The effect of ketamine on intracranial pressure during haemorrhagic shock under the conditions of both spontaneous breathing and controlled ventilation

Abstract

Seventeen piglets of both sexes, seven with O2/air-buprenorphine anaesthesia and controlled ventilation, and ten unanaesthetized animals with normal, spontaneous respiration, were used for the study. The intracranial pressure of both groups of animals was raised by insufflation of an epidural balloon and the arterial blood pressure was reduced to approximately 70% of the original value by controlled haemorrhage. 0.5 mg/kg body weight of ketamine was given intravenously, followed by a further dose of 2.0 mg/kg body weight of ketamine five minutes later. Both ketamine doses led to a significant rise in the intracranial pressure of those animals breathing spontaneously (31.8 mm Hg to 39.1 mm Hg). In contrast, the ventilated animals showed a significant reduction in intracranial pressure. No changes in arterial PCO2 were observed in this group, while those piglets breathing spontaneously had dangerous PCO2 rises. At both ketamine doses a significant correlation could be found between the PCO2 and the intracranial pressure.

Effects of Fentanyl and S(+)-ketamine on Cerebral Hemodynamics, Gastrointestinal Motility, and Need of Vasopressors in Patients With Intracranial Pathologies

“…20,21 As demonstrated in recent studies, ketamine does not lead to an elevation of ICP. 6,13,22,23 The combination of ketamine and midazolam was comparable with the combined application of sufentanil and midazolam in maintaining ICP and CPP in patients with severe head injury. 6 Furthermore, an increase in ketamine plasma concentration was not associated with adverse effects on cerebral hemodynamics 7 and the sympathomimetic effects of ketamine may in fact be beneficial for maintaining circulatory stability.…”

Ketamine as an Anesthetic for Patients with Acute Brain Injury: A Systematic Review

“…All studies used ventilators. No patients were on spontaneous breathing which, in an animal model, has shown to increase intracranial pressure during ketamine sedation [27]. We thus recommend hesitation in relation to conclusions regarding potential correlations between ketamine administration and changes in ICP levels.…”

Total Intravenous Anesthesia Including Ketamine versus Volatile Gas Anesthesia for Combat-related Operative Traumatic Brain Injury

“…When ventilation is controlled, how-ever, ketamine, especially when combined with propofol or midazolam, tends to decrease ICP and CMRO 2 and not increase them. 19,41 Positron emission tomography scanning after ketamine administration demonstrates little change in CMRO 2 and only marginal increases in cerebral blood volume. 20 Regional oxygen extraction fraction decreases with ketamine alone.…”