Muscle and skin sympathetic nerve traffic during physician and nurse blood pressure measurement

OBJECTIVE: Previous studies have shown that blood pressure assessment by a nurse markedly attenuates the pressor and tachicardic responses triggered by the physician blood pressure measurement. Whether and to what extent this attenuation reflects a different pattern of the neuroadrenergic responses to doctor or nurse blood pressure evaluation is unknown. METHODS: In 19 lean untreated mild essential hypertensive patients (age 39.1 ± 2.4 years, mean ± SEM), we measured beat-to-beat mean arterial pressure (Finapres), heart rate (ECG), and efferent postganglionic muscle and skin sympathetic nerve traffic [muscle sympathetic nerve activity (MSNA) and skin sympathetic nerve activity (SSNA), respectively, by microneurography], before, during, and following a 10-min sphygmomanometric BP measurement by a doctor or by a nurse unfamiliar to the patients. Measurements were repeated at a 30-min interval to obtain, in separate periods, muscle and skin sympathetic nerve traffic recordings. Both the sequences (doctor vs. nurse and muscle vs. skin sympathetic nerve traffic) were randomized. RESULTS: A doctor visit induced sudden, marked, and prolonged blood pressure and heart rate increases, accompanied by a muscle sympathetic nerve traffic inhibition (average response: -18.1 ± 4.3%, P < 0.01) coupled with a skin sympathetic nerve traffic excitation (average response: +46.1 ± 5.5%, P < 0.01). In contrast, a nurse visit elicited blood pressure and heart rate responses markedly and significantly reduced (-72.1 ± 11 and -81.7 ± 13% respectively, P < 0.01) as compared with those seen during the doctor's visit. This was the case also for muscle and skin sympathetic neural responses (-44.3 ± 9 and -65.6 ± 13%, P < 0.01). CONCLUSION: These data provide the first evidence that the blunted pressor and tachicardic responses to nurse's blood pressure measurements are accompanied by an attenuation of the adrenergic neural responses seen during the alerting reaction accompanying doctor's blood pressure measurement.