Sensitivity to Vasovagal Maneuvers in Normal Children and Adults ROBERT W. ARNOLD, M.D., * JOHN A. DYER, M.D., M.S., Department of Ophthalmology; ALLAN B. GOULD, Jr., M.D., Department of Anesthesiology; GEORGE G. HOHBERGER, M.D., Department of Ophthalmology; PHILLIP A. LOW, M.D., Department of Neurology In 15 male and 15 female healthy subjects who were 10 to 48 years of age, we studied alterations in heart rate and finger blood flow in response to the cold pressor test and four strong vasovagal maneuvers: diving response (apneic facial exposure to an ice water bag), Valsalva maneuver (forced expiration against a column of mercury to 40 to 50 mm Hg), unilateral carotid sinus massage, and oculocardiac reflex (inflation of a Honan balloon against one eye). Peripheral vasoconstriction as a consequence of the diving response paralleled the vasoconstriction from the cold pressor test, but it preceded the bradycardia that resulted from the diving response maneuver. In contrast, the rate of finger blood flow was high during the bradycardia that followed stage 4 of the Valsalva maneuver. Changes in heart rate correlated with age for the diving response, the Valsalva maneuver, and the oculocardiac reflex. Changes in heart rate and finger blood flow were not dependent on sex. The change in heart rate noted with the diving response was significantly correlated with that noted with the Valsalva maneuver and the oculocardiac reflex. Changes in finger blood flow did not correlate with changes in heart rate for any maneuver. This study provides a response profile of relative sensitivities to strong vasovagal maneuvers in normal children and adults. Profound bradycardia can be elicited by several nonpharmacologic maneuvers. Facial immer- sion in cold water (the diving response [DR]), *Current address: Ophthalmic Associates, Anchorage, Alaska. This study was supported in part by grants from Research to Prevent Blindness, the National Institute of Neurologi- cal and Communicative Disorders and Stroke (NS 14304, RO 1 NS 22352, and NO 1 NS 72302), the Muscular Dys- trophy Association, the Mogg fund, and the Mayo Founda- tion. Dr. Low is the recipient ofa Jacob Javits Neuroscience Investigator Award. Address reprint requests to Dr. P. A. Low, Department of Neurology, Mayo Clinic, Rochester, MN 55905. pressure on the eyeball or tension on the ex- traocular muscles (the oculocardiacreflex[OCRD, carotid sinus massage (CSM), and the Valsalva maneuver (VM) all evoke vagal bradycardia, but they seem to have different effects on peripheral sympathetic vasoconstrictor responses. Differ- ent afferent but similar efferent vagal neural components characterize these maneuvers. The OCR and DR share the trigeminal nerve as a primary afferent, whereas the afferents for VM and CSM include cranial nerves IX and X. The bradycardia produced by VM and CSM has been associated with hypotension and syncope. In contrast, mean arterial pressure is maintained during DR because of concomitant peripheral Mayo Clin Proc 66:797-804, 1991 797