Procedural (Conscious) Sedation

Thomas C. Arnold, MD and Sean Denham, MD
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Introduction

In the practice of medicine today, allowing a patient to experience unnecessary pain is unacceptable. In fact, the Joint Commission’s recent attention to this issue has promoted the concept of pain as the “fifth vital sign” as we attempt to quantify and manage pain more aggressively. In no place is the anticipation of pain more acutely experienced by patients than in the application of many routine office-based, urgent care, or emergency department procedures that health-care providers are expected to provide on a daily basis. Although local and regional analgesia are very effective in a number of situations, there are many scenarios in which these techniques are not adequate, as a greater degree of analgesia and control are necessary to assure optimum results. 
“Conscious” sedation is a misnomer commonly applied to this procedure. It is imprecise because the patient really is not conscious if the sedation is performed properly. The anesthesia term for the actual sedation level is deep sedation. In the acute care setting, procedural sedation is now the accepted terminology and more accurately describes what we are performing. The implication is that the depth and length of the sedation will be specific and tailored to the procedure to be performed. 
The skill of applying procedural sedation safely and effectively requires practice and vigilance. The prudent practitioner will always focus on the patient during the sedation process while someone else attends to the procedure for which the sedation was required. Modern physiologic monitors have tremendously improved the safety of procedural sedation and should always be utilized to the extent available. Although blood pressure, heart rate, and pulse oximetry monitors are important, these physiologic parameters change late in the course of an apneic episode and may give the practitioner a false sense of security until emergent intervention is required. Conversely, monitors of respiratory effort such as capnography (end tidal CO2 detection) have proven useful in detecting depressed respiratory effort and apnea quickly and allow intervention or adjustments to be made earlier in the process. These adjuncts are valuable safety enhancements and are slowly becoming standard practice for all procedural sedations. 
Procedural sedation should be considered a complete procedure separate from the procedure for which the sedation is required. Informed consent with a clear explanation of risks and alternative options should be documented. It is helpful to have a procedural sedation packet containing all the required forms for consent, monitoring of induction, maintenance and recovery periods, and a checklist of equipment. Choice of agent(s) should be individualized to the needs of the patient and the experience and comfort of the practitioner. Procedural sedation has been performed safely by a large variety of practitioners in many practice settings and should become a routine tool for a variety of indications. 
The modern practitioner has a myriad of choices concerning the agents for procedural sedation. To give a complete listing of all available agents would be beyond the scope of this text; therefore, we focus on three different drugs or drug combinations: an opiate and benzodiazepine combination (fentanyl [Actig]/midazolam [versed]), a sedative/hypnotic (propofol [Diprivan]), and a dissociative agent (ketamine). 
Fentanyl is a very common opioid used for procedural sedation. Its popularity can be attributed to several factors including its rapid onset, brief duration of action, rapid reversibility by naloxone (Narcan), and lack of histamine release. Fentanyl is approximately 100 times more potent than morphine and has no intrinsic anxiolytic or amnestic properties. The effects of fentanyl can be rapidly and completely reversed with opioid antagonists (naloxone). Because anxiolysis and sedation do not occur at low doses of fentanyl (1 to 2 mcg/kg), the concurrent administration of a benzodiazepine, commonly midazolam is recommended. The combination of fentanyl and midazolam remains one of the most popular procedural sedation regimens in children, with a strong safety and efficacy profile when both drugs are carefully titrated to effect. Any necessary level of mild to deep sedation can be achieved using these agents. 
Ketamine is a dissociative agent that provides sedation, analgesia, and amnesia. It has been demonstrated to be a safe and effective anesthetic dissociative in a variety of settings. It has been widely used worldwide since its introduction in 1970 and has demonstrated a remarkable safety profile in a variety of settings. Ketamine differs from all other procedural sedation agents in several important ways. First, it uniquely preserves cardiopulmonary stability. Upper-airway muscular tone and protective airway reflexes are maintained. Spontaneous respiration is preserved, although when administered intravenously (IV), ketamine must be given slowly (over 1 to 2 minutes) to prevent respiratory depression. Second, it differs from other agents in that it lacks the characteristic dose-response continuum to progressive titration. However, practitioners administering ketamine must be especially knowledgeable about the unique actions of this drug and the numerous contraindications to its use. 
Propofol is a sedative-hypnotic agent that is unrelated to barbiturates or benzodiazepines. Given by IV bolus or by using an infusion pump, this drug can induce deep sedation or general anesthesia within 1 minute. Recovery following discontinuation averages 5 to 15 minutes, even after prolonged administration. Propofol exhibits inherent antiemetic and perhaps euphoric properties, and patient satisfaction is typically high. The adverse effects of this drug are potent respiratory and cardiovascular depression. However, recent studies continue to add to propofol’s already growing body of evidence of its strong safety profile. Propofol has become quite popular with practitioners who frequently perform procedural sedation, primarily because of the rapid patient recovery when this agent is used. 

Equipment

Noninvasive monitoring equipment to monitor oxygenation (pulse oximetry), hemodynamics (blood pressure), and ventilation (capnography) should be utilized during the sedation procedure to the extent available. 
  • Airway management devices:

    • Oxygen source

    • Bag-valve mask

    • Equipment for rapid sequence intubation (see Endotracheal Intubation)

    • Suction apparatus

  • Agent(s) for sedation

Indications

  • Foreign-body removal: ears of children, rectum of adults

  • Incision and drainage of an abscess: if local anesthesia is inadequate

  • Imaging in children

  • Complicated laceration repair in children

  • Simple reduction of dislocated joints

  • Closed reduction of fractures

  • Reduction of fracture dislocations

  • Wound management: debridement, significant pain, large surface area, severe burns

Contraindications

  • Patient refusal in a competent individual

  • Severe clinical instability requiring immediate attention

  • Hemodynamic or respiratory compromise

  • Altered sensorium or inability to monitor side effects

Although safely sedating patients at the extremes of age is challenging and requires additional care, age is not a contraindication to procedural sedation. 

