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At least 253 records · Page 14Linked to original sources
PubMed1995

Effect of moderately increased intrapelvic pressure on renal tissue pressure and vasopressin release in rabbits.

Electrical stimulation of afferent renal nerves and activation of intrarenal receptors increases plasma vasopressin concentration, but the role of afferent renal nerves in the control of vasopressin secretion is not clear. Recently, we reported that activation of renal mechanoreceptors stimulates the release of vasopressin. However, intrapelvic pressure was increased to 50 mmHg, and this increase is above the normal physiological range. Therefore, in the present study, we investigated the effect of moderately increased intrapelvic pressure on plasma vasopressin concentration in anesthetized rabbits. First, we measured renal tissue pressure while intrapelvic pressure was increased stepwise in 10-mmHg increments. Basal renal tissue pressure was 17 +/- 2 mmHg. Renal tissue pressure increased only when intrapelvic pressure was higher than the basal tissue pressure of each animal. Usually, increases in intrapelvic pressure less than 20 mmHg did not increase renal tissue pressure. This finding suggests that only increases in intrapelvic pressure more than 20 mmHg can activate renal mechanoreceptors. Based on this finding, the effects of moderate increases in intrapelvic pressure (15 and 30 mmHg) were studied. With a 15-mmHg increase in intrapelvic pressure, plasma vasopressin concentration did not change significantly. However, when intrapelvic pressure was increased to 30 mmHg, plasma vasopressin concentration increased from 5.6 +/- 1.4 to 9.5 +/- 2.8 pg/ml at 5 min (p < 0.05) and to 8.8 +/- 2.0 pg/ml at 10 min (p < 0.05). Plasma renin activity and mean arterial pressure also increased when intrapelvic pressure was increased to 30 mmHg. We conclude that moderate increases in intrapelvic pressure stimulate vasopressin secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1999

Self-adjusting nasal continuous positive airway pressure therapy based on measurement of impedance: A comparison of two different maximum pressure levels.

STUDY OBJECTIVE: Automatic titration using the forced oscillation technique (FOT) has recently been developed for the treatment of obstructive sleep apnea syndrome (OSAS). So far, it is not known if therapy with automatic nasal continuous positive airway pressure (nCPAP) using a preset upper pressure limitation or a free range (which might lead to higher mean pressure) is preferable with regard to obstructive events, sleep stages, and pressure characteristics. DESIGN: After diagnostic polysomnography, patients were randomly assigned to two settings with the self-adjusting nCPAP (APAP) device based on the FOT. In mode 1, the pressure variation ranged from 4 to 15.5 cm H(2)O, and in mode 2, the pressure variation ranged from 4 cm H(2)O to an individual upper pressure limit. PATIENTS: Eleven men, aged 53.0 +/- 6.8 years with a body mass index of 32.4 +/- 5.1 kg/m(2) and an apnea-hypopnea index (AHI) of 31.6 +/- 26.6/h. MEASUREMENTS AND RESULTS: Manually titrated pressure was at 9.3 +/- 2.1 cm H(2)O, the mean pressure in mode 1 was 5.4 +/- 1.0 cm H(2)O (p < 0.01), and the mean pressure in mode 2 was 5.1 +/- 0.7 cm H(2)O (p < 0.01). A reduction of respiratory events (baseline AHI, 31.6 +/- 26.6/h; AHI in mode 1, 3.4 +/- 4.5; AHI in mode 2, 5.0 +/- 7.2; each with p < 0.001) and an increase in the "rapid eye movement" stage of sleep (baseline, 13.0 +/- 5.5%; mode 1, 22.0 +/- 7.7 [p < 0. 05]; mode 2, 23.0 +/- 7.9 [p < 0.01]) were achieved. In mode 1, the mean pressure was below the manual pressure 91.7 +/- 9.3% of the time, and in mode 2, the mean pressure was below the manual pressure 90.4 +/- 6.3% of the time. The manual pressure was exceeded by 5.5 +/- 7.4% (mode 1) and by 5.2 +/- 3.1% (mode 2). CONCLUSION: We conclude that nCPAP therapy based on the FOT permits the adequate treatment of OSAS with significantly lower pressure than manually titrated nCPAP therapy does. A presetting of an upper pressure limit has no advantage compared to free range.

