Diurnal Pressure Variation Research Articles

Anterior Optic Nerve Capillary Blood Flow Response to Diurnal Variation of Mean Ocular Perfusion Pressure in Early Untreated Primary Open-Angle Glaucoma

To examine the impact of diurnal variation in intraocular pressure (IOP) and mean ocular perfusion pressure (MOPP) on the variation in anterior optic nerve capillary blood flow (BF) in patients with untreated early primary open-angle glaucoma (uPOAG) and healthy volunteers. Fourteen patients with uPOAG (age, 56.3 +/- 12 years [SD]; seven men) and 14 normal subjects (age, 57.6 +/- 9.9 years; five men) were examined. Diurnal IOP, systolic (SBP) and diastolic (DBP) blood pressures, and optic nerve head (ONH) topography were measured every hour; and diurnal BF was measured by flowmeter every 2 hours between 0700 and 2200 hours. A perfusion image analyzer was used to calculate the mean BF within the rim (mean rim flow, MRF). The local flow (LF) was calculated using the median and mean flow rates within a 10 x 10-pixel window placed on the rim in the area of maximum topography fluctuation (MTF). The MOPP was then calculated. Mixed-effect linear models were used to analyze the repeated measures data in which both fixed and random effects were included. IOP, BP, and MOPP had significant diurnal variation (P < 0.040). LF measured at the sector of MTF significantly changed in patients with uPOAG (P = 0.006) but not in normal subjects (P = 0.660). MRF did not show significant diurnal change in either group (P = 0.130, P = 0.770). LF increased significantly after lunch in the uPOAG group (P = 0.001). SBP had a significant effect on LF over the course of the day in the uPOAG group (P = 0.043). The diurnal change in IOP, BP, and MOPP did not have a significant effect on MTF in either group. In uPOAG, the local flow, in areas of greatest topographical change, correlated inversely with IOP at 0700 hours (P < or = 0.002). The mean rim flow did not change during the day, implying that the anterior optic nerve capillary blood flow was autoregulated in both normal subjects and in patients with uPOAG, despite significant changes in IOP and MOPP. However, the regions of greatest diurnal change in rim topography (MTF) had significant diurnal change in capillary blood flow in patients with uPOAG but not in normal subjects.

Basal sediment evacuation by subglacial meltwater: suspended sediment transport from Haut Glacier d'Arolla, Switzerland

AbstractProglacial suspended sediment transport was monitored at Haut Glacier d'Arolla, Switzerland, during the 1998 melt season to investigate the mechanisms of basal sediment evacuation by subglacial meltwater. Sub‐seasonal changes in relationships between suspended sediment transport and discharge demonstrate that the structure and hydraulics of the subglacial drainage system critically influenced how basal sediment was accessed and entrained. Under hydraulically inefficient subglacial drainage at the start of the melt season, sediment availability was generally high but sediment transport increased relatively slowly with discharge. Later in the melt season, sediment transport increased more rapidly with discharge as subglacial meltwater became confined to a spatially limited network of channels following removal of the seasonal snowpack from the ablation area. Flow capacity is inferred to have increased more rapidly with discharge within subglacial channels because rapid changes in discharge during highly peaked diurnal runoff cycles are likely to have been accommodated largely by changes in flow velocity. Basal sediment availability declined during channelization but increased throughout the remainder of the monitored period, resulting in very efficient basal sediment evacuation over the peak of the melt season. Increased basal sediment availability during the summer appears to have been linked to high diurnal water pressure variation within subglacial channels inferred from the strong increase in flow velocity with discharge. Basal sediment availability therefore appears likely to have been increased by (1) enhanced local ice‐bed separation leading to extra‐channel flow excursions and[sol ]or (2) the deformation of basal sediment towards low‐pressure channels due to a strong diurnally reversing hydraulic gradient between channels and areas of hydraulically less‐efficient drainage. Copyright © 2005 John Wiley &amp; Sons, Ltd.

