Procedural Sedation for APRNs Nursing CE Course

ion and manage its consequences (i.e., managing a compromised airway or hypoventilation and supporting cardiovascular function in patients who become hypertensive, hypotensive, bradycardic, or tachycardic). With MAC, the administration of sedative or analgesic medications may be similar to moderate PSA; however, a qualified anesthesia provider (anesthesiologist or CRNA) of MAC is focused exclusively and continuously on the patient (i.e., monitoring for airway compromise or hemodynamic changes) and must be prepared and qualified to convert to general anesthesia if necessary. Therefore, moderate PSA is a proceduralist-directed service (by MDs, PAs, dentists, or APRNs) that separate institutional policies govern. In comparison, a qualified anesthesia provider directs MAC to administer a maximal depth of sedation above that provided by moderate PSA. The complexity of the procedure, the anticipated level of sedation needed, and the patient’s comorbid conditions can be used to determine whether moderate PSA or MAC should be used (ASA, 2018a, 2018b).  

The role of APRNs in PSA procedures can vary based on state and facility policies. Healthcare facilities should consult their state board of nursing regarding regulatory requirements for medication administration, assessment, and monitoring patients receiving PSA. Given the significant increase in the demand for sedation services, the use of non-anesthesia professionals is becoming more widespread. The AANA (2016) sets policy considerations for PSA administered by a non-anesthesia provider (MDs, PAs, dentists, or APRNs) and registered nurse (RN) sedation team. PSA administration requires specific provider competencies (i.e., pre-sedation assessment and evaluation, patient education, cardiovascular monitoring, drug selection and administration, management of potential adverse reactions or complications, and post-sedation recovery). The policies, procedures, and accountability for PSA administration within a healthcare facility should occur within a single organized anesthesia service. Regardless of their facility type, all HCPs must be aware of the statutes, regulations, and standards that govern their licensure, facility, and clinical practice (AANA, 2016).

The Society of Gastroenterology Nurses and Associates (SGNA, 2017) published a position statement on the use of sedation and analgesia in GI endoscopy procedures, defining a GI RN as either an APRN or RN. Education for a non-anesthesia provider responsible for supervising or directly administering moderate PSA must include training about the safe administration of sedation and analgesia medications. In addition, an APRN or RN who administers moderate PSA must recognize the signs and symptoms of progression into deep sedation. The specialized training required of a non-anesthesia provider administering and monitoring patients receiving PSA must include Advanced Cardiac Life Support (ACLS) certification, prior training in moderate sedation, and successful completion of a propofol sedation curriculum. A propofol sedation-training curriculum must include initial and periodic retraining, including airway management, patient safety, and simulation. According to the SGNA (2017), RNs trained and experienced in GI nursing and endoscopy can administer and maintain moderate PSA according to the orders and supervision of a physician with appropriate credentialing and privileges. Gastrointestinal RNs monitor patients, assess PSA maintenance, and document patient status throughout each endoscopic procedure (SGNA, 2017).

Various professional organizations have put forth numerous guidelines highlighting PSA indications, the definition of sedation as a continuum, and the role of and training expectations for non-anesthesia providers (Tran et al., 2019). CMS has delegated institutions to address the minimum qualifications and supervision requirements for each category of HCP permitted to provide PSA. Each institution must develop a guideline for PSA, ideally in collaboration with the department of anesthesiology. Key recommendations by all professional organizations include the following: 2 providers should be present at all times during sedation (i.e., the sedation provider and the proceduralist), the sedation provider should focus solely on the administration of medication and monitoring the patient, and specialized training should be given to all sedation practitioners (i.e., RNs, APRNs, and PAs). Training must include an understanding of moderate versus deep sedation, approved sedatives, emergent life support (i.e., ACLS), airway management skills (i.e., face mask and positive pressure ventilation), pre-procedural evaluation (i.e., history and physical examination), and monitoring and documentation (i.e., pulse oximetry, blood pressure [BP], electrocardiogram [ECG], heart rate [HR], and capnography; Tran et al., 2019). 

