Ketamine

Question 1

Ketamine - Type

Answer 1

Anaesthetic agent

Question 2

Ketamine - Presentation

Answer 2

200mg in 2ml vial

Question 3

Ketamine - Actions (5)

Answer 3

1. Analgesic, sedative agent
2. Marked amnesia
3. Has bronchodilating properties
4. Does not tend to cause respiratory depression
5. Does not tent to cause hypotension (via sympathetic stimulation)

Onset IV 1-2 min, IM 3-5 min

Question 4

Ketamine - Uses (5)

Answer 4

1. Pain management, especially in pts who are hypotensive or unable to have narcotics, and if no other alternative is available
2. Particularly useful for trapped pts with limb injuries, especially if BP is borderline for narcotics
3. Adjunct to morphine, with alternating doses
4. Pharmacological intervention for combative/agitated pts, especially with suspected psycho-stimulant use
5. Sedation to manage airway, RSI, sedation of a previously intubated pt

Question 5

Ketamine - Adverse effects (6)

Answer 5

1. Transient laryngospasm
2. Hypersalivation
3. Emergence reactions
4. Muscle twitching and purposeless movements
5. Occasionally respiratory depression –> apnoea
6. Occasionally hypotension if given too rapidly to a hypovolaemic pt.

Question 6

Ketamine - Contraindications (3)

Answer 6

1. Known sensitivity
2. Active cardiac disease
3. Children

Question 7

Ketamine - Precautions (6)

Answer 7

1. Use with care in pts where a rise in BP may be hazardous
2. Known glaucoma
3. Previous psychoses
4. Hyperthyroidism
5. Elderly and paediatric pts
6. Pts previously administered narcotics

Question 8

Ketamine - Doses (pain management)

Answer 8

All doses up to listed and (IV) increments of 30-60 sec

Adult - IV 1mg/kg in 20mg increments, rep 5-10/60 as req

• IM 1mg/kg, rep after 5-10 as req
• IV previous opioids 10mg increments
• IM previous opioids 0.5mg/kg

>65 yrs - IV 1mg/kg in 10mg increments, rep 5-10/60 as req

• IM 0.5mg/kg, rep after 5-10 as req
• IV previous opioids 5mg increments
• IM previous opioids 0.25mg/kg

Paed >20kg - IV 1mg/kg in 10mg increments, rep 5-10/60 as req

• IM 0.5mg/kg, rep after 5-10 as req
• IV previous opioids 5mg increments
• IM previous opioids 0.25mg/kg

Paed <20kg - IV 1mg/kg in 5mg increments, rep 5-10/60 as req

• IM 0.5mg/kg rep after 5-10 as req
• IV previous opioids 2.5mg increments
• IM previous opiods 0.25mg/kg

Question 9

Ketamine - Doses (all except pain)

Answer 9

Combative/agitated pts

Adult & Paediatric - 1st line agent 4mg/kg IMI

• 2nd line agent 1.5mg/kg IV

IMI as single dose only, IV over 30 sec

With Suxamethonium

Adult - 1mg/kg IV fast push

Intubation when sux contraindicated

Adult - 2mg/kg IV fast push

Maintain sedation post intubation

Adult & Paediatric - 1mg/kg IV at 1-5min intervals titrated.

Question 10

Ketamine - Special notes

Answer 10

Can be used with alternating doses of morphine for analgesia only

Pts may still have significant awareness despite appearance of unconsciousness

Pts who become agitated may be managed with small repeat doses of midazolam

Question 11

Ketamine - recommended dilutions

Answer 11

Adult IV - 200mg to 10ml = 20mg/ml

Adult IM - 100mg to 2ml

Elderly IV - 100mg to 10ml = 10mg/ml

Elderly IM - 100mg to 2ml

Paed IV - 50mg to 10ml = 5mg/ml

Paed IM - 50mg to 2ml