Ketamine

Question 1

Presentation

Answer 1

200 mg in 2 mL ampoule

Question 2

Pharmacology

Answer 2

Rapid acting dissociative anaesthetic agent (primarily an NMDA receptor antagonist)

Question 3

Pharmacology - Actions

Answer 3

Produces a dissociative state characterised by:

A trance-like state with eyes open but not responsive
Nystagmus
Profound analgesia
Normal pharyngeal and laryngeal reflexes
Normal or slightly enhanced skeletal muscle tone
Occasionally a transient and minimal respiratory depression

Question 4

Metabolism

Answer 4

Metabolised = liver
Excreted = kidneys

Question 5

Indications

Answer 5

Rapid sequence intubation
Extreme traumatic pain refractory to opioid analgesia
Extreme agitation
CPR interfering patient

Question 6

Contras

Answer 6

Known hypersensitivity
Severe hypertension (SBP > 180)

Question 7

Precautions

Answer 7

Any condition where significant elevation of BP would be hazardous. eg:
Hypertension
CVA
Recent AMI
CCF

For analgesia - inject slowly over 1 min to minimise risk of respiratory depression and hypertension

Question 8

Route of administration

Answer 8

IV
IO
IM

Question 9

Side effects - Cardiovascular

Answer 9

Increase in BP

Increase in HR

Question 10

Side effects - CNS

Answer 10

Respiratory depression or apnoea
Emergence reactions (nightmares, restlessness, vivid dreams, confusion, hallucinations, irrational behaviour)
Enhanced skeletal tone
Nausea and vomiting

Question 11

Side effects - Ocular

Answer 11

Diplopia and nystagmus with slight increase in intraocular pressure

Question 12

Side effects - Other

Answer 12

Local pain at injection site
Lacrimation
Hypersalivation

Question 13

Special notes

Answer 13

Emergence reactions, hallucinations or other behavioural disturbances associated with Ketamine administration for analgesia in adult patients may be managed with Midazolam (ALS consult only) 0.5-1 mg.

Consult with RCH to administer Midazolam in paediatric pts.

Hypersalivation may be managed with suctioning, or in severe cases IV or IM Atropine (MICA only)

Question 14

IV effects

Answer 14

Onset = 30 secs
Peak = N/A
Duration = 10 mins

Question 15

IM effects

Answer 15

Onset = 3-4 mins
Peak = N/A
Duration = 12-25 mins

Question 16

Extreme traumatic pain - Adult

Answer 16

ALS consult only

Extreme traumatic pain persists despite opioid therapy
Consider Ketamine 10-20 mg IV @ 5-10 min intervals

Severe procedural pain
Consider Ketamine 20-30 mg IV @ 2 min intervals

Question 17

Preparation for Analgesia administration

Answer 17

200 mg in 2 mL
Dilute with 18 mL Normal Saline into a 20 mL syringe
= 10 mg in 1 mL

Question 18

Extreme traumatic pain - Peadiatric

Answer 18

MICA only

Extreme traumatic pain persists despite opioid therapy
Consider Ketamine 0.25 mg/kg IV @ 5-10 min intervals
Max 0.5 mg/kg

Question 19

Severe agitation

Answer 19

SAT score +3
"Combative, violent, out of control"
"Continual loud outbursts"
< 60 kg = 200 mg IM
60-90 kg = 300 mg IM
> 90 kg = 400 mg IM

Consult for further ketamine if required

If pt is hyperthermic or increased muscle tone, consult clinician for Midazolam 2.5-5 mg IV, max 20 mg