The American Association of Moderate Sedation Nurses (AAMSN) is a professional organization that provides a sedation certification examination for RNs. Certified Sedation Registered Nurses (CSRNs) are APRNs or RNs who earn a sedation certification by taking an advanced curriculum focused on patient assessment, pharmacology, airway, monitoring, equipment, emergencies, emergence, clinical judgment, and critical thinking. It is within the scope of RN practice to manage patients receiving moderate PSA under the guidance of a non-anesthesia provider with qualifications in education, licensure, and certification. CSRNs are legally responsible for sedation care determined by their state board of nursing; position statements for individual state policies can be found at the sedationcertification.com website in the Resources section (AAMSN, n.d.).

Anatomy and Physiology

Before any PSA procedure, an airway examination is critical to prevent complications. Knowledge of the airway anatomy and various anomalies allows HCPs to anticipate respiratory complications. Respiratory failure from airway obstruction or hypoventilation is a severe complication associated with sedation procedures (Benzoni & Cascella, 2021). Several characteristics increase the likelihood of airway compromise or inadequate ventilation during PSA (e.g., abnormal facial features, significant body habitus, facial injury, and decreased cervical spine mobility). A Mallampati score can be used to predict airway compromise or inadequate ventilation and is best used as a part of a global airway assessment. The Mallampati score relates the mouth opening to the size of the tongue (see Figure 1). This classification, ranging from I to IV, predicts the ease of intubation (i.e., class I or II is easy, class III is challenging, and class IV is extremely difficult; Brown et al., 2021). 

Indications and Contraindications

PSA may be used for any procedure during which pain or anxiety may be excessive or impede the success of an intervention or diagnostic procedure. The level of sedation needed depends upon the patient’s predicted pain or anxiety and their need to remain motionless during the procedure. Standard procedures where PSA may be beneficial include: closed joint reduction, complicated laceration repair, abscess incision or drainage, electrical cardioversion, lumbar puncture, endoscopy, dental procedures, or wound debridement. Individualized treatment plans must include the risks and benefits of utilizing PSA outside of the operating room (OR) compared to controlled sedation in the OR (Benzoni & Cascella, 2021; Chawla et al., 2017; Frank et al., 2020). 

Although there are no absolute contraindications to PSA, factors that increase the risk of adverse events include older age, significant medical comorbidities, obesity, and signs of a difficult airway. The HCP and patient should discuss the potential benefits of PSA versus the risks of adverse events. Elderly patients are not excluded from PSA but have a higher risk of aspiration and an increased sensitivity to sedation and analgesic drugs. Patients with specific medical comorbidities have a greater risk of experiencing the respiratory and cardiovascular depressant effects of sedation, including heart failure, neuromuscular disease, anemia, and chronic obstructive pulmonary disease (COPD; Benzoni & Cascella, 2021; Frank et al., 2020). The ASA Physical Status Classification System assesses a patient’s medical comorbidities and predicts perioperative risks. The classification system should be used while also considering the type of procedure, frailty, and the patient’s level of conditioning. See Table 1 for the ASA Physical Status Classification System (ASA, 2020). 

The addition of “E” to the numerical classification (IE, IIE, etc.) indicates an emergency surgery (when the delay in the surgery would lead to a significant increase in threat to life or body part). Additional criteria for the classification system are available for pediatric and obstetric patients (ASA, 2020). A conservative approach to PSA medications should be taken to reduce the risk of adverse events among older adults and patients with comorbid conditions (e.g., giving a lower starting dose, using slower administration rates, and repeating doses of medications less frequently). In addition, reducing the risk of aspiration is a priority for elderly patients and patients with comorbid conditions during PSA procedures (Frank et al., 2020). According to the ACEP, providers of unscheduled PSA should assess the timing and nature of recent oral intake (Green et al., 2019). In the 2018 guidelines, the ACEP consensus statement suggested that fasting before PSA is unnecessary for preventing aspiration of gastric contents in most cases. Although there is no evidence that longer fasting times reduce aspiration risk, it may be reasonable to wait if the procedure is not an emergency (Green et al., 2020). Longer fasting periods should be considered for patients with high aspiration risks (i.e., conditions predisposing to esophageal reflux, extreme ages [<6 months or >70 years], severe systemic disease [ASA class III or greater], obstructive sleep apnea [OSA], or obesity; Frank et al., 2020). In the ASA Committee on Standard of Practice Parameters (2018) guidelines, a fasting period of at least 2 hours for liquids and 6 hours for solid foods should be used for adults undergoing elective PSA procedures. 

