PROCEDURAL%20SEDATION%20FOR%20ADULTS

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PROCEDURAL SEDATIONFOR ADULTS

• Dr. CATHERINE GALLANT
• Department of Anesthesiology
• University of Ottawa
• General Campus

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OUTLINE

• Definition
• Indications for use
• Contraindications
• Pharmacology
• Complications

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DEFINITION

• A technique to provide an altered state of
  consciousness by administration of medications
  that permits a patient to undergo painful
  procedures but still respond to verbal commands
  while maintaining an unassisted airway

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INDICATIONS

• Used to facilitate many diagnostic and
  therapeutic procedures
• May be used intra-operatively
• May be performed in a location remote from the
  operating room
• Ever increasing demand fuelled by patients
• Limited capacity for anesthesiologists to provide
  these services

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APPLICATIONS

• Primarily day surgeries
• Lack of dependence on hospital beds
• More flexibility in scheduling
• Shorter waiting lists
• Improved efficiencies
• Low morbidity and mortality
• Low rates of complications
• Lower costs
• Less special investigations required

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APPLICATIONS

• Dental
• Dermatology
• Gynecology
• General surgery
• Ophthalmology
• Orthopedics
• Pain Clinic
• Plastic surgery
• Urology

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DEFINITIONS

• Analgesia - Relief of pain without intentionally
  producing a sedated state. Altered mental status
  may occur as a secondary effect of medications
  administered for analgesia.

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DEFINITIONS

• Minimal sedation drug induced state where the
  patient responds normally to verbal commands.
  Cognitive function and coordination may be
  impaired but ventilatory and cardiovascular
  function are unaffected.
• Anxiolysis alternate term

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DEFINITIONS

• Moderate sedation and analgesia a drug induced
  depression of consciousness where the patient
  responds purposefully to verbal commands alone or
  when accompanied by light touch. Protective
  airway reflexes and adequate ventilation are
  maintained without intervention. Cardiovascular
  function remains stable.
• Conscious sedation

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DEFINITIONS

• Deep sedation and analgesia - A drug induced
  depression of consciousness where the patient
  cannot be easily aroused but responds
  purposefully to noxious stimulation. Assistance
  may be needed to ensure the airway is protected
  and adequate ventilation maintained.
  Cardiovascular function is usually stable.

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DEFINITIONS

• General anesthesia a drug induced loss of
  consciousness, during which the patient cannot be
  aroused, even with painful stimuli, and often
  requires assistance to protect the airway and
  maintain ventilation. Cardiovascular function may
  be impaired.

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EUROPEAN UNION OF MEDICAL SPECIALISTS

• Level 1
• Fully awake
• Level 2
• Drowsy
• Level 3
• Rousable by normal speech

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OBJECTIVES

• To achieve sedation level 2 and 3 (minimal to
  moderate sedation) which allows patients to
  undergo and tolerate unpleasant procedures
• To avoid deeper levels of sedation and the
  related complications
• This cannot be completely avoided!
• Continuum which is difficult to divide into
  discrete stages
• Always maintain verbal contact

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BENEFITS

• Appropriate sedation/analgesia will allow the
  patient to tolerate unpleasant procedures by
  relieving anxiety, discomfort or pain
• In the uncooperative patient, sedation/analgesia
  may facilitate those procedures which are not
  uncomfortable but which require that the patient
  not move

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QUALIFIED INDIVIDUALS

• Competency based education, training and
  experience in
• Patient evaluation
• Performance of sedation
• Knowledge of pharmacology of drugs used
• Rescuing the patient from complications of deeper
  levels of sedation
• Airway compromise
• Inadequate ventilation
• Cardiovascular instability

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PATIENT EVALUATION

• Screening for medical risk factors
• How will these alter response to sedation?
• Abnormalities of major organ systems?
• Previous adverse reactions with
  sedation/analgesia as well as regional and
  general anesthesia?
• Allergies to drugs?
• Medications drug interactions?
• History of drug and alcohol abuse?
• NPO status

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PATIENT EVALUATION

• Abnormalities of major organ systems
• Cardiac
• Respiratory
• Renal
• Hepatic

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PATIENT EVALUATION

• Previous adverse reactions with
  sedation/analgesia as well as regional and
  general anesthesia
• Details
• Where it happened

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PATIENT EVALUATION

• Allergies to drugs?
• What is the reaction?
• When did it occur?
• Family history?

