Anesthesia, Analgesia, Anxiolysis, Amnesia, And so on…

Ivy Pointer, M.DPediatric Critical Care FellowUNC Department of Anesthesiology

Overview

Role of sedation in critical care Elements of sedation Levels of sedation Choosing a sedation plan Choosing the right drug Preventative medicine

Sedation in Critical Care

Medical illness Post-operative care Diagnostic imaging Invasive procedures Mechanical ventilation

Elements of Sedation

Anesthesia Analgesia Anxiolysis Amnesia

Anesthesia

Definition Loss of sensation & loss of

consciousness Examples (Intravenous anesthetics)

Etomidate Ketamine Propofol Thiopental

Analgesia Definition

Inability to sense pain Examples

Non-sedating Analgesics Lidocaine/L.M.X. 4 Acetaminophen NSAIDs (Ibuprofen, Ketorolac)

Sedating Analgesics Narcotics (Fentanyl, Morphine, Oxycodone,

Methadone) Ketamine

Anxiolytics

Definition Relief of apprehension, fear, and/or

agitation Examples

Benzodiazepines (Midazolam, Lorazepam, Diazepam)

Chloral Hydrate

Amnestics

Definition Loss of memory, inability to recall

events Examples

Benzodiazepine Ketamine

Levels of Sedation

Awake Moderate Sedation

Deep Sedation

General Anesthesia

Moderate Sedation

Purposeful response to verbal stimulation

Airway patent Spontaneous ventilation adequate Cardiovascular function unaffected

Deep Sedation

Difficult to arouse Purposeful response only to painful

stimulation Airway may be obstructed Spontaneous ventilation may be

impaired Cardiovascular function usually

unaffected

General Anesthesia

Loss of consciousness Positive pressure ventilation Cardiovascular function may be

affected

Choosing a Sedation Plan

Remember mnemonic AMPLE!! A llergies M edications P ast Medical History L ast Meal E vents leading to sedation

Allergies

Drug allergies Environmental allergies

Egg & soy allergy no Propofol Contrast allergies

Medications

Knowing current medications & therapeutic interventions can help tailor your sedation plan… Sedatives already being used Vasoactive medications Neuromuscular blockers Respiratory medications Hemofiltration/dialysis And so on…

Past Medical History

Know current patient problem list and significant past medical/surgical history Respiratory (hypoxia, pneumothorax) Cardiovascular (hypotension,

myocardial dysfunction) Neurologic (increased ICP, seizure

disorder) Hepatic/Renal failure

Past Medical History

Past history of sedation Medications used in the past Prior adverse events with sedation Ability to manage airway (Pierre Robin,

croup, mediastinal mass, prior radiation, asthma)

Family history of problems with sedation

Past Medical History

ASA Physical Status Score ASA I : normally healthy patient ASA II: mild systemic disease ASA III: severe systemic disease ASA IV: severe systemic disease that is

a constant threat to life ASA V: moribund patient not expected

to survive without operation

Physical Exam

Mallampati/Samsoon Classification Class I: soft palate, uvula, pillars Class II: soft palate, portion of uvula Class III: soft palate, base of uvula Class IV: hard palate only

Other predictors of difficult airway Obesity with short neck Reduced neck movement Inability to protrude the lower teeth Reduced mouth opening Receding mandible Thyromental distance of less than 3 fingers

Last Meal

Full stomach is a risk of aspiration during sedation!!!

NPO status Last solid intake > 6 to 8 hours Last opaque liquid/formula intake > 4 hours Last clear liquid/breastmilk intake > 2 hours

These guidelines do not apply for patients with GI disturbances

Last Meal

Full stomachs include the following… Any patient with material in their stomach

Food Medications Contrast Charcoal Blood

Any patient with delayed gastric emptying Morbid obesity Small bowel obstruction Pyloric stenosis GI dysmotility And so on…

Events leading to sedation…

Know why your patient needs sedation!!

Is it safe to sedate your patient?? What kind of sedation are you trying

to achieve?? Analgesia, anxiolysis, amnesia, or a

combination Anticipated duration of therapy

Choosing the Right Drug

There is no magic cocktail…all drugs have potential complications

Drugs to consider should fit your goals for sedation with minimum risk to the patient

Considerations when choosing a drug Route of administration Onset of action Duration of action Contraindications Therapeutic advantages

Our favorite PICU drugs

Anesthetics: Propofol, Ketamine, Pentobarbital

Analgesics: Fentanyl, Morphine

Anxiolytics: Midazolam, Lorazepam, Diazepam

Other: Dexmedetomidine, Clonidine

Propofol

Onset: 30 sec Duration: 3-10 min Dose: 1 mg/kg

Infusion: 50-150 mcg/kg/min Disadvantages: respiratory

depression, hypotension, bradycardia, NO analgesia, metabolic acidosis with prolonged infusion

Ketamine

Onset: 30 sec (IV), 3-4 min (IM) Duration: 5-10 min (IV), 12-25 min (IM) Dose: 0.5-1 mg/kg (IV), 4-5 mg/kg (IM)

