Ketamine for Induction
Use in the Prehospital Setting
Background
• Multiple drug shortages are threatening the safe
management of the most critically ill and injured
patients.
• Critical drugs such as etomidate, midazolam and
diazepam have at times not been available to some
of our EMS agencies.
Why Ketamine?
• Ketamine has long been used for procedural
sedation in the emergency department.
• More recently, concerns have been raised regarding
possible negative effects of adrenal suppression in
septic patients intubated using etomidate.
• Therefore, several studies as well as discussions in
the literature have since favorably reviewed the use
of ketamine for induction.
Mechanism of Action
• Ketamine is a dissociative anesthetic agent,
structurally similar to phencyclidine (PCP), which
interrupts the connection between the cortex and the
limbic system.
• Stimulates opiod receptors and is thus a unique
sedative agent in that it provides analgesia as well.
• Stimulates catecholamine release
• Increased BP, HR and cardiac output
• Bronchodilatation
Pharmacokinetics
• Onset of anesthesia when given IV is 30 to 60
seconds.
• The duration of the anesthetic effect is 5 to 10
minutes when given IV.
• The duration of drug effect following IV dosing can
last for hours. In this phase, the patient is responsive
but has varying degrees of delirium.
Indications
• Induction agent for rapid sequence intubation (RSI)
• At this time, ketamine should only be used as an
induction agent when the supplies of etomidate have
been exhausted.
• It is also used for procedural sedation and analgesia,
however it will not be approved for these uses by
EMS.
Precautions
• Ketamine should be used with caution in patients
with elevated blood pressures.
• Do not use ketamine in patients who may be in a
hypertensive crisis
• Patients emerging from the effects of ketamine may
experience disturbing nightmares and hallucinations.
Be sure to continue sedation after they are intubated
with another sedative agent.
Precautions
• May cause increased intraocular pressure and should
not be used when globe rupture is a concern.
• Increased ICP: This is controversial as several
studies have shown minimal increase in ICP. In fact,
an increase in CPP may actually be beneficial.
However, when increased ICP is suspected, it may
be beneficial to concomitantly give a dose of
midazolam 2 to 4 mg.
Drug Interactions
• There are no major drug interactions to avoid
Dosing
• The general induction dose is 2 mg/kg
• A range of 1 to 2 mg/kg is provided to allow for a
decrease in dose at the discretion of the medic, such
as in elderly patients.