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Brain death (BD) diagnosis is the clinical assessment of the irreversible loss of function of the entire brain, including the brainstem. Transcranial Doppler (TCD) examination is used in several countries as a confirmatory test to assess cerebral circulatory arrest (CCA). A total of 1,400 TCD examinations were performed in 623 patients (pts) admitted to intensive care units (ICUs) of our hospital during the last 6 years. Oscillating flow, systolic spikes and the absence of any TCD signal were considered as diagnostic patterns of irreversible CCA. TCD patterns of CCA were detected in 56 pts. In 25 pts, deeply sedated with barbiturate therapy, TCD was employed as confirmatory test for BD diagnosis and 14 of them could become organ and/or tissue donors. TCD is a safe and inexpensive tool that can be performed at the bedside, and it allows to shorten the diagnostic process of BD, which is the prerequisite for organ donation.

Introduction. Cerebral blood flow has been well studied in patients with panic disorder, but only few studies analyzed the mechanisms underlying the onset of a panic attack. The aim of the present study was to monitor the cerebral hemodynamics modifications during a panic attack. Materials and Methods. 10 panic disorder patients with recent onset, fully drug naïve, were compared to 13 patients with panic disorder with a previous history of treatment and to 14 controls. A continuous bilateral monitoring of mean flow velocities in right and left middle cerebral arteries was performed by transcranial Doppler. Clomipramine was chosen as challenge. Results. Eight out of 10 patients drug naïve and 6 control subjects out of 13 had a full blown panic attack during the test, whereas none of the patients with a history of treatment panicked. The occurrence of a panic attack was accompanied by a rapid decrease of flow velocities in both right and left middle cerebral arteries. Discussion. The bilateral acute decrease of mean flow velocity during a panic attack suggests the vasoconstriction of the microcirculation of deep brain structures perfused by middle cerebral arteries and involved in the so-called “fear circuitry,” thus suggesting that cerebral homeostatic dysfunctions seem to have a key role in the onset of a panic attack.

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