RSI meaning in Medical ?

In advanced airway management, rapid sequence induction (RSI) – also referred to as rapid sequence intubation or as rapid sequence induction and intubation (RSII) or as crash induction – is a special process for endotracheal intubation that is used where the patient is at a high risk of pulmonary aspiration. It differs from other techniques for inducing general anesthesia in that several extra precautions are taken to minimize the time between giving the induction drugs and securing the tube, during which period the patient's airway is essentially unprotected.

First described by William Stept and Peter Safar in 1970, "classical" or "traditional" RSI involves pre-filling the patient's lungs with a high concentration of oxygen gas; applying cricoid pressure to occlude the esophagus; administering pre-determined doses of rapid-onset sedative and neuromuscular-blocking drugs (traditionally thiopentone and suxamethonium) that induce prompt unconsciousness and paralysis; avoiding any artificial positive-pressure ventilation by mask after the patient stops breathing (to minimize insufflation of air into the stomach, which might otherwise provoke regurgitation); inserting a cuffed endotracheal tube with minimal delay; and then releasing the cricoid pressure after the cuff is inflated, with ventilation being started through the tube. There is no consensus around the precise definition of the term "modified RSI", but it is used to refer to various modifications that deviate from the classic sequence – usually to improve the patient's physiological stability during the procedure, at the expense of theoretically increasing the risk of regurgitation. Examples of such modifications include using various alternative drugs, omitting the cricoid pressure, or applying ventilation before the tube has been secured.

The procedure is used where general anesthesia must be induced before the patient has had time to fast long enough to empty the stomach; where the patient has a condition that makes aspiration more likely during induction of anesthesia, regardless of how long they have fasted (such as gastroesophageal reflux disease or advanced pregnancy); or where the patient has become unable to protect their own airway even before anesthesia (such as after a traumatic brain injury).

The induction drugs classically used for RSI have short durations of action, wearing off after only minutes. This confers a degree of fault tolerance on the procedure when it is used in elective or semi-elective settings: if intubation is unsuccessful, and if the clinical condition allows it, the procedure may be abandoned and the patient should regain the ability to protect their own airway sooner than would be the case under routine methods of induction. Conversely, in emergency settings where the patient's condition does not allow for them to be woken up immediately, a failed intubation under RSI places them at very high risk for respiratory compromise.