Conscious Sedation

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Conscious Sedation

• Timothy Sauvage
• CRNA, MS, ARNP

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• The goal of conscious sedation is to produce a
  state where
• Patients are able to tolerate unpleasant
  procedures
• Adequate cardio-respiratory function is
  maintained
• Patients are able to respond purposely to verbal
  commands and or tactile stimulation

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• The ASA practice guidelines for conscious
  sedation by non-anesthesiologists state that
  conscious sedation should result in a patient who
  is lightly sedated, cooperative on demand,
  amnesic, and free from pain and anxiety.

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• The JCAHO defines conscious sedation as,
  moderate sedation/analgesia
• It also states that the patient should be able to
  respond purposely to verbal commands, either
  alone or accompanied by light tactile
  stimulation.
• It further states that no further interventions
  are required to maintain a patients airway, that
  spontaneous ventilation is adequate, and that
  cardiovascular function is usually maintained.

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Patient Evaluation

• A patient history , physical examination
  including height, weight, assessment of airway
  patency, auscultation of the lungs and heart, and
  laboratory evaluation based on the patient's
  underlying medical condition, all should be
  performed. the patient's medical history should
  include

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• All current medications and drug allergies
• Meperidine (demerol) is contraindicated in a
  patient taking monomine oxidase inhibitors
  (maoi), discontinue the maoi two weeks before
  administration of demerol.
• Opioids (fentanyl) and CNS depressants can
  increase the potential for apnea and
  over-sedation when administered with a
  benzodiazepam (versed)

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• Diazepam clearance and not midazolam is decreased
  and its half-life increased with cimetidine
• Indinavir and saquinavir may inhibit the
  metabolism of midazolam and increase the
  potential for prolonged sedation
• Ritonavir can greatly increase the plasma
  concentration of midazolam, diazapam, and
  meperidine and therefore should not be used in a
  patient taking ritonavir

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• Previous adverse effects to conscious sedation
• Time and nature of last oral intake
• clear liquids greater than 2-3 hours
• solids greater than 6-8 hours
• History of alcohol, tobacco, and illicit drug use
• Any abnormalities of major organ function

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Airway Evaluation
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Airway Evaluation

• Airway examination should always include
• Overall Appearance
• Mouth
• Movement
• Palpation
• Nose

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Overall Appearance

• Neck
• stout or thin?
• long or short?
• Sunken cheeks?
• Presence of a beard may make fitting the mask on
  the face difficult.

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Mouth

• Mouth opening (measured in cm or fingerbreadth)
• Anterior displacement of mandible
• Tongue size
• Visibility of uvula
• Protrusion of upper incisors
• Loose or damaged teeth prostheses

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Movement

• Flexion/extension of neck
• Sniffing position

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Palpation

• Trachea in midline
• Distance from mentum to hyoid

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Nose

• Both nares patent
• Protuberant nose suggests poor mask fit and
  difficult mask ventilation.

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Size of tongue in relation to the size of the
oral cavity
This test is performed with the patient in the
sitting position, the head held in a neutral
position, the mouth wide open, and the tongue
protruding to the maximum.
(Malampati Classification)
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Malampati Classification (mod.)

• Class 1
• Soft palate
• Fauces
• Uvula
• Anterior and posterior faucial pilars can be
  seen.

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• Class 2
• Soft palate
• Fauces
• Uvula can be seen
• The tongue masks anterior and posterior faucial
  pillars.

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• Class 3
• Soft palate
• Base of uvula can be seen only

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• Class 4
• Only hard palate is visible

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Laryngoscopic View

• 4 grades

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• Grade I
• Visualization of entire laryngeal aperture.

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• Grade II
• Visualization of only posterior portion of the
  laryngeal aperture.

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• Grade III
• Visualization of only the epiglottis.

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• Grade IV
• Visualization of only the soft palate.

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Atlanto-occipital joint extension

• The alignment of the oral, pharyngeal, and
  laryngeal axes into a straight line (sniffing
  position).
• This will allow less of the tongue obscuring the
  laryngeal view and there will be much less need
  for displacing the tongue anteriorly.

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Thyro-mental distance

• The space anterior to the larynx determines how
  readily the laryngeal axis will fall in line with
  the pharyngeal axis when the atlanto-occipital
  joint is extended.
• When there is a large mandibular space, the
  tongue is easily contained within this large
  compartment and does not have to be pulled
  maximally forward in order to reveal the larynx.
• The distance between inside the mandible to hyoid
  bone should be greater than 6 cm or 3
  fingerbreadths.
• NECK
• Neck examination should be performed as part of
  airway evaluation. Presence of carotid bruit,
  midline masses which can deviate or compress the
  trachea.

