Which intraspinal opioid dose would NOT be acceptable to administer with 12 mg bupivacaine for a cesarean section in a 60 kg parturient?

Which intraspinal opioid dose would NOT be acceptable to administer with 12 mg bupivacaine for a cesarean section in a 60 kg parturient?

• A. 25 µg fentanyl
• B. 5 µg sufentanil
• C. 0.25 mg morphine
• D. 60 mg meperidine

Answer: (D)

When planning spinal anesthesia for cesarean delivery, opioids are added to the local anesthetic to extend analgesia and improve comfort, but the dose and the chosen opioid matter because of safety for both mother and baby. Among the common intrathecal opioids, fentanyl and sufentanil are very lipid-soluble and used in small doses (fentanyl around 10–25 mcg, sufentanil around 2–5 mcg) to provide rapid analgesia with minimal hemodynamic disturbance. Morphine, given intrathecally in a low dose (about 0.15–0.25 mg), gives longer-lasting postoperative analgesia but carries a higher risk of delayed respiratory depression, so patients are observed longer. Meperidine given intrathecally is not routinely used, and a dose as large as 60 mg would be inappropriate. Such a high intrathecal dose markedly increases the risk of profound sedation and respiratory depression, and it isn’t aligned with current practice or safety profiles for neuraxial opioids. Therefore, this dose would not be acceptable with 12 mg bupivacaine in a 60 kg parturient.

When planning spinal anesthesia for cesarean delivery, opioids are added to the local anesthetic to extend analgesia and improve comfort, but the dose and the chosen opioid matter because of safety for both mother and baby. Among the common intrathecal opioids, fentanyl and sufentanil are very lipid-soluble and used in small doses (fentanyl around 10–25 mcg, sufentanil around 2–5 mcg) to provide rapid analgesia with minimal hemodynamic disturbance. Morphine, given intrathecally in a low dose (about 0.15–0.25 mg), gives longer-lasting postoperative analgesia but carries a higher risk of delayed respiratory depression, so patients are observed longer.

Meperidine given intrathecally is not routinely used, and a dose as large as 60 mg would be inappropriate. Such a high intrathecal dose markedly increases the risk of profound sedation and respiratory depression, and it isn’t aligned with current practice or safety profiles for neuraxial opioids. Therefore, this dose would not be acceptable with 12 mg bupivacaine in a 60 kg parturient.