LETTERS TO THE EDITOR: Letters & Announcements
To the Editor:
While hypotension after acute brain injury is dangerous, we remain concerned that the use of vasopressin, as described by Yeh et al. (1), may contribute to cerebral ischemia.
Yeh et al. suggest that vasopressin may have vasodilatory actions in the brain. However, experimental studies are equivocal (2), and there are no data from human studies. While some patients with acute brain injury may need “second line” vasopressors, the possibility of cerebral vasoconstriction or reduction in blood flow remains a concern. Failure to exclude such side effects may result in potentiation of the secondary brain injury that we are trying to avoid. These observations are underlined by our recent experience with terlipressin, a vascular specific analog of vasopressin, in patients with acute brain injury and norepinephrine resistant hypotension. While terlipressin improved cerebral perfusion pressure and reduced norepinephrine requirements, it had no effect on intracranial pressure or middle cerebral artery flow velocities, measured using transcranial Doppler ultrasound. Until the safety of such agents is supported by formal clinical studies, we believe that their use in patients with acute brain injury should always be accompanied by monitors of cerebral blood flow and cerebrovascular adequacy such as transcranial Doppler ultrasound and jugular bulb oximetry.
Peter Bradley, MD
Magdalena Hiler, MD
David Menon, MD
1. Yeh C-C, Wu C-T, Lu C-H et al. Early use of small-dose vasopressin for unstable hemodynamics in an acute brain injury patient refractory to catecholamine treatment: a case report. Anesth Analg 2003; 97: 577–9.
2. Faraci FM. Effects of endothelin and vasopressin on cerebral blood vessels. Am J Physiol Heart Circ Physiol 1989; 257: 799–803.