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Predictors of a Difficult Airway

• Short muscular neck
• Prominent upper incisors
• Protruding mandible
• Receding mandible
• Small mouth opening
• Full beard
• Large tongue
• Limited neck mobility
• Limited mouth opening due to TMJ

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Short muscular neck
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Prominent upper incisors
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Protruding mandible
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Receding mandible
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Small mouth opening
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Full beard
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Large tongue
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Limited neck mobility
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Limited mouth opening due to TMJ
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Summary of Airway Evaluation

• A thorough assessment of your patients anatomy
  will provide you the knowledge necessary to
  perform safe, conscious sedation.
• It is the lack of preparation
  and understanding that often
  makes the simplest sedation,
  the one most difficult to
  perform.

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Conscious Sedation Drugs

• Fentanyl
• Versed
• Propofol
• Demerol
• Morphine
• Lidocaine

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Fentanyl

• Uses
• Sedation, relief of pain
• How does it work
• Binds to opioid receptors throughout the CNS
  (this includes the respiratory center in the
  brain)
• Once bound it opens potassium channels and
  inhibits calcium channels from functioning.
• This receptor activity results in an increase in
  pain threshold, alters pain perception, and
  inhibits pain to travel to the brain and be
  recognized.
• Remember The respiratory depression of the drug
  may last longer than the analgesic effect.

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• Dosing
• I.V., onset of the drug is 7 to 15 minutes and
  will last 30 to 60 minutes
• Distribution
• Distributes to muscle and fat, highly lipophilic
• Metabolism
• Liver
• Usual dosing
• Titration, titration, titration, to appropriate
  response and desired degree of conscious sedation
• Initial I.V. dose 25-50 mcg and then titrate
  upward. pump infusion would range 1-3 mcg/kg/hr

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• Adverse reaction
• ( gt10) bradycardia, hypotension, vasodilatation
• (lt10) apnea, post procedure respiratory
  depression
• Ethanol
• Avoid ethanol due to the fact it may increase CNS
  depression
• Herbs
• St. John's wort may decrease fentanyl levels,
• Avoid valerian, St. John's wort, kava kava, gotu
  kola (may decrease CNS depression)

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Versed (Midazolam)

• Uses
• Preoperative sedation and provides conscious
  sedation prior to diagnostic or radiographic
  procedures, ICU sedation, and anesthesia delivery
• How does it work
• Depresses the CNS by binding to the
  benzodiazepine site on the GABA receptor
  modulating GABA activity.
• GABA is the major inhibitory neurotransmitter in
  the brain

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• Dosing
• The dose of midazolam needs to be individualized
  based on the patient's age, underlying diseases,
  and concurrent medication.
• Decrease the dose by 30 if narcotics or other
  CNS depressants are administered together.
  Personnel and equipment needed for standard
  respiratory resuscitation should be immediately
  available during midazolam administration.
• Adult dosing for conscious sedation I.V. initial
  dose 0.5 - 2.0 mg given slowly over 2 minutes and
  titrating to desired effect and possibly
  repeating the dose slowly over 2-3 minutes.
  Medicate, wait, evaluate, re-medicate, and
  re-evaluate.
• If narcotics or other CNS depressants are
  administered concomitantly, the midazolam dose
  should be decreased by 30. Usual total dose of
  2.5-5.0, use decreased dosing in the elderly and
  rarely should you give greater than 3.5 mg total
• Distribution
• Will increase with congestive heart failure and
  renal failure
• Metabolism
• Liver

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• Adverse reactions
• (gt 10) respiratory, decreased tidal volume and
  or inspiratory rate decrease to apnea
• (lt 10) hypotension, dizziness, coughing
• Ethanol
• Avoid alcohol because of the CNS depression
• Herbs
• Avoid concurrent use with St. John's wort due to
  increase in CNS depression.
• Avoid concurrent use with valerian, kava kava,
  gotu kola, also due to CNS depression

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Propofol (Diprivan)

• Uses
• Monitored anesthesia care sedation, during
  diagnostic procedures, sedation for ICU patients
  on the ventilator provided they are at least 18
  years old
• How does it work
• The mechanism proposed is that it is GABA
  receptor mediated but the exact mechanism is
  unknown

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• Dosing
• Must be individualized based on total body weight
  and titrated to the clinical desired effect,
  wait at least 3-5 minutes between dosage
  adjustments to clinically assess drug effects,
  smaller doses are required when used with
  narcotics.
• For conscious sedation in the adult, initial
  dosing should be 100-150 mcg/kg/minute for three
  to five minutes or slow injection of 0.5 mg/kg
  over 3-5 minutes.
• For the debilitated/elderly doses should be
  decreased and titrated slowly to effect.
  maintenance of sedation, use variable rates 25-75
  mcg/kg/minute via infusion and incremental bolus
  doses 10-20 mg. in the debilitated patient you
  should decrease their dose by 20
• Distribution
• Large volume of distribution
• Metabolism
• Liver to water-soluble sulfate and glucuronide
  conjugates