Seasonal evolution of runoff from Haut Glacier d'Arolla, Switzerland and implications for glacial geomorphic processes

Statistical classification of hydrograph form is used to elucidate the controls on diurnal runoff cycle evolution at Haut Glacier d'Arolla, Switzerland during the 1998 and 1999 melt seasons. Hydrographs are objectively grouped using statistical techniques into four principal types that are qualitatively interpreted as rising, falling, peaked-falling and peaked hydrographs. Peaked hydrographs are further grouped on the basis of the magnitude of their bulk flow, baseflow and diurnal flow components. Comparison with the evolution of meltwater sources and pathways demonstrates that runoff cycles evolve systematically during the melt season in response to removal of the seasonal snowpack from the ablation area. Peaked hydrographs predominate following the onset of snowpack removal and demonstrate an increasing and progressively earlier diurnal peak, but also an unusually low baseflow component that is probably due to surface melt mainly contributing direct to subglacial channels. Runoff cycle evolution has potentially significant geomorphic implications because peaked surface runoff cycles result in the formation of hydraulically efficient, channelised subglacial drainage and a significant increase in the gradient of the relationship between suspended sediment transport and discharge. Increasingly peaked diurnal cycles also result in increased basal sediment availability, most likely related to high diurnal water pressure variation within subglacial channels that may also have enhanced rates of basal sliding and hence subglacial erosion. Differences in runoff cycle form and evolution therefore have the potential to significantly influence glacial erosion rates and sediment yields.

Evolution of subglacial water pressure along a glacier’s length

AbstractObservations from along the length of Bench Glacier, Alaska, USA, show that the subglacial water-pressure field undergoes a multiphase transition from a winter mode to a summer mode. Data were collected at the glacier surface, the outlet stream, and in a network of 47 boreholes spanning the length of the 7 km long glacier. The winter pressure field was near overburden, with low-magnitude (centimeter to meter scale) and long-period (days to weeks) variations. During a spring speed-up event, boreholes showed synchronous variations and a slight pressure drop from prior winter values. Diurnal pressure variations followed the speed-up, with their onset associated with a glacier-wide pressure drop and flood at the terminus stream. Diurnal variations with swings of up to 80% of overburden pressure were typical of mid-summer. Several characteristics of our observations contradict common conceptions about the seasonal development of the subglacial drainage system and the linkages between subglacial hydrology and basal sliding: (1) increased water pressure did not accompany high sliding rates; (2) the drainage system showed activity characteristic of the spring season long before abundant water was available on the glacier surface; (3) the onset of both spring activity and diurnal variations of the drainage system did not show a spatial progression along the length of the glacier.

The Annual Behavior of the Semidiurnal and Diurnal Pressure Variations in East Antarctica

Abstract A 15-yr (1980–95) 3-hourly record of surface pressure from the Dome Concordia automatic weather station (74.30°S, 123.00°E; 3280 m MSL), located in East Antarctica, was analyzed to study the annual behavior of the semidiurnal and diurnal variation associated with atmospheric tides excited by heating due to insolation absorption by ozone and water vapor. The mean daily behavior of the pressure variation shows maxima around 0900 and 2100 LT. This variation is more intense during the austral winter. The time series of a Total Ozone Mapping Spectrometer (TOMS) were analyzed to study the correlation between the local pressure tidal oscillations and the annual behavior of total ozone over the globe. A clear correlation between the intensity of the pressure semidiurnal variation and global total ozone in both the annual and long-term trends was found. The mean annual behavior of the semidiurnal tides and global total ozone is very similar, with two maxima and one deep minimum. Maxima in semidiurnal tide...

Diurnal variation of episcleral venous pressure in healthy patients: a pilot study.

To study diurnal episcleral venous pressure (EVP) and its relation to intraocular pressure (IOP) in healthy patients. The influences of supine position and lid closure on EVP were also studied. Experimental observational study. Twelve healthy patients with no eye disease had their IOP and EVP measured at 16h00, 22h00, 22h30, 06h00, 06h30, 09h00, 12h00, and 16h00. Measurements at 22h30, 06h00, and 06h30 were performed on supine patients, and the measurement at 06h00 was with the eye that had been closed for the whole night. In a second experiment, EVP was measured on patients who were lying supine from 22h30 to 16h00 with one eye closed during the day. Episcleral venous pressure and IOP at varying time points during a 24-hour period. Episcleral venous pressure was relatively constant throughout the day except for a slight reduction at 22h00. After lying down, the EVP increased by 3.6 mm Hg and remained increased as long as the patient remained in this position. Eyelid closure did not affect EVP. IOP measured with the Tono-Pen closely followed the variations in EVP. Episcleral venous pressure remains relatively constant throughout the day. It increases in the supine position with a corresponding increase in IOP. Lid closure does not influence EVP or IOP.

