Procedu ral Sedation

Pa ula E. Oldeg, MD

Key Points

• Procedural sedation is the admin istration of analgesic

and sedative agents to induce a depressed level of

consciousness so that a medical procedure can be performed without patient movement or memory.

INDICATIONS

Procedural sedation is a clinical technique that creates a

decreased level of awareness, but allows maintenance of

protective airway reflexes and adequate spontaneous ventilation. The goals of procedural sedation are to provide

analgesia, amnesia, and anxiolysis during a potentially

painful or frightening procedure. Pharmacologic agents

used in procedural sedation are of 3 general classes: seda ­

tives, analgesics, and dissociative agents. The use of such

medications in the emergency setting is common and has

been shown to be safe. Before the procedure, the physician

should assess the patient for systemic disease and for a

potential difficult airway. The patient's fitness for sedation

can be quantified using the American Society of

Anesthesiologists (ASA) physical status classification sys ­

tem (Table 4-1). The risk of a complication from emer ­

gency department (ED) procedural sedation and analgesia

in ASA class I and II patients is low, usually <So/o.

Examples of clinical scenarios appropriate for procedural

sedation include painful or anxiety-provoking situations s uch

as joint or fracture reduction, lumbar puncture, pediatric

radiologic studies, incision and drainage, or cardioversion.

CONTRAINDICATIONS

Contraindications include ASA class III/IV, altered mental

status, hemodynamic instability, known medication

allergy, and lack of equipment or qualified personnel. Oral

13

• Procedural sedation should maintain cardiorespiratory

function without requiring advanced airway adjuncts.

• Preprocedure patient assessment and proper selection

of pharmacologic agents are the keys to patient safety.

Table 4-1. The American Society of Anesthesiologists

physical status classification.

I. Healthy patient

II. Mild systemic disease-no functional limitation

111. Severe system disease-definite functional limitation

IV. Severe systemic disease-constant threat to life

v. Moribund patient-not expected to survive without the

operation

Data from American Society of Anesthesiologists. ASA Physical Status

Classification System. http:/ jwww.asahq.org

intake within 3 hours is a relative contraindication. Higher

risk cases may be more safely performed with anesthesia

consultation or in the operating room.

EQUIPMENT

Patients should be closely monitored to recognize any

change in vital signs and avert complications, most notably

respiratory depression. Continuous pulse oximetry, cardiac

monitor, and end-tidal C02 capnography (if available)

should be applied. Intravenous (IV) access, an oxygen

source and delivery method (eg, nasal canula), suction,

airway management equipment (ie, bag-valve-mask,

supraglottic airway, laryngoscope, endotracheal tube),

CHAPTER 4

resuscitation cart, and reversal drugs should be readily

available. Personnel should be skilled in airway management and patient monitoring and recovery.

PROCEDURE

Appropriate preprocedure history includes allergies to or

adverse effects from anesthetic agents, medical conditions,

and time of last oral intake. Physical exam should include

a thorough airway assessment to predict difficulty with

bag-valve-mask ventilation or endotracheal intubation.

Consider the presence of dentures, neck mobility, obesity,

and Mallampati scale (Figure 4-1). Sedation in the emer ­

gency department should generally be limited to ASA class

I and II patients. A fasting period of 3 hours is recommended; however, studies have shown that a shorter period

does not increase the incidence of aspiration. The urgency

of the procedure often dictates acceptable preprocedure

fasting period. Obtain informed consent and document

the conversation in the record. Many institutions have a

standardized procedural sedation record for recording

consent as well as pertinent history and physical.

Appropriate personnel to perform the procedure,

administer medications, and monitor the patient should

assemble at the bedside. The medications are administered

and titrated to effect. Medication selection is guided by the

type of procedure being performed (Table 4-2). Using a

combination of a sedative/analgesic (eg, midazolam/

fentanyl) generally gives consistent clinical results. Other

commonly used regimens include ketamine alone or with

atropine (0.0 1 mg/kg IV or IM) for pediatric cases,

propofol plus an analgesic (fentanyl), or midazolam plus an

analgesic.

