RSI Drugs Summary
Dr James French
- REDUCE THE DOSE OF INDUCTION AGENTS IN HYPOTENSION or when Pulse Rate is greater than Systolic Blood Pressure.
- INCREASE THE DOSE OF PARALYZING AGENTS IN HYPOTENSION.
Give the sedative first, followed by a flush, followed by the parlaying agent, followed by a small fluid bolus.
KETAMINE
Ketamine is a dissociating sedative that that can also be used in lower doses for procedural sedation ( i.v. 0.5 – 1.0mg/kg) and as a powerful analgesic (i.v. 0.3mg/Kg). When used for RSI the dose is 2.0 mg/Kg and is halved to 1.0 mg/kg in hypotension or a raised shock index (i.e. if the pulse is greater than the systolic blood pressure) . Ketamine causes hypertension, tachycardia and vomiting as its main side effects. When used for procedural sedation Ketamine causes less respiratory depression than other sedatives. Patients can misperceive stimuli during sedation and recovery and become agitated; this is called “emergence”.
Ketamine is available as 10mg/ml concentration for IV use and a 50 mg/ml concentration for IM use only – confusing the concentration being used can cause cardiac arrest. The 10mg/ml concentration is used neat for analgesia, sedation and RSI in adult patients.
ETOMIDATE
Etomidate is a sedative. It has no analgesic effect.
Etomidate’s chief side effect is hypotension, hypoventilation and adrenal suppression. When used for RSI iv the dose is 0.3. In hypotension or is the pulse rate us greater than the systolic blood pressure the dose of per Kg is halved from 0.3 to 0.15 mg/kg to prevent post induction hemodynamic instability.
Etomidate can cause a myoclonic jerk which are a single gross limb movements. It has a rapid onset of 45 seconds.
Etomidate is short acting – The sedation effect lasts about 5 minutes.
Etomidate is usually dispensed as a white liquid in a single 10ml ampoule, which has a concentration of 2mg/ml.
SUCCINYCHOLINE
Succinylcholine is a depolarizing muscle relaxant that acts on acetylcholine receptors. It works by binding non-competitively to the muscular acetylcholine receptor. This causes muscular relaxation by “burning out” the neuromuscular mechanism. This activation of the neuromuscular junction causes fasiculations.
Succinylcholine also acts on the acetylcholine receptors on the heart causing bradycardia as its primary side effect, particularly when giving a second dose. 5 mcg/kg of Atropine is therefor given before the second dose of Succinylcholine and in children under one year of age (who are more prone to bradycardia).
Succinylcholine works rapidly, with optimal relaxation in the jaw produced 10 seconds after fasciculations finish in the face.
The paralyzing effect wears off after about 6 – 9 minutes.
Succinylcholine provides no analgesic or sedative effect so it is essential that analgesia and sedation are given after anesthesia.
Succinylcholine is given neat. is a clear liquid and is supplied in one concentration of 20 mg/ml in a glass ampoule containing 100mg.
Succinylcholine dose in adults is 1.5 mg kg. The dose can be increased in severe shock to 2.0 mg/kg and in children. Do not “underdose” the paralyzing drugs so round up when doing drug calculations. Especially do not practice “ampoule based medicine” when using paralyzing agents in emergency situations.
Succinylcholine cannot be given to anybody with acute or chronic neuromuscular disease.
ROCURONIUM
Rocuronium is a non-depolarizing muscle relaxant. It does not activate the acetylcholine receptor but blocks the bodies own neurotransmitter. It therefore does not cause fasciculations.
Rocuronium also blocks the action of acetylcholine on the heart causing tachycardia as its primary side effect.
Rocuronium is fast onset proving intubating conditions in 60 seconds when given in the correct dose – it is essential that this period is timed after administration.
Rocuronium is long acting providing muscular parlays for about 45 minutes. It provides no analgesic or sedative effect so it is essential that analgesia and sedation are given after anesthesia.
Rocuronium is given as 1.5mg/kg, which is a dose increase, so does not need to be adjusted in severe hypotension.
Rocuronium is given neat and is supplied as a colourless liquid of 10 mg/ml concentration.
Lessons from Case Review and the Literature.
- REDUCE THE DOSE OF INDUCTION AGENTS IN HYPOTENSION.
- INCREASE THE DOSE OF PARALYZING AGENTS IN HYPOTENSION.
- Give the sedative first, followed by a flush, followed by the parlaying agent, followed by a small fluid bolus.
- Time from the moment the drugs are given to prevent the intubator from making the first attempt too early.
- When pushing the drugs make sure the IV line is blocked off to prevent the drugs from being pushed back into the giving set.
- Use IV access on the opposite side of the blood pressure cuff.
- Always follow RSI drugs with analgesia first after the tube is secured.
- Give the RSI drugs rapidly, fast IV push, sedative first, then the paralysing agent followed by a large flush or fluid bolus.
- Do not paralyze the hypoxic patient until every attempt to restore hypoxia has been corrected.
- Resuscitate the circulation with haemorrhage control and blood products, or fluid and vasopressors prior to RSI.