Pre-Procedure Planning

PSA risks can be minimized by ensuring the proper pre-procedural preparation has been completed. Pre-procedural preparation should verify adequate personnel and equipment and a thorough history and physical examination (Tran et al., 2019). In addition, the ASA (2018) guidelines recommend consultation with a medical specialist when needed, patient preparation (i.e., informed consent and pre-procedure education), and pre-procedure fasting as indicated. 

Informed Consent

Before performing PSA, an HCP must discuss the purpose of the therapeutic or diagnostic procedure with the patient. In addition, the clinician must discuss the risks, benefits, and alternatives of the therapeutic or diagnostic procedure and the use of PSA. The patient and their family member/caregiver should be allowed to ask questions, and patient preferences should be incorporated into the individualized treatment plan. When a patient is actively involved in the treatment plan discussion, patient anxiety and the risk of adverse events are reduced. Informed consent for the diagnostic or therapeutic procedure and PSA should be obtained and documented in the medical record. Implied consent is acceptable in certain circumstances when a patient cannot provide consent due to altered mental status or severe pain (AANA, 2016; ASA, 2018; Frank et al., 2020). For elective procedures, patients should be educated on the ASA guidelines for fasting as described above. In urgent or emergent situations when gastric emptying is impossible, do not delay PSA based on fasting time alone (ASA, 2018).

History and Physical Examination

A thorough review of a patient's medical record, health history, and physical examination before PSA can prevent adverse events or patient harm. This pre-procedure assessment can help determine whether the patient is a good candidate for moderate PSA. HCPs should review medical records and interview the patient or their family to identify the following: 

• abnormalities of the major organ systems (i.e., cardiac, renal, pulmonary, neurologic, sleep apnea, metabolic, and endocrine)
• adverse experience with previous sedation or analgesia, including regional and general anesthesia
• history of a difficult airway
• current medications (i.e., prescription, over-the-counter (OTC), and herbals), drug allergies, and potential drug interactions
• history of tobacco, alcohol, or substance use or abuse
• frequent or repeated exposure to sedation or analgesic agents
• NPO status or timing of last liquid and food intake (ASA, 2018)

In addition to a thorough health history review, a pre-procedure physical examination should be performed. If this is an elective procedure, the pre-procedural evaluation should be completed in advance to allow for consultation with a medical specialist if needed. This evaluation should then be repeated immediately before the procedure. For all pre-procedure assessments, the clinician should evaluate the patient’s height, weight, BMI, laboratory and diagnostic data, and vital signs. In addition, a comprehensive head-to-toe assessment should be completed and documented, focusing on the neurologic, cardiac, and respiratory systems. The ASA Physical Status Classification System should be used to calculate an ASA score. If the patient is determined to have significant comorbidities or an ASA classification of unstable ASA III, ASA IV, or higher, the nurse or HCP should consult anesthesiology to determine the most appropriate care (AANA, 2016; ASA, 2018; Fencl, 2016). As discussed above, the risk of airway compromise or inadequate ventilation can be assessed using a Mallampati score, with class III or IV indicating the more significant threat (ASA, 2020). Additionally, APRNs should consult anesthesiology for patients who are being followed by palliative care, have a history of chronic opioid use, have a history of not tolerating sedation, are unable to lie still for the duration of the procedure, have a history of difficult intubation, or have a condition requiring management beyond two providers (Tran et al., 2019).

