When should PSA be used and avoided? What are the various levels of sedation? And what are some medications that can help you achieve and maintain sedation?
Hospital Procedures Consultants answers these questions and more in this article.
Common Hospital Procedures for Procedural Sedation (PS)
PS is used for many diagnostic and therapeutic procedures, including:
- Biopsy or incision and drainage (I&D) procedures
- Bone marrow biopsy and aspiration
- Chest tube placement
- Deep line placement
- Extensive burn debridement
- Fracture reductions
- Laceration repair
- Shoulder, elbow, or hip dislocations
- Synchronized direct current (DC) cardioversion
Foreign body removal CT or MRI scan sedation is also common.
Levels of Sedation
The European Journal of Anaesthesiology (EJA) defines five levels of sedation:
- Level 1: Fully awake
- Level 2: Drowsy
- Level 3: Anxiolysis. Asleep but rousable by normal speech.
- Level 4: Conscious/moderate sedation. Asleep but responding to standardized physical stimuli (e.g. glabellar tap).
- Level 5: Deep sedation. Asleep, but not responding to strong physical stimuli.
Level 5 is synonymous with general anesthesia.
For moderate-deep sedation, there is a higher risk of mortality. Hence, protocol dictates that clinicians must obtain informed consent; continuously monitor rhythm, SpO2, and ETCO2; have a separate certified provider for sedation; and be familiar with fasting guidelines for procedural sedation. The use of capnography can further improve patient safety by detecting hypoventilation episodes 17.6 times better than oximetry while reducing serious sedation-related complications.
Pre-Procedural Checklist
Who is a good candidate for procedural sedation? These factors will help you decide:
Indications for Procedural Sedation
Procedural sedation is indicated for patients with anxiety or pre-existing pain. It requires the patient to remain motionless for the duration of the painful procedure. To determine which patients require moderate and operating room sedation, ASA classification is used.
Contraindications for Procedural Sedation
Avoid procedural sedation if a patient refuses to give consent or has respiratory distress or hemodynamic instability. It’s also important to proceed with caution among elderly patients, patients under three months old, and patients with chronic lung, heart, liver, or renal disease.
Due Diligence for Procedural Sedation
All potent central nervous system (CNS) drugs can depress cardiac function. Typically, this is accompanied by a reduction in CO2 responsiveness. Combined, they can cause airway obstruction due to lower respiratory reserves, an impaired ability to generate protective arousal responses, and the loss of muscle tone.
Therefore, it is important to conduct an airway assessment to minimize the risk of impaired breathing, which is highest in patients with central obesity. Use the STOP-Bang Questionnaire for screening, followed by an airway examination which may include assessing neck extension and anatomical features. Meanwhile, the 3-3-2 rule can predict a difficult intubation.
Additionally, you should use the Mallampati score. Poor predictors of adverse events during procedural sedation are Mallampati III/IV, with a 30% rate of transient hypoxia. In children, a 2018 trial found a similar frequency of adverse events between Mallampati I/II vs Mallampati III/IV.
Use the Proper Medication
According to a case series, the most common medications used were fentanyl (94%), propofol (61.2%), midazolam (42.5%), and ketamine (2.7%).
Drugs can also be used to complement one another. Common sedative combinations include propofol and fentanyl as well as midazolam and fentanyl.
Opioids
Opioids provide analgesia and supplemental sedation during procedures requiring general anesthesia. Here are the common opioids used:
- Morphine: Bolus IV dosing of 2-4 mg, with a range of 2 mg IV q3 min. Its peak effect is 5-15 minutes, with a duration of action near 3–4 hours.
- Fentanyl: Bolus IV dosing of 0.5-1 mcg/kg (over 3-5 min), with a range of 0.25-0.5 mcg/kg IV q3 min. It has an immediate onset, with a duration of action near 30-60 minutes. It is typically 50-100x more potent than morphine.
- Hydromorphone: Bolus IV dosing of 0.5 – 1 mg IV (2 mg PO), and then 0.2 mg IV q3 min. It takes peak effect within 5 minutes, maintains effectiveness for 3-4 hours, and is 5 to 10 times more potent than morphine.
Since these are powerful drugs, their side effects must be considered when prescribing them to the older population and patients with impaired physical reserve. The dosage should also be tweaked for analgesia and sedation in children.
