MAC

POA EXAM 4

Definition of Monitored Anesthesia Care (MAC)?

A procedure in which an anesthesia provider provides preoperative evaluation, care during the procedure, and post-procedural management.

How does the clinical standard of care for MAC compare to general anesthesia?

It requires the exact same standard of care as any other anesthetic technique.

What is the most common cause of death or central nervous system injury during MAC?

Respiratory compromise caused by over-sedation.

Primary medication classes responsible for impairing respiratory function during MAC?

Sedatives and opioids.

What unique clinical capability differentiates MAC from standard conscious or procedural sedation?

It allows for deeper sedation with the distinct ability to convert to general anesthesia.

Providers typically permitted to perform procedural or conscious sedation?

Non-anesthesia providers including ED physicians, RNs, ICU staff, endoscopists, and dentists.

Why does a loss of consciousness during a MAC case demand extra care and immediate intervention?

To monitor the airway closely and prevent airway mishaps.

What are two primary physiologic advantages of MAC over general anesthesia?

It invokes less physiological disturbance and allows for a more rapid recovery.

What medication delivery strategy should be used during MAC to avoid over-sedation?

Titrate medications in small increments or utilize continuous infusion pumps.

Can a single anesthetic agent satisfy all components of a Monitored Anesthesia Care framework?

No, no single medication can provide all components of MAC.

What three elements combine to form the surgical fire triangle responsible for face and neck burns during MAC?

An oxidizer (supplemental O2), an ignition source (electrocautery), and fuel (alcohol prep or drapes).

What are the five core components of MAC defined by the ASA guidelines?

Pre-anesthesia evaluation, direction of care level, provider plan participation, continued presence, and emergency availability.

What specific steps are required to test the anesthesia breathing system for leaks and confirm positive-pressure ventilation capability?

Occlude the patient end of the system, fill it with oxygen using the flush valve, and apply manual pressure to the distended reservoir bag.

Baseline monitors required independent of the selected anesthetic technique?

Blood pressure, pulse oximetry, electrocardiography (ECG), and capnography.

What are the three core drug choices listed for general anesthesia induction?

Propofol, thiopental, and etomidate.

What four continuous infusion or bolus opioids are routinely prepared before anesthesia induction?

Fentanyl, sufentanil, alfentanil, and remifentanil.

Which two benzodiazepines are standardly prepared for preoperative or intraoperative sedation?

Midazolam and diazepam.

Which two anticholinergic drugs are prepared to manage bradycardia or secretions?

Atropine and glycopyrrolate.

Which two sympathomimetic vasopressors are kept available to treat acute hypotension?

Ephedrine and phenylephrine.

What specific depolarizing neuromuscular blocking drug is routinely prepared for rapid intubation?

Succinylcholine.

What four nondepolarizing neuromuscular blocking drugs are routinely available for surgical relaxation?

Rocuronium, vecuronium, cisatracurium, and pancuronium.

Which two anticholinesterase drugs are prepared to reverse nondepolarizing muscle relaxants?

Neostigmine and edrophonium.

What emergency catecholamine must always be available to treat a severe acute allergic reaction?

Epinephrine.

What eight items constitute the core advanced airway and monitoring equipment list for routine preparation?

Oral/nasal airway, laryngeal mask airway (LMA), tracheal tube, nasogastric tube, suction catheter, IV solution/tubing, vascular cannula, and temperature probe.

What five standard monitoring parameters must be utilized by the anesthesia provider during a MAC case?

ECG, pulse oximetry, capnography, NIBP (non-invasive blood pressure), and temperature.

What two actions must be taken regarding the oxygen analyzer before anesthesia induction?

Calibrate the oxygen analyzer with air and oxygen, and set the appropriate alarm limits.

What structural element of the anesthesia machine must be visually inspected for color change prior to induction?

The carbon dioxide absorbent.

What is the standard fasting time window required for clear liquids prior to an elective surgery induction?

2 hours.

What specific liquid substance is strictly excluded from the 2-hour clear liquid fasting allowance?

Alcohol.

What is the mandatory fasting duration required after consuming breast milk before induction?

