مرکز منطقه ای اطلاع رساني علوم و فناوري - The Effect of Intravenous Morphine on the Level of Spinal Anesthesia with Lidocaine

Author/Authors :

Masoudifar, Mehrdad isfahan university of medical sciences - Department of Anesthesiology and Critical Care, ايران , Aghadavoudi, Omid isfahan university of medical sciences - Anesthesiology and Critical Care Research Center, ايران , Rezvani, Mehran isfahan university of medical sciences - Department of Anesthesiology and Critical Care, ايران , Mashayekhi, Neda isfahan university of medical sciences - Faculty of Medicine, ايران

Abstract :

One of the major concerns in spinal anesthesia with lidocaine is its short duration of action. Enhancement is necessary in some situa-tions during surgery, because surgeons encounter with unexpected events and need more time. Therefore there is a need to increase anesthesia duration in these situations. Many studies investigated various additiveswith different administration routes to enhance spread and duration ofspinal block with lidocaine. Because we only have morphine sulfate in our clinics and the sulfate compounds are neurotoxic, we cannot prescribe it by intrathecal route; for this reason we investigated effects of intravenous morphine on the spinal anesthesia with lidocaine. Methods: This double blinded randomized clinical trial study was performed on 36 patients who were allocated to two groups. All patients underwent spinal anesthesia with lidocaine by the same method. Patients in the case group received morphine plus midazolam intravenously as the additive medication and in the control group received normal saline plus midazolam. Duration, spinal block level, recovery time, sedation score and adverse effects were compared between the two groups. Results: This study showed that although intravenous morphinecan provide better safe sedation (p-value 0.01), it has no effect on the level (p-value: 0.42) and duration of spinal block (p-value: 0.26). Although heart rate and blood pressure had significant decrease in the case group (p-value 0.01 and 0.05 respectively) but the need for administration of ephedrine was completely similar in both groups. Conclusion: Although some studies had proved the efficacy of systemic use of other opioids including fentanyl and sufentanil, morphine had no effect on the level and duration of spinal block. It can be due to differences in the chemical structures of these sub- stances. However, intravenous morphine as an additive to spinal anesthesia with lidocaine can provide acceptable sedation with no major side effects.