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• Adverse reactions
• ( gt10) hypotension, burning at site of injection
  by using a large vein or a central vein, apnea
  episodes
• (lt10) hypertension, movement, itching,
  respiratory acidosis
• Drug interactions
• Central nervous system depressants additive CNS
  depression and respiratory depression may require
  dosage reduction when used with anesthetics,
  benzodiazepines, opiates, ethanol, and
  phenothiazines.
• Narcotics
• Concomitant use may lead to increased sedative or
  anesthetic effects of propofol, more pronounced
  decreases in systolic, diastolic, and mean
  arterial pressures and cardiac output. Pediatric
  patients receiving fentanyl may also become
  bradycardic with the addition of propofol.
• Theophylline
• May antagonize the effects of propofol and
  therefore, require more drugs be given.

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Demerol (Meperidine)

• Uses
• Management of moderate to severe pain adjunct to
  anesthesia and preoperative sedation
• How does it work
• Binds to opioid receptors throughout the CNS.
• When the drug binds to the receptor the effects
  are excreted by K channel opening and CA
  channel inhibition.
• This action will result in an increase in pain
  threshold, alter pain perception, and inhibit
  ascending pain pathways.

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• Dosing
• Doses should be titrated to the desired analgesic
  effect.
• Adults receiving I.V. Demerol will need 50-150
  mg/dose every 3-4 hours as needed.
• Distribution
• Crosses the placenta and appears in breast milk,
  highly protein bound
• Metabolism
• Liver, with liver disease the half life may
  increase to 11 hours which is approximately 3
  times longer

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• Adverse reactions
• Do not use with mao inhibitors presently or
  within 14 days, hypotension, fatigue, rash,
  dyspnea, phenytoin may decrease the analgesic
  effects
• Ethanol
• Avoid due to CNS depression,
• Herbs
• Avoid valerian, St. John's wort, kavaq kava, gotu
  kola
• may increase the CNS depression

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Morphine (morphine sulfate)

• Uses
• Relief of moderate to severe pain and chronic
  pain.
• How does it work
• Binds to opiate receptors in the CNS and exerts
  via K channel opening and inhibition of CA
  channels, causing inhibition of ascending pain
  pathways, altering the perception of and response
  to pain, produces generalized CNS depression

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• Dosing
• Should be titrated I.V. to effect.
• Do not mix routes of administration.
• I.V. dosing is 2.5-20 mg/dose every 2-6 hours as
  needed, usual 10mg/dose every 4 hours as needed.
  
• Continuous I.V. infusion 0.8-10mg/hr and may
  increase with pain, usual range is up to
  80mg/hour.
• Elderly and debilitated require less of the drug.
• Metabolized
• in the liver

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• Adverse reaction
• flushing, CNS depression, drowsiness, sedation,
  dependence
• (gt10) hypotension, drowsiness, pruritus, nausea,
  urinary retention, generalized weakness.
• (lt10) restlessness, visual problems, anorexia,
  respiratory depression.
• Ethanol
• Avoid any alcohol due to CNS depression
• Avoid CNS depressants, and antidepressants.
• Herbs
• Avoid valerian, St. John's wort, kava kava, gotu
  kola
• may increase CNS depression.

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Lidocaine

• Topical application for EGD should not be
  forgotten.
• Patients may gargle with 4 lidocaine and are
  then told to swallow it. If the patient still has
  a gag reflex after 10 minutes, then they may be
  orally sprayed with additional 4 lidocaine to
  get rid of the gag reflex.
• Is there a potential problem here?

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Drug Antagonists

• Narcan
• Flumazenil

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Narcan

• used for partial or total reversal of opioids
  depression, including respiratory depression.
• It does this by competing for the receptor that
  the narcotic is also seeking.
• The antagonist when it gets on the receptor site
  will remain there until it is metabolized and no
  longer functional.
• Onset
• When administered I.V., the onset is within two
  minutes and will last up to 60 minutes, but the
  narcan will wear off before the narcotic will and
  therefore will require additional dosing.

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• Dosing
• Adults I.V. 0.4-2 mg every 2-3 minutes as needed,
  may need to repeat dose every 20-60 minutes.
• Note use 0.1-0.2 mg increments in patients who
  are opioid dependent and in postoperative
  patients to avoid large cardiovascular changes.
  I.V. push should include all the drug
  incrementally injected over be
• Adverse reactions
• Patients may respond quickly and be in a state of
  confusion. Narcotic addicts may seize after
  receiving this drug.
• Remember, slow titration to effect and even then
  do not be surprised to see withdrawal symptoms in
  those patients who were addicted to narcotics.

