Conscious sedation is a clinical technique that creates a decreased level of awareness for a patient yet maintains protective reflexes, adequate spontaneous ventilation, and the ability to respond appropriately to physical stimulation or verbal command. The goals of conscious sedation are to provide analgesia, amnesia, and anxiolysis during a potentially painful or frightening procedure. Conscious sedation is appropriate for both adult and pediatric patients, and a variety of drugs may be used to create the correct clinical effect.
Conscious sedation requires a specific standard of equipment, personnel, and training. Clinicians administering conscious sedation should be credentialed appropriately in the technique and should be competent to manage a patient’s airway if complications arise. Holding ACLS certification is desirable. Team personnel who will be providing assistance and monitoring of the patient should also be familiar with recovering patients from sedation and hold at least BCLS certification. Patients selected for this technique should be generally healthy, with no significant comorbid conditions. The American Society of Anesthesiologists (ASA) has devised a standard physical status classification that is shown in
Table 70.1. It is appropriate that you examine your patient and assign him or her to an ASA class before the procedure. Be sure to document the physical examination and ASA classification.
Conscious sedation in the urgent care setting is appropriate for Class I patients as well as selected Class II patients. It is not appropriate for Class III or higher patients. Patients in ASA classification III or greater should be referred to a consultant for sedation in an operating room environment. Patients who have eaten within 2 to 4 hours of the procedure should also be excluded because of the risk for aspiration of gastric contents.
Pharmacologic agents used in conscious sedation are of three general classes: sedatives, analgesics, and systemic anesthetics. Pure sedatives will provide amnesia and anxiolysis but no analgesia, if a painful procedure is to be performed. Analgesics provide pain relief, and in some cases they provide some sedation. Using a combination of sedative-analgesic generally provides a synergistic combination, which will give consistent clinical results, and generally uses smaller dosages of each agent. Use of a systemic anesthetic provides very rapid sedation with some analgesia.
This chapter will illustrate reliable and simple techniques to provide conscious sedation for adult and pediatric patients in the urgent care setting, using standard, generally available equipment and pharmacologic agents.
What You Need
Monitoring equipment: (a) blood pressure cuff, (b) cardiac monitor, and (c) pulse oximeter
Resuscitation equipment: (a) suction, (b) intravenous access equipment, (c) oxygen, nasal cannula or mask, (d) airway management equipment (endotracheal tubes, laryngoscopes, airways), (e) bag and mask, (f) defibrillator, (g) emergency cardiac resuscitation medications, (h) naloxone, and (i) flumazenil
Personnel: (a) clinical personnel trained in airway, and (b) management, general patient care, resuscitation
Sedative agents (IV): (a) diazepam OR, (b) lorazepam OR, (c) midazolam
Analgesic agents (IV): (a) meperidine OR, (b) morphine OR, (c) fentanyl
Systemic anesthetics: (a) ketamine (IM or IV use) and (b) propofol (IV use only)
Adjunctive medications: atropine
Clinical Technique
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Obtain a relevant medical history from the patient and perform a physical examination to include the cardiorespiratory system, as well as the injured area. Make an assessment of ASA classification. Do indications for conscious sedation exist? Could another, less complex technique be substituted? Does the patient understand what you are going to do and why? Obtain consent as clinically appropriate.
If Proceeding,
Discuss the procedure with your clinical team and assign roles. Assign one team member to OBSERVE THE PATIENT’S VITAL SIGNS, AIRWAY PATENCY, AND ADEQUACY OF VENTILATION AS HIS OR HER ONLY RESPONSIBILITY.
Connect patient to monitoring equipment: pulse oximeter, cardiac monitor, blood pressure monitor (or cuff). Obtain baseline readings. Providesupplemental oxygen for the patient through nasal cannula or a mask. Pulse oximetry and heart rate should be monitored constantly; bloodpressure and level of consciousness (LOC) should be monitored every5 minutes.
ORAL CONSCIOUS SEDATION
The major advantage of the oral route is that it is generally pain-free. Disadvantages include irregular absorption of the agent (because of gastric emptying time, food in the stomach, or hepatic extraction), leading to uneven sedation results, and a generally longer lead time until sedation has begun.
Either oral diazepam (0.1 to 0.3 mg/kg) or oral midazolam (0.5 to 0.75 mg/kg) are reasonable choices. Both of these agents are available as flavored liquid suspensions, so they can be used easily in pediatric patients. Time to peak effect may be anywhere from 10 to 30 minutes, with duration of action from 20 to 60 minutes. The oral route is appropriate for procedures that do not need to be approached with haste.
INTRAMUSCULAR CONSCIOUS SEDATION
Intramuscular (IM) conscious sedation is probably the simplest technique with predictable, timely, and effective results for both adult and pediatric patients. For pediatric patients, ketamine with adjunctive atropine (and midazolam if desired) provides excellent sedation and analgesia. For adults, a sedative plus an adequate dose of analgesic is often quite effective.
Using Ketamine
Ketamine combined with atropine and midazolam is a very effective combination, providing sedation within 5 to 10 minutes, lasting usually for 30 to 60 minutes, and in some cases for up to 120 minutes. Using atropine reduces salivation and tracheobronchial secretions, whereas using the midazolam improves the level of sedation, reduces emergence reactions (dreaming, confusion), and reduces the total dose of ketamine used.
Using a Sedative Plus an Analgesic
A sedative plus an analgesic is an effective and simple technique for adults.
INTRAVENOUS CONSCIOUS SEDATION
Intravenous (IV) conscious sedation techniques provide rapid onset of conscious sedation with a moderate offset. It is necessary to establish an IV line, which allows for precise titration of medications to obtain clinical effectiveness. Intravenous conscious sedation may be used in both pediatric and adult patients.
Ketamine + Atropine + Sedative
REVERSAL OF DRUGS USED IN CONSCIOUS SEDATION
Specific agents are available for the reversal of the effects of benzodiazepines and opioids. Reversal of these agents may be required if the sedation becomes deeper than is warranted. These agents should be readily available during the sedation procedure. There are no reversal agents for ketamine or propofol.
Benzodiazepines may be reversed by flumazenil, which is a competitive antagonist of these agents.
Dosage: 10 mcg/kg IV/IM/SC every 1 to 2 minutes to total dose of 1 mg
Onset/Offset: Onset is 1 to 2 minutes, lasting for 6 to 10 minutes
Maximum: Up to 1 mg every 20 minutes, maximum 3 mg in 1 hour
Note that flumazenil has a shorter duration of action than most benzodiazepines. Observe patient for 2 hours after reversal to detect benzodiazepine resedation.
Opioids may be reversed with naloxone, which is a competitive antagonist of these agents.
Dosage: 1 to 2 mcg/kg IV/IM/SC every 2 to 3 minutes to reverse minor respiratory depression, 2 mg STAT IV/IM/SC to reverse respiratory arrest
Onset/Offset: 1 to 2 minutes onset, offset in 60 to 90 minutes
Naloxone has a shorter half-life than most opioids. Resedation may occur, requiring a subsequent dose of naloxone.
