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Correspondence  |   January 2003
Bispectral Index and Mitochondrial Myopathies
Author Notes
  • Division of Anesthesia, St. Peter Hospital, Olympia, Washington.
Article Information
Correspondence
Correspondence   |   January 2003
Bispectral Index and Mitochondrial Myopathies
Anesthesiology 1 2003, Vol.98, 282. doi:0000542-200301000-00051
Anesthesiology 1 2003, Vol.98, 282. doi:0000542-200301000-00051
To the Editor:—
I am troubled that Morgan et al.  1 used the Bispectral Index (BIS) to measure anesthetic sensitivity in 16 patients with mitochondrial myopathy. There is no evidence (Medline search, June 5, 2002) that supports the use of the BIS as a valid measure in the abnormal brain. Patients with mitochondrial myopathy who have central nervous system dysfunction have abnormal electroencephalographic activity. 2–4 How can the BIS algorithm, based on the effects of hypnotic agents in presumably normal brains, 5 be considered valid in patients who suffer from seizures, encephalopathy, and stroke-like episodes?
Equally troubling is that the study was performed without informed parental consent. The authors state that this was not a study, and patients received “normal care,” but this is incorrect. The 16 affected patients and 25 healthy “noncontrol” subjects were given (1) no premedication that might affect BIS results, and (2) a slow, nonstandard sevoflurane induction. This is hardly “normal care.” This was a research protocol, and informed consent should have been obtained. That the authors’ institutional review board did not require it is very disquieting.
References
Morgan PG, Hoppel CL, Sedensky MM: Mitochondrial defects and anesthetic sensitivity. A nesthesiology 2002; 96: 1268–9Morgan, PG Hoppel, CL Sedensky, MM
Fujimoto S, Mizuno K, Shibata H, Kobayashi M, Sugiyama N, Ban K, Ishikawa T, Itoh T, Togari H, Wada Y: Serial electroencephalographic findings in patients with MELAS. Pediatr Neurol 1999; 20: 43–8Fujimoto, S Mizuno, K Shibata, H Kobayashi, M Sugiyama, N Ban, K Ishikawa, T Itoh, T Togari, H Wada, Y
Smith SJ, Harding AE: EEG and evoked potential monitoring in mitochondrial myopathies. J Neurol 1993; 240: 367–72Smith, SJ Harding, AE
Tulinius MH, Hagne I: EEG findings in children and adolescents with mitochondrial myopathies: A study of 25 cases. Brain Dev 1991; 13: 167–73Tulinius, MH Hagne, I
Rosow C, Manberg PJ: Bispectral index monitoring. Anesthesiol Clin North Am 2001; 19: 947–66Rosow, C Manberg, PJ