The dosage is 1 to 2 mg/kg, usually given at 100 mg. Ketamine is metabolised by liver and excreted through kidneys. The drug lessen the reuptake of the catecholamine, increases heart rate, blood pressure, and cardiac output, thus suitable for those with hypotension. However, it can worsen the cardiac depression and hypotension for those with depletion of catecholamines. Thus, maximum dose of 1.5 mg/kg is need for this situation. For those with head injuries, ketamine does not appear to increase intracranial pressure, while able to maintain the mean arterial pressure. Ketamine also relieves bronchospasm by relaxing bronchiolar smooth muscles. However, it increases oral secretions during intubation. Ketamine is associated with nightmares, delirium, and hallucinations. Propofol – It is a highly lipid-soluble, GABA agonist. The dosage is 1.5 mg/kg (usually 100 to 200 mg). It has quick onset of action, can cross the blood-brain barrier, wide tissue distribution, and can be cleared by the body quickly. In  the elderly, the rate of propofol clearance is low. Therefore, lower doses of propofol (50 to 100 mg) should be given. It is suitable in those with kidney or liver impairment and decreases intra-cranial pressure. For those with bronchospasm, propofol also has mild bronchodilating effect. However, propofol can induce hypotension and bradycardia due to its calcium channel blocker and beta blocker properties. At prolonged high propofol dosages, it can induce propofol infusion syndrome. Pain during peripheral administration of propofol can be reduced by using a large bore cannula.
Modern practice involves the passing of a ‘Bougie’, a thin tube, past the vocal cords and over which the endotracheal tube is then passed. The bougie is then removed and an inbuilt cuff at the end of the tube is inflated, (via a thin secondary tube and a syringe), to hold it in place and prevent aspiration of stomach contents. The position of the tube in the trachea can be confirmed in a number of ways, including observing increasing end tidal carbon dioxide, auscultation of both lungs and stomach, chest movement, and misting of the tube. Postintubation management
Malpositioning of the endotracheal tube (in a bronchus, above the glottis, or in the esophagus) should be excluded by confirmation of end tidal CO2, auscultation and observation of bilateral chest rise. One important difference between RSI and routine tracheal intubation is that the practitioner does not typically manually assist the ventilation of the lungs after the onset of general anesthesia and cessation of breathing, until the trachea has been intubated and the cuff has been inflated. Additional considerations
Age can play a role in whether or not the procedure is warranted, and is commonly needed in younger persons. The clinician that performs RSI must be skilled in tracheal intubation and also in bag valve mask ventilation. Alternative airway management devices must be immediately available, in the event the trachea cannot be intubated using conventional techniques. Such devices include the combitube and the laryngeal mask airway.