cisatracurium besilate (Nimbex)
In patients with acute respiratory distress syndrome, it has been found that using a paralytic can increase the chance these patients have of survival. The main paralyzing agent that we use in my medical ICU is Nimbex. Patients are usually intubated on mechanical ventilation by this point. Patients can stack their breaths on the ventilator which decreases the ability of the ventilator to give the desired tidal volumes and oxygenation to the patient. In a sense, this makes it so that the patient cannot "buck the vent."
Nimbex allows the patient's diaphragm to be paralyzed and lets the ventilator do all the work. It gives the doctors the ability to adjust the ventilator (and the patient's breaths) to exactly what they need.
The generic name of Nimbex is cisatracurium besilate. It is a nondepolarizing skeletal muscle relaxant and is given intravenously. This blocks the neuromuscular transmissions at the neuromuscular junction which causes paralysis. It is a cis-isomer of atricurium and a cholinergic receptor agonist. The following pharmacokinetic information was provided by Medscape and is very important to keep in mind as you administer Nimbex (especially the half-life and that it is excreted in urine...remember that in case the patient is in kidney failure):
- Half-Life: 22-29 min
- Onset: 2-3 min (IV; mean for 0.15-0.2 mg/kg adult dose)
- Duration: 55-65 min
- Peak plasma time: 3-5 min
- Vd: 145 mL/kg
- Metabolism: Forms inactive metabolites
- Excretion: Urine 95%
Whenever you are paralyzing someone, you want to be absolutely sure that the patient is sedated first!! If you give the paralytic first, the patient will be literally frozen in their body unable to breath. Make sure they are sedated!! Sedation, then paralytic.
Before starting the administration of Nimbex, start by performing the train of four to get a baseline reading. In my experience with giving Nimbex, there is a loading dose that is administered first and then a continuous IV drip that is continued after that. These doses are determined based off of the patient's body weight. Work with your provider and pharmacy to titrate the dose per your hospital's protocol. We keep our dose the same for a set time period and then titrate after that based off of the train of four monitoring.
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