A systematic review of cannabidiol dosing in clinical populations.

AIMS: Cannabidiol (CBD) is a cannabis-derived medicinal product with potential application in a wide-variety of contexts; however, its effective dose in different disease states remains unclear. This review aimed to investigate what doses have been applied in clinical populations, in order to understand the active range of CBD in a variety of medical contexts. METHODS: Publications involving administration of CBD alone were collected by searching PubMed, EMBASE and ClinicalTrials.gov. RESULTS: A total of 1038 articles were retrieved, of which 35 studies met inclusion criteria covering 13 medical contexts. Twenty-three studies reported a significant improvement in primary outcomes (e.g. psychotic symptoms, anxiety, seizures), with doses ranging between <1 and 50 mg/kg/d. Plasma concentrations were not provided in any publication. CBD was reported as well tolerated and epilepsy was the most frequently studied medical condition, with all 11 studies demonstrating positive effects of CBD on reducing seizure frequency or severity (average 15 mg/kg/d within randomised controlled trials). There was no signal of positive activity of CBD in small randomised controlled trials (range n = 6-62) assessing diabetes, Crohn's disease, ocular hypertension, fatty liver disease or chronic pain. However, low doses (average 2.4 mg/kg/d) were used in these studies. CONCLUSION: This review highlights that CBD has a potential wide range of activity in several pathologies. Pharmacokinetic studies as well as conclusive phase III trials to elucidate effective plasma concentrations within medical contexts are severely lacking and highly encouraged.

Continuous monitoring of jugular bulb oxyhaemoglobin saturation using the Edslab dual lumen oximetry catheter during and after cardiac surgery.

Fibreoptic jugular bulb oximetry has been validated for use in the care of severely head-injured patients. We compared bench and fibreoptic methods of measuring jugular bulb oxyhaemoglobin saturation (SjO2) in 33 patients undergoing cardiac surgery both during cardiopulmonary bypass (CPB) and in the early postoperative period. After insertion of a fibreoptic reflectance oximetry catheter into the jugular bulb, it was calibrated against a bench oximeter. Comparisons were made while on CPB (n = 60) and in the postoperative period for up to 18 h (n = 215). There was negligible bias throughout. There were wide limits of agreements (mean difference +/- 2SD) between the two methods during operation (-20.29% to 18.05%), whereas after operation the limits of agreement were far narrower (-6.39% and 7.45%). Measurement of SjO2 by the fibreoptic method compared poorly with bench oximetry during CPB but there was good agreement between the two methods in the early postoperative period.

Aerobic, anaerobic and combination estimates of cerebral hypoperfusion during and after cardiac surgery.

We studied 15 patients undergoing cardiac surgery involving hypothermic cardiopulmonary bypass (CPB). Cerebral arteriovenous difference in oxygen content (AVDO2) was significantly less during CPB and for up to 18 h after operation compared with pre-CPB values (P < 0.05). There were no significant changes in mean jugular bulb oxyhaemoglobin saturation (SjvO2), cerebral arteriovenous difference in lactate content or lactate-oxygen index (LOI). SjVO2 and arterial carbon dioxide tension (PaCO2) (P = 0.005) were positively correlated as were AVDO2 and haemoglobin concentration (P = 0.012). AVDO2 and PaCO2 (P = 0.007) were negatively correlated as were LOI and arterial oxyhaemoglobin saturation (P = 0.037). There were no significant correlations between mean arterial pressure and any of the variables. SjVO2 and AVDO2 may require correction for changes in PaCO2 and haemoglobin concentration before relating these variables to cerebral outcome.