The Procedure

Step 1

Preparation. Written informed consent should be obtained and documented in the patient record (see Appendix A). Obtain intravenous access. Assemble appropriate patient monitoring devices including heart rhythm (electrocardiographic), blood pressure, oximetry, and backup airway management devices such as a bag-valve mask and oral airways and intubating equipment. 
  • PEARL: Peripheral access is usually sufficient with a catheter size large enough to provide resuscitation fluids if necessary.

  • PEARL: Recent studies have shown support for preoxygenation and capnography, which may add to the safety of procedural sedation by detecting hypoventilation earlier than clinical assessment and pulse oximetry alone.

Step 2

Administer sedation agents while monitoring the patient. Recommended doses are shown in Table 4-1. Administration of the sedating agents should proceed slowly with gradual titration to the desired depth depending on the procedure being performed and length of time sedation will be necessary. The practitioner administering the procedural sedation should maintain vigilant observation of respiratory effort, airway patency, and vital signs while not becoming distracted by the procedure being performed. 
  • PEARL: Titrate the procedural sedation to the point that the patient’s pain is relieved. This point will vary between procedures and during different parts of procedures.

  • PITFALL: The most common clinical errors are delayed recognition of respiratory depression and respiratory arrest, inadequate monitoring, and inadequate resuscitation.

 
Table 4-1.
Drugs Used and Doses for Procedural Sedation and Analgesia

Step 3

The postprocedure management phase is critical and includes close observation of all monitoring parameters until the patient is fully conscious. 

Complications

  • Delayed awakening.

  • Agitation.

  • Nausea and vomiting.

  • Cardiorespiratory events.

  • Tachycardia.

  • Bradycardia.

  • Hypoxia.

  • Respiratory depression: Like all opioids, fentanyl can cause respiratory depression. When respiratory depression occurs with fentanyl/midazolam procedural sedation, usually it is due primarily to fentanyl. As the opioid effect is most pronounced on the central nervous system respiratory centers, apnea can precede loss of consciousness. Caution must be exercised when using benzodiazepines and opioids together, because the risks of hypoxia and apnea are significantly greater than when either is used alone.

  • Hallucinatory “emergence reactions”: These have been reported in up to 30% of adults receiving ketamine (although rare in children) and can be fascinating and pleasurable or alternatively unpleasant and nightmarish. Concurrent benzodiazepines are believed to blunt but not entirely eliminate such reactions in adults, and apprehension regarding such unpleasant recoveries has limited the popularity of ketamine.

Pediatric Considerations

See pediatric doses in Table 4-1. Because children cannot reliably judge how impaired they are after the procedure, they should be monitored closely for 2 hours after the procedure by responsible adults. 

Postprocedure Instructions

All patients receiving procedural sedation should be monitored until they are no longer at risk for cardiorespiratory depression. To be discharged, they should be alert and oriented (or returned to age-appropriate baseline), and vital signs should be stable. All patients should leave the hospital with a reliable adult who will observe them after discharge for postprocedure complications. It is desirable to document the name of the individual on the hospital record. Even though patients may appear awake and able to comprehend instructions, they may not remember details once they leave the facility. 

Coding Information and Supply Sources

  • Physiologic monitors and laryngoscope devices can be ordered directly from Welch Allyn at http://www.welchallyn.com/ or through their corporate headquarters at 4341 State Street Road, Skaneateles Falls, New York, 13153-0220. Phone: 1-800-535-6663.

  • Other airway supplies can be ordered from Mallinckrodt at http://www.mallinckrodt.com/ or their corporate headquarters, 675 McDonnell Blvd. Hazelwood, MO 63042. Phone: 314-654-2000.

Bibliography

Cote CJ, Karl HW, Notterman DA, et al. Adverse sedation events in pediatrics: a critical incident analysis of contributing factors. Pediatrics 2000;105:805. [View Abstract]
Chudnofsky CR, Wright SW, Dronen SC, et al. The safety of fentanyl use in the emergency department. Ann Emerg Med. 1989;18:635. [View Abstract]
Gottschling S, Meyer S, Reinhard H, Furtwangler R, Klotz D, Graf N. Intraindividual propofol dosage variability in children undergoing repetitive procedural sedations. Pediatr Hematol Oncol. 2006;23(7):571–578. [View Abstract]
Green SM, Clem KJ, Rothrock SG. Ketamine safety profile in the developing world—survey of practitioners. Acad Emerg Med. 1996;3:598. [View Abstract]
Mensour M, Pineau R, Sahai V, et al. Emergency department procedural sedation and analgesia: a Canadian Community Effectiveness and Safety Study (ACCESS). Can J Emerg Med Care 2006;8(2):94–99. [View Abstract]
Pena BMG, Krauss B. Adverse events of procedural sedation and analgesia in a pediatric emergency department. Ann Emerg Med.  1999;34:483. [View Abstract]
Sacchetti A, Senula G, Strickland J, et al. Procedural sedation in the community emergency department: initial results of the ProSCED registry. Acad Emerg Med. 2006;14(1):41–46. [View Abstract]
2008 MAG Mutual Healthcare Solutions, Inc.’sPhysicians’ Fee and Coding Guide. Duluth, Georgia. MAG Mutual Healthcare Solutions, Inc.2007.
 
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