Procedural analgesia and sedation is not without complications where performed hastily and without proper understanding of medication pharmacology. It is best performed with two clinicians, one to manage the airway and one to administer the medication.
Aim: to induce a state of tolerance to emergency procedures while preserving airway reflexes; this is usually achieved by combining a sedative (or dissociative) with the analgesic.
Technique:
- appropriate personnel
- thorough patient assessment and consent:
- Past Medical History
- Anaesthetic History
- Medication and Allergies
- Recent food intake – not a contraindication, but used to determine depth of sedation
- adequate equipment:
- Oxygen via nasal cannula
- suction
- ALS equipment
- reversal agents
- intravenous cannula; preferably two access sites
- cardiac monitor
- pulse oximetry
- patient monitoring
- documentation
Only then consider administration of fentanyl alone or either midazolam or ketamine with fentanyl, depending on the procedure and patient:
Midazolam 0.05 mg/kg q 3-5 min (30-60 min duration of action)
- up to 1 – 2 mg in adults, with increments every 3-5 minutes
- 0.1 mg / kg will usually produce sedation within 2 – 3 minutes
- 1% of children will experience paradoxical excitation which can be reversed with flumazenil
Fentanyl 0.2-1 μg/kg 3-5 min. (20 – 30 minute duration)
- given slowly, and incrementally to a total dose of 2 – 3 μg / kg
- peak analgesia in 2 – 3 minutes
- contraindicated in < 6 months old because of risk of severe laryngospasm
- rigid chest syndrome appears to occur with rapid administration of a high dose (> 15 μg / kg)
Ketamine 0.5-1.0 mg/kg (45 minute duration of action)
Ketamine has the advantage of no hypotensive effect (may cause hypertension, tachycardia) and is the sedative of choice in asthma.
Other sedative/anaesthetic agents that are used instead of midazolam or ketamine:
- etomidate: 0.1 mg / kg (20 minute duration), rapid onset and recovery time and relative lack of significant hemodynamic effects
- propofol: 1.0 mg / kg (3-5 minute duration), good in asthma
The ideal agent varies with the clinical circumstance. “Ketofol,” or the combined use of ketamine (0.5 mg/kg) and propofol (0.5 mg/kg) given intravenously is a popular procedural sedation regimen, that can be followed, for a more prolonged procedure, by an intravenous propofol infusion run at 0.25 mg/kg intravenously (although a prolonged propofol infusion may leave the patient with an enduring sedation for some time).
Safe administration involves slow titration until the desired effect is achieved. Consideration at all times must be given to the need for, and appropriate administration of, any reversal agent. For severe respiratory depression, give:
Naloxone 0.1 mg/kg (1-2 mg dose in adults) IVI
- for severe respiratory depression
- onset rapid but duration relatively short (20-40 minutes)
- re-sedation may occur if longer-acting opioids were used
- can often circumvent this by giving half dose intravenously and half the dose intramuscularly
- children: 5 micrograms/kg/dose given intravenously over 1 – 2 minutes; can be repeated every 2 – 3
minutes. Maximum cumulative dose 2 mg
Flumazenil 0.02 mg/kg: or 0.2 mg over 15 seconds in adult
- can repeat at 1-minute intervals until desired effect
- duration of action 20-40 minutes
- risk re-sedation and seizures, especially in chronic benzodiazepine users
- children: 5 micrograms/kg/dose given intravenously over 15 seconds for benzodiazepine-induced over-sedation; can be repeated every 1 – 2 minutes (max single dose 200 mcg; max cumulative dose 40 mcg/kg or 2 mg)
General or post-procedure analgesia:
- avoid NSAIDs in patients with healing fractures as NSAIDs can decrease bone formation and healing
- use NSAIDs for blunt muscle trauma, various sprains and strains, as they stimulate collagen synthesis in early phases of skin and ligament repair
- of the opioids, avoid codeine, especially in children, as it has an unpredictable efficacy courtesy of erratic pharmacokinetics
- avoid opioids in pregnant or lactating women
- be judicious when dispensing opioids as any take-home medication;
The aim of procedural analgesia is to induce a state of tolerance to the procedure and, combined with the anamnestic effect of a benzodiazepine, this should suffice; equally, while no patient should suffer neither does the patient need to be narcotised into a blissful state of indifference; the patient that is discharged should be able to have a reasonably comfortable night’s sleep, rather than necessarily remove every last sensation of pain.
Further:
- Procedural Sedation – Medications | Emergency Care Institute (nsw.gov.au)
- Procedural Sedation In The Emergency Department – SCH