Adult↗
PubMed1983

Effects of airway pressure and lung volume on left ventricular transmural pressure-volume relationships in humans.

Positive airway pressure, combined with increased lung volume, decreases left ventricular compliance in dogs. To determine whether airway pressure or lung volume influences left ventricular diastolic properties in humans, we examined two consecutive cineangiograms with simultaneous esophageal and left ventricular pressure recordings in 14 patients. Both studies were performed during sustained inspiration, one with atmospheric airway pressure, and one with positive airway pressure (9.1 +/- 2.4 mm Hg). Positive pressure caused higher transpulmonary (airway minus esophageal) pressure and therefore greater lung volume in 10 of 14 patients, while four patients had lower transpulmonary pressures due to decreased inspiratory effort. When positive airway pressure and increased lung volume were present together (n = 10), left ventricular transmural (ventricular minus esophageal) pressure-volume curves revealed higher transmural pressures at comparable diastolic ventricular volumes. For example, at end-diastole mean left ventricular transmural pressure was 25.2 +/- 12.9 mm Hg (compared to 20.8 +/- 12.3 mm Hg during control studies, p less than 0.05), while ventricular volume was unchanged (189 +/- 87 compared to 185 +/- 81 ml, p = NS). When all 14 patients were considered together, this effect was linked more closely to higher transpulmonary pressure than to positive airway pressure. We conclude that human left ventricular transmural pressure-volume relationships are influenced by airway pressure and lung volume. Our findings further suggest that lung volume may be more important than airway pressure in this regard.

Coronary Disease↗
PubMed2004

Direct intra-aneurysm sac pressure measurement using tip-pressure sensors: in vivo and in vitro evaluation.

OBJECTIVE: Direct intra-aneurysm sac pressure measurement with percutaneous translumbar puncture is a new method for follow-up after endovascular aneurysm repair. The purpose of this study was to evaluate a tip-pressure sensor system for intra-aneurysm pressure measurement in an in vitro aneurysm model and in vivo in patients by studying intraobserver variability. METHODS: We used 0.014-inch guide wire-mounted tip-pressure sensors. For the in vitro aneurysm model, saccular aneurysms filled with thrombus were inserted in a left-heart-driven aneurysm model. Pressure was measured simultaneously with guide wire pressure sensors in the lumen of the model and within the aneurysm thrombus. In vivo, intraobserver variability was evaluated with double percutaneous translumbar puncture of the abdominal aortic aneurysm (AAA) with pressure measurement in 15 patients (14 men, 1 woman; median age, 75 years [63-80 years]; median AAA diameter, 55 mm [47-80 mm]) at a median of 32 months (2-100 months) after endovascular aneurysm repair. Mean pressure index was calculated as the percentage of mean intraaneurysm pressure relative to simultaneous mean systemic pressure. RESULTS: In vitro, the difference in pressure between the tip-sensor measurements and the pressure output of the aneurysm model was 2 mm Hg (1-4 mm Hg) when the output varied between 150/50 and 200/100 mm Hg (n = 90). Mean pressure in the lumen of the model and within the aneurysm thrombus differed by 1 mm Hg (-5-15 mm Hg (n = 10). In vivo, intraobserver variability of mean pressure index (Bland-Altman plot) was 0% (-7%-17%; n = 15%). CONCLUSION: Direct intra-aneurysm sac pressure measurement with tip-pressure sensors mounted on 0.014-inch guide wires is a reliable and reproducible technique for measuring intra-AAA pressure both in vitro and in vivo.

Aged↗
PubMed2003

Theoretical and experimental studies on freezing point depression and vapor pressure deficit as methods to measure osmotic pressure of aqueous polyethylene glycol and bovine serum albumin solutions.

