The effect of intrathecal morphine dose on outcomes after elective caesarean delivery: a meta-analysis. AA Apr 2016.
This meta-analysis compared low dose (LD 50-100microg) spinal morphine to high dose (HD >100-250microg) as part of spinal anaesthesia for elective Caesarean section. 11 Articles found including 480 patients. Primary outcome found HD (>100-250) spinal morphine prolonged mean time to first request for supplemental morphine equivalent by 4.5 hrs (CI 1.85–7.13 hours; P = 0.0008, Moderate heterogeneity) compared to LD (50-100). Secondary outcomes - incidence of pruritis and PONV was significantly lower in LD group (OR 0.34 p =0.0001, OR 0.44 p = 0.002 respectively) but pain scores at 12 hours, morphine equivalent consumption at 24 hours and APGAR scores <7 at 1 min was not significantly different. This meta-analysis shows that higher dosage (>100-250) of spinal morphine compared with lower dose (50-100) will prolong time to first analgesic request by 4.5hrs but at the cost of increased chance of side effects (pruritis and PONV).
Summarised by: Brenton Sanderson