Infusion: 5-20 mcg/kg/min Analgesia and amnesia

preserves upper airway tone and reflexes Disadvantages: excess secretions,

increased ICP, emergence reaction

Pentobarbital

Onset: 3-5 min (IV) Duration: 15-45 minDose: 1-2 mg/kgDisadvantages: NO reversal agent,

no analgesia (enhances pain perception)

Fentanyl

Onset: 2-3 minDuration: 30-60 minDose: 1 mcg/kg100x more potent than morphineAvailable reversal agent

NaloxoneDisadvantages: no amnesia/

anxiolysis, “steel chest”

Morphine

Onset: 5-10 min (IV) Duration: 4-6 hours Dose: 0.05-0.1 mg/kg Available reversal agent:

Naloxone Disadvantages: no amnesia/

anxiolysis, histamine release

Onset: 2-6 min Duration: 45-60 minDose: 0.05-0.1 mg/kgAvailable reversal agent

FlumazenilRetrograde amnesiaDisadvantages: NO analgesia,

paradoxical reactions

Midazolam (Versed)

Diazepam (Valium)

Onset: 1-1.5 hours (oral) Duration: variable but LONG (oral) Dose: 0.1-0.8 mg/kg/day (oral) Useful for tapering Disadvantages: accumulation, long

half-life, avoid rapid IV push

Lorazepam (Ativan)

Onset:15-30 min (IV) Duration: 3-4 hours (up to 12 hrs) Dose: 0.05-0.1 mg/kg Disadvantages: mixed with

propylene glycol Anion gap metabolic acidosis, osmolar

gap Avoid infusions

Dexmedetomidine (Precedex)

IV alpha-2 agonist 1700x more selective for alpha 2

Onset: 15-30 min Duration: 60-120 min Dose: load with 0.5-1 mcg/kg

Infusion of 0.3 – 1.5 mcg/kg/hr Disadvantages: bradycardia, only

approved for 24 hr infusions

Clonidine

Centrally acting alpha-2 agonist Onset: 30-60 min (oral) Duration: 6-10 hours Dose: 0.05 mg/day (oral) Can convert to transdermal patch Eases withdrawal & decreases

anesthetic requirements

Contraindications

All drugs should be used judiciously!!! Commonly seen relative contraindications

and adverse effects Ketamine increased ICP, excess salivation,

emergence reaction Propofol hypotension, acidosis Dexmedetomidine bradycardia, arrhythmia Benzodiazepine hypotension

Therapeutic Advantages

Not all side effects are harmful Considerations for choice of drug

Ketamine bronchodilator Pentobarbital or Midazolam anti-

convulsant Diazepam muscle relaxation

Cases

Case #1

An 8 year old known asthmatic is in the ED having received continuous albuterol nebs, steroids, and subcutaneous epinephrine. You check on him and find him unresponsive with a RR of 6 and very poor air movement. An RT runs in with a ABG showing pH 6.9, pCO2 190. What medications do you consider for intubation & sedation?

Case # 2

A transport team has just arrived to pick up a 4 year old child with severe stridor. On exam she is alert, sitting in Mom’s lap & maintaining her sats, but has severe retractions with every breath and drooling. She appears frightened, and the paramedic asks you to order something to sedate her so that she can be strapped to the gurney. What is your response?

Case # 3

You consult in the ED on a 7 year old who has presented with sore throat and noisy breathing. He has received 2 gm of chloral hydrate 1/2 hour before for an attempted CT scan of the neck. In the ED you find him in the back room with his mother, with a sat probe on his finger not attached to a monitor. He has retractions and poor air movement with every breath. What happened and what would you do?

Case # 4

You are taking care of a 9 mo post-op cardiac patient who is intubated and requiring sedation. She initially had issues with heart block and required pacing but is now in a sinus rhythm of 110. She has been difficult to sedate with Fentanyl & Midazolam and the nurses ask you if you can add a 3rd agent. What agents would you want to avoid in this patient and what do you need to consider?

Case # 5

You are called to the ED to see a 6 year old trauma patient who luckily has a normal head CT but unfortunately has a severely displaced tib-fib fracture. The orthopedic surgeons are gathering equipment to reduce and splint the fracture. What drugs do you think about using and what else do you consider?

Preventative Medicine is Key!!

Optimize your patient prior to sedation Correct acidosis Keep euvolemic Know “AMPLE”

Anticipate difficulties and be prepared Bag, mask, oxygen, +/- airway box Suction Normal saline/Lactated Ringer’s Monitors – O2, CO2, CR monitor, BP

Titrate medications to effect…it is easier to give more drug than it is to remove it!!!

Summary

Many situations require sedation in the ICU Components of sedation include anesthesia,

analgesia, anxiolysis, & amnesia There are several levels of sedation Remember mnemonic “AMPLE” when evaluating a

patient for sedation Choosing the right drug involves knowing the

goals of sedation alongside drug profile for sedatives

Always anticipate possible complications & be prepared to deal with them