4 hours.

What is the required fasting time frame for infant formula or nonhuman milk prior to elective surgery?

6 hours.

What is the required fasting duration after eating a light meal such as toast or cereal?

6 hours.

What is the minimum fasting time requirement for heavy, fatty meals, fried food, or meat?

8 hours or more.

What are the two specific clinical guidelines regarding the use of chewing gum before surgery induction?

Chewing gum is allowed up until induction, but you must confirm its removal prior to induction.

What type of fluid should healthy adults be encouraged to drink up to 2 hours prior to an elective surgery?

Carbohydrate-containing clear liquids.

To what specific patient population and case type do these standard ASA fasting guidelines apply?

Healthy patients who are not in labor and are undergoing elective surgery.

What is the strict intake directive for a patient during the final 2 hours immediately preceding an anesthesia induction?

No solids and no liquids.

What six unique patient traits, pathologies, or symptom complexes are evaluated during a focused preoperative assessment for MAC?

Cooperation/command-following, ability to remain still in position, cognitive dysfunction, baseline respiratory symptoms (cough/DOE/orthopnea), expected airway difficulty, and patient expectations.

What specific responsiveness baseline defines the deep sedation/analgesia level on the continuum of depth of sedation?

A purposeful response following repeated or painful stimulation.

How do the airway and spontaneous ventilation needs differ between moderate sedation and deep sedation levels?

Moderate sedation requires no airway intervention and spontaneous ventilation is adequate, whereas deep sedation may require airway intervention and spontaneous ventilation may be inadequate.

What responsiveness baseline defines the state of general anesthesia on the continuum of depth of sedation?

The patient is unarouseable even with a painful stimulus.

What parameter defines the context-sensitive half-time (CSHT) pharmacological property of an intravenous drug?

The time required for the plasma drug concentration to decrease by 50 percent after terminating a continuous infusion of a specific duration.

What principal receptor and what specific autonomic property characterize Propofol use during MAC cases?

Acts on GABA receptors and provides intrinsic antiemetic effects.

What are the recommended continuous infusion maintenance dose and the prn bolus dose ranges for Propofol during MAC?

The continuous infusion dose is 25 to 75 mcg/kg/min, and the bolus dose is 0.25 to 0.5 mg/kg.

How does the context-sensitive half-time (CSHT) of Midazolam compare directly to that of Propofol?

The CSHT of Midazolam is twice as long as that of Propofol.

Why is the chemical solubilizing vehicle propylene glycol a high-yield clinical differentiator between Midazolam and Diazepam?

Midazolam is water-soluble and does not require it, whereas Diazepam requires propylene glycol which causes significant pain on injection and venoirritation.

What are the specific elimination half-life and metabolite differences between Midazolam and Diazepam?

Midazolam has a short half-life of 1 to 4 hours with inactive metabolites, while Diazepam has a long half-life exceeding 20 hours with active metabolites (desmethyldiazepam, oxazepam).

Why is resedation more likely to occur post-procedurally with Diazepam administration compared to Midazolam?

Diazepam possesses a prolonged elimination half-life and yields active metabolites, whereas Midazolam possesses a short half-life and yields inactive metabolites.

What is the specific mechanism of action of Flumazenil?

A competitive benzodiazepine receptor antagonist that reverses the central nervous system effects of benzodiazepines.

What are the initial intravenous dose and the maximum cumulative ceiling dose parameters for Flumazenil administration?

The initial dose is 0.2 mg IV, repeatable every 45 to 60 seconds up to a maximum cumulative dose of 1 mg.

Why must the anesthesia provider monitor a patient closely for resedation following successful Flumazenil administration?

The clearance and duration of action of the administering benzodiazepine may exceed the duration of action of Flumazenil.

What specific drug class and dosing parameters define Ketamine administration across IV, IM, and oral routes?

Phencyclidine derivative given as 0.25 to 1 mg/kg IV, 2 to 4 mg/kg IM, or 4 to 6 mg/kg orally.

Why must a benzodiazepine like midazolam be co-administered when giving Ketamine at doses exceeding 0.5 mg/kg?