For survival in adverse environments where there is drought, high salt concentration or low temperature, some plants seem to be able to synthesize biochemical compounds, including proteins, in response to changes in water activity or osmotic pressure. Measurement of the water activity or osmotic pressure of simple aqueous solutions has been based on freezing point depression or vapor pressure deficit. Measurement of the osmotic pressure of plants under water stress has been mainly based on vapor pressure deficit. However, differences have been noted for osmotic pressure values of aqueous polyethylene glycol (PEG) solutions measured by freezing point depression and vapor pressure deficit. For this paper, the physicochemical basis of freezing point depression and vapor pressure deficit were first examined theoretically and then, the osmotic pressure of aqueous ethylene glycol and of PEG solutions were measured by both freezing point depression and vapor pressure deficit in comparison with other aqueous solutions such as NaCl, KCl, CaCl(2), glucose, sucrose, raffinose, and bovine serum albumin (BSA) solutions. The results showed that: (1) freezing point depression and vapor pressure deficit share theoretically the same physicochemical basis; (2) theoretically, they are proportional to the molal concentration of the aqueous solutions to be measured; (3) in practice, the osmotic pressure levels of aqueous NaCl, KCl, CaCl(2), glucose, sucrose, and raffinose solutions increase in proportion to their molal concentrations and there is little inconsistency between those measured by freezing point depression and vapor pressure deficit; (4) the osmotic pressure levels of aqueous ethylene glycol and PEG solutions measured by freezing point depression differed from the values measured by vapor pressure deficit; (5) the osmotic pressure of aqueous BSA solution measured by freezing point depression differed slightly from that measured by vapor pressure deficit.

Freezing↗
PubMed1998

A comparison of pharyngeal mucosal pressure and airway sealing pressure with the laryngeal mask airway in anesthetized adult patients.

UNLABELLED: We measured pharyngeal mucosal pressures at six different locations on the laryngeal mask airway (LMA) and tested the hypothesis that the efficacy of the seal is not related to pharyngeal mucosal pressure. Twenty anesthetized, paralyzed adult patients were studied. Microchip sensors were attached to the size 5 LMA at locations corresponding to the lateral and posterior pharynx, the hypopharynx, the pyriform fossa, the base of tongue, and the oropharynx. Mucosal pressures and airway sealing pressures were recorded during inflation of the cuff from 0 to 40 mL in 10-mL increments. The highest mean mucosal pressure was in the oropharynx (26 cm H2O), and the lowest was in the posterior pharynx (2 cm H2O). Mucosal pressures increased with increasing intracuff pressure and cuff volume, but the rate of increase varied among locations. Airway sealing pressure increased with increasing intracuff volume from 0 to 10 mL (P < 0.0001) and 10 to 20 mL (P = 0.0001), was unchanged from 20 to 30 mL, and decreased from 30 to 40 mL (P = 0.005). The airway sealing pressure was higher than pharyngeal mucosal pressure until the intracuff volume was > or =30 mL. There was no correlation between mucosal pressures and airway sealing pressure at any location. We conclude that the efficacy of the seal is not related to pharyngeal mucosal pressure. Pharyngeal mucosal pressures are generally lower than those considered safe for the tracheal mucosa during prolonged intubation. IMPLICATIONS: We measured pharyngeal mucosal pressures at six different locations on the laryngeal mask airway and showed that the efficacy of the seal is not related to pharyngeal mucosal pressure. Pharyngeal mucosal pressures are generally lower than those considered safe for the tracheal mucosa during prolonged intubation.

Adult↗
PubMedDate not supplied

Do custom-fitted pressure garments provide adequate pressure?

Pressure garment therapy has become the worldwide standard of care for the prevention and treatment of hypertrophic scars. There are many reports in the literature on pressure garment therapy but few studies state the amount of pressure actually provided. The purpose of our study was to determine the amount of pressure applied to the scar/garment interface by custom-fitted pressure garments. The Iscan (Tekscan, Inc.) system was used to document scar/garment interface pressures of 144 new custom-fitted pressure garments. Average pressure readings for garments for the anterior thigh, anterior trunk, abdomen, buttocks, posterior trunk, posterior thigh, and arm were less than 22 mm Hg. Average pressure readings for the dorsal hand, leg, forearm, and dorsal foot were more than 28 mm Hg, with smaller relative standard deviations. The pressure readings varied greatly between garments in this group, frequently resulting in standard deviations that were higher than the pressure readings. The data show that despite precise fitting techniques, pressure garments do not provide a consistent amount of pressure at the scar/garment interface. This means that studies that report results of pressure therapy, but do not verify the amount of pressure applied, are of limited value. Precise determination of pressure "dose" must be made before the efficacy of pressure garment therapy can be determined objectively.