Personnel

As discussed above, HCPs performing PSA should have a comprehensive understanding of the continuum of sedation and the mechanism of action, doses, side effects, and reversal agents of appropriate medications. The number of clinicians needed to perform PSA safely may vary depending on the patient’s health status and the complexity of the therapeutic or diagnostic procedure. In most cases, the sedation team will consist of a clinician who performs the procedure and another clinician (e.g., RN) who administers the sedative and analgesic medications and monitors the patient’s vital signs and clinical status. The clinician assigned to administer the medications and monitor the patient should not assist with the procedure (Frank et al., 2020). Although not always practical, a dedicated team of trained clinicians to provide PSA is likely to provide the safest care to the patient. The multidisciplinary team of healthcare providers may include a physician team leader, a proceduralist (physician, APRN, or PA), a sedation provider (APRN or RN), a respiratory therapist (when possible), a scribe, and ancillary staff as needed (e.g., radiology tech). Although the members of the sedation team may vary from case to case, the pre-procedural huddle (role delineation and time out) and post-procedural debrief can ensure patient safety and high-functioning team performance (Chawla et al., 2017).

Equipment

Proper pre-procedure planning ensures that all necessary equipment to perform the PSA and manage the airway is available at the bedside. Equipment used in PSA should be inspected and confirmed to be in working order before use (SGNA, 2017). Such equipment can include the following:

• airway equipment (bag-valve mask [BVM], appropriately sized oral and nasal airways, and equipment to perform endotracheal intubation)
• suction equipment to manage oral secretions or vomiting
• resuscitation medications, including ACLS medications and reversal agents
• oxygen administration equipment (nasal cannula and non-rebreather mask)
• intravenous equipment to establish a functional saline lock
• monitoring equipment (telemetry, blood pressure cuff, pulse oximetry, and capnography if available; Benzoni & Cascella, 2021; Frank et al., 2020)

 Intraprocedural Assessment and Monitoring

Many of the complications associated with moderate PSA can be avoided with frequent assessment, monitoring, and documentation throughout the entire procedure (ASA, 2018). The intraprocedural phase should begin with a “time out” before the start of the procedure. The sedation team should confirm the correct patient, procedure, and site. In addition, the “time out” chief can help ensure all documents are complete, equipment is available, and any concerns are addressed (AANA, 2016). A procedural sedation checklist should be used to verify that all safety checks have been completed throughout the curse of the procedure. Individual organizations may modify existing checklists to align with the practice setting and institutional policies. The AORN (2019) comprehensive surgical checklist is an example based on guidelines from The Joint Commission (TJC) and the World Health Organization (WHO). The ASA (2018) guidelines recommend the following strategies for intraprocedural patient monitoring:

• monitoring their level of consciousness based on their response to verbal and tactile stimuli
• monitoring patient ventilation and oxygenation utilizing capnography and pulse oximetry
• hemodynamic monitoring (blood pressure, heart rate, and electrocardiography)
• contemporaneous recording of monitored parameters
• availability of an individual responsible for patient monitoring

Each of these strategies is discussed in greater detail below.

As discussed earlier, sedation occurs on a continuum, and the transition between sedation levels is not clearly defined. Therefore, periodic evaluation (e.g., at 5-minute intervals) of patient responsiveness to verbal and tactile stimuli and vital signs can help identify the level of sedation. During PSA procedures where verbal responses are not possible (e.g., oral surgery or endoscopy), check the patient’s ability to give a “thumbs up.” See Table 2 for the ASA (2018) guidelines for determining the level of sedation.

HCPs who are administering PSA medications should continually monitor patient ventilation and oxygenation. Monitoring ventilatory function can be done by observing respiratory rate and depth, capnography, and pulse oximetry (ASA, 2018). Capnography (i.e., end-tidal carbon dioxide) monitors the partial pressure of carbon dioxide (CO2) of expired respiratory gases. The body uses oxygen to produce energy and releases CO2 into the blood transported to the lungs. The quantity of CO2 depends on the sufficiency of circulation to the lungs, with low end-tidal CO2 possibly indicating poor perfusion. However, continuous end-tidal capnography monitoring for PSA is controversial. According to the ACEP (2014), there is a lack of evidence that capnography reduced the incidence of serious adverse events during PSA (i.e., neurologic injury caused by hypoxia, aspiration, or death). However, the ASA (2018) recommends continuous capnography during moderate PSA procedures based on research that patients experienced fewer hypoxemic events when capnography was used. 

