Quote from MedicRN111
I always get a laugh when people who dont order the meds nor have any clue on how they work, start to offer their advice. Here is correct and recommended doses for RSI, from someone who does it every day.
Even funnier when someone makes a statement like this, then promptly makes a number of mistakes in their recipie.
From an anesthesia perspective, there are a lot of ways to skin the cat. I have used each of the drugs listed in various RSI scenarios, depending on the variables that different patients will have, and none of the drugs are "wrong" per se. Since doses are available everywhere, just a few comments about the drugs.
Lidocaine: Given for two reasons. First, if using propofol, it may attenuate the burning vein sensation that can accompany this drug's administration. Second, given IV, it can help to anesthetize the airway, making the patient less likely to buck against the tube once the paralytic wears off. 300 mg of lidocaine is a HUGE dose, and can cause the patient to seize. It won't help with fasciculations anyway. Back off on that dose.
Fentanyl: 3 mg/kg? Wow. Never given that much to a patient in my life. It is a narcotic, and can be given to a patient either in pain or about to undergo a painful procedure. When called to the ER for RSI, I don't take fentanyl along. I don't need it.
Versed: Given IV, it has rapid onset, causing sedation and amnesia. USUALLY, it has little or no effect on respiratory effort. Often, when called to the ICU to intubate a patient, it is the only drug I give prior to intubation. I dose it to effect, then proceed with direct laryngoscopy. However, if doing an RSI fearing potential aspiration, I'll usually give one of the hypnotics and sux.
Etomidate: Not my favorite drug for induction of general anesthesia, but it does have a place. Propofol is faster acting, but if the patient has a significant cardiac history, I'll use etomidate. If they have a potential brain injury, I'll use sodium thiopental. And as I already said, often I don't give this class of drug at all for emergent intubations outside of the OR.
Succinylcholine: A rapid and short acting depolarizing paralytic. Give atropine with it when giving the drug to peds patients, as sux can cause profound bradycardia in kids. Also, it is a depolarizer, and will cause a rise in K+ levels, so don't give it to someone who already has a high potassium level. Fasciculations are the muscle twitches you see when the drug causes depolarization, resulting in tensing of the skeletal muscle. This can leave the patient with mild to moderate myalgia for a day or so after administration. Once you understand the drug, you understand that giving 10% of the calculated dose to prevent fasciculations (called a defasciculating dose) is a waste of time. Your initial dose will simply cause milder fasciculations that you may not be able to observe, but can still leave the patient with the myalgia you are trying to prevent.
There is an upside to fasciculation. Fasciculation can be a direct monitor to tell you exactly when a patient is ready for intubation. Give the sux, then watch the patient's eyelids. In a moment, the eyelid will flutter. When the fluttering stops, intubate the patient. Since you cannot bag ventilate a patient who needs an RSI, and we have all seen patients who, even after prolonged prebreathing of 100% O2, desaturate quickly, sometimes it is in the patient's best interest to trade a short time of mild muscle pain for a direct, easily observed monitor of when you can tube the patient. (By the way, this is not recommended for potential head injury patients, as the fasciculations caused can cause a transient increase in ICP. However, there has been some discussion in the literature lately suggesting that this transient increase may not be clinically significant.)
Non-depolarizing neuromuscular blockers: (i.e. vecuronium, etc) These are much longer acting paralytics, and take longer to take effect than sux. The only one considered acceptable for RSI is rocuronium, and if you are going to use it, you better be damn sure you will be able to intubate the patient. In small doses, i.e. 5 - 10% of a calculated intubation dose, these are the only drugs that will prevent the fasciculations caused by succinylcholine. Once the sux has worn off, these drugs may be given to provide longer paralysis to prevent patient movement.
RSI is done whenever you are intubating a patient with a known or potential full stomach (i.e. they have eaten in the last 8 hours) or someone with known GERD. To my way of thinking, this means all ER intubations are RSI. If you are doing an RSI, you also must also have someone doing cricoid pressure. Pressure is applied at the cricoid membrane, NOT THE thyroid cartilage. The textbook says you must apply about 44 Newtons of pressure. That's about 10 pounds. Do not release the pressure until tube position is confirmed by CO2 and ascultation of breath sounds. It is done to help prevent vomiting and aspiration.