In this episode, I’ll discuss an article about propofol and moderate vs deep sedation.
Article
Lead author: Alexandra Schick
Published in Academic Emergency Medicine August 2018
Background
Propofol is frequently used in hospital emergency departments to provide a level of sedation that facilitates procedures such as orthopedic manipulation or foreign body removal near the eye. The authors of this study sought to determine if there was a difference in procedural amnesia and adverse respiratory events between the levels of moderate and deep sedation when using propofol.
Methods
The study was a prospective, randomized clinical trial of adult patients planning to undergo deep procedural sedation with propofol. Patients were randomized to a target sedation level of moderate or deep sedation. Drug doses, vital signs, observer’s assessment of alertness/sedation score, end tidal CO2 (ETCO2), and the need for supportive airway maneuvers (bag valve mask use, repositioning, and stimulation to induce respirations) were monitored continuously. Subclinical respiratory depression was defined as SaO2 ≤ 91%, change in ETCO2 ≥ 10 mm Hg, or the absence of ETCO2 at any time. The occurrence of respiratory depression with a supportive airway maneuver was defined as an adverse respiratory event.
Results
Approximately 100 patients were enrolled and split evenly between the moderate and deep sedation groups. Of the patients randomized to target moderate sedation, 50% achieved moderate and 50% achieved deep. In the target deep sedation group, 77% achieved deep and 23% achieved moderate. The median total propofol dose (mg/kg) was lower in the moderate sedation group: 1.4 vs 1.8 mg/kg.
There were no differences in assessments of sedation, alertness, or amnesia. In the moderate sedation group, 41% patients had at least 1 adverse respiratory event compared to 42% in the deep sedation group. The total number of adverse respiratory events was 23% lower in the moderate sedation group, and this was statistically significant (p=0.01). There was no difference in patient reported pain, satisfaction, or recollection scores. The provider’s rating of procedural difficulty and procedural success were similar in both groups.
Conclusion
The authors concluded:
Targeting moderate or deep sedation did not reliably result in the intended sedation level. Targeting moderate sedation, however, resulted in a lower rate of total AREs and fewer patients had multiple AREs with no difference in procedural recall. As seen in previous reports, patients who achieved moderate sedation had less AREs than those who achieved deep sedation. Our study suggests that a target of moderate sedation provides adequate amnesia with less need for supportive airway interventions than a target level of deep sedation, despite the fact that it often does not result in intended sedation level.
Discussion
The American Society of Anesthesiologists describes sedation as a continuum from minimal sedation to moderate sedation, deep sedation, and general anesthesia.
In a state of moderate sedation, no airway intervention should be required, spontaneous ventilation is adequate, and cardiovascular function is usually maintained.
In a state of deep sedation, intervention to maintain a patent airway may be required, spontaneous ventilation may be inadequate, and cardiovascular function is usually maintained.
The extremely high percentage of patients in this study – 50% – in which moderate sedation was intended but deep sedation was achieved instead is concerning from a safety standpoint. I am of the opinion that the intended depth of sedation during procedural sedation is in part related to the known potential side effects of the medications used.
Because propofol has the potential to depress the respiratory and cardiovascular systems at doses used to provide sedation, I consider it impossible to use propofol for moderate sedation. The results of this study support the idea that whenever propofol is used for procedural sedation, healthcare providers should be prepared for a level of deep sedation to be achieved, regardless of whether the intended level of sedation is moderate or deep.
Members of my Hospital Pharmacy Academy have access to my Masterclass training video on deep sedation where I provide an in-depth review of the indications, safety, and medication considerations from a pharmacist’s point of view for deep sedation procedures. To access this and over 50 other training videos go to pharmacyjoe.com/academy.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.
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