Chapter 15: Sedation - Review Flashcards

Sedation (Chapter 15) Notes

Introduction

Sedation is a commonly used service across hospital environments. It calms patients and allows completion of diagnostic and interventional procedures that may otherwise require general anesthesia. Compared with general anesthesia, sedation can result in fewer side effects such as nausea and vomiting and may lead to shorter recovery times. The term sedation covers varying states of consciousness and responsiveness induced by medications administered by anesthesia professionals and, in some cases, nonanesthesia providers. Sedation exists on a continuum between analgesia and general anesthesia (see Fig. 15.1). Anesthesia providers are trained to tailor medications to achieve different depths of sedation and to manage the cardiopulmonary impacts of sedative/analgesic drugs. Because the cardiopulmonary responses to sedatives vary greatly among patients and can be unpredictable, providers must be capable of interventions such as reversing drug effects, providing airway support and ventilation, or escalating to general anesthesia when necessary. Monitored Anesthesia Care (MAC) refers to the administration of sedation by an anesthesia provider at any level of consciousness. The older terms “conscious sedation” or “numbing sedation” refer to the administration of minimal or moderate sedation by nonanesthesia providers who are credentialed by their institution. Sedation services span multiple disciplines and are endorsed by professional organizations such as the Centers for Medicare and Medicaid Services (CMS) and the American Society of Anesthesiologists (ASA). Guidelines from these organizations govern training, patient evaluation, monitoring, and equipment related to sedation.

DEFINITION OF TERMS

The ASA Task Force on Sedation Guidelines defines several depth levels:

Minimal Sedation (anxiolysis): A drug-induced state during which patients respond normally to verbal commands. Cognitive function and coordination may be impaired, but ventilatory and cardiorespiratory functions are unaffected.
Moderate Sedation/Analgesia: A drug-induced depression of consciousness during which patients respond purposefully to verbal commands, with or without light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is usually adequate. Cardiovascular function is usually maintained.
Deep Sedation/Analgesia: A drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully after repeated or painful stimulation. The patient may require assistance to maintain a patent airway, and spontaneous ventilation may be inadequate. Ventilatory and cardiovascular function may be impaired.
General Anesthesia: A drug-induced loss of consciousness in which patients are not arousable, even by painful stimulation. The airway may require intervention and mechanical ventilation may be necessary. Cardiovascular function may be impaired.

Table 15.1 (ASA Depth of Anesthesia Definitions) summarizes these categories and their typical physiologic features.

Table 15.1. American Society of Anesthesiology Depth of Anesthesia Definitions

Depth	Responsiveness	Airway	Spontaneous Ventilation	Cardiovascular Function
Minimal Sedation (Anxiolysis)	Normal response to verbal commands	Unaffected	Unaffected	Unaffected
Moderate Sedation/Analgesia (Conscious Sedation)	Purposeful response to verbal or tactile stimulation	No intervention required	Adequate	Usually maintained
Deep Sedation/Analgesia	Response may be limited; may require repeated stimulation	Intervention may be required to maintain airway	May be inadequate	May be impaired
General Anesthesia	Unarousable; not responsive	Airway management required	Often inadequate or absent	May be impaired

ASA Recommendations

Sedation is a continuum, and predicting an individual patient’s response is not always possible. Practitioners intending to produce a given level of sedation should perform a presedation evaluation, use standard monitoring equipment, and have support equipment available. Pre-sedation evaluation and preparation should include a focused physical examination (including an airway exam) and a review of pertinent medical history to improve the likelihood of a satisfactory sedation and reduce complications. For example, patients who do not adhere to preoperative fasting guidelines are at higher risk for pulmonary complications such as aspiration and are not ideal candidates for sedation.

All sedation cases require standard ASA monitors to be applied prior to sedation and observed throughout the administration of sedation and until the patient recovers. Monitoring includes assessment of cardiovascular status (blood pressure, heart rate) and oxygenation, with continuous monitoring of capnography (EtCO2) and, where appropriate, ventilation. In the out-of-operating-room (OOR) setting, a monitoring system is available for non-OR procedures, including rapid detection of airway obstruction and ventilatory compromise. Ready access to alarmed airways, suction, and resuscitation equipment is essential. Anesthesia providers are trained to assess the impact of sedatives and analgesics, intervene if necessary, and mitigate adverse effects. Reversal medications for opioids and benzodiazepines should be readily available (e.g., naloxone and flumazenil).

MONITORING AND PREPARATION

(Standard monitoring and safety equipment are essential for all sedations.)

