Risk Reduction in Sedation and Analgesia

1. Risk Reduction in Sedation and Analgesia Rowland P. Wu, MD Adapted from Glynne D. Stanley, MD

2. Overview Complications occur because of: • Inappropriate patient selection • Unanticipated responses from patient or equipment • Over-medication • Wrong patient/wrong site/wrong procedure

3. Strategies to reduce risk,‘patient selection’ • Improve patient selection • ASA Classification • airway assessment and history • identify other factors e.g. pregnancy, obesity

4. Patient Selection • Important ‘baseline’ assessments are: • actual or estimated weight • vital signs including baseline oxygen saturation • cardiopulmonary status • general neurological status • previous adverse responses to medication (not just allergy detection)_ • ASA classification • (Baseline airway evaluation)

5. ASA Classification • ASA 1 Normal, healthy patient • ASA 2 Stable mild systemic disease • ASA 3 Severe systemic disease with functional impairment • ASA 4 Severe disease, constant threat to life, not necessarily to be improved by surgery • ASA 5 Moribund patient, not expected to survive without surgery • ASA 6 Brain-dead donor • Emergency (E)

6. Patient Selection • All patients should be carefully evaluated by the MD. Some ASA Class III, and most ASA Classes IV and V will not be suitable for sedation administered by non-anesthesiologists.

7. Mallampati classification

8. Airway Assessment • Mallampati classification • Neck extension • Thyromental distance (?short neck) • Interincisor distance (?poor mouth opening) • Concurrent obesity • (History of airway problems) • Letters and bracelets

9. Patient Selection • Anesthesia consultation should also be considered under the following circumstances: • patient has limited neck motion or cervical instability • patient has abnormal craniofacial anatomy • patient is morbidly obese • patient has a history of sleep apnea • pregnant patients • patient has not been NPO

10. Strategies to reduce risk,‘unanticipated events’ • Have available and be familiar with essential pieces of equipment • basic interpretation of ECG • understand pulse oximetry and know the limitations of use • capnography • reliable oxygen source, equipment for positive pressure ventilation • know how to quickly and reliably get help

11. Ideal Patient Positioning

12. Obstructed Airway

13. Oral Airway

14. Nasal Airway

15. Mask Ventilation

16. EtCO2 Apparatus

17. EtCO2 Tracing

18. Unanticipated events • Cardiac instability/dysrhythmia • Respiratory depression and/or airway obstruction • Neurological ‘disconnection’ • Equipment malfunction

19. Cardiovascular instability Hypotension Tachycardia PVC’s atrial arrhythmias ventricular arrhythmias cardiac arrest! Possible causes hypovolemia allergic reaction overmedication hypoxemia ischemia hypercarbia bleeding Unanticipated cardiovascular events

20. Respiratory complications depression airway obstruction bronchospasm Possible causes overmedication relative absolute patient position ‘foreign material’ allergic reaction Unanticipated respiratory events

21. Neurological ‘Disconnection’ drowsiness unresponsiveness uncooperative combative disinhibition Possible causes overmedication Hypoxemia hypercarbia cerebral ischemia hypoxemia cerebral hypoperfusion undermedication? Unanticipated neurological events

22. Unexpected events:The catastrophe! • Call for help/Code Blue • Discontinue sedative therapy, infusions /transfusions etc • Begin BCLS/ACLS if appropriate • prepare emergency equipment, drugs • try to anticipate resuscitation needs

23. Problems No trace/loss of trace Poor quality Intermittent trace Interference Possible causes ASYSTOLE!! loose leads incorrect placement dry electrodes! greasy skin respiratory variation electrical interference Equipment problems:E.C.G.

24. Problems no reading repetitive cycling very low/high BP ??Arterial line Possible causes: HYPOTENSION! HYPERTENSION! cuff leak wrong size cuff arrhythmia e.g. AF tubing kinked patient/MD movement Equipment problems:Non-invasive BP

25. Problems: no reading low reading intermittent trace frequent alarm Possible causes no pulse! hypoxemia! decreased perfusion dye injection electrical interference inappropriate sat/pulse settings incident light/nail polish Equipment problems:Pulse oximetry

26. Equipment problems:Pulse oximetry • REMEMBER! • Oximetry does not measure respiration • there may be a lag phase, depending on probe site • as with all the equipment: • if it isn’t working at the beginning it will not suddenly get better, it is likely to let you down when you need it most.

27. Strategies to reduce risk,‘over-sedation’ • Have an understanding of the pharmacology involved in conscious sedation • Titrate drugs carefully to patient weight but especially to effect. • Have appropriate reversal agents readily available and know how to use them • Know where other emergency drugs can be found

28. Commonly Used Medications • Midazolam • intravenous/oral/intramuscular/intranasal • Initial dose 0.5-2mg iv over 2 min • Onset 1minute, peak 3-5 mins • Wait full 2 mins between doses with 0.5-1mg increments • Duration 1-2 hours

29. Commonly Used Medications • Valium • Initial dose 2-5 mg iv • Onset 1-5 mins • Wait full 5 mins between doses with 1 mg increments • Duration 3-4 hours

30. Commonly Used Medications • Fentanyl • Onset 1-3 min; peak-effect at 3-5 minutes • Initial dose 25-50 mcg iv • titrated in 25mcg doses • low dose drug is short acting • Duration of effect 30-60 mins

31. Commonly Used Medications • Morphine • Onset 1-6 min • Initial dose 2-5 mg iv • titrated in 2 mg doses but wait 3-5 mins between doses • Duration of effect 3-5 hours

32. Commonly Used Medications • Meperidine • Initial dose 25-50 mg iv • Onset 2-8 mins, peak 20 mins • Mild vagolytic and antispasmodic • Normeperidine is pro-convulsant • Dose titration 12.5-25mg; Duration 2-3hrs • Interaction with MAOIs

33. Overmedication • Why does overmedication occur? • Excessive dose • Overly sensitive patient, • concurrent medications or disease states • Inadequate time for effect before more drug administered • Abnormal response such as hyperactivity leading to more medication

34. Overmedication • What problems does overmedication cause? • Airway obstruction • Hypoxemia and hypercarbia • Loss of protective reflexes • Loss of contact with the caregiver • Hemodynamic instability • Interferes with the procedure

35. Overmedication • How may overmedication be managed? • stop medicating! • open airway and stimulate to breathe • ensure adequate oxygen supply • call for help early, especially if hemodynamic instability • consider reversal of medication • have suction immediately available

36. Overmedication • How may medication be reversed? • Opiates and benzodiazepines are the only drugs with specific antagonists: • REMEMBER: once reversal agents are used this MUST lead to a longer period of post-procedure monitoring.

37. Reversal Agents • NALOXONE, 40mcg - 400mcg slow I.V. • Onset 1-3 minutes, duration 45 minutes • will reverse analgesia • may cause pulmonary edema • beware withdrawal effects if long term narcotic use • may need repeating or infusion

38. Reversal Agents • FLUMAZENIL, • 0.1mg - 0.2 mg I.V. for partial reversal • 0.4mg - 1.0mg I.V. for complete reversal • Onset 1-2 minutes, duration 45 minutes • may precipitate withdrawal seizure • not to be used routinely • half life of benzodiazepine may be long so flumazenil may need to be repeated

42. Summary • Choose your patients carefully. • Check and understand your equipment • Use medication judiciously, you can’t take it out but you can always give more! • Have reversal agents available but remember basic airway techniques. • Be vigilant and prepare for the unexpected.