Burns↗
PubMed2003

What is the most important component of blood pressure: systolic, diastolic or pulse pressure?

PURPOSE OF REVIEW: Diastolic blood pressure has traditionally been considered the most important component of blood pressure and the primary target of antihypertensive therapy. However, over 30 years ago important epidemiological studies pointed out the importance of systolic blood pressure, and research during the 1990s has strengthened this view. Unlike diastolic blood pressure, systolic blood pressure increases progressively with age, and in the ageing societies elevated systolic pressure is the most common form of hypertension. The characteristic changes of systolic and diastolic blood pressure with age lead to increases in pulse pressure (systolic minus diastolic), which has emerged as a new, potentially independent risk factor. In this review we compare the relative importance of various blood pressure components. RECENT FINDINGS: Generally, in studies in which readings of systolic and diastolic blood pressure have been compared, systolic blood pressure has been a better predictor of risk. Moreover, isolated systolic hypertension predicts risk better than isolated diastolic hypertension, and the treatment of both isolated systolic hypertension and combined hypertension has reduced cardiovascular events. There are no treatment studies of isolated diastolic hypertension. Pulse pressure reflects stiffening of large arteries and is associated with several cardiovascular risk factors. Pulse pressure also predicts events in epidemiologic studies, but elucidation of an independent role is hampered by the close correlation between pulse pressure and systolic blood pressure. SUMMARY: Epidemiological and treatment studies suggest that systolic blood pressure should be the primary target of antihypertensive therapy, although consideration of systolic and diastolic pressure together improves risk prediction. The greatest practical concern at the moment is the undertreatment of hypertension, especially systolic, and total cardiovascular risk.

Antihypertensive Agents↗
PubMed2005

Accuracy of oscillometric blood pressure monitoring with concurrent auscultatory blood pressure in hemodialysis patients.

BACKGROUND: Oscillometric devices are commonly used to measure blood pressure and their validation entails sequential measurements of auscultated and oscillometric blood pressures. It is unknown whether simultaneous measurement of auscultated blood pressure and concurrent digitization and recording of the sounds can improve assessment of such devices. The aim of this study was to develop a technique of simultaneous measurement of blood pressure using oscillometric and auscultated measurements in the same deflation. Using such a device, we validated the Omron HEM-907 blood pressure measuring device in hemodialysis patients. METHODS: Twenty non-hypertensive subjects and 20 hemodialysis patients were studied. Six blood pressure readings were obtained in each participant; three readings were obtained using the automatic, oscillometric mode of Omron HEM-907 and three readings were obtained using the manual mode of the Omron HEM-907. In each situation, simultaneous digitized Korotkoff sounds and manometric pressures were recorded. The grading scale indicated by the British Hypertension Society protocol was used to assess the device. RESULTS: Systolic blood pressure measured simultaneously by digitized sound and pressures agreed closely for systolic pressure (Grade A for both hemodialysis and normal controls) but not for diastolic pressure (Grade C for both hemodialysis and controls). Sequential comparison of oscillometric readings with auscultated systolic and diastolic pressure yielded a Grade B for both hemodialysis patients and controls. When concurrent digitized systolic readings were used, however, Grade A was achieved for both populations for systolic readings, but Grade C for diastolic readings. The mean differences (SD) between the oscillometric and auscultatory blood pressure reading in normal controls were 4.3 (8.9) and 0.6 (8.7) for systolic and diastolic blood pressures, respectively. In hemodialysis patients, the mean differences (SD) were 2.7 (9.3) and 0.4 (7.0) for systolic and diastolic blood pressures, respectively. CONCLUSION: Simultaneous measurement of digitized Korotkoff sounds and pressure can improve the assessment of devices for systolic but not diastolic blood pressure. The Omron HEM-907 device can be recommended for use in hemodialysis patients.

Adult↗
PubMed1992

Use of non-invasive finger blood pressure monitoring in the estimation of aortic pressure at rest and during the Mueller manoeuvre.

