Chronobiologic vs. sphygmomanometric assessment of hypertension in a hospital setting

The aim of this study was to assess the possible correlations between casual measurements and automatic monitoring analyzed with the chronobiologic technique in hospitalized hypertensive patients. Forty-three patients (24 men and 19 women) with mild to moderate essential hypertension were studied in an open hospital ward 5 to 7 days after admission. Meal times, sleep times, and visiting hours were standardized. A clinical value of blood pressure was calculated as the arithmetic mean of three sphygmomanometric measurements taken in the morning (patient seated; 5-min interval between measurements). Then, a basal value of blood pressure was considered as the lowest systolic and the lowest diastolic blood pressure among six sphygmomanometric measurements obtained every 5 min (patient supine). Noninvasive, automatic recording of blood pressure was also obtained every 15 min for 24 hours by a quasiportable oscillometric instrument. Blood pressure recordings were analyzed according to the "cosinor" method of Halberg. On average, clinical blood pressure was 160/96 +/- 14/10 mmHg, significantly higher (p less than 0.005) than either basal blood pressure (150/91 +/- 12/8 mmHg) or 24-h recorded blood pressure mesor (144/88 +/- 13/9 mmHg). The differences were not entirely due to diurnal variations, since morning casual measurements were significantly higher than daytime average blood pressure. A chronobiologic assessment of hypertension in hospitalized patients is more representative of true blood pressure behavior, not only because of the multiple recordings but also because of the absence of an alarm reaction that may trigger a pressor response.