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Letters To The Editor: Letters & Announcements

This Little Piggy Went to MRI: The Tale of the Toe Test

Auden, Steve M. MD

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doi: 10.1097/00000539-200107000-00051
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Some pediatric patients (and the occasional adult) require sedation or general anesthesia to tolerate imaging studies. IV propofol is frequently selected for this purpose and dose requirements for these nonstimulating procedures have been reported (1). Individual patient needs, though, may vary. Somewhat simpler than “target controlled infusion” calculations is titration of propofol by use of the “toe test.” A digital nail bed (usually a toe, as this does not require movement of the imaging sled) is firmly compressed. If this painful stimulus elicits no response, the patient is “too deep.” If movement of other extremities, head, or trunk occurs, the patient is “too light.” If slight withdrawal of the stimulated extremity is seen, the patient is “just right.”

Clinical experience indicates that when this level of sedation/analgesia is maintained, the vast majority of patients will breathe spontaneously without assistance or instrumentation, have stable hemodynamics, and awaken rapidly and smoothly. Long-term follow-up on living happily-ever-after is underway.

Steve M. Auden, MD


1. Frankville DD, Spear RM, Dyck JB. The dose of propofol required to prevent children from moving during magnetic resonance imaging. Anesthesiology 1993; 79: 953–8.
© 2001 International Anesthesia Research Society