The aim of this investigation was to evaluate whether reliable estimates of aortic pressure can be derived using non-invasive finger blood pressure monitoring. Finger blood pressure (Ohmeda 2300 Finapres device; Finapres, Englewood, CO) was compared with simultaneous ascending aortic pressure measured with a catheter-transducer system both at rest and during acute negative intrathoracic pressure (the Mueller manoeuvre). Thirty-eight patients aged 17-73 years were studied. All were undergoing routine diagnostic or therapeutic cardiac catheterization. Beat-to-beat values of systolic, diastolic and mean non-invasive finger and invasive aortic blood pressure were measured at rest and factors which might have an influence on the difference between methods were examined. The mean finger-aortic difference was +5 +/- 14 mmHg for systolic, -2 +/- 7 mmHg for diastolic, -5 +/- 8 mmHg for mean and +6 +/- 13 mmHg for pulse pressure. In multivariate linear regression analysis, the difference in systolic pressure was related to aortic systolic pressure (standardized coefficient beta = -0.33, P = 0.01), heart rate (beta = 0.49, P < 0.000), age (beta = -0.29, P < 0.025) and height (beta = 0.40, P < 0.005). The linear regression equations to derive resting aortic pressures from the non-invasive finger pressure readings had correlation coefficients between 0.83 and 0.87 and standard errors of estimate between 6 and 14 mmHg. During the Mueller manoeuvre, Finapres reproduced average pressure changes reliably compared with intra-aortic pressure. Due to moderate inter-individual variation in the finger-aortic differences the correlation coefficients ranged from 0.83 to 0.93 and the standard errors of estimate from 3 to 6 mmHg. Non-invasive finger blood pressure monitoring could be used to estimate central aortic mean and diastolic blood pressure fairly reliably at rest, but with respect to systolic pressure the variance in finger-aortic difference was marked. The average intra-aortic pressure changes caused by the Mueller manoeuvre were reliably reproduced by the Finapres device.

Adolescent↗
PubMed1984

How alterations in pleural pressure influence esophageal pressure.

Although esophageal pressures have been substituted for direct pleural pressure measurement in humans, we have investigated the validity of this approach under circumstances when left and right pleural pressures are not equal. Esophageal and bilateral pleural pressures in awake sheep were compared by using matched balloon catheters in close proximity. In standing sheep, both end-expiratory pressures and inspiratory pressure swings were similar in all three catheter systems. However, when pleural pressures were made unequal, as during lateral recumbency or unilateral pneumothorax, the esophageal pressure reflected predominantly the right pleural pressure. These results suggest that esophageal pressures are useful estimates of pleural pressure under normal conditions when pleural pressures are equal bilaterally. However, the usefulness of esophageal pressures is limited in the presence of unilateral pneumothorax or other conditions where left and right pleural pressures are unequal. In the lateral decubitus position, positive end-expiratory pleural pressures were consistently observed. This was believed to be due to a combination of contraction of expiratory muscles, rapid respiratory rate resulting in insufficient expiratory time to reach an equilibrium pressure, and increased airways resistance resulting from compression of the dependent lung by the abdominal viscera. A single study in a paralyzed ventilated sheep showed less positive expiratory pressures, which were further reduced to zero or less when the respiratory rate was slowed to 10 breaths/min.

Abdominal Muscles↗
PubMed1987

Right heart pressure does not equal pericardial pressure in the potassium chloride-arrested canine heart in situ.

Recently proposed concepts of pericardial surface pressure, as opposed to liquid pressure, have advanced our understanding of the relationship between pericardial and heart chamber pressures. However, the subsequent suggestion that right heart intracavitary pressure equals, or nearly equals, pericardial surface pressure is not strictly consistent with the physiology of pericardial constraint. If right heart pressure equals pericardial surface pressure, then transmural right heart pressure equals zero. Because of the difficulty in measuring pericardial pressure directly in the beating heart we designed an experiment in the recently arrested canine heart in situ to measure pericardial pressure indirectly and to test the hypothesis that right heart transmural pressure is zero under reasonably physiologic, static equilibrium conditions. According to a static equilibrium analysis of the pressures acting across the walls of the heart, at a given volume the change