Monitoring: Pre- and intra-procedure monitoring includes blood pressure, heart rate, oxygen saturation, and EtCO2. Additional monitoring may be used in the out-of-OR setting depending on the procedure and patient risk.
Airway readiness: Equipment and drugs for airway management should be readily available, and personnel should be prepared to escalate to general anesthesia if needed.
Rescue equipment and reversal medications: Positive pressure ventilation capability, suction, and reversal agents (e.g., naloxone for opioids; flumazenil for benzodiazepines) must be accessible.
Staffing: An anesthesia professional should supervise moderate and deeper levels of sedation, especially when using agents with higher risk profiles (e.g., propofol).

MEDICATION SELECTION

No single medication has all ideal properties for every sedation scenario. The goal is rapid onset and offset, reliable analgesia and/or anxiolysis, cardiovascular and respiratory stability, minimal nausea, and ease of titration. In practice, anesthesia providers often administer a combination of agents.

Propofol: A sedative frequently used for sedation cases. It can be given as a single bolus or titrated as an infusion. It provides rapid onset and clearance and may reduce nausea and vomiting. However, propofol carries a risk of hypotension and apnea and is generally recommended to be administered by an anesthesia provider due to these risks.
Dexmedetomidine: An α2-adrenergic agonist with sedative and analgesic properties. It may preserve respiratory drive and has utility in ICU settings and selective procedures (e.g., FOB, mechanical ventilation). It is not limited to the ICU and can be useful in patients where respiratory preservation is important, though it can cause bradycardia and hypotension.
Ketamine: A dissociative anesthetic that provides sedation and analgesia while maintaining ventilatory drive and cardiovascular stability. It is useful in settings where pain relief is needed but opioids are not suitable. Adverse effects include hallucinations, hypersalivation, and emergence delirium.
Ketamine is especially valuable when there is risk of cardiac or respiratory compromise.
Benzodiazepines (e.g., midazolam, Versed): Used to reduce anxiety and provide amnesia, commonly in moderate and deep sedation. They can cause paradoxical reactions in elderly patients.
Opioids (e.g., fentanyl, alfentanil): Provide analgesia during moderate to deep sedation. They have rapid onset and clearance but carry risks of respiratory depression and are synergistic with benzodiazepines, increasing respiratory depression risk.
Reversal agents: Naloxone for opioids, Flumazenil for benzodiazepines, used as safety measures during sedation, particularly when nonanesthesia professionals perform moderate sedation.

Common Case Considerations

Sedation is widely used for various procedures, including:

Gastrointestinal procedures (basic endoscopy to advanced interventional endoscopy): Sedation with benzodiazepines and opioids can be effective for moderate sedation; propofol infusions are used for deep sedation and rapid recovery.
Interventional radiology (IR) procedures: Often performed outside the OR with specialized monitoring and equipment; many procedures are percutaneous and cause minimal postprocedure pain; sedation helps maintain patient stillness and comfort during longer or more challenging procedures.
Magnetic Resonance Imaging (MRI): Anxiety, claustrophobia, and discomfort due to positioning may necessitate sedation. MRI requires careful coordination since the patient is remote from the anesthesia provider; a combination of benzodiazepines and sedative infusions is common. See Chapter 52 (MRI Safety) for environment-specific considerations.
Regional anesthesia and nerve blocks: Sedation may be used during blocks to improve safety and comfort. If block success is unlikely or if the patient tolerates only a light sedation, the anesthesiologist may need to escalate to deeper anesthesia or general anesthesia.

SUMMARY

Sedation exists on a continuum from minimal to deep sedation and general anesthesia and is provided widely across hospital settings by anesthesia and nonanesthesia providers.
Advances in monitoring and the availability of reversible medications have increased the safety and reliability of sedation.
Anesthesia providers are trained to recognize and manage the cardiovascular and respiratory effects of sedatives and analgesics.
Institutional and organizational guidelines govern all aspects of sedation, including training, pre-sedation evaluation, monitoring, and equipment requirements.

REVIEW QUESTIONS

1) When providing moderate sedation for a patient, the anesthesia provider is:

A) Not permitted to use propofol
B) Expecting the patient to be able to maintain his or her own airway
C) Not required to record vital signs as often as for other anesthetics
D) Not required to perform a physical examination prior to the case
E) None of the above

Answer sketch: The correct stance is B — patients under moderate sedation should be able to maintain their own airway with minimal adjuncts; all sedation cases require appropriate evaluation and monitoring.

