Arterial hypoxemia caused by intravenous ketamine

Area of Science:

• Anesthesiology
• Pharmacology
• Respiratory Physiology

Background:

• Ketamine is an anesthetic agent used for various procedures.
• Spontaneously breathing patients with unassisted airways may be vulnerable to respiratory depression during anesthesia.

Purpose of the Study:

• To investigate the effect of intravenous ketamine on arterial oxygen tension (Pao2) in spontaneously breathing patients.
• To determine if pre-administration of diazepam modifies ketamine's impact on Pao2.

Main Methods:

• A prospective study involving two groups of spontaneously breathing patients.
• Group 1 received ketamine (2 mg/kg IV).
• Group 2 received diazepam (0.2 mg/kg IV) followed by ketamine (2 mg/kg IV).
• Arterial oxygen tension (Pao2) was measured before and after drug administration.

Main Results:

• Ketamine administration resulted in a significant reduction in Pao2 in all patients.
• Pre-treatment with diazepam did not significantly alter the Pao2 reduction caused by ketamine.
• Some patients experienced critically low Pao2 levels (≤40 torr) post-ketamine.

Conclusions:

• Intravenous ketamine administration can cause significant hypoxemia in spontaneously breathing patients.
• The combination of ketamine and diazepam does not mitigate this risk.
• Supplemental oxygen and ventilatory assistance are recommended during IV ketamine anesthesia for spontaneously breathing patients.