Sea breezes and coastal jets in southeastern Spain

Sea breezes and low-level jet (LLJ) streams are studied in the region between the Eastern Castilla-La Mancha and the Mediterranean coast of southeastern Spain. The simplified concept of two-dimensional terrain and meteorological conditions explains the spatially and diurnally varying wind system consistently. The changes, as a function of time, height and distance to the coast, of temperature, pressure and wind as well as of certain observed phenomena, such as LLJs and strongly baroclinic zones, result from the response of the mesoscale flow to differential heating. Wind changes are generally found to be consistent with mesoscale changes in geostrophic winds as estimated from station pressure measurements. The LLJs mark the penetration depth of the sea breeze during daytime, where a baroclinic zone develops at the transition between continental air masses and marine air masses, typically at a distance of 150 km from the coast. The analysis is based on aerological data and ground-based measurements from the European Field Experiment in a Desertification Threatened Area (EFEDA) experiments in 1991 and 1994 as well as on 3-hourly data from three synoptic stations of the Spanish meteorological network for April–October in 1991 and 1994. After corrections were made for instrument errors and atmospheric tides, diurnal pressure variations document vertically integrated mass fluxes perpendicular to the coast. Amplitudes of diurnal pressure and temperature changes scatter significantly and are largest in midsummer. They are weakly correlated and pressure amplitudes remain large in spring and autumn when diurnal temperature changes are reduced. With about 6 h delay to the regular development of onshore winds at the coast during daytime, pronounced wind peaks are observed over the eastern plateau at Albacete and Barrax in the late afternoon. Case studies show that they are accompanied by development of baroclinically driven LLJs, whereas winds at Tomelloso, 220-km inland, show less pronounced diurnal changes and are beyond the normal penetration distance of sea breezes. Copyright © 2000 Royal Meteorological Society

Sea breezes and coastal jets in southeastern Spain

Sea breezes and low-level jet (LLJ) streams are studied in the region between the Eastern Castilla-La Mancha and the Mediterranean coast of southeastern Spain. The simplified concept of two-dimensional terrain and meteorological conditions explains the spatially and diurnally varying wind system consistently. The changes, as a function of time, height and distance to the coast, of temperature, pressure and wind as well as of certain observed phenomena, such as LLJs and strongly baroclinic zones, result from the response of the mesoscale flow to differential heating. Wind changes are generally found to be consistent with mesoscale changes in geostrophic winds as estimated from station pressure measurements. The LLJs mark the penetration depth of the sea breeze during daytime, where a baroclinic zone develops at the transition between continental air masses and marine air masses, typically at a distance of 150 km from the coast. The analysis is based on aerological data and ground-based measurements from the European Field Experiment in a Desertification Threatened Area (EFEDA) experiments in 1991 and 1994 as well as on 3-hourly data from three synoptic stations of the Spanish meteorological network for April–October in 1991 and 1994. After corrections were made for instrument errors and atmospheric tides, diurnal pressure variations document vertically integrated mass fluxes perpendicular to the coast. Amplitudes of diurnal pressure and temperature changes scatter significantly and are largest in midsummer. They are weakly correlated and pressure amplitudes remain large in spring and autumn when diurnal temperature changes are reduced. With about 6 h delay to the regular development of onshore winds at the coast during daytime, pronounced wind peaks are observed over the eastern plateau at Albacete and Barrax in the late afternoon. Case studies show that they are accompanied by development of baroclinically driven LLJs, whereas winds at Tomelloso, 220-km inland, show less pronounced diurnal changes and are beyond the normal penetration distance of sea breezes. Copyright © 2000 Royal Meteorological Society

Abnormalities of circadian rhythmicity in liver disease

U  conditions, a wide range of biological processes exhibit a diurnal rhythm of approximately 24 h (the term circadian arises from the Latin, circaΩapproximately, diemΩday). The most obvious rhythm is the one related to variations in the sleep/wake cycle, but almost all aspects of the internal environment undergo such changes over a 24-h period. This oscillation occurs in parallel to the daily alteration in external conditions that our rotatory planet imposes on all species. Thus, a teleological perspective of circadian function would posit that such internal organization allows adequate adaptation to the changing external environment. However, there is ample evidence to indicate that circadian rhythms arise from an internal time-keeping system that functions even in the absence of external cues (1). The existence of a ‘‘biological clock’’ with its afferent/efferent connections allows the organism to foresee and anticipate the modifications in the external environment that occur during the day/night cycle. Abnormal rhythms of several biological parameters have been described in patients with cirrhosis. The robustness of these findings will be influenced by the frequency of recording, and few studies have utilized continuous or very frequent samples in patients with liver disease. Furthermore, a diurnal variation cannot be truly termed circadian until it is shown that the rhythm persists under conditions of a constant external environment. Still, most biological oscillations are shown to persist under controlled circumstances, and diurnal variations under natural conditions can be viewed as reflecting circadian processes. Reports of abnormal rhythmicity in liver disease include such diverse processes as the lack of diurnal variation of arterial pressure in continuous 24-h recordings (2), the blunted rhythm of several hormones, such as angiotensin and aldosterone (3), the nocturnal rise in portal pressure (4) and alterations of the rhythm of plasma melatonin

