Data viva — subanaesthetic ketamine as an analgesic adjunct

Stimulus

A table shows the opioid-sparing percentage, the effect on opioid-induced hyperalgesia, and the principal adverse effect for the common perioperative analgesic adjuncts: ketamine (opioid consumption reduced with longer time to first analgesic across 70 randomised studies; NMDA anti-hyperalgesic; counters OIH; psychotomimetic and sympathomimetic; no respiratory depression — taught); lidocaine, dexmedetomidine, magnesium and gabapentinoid with their taught comparator percentages and principal hazards (confirm standard text for non-ketamine rows). Interpret the table, rank the adjuncts by evidence strength and opioid-sparing magnitude, and defend a choice for (a) a major abdominal case and (b) an opioid-tolerant chronic-pain patient.