The physician should perform the procedure as a nurse

or other physician monitors the patient. After completion

of the procedure, the patient should be monitored until

mental status returns to baseline. Discharge criteria

include stable vital signs, return to baseline mental status,

Class I Class II

Class Ill Class IV

Figure 4-1. Mallampati classification. (Reprinted with

permission from Vissers RJ. Chapter 30. Tracheal

Intubation and Mechanical Ventilation. In: Tintinalli JE,

Stapczynski JS, Cline DM, Ma OJ, Cydulka RK, Meckler GD,

eds. Tintinalli's Emergency Medicine: A Comprehensive

Study Guide. 7th ed. New York: McGraw-Hill, 201 1 .)

Table 4-2. Common med ications used for procedural sedation in the ED.

Drug (Class) Dose Effects Onset Duration Side Effects Reversal Agent

Midazolam 0.02-o.1 mgjkg IV Sedation, amnesia, 2 min 20-30 min Apnea, hypotension Flu maze nil

(benzodiazepine) anxiolysis

Morphine ( opioid) 0.1-o.2 mgjkg IV Analgesia 2 min 3-4 hr Histamine release Naloxone

Fentanyl (opioid) 0.5-1 meg/kg to total Analgesia, mild 2 min 30 min Respiratory depression and Naloxone

dose of 2-3 meg/kg IV sedation rigid chest syndrome

Ketamine 0.5-1 mgjkg IV or Sedation, amnesia, 1 min 1-2 hr Secretions, tachycardia, None

(PCP derivative) 3-5 mgjkg IM analgesia, emergence reactions,

anxiolysis increased intracranial pressure

Etomidate (imidazole 0.1-o.2 mgjkg IV Sedation, amnesia, 30 sec 1 0-30 min Myoclonus, apnea None

derivative) anxiolysis

Propofol (phenol 1-2 mgjkg IV Sedation, amnesia 40 sec 3-5 min Hypotension, bradycardia, None

compound) injection site pain

PROCEDURAL SEDATION

Table 4-3. Reversal agents.

Drug Dose Effect Onset Duration Side effects

Flumazenil 0.2 mg IV may be repeated to benzodiazepine antagonist 1-2 min 45 min Seizures, symptoms of benzo withdrawal

max 1 mg

Naloxone 0.1-2 mg IV opioid antagonist

ability to tolerate liquids, and an understanding of discharge instructions.

COMPLICATIONS

Respiratory depression is the most common adverse

reaction. Close observation of the patient's pulse oximetry

and respiratory effort can alert the physician to potential

airway compromise. Support respirations by positioning

the airway and providing bag-valve-mask ventilations if

needed. Recent data have supported the use of continuous

end-tidal C02 monitoring to recognize hypoventilation

before hypoxia is seen on pulse oximetry. If respiratory

depression persists, consider administration of a reversal

agent (Table 4-3). Nausea and vomiting is another possible

side effect. Prevent aspiration and ensure the airway is clear

by turning the patient, suctioning, and supporting

respirations. Inadequate amnesia or analgesia can make a

procedure more difficult; conversely, prolonged sedation

can occur with repeated doses of sedative agents. Careful

Seconds 30 min Can precipitate withdrawal in chronic users

medication titration and monitoring for effect can avoid

these complications.

SUGGESTED READING

American College of Emergency Physicians. Clinical policy for

procedural sedation and analgesia in the emergency department. Ann Emerg Med. 1 998;31:663-677.

Deitch K, Miner J, Chudnofsky CR, Dominici P, Latta D. Does

end tidal C02 monitoring during emergency department

procedural sedation and analgesia with propofol decrease the

incidence of hypoxic events? A randomized, controlled trial.

Ann Emerg Med. 201 0;55:258-264.

Green SM, Roback MG, Miner JR, Burton JH, Krauss B. Fasting

and emergency department procedural sedation and analge ­

sia: a consensus-based clinical practice advisory. Ann Emerg

Med. 2007;49:454-46 1.

Miner JR. Procedural sedation and analgesia. In: Tintinalli JE,

Stapczynski JS, Ma OJ, Cline DM, Cydulka, RK, Meckler GD.

Tintinalli's Emergency Medicine: A Comprehensive Study

Guide. 7th ed. New York, NY: McGraw-Hill, 20 1 1:283-29 1.