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

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

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

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. Equipment problems: E.C.G.
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

24. Equipment problems: Non-invasive BP
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

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

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 mcg iv
titrated in 25mcg doses
low dose drug is short acting
Duration of effect 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 mg iv
Onset 2-8 mins, peak 20 mins
Mild vagolytic and antispasmodic
Normeperidine is pro-convulsant
Dose titration mg; 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.