 Hemodynamic monitoring should occur routinely throughout the intraprocedural period. Blood pressure should be noted before the start of sedation and analgesia. Once moderate sedation and analgesia are initiated, clinicians should monitor blood pressure at 5-minute intervals until the patient has fully recovered (i.e., 30 minutes after the last dose of sedation). Electrocardiographic monitoring (telemetry) should be continually monitored for arrhythmias. Clinicians should record the patient’s level of consciousness, ventilatory and oxygenation status, and hemodynamic status (ASA, 2018). The frequency of documentation depends on the patient's condition, type and amount of medication, and procedure length. The ASA (2018) guidelines have suggested that documentation should occur before administering sedation or analgesic medications, after administration of the medications, at regular intervals during the procedure, at the initial recovery stage, and just before discharge. Supplemental oxygen during moderate PSA is recommended to maintain oxygen reserves and prevent hypoxemia unless contraindicated for the patient or procedure (Frank et al., 2020). 

Medications

PSA typically involves the IV administration of sedative, dissociative, or opioid drugs or a combination of these medications. The choice of drugs for PSA will depend on the patient, the procedure, and the anticipated procedure length. Ideal medications for PSA have a rapid onset, have a short duration of action, maintain hemodynamic stability, and do not cause significant adverse effects (Frank et al., 2020). The patient’s response to these medications may vary based on physical status, age, weight, comorbidities, and medication history. Therefore, the appropriate selection of medications and dosage should be specific to the individual patient. Administer the smallest dose necessary to achieve the appropriate level of sedation, making incremental increases as needed (AANA, 2016). The ASA (2018) guidelines provided recommendations regarding the medications to be used in moderate PSA.

Opioids

Opioids produce analgesia by binding to opioid receptors (mu, gamma, and kappa) to inhibit neurotransmitter release. Opioids are metabolized through the CYP3A4 pathways and are renally excreted. Fentanyl is a rapid-onset (1 to 2 minutes) and short-acting (30 to 60 minutes) synthetic opioid metabolized by the liver. Fentanyl, used in combination with midazolam, was the preferred sedation and analgesia approach to PSA before propofol and etomidate became widely available. Dosing for IV administration in adults and children is 1 to 1.5 mcg/kg and then titrated to 1 mcg/kg every 3 minutes until the desired effect is reached. Fentanyl is usually given as a slow IV push in doses of 0.5 to 1 mcg/kg every 2 minutes. The maximum total dose is generally 5 mcg/kg, but higher doses may be needed in certain circumstances. Fentanyl rarely causes hypotension; however, respiratory depression can occur. Respiratory depression can be potentiated when combined with a sedative. Older adults or patients with renal or hepatic disease can experience more profound and prolonged effects with fentanyl. Therefore, smaller doses and slower titration should be considered (ASA, 2018; Frank et al., 2020; Tran et al., 2019).

Other short-acting opioids used for PSA include remifentanil and alfentanil. These agents are similar in structure to fentanyl, with a rapid onset and a duration of action of approximately 5 minutes. In addition, remifentanil and fentanyl are comparable in potency, but alfentanil is only about one-fifth to one-tenth as potent as fentanyl. Therefore, there are no published guidelines for the use of alfentanil as the sole agent in PSA. Instead, alfentanil may be used as an adjunct with propofol at a dose of 2.5 mcg/kg, repeating every 2 minutes as needed. By contrast, remifentanil may be used alone or in combination with propofol for moderate PSA. When used alone, the initial dose is 0.5 to 3 mcg/kg, and subsequent doses of 0.25 to 1 mcg/kg may be given every 2 minutes as needed. When used in combination with propofol, remifentanil is dosed at 0.5 mcg/kg over 1 minute, with subsequent doses of 0.25 mcg/kg given every 1 to 2 minutes as needed (ASA, 2018; Frank et al., 2020).

