Impact of Sub-Anesthetic Dose of Ketamine on Post Spinal Hypotension in Cesarean Delivery

Spinal anesthesia is the commonest technique used in Cesarean Section (CS) and most frequently associated with maternal hypotension, for which a lot of techniques have been described to prevent but an effective method is yet to be found.

The aim was to study the effect of using a sub-anesthetic dose of ketamine to prevent post-spinal hypotension in CS delivery.

This double-blinded randomized controlled study was conducted on 80 participating parturients who were ASA І, П term pregnant. All the parturients received spinal anesthesia. The parturients were then randomly divided into two equal groups (n= 40 in each); ketamine group received a sub-anesthetic dose of ketamine of 0.5 mg/kg IV bolus in 3 ml saline and control group received the same volume of normal saline IV bolus. Heart Rate (HR) and Mean Arterial blood Pressure (MAP) were recorded at baseline (5 minutes prior to the intrathecal injection), at 5, 10, 15 and 20 minutes after the injection and then every 15 minutes till the end of the operation. Incidences of hypotension and severe hypotension were recorded. The total dose of ephedrine was recorded. Ramsay sedation score was recorded at baseline then 5, 10, 15, 30, 45 minutes after injection and then at the end of the operation.

Compared to the control group, sedation score was significantly higher among ketamine group at 5, 10 and 15 minutes. MAP and HR were significantly higher among ketamine group at 5, 10, 15, and 20 minutes. Total ephedrine dose was significantly lower among the ketamine group. Mild hypotension and severe hypotension were significantly less frequent among the ketamine group, as all the patients in the control group had an attack of mild hypotension and 55% of this group had an attack of severe hypotension. No significant difference between both the groups regarding diplopia, nystagmus, hallucination, nausea and vomiting.

It is concluded that ketamine in a sub-anesthetic dose is an effective agent that can be used in preventing post-spinal hypotension in parturients undergoing CS delivery.