Anesth Analg 2007;104:222
© 2007 International Anesthesia Research Society
doi: 10.1213/01.ane.0000249788.27880.b9
LETTER TO THE EDITOR
Editor-in-Chief Steven L. Shafer
Precipitous Bispectral Index Decline and Delayed Emergence After Lumbar Puncture
Jordan Blinder, MD,
Gregory Seaman, MD,
Kamel Ghandour, MD, and
Dennis Oh, MD
Department of Anesthesiology, Baystate Medical Center, Springfield, Massachusetts, Tufts University School of Medicine, Boston, Massachusetts, Jordan.Blinder{at}bhs.org (Blinder)
Department of Anesthesiology, Baystate Medical Center, Springfield, Massachusetts (Seaman, Ghandour)
Division of Neurosurgery, Baystate Medical Center, Springfield, Massachusetts (Oh)
To the Editor:
A 36-yr-old female presented for lumbo-peritoneal shunting to treat chronically increased cerebrospinal fluid (CSF) pressure, caused by cryptococcal meningitis. The preoperative neurologic examination was unremarkable except for diplopia and nystagmus. Neuroradiology revealed normal ventricles and no mass lesions. We elected to monitor with a bispectral index (BIS) in addition to standard hemodynamic monitors. We induced general anesthesia, intubated the patient’s trachea, and placed her in a left lateral decubitus position. She was maintained on sevoflurane at a stable inspired concentration. As part of the procedure we inserted a 14-G Tuohy needle into the intrathecal space at the L4-5 interspace. One-hundred milliliters of CSF was lost rapidly, and the BIS almost immediately decreased to values in the 5–20 range for approximately 12 min (Fig. 1. The patient’s vital signs remained stable. The procedure was completed without incident, and she awoke without deficit. Although we cannot exclude an artifact, there was no evidence that the abrupt decrease in BIS was due to equipment defect. We believe that the decrease in BIS reflected acute global hypoperfusion precipitated by the abrupt decrease in CSF, which rapidly resolved (1–4).
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