CIRCADIAN VARIATIONS OF BLOOD-PRESSURE IN PATIENTS WITH SEQUELAE OF CARBON-MONOXIDE POISONING

It has been shown that carbon monoxide poisoning causes necrosis of th e globus pallidum and the cerebral cortex, and a diffuse demyelination of the cerebral subcortical white matter, resulting in the impairment of the higher brain functions manifested as memory disturbances, apra xia, and agnosia. The purpose of the present study was to determine th e effects of the lesions in the brain caused by carbon monoxide poison ing on the circadian changes in blood pressure and pulse rate. We meas ured the ambulatory blood pressure in 15 male patients with the sequel ae of acute carbon monoxide poisoning and 16 age- and sex-matched cont rols. Using either brain computed tomography or brain magnetic resonan ce imaging, we determined that seven patients had lesions in the globu s pallidum bilaterally, four had lesions in the parietotemporooccipita l lobe bilaterally, and five had multiple deep white matter lesions. C ircadian variations of blood pressure and pulse rate did not show any significant differences in either group. The average 24-h blood pressu res were 120.8 +/- 2.2 (systolic)/74.1 +/- 1.5 mm Hg (diastolic) in th e patients and 117.4 +/- 2.7/74.5 +/- 2.1 mm Hg in the controls. The d aytime (6:00 to 21:00) and nighttime (21:00 to 6:00) blood pressures w ere 127.3 +/- 2.3/78.0 +/- 1.5 mm Hg and 109.7 +/- 2.4/67.4 +/- 1.7 mm Hg in the patients, and 121.6 +/- 2.9/77.5 +/- 2.2 mm Hg and 110.0 +/ - 2.7/69.3 +/- 1.8 mm Hg in the controls, respectively. Furthermore, t here were no differences in cardiovascular and plasma catecholamine re sponses induced by either a head-up tilt or a cold presser test betwee n the two groups. It is concluded that diffuse or multiple lesions in bilateral cerebral hemispheres caused by carbon monoxide poisoning per se do not affect the circadian changes in blood pressure and pulse ra te observed in normotensive subjects.