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 patients 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. Common medications
Premedication
Premedication is used to reduce anxiety of those who are going to be intubated and to reduce the anticipated physiological response of the patient during intubation. Midazolam – It is a fast-acting and the most lipophilic of all benzodiazepine and rapidly crosses the blood–brain barrier.
Neostigmine – It can be used to reverse nondepolarizing neuromuscular blocking agents which cannot be reversed with sugammadex, although its onset is much slower. It works by competing with acetylcholine for the binding sites of acetylcholinesterase, which in turn prevents the breaking down of acetylcholine. The dosage is between 0.03 and 0.07 mg/kg. The side effect of this drug is bradycardia. Therefore, glycopyrrolate should be given together with neostigmine to prevent bradycardia. Other medications
Thiopental
Metaraminol or ephedrine, where hypotension may occur secondary to the sedating drugs. Phenylephrine – This drug is administered to those with hypotension post intubation as a result of lidocaine, midazolam, fentanyl, propofol, and ketamine. The dosages range from 50 to 200 μg in adults. It has quick onset and quick elimination. The common side effect is reflex bradycardia. Technique
Rapid sequence intubation refers to the pharmacologically induced sedation and neuromuscular paralysis prior to intubation of the trachea. The technique is a quicker form of the process normally used to induce general anesthesia. A useful framework for describing the technique of RSI is the "seven Ps". Preparation
The patient is assessed to predict the difficulty of intubation. Continuous physiological monitoring such as ECG and pulse oximetry is put on the patient. The equipment and drugs for the intubation are planned, including the endotracheal tube size, the laryngoscope size, and drug dosage. Drugs are prepared in syringes. Intravenous access is obtained to deliver the drugs, usually by placing one or two IV cannulae.