1/3. Anaesthetic management of a pregnant patient in a persistent vegetative state.pregnancy in a patient in a persistent vegetative state presents challenging therapeutic questions about the level of supportive management required, the assessment of fetal well-being, the timing and mode of delivery and the anaesthetic management of labour and delivery. We report the case of a 29-yr-old woman who had a favourable fetal outcome despite suffering hypoxic brain damage after a suicide attempt by a drug overdose. She was managed until the onset of labour on an intensive care unit and had a spontaneous vaginal delivery assisted by epidural anaesthesia.- - - - - - - - - - ranking = 1keywords = anaesthesia (Clic here for more details about this article) |
2/3. Bispectral index-guided management of anaesthesia in permanent vegetative state.A patient in a permanent vegetative state required general anaesthesia for dental surgery. Because of the uncertainties involved in the appropriate monitoring and assessment of the conscious level of patients in a permanent vegetative state, it was decided to use the bispectral index to help guide the anaesthetic depth during surgery. We found that the bispectral index profile during anaesthesia and surgery was similar to that of a normal subject. The findings raise the possibility that patients in permanent vegetative states might sense noxious stimuli at a cortical level.- - - - - - - - - - ranking = 6keywords = anaesthesia (Clic here for more details about this article) |
3/3. Coordinated expression in chronically unconscious persons.The clinically described 'persistent vegetative state' (PVS), consists of wakefulness unaccompanied by any evidence of the subject's awareness of self or environment. Past studies from our own and other laboratories have used positron emission tomography (PET) to study brain metabolism in approximately 20 such patients during wakeful periods. All those efforts identified global cerebral glucose metabolism at or below levels encountered during deep barbiturate anaesthesia. Nevertheless, the clinical literature includes rare reports of relatively isolated cognitive functions expressed by PVS patients late in their course. The observation raises the question of whether such activity reflects awareness or unconscious automatic behaviour. We employed magnetometry (MEG), PET scanning, MR imaging and 24-hour EEG recordings to evaluate three patients clinically vegetative between six months and 20 years after onset. Neither meticulous clinical examinations nor 24-hour EEG and video monitoring provided any hint of cognitive interaction in any subject. Nevertheless, patient 1 uttered single words once every 48 hours or more; patient 2 frequently expressed coordinated, non-purposeful, non-dystonic movements in arms and/or legs; and, patient 3 expressed strong emotional negativity without motor responses to noxious stimuli with occasional quieting in response to prosodic stimuli. All patients had whole-brain averaged global metabolism levels below 50% of normal. Patient 1, however, demonstrated preserved islands of increased metabolism in the posterior frontal and posterior temporal lobes, as well as MEG activations of Heschl's gyrus all located in the left hemisphere. In patient 2, selected increased metabolism was confined to the frontal poles and related subcortical structures. MRI in patient 3 demonstrated severe, bilateral post-traumatic cerebral atrophy. PET metabolism was diffusely reduced to 40% of normal but MEG evoked potentials indicated early and late sensory processing with abnormal later evoked components. The correlation of fragmentary behaviour with preserved metabolic and physiologic activity in cortical and subcortical regions known to support specific modular functions is novel. The finding demonstrates the capacity of severely damaged brains to partially express surviving modular functions without evidence of integrative processes that would be necessary to produce consciousness. We conclude that the mere expression of isolated neuropsychologic activity by isolated modules is insufficient to generate consciousness in overwhelmingly damaged brains.- - - - - - - - - - ranking = 1keywords = anaesthesia (Clic here for more details about this article) |