In this episode, I’ll discuss the use of ketamine in status asthmaticus.
Because of its bronchodilator properties, the dissociative anesthetic ketamine is sometimes used as an adjunct in the treatment of status asthmaticus.
The doses reported have included boluses from 0.5 to 1 mg/kg and continuous infusions from 0.15 to 3 mg/kg/hr.
There is not a single recommended dose from a well-designed study for this indication. Even though ketamine should not affect the respiratory drive, I give consideration as whether the patient is on mechanical ventilation or not before deciding on a dose. My two main reasons for this are:
1. A patient who is using accessory muscles to breathe may stop using them if they are put into a dissociative state of anesthesia by a high dose of ketamine.
2. When pushed too fast, ketamine may cause a brief period of apnea which would be potentially catastrophic in a status asthmaticus patient if the team was not immediately prepared to intubate.
If the patient is already mechanically ventilated, a dose of 0.75 mg/kg IV bolus followed by an infusion of 0.75 mg/kg/hr is roughly the midpoint between published case report dosing.
If the patient is not yet intubated, I prefer subanesethetic dosing with a bolus of 0.5 mg/kg followed by an infusion at 0.15 to 0.5 mg/kg/hr.
Members of my Hospital Pharmacy Academy have access to practical training on the treatment of status asthmaticus and the use of ketamine in critical care from a pharmacist’s point of view, along with many other resources to help in practice. To get immediate access, go to pharmacyjoe.com/academy.
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