Analgesia and Sedation

Laura E. Lehrian, DO

Sarah Gerken, MD

The need for anesthesia, analgesia, or sedation provided for gastroenterological procedures has evolved in parallel with the types of procedures being performed, as well as with the increasing complexity of patients requiring those procedures. The goal of sedation or anesthesia in endoscopic procedures is to achieve an appropriate level of patient comfort during the procedure, while maintaining hemodynamic stability and patient safety. Practice guidelines for nonanesthesiologists providing sedation have been published by the American Society of Anesthesiologists (ASA) Committee for Sedation and Analgesia by Non-Anesthesiologists, and the guidelines have been approved by the American Society for Gastrointestinal Endoscopy (ASGE).¹

To strike a balance between sedation and safety, the physician responsible for patient care must understand the patient factors that can influence the course of the procedure, as well as the sedation they are providing. Prior to performing a procedure, a thorough evaluation of preexisting medical comorbidities, current medications and drug allergies, previous sedation/anesthesia history, current vital signs, as well as a history and physical should be undertaken. Many factors can influence a patient’s response to sedation medications and these include, but are not limited to, disease states of organ systems (renal, hepatic, neurologic, cardiac, and respiratory impairment), obstructive sleep apnea, obesity, substance abuse, and chronic use of certain medications (opioids, benzodiazepines, etc.). The ASA has provided a patient physical status classification that reflects a patient’s comorbid conditions and general fitness for undergoing anesthesia and procedures; a recent study demonstrated that an increasing ASA classification was associated with higher prevalence of serious adverse events for upper endoscopy.²

ASA CLASSIFICATION

I	The patient is normal and healthy.
II	The patient has mild systemic disease that does not limit activities (e.g., controlled hypertension or controlled diabetes without systemic sequelae).
III	The patient has moderate or severe systemic disease that does not limit activities (e.g., stable angina or diabetes with systemic sequelae).
IV	The patient has severe systemic disease that is a constant threat to life (e.g., severe congestive heart failure, end-stage renal failure).
V	The patient is moribund and is at a substantial risk of death within 24 hours (with or without a procedure).
E	Emergency status: in addition to indicating the underlying ASA status (I-V), any patient undergoing an emergency procedure is indicated by suffix “E.”

Patients with a history of problems with anesthesia or sedation, stridor, snoring or obstructive sleep apnea, rheumatoid arthritis, or certain chromosomal abnormalities may present problems with airway management, if that were to become necessary. In addition to those conditions, patients with certain physical characteristics can be associated with difficult airway management. Some of these characteristics may include a short, thick neck; limited head and neck mobility; dysmorphic facial features; small mouth opening; a high, arched palate; micrognathia; and retrognathia.³

The Mallampati Classification

Class I	Hard palate, soft palate, uvula
Class II	Hard palate, soft palate, portion of uvula
Class III	Hard palate, soft palate, base of uvula
Class IV	Hard palate only

The sedation level required for each procedure and each patient will vary every time. Levels of sedation are described from minimal sedation (anxiolysis) to general anesthesia. With increasing sedation, there will be increasing requirements to be able to intervene and rescue a patient if a level of sedation becomes deeper than intended. In minimal sedation, a patient is able to respond to commands and respiratory and cardiovascular status is unaffected. Moderate sedation (formerly “conscious” sedation) will allow a patient to respond purposefully to light stimuli as well as to verbal commands, with unaffected respiratory and cardiovascular functions. Deep sedation results in a patient who cannot be easily aroused but can respond purposefully with repeated or painful stimulation; here, the ability to maintain a patent airway
and spontaneous ventilation may be inadequate and may require ventilatory support. General anesthesia results in loss of consciousness during which time patients are not arousable even to painful stimuli; here, assistance in maintaining the airway is typically necessary, and it is important to note that cardiovascular function may be impaired.

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