Nebulized Versus Intravenous Ketamine as Prophylaxis Against Spinal Anesthesia-induced Shivering and Hemodynamic Changes: A Placebo-controlled Prospective Study

Shivering is an involuntary muscle activity, often triggered by hypothermia, that can occur after anesthesia. This is known as postanesthetic shivering (PAS) and is a common issue that increases oxygen demand, raises the risk of low oxygen levels, and can lead to complications after surgery.

Spinal anesthesia (SA) is a popular choice due to its quick action and effective numbing. However, it's frequently linked to shivering during and after the procedure.

To combat PAS, various methods have been used. Non-pharmacological approaches like insulation, continuous warming, and temperature management have been shown to reduce low body temperature during surgery and decrease shivering and complications afterward, aiding recovery.

Pharmacologically, certain medications can help. Intrathecal meperidine or intravenous (IV) ketamine are effective in preventing PAS. Intrathecal midazolam can also reduce shivering, unlike fentanyl. Additionally, IV ketamine infusion can lower the incidence of low blood pressure and shivering in patients receiving SA. Low-dose ketamine combined with dexmedetomidine, or dexmedetomidine alone, have also shown similar effectiveness in reducing shivering and postoperative nausea and vomiting during SA.