Diurnal and long-term variations of lymph capillary pressure in health

The variability of pressure in the cutaneous lymph capillaries on the forefoot was determined in 2 groups of healthy volunteers. In group A, including 12 subjects (8 men, 4 women; mean age 28 years, range 22 to 37 years) measurements were performed in the morning and late afternoon of the same day. In group B (12 subjects, 5 women, 7 men; mean age 53 years, range 23 to 72 years) measurements of lymph capillary pressure were repeated within an interval of 7 weeks. The superficial microlymphatics were visualized by intravital fluorescence microlymphography, cannulated with glass micropipettes, and the lymph capillary pressure was measured using a servo-nulling pressure system. The lymph capillary pressure measured in the morning (mean 7.5±4.4 mm Hg; range −4 to 16 mm Hg) did not differ (p>0.05) from the pressure in the late afternoon (mean value 5.6±3.4 mm Hg; range −1 to 13 mm Hg). In group B initial lymph capillary pressure (mean 3.9±2.9 mm Hg, range −1.1 to 9.7 mm Hg) was not different (p>0.05) compared to the pressure after 7 weeks (2.9±2.7 mm Hg; range −1.0 to 6.8 mm Hg). In conclusion, lymph capillary pressure in healthy subjects does not exhibit significant changes during the daytime and the long-term reproducibility is good.

A Numerical Investigation of Cloud Diurnal Variations

Abstract The large-scale diurnal variation of cloud cover is derived from diurnal variations of temperature, density, water content, and static stability in a linearized calculation. Forced by the diurnal cycle of solar heating, the calculated cloud distribution is broadly consistent with observed diurnal variations under maritime nonconvective, maritime convective, and continental convective conditions. The calculated diurnal variation of low-cloud fraction follows primarily from the diurnal variation of temperature, which creates a diurnal variation of saturation vapor pressure. The calculated diurnal amplitude of low-cloud fraction is large under maritime nonconvective conditions, in which a well-mixed boundary layer promotes the transition between cloudy and clear conditions. The amplitude is further enhanced under continental conditions by the diurnal variation of vertical heat transport from the surface. The diurnal variation of high-cloud fraction under continental conditions follows primarily from...

Signal processing of diurnal and semidiurnal variations in radon and atmospheric pressure: A new tool for accurate in situ measurement of soil gas velocity, pressure gradient, and tortuosity

Signal processing of diurnal and semidiurnal variations of both atmospheric pressure and radon concentration in soil gases is shown to be useful for estimating soil gas transport parameters. The two daily‐cycle peaks at 12‐ and 24‐hour periods in the Power Spectral Density (PSD) of atmospheric pressure seem to be present everywhere on Earth's surface, and it is the effect of these regular pressure variations on the radon concentration in soil gases that makes it possible to determine three soil gas transport parameters which can be used to estimate real gas velocity; i.e. tortuosity τ, the ratio k/n between intrinsic permeability and effective porosity (that part of porosity involved in gas transport), and the pressure gradient α. The parameters k and n can be determined independently if the gas flux at the surface is measured at the same time. The method is robust, representative, and accurate: since it allows reliable estimation of transport parameters, it can provide relevant information about the depth of the radon source and the time it takes for information to reach the surface when radon bursts occur at depth. Radon is an appropriate soil gas tracer because it exists in all soils. Moreover, the measurement of radon concentration requires only passive sensors that do not hamper the rising gas column. Gas flux data obtained in Andalusia, Spain, in connection with mineral exploration are processed as examples. Determining the complete set of transport parameters helps in the interpretation of recorded radon outbursts, which are found to be correlated with regional seismic activity.