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PATIENT EVALUATION

• History of drug and alcohol abuse?
• May indicate tolerance
• Cross tolerance between classes of drugs

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PATIENT EVALUATION

• Review medications possible drug interactions?
• MAOIs such as phenelzine (Nardil) ,
  tranylcypromine (Nardil), moclobemide

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PATIENT SELECTION

• Focused physical exam
• Evaluation of airway
• Auscultation of heart and lungs
• Assessment vital signs
• Review labs
• Consider consult prn

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PATIENT SELECTION

• Airway issues that may present concerns
• History
• Previous problems with anesthesia or sedation
• Snoring, stridor or sleep apnea
• Advanced rheumatoid arthritis
• Chromosomal abnormalities e.g. trisomy 21
• Physical examination
• Obesity especially involving neck and facial
  structures

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PATIENT SELECTION

• Airway issues that may present concerns
• Physical examination
• Short neck, limited neck extension, decreased TMD
  of lt 3 cm in adult, neck mass, c-spine disease or
  trauma, tracheal deviation, dysmorphic features
• Small mouth opening (lt 3 cm in adult), protruding
  incisors, loose or capped teeth, dental
  appliances, high arched palate, macroglossia,
  tonsillar hypertrophy
• Micrognathia, retrognathia, trismus, significant
  malocclusion

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DIFFICULT AIRWAY
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PATIENT SELECTION

• Who is a candidate for sedation?
• ASA 1 and ASA 2
• ASA 3 in stable condition
• Must be compatible with the procedure
• Must be capable of giving informed consent

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PATIENT SELECTION

• Who is at increased risk of complications?
• Extremes of age
• Multiple co-morbidities
• Severe systemic disease
• Drug and/or alcohol abuse
• Uncooperative patient
• Morbidly obese patient
• Potential difficult airway
• Obstructive sleep apnea

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ADVANCED AGE

• Higher risk of adverse events
• Increased sensitivity to sedative drugs
• Medication interactions
• Higher peak serum levels of medications

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MULTIPLE CO-MORBITIES

• ?ing ASA status correlates with ?ing risk of
  adverse events (ASA III or gt)
• Any co-morbidity that increases risk of
  cardio-respiratory depression with sedatives is
  significant
• CHF, neuromuscular disease
• COPD, dehydration
• Anemia

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PATIENT SELECTION

• Who is not a candidate?
• Language barrier
• History of problems with previous anesthesia
• Known or suspected difficult ventilation or
  difficult intubation
• No person to accompany them home

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PREPARATION

• Do you have informed consent?
• Is patient aware of risks and the limitations?
  Have they been given alternative choices to
  procedure? Have questions been answered?
• What is the NPO status?
• Risks versus benefits
• Machine and drug check?
• Drugs and antagonists
• Emergency equipment available and checked?
• Defibrillator and skills of use

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ASPIRATION RISK

• Fasting pre-procedure decreases risks during
  moderate sedation and strongly decreases risks
  during deep sedation
• ASA guidelines recommend if procedure is elective
  fasting guidelines should be as for GA
• If not met then consider delaying procedure,
  reducing sedation level or ETT
• If emergency then may have to reconsider approach

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SUMMARY OF ASA PRE-PROCEDURE FASTING GUIDELINES
INGESTED MATERIAL MINIMUM FASTING PERIOD
Clear liquids 2 hours
Breast milk 4 hours
Infant formula 6 hours
Nonhuman milk 6 hours
Light meal 6 hours
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EQUIPMENT

• Dedicated qualified personnel
• Must be uninterrupted and continuous presence
• IV access
• Airway adjuncts
• Bag valve mask, oral and nasal airways, equipment
  for endotracheal intubation
• Suction for secretions

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MONITORING

• Does monitoring level of consciousness decrease
  risks of complications when administering
  procedural sedation?

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MONITORING

• Maintain verbal contact with patient
• Blood pressure, heart rate, respiratory rate
  measured at regular intervals
• Oxygen saturation, cardiac rhythm and ETCO2
  should be monitored continuously

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MONITORING

• Monitor patients response to medication and
  procedure
• Level of alertness, depth of respiration and
  response to painful stimuli all determine
  subsequent dosing

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MONITORING

• Supplemental oxygen often recommended to maintain
  oxygen reserves and prevent hypoxemia
• May delay recognition of hypoventilation
• ETCO2 monitoring useful
• Brief episodes hypoxemia and hypoventilation may
  occur clinical significance?

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TECHNIQUES

• Technique will vary from patient to patient
• Dosing of analgesics and anxiolytics vary widely
• Dosing depends on procedure as well as the
  anxiety of the patient
• Comfort measures contribute to reducing anxiety
  and pain

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TECHNIQUES

• Anxiety may be reduced by other methods than
  pharmacological
• Preoperative explanation of the procedure
• Calm and reassuring manner
• Quiet atmosphere with appropriate music
• Comfortable room temperature or warm blankets

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AGENTS USED

• Ideal drug has rapid onset of action and short
  duration of action, will maintain hemodynamic
  stability and have no side effects
• No single drug available with all of these
  features

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AGENTS USED

• Anxiolytics
• Benzodiazepines
• Diazepam, midazolam, lorazepam
• Benzene ring fused to diazepine ring
• All highly lipophilic
• Highly protein bound
• All absorbable after po administration

