Mixed Deck — All MAC Topics Flashcards

Which peripheral nerve block approach provides optimal coverage for shoulder surgery?

Answer: Interscalene brachial plexus block

The interscalene approach to the brachial plexus targets C5-C6-C7 roots, providing optimal coverage for shoulder and proximal arm surgery.

What ASA physical status classification is assigned to a patient with well-controlled hypertension and no functional limitations?

Answer: ASA II

ASA II indicates a patient with mild systemic disease that does not limit functional capacity.

A patient with obstructive sleep apnea (OSA) requires what special consideration during preoperative planning?

Answer: Plan for potentially difficult airway and heightened respiratory monitoring

OSA is associated with a potentially difficult airway and increased sensitivity to opioids and sedatives, requiring enhanced monitoring plans.

Which colloid solution has been shown in multiple randomized controlled trials to significantly increase the risk of acute kidney injury and renal replacement therapy in critically ill patients?

Answer: Hydroxyethyl starch (HES)

The CHEST and 6S trials demonstrated that hydroxyethyl starch solutions significantly increase rates of acute kidney injury and need for renal replacement therapy in critically ill patients, leading to FDA safety warnings.

Which induction method is preferred for a pediatric patient with a full stomach requiring emergency surgery?

Answer: Rapid sequence induction with succinylcholine

Rapid sequence induction minimizes time to securing the airway and reduces aspiration risk in pediatric patients with full stomachs.

Which inhaled anesthetic has the fastest onset?

Answer: Desflurane

Desflurane has the fastest onset among common inhaled anesthetics due to its very low blood-gas partition coefficient. This low solubility means that it is minimally absorbed into the blood and tissues, allowing it to rapidly reach the brain and exert its anesthetic effects. Consequently, patients achieve anesthesia quickly and also recover rapidly once administration is stopped.

Transfusion-associated graft-versus-host disease (TA-GvHD), a frequently fatal complication in immunocompromised patients, is prevented by:

Answer: Gamma irradiation of cellular blood products

Gamma irradiation (or pathogen-inactivation technology) inactivates donor T-lymphocytes within cellular blood products, preventing them from engrafting in an immunocompromised host and launching a graft-versus-host immune attack.

What is the appropriate induction dose of propofol in healthy pediatric patients compared to adults?

Answer: Higher mg/kg dose required

Children require higher weight-adjusted propofol induction doses (2.5-3.5 mg/kg) compared to adults (1.5-2.5 mg/kg) due to a larger volume of distribution.

Which aspect of anesthetic history is most critical to document during preoperative evaluation?

Answer: Prior neuraxial anesthesia complications

Prior neuraxial anesthesia complications such as post-dural puncture headache or neurological injury are essential to document and inform technique selection.

Which postoperative complication presents as high-pitched stridor and inspiratory difficulty in the PACU?

Answer: Post-extubation laryngeal edema or croup

Post-extubation stridor from laryngeal edema or subglottic croup presents as high-pitched inspiratory noise requiring nebulized epinephrine and steroid treatment.

What consciousness criterion from the modified Aldrete score must be met before PACU discharge?

Answer: Patient must respond to verbal commands

The consciousness criterion of the Aldrete score requires the patient to respond to verbal stimuli, indicating sufficient recovery from anesthetic agents for discharge.

At what gestational age are nociceptive pathways sufficiently developed for fetal pain response?

Answer: 24 weeks

Nociceptive pathways are sufficiently developed by approximately 24 weeks gestation for a fetal response to pain.

What is the purpose of adding epinephrine to a local anesthetic solution for nerve blocks?

Answer: Prolong duration and reduce systemic absorption via vasoconstriction

Epinephrine causes local vasoconstriction, reducing vascular absorption of the local anesthetic and prolonging block duration while decreasing systemic toxicity risk.

Which preoperative test is routinely indicated for a healthy 35-year-old male undergoing elective inguinal hernia repair?

Answer: No routine tests required

Healthy ASA I patients undergoing low-risk procedures do not require routine preoperative laboratory testing per evidence-based guidelines.

What reduction in MAC occurs in pregnant patients compared to non-pregnant patients?

Answer: 30-40%

Pregnancy reduces MAC by approximately 30-40% due to elevated progesterone levels, which have CNS sedative properties.

A spinal block that ascends to T4 may block which critical physiologic response?

Answer: Cardiac accelerator fibers

Cardiac accelerator fibers originate from T1-T4; a spinal block to this level can cause significant bradycardia and hypotension.

What is the purpose of preoxygenation before induction of anesthesia?

Answer: Increase oxygen reserves

Preoxygenation, typically achieved by administering 100% oxygen for several minutes before induction of anesthesia, aims to denitrogenate the patient's functional residual capacity (FRC) and replace it with oxygen. This significantly increases the body's oxygen reserves, providing a longer period of safe apnea during induction and intubation. This extended 'apneic window' helps delay the onset of hypoxemia, enhancing patient safety.

A PACU patient has SpO2 88% with slow, shallow respirations after large fentanyl doses. What is the appropriate intervention?

Answer: Naloxone titration plus respiratory support

Opioid-induced respiratory depression is treated with careful titration of naloxone to restore ventilation without precipitating acute opioid reversal and pain crisis.

Which local anesthetic is most cardiotoxic?

Answer: Bupivacaine

Bupivacaine is recognized as the most cardiotoxic local anesthetic due to its strong binding to cardiac sodium channels and slow dissociation rate. This can lead to severe cardiac arrhythmias and myocardial depression, especially in cases of accidental intravascular injection. Its cardiotoxicity is a significant concern compared to other local anesthetics like lidocaine.

When should cricoid pressure be released during a rapid sequence induction?

Answer: After confirming correct endotracheal tube placement via capnography

Cricoid pressure should be maintained until correct ETT placement is confirmed by capnography and direct visualization, providing continuous aspiration protection.