14/09/2025
Very detailed and concise explanation of the Triad during Spinal coning
Important so you understand what you’re looking at
Elements of focus
Monroe Kellie Hypothesis
Increased intracranial pressure after cerebral auto regulation has been exhausted causes direct effect on Medulla….the primal cerebral functions of heart rate and respiratory rate.
Cardiac response of widening blood pressures (systolic rise with diastolic drop) - NEecessary cerebral perfusion pressure of 60 at least (equation is MAP - ICP = CPP)
Bradycardia due to systolic rise and or pressure on medulla or both. Remember if you are tachycardia with good ventricular stroke volume, your BP will rise, thus why some BP meds work by dropping heart rate, if that’s the source.
Finally, the altered breathing called Cheyne Stokes breathing. Deep irregular and infrequent breaths before coning of brain tissue through the Foramen Magnum, where spinal cord begins…… this triad in a remote area setting is the most challenging and mostly fatal event.
Mechanisms that cause this clinical crisis range from blunt force head injuries, to end stage liver failure, to sepsis, amongst other possible triggers.
For more detail on management of this often fatal scenario, look into the use of sedation and inotropic support used to flatten out cerebral activity , use of diuretic mannitol and manipulation of MAP to facilitate higher BP to counter the resistance from high ICPs.