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MIDAZOLAM

• Midazolam most commonly used
• Rapidly enters CNS then redistributed
• Works through GABA pathways
• Distribution of GABA receptors restricted to CNS
• Minimal effects outside of CNS
• Most important clinical effects
• Sedative-hypnotic
• Amnestic
• Anxiolysis
• Anti-convulsant
• No analgesia

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MIDAZOLAM

• Favorable side effect profile
• Minimal depression of ventilation
• May cause mild ?BP esp in hypovolemic patient
• Synergistic with narcotics
• Combo may cause severe respiratory depression
• Antagonist available Flumazenil
• Dosage 10 to 25 µcg/kg q 3 to 5 minutes

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AGENTS USED

• Propofol
• Phenol derivative, highly lipophilic
• Can be painful on injection
• Rapidly metabolized in liver with high plasma
  clearance
• Onset within 40 seconds with duration 8 - 10
  minutes
• Causes peripheral vasodilatation
• ? BP more pronounced with ? age , ?
  intravascular volume or with rapid injection

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PROPOFOL

• Potent respiratory depressant with ? doses
• ?MV through ?TV and RR
• Has anti-emetic effects
• Sedative and amnestic not analgesic
• No reversal agent
• Difficult to titrate in some cases, can cause
  very deep sedation

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PROPOFOL

• Dosage unchanged if renal or liver impairment
• Metabolism appears to be slower in elderly
• Reduce doses by 20 and increase dosing interval
• 100 to 500 µcg/kg every 3 to 5 minutes bolus
• Continuous infusion 25 to 100 µcg/kg/min
• May require addition of short acting opioids due
  to absence of analgesic activity. This increases
  risk of respiratory complications

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KETAMINE

• Highly lipid soluble derivative phencyclidine
• Rapid onset of action
• Use limited by side effects
• Dreams, halllucinations, out of body experiences
• Significant cardiovascular effects
• Sympathomimetic ?BP, HR, CO
• Minimal respiratory depression
• Bronchodilatation

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KETAMINE

• Profound analgesia
• Multiple routes of administration
• May supplement inadequate regional anesthesia
• 50 to 100 mcg/kg usual single dose
• No more than 10 mg/hour to avoid side
  effects

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PENTOTHAL

• IV barbiturate, induction agent
• Hypnotic, sedatives, anticonvulsants
• Undergoes hepatic metabolism
• Recovery after bolus comparable to propofol
  because of redistribution to inactive tissue
  sites
• Even single boluses can lead to psychomotor
  impairment for several hours

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PENTOTHAL

• CNS depressant
• Anti-analgesic properties
• May reduce pain threshold
• ?BP due to peripheral vasodilation
• Transient as compensatory ? HR
• Respiratory depressant
• ? TV and ? RR transient apnea

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ETOMIDATE

• IV anesthetic with minimal hemodynamic effects
• Hypnotic but no analgesic properties
• Rapid onset of anesthesia almost immediate -
  with minimal changes in HR and CO
• Usual dosing 0.1 to 0.15 mg/kg IV for PSA
• Causes adrenocortical suppression so not widely
  used
• Myoclonus also seen frequently

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AGENTS USED

• Miscellaneous agents
• Chloral hydrate
• Pentobarbital
• Methohexital
• Dexmedetomidine
• Local anesthetics
• May reduce doses of sedatives and narcotics
• Useful as co-analgesics

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OPIOIDS

• High degree of variability in dose response
• Inter-individual variation
• Analgesia, euphoria, sedation, ? concentration
• Clearance primarily hepatic metabolism
• May be active metabolites

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SIDE EFFECTS

• Cardiovascular
• May produce orthostatic hypotension
• Respiratory
• Dose dependent depression of ventilation
• Decreased responsiveness to CO2
• May persist for several hours
• Apnea
• CNS
• Do not reliably produce unconsciousness
• Skeletal muscle rigidity

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SIDE EFFECTS

• Sedation
• Nausea and vomiting
• Direct stimulation CRTZ dopamine receptors
• Biliary tract
• Spasm of biliary smooth muscle
• May be confused with angina

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AGENTS USED

• Fentanyl
• Synthetic opioid structurally related to
  meperidine (phenylpiperidine derivative)
• 75 to 125 times more potent than morphine
• More lipid soluble than morphine crosses BBB
• Short acting with rapid redistribution to tissue
• Clinically rapid onset (2 to 3 minutes)
• No amnestic properties

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FENTANYL

• Primary side effect is respiratory depression
• Will potentiate sedative effects of other drugs
• Wide range of doses
• 0.25 to 0.5 µcg/kg q 3 to 5 minutes
• 1 to 2 µcg/kg for analgesia
• With multiple bolus doses or continuous infusion
  the duration of action is prolonged

