Intralipid Reverses Propofol‐Mediated Hypotension in Rats

Abstract

IntroductionPropofol is a commonly used anesthetic. Despite its favourable safety profile, propofol causes hypotension which can result in end‐organ hypoperfusion. Intralipid is a lipid emulsion that has been shown to reverse the vasodilatory effects of propofol in isolated vessels; however, whether these effects are recapitulated in vivo is not known. The objectives of this study were to determine if intralipid reverses the hypotensive and anesthetic effects of propofol in rats.MethodsUnder isoflurane anesthesia, male Sprague Dawley rats were instrumented with indwelling catheters for mean arterial pressure (MAP) assessments as well as subdural electrodes for cortical activity assessments by electroencephalography (EEG).ResultsPropofol (10 mg/kg IV) caused hypotension (55±2% drop in MAP, P<0.001) and intralipid (4mL/kg IV) caused greater reversal (80±9%) of blood pressures compared to saline (19±1%; P<0.001). Blockade of the autonomic nervous system with chlorisondamine (2.5 mg/kg IV) caused marked hypotension (56±3% lowering of MAP, P<0.001) which could be reversed with a constant infusion of phenylephrine (300 μg/kg/hr); under these conditions, propofol nevertheless caused hypotension (12±4% lowering of MAP) which was completely reversed by intralipid. Propofol‐induced cortical burst suppression was not affected by intralipid (2±3%), saline (‐4%) or 20% BSA (‐2±1%; P=0.27).ConclusionThese results demonstrate that intralipid reverses propofol‐mediated hypotension with minimal effects on its anesthetic profile. Intralipid could be particularly useful as a rescue against propofol in patients prone to hemodynamic instability such as the elderly.This work was funded by a grant from the University Hospital Foundation.