Benzodiazepines

Benzodiazepines depress the CNS by binding to gamma-aminobutyric acid receptors (GABA), producing anxiolytic and amnesic effects with no analgesic properties. They are renally metabolized and require a dose reduction for patients with renal or hepatic dysfunction. Benzodiazepines are commonly used for minimal sedation or in combination with a short-acting opioid for moderate PSA. Midazolam is the most widely used benzodiazepine because of its ability to penetrate the blood-brain barrier quickly, with an onset of 2 to 5 minutes and a duration of 32 to 60 minutes. In adults, midazolam is given in doses of 0.02 to 0.03 mg/kg (usually 0.5 or 1 mg) IV over 1 to 2 minutes, with repeated doses every 2 to 5 minutes as needed. For anxiolysis, a single dose of 0.02 mg/kg is usually sufficient. Midazolam accumulates in adipose tissue, which can significantly prolong sedation. Therefore, older adults and patients with obesity, renal conditions, or hepatic disease should start at lower doses with a longer duration between repeated doses. In most circumstances, no more than 5 mg of midazolam is needed for PSA. If a diagnostic or therapeutic procedure has a longer anticipated timeframe, an alternative agent such as propofol should be considered. Midazolam can cause respiratory depression at high doses and when combined with opioids. Other benzodiazepines such as lorazepam or diazepam, which have a relatively prolonged onset and duration of action, are less suited for PSA. When given in combination with an opioid, it is recommended to administer midazolam first with fentanyl then carefully titrated to reduce the risk of respiratory depression (ASA, 2018; Frank et al., 2020; Tran et al., 2019). 

Propofol

 Propofol is a lipophilic compound that interacts with GABA receptors to produce hypnotic and amnesic effects but has no analgesic properties. With rapid redistribution into the peripheral tissues, propofol is considered an ultra fast-acting drug (i.e., onset within 1 minute). In addition to the rapid onset, a single dose of propofol typically wears off within minutes; however, repeated doses can be used for prolonged sedation. The liver metabolizes propofol, but the plasma levels remain unchanged in patients with renal or liver dysfunction. In contrast, older adults tend to have increased plasma levels, prolonging sedation and cardiorespiratory depression. Propofol can induce deep sedation rapidly, and there is no reversal agent; therefore, careful attention to dosing and monitoring is critical. The rapid onset and duration of propofol make it a desirable choice for PSA. However, clinicians must be trained explicitly in propofol administration and should refer to their state licensing board and institutional policies outlining who can administer and monitor a patient receiving propofol. For PSA in adults, propofol should be given at an initial dose of 0.5 to 1 mg/kg via a slow IV push (20 mg over 10 seconds). Repeat doses should be 0.25 to 0.5 mg/kg every 1 to 3 minutes as needed to reach the desired level of sedation. Dosing for older adults should be reduced by 20% and given over 3 to 5 minutes. Propofol can produce side effects such as hypoxia, hypotension, hypoventilation, and apnea, and these effects can be potentiated if administered with other sedatives or analgesics (ASA, 2018; Frank et al., 2020; Tran et al., 2019).

Etomidate

Etomidate is an imidazole derivative that produces hypnotic and amnesic effects but has no analgesic properties. For PSA, etomidate often requires the co-administration of an analgesic (e.g., fentanyl), which increases the risk of respiratory depression. Etomidate has an immediate onset of action and a duration of 5 to 15 minutes. A benefit of using etomidate is that it maintains cardiovascular stability; however, it can have profound and prolonged effects in older adults in patients with renal or hepatic dysfunction. For adults, etomidate is given in doses of 0.1 to 0.15 mg/kg IV over 30 to 60 seconds. The same dose can be readministered every 3 to 5 minutes as needed. Potential side effects with etomidate administration include myoclonus (sudden jerky movements or muscle spasms), respiratory depression, adrenal suppression, and nausea and vomiting. Myoclonus may be related to subcortical disinhibition and has been reported in up to 80% of patients receiving etomidate for PSA. Since myoclonus could impact the success of the therapeutic or diagnostic procedure, other medications may be preferred (ASA, 2018; Frank et al., 2020).