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ALFENTANIL

• 1/5 to 1/10th potency fentanyl
• More rapid onset and shorter duration
• 1.4 minutes
• May be useful for retrobulbar blocks
• 10 fold inter-individual variation in dosing
• 0.1 to 0.4 µcg/kg/min by infusion

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REMIFENTANIL

• Unique because of ester linkage and metabolism by
  plasma esterases
• Short acting, titratable, rapid onset and offset,
  rapid recovery after infusion
• Boluses excellent for short painful procedures
• Doses 0.25 to 1 µcg/kg
• Infusions for sedation
• Doses 0.05 to 0.2 µcg/kg/min

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TECHNIQUES

• May be by intermittent bolus or by continuous
  infusion
• Target controlled infusions
• Plasma levels
• Effect site levels

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TECHNIQUE

• Monotherapy may be desirable
• Short acting drugs may be desirable
• Onset of action
• Small increments
• If synergistic action reduce to ¼ usual dose
• Antagonists readily available

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TECHNIQUE

• Sedation and inadequate block
• Surgeon may have to supplement if block is
  inadequate
• Duration of surgery may exceed duration of local
  anesthetic
• Restlessness and hypoxia
• Consider in differential diagnosis

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TIPS

• If elderly or co-morbid disease then may be more
  conservative with approach
• Start with lower dose
• Administer meds more slowly
• Be aware of slower circulation times
• Redose at less frequent intervals

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TIPS

• NEVER BE AFRAID TO CALL FOR HELP

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COMPLICATIONS

• Serious complications rare
• All sedatives and narcotics will cause adverse
  reactions in some patients even within
  recommended doses
• Extremes of age most at risk
• Most sedatives cause dose dependent respiratory
  depression
• Risk of desaturation up to 11 with propofol,
  even with supplemental oxygen
• Hypoventilation and apnea usually easily treated

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COMPLICATIONS

• Treat respiratory complications with patient
  stimulation, oxygen, airway positioning or brief
  ventilatory support
• Cardiovascular instability uncommon
• More likely to occur if significant cardiac
  morbidity
• Hypotension and bradycardia may develop in
  patients on CV depressants
• Usually transient

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COMPLICATIONS

• Vomiting
• Seen in approximately 5 PSA
• More common if narcotics given
• Little evidence regarding prophylaxis
• Inadequate sedation preventing completion of
  procedure
• Over sedation
• Agitation
• Allergic reactions

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COMPLICATIONS

• Inadequate evaluation
• Inadequate monitoring
• Inadequate practitioner skills
• Premature discharge

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RECORDS

• Vital signs and level of consciousness
• Document at baseline
• Regular, frequent intervals during the procedure
• Regular, frequent intervals during recovery
• Prior to discharge

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RECOVERY PERIOD

• Requires monitoring as during procedure
• Patients may be at increased risk after removal
  of painful stimulus
• What is ideal length of recovery period?
• Various criteria available such as Aldrete
• Consciousness Activity
• Respiration Saturation
• Circulation
• Consider pain and nausea

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DISCHARGE CRITERIA

• Fully conscious
• Respond appropriately
• Walk unassisted
• Baseline vital signs
• Pain, nausea and vomiting, bleeding all under
  control
• Must have accompanying responsible person

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AFTERCARE

• Responsible accompanying person for 24 hours
• Written detailed instructions for dealing with
  complications
• Medical assistance readily available
• Should be contacted next day by phone
• No major life decisions, driving or alcohol for
  24 hours

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REFERENCES

• Practice Guidelines for Sedation and Analgesia by
  Non-Anesthesiologists - ASA
• Basics of Anesthesia 5th edition - Stoelting

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CLINICAL SCENARIOS

• You are asked to provide sedation for cataract
  surgery to an 80 year old male. He has a history
  of controlled hypertension. NKDA. Medications
  Atenolol 50 mg bid
• Any concerns? What would you choose for sedation
  for this patient?

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• The procedure finishes and you bring the patient
  back to the PACU in stable condition. 15 minutes
  later you receive a call that your patient is no
  longer responsive
• What is your differential diagnosis?
• How do you approach the management?

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• You are monitoring a 62 year old patient under
  spinal anesthesia for a total knee replacement
  when she suddenly becomes bradycardic - HR drops
  to 45 (from 70)
• What are your first steps?
• What treatment would you give if any?

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• You are in the endoscopy suite providing sedation
  for colonoscopy. Your patient is a 50 year old
  for routine screening with no significant past
  medical history. 10 minutes into the procedure
  BP drops to 100/60 from baseline 135/72
• Any concerns?

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• You are monitoring a 73 yo male under SAB who is
  undergoing TURP. One hour into the procedure he
  is becoming increasingly restless. You give 1 mg
  midazolam IV. He becomes more confused and pulls
  out his IV
• Differential??