Question

MAC will be the lowest in which of the following clinical scenarios?

A. A 28-week premature infant presenting for an exploratory laparotomy
B. A term infant presenting for a tracheoesophageal fi stula repair 7
C. A 6-month-old infant presenting for circumcision
D. A 40-year-old woman presenting for a total abdominal hysterectomy
E. A 75-year-old man presenting for a total hip arthroplasty

Answer 1

MAC will be lowest in a 28-week premature infant because of their increased sensitivity to anesthetics due to immature organ systems and a more permeable blood-brain barrier.

Step-by-step explanation:

The student is asking about Minimum Alveolar Concentration (MAC), which indicates the potency of anesthetic agents and is influenced by several patient factors. In this clinical scenario, MAC will be the lowest for a 28-week premature infant presenting for an exploratory laparotomy. Premature infants typically have a higher sensitivity to anesthetic agents due to their immature organ systems, specifically the nervous system and liver, which are crucial for anesthetic metabolism and elimination. The immature blood-brain barrier in premature infants also allows for more efficient CNS penetration by anesthetics, lowering the MAC. In comparison to other groups mentioned, premature infants require the least amount of anesthetic agent to achieve the desired effect of preventing movement in response to noxious stimuli.