Risk Reduction in Sedation
and Analgesia
Rowland P. Wu, MD
Adapted from Glynne D. Stanley, MD
Overview
Complications occur because of:

Inappropriate patient selection

Unanticipated responses from patient or
equipment

Over-medication

Wrong patient/wrong site/wrong procedure
Strategies to reduce risk,
‘patient selection’

Improve patient selection

ASA Classification

airway assessment and history

identify other factors e.g. pregnancy, obesity
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)
ASA Classification

ASA 1
ASA 2
ASA 3
Normal, healthy patient

Stable mild systemic disease

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)
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.
Mallampati classification
Airway Assessment
Mallampati classification
Neck extension
Thyromental distance
(?short neck)
Interincisor distance
(?poor mouth opening)
Concurrent obesity
(History of airway
problems)
Letters
and bracelets
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
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
Ideal Patient Positioning
Obstructed Airway
Oral Airway
Nasal Airway
Mask Ventilation
EtCO2 Apparatus
EtCO2 Tracing
Unanticipated events

Cardiac instability/dysrhythmia

Respiratory depression and/or airway
obstruction

Neurological ‘disconnection’

Equipment malfunction
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
Unanticipated respiratory
events

Respiratory
complications

Possible causes

overmedication
 depression

relative
 airway

absolute
obstruction
 bronchospasm

patient position

‘foreign material’

allergic reaction
Unanticipated neurological
events

Neurological
‘Disconnection’
 drowsiness
 unresponsiveness

Possible causes




overmedication
Hypoxemia
hypercarbia
cerebral ischemia
 uncooperative

 combative

 disinhibition

hypoxemia
cerebral
hypoperfusion
undermedication?
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

Equipment problems:
E.C.G.

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:
Non-invasive BP

Problems
 no
reading

Possible causes:
 HYPOTENSION!
 HYPERTENSION!
cycling  cuff leak
 wrong size cuff
 very low/high BP
 arrhythmia e.g. AF
 ??Arterial line
 tubing kinked
 patient/MD movement
 repetitive
Equipment problems:
Pulse oximetry


Problems:
 no
Possible causes

reading


 low
reading
 intermittent
 frequent

trace
alarm



no pulse!
hypoxemia!
decreased perfusion
dye injection
electrical interference
inappropriate sat/pulse
settings
incident light/nail polish
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.
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
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 0.51mg increments
 Duration 1-2 hours
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
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
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
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 23hrs
 Interaction with MAOIs
Overmedication

Why does overmedication occur?
 Excessive
dose
 Overly sensitive patient,
 concurrent
 Inadequate
medications or disease states
time for effect before more
drug administered
 Abnormal response such as hyperactivity
leading to more medication
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
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
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.
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
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
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.