Borehole water-level variations and the structure of the subglacial hydrological system of Haut Glacier d’Arolla, Valais, Switzerland

AbstractLate-summer subglacial water pressures have been measured in a dense array of boreholes in the ablation area of Haut Glacier d’Arolla, Switzerland. Interpolated surfaces of minimum diurnal water pressure and diurnal water-pressure variation suggest the presence of a subglacial channel within a more widespread, distributed drainage system. The channel flows along the centre of a variable pressure axis (VPA), some tens of metres wide, that is characterized by low minimum diurnal water pressures (frequently atmospheric) and high diurnal water-pressure variations. These characteristics are transitional over a lateral distance of c. 70 m to higher and more stable subglacial water pressures in the adjacent distributed system. Water-pressure variations recorded in boreholes located close to the centre of the VPA reflect the delivery of surface-derived meltwater to the glacier bed and result in a diurnally reversing, transverse hydraulic gradient that drives water out from the channel into the distributed system during the afternoon and back to the channel overnight. Subglacial observations suggest that such flow occurs through a vertically confined sediment layer. Borehole turbidity records indicate that the resulting diurnal water flows are responsible for the mobilization and transport of fine debris in suspension. Analysis of the propagation velocity and amplitude attenuation cf the diurnal pressure waves suggests that the hydraulic conductivity of the sediment layer decreases exponentially with distance from the channel, falling from c. 10−4 m s−1 at the channel boundary to c. 10−7 m s−1 70 m away. These apparent hydraulic conductivities are consistent with Darcian flow through clean sand and typical glacial till, respectively.We suggest that fine material is systematically flushed from basal sediments located adjacent to large, melt-season drainage channels beneath warm-based glaciers. This process may have important implications for patterns of glacier erosion, hydro-chemistry and dynamics.

Borehole water-level variations and the structure of the subglacial hydrological system of Haut Glacier d’Arolla, Valais, Switzerland

AbstractLate-summer subglacial water pressures have been measured in a dense array of boreholes in the ablation area of Haut Glacier d’Arolla, Switzerland. Interpolated surfaces of minimum diurnal water pressure and diurnal water-pressure variation suggest the presence of a subglacial channel within a more widespread, distributed drainage system. The channel flows along the centre of avariable pressure axis(VPA), some tens of metres wide, that is characterized by low minimum diurnal water pressures (frequently atmospheric) and high diurnal water-pressure variations. These characteristics are transitional over a lateral distance of c. 70 m to higher and more stable subglacial water pressures in the adjacent distributed system. Water-pressure variations recorded in boreholes located close to the centre of the VPA reflect the delivery of surface-derived meltwater to the glacier bed and result in a diurnally reversing, transverse hydraulic gradient that drives water out from the channel into the distributed system during the afternoon and back to the channel overnight. Subglacial observations suggest that such flow occurs through a vertically confined sediment layer. Borehole turbidity records indicate that the resulting diurnal water flows are responsible for the mobilization and transport of fine debris in suspension. Analysis of the propagation velocity and amplitude attenuation cf the diurnal pressure waves suggests that the hydraulic conductivity of the sediment layer decreases exponentially with distance from the channel, falling from c. 10−4m s−1at the channel boundary to c. 10−7m s−170 m away. These apparent hydraulic conductivities are consistent with Darcian flow through clean sand and typical glacial till, respectively.We suggest that fine material is systematically flushed from basal sediments located adjacent to large, melt-season drainage channels beneath warm-based glaciers. This process may have important implications for patterns of glacier erosion, hydro-chemistry and dynamics.

A possible signal of the El Niño‐Southern Oscillation in time series of the diurnal tide

Long time series of diurnal pressure variations, S1(p), at Macao (22° N,113°E) and Batavia (now Djakarta: 6°S, 107°E) are analysed, and, at both locations, a correlation is found between S1(p) and El Niño‐Southern Oscillation (ENSO). Some possible physical explanations for this correlation are given.

Diurnal blood pressure variation and dietary salt in spontaneously hypertensive rats.

We have previously reported that high dietary salt exposure significantly increases daytime mean arterial pressure in spontaneously hypertensive rats (SHR) but not in normotensive Wistar-Kyoto (WKY) controls. In the present study, we used a telemetry monitoring system to evaluate the effects of high dietary salt exposure on diurnal variation of mean arterial pressure and heart rate in SHR and WKY rats. After implantation of a radio frequency transducer, SHR and WKY rats were maintained on either high (8%) or basal (1%) salt diets. Hemodynamic values were then analyzed for diurnal variation with the use of a nonlinear data-fitting program. After 2 weeks of dietary exposure, high salt-fed SHR had significantly greater 24-hour mean arterial pressure (156 +/- 3 mmHg) than SHR receiving basal (135 +/- 2 mmHg) and WKY rats receiving high (100 +/- 2 mmHg) or basal (100 +/- 1 mmHg) salt diets. Rhythm analysis indicated significant increases in both daytime and nighttime mean arterial pressure during high salt exposure in SHR. In WKY rats, high salt exposure increased nighttime but not daytime mean arterial pressure, with no net effect on 24-hour mean arterial pressure. High dietary salt exposure significantly decreased heart rate in both SHR and WKY rats, and it did not significantly alter the pattern of diurnal blood pressure or heart rate variation. These results indicate that WKY rats manifest an acute sensitivity to salt ingestion but have compensatory mechanisms sufficient to prevent sustained increases in mean arterial pressure; such mechanisms are lacking in SHR.

