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LETTER TO THE EDITOR

Etomidate, Nitric Oxide, and Cerebral Vasospasm

Division of Neuroanesthesiology; Department of Anesthesiology; University of Michigan Medical School; Ann Arbor, MI 48109-0048; gmashour{at}umich.edu

To the Editor:

In a recent case report describing accidental intracerebroventricular injection of etomidate and rocuronium in a patient with subarachnoid hemorrhage and cerebral vasospasm,1 Howell et al. discuss the possible deleterious effects of the drug delivery error on brain parenchyma, but do not address the potential effects of etomidate on the cerebral vasculature. Unlike propofol and sodium thiopental, which decrease cerebral blood flow by decreasing cerebral metabolism, etomidate has a direct effect as a cerebral vasoconstrictor.2 As a carboxylated imidazole, this effect may be mediated by inhibiting nitric oxide synthase.3 In the present case, propylene glycol (a vehicle for etomidate) could have also stimulated subarachnoid red cell lysis that resulted in hemoglobin scavenging of nitric oxide.3 Since nitric oxide is known to play an important role in cerebral vasospasm,4 it is conceivable that intracerebroventricular etomidate could have exacerbated the patient's preexisting vasospasm resulting in further neurologic deterioration. The use of etomidate in patients with cerebral vasospasm is a matter for further discussion.

REFERENCES

1. Howell S, Driver RP. Unintentional intracerebroventricular administration of etomidate and rocuronium. Anesth Analg 2008;106:520–2[Abstract/Free Full Text]
2. Milde LN, Milde JH, Michenfelder JD. Cerebral functional, metabolic, and hemodynamic effects of etomidate in dogs. Anesthesiology 1985;63:371–7[Web of Science][Medline]
3. Drummond JC, Cole DJ, Patel PM. Etomidate, vasospasm, and transfusion. J Neurosurg 2005;102:583–4[Web of Science][Medline]
4. Pluta RM, Thompson BG, Dawson TM, Snyder SH, Boock RJ, Oldfield EH. Loss of nitric oxide synthase immunoreactivity in cerebral vasospasm. J Neurosurg 1996;84: 648–54[Web of Science][Medline]

This article has been cited by other articles:

				S. M. Howell and R. P. Driver Etomidate, Nitric Oxide, and Cerebral Vasospasm Anesth. Analg., July 1, 2008; 107(1): 343 - 344. [Full Text] [PDF]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Mashour, G. A. Search for Related Content PubMed PubMed Citation Articles by Mashour, G. A.