Ketamine

Ketamine is a phencyclidine-derived anesthetic that produces a trance-like state and provides sedation, amnesia, and analgesia. In addition, ketamine inhibits the N-methyl-D-aspartate (NMDA) receptors to produce CNS depression and dissociation while preserving airway muscle tone, airway protective reflexes, and spontaneous breathing. It is often used for brief, painful procedures (e.g., fracture reduction or laceration repair) because of its excellent sedative and analgesic properties, rapid onset (1-5 minutes), and short duration of action (10 to 20 minutes). For adults, a dose of 1 to 2 mg/kg is given IV over 1 to 2 minutes, with subsequent doses of 0.25 to 1 mg/kg repeated every 5 to 10 minutes. The reported side effects of ketamine can include hypertension, laryngospasm, tachycardia, nausea and vomiting, increased intracranial pressure, increased intraocular pressure, and hypersalivation. Although cardiorespiratory effects are rare, caution should be exercised for patients with hypertension. In addition, ketamine should be avoided for patients with schizophrenia, as it has been shown to exacerbate this condition. The most commonly reported side effect of ketamine is emergence reactions, described as disorientation, dream-like experiences, or hallucinations. Emergence reactions occur in up to 20% of adults but tend to be self-limiting and require no pharmacologic treatment. Administering a low dose of midazolam (0.05 mg/kg) IV slowly over 1 to 2 minutes before administering ketamine can prevent emergence reactions (ASA, 2018; Frank et al., 2020; Tran et al., 2019). 

Dexmedetomidine

Dexmedetomidine, an alpha-2 agonist that acts at the locus coeruleus in the pons to reduce the release of norepinephrine, is a relatively new anesthetic medication for PSA that has predictable cardiovascular, analgesic, and sedative effects (when used with propofol or ketamine). Unlike other sedatives, muscle tone and respiratory drive are preserved with dexmedetomidine. It is frequently used for sedation of mechanically ventilated patients in the ICU but does not appear to have any distinct advantage over other sedative agents for PSA. The onset of action is under 5 minutes with a duration of 1 to 2 hours. When used for PSA, dexmedetomidine is given as an IV infusion of 0.2 to 0.7 mcg/kg/hr, with a 0.5 to 1 mcg/kg bolus given over 10 minutes before the start of the infusion. In addition, dexmedetomidine can be used for minimal sedation and is administered intranasally in doses of 2 to 3 mcg/kg. When used alone, it can produce unpredictable levels of sedation and amnesia, and there is an increased risk of bradycardia and hypertension. When dexmedetomidine is combined with propofol or ketamine, more effective sedation occurs, and cardiovascular depression is minimized (ASA, 2018; Frank et al., 2020; Tran et al., 2019).

Methohexital

Methohexital is a barbiturate that suppresses the reticular activating system in the brainstem and cerebral cortex, producing sedative and amnesic effects. Methohexital has an immediate onset and duration of 10 minutes and is often used in combination with opiates. The initial dose is 0.75 to 1 mg/kg IV, with repeat doses of 0.5 mg/kg given every 2 minutes as needed. Side effects can include myocardial depression, which can lead to hypotension and tachycardia. In addition, it can precipitate or exacerbate seizures and should not be given to patients with underlying seizure disorders. Etomidate and propofol are often preferred over methohexital (ASA, 2018; Frank et al., 2020). 

Nitrous Oxide

Nitrous oxide is a gas that causes CNS depression and euphoria with little to no effect on respiratory function. It is used frequently for minimal sedation (e.g., pediatric dentistry) because of its rapid onset of action and swift recovery. Nitrous oxide is inhaled as a 30% to 50% mixture, with 30% oxygen (at 5 to 6 L/min) to avoid hypoxemia. The concentration of nitrous oxide should not exceed 50%. The benefits of nitrous oxide include its minimal side effects, and the gaseous route of administration eliminates the need for an IV. A well-ventilated room is needed to prevent clinician exposure during administration (Benzoni & Cascella, 2021; Frank et al., 2020).