Atmospheric Tides on Venus. IV. Topographic Winds and Sediment Transport

Solar heat absorbed by the soil of Venus is rapidly deposited in its atmosphere. This exchange drives small diurnal temperature and pressure variations. These in turn generate periodic winds of a few meters per second and surface stresses capable of blowing sand-size grains along the surface of Venus. This paper presents a new theory of the Venus boundary layer which includes the effects of topography. Use of the mixing-length hypothesis eliminates the unknown eddy viscosity. Maps of predicted mass flux and erosion/deposition rates are presented, based on the relief measured by the Pioneer Venus orbiter. Regional slopes dominate the wind field and corresponding mass transport. Typical friction speeds are ∼19 cm/s, several times those estimated from Venera 9 and 10 anemometer data. Mean aeolian transport is generally away from the equator, contrary to the prevailing direction of wind streaks seen by the Magellan orbiter. Including a steady Hadley circulation can correct the wind direction, but not the friction speeds.

半乾燥地域で夕方に観測された水蒸気圧の顕著なピークについて

Significant evening peaks were observed in the diurnal variations of vapor pressure over an oasis surrounded by desert in the north-west part of China. They appeared not only in the surface layer measurement but also in the upper air soundings below 500 m. According to the surface flux measurements, it was observed that sensible heat flux was much stronger over the desert than over the oasis during the daytime. The upper-air sounding data shows that the oasis is a cool and moist island capped by dry and hot air which would be advected from the surrounding desert. In these situations, upper-layer convective mixing is considered to be much stronger than in the lower cool island, and this can lead to water vapor flux divergence in the afternoon. In the evening, convective mixing, which is suggested by the sensible heat flux from the ground, decreases over the desert and in the upper layer over the oasis. It was observed that evapotranspiration from the surface still continues upward. It is suggested that water vapor flux convergence can occur near the oasis surface.

Diurnal Surface-Pressure Variations over the Continental United States and the Influence of Sea Level Reduction

Abstract This paper presents the results of a detailed study of the diurnal and semidiurnal pressure variations at the surface across the continental United States. Using a larger dataset than preceding studies and a variety of analysis approaches, the spatial and temporal variations in the diurnal and semidiurnal components of station and sea level pressure are described, and the influence of current pressure reduction techniques on the characteristics of sea level pressure is evaluated. It is shown that the temperature-averaging scheme currently used in sea level pressure reduction creates a bogus semidiurnal signal in sea level pressure over high terrain. This paper also describes the summertime mesoscale evolution of station pressure over the northeast United States and presents 3-h pressure-change maps for the continental United States during the summer and winter seasons.

A Study of the Effects of Delapril, a New Angiotensin Converting Enzyme Inhibitor, on the Diurnal Variation of Arterial Pressure in Patients With Essential Hypertension Using Indirect and Direct Arterial Pressure Monitoring Methods

In order to investigate the effect of delapril, a new angiotensin converting enzyme inhibitor, on the diurnal variation of arterial pressure in patients with essential hypertension, this study examined 24 h arterial pressure using an indirect or a direct monitoring system. When the effect of twice-a-day administration of delapril at daily doses of 30 to 90 mg was examined using the indirect monitoring system in 12 outpatients, delapril decreased systolic and diastolic arterial pressures significantly only at limited points during the day. However, each of the averaged 24 h daytime and nighttime arterial pressures showed significant reductions. The 24 h intraarterial pressure monitoring demonstrated that delapril decreased systolic and diastolic arterial pressure at most of the measurement points. The arterial pressure reductions during daytime and nighttime were not significantly different, that is, there was no excessive reduction in nighttime arterial pressure. Heart rate and its variability were virtually unaffected by the delapril treatment in either monitoring study. No adverse reactions were observed in the indirect or direct monitoring studies. Thus, it is concluded that twice-a-day administration of delapril at daily doses of 30 to 90 mg brings about a safe and stable antihypertensive effect, without affecting the diurnal variation of arterial pressure.