Impact of Intravenous Dexamethasone on the Duration of Motor and Sensory Block Following Spinal Anesthesia With Chloroprocaine

Spinal anesthesia is commonly used for lower body surgery. The injection of local anesthetics in the lumbar intrathecal space allows the desensitization of the lower body by blocking sensory and motor nerve roots. In return, spinal anesthesia causes a sympathetic block which is associated with deleterious hemodynamic effects such as hypotension.

Isobaric chloroprocaine is a local anesthetic increasingly used for spinal anesthesia to reduce the duration of sensory and motor blocks compared to bupivacaine, allowing for faster postoperative recovery. However, certain medications used during surgery may possibly influence the duration of spinal anesthesia. Among these is dexamethasone, a drug belonging to the corticosteroid family. Dexamethasone is a well-known and commonly used medication in anesthesia to prevent postoperative nausea and vomiting. It is also used by anesthesiologists to reduce pain in the context of fast functional recovery after surgery. The safety of single-dose intravenous dexamethasone is therefore established in the context of anesthesia for several types of surgery.

Medical literature demonstrates that dexamethasone can prolong the effect of certain local anesthetics when administered intravenously or perineurally (near the nerves), and sometimes has no effect on the duration of local anesthetics administered for spinal anesthesia. Currently, no information is available in the literature on the effect of intravenous dexamethasone on the duration of a spinal anesthesia with isobaric chloroprocaine.

This study aims to compare the effect of a single dose of 8 mg of intravenous dexamethasone versus placebo on the duration of sensory and motor block after spinal anesthesia with chloroprocaine.

Inclusion criteria

• Age between 18 and 90 years old
• ASA status I to III inclusively
• Planned lower body surgery under spinal anesthesia with chloroprocaine
• Signed informed consent form

Exclusion criteria

• Contraindication to spinal anesthesia: infection at the puncture site, congenital or acquired coagulopathy
• Preexisting neuropathy or nerve block that could interfere with study assessments
• Allergy or hypersensitivity to local anesthetics, dexamethasone, or other medications used in the study
• Preoperative use of corticosteroids
• Patient refusal
• Inability to consent
• Language barrier, psychiatric, physical, or mental condition making sensory and motor blocks assessment impossible despite prior instruction
• Administration of any intrathecal adjuvant (fentanyl, morphine, clonidine, dexmedetomidine, epinephrine, or others) along with chloroprocaine
• Perioperative intravenous dexmedetomidine administration
• Conversion to general anesthesia
• Impossible post-anesthesia care unit assessment: patient still intubated / transfer to intensive care unit, research team constraints, or other reasons
• Assessment in the recovery room impossible: medical condition (shock, delirium, major agitation, altered state of consciousness, or other), transfer to the intensive care unit, research team constraints, or other