Complications

Although serious complications related to PSA rarely occur, appropriate preparation, assessment, and monitoring are essential for patient safety. The most common adverse outcomes include respiratory depression, cardiovascular instability, vomiting, aspiration, emergence reactions, and inadequate sedation preventing the completion of the procedure. Complications can be prevented through appropriate screening of patients, proper sedative and analgesic medication selection, and careful monitoring during each procedure. In addition, alternative sedation methods should be considered for patients at risk of airway compromise or inadequate ventilation. Nearly all sedative agents for PSA can cause dose-dependent respiratory depression; therefore, supplemental oxygen should be utilized during each procedure. Treatment with reversal agents such as naloxone (for opioids) or flumazenil (for benzodiazepines) may be necessary for severe or prolonged respiratory depression (Frank et al., 2020). After the pharmacologic reversal, observe and monitor patients for a sufficient time to ensure sedation and cardiorespiratory depression do not reoccur (ASA, 2018).

Post-Procedure and Discharge

Patients receiving moderate PSA can continue to be at risk for developing complications after completing the procedure. Therefore, the ASA (2018) has outlined recommendations for post-procedure recovery care, including:

• After sedation and analgesia, observe and monitor patients in an appropriately staffed and equipped area until they are near their baseline level of consciousness and no longer at risk of cardiorespiratory depression.
• Monitor oxygenation continuously until patients are no longer at risk of hypoxemia.
• Monitor ventilation and circulation at regular intervals (every 5 to 15 minutes) until patients are suitable for discharge.
• Design discharge criteria to minimize the risk of subsequent CNS or cardiorespiratory depression.

In addition to these recommendations, each facility should create post-procedure guidelines and discharge instructions. The guidelines should include the frequency of patient assessment, evaluation, monitoring, and documentation in the recovery period. A designated, qualified HCP (APRN or RN) capable of managing complications should remain in the procedure area until the patient is stable. Specific criteria that signify the patient may be ready for discharge include a return to baseline mental status, stable vital signs, an adequate time since the last dose of sedation and analgesia medications, absence of nausea, and sufficient pain management (Fencl, 2016). Upon discharge from the facility, each patient should receive detailed verbal and written instructions regarding their diet, medications, and activities to facilitate recovery. In addition, discharge instructions should include information about potential complications, management of complications, and contact information if they have questions or need assistance (AANA, 2016).

References

American Association of Moderate Sedation Nurses. (n.d.). Registered nurse (CSRN) scope of practice. Retrieved July 30, 2021, from https://aamsn.org/resources/pdfs/sedation-related-pdfs/registered-nurse-csrn-scope-of-practice

American Association of Nurse Anesthetists. (2016). Non-anesthesia provider procedural sedation and analgesia: Policy considerations. https://www.aana.com/docs/default-source/practice-aana-com-web-documents-(all)/professional-practice-manual/non-anesthesia-provider-procedural-sedation-and-analgesia.pdf?sfvrsn=670049b1_4

American Association of Nurse Anesthetists. (2021). Certified registered nurse anesthetists fact sheet. https://www.aana.com/membership/become-a-crna/crna-fact-sheet

American College of Emergency Physicians Clinical Policies Committee. (2014). Clinical policy: Procedural sedation and analgesia in the emergency department. Annals of Emergency Medicine, 63(2), 247-258. http://dx.doi.org/10.1016/j.annemergmed.2013.10.015

American Society of Anesthesiologists. (2018a). Distinguishing monitored anesthesia care (“MAC”) from moderate sedation/analgesia (conscious sedation). https://www.asahq.org/standards-and-guidelines/distinguishing-monitored-anesthesia-care-mac-from-moderate-sedationanalgesia-conscious-sedation

American Society of Anesthesiologists. (2018b). Position on monitored anesthesia care. https://www.asahq.org/standards-and-guidelines/position-on-monitored-anesthesia-care

American Society of Anesthesiologists. (2020). ASA physical status classification system. https://www.asahq.org/standards-and-guidelines/asa-physical-status-classification-system

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