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The effects of three graded doses of meperidine for spinal anesthesia in African men
Unlabelled:
The intrathecal injection of 0.7-1 mg/kg meperidine provides spinal anesthesia of only short duration. In this study, we investigated the effects of three different doses of meperidine for spinal anesthesia on the duration and level of sensory block and the incidence of side effects. Forty-five African men were randomly allocated to receive one of three doses of intrathecal meperidine: Group A = 1.2 mg/kg, Group B = 1.5 mg/kg, and Group C = 1.8 mg/kg. The duration of sensory block was significantly longer after 1.5 mg/kg compared with 1.2 mg/kg meperidine (112 +/- 19 vs 79 +/- 27 min; P = 0.001). Increasing the dose to 1.8 mg/kg did not further increase the duration of block. The level and the onset of the block were not affected by the dose. Common side effects were fatigue (27%), pruritus (20%), and nausea (7%). Seven patients had respiratory depression and seven had a decrease of systolic arterial blood pressure (SAP) >30% from baseline. There was no difference in the incidence of any side effect among groups. Respiratory depression and decreases in SAP were observed 5-50 min after meperidine injection. Twenty-two patients had no pain after the sensory block had terminated. We conclude that increasing the dose of meperidine from 1.2 to 1.5 mg/kg increased the duration, but not the level, of sensory block without an increase in side effects.
Implications:
Intrathecal meperidine 1 mg/kg provides surgical anesthesia for only 40-90 min. We investigated the effects of three larger doses of meperidine in 45 African men. The 1.5 and 1.8 mg/kg doses provide a longer duration of anesthesia compared with 1.2 mg/kg. Nausea, pruritus, and respiratory depression were common in all dose groups. We conclude that increasing the dose of meperidine from 1.2 to 1.5 mg/kg increased the duration, but not the level, of sensory block without an increase in side effects.
Insights
Increasing intrathecal meperidine (spinal anesthesia) dosage to 1.5 mg/kg significantly extends block duration compared to 1.2 mg/kg, without increasing side effects. Higher doses did not further prolong anesthesia.
Area of Science:
- Anesthesiology
- Pharmacology
Background:
- Intrathecal meperidine at 0.7-1 mg/kg offers short-duration spinal anesthesia.
- Optimizing meperidine dosage is crucial for extending anesthesia duration.
Purpose of the Study:
- To evaluate the impact of three different intrathecal meperidine doses on sensory block duration, level, and side effects.
- To determine the optimal meperidine dosage for spinal anesthesia in African men.
Main Methods:
- Forty-five African men received intrathecal meperidine at 1.2, 1.5, or 1.8 mg/kg.
- Sensory block duration, level, onset, and side effects were monitored and compared across groups.
Main Results:
- A 1.5 mg/kg dose significantly increased sensory block duration (112 min) versus 1.2 mg/kg (79 min).
- Dose increases beyond 1.5 mg/kg did not further extend block duration.
- Block onset and level were unaffected by meperidine dose; common side effects included fatigue, pruritus, and nausea.
Conclusions:
- Increasing intrathecal meperidine from 1.2 to 1.5 mg/kg prolongs sensory block duration without increasing adverse events.
- 1.5 mg/kg appears to be a more effective dose for achieving longer-lasting spinal anesthesia with meperidine.