Causes of awareness in ASA Closed Claims Kent CD: Awareness during general anesthesia: ASA Closed Claims Database and Anesthesia Awareness Registry. ASA Newsletter 74(2): 1416, 2010.

50 TAKE HOME MESSAGES Despite short duration of awareness, half of the patients suffer significant distress. The patients interpretation of what is happening at the time of the awareness seemed central to later impact. Communication and consent are extremely important for patients undergoing sedation. HF should be considered in investigation / prevention of AAGA.