Dexamethasone Intravenous Versus Intrathecal in Spinal Anesthesia

1. Pre-operative settings: Detailed preoperative examination and preoperative investigations (complete blood picture, Bleeding Time, prothrombin time and partial thromboplastin time) were performed. Age and weight were recorded. The patient was fasting for 8 hours preoperatively. In the preanesthetic room, 18-gauge intravenous cannula was sited. Patients was preloaded with 5 mL/kg of lactated Ringer's solution over 20 minutes. The visual analogue scale (VAS) for pain was explained to the patients
2. Intra-operative Settings Inside the operating room, mean arterial blood pressure (MAP), heart rate (HR), electrocardiography (ECG) and peripheral oxygen saturation (SpO2) were obtained using standard non-invasive monitors and base line values were recorded.

The spinal technique was performed under complete aseptic condition with the patient in sitting position at the L3- L4 or L4 -L5 intervertebral space with 25-gauge spinal needle through midline approach. The spinal drugs were administered over 30 second according to each group.

Groups:

The eligible patients were enrolled in this double blinded study and randomly allocated to one of three groups by computer generated random number lists. The allocation was concealed using closed opaque envelopes. The solution for intrathecal injection was prepared by an anesthesiologist who did not have a further role in the study.

Control group (n= 22): Participants were received normal saline 2 mL intravenously with intrathecal injection of heavy bupivacaine 0.5% 2 mL (10mg) plus 1 mL of 0.9% saline, overall 3 ml volume intrathecally (Pyasetska, 2020).

IT group (n= 22): Participants were received normal saline 2 mL intravenously with intrathecal injection of heavy bupivacaine 0.5% 2 mL (10mg) plus 0.5 mL (2mg) dexamethasone diluted in 0.5 ml of 0.9% saline, overall 3 ml volume intrathecally. The dose of 2mg of dexamethasone was demonstrated by Amer (2018) to be the least effective intrathecal dose.

IV group (n= 22): Participants were received dexamethasone 2 mL (8mg) intravenously with intrathecal injection of heavy bupivacaine 0.5% 2 mL plus 1 mL of 0.9% saline (Pyasetska, 2020).

After completing the intrathecal injection, the patient was immediately placed in the supine position IV Ringer's solution 10 ml/kg/hour was administered throughout the surgery. Oxygen was administered through a nasal cannula in a rate of 2 L/min.

Measurements:

Sensory block was assessed according to loss of sensation using cold alcohol swab every two minutes after completing the spinal injection. Time to reach the sensory level of T10 was recorded to determine the effect of the drug on the onset of the spinal anesthesia.

Spinal anesthesia was considered adequate to undergo surgery if the sensory level reaches a T4 level, otherwise the patients were excluded from the study, recorded as "excluded due to low level" and replaced by another patient to achieve the required sample size.

The highest level reached within 30 min, and its time, were recorded. Hemodynamic parameters (heart rate and mean arterial pressure) and SpO2 were measured and recorded just after performing spinal anesthesia, and at 10 min interval till the end of the surgery.

Bradycardia, defined as a heart rate decrease more than 20% of the baseline (preoperative) value, will be treated by atropine 0.6 mg IV.

Hypotension, defined as a decrease in MAP more than 20% of the baseline value, will be treated by IV ephedrine 3 mg IV increments.

Episodes of bradycardia and hypotension and doses of administered drugs for treatment were recorded.

A decrease of SpO2 below 92% was treated by increasing the oxygen flow rate and management of the airway if necessary. The occurrence of this event was recorded.

Occurrence of side effects as nausea, vomiting, itching or shivering were recorded.

Time to two-segment regression of the sensory block from the highest level. The level was assessed every 10 minutes, after reaching the highest sensory level, by loss of sensation to cold alcohol swab. This time was considered as the duration of the sensory block