To prevent hallucinations.

What are two key absolute contraindications or cautions for Ketamine based on pressure dynamics?

Increased intracranial pressure (ICP) and increased intraocular pressure (IOP) from globe injuries.

What are the standard onset time and total duration of action (DOA) for a baseline Ketamine dose?

Onset is 1 to 2 minutes, and duration of action is 60 minutes.

What are three clinical settings or high-risk patient conditions where a Ketamine induction is highly favored?

Shock/cardiovascular instability, hypovolemia, cardiomyopathy, trauma, or bronchospasm.

What are the recommended continuous infusion and supplemental bolus dose parameters for Ketamine maintenance?

Continuous IV infusion of 15 to 45 mcg/kg/min (1 to 3 mg/min) or 0.5 to 1.0 mg/kg supplemental IV doses as needed.

What is the primary mechanism of action class for Dexmedetomidine?

Alpha-2 receptor agonist.

What are two principal cardiovascular side effects associated with continuous Dexmedetomidine administration?

Bradycardia and hypotension.

What are the initial loading dose parameters and the standard maintenance infusion rate for Dexmedetomidine?

Loading dose of 0.5 to 1 mcg/kg over 10 to 15 minutes, followed by a maintenance infusion of 0.2 to 0.7 mcg/kg/hour.

How do the subhypnotic analgesic and amnestic properties of Dexmedetomidine compare directly to Propofol?

Dexmedetomidine has analgesic properties but insignificant amnestic properties, whereas Propofol has minimal analgesic properties but significant amnestic properties.

What direction and what specific physiological mechanism explain the effect of opioids on the carbon dioxide response curve?

Shifts the CO2 response curve to the right by decreasing the brain's ventilatory drive/responsiveness to hypercapnia.

What are the standard duration of action, effect-site equilibrium time, and bolus dose parameters for Fentanyl?

Duration is 20 to 40 minutes, effect-site equilibrium time is 4 to 5 minutes, and the dose is a 25 to 50 mcg bolus.

How do the onset of action, duration, and effect-site equilibrium time of Alfentanil compare directly to Fentanyl?

Alfentanil has a more rapid onset of action, shorter duration, and a shorter effect-site equilibrium time of 0.6 to 1.2 minutes.

What are the specific macro weight-based bolus dose guidelines for Alfentanil use across MAC, induction, and intubation?

MAC cases use 5 mcg/kg, anesthesia induction uses 15 mcg/kg, and intubation workflows use 30 mcg/kg.

What unique context-sensitive half-time (CSHT) and effect-site equilibrium time define the pharmacokinetics of Remifentanil?

A short context-sensitive half-time of 3 to 5 minutes and an effect-site equilibrium time of 1 to 1.5 minutes.

What three life-threatening or severe cardiorespiratory side effects can occur following a rapid Remifentanil bolus?

Bradycardia, respiratory depression, and chest wall rigidity.

What are the exact bolus and infusion dosing parameters for Remifentanil running alone versus running with other medications?

Bolus dose is 12.5 to 25 mcg; infusion rate is 0.025 to 0.25 mcg/kg/min with other medications or 0.2 to 2 mcg/kg/min if running alone.

What is the specific mechanism of action and primary clinical reversal goal of Naloxone?

A pure opioid antagonist used to reverse opioid-induced respiratory depression and analgesia.

What three severe, potentially fatal adverse physiological responses can occur following rapid high-dose Naloxone administration?

Discomfort, pulmonary edema, and death triggered by profound catecholamine release causing ventricular fibrillation (V-fib).

What are the exact dilution preparation instructions and small incremental dosing parameters used to safely administer Naloxone?

Dilute a standard 0.4 mg/ml vial in 9ml of saline to create a 0.04 mg/ml concentration, then administer 0.04 to 0.08 mg (1 to 2 ml) at a time.

What anatomical muscles are sensitive to sedatives, causing upper airway collapse during MAC?

Upper airway dilator muscles.

What three respiratory complications frequently result from upper airway collapse under sedation?

Apnea, hypoxemia, and hypercarbia.

