Procedural Sedation

last authored: Dec 2009, David LaPierre

 

 

Introduction

 

 

 

 

Rapid Sequence Intubation

Rapid sequence intubation (RSI) refers to the sedation and paralysis prior to an intubation procedure. The technique is a quicker form of the process normally used to "induce" a state of general anesthesia.

 

The difference between an RSI and standard anaesthetic intubation is that the anaesthetist does not wait to see the effect of the drugs.

 

Medications are utilized to allow rapid placement of an endotracheal tube between the vocal cords, while the cords are being visualized with the help of a laryngoscope.

 

The neuromuscular blocking agents paralyse all of the patient's skeletal muscles, most notably and importantly in the oropharynx, larynx, and diaphragm. Once the endotracheal tube has been passed between the vocal cords, a cuff is inflated around the tube in the trachea and the patient can then be artificially ventilated.

 

RSI involves pre-oxygenating the patient with a tightly-fitting oxygen mask, followed by the sequential administration of pre-determined doses of a hypnotic drug and a rapid-acting neuromuscular blocker.

 

Hypnotics used include thiopental, propofol and etomidate.

 

Neuromuscular-blocking drugs used include suxamethonium (sometimes with a defasciculating dose of vecuronium) and rocuronium.

 

Other drugs may be used in a "modified" RSI.

 

When performing endotracheal intubation, there are several adjunct medications available. No adjunctive medications, when given for their respective indications, have been proven to improve outcomes.

 

Opioids such as alfentanil or fentanyl may be given to attenuate the responses to the intubation process (tachycardia and raised intracranial pressure).

 

This is supposed to have advantages in patients with ischemic heart disease and those with brain injury (e.g. after traumatic head injury or stroke).

 

Lidocaine is also theorized to blunt a rise in intracranial pressure during laryngoscopy, although this remains controversial and its use varies greatly.

 

Atropine may be used to prevent a reflex bradycardia from vagal stimulation during laryngoscopy, especially in young children and infants.