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Flumazenil

• is a benzodiazepine antagonist that functions to
  reverse the sedative effects of the
  benzodiazepines.
• It is receptor specific and does not reverse
  narcotics, alcohol, or herbs. It blocks the
  benzodiazepine effect on the GABA benzodiazepine
  receptor.
• Onset
• is 1-3 minutes with 80 response in 3 minutes.
• The effect of the antagonist will not outlast the
  versed (benzodiazepine) and will require
  additional dosing.

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• Dosing
• Adult dosing for reversal of conscious sedation
  via I.V. route is an initial dose of 0.2 mg given
  over 15 minutes.
• If the desired level of consciousness is not met
  then repeat dosing of 0.2 mg may be given at 1
  minute intervals. In the event of re-sedation, 1
  mg doses may be repeated at 20 minute intervals
  with a maximum of 1 mg/dose and 3mg per hour.
• Adverse effects
• Nausea and vomiting, palpitations, headache,
  anxiety, tremor, hyperventilation, euphoria.
• Remember, slow titration to effect and you still
  may see symptoms of withdrawal.

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Summary of Sedation Drugs

• For all conscious sedation drugs
• Combination of opioids and sedatives may increase
  the incidence of adverse effects.
• When used together, each agent should be
  administered individually in order to allow the
  desired effect of each agent to be achieved.
• When given I.V., conscious sedation drugs should
  be administered in small, incremental doses until
  the desired effect is achieved (titrate to
  effect).

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• Care and patience must be taken to allow a
  sufficient time between doses to allow the effect
  of each dose to be seen.
• Dosage reductions may be required in the
  chronically ill or elderly as well as with the
  concomitant administration of an opioid and a
  sedative agent (benzodiazepine).
• Additional time should be allowed between doses
  when drugs are administered via nonintravenous
  routes secondary to the time required for drug
  absorption.

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• Monitoring requirements
• Drug administered
• Oxygen saturation
• Response to verbal commands
• Pulmonary ventilation
• Blood pressure and heart rate
• EKG
• ETCO2
• The above monitoring modalities should be
  recorded prior to the procedure, then every 5
  minutes throughout the procedure.
• If patient condition warrants taking vital signs
  more frequently, then do it.

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NPO Status

• Clear fluids - Can I see through it?
• Avoid for 2-3 hours prior to procedure
• black coffee
• hot tea
• ice tea
• apple juice
• cranberry juice
• grape juice
• plain jello
• sport drinks

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• Not clear fluids I can't see through it
• Avoid for 6-8 hours prior to procedure
• coffee with milk/cream
• hot tea with milk/cream
• orange juice with pulp
• tomato juice
• milk

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• Solid food
• Avoid for 6-8 hours prior to procedure
• coordinate with diabetics

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Past Trauma

• Dental work
• fractured jaw
• Motor vehicle accidents
• fractured nose, jaw, facial bones
• neck injuries leaving limited range of motion
  with flexion and extension
• Cancer radiation of neck /mandible
• Surgery
• radical neck
• cervical fusion
• jaw wiring
• Brain injury
• communication
• respiratory involvement
• Current medication
• opioids
• benzodiazepines
• NSAIDs
• aspirin

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Blood Tests (may not be necessary)

• Hemostasis
• INR 1-1.3
• Pt  20-40
• PTT lt 35 sec
• Bleeding Time, 3-8 minutes

PTT   Pt BT
Oral Coagulents     I/NC   I NC
Aspirin   NC     NC I
Heparin I I/NC NC
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Sleep Apnea

• Problem
• People stop breathing repeatedly during sleep due
  to physical blockage of the airway during sleep,
  this may occur hundreds of times per night and
  often for a minute or more.
• There are three different types of apnea
  central, obstructive, and mixed, of the three,
  obstructive is most common.

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• Treatment
• positioning - avoid supine
• weight loss
• avoid alcohol
• avoid CNS depressants
• oral bite block appliances
• surgery
• CPAP

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CPAP Application

• Works as a pneumatic splint by providing a flow
  of continuous positive air pressure through a
  nasal/nasal-oral mask to keep the airway open
  during sleep.
• This keeps the throat open and eliminates snoring
  and obstruction.

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Conclusion

• Complete history and physical
• Provide appropriate monitoring and special needs
  for patient
• Administer (titrate) medications in a timely,
  accurate manner
• Antagonist availability
• Appropriate lab work
• Be and feel prepared
• Evaluate, titrate, re-evaluate

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Questions?
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ETCO2
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