Ketamine
Ketamine causes analgesia and amnesia without cardiovascular and respiratory depression.
Consider contraindications before starting PS. Note that ketamine can have adverse side effects on procedural sedation, so stick to the right dosing—1-1.5 mg/kg (adults) or 1.5-2 mg/kg (children) IV, 4-5 mg/kg IM (children).
It can be paired with dexmedetomidine to help in the prevention of tachycardia, emergence phenomena, hypertension, salivation, bradycardia, and hypotension.
Etomidate
Etomidate at 0.1-0.15 mg/kg IVP provides effective, brief, deep sedation with little hemodynamic compromise and respiratory effects. However, apnea appears to occur in approximately 10% of patients. That said, etomidate/fentanyl is superior over propofol/fentanyl during cardioversion as it provides quick recovery and hemodynamic stability.
Propofol
Also called “milk of amnesia”, propofol is known for its fast onset and rapid systemic clearance.
It can be delivered via bolus IV dosing—1 mg/kg IV bolus then 0.5 mg/kg IV q3 min prn, or titration dosing—20 mg IV q 30-60 seconds. However, it has no analgesic properties, so it’s best to use it with fentanyl (0.5 mcg/kg) to alleviate pain. Per a 2019 study, using fentanyl 5 minutes before propofol will reduce the propofol dosage necessary and decrease the incidence of hypotension during induction.
Benzodiazepines
Midazolam is commonly used as it provides reliable anxiolysis, sedation, and amnesia. A review assessing its safety profile with propofol found that it didn’t lead to any deaths, and only one serious adverse event was recorded in the propofol group.
Bear in mind that each of these medications have their own contraindications and list of possible complications. Study them thoroughly before administering the sedatives.
Adverse Events of PSA in Adults
According to a systematic review, the most common adverse events are:
- Hypoxia, 40.2 per 1,000 sedations
- Vomiting, 16.4 per 1,000 sedations
- Hypotension, 15.2 per 1,000 sedations
Common adverse events in children are vomiting, agitation, hypoxia, and apnea.
Conclusion
The success of procedural sedation depends on careful and thorough patient assessment, the administration of drugs, and knowledge of potential adverse events. Hospital Procedures Consultants offers a Procedural Sedation Course that covers the necessary guidelines, indications, contraindications, drug dosages, and other relevant information healthcare practitioners must know about.
Resources
Corbett, G. Pugh, P. Herre, J. See, T. C. Monteverde-Robb, D. de Torres, R. T. Saunders, R. Leonard, C. Prakash, A. Service Evaluation of the Impact of Capnography on the Safety of Procedural Sedation. Front Med (Lausanne). 2022; 9: 867536. 2022 May 6. doi: 10.3389/fmed.2022.867536
Hinkelbein, J. Lamperti, M. Akeson, J. Santos, J. Costa, J. De Robertis, E. Longrois, D. Novak-Jankovic, V. Petrini, F. Struys, M. M. R. F. Veyckemans, F. Fuchs-Buder, T. Fitzgerald, R. (3)European Society of Anaesthesiology and European Board of Anaesthesiology guidelines for procedural sedation and analgesia in adults. Review Eur J Anaesthesiol. 2018 Jan;35(1):6-24. doi: 10.1097
Green, S. M. Leroy, P. L. Roback, M. G. Irwin, M. G. Andolfatto, G. Babl, F. E. Barbi, E. Costa, L. R. Absalom, A. Carlson, D. W. Krauss, B. S. Roelofse, J. Yuen, V. M. Alcaino, E. Costa, P. S. Mason, K. P. An international multidisciplinary consensus statement on fasting before procedural sedation in adults and children. Review Anaesthesia. 2020 Mar;75(3):374-385. doi: 10.1111/anae.14892. Epub 2019 Dec 2
Pansini, V. Curatola, A. Gatto, A. Lazzareschi, I. Ruggiero, A. Chiaretti, A. Intranasal drugs for analgesia and sedation in children admitted to pediatric emergency department: a narrative review. Review Ann Transl Med. 2021 Jan;9(2):189. doi: 10.21037/atm-20-5177.
Hinkelbein, J. Schmitz, J. Lamperti, M. Fuchs-Buder, T. Procedural sedation outside the operating room. Review Curr Opin Anaesthesiol. 2020 Aug;33(4):533-538. doi: 10.1097