The 1970s were a dark time for ketamine use in patients with intracranial pathology. In patients with non-traumatic lesions, ketamine was suggested to increase intracranial pressure (ICP) using various markers as end-points to suggest this (see references below). Although this concern still remains with traditionalists, we have since seen multiple studies debunking this myth.

Now there is finally a meta-analysis supporting the suggestion that ketamine certainly does not seem to increase ICP. A systematic review of RCTs comparing the effects of ketamine vs opioids on 24-hour ICPs found that ketamine produced similar changes to ICP, MAP and CPP when compared to opioids. Surprised? Me neither.

Although this paper has some obvious flaws (small numbers, only 5 trials included, different choice of opioids, trials took place over 17 years, boluses vs infusions not addressed), this is one of the first meta-analysis to look at this surprisingly commonly misunderstood practice.

It is probably time for those Anaesthetics/Emergency Medicine/Pharmacology text books to be rewritten. And it is probably time to stop discussing whether ketamine can be used as an induction agent in TBI.

1. Wang X, Ding X, Tong Y, Zong J, Zhao X, Ren H, Li Q. Ketamine does not increase intracranial pressure compared with opioids: meta-analysis of randomized controlled trials. J Anesth. 2014 May 24.

2. Gardner AE, Olson BE, Lichtiger M. Cerebrospinal fluid pressure during dissociative anesthesia with ketamine. Anesthesiology 1971;35:226-8.

3. Wyte SR, Shapiro HM, Turner P, et al. Ketamine induced intracranial hypertension. Anesthesiology 1972;36:174-6.

4. Gibbs JM. The effect of intravenous ketamine on cerebrospinal fluid pressure. Br J Anaesth 1972;44:1298-302.

5. Gardner AE, Dannemiller FJ, Dean D. Intracranial cerebrospinal fluid pressure in man during ketamine anesthesia. Anesth Analg 1972;51:741-5.

6. Shaprio HM, Wyte SR, Harris AB. Ketamine anesthesia in patients with intracranial pathology. Br J Anaesth 1972;44:1200-4.

7. List WF, Crumrine RS, Cascorbi HF, et al. Increased cerebrospinal fluid pressure after ketamine. Anesthesiology 1972; 36:98-9.