Procedural Sedation in the ED

There are no absolute indications for procedural (conscious) sedation, but it can be very helpful to facilitate imaging studies or invasive procedures. In particular, procedural sedation can be useful for painful and anxiety-producing procedures like laceration repairs and joint reductions, especially in children.

The term “procedural sedation” is roughly equivalent to moderate sedation, which means that the patient has a depressed consciousness but can still protect their airway and respond to some commands or questions. During a procedural sedation, an ED provider is always in verbal contact with the patient.

Before administering sedating medications, it’s important to have all the right equipment. You can use the mnemonic SOAPME to remember the most important things:

S: suction

O: oxygen

A: airway equipment – non-rebreather, nasal cannula, BVM, LMA, ET tubes

P: pharmacy – any medications to treat the sedative’s adverse effects or antidotes like flumazenil and naloxone

M: monitoring – a blood pressure monitor, pulse oximetry, end-tidal CO2 monitor

E: equipment – anything else you might need, including defibrillator, etc.

When you’re ready to start, make sure to document a set of vital signs before you give any medication, and keep the patient attached to the monitor. You want the patient to be placed on the ET-CO2 monitor so that you can ensure adequate ventilation. A normal capnogram looks like this (1): 

The plateau phase of your end-tidal CO2 monitor should be around 35-45 mm Hg. Capnography can also be useful for detecting laryngospasm or apnea, which would both show flat or undetectable readings on the monitor along with desaturations.

You should take a look at the oropharynx to judge the potential difficulty of any emergent airway procedures. And don’t worry if the patient hasn’t been NPO: the theoretical risk of aspiration hasn’t been proven in the literature. The Pediatric Sedation Research Consortium (PSRC) published data in 2016 showing no significant difference in aspiration events or major complications based on NPO status (2). The ACEP clinical policy recommends (level B) that procedural sedation should not be delayed in the ED based on fasting time (3).

The next step is to choose your medication. There are a few commonly used options, including:

Ketamine

Benefits: minimal effect on blood pressure, maintenance of respiratory drive; effects include analgesia, sedation, and amnesia

Dose: 1 mg/kg IV or 2-5 mg/kg IM

Duration: IV – about 10 minutes; IM – about 40 minutes 

Side Effects: Watch out for laryngospasm, particularly in children. If you observe laryngospasm, ventilate the patient with BVM and wait for the medication to wear off. You should also be aware of vomiting and emergence reactions as potential side effects. If you observe an emergence reaction, you can treat with midazolam or other benzodiazepines. Ketamine can also cause hypersalivation and increased intraocular pressure, both of which are not usually clinically important.

Midazolam

Benefits: short-acting; can be combined with an opioid (fentanyl); reversal agent available; generally minimal sedation when used alone

Dose: 0.05-0.1 mg/kg IV or 0.1 mg/kg IM. Can also be given PO, PR, or intranasal, although these are not often used due to variable onset/duration.

Duration: IV – about 20-30 minutes

Side Effects: Be aware of the possibility of respiratory depression, as well as paradoxical agitation due to the disinhibitory effect of benzodiazepines.

Propofol

Benefits: short duration; subsequent doses can have greater effects

Dose: 0.5-1 mg/kg, then 0.5 mg/kg as needed every 3 minutes

Duration: 5-6 minutes

Side Effects: Watch out for hypotension, respiratory depression and pain or burning at the infusion site.

Fentanyl

Benefits: rapid onset; can be combined with a benzodiazepine (midazolam); generally minimal sedation when used alone

Dose: 1-3 mcg/kg IV, can give up to 5 mcg/kg

Duration: 30-60 minutes

Side Effects: Beware of rigid chest syndrome (4,5), which occurs more commonly with higher doses or with rapid IV boluses/rapid flushing of IV line. You should push fentanyl slowly and flush the line slowly, especially in children!

Different agents can be combined (fentanyl + midazolam, ketamine + propofol = ketofol) for synergistic effects or to ensure sedation and analgesia. Ketamine can help counteract the drop in blood pressure you may see when using propofol, which is particularly useful in patients with less reserve, such as elderly patients. Using ketofol can lower the total dose of either agent – typically we use a half-dose of each – though studies of its efficacy compared to either agent alone are mixed. For example, a 2011 rRCT compared ketofol to standard ketamine for procedural sedation. Their primary outcome was duration of sedation, but they also reported on adverse effects and patient satisfaction. The authors found statistically significant decreases in sedation time (13 minutes vs 16 minutes) and vomiting when using ketofol (6). Altogether, the clinical significance of these results is probably small. 

The 2016 POKER study compared ketofol to standard propofol for procedural sedation in the ED. The authors found more adverse respiratory events (desaturations, hypoventilation, or apnea) in the propofol group, though this was not statistically significant. Patients in the propofol group were significantly more likely to become transiently hypotensive (7).

But let’s get back to your patient…

You choose ketamine as your agent. You slowly push 1 mg/kg IV until you observe nystagmus, and the child says “I feel weird.”

You suture the laceration while your co-resident watches the child’s monitor, and a good capnogram tells you he is ventilating well. After completing the repair about 20 minutes later, the child starts moving and talking more, and his parents give him a big hug, and you a huge smile. “Nice job, doc.”

1. Duckworth RL. 2017. How to Read and Interpret End-Tidal Capnography Waveforms. Journal of Emergency Medical Services. Online. 

2. Beach ML et al. Major Adverse Events and Relationship to Nil per Os Status in Pediatric Sedation/Anesthesia Outside the Operating Room: A Report of the Pediatric Sedation Research Consortium. Anesthesiology. 124(1): 80-8. 2016

3. Godwin SA et al. Clinical policy: procedural sedation and analgesia in the emergency department. Ann Emerg Med. 2014; 63(2): 247-58

4. Coruh B et al. Fentanyl-Induced Chest Wall Rigidity. Chest. 143(4): 1145-1146. 2013.

5. Phua CK et al. Fentanyl-Induced Chest Wall Rigidity Syndrome in a Routine Bronchoscopy. Respiratory Medicine Case Reports. 20: 205-7. 2017.

6. Shah et al. A Blinded, Randomized Controlled Trial to Evaluate Ketamine/Propofol versus Ketamine Alone for Procedural Sedation in Children. Ann Emerg Med. 2011; 57(5): 425-33.

7. Ferguson et al. Propofol or Ketofol for Procedural Sedation and Analgesia in Emergency Medicine – the POKER Study: A Randomized Double-Blind Clinical Trial. Ann Emerg Med. 2016; 68(5): 574-582.

8. Cravero JP, Roback MG. Procedural Sedation in Children Outside of the Operating Room. UpToDate. Online. 2019.

9. Green SM, et al. 2015. Ketofol for Procedural Sedation Revisited: Pro and Con. Ann Emerg Med. vol. 65 (5): 489-491.

10. Sury M. Conscious Sedation in Children. Continuing Education in Anaesthesia Critical Care & Pain. 2012; 12(3): 152-156. 

11. http://www.tamingthesru.com/procedural-sedation

12. Weaver C. Procedural Sedation. In: Tintinalli JE. Tintinalli’s Emergency Medicine. 8th ed. New York: McGraw-Hill Medical; 2016: 249-255.