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.

• Intravenous Dexamethasone (Drug), also known as Decadron: Administration of a single-dose of intravenous dexamethasone 8 mg during spinal anesthesia with chloprocaine
• Normal Saline (Drug), also known as Placebo: Administration of a single-dose of Normal saline during spinal anesthesia with chloprocaine

Primary outcomes

• Regression of sensory block by 2 dermatomes [At regression of spinal anesthesia by 2 dermatomes, approximately 60 minutes after surgery]: Loss of pinprick sensation by Von Frey filaments from the injection of chloroprocaine for spinal anesthesia until regression of the sensory block by two dermatomes from the peak sensory level

Secondary outcomes

• Duration of motor block [At 5,10,15 and 20 minutes following spinal anesthesia, then every 10 minutes until complete recovery, approximately 90 minutes after surgery]: Using the Bromage scale from the time of injection of chloroprocaine for spinal anesthesia until complete recovery of motor block
• Time until the first observable regression of the motor block [At 5,10,15 and 20 minutes following spinal anesthesia, then every 10 minutes until complete recovery, approximately 90 minutes after surgery]: Time between the local anesthesic injection and the first measurable regression of the motor block measured using the Bromage scale.
• Onset of sensory block [Up to 30 minutes following spinal anesthesia]: Time from injection of chloroprocaine for spinal anesthesia to reduction of sensitivity using loss of pinprick sensation
• Onset of motor block [Up to 30 minutes following spinal anesthesia]: Time from injection of chloroprocaine for spinal anesthesia to reduction of lower limbs movement using the Bromage scale
• Quality of motor block [Up to 30 minutes following spinal anesthesia]: Maximal Bromage score The Bromage scale is a standardized tool used in neuraxial anesthesia to quantify motor block intensity in the lower extremities. It assesses a patient's ability to move their legs and feet. A scale of 0 to 3 is used: 0 - Full movement, 1- Partial block, 2 - Nearly complete block and 3 - Complete block. The maximal Bromage score reflects the deepest level of lower-limb motor block, with higher scores indicating stronger motor impairment and therefore a denser motor block.
• Opioid consumption [At recovery room discharge, approximately one hour after the end of surgery]: Total dose of opioids
• Antiemetic consumption [At recovery room discharge, approximately one hour after the end of surgery]: Total dose of antiemetics
• Incidence of hypotension [From injection of chloroprocaine for spinal anesthesia to recovery room discharge, approximately one hour after the end of the surgery]: Systolic blood pressure lower than 90 mm Hg
• Incidence of bradycardia [From injection of chloroprocaine for spinal anesthesia to recovery room discharge, approximately one hour after the end of the surgery]: Heart rate slower than 50 beats per minute
• Incidence of nausea [From injection of chloroprocaine for spinal anesthesia to recovery room discharge, approximately one hour after the end of the surgery]: Any episode of nausea reported by the patient or nursing team
• Incidence of vomiting [From injection of chloroprocaine for spinal anesthesia to recovery room discharge, approximately one hour after the end of the surgery]: Any episode of retching or vomiting reported by the patient or nursing team
• Incidence of itching [From injection of chloroprocaine for spinal anesthesia to recovery room discharge, approximately one hour after the end of the surgery]: Any episode of itching reported by the patient or nursing team
• Incidence of urinary retention [From injection of chloroprocaine for spinal anesthesia to recovery room discharge, approximately one hour after the end of the surgery]: Any episode of urinary retention reported by the patient or nursing team
• Incidence of shivering [From injection of chloroprocaine for spinal anesthesia to recovery room discharge, approximately one hour after the end of the surgery]: Any episode of shivering reported by the patient or nursing team
• Incidence of headache [From injection of chloroprocaine for spinal anesthesia to recovery room discharge, approximately one hour after the end of the surgery]: Any episode of headache reported by the patient or nursing team
• Quality of postoperative recovery [At 24 hours after the surgery]: QoR15 is a valid questionnaire to measure the quality of recovery after surgery and anaesthesia, which includes 15 questions. Each of the 15 items are scored by the patient from 0 (worst score) to 10 (optimal score), giving a lowest possible score of 0 (worst outcome), and a highest possible score of 150 (optimal outcome).
• Intensity of nausea/vomiting [At 24 hours after surgery]: Pre-established analysis of nausea/vomiting intensity at 24 hours based on the QoR-15 question. QoR15 is a valid questionnaire to measure the quality of recovery after surgery and anaesthesia, which includes 15 questions. Each of the 15 items are scored by the patient from 0 (worst score) to 10 (optimal score).
• Pain intensity [At 24 hours after surgery]: Pre-established analysis of pain intensity at 24 hours based on the QoR-15. QoR15 is a valid questionnaire to measure the quality of recovery after surgery and anaesthesia, which includes 15 questions. Each of the 15 items are scored by the patient from 0 (worst score) to 10 (optimal score).
• Quality of sleep [At 24 hours after surgery]: Pre-established analysis of sleep quality at 24 hours based on the QoR-15. QoR15 is a valid questionnaire to measure the quality of recovery after surgery and anaesthesia, which includes 15 questions. Each of the 15 items are scored by the patient from 0 (worst score) to 10 (optimal score).
• Surgeon's satisfaction towards spinal anesthesia [At the end of surgery, on the day of randomization]: Unsatisfied or satisfied

Sex: All, ages: 18 Years to 90 Years

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

• Stephan Williams, MD, PhD, Principal investigator, Santé Québec - CHUM