What five specific patient conditions or demographic traits increase the risk of airway collapse during MAC?

Obesity, OSA (obstructive sleep apnea), COPD/respiratory disease, elderly status, and neuromuscular disorders.

What is the effect of sedative and narcotic medications on protective airway reflexes?

They depress protective laryngeal and pharyngeal reflexes.

What specific reduction in the swallowing reflex occurs with the administration of Nitrous Oxide?

A 50% reduction.

What clinical depth-of-sedation strategy should be maintained to minimize the risk of aspiration?

Maintain the lightest plane of sedation.

What is the definitive anesthetic management change required if a patient presents a significant risk of aspiration?

Convert to general anesthesia (GA).

What are the two primary etiologies or mechanisms that cause Local Anesthetic Systemic Toxicity (LAST)?

Unintended intravascular injection of local anesthetic or rapid systemic absorption of local anesthetic.

What are the nine major patient, pathological, or procedural risk factors for developing LAST?

Extremes of age (

What nine central nervous system signs and symptoms characterize the progressive presentation of LAST?

Tinnitus, circumoral numbness, metallic taste, agitation, dysarthria, seizures, loss of consciousness, and respiratory arrest.

What four cardiovascular system signs and symptoms characterize the severe presentation of LAST?

Hypotension, bradycardia, ventricular arrhythmias, and cardiovascular collapse.

What specific systemic effects occur at a plasma lidocaine concentration of 1 to 5 mcg/mL?

Analgesia.

What specific systemic effects occur at a plasma lidocaine concentration of 5 to 10 mcg/mL?

Lightheadedness, tinnitus, and numbness of the tongue.

What specific systemic effects occur at a plasma lidocaine concentration of 10 to 15 mcg/mL?

Seizures and unconsciousness.

What specific systemic effects occur at a plasma lidocaine concentration of 15 to 20 mcg/mL?

Coma and respiratory arrest.

What specific systemic effect occurs at a plasma lidocaine concentration exceeding 25 mcg/mL?

Cardiovascular depression.

What is the very first mandatory action to take if LAST is suspected?

Stop the local anesthetic injection or infusion.

What unique modification is required for individual epinephrine boluses during LAST resuscitation compared to standard ACLS?

Reduce individual epinephrine boluses to less than or equal to 1 mcg/kg.

Which four cardiovascular medication classes or specific drugs must be strictly avoided during LAST resuscitation?

Vasopressin, calcium channel blockers, beta blockers, and local anesthetics.

What specific medication is designated as the first-line antiarrhythmic drug of choice to manage LAST-induced arrhythmias?

Amiodarone.

What are the exact bolus and infusion parameters for 20% lipid emulsion therapy in a patient weighing 70 kg or more?

Bolus 100 mL IV over 2 to 3 minutes, followed by an infusion of 250 mL over 15 to 20 minutes.

What are the exact weight-based bolus and infusion parameters for 20% lipid emulsion therapy in a patient weighing less than 70 kg?

Bolus 1.5 mL/kg IBW IV over 2 to 3 minutes, followed by an infusion at 0.25 mL/kg/minute.

What two precise dosing changes must be instituted for lipid emulsion therapy if cardiovascular instability persists?

Repeat the bolus and double the infusion rate.

What is the minimum duration that a lipid emulsion infusion must be continued after achieving hemodynamic stability?

At least 15 minutes.

What is the absolute maximum recommended cumulative intravenous dose of 20% lipid emulsion?

Approximately 12 mL/kg IV.

Is propofol an acceptable clinical substitute or alternative vehicle for lipid emulsion therapy in LAST?

No, propofol is not a substitute for lipid emulsion.

What advanced circulatory support intervention should be instituted if LAST is completely unresponsive to lipid emulsion and standard ACLS?

Cardiopulmonary bypass.

What are the required post-stabilization observation timelines for a patient who experienced a LAST-induced seizure versus cardiovascular instability?

Monitor the patient for 2 hours after a seizure, and 4 to 6 hours after hemodynamic instability.

What are the two primary medical heat delivery devices associated with the generation of surgical fires?

Electrocautery units and surgical lasers.