Comparison of ketamine to non-ketamine induction in patients with ruptured aortic aneurysm

Ketamine is thought to be the induction agent of choice in hypovolaemic states since it retains or restores blood pressure in hypovolaemic situations. This effect on blood pressure is due to the ability of ketamine to augment sympathetic activity. To our knowledge, the effect of ketamine on sympathetic activity and/or blood pressure in the hypovolaemic patient has not been investigated. Animal studies have shown a negative inotropic effect of ketamine. In the hypovolaemic animal blood pressure falls in some cases and blood flow is redistributed away from vital organs. These effects may persist for long periods. The nature and urgency of the hypovolaemic state may preclude informed consent, randomization and blinding. We therefore carried out the following retrospective comparison of the effects of ketamine and non-ketamine induction of patients with ruptured aortic aneurysm as a pilot study.