2) Dexmedetomidine is used for providing sedation for procedures:

A) Only in cardiac cases
B) When the surgeon or endoscopist wants the patient deeply sedated
C) For procedures that are not painful, but amnesia is very important
D) Where preservation of respiratory function is important
E) Only in the ICU

Answer: D – Dexmedetomidine provides sedation with preserved respiratory function, and while highly validated in ICU settings, it is not exclusive to ICU use.

3) The American Society of Anesthesiologists recommends that propofol:

A) Should only be used for deep sedation
B) Should only be used for induction and maintenance of general anesthesia
C) Should only be used with a controlled infusion
D) Should only be used by an anesthesia provider

Answer: D – Propofol is used for both sedation and induction/maintenance of general anesthesia, but due to its risk profile (hypotension, apnea), it is recommended to be administered by an anesthesia provider.

4) Match the drug to its unique property

Versed
Fentanyl
Ketamine
Propofol
Options:
A) Reversible with naloxone
B) Dissociative and analgesic
C) Often causes hypotension
D) Risks paradoxical reaction in the elderly

Proposed matches: Versed → D (paradoxical reactions in the elderly), Fentanyl → A (reversible with naloxone), Ketamine → B (dissociative and analgesic), Propofol → C (often causes hypotension).

ADDITIONAL RECOMMENDED READINGS

American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology. 2002;96:1004-1017.
Continuum of Depth of Sedation: Definition of General Anesthesia and Levels of Sedation/Analgesia. Committee on Quality Management and Departmental Administration. Approved by the ASA House of Delegates on October 27, 2004; amended October 21, 2009.
Standards for Basic Anesthetic Monitoring. Committee of Origin: Standards and Practice Parameters. Approved by the ASA House Delegates on October 21, 1986; last amended 2015.

Introduction

Sedation is a commonly used service across hospital environments, playing a crucial role in patient comfort and procedure completion. It calms patients and allows completion of diagnostic and interventional procedures that may otherwise require general anesthesia, addressing issues like anxiety, pain, and the need for immobility. Compared with general anesthesia, sedation can result in fewer side effects such as nausea and vomiting and may lead to shorter recovery times, making it a favorable option for many patients.

The term sedation covers varying states of consciousness and responsiveness induced by medications. These medications are administered by anesthesia professionals and, in some cases, nonanesthesia providers. Sedation exists on a continuum between analgesia and general anesthesia, meaning the depth can range from very light calming to a state very close to general anesthesia (see Fig. 15.1).

Anesthesia providers are extensively trained to tailor medications to achieve specific depths of sedation and to manage the complex cardiopulmonary impacts of sedative/analgesic drugs. Because the cardiopulmonary responses to sedatives vary greatly among patients and can be unpredictable, providers must be capable of critical interventions such as reversing drug effects, providing advanced airway support and ventilation, or escalating to general anesthesia when necessary to ensure patient safety.

Monitored Anesthesia Care (MAC) refers to the administration of sedation by an anesthesia provider at any level of consciousness. This implies continuous presence and readiness for any level of intervention. The older terms “conscious sedation” or “numbing sedation” refer to the administration of minimal or moderate sedation by nonanesthesia providers who are credentialed by their institution, with specific limitations on drug types and patient risk profiles. Sedation services span multiple medical disciplines and are endorsed by professional organizations such as the Centers for Medicare and Medicaid Services (CMS) and the American Society of Anesthesiologists (ASA), whose guidelines govern training, patient evaluation, monitoring, and equipment related to safe sedation practices.

DEFINITION OF TERMS

The ASA Task Force on Sedation Guidelines defines several depth levels, each with distinct physiological responses requiring different levels of vigilance and intervention:

**Minimal Sedation (anxiolysis)**: A drug-induced state during which patients respond normally to verbal commands. Cognitive function and coordination may be impaired, but ventilatory and cardiorespiratory functions are unaffected. This is essentially a mild tranquilized state where the patient is still fully aware and cooperative.
**Moderate Sedation/Analgesia**: A drug-induced depression of consciousness during which patients respond purposefully to verbal commands, with or without light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is usually adequate. Cardiovascular function is usually maintained. Patients in this state are relaxed and drowsy but can still engage if prompted.
**Deep Sedation/Analgesia**: A drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully after repeated or painful stimulation. The patient may require assistance to maintain a patent airway, and spontaneous ventilation may be inadequate. Ventilatory and cardiovascular function may be impaired. This level requires a higher degree of monitoring and preparedness for intervention.
**General Anesthesia**: A drug-induced loss of consciousness in which patients are not aroused, even by painful stimulation. The airway may require intervention (e.g., intubation), and mechanical ventilation may be necessary. Cardiovascular function may be impaired, often requiring pharmacologic support.

Table 15.1 (ASA Depth of Anesthesia Definitions) summarizes these categories and their typical physiologic features.

Table 15.1. American Society of Anesthesiology Depth of Anesthesia Definitions

Depth	Responsiveness	Airway	Spontaneous Ventilation	Cardiovascular Function
Minimal Sedation (Anxiolysis)	Normal response to verbal commands	Unaffected	Unaffected	Unaffected
Moderate Sedation/Analgesia (Conscious Sedation)	Purposeful response to verbal or tactile stimulation	No intervention required	Adequate	Usually maintained
Deep Sedation/Analgesia	Response may be limited; may require repeated stimulation	Intervention may be required to maintain airway	May be inadequate	May be impaired
General Anesthesia	Unarousable; not responsive	Airway management required	Often inadequate or absent	May be impaired

ASA Recommendations

Sedation is a continuum, and predicting an individual patient’s exact response to sedative medications is not always possible due to varying patient physiology and comorbidities. Therefore, practitioners intending to produce a given level of sedation should perform a comprehensive presedation evaluation, use standard monitoring equipment, and have robust support equipment readily available.

Pre-sedation evaluation and preparation should include a focused physical examination (e.g., cardiac, pulmonary, and a thorough airway exam to assess for difficult airway features) and a review of pertinent medical history (e.g., allergies, previous anesthetic experiences, current medications, cardiovascular or pulmonary disease). This detailed assessment aims to improve the likelihood of a satisfactory sedation outcome and significantly reduce potential complications. For example, patients who do not adhere to preoperative fasting guidelines are at higher risk for pulmonary complications such as aspiration of gastric contents and are generally not ideal candidates for elective sedation, potentially requiring postponement or alternative anesthetic plans.

All sedation cases require standard ASA monitors to be applied prior to sedation initiation and observed continuously throughout the administration of sedation and until the patient recovers fully. Monitoring includes assessment of cardiovascular status (continuous electrocadiogram (ECG), blood pressure, heart rate) and oxygenation (pulse oximetry, SpO2). Continuous monitoring of capnography (EtCO CO_2 detection) is crucial as it provides an early and direct indicator of ventilatory status and can detect airway obstruction or hypoventilation before changes in SpO2 occur. Where appropriate, direct ventilation monitoring is also employed. In the out-of-operating-room (OOR) setting, specialized monitoring systems are increasingly available for non-OR procedures, including rapid detection of airway obstruction and ventilatory compromise, often incorporating technologies suited for remote or challenging environments. Ready access to alarmed airways (like oral or nasal airways), efficient suction, and resuscitation equipment (e.g., defibrillator, emergency drugs) is essential for timely intervention.

Anesthesia providers are specifically trained to assess the dynamic impact of sedatives and analgesics on patient physiology, intervene proactively if necessary, and mitigate adverse effects. Reversal medications for common sedative classes like opioids and benzodiazepines should be readily available (e.g., naloxone for opioid overdose and flumazenil for benzodiazepine reversal) to counteract profound respiratory depression or oversedation rapidly.

MONITORING AND PREPARATION (Standard monitoring and safety equipment are essential for all sedations.)

Ensuring comprehensive monitoring and preparation is paramount for patient safety across all levels of sedation.

**Monitoring**: Pre- and intra-procedure monitoring includes continuous ECG, non-invasive blood pressure, heart rate, oxygen saturation (SpO2), and end-tidal capnography (EtCO2). The EtCO_2 helps confirm adequate ventilation and early detection of respiratory depression. Additional monitoring (e.g., temperature, urine output) may be used depending on the complexity of the procedure and patient risk in the out-of-OR setting.
**Airway readiness**: A full complement of equipment and drugs for advanced airway management (e.g., oral/nasal airways, laryngoscopes, endotracheal tubes, laryngeal mask airways, emergency cricothyrotomy kit) should be readily available. Personnel must be prepared to escalate to general anesthesia, including securing the airway, if the patient's condition deteriorates.
**Rescue equipment and reversal medications**: The capability for positive pressure ventilation (bag-valve-mask with oxygen), an efficient wall or portable suction apparatus, and reversal agents (e.g., naloxone for opioids; flumazenil for benzodiazepines) must be immediately accessible and clearly labeled.
*\oStaffing*\o: An anesthesia professional (anesthesiologist or certified registered nurse anesthetist) should supervise moderate and deeper levels of sedation, especially when using agents with higher risk profiles (e.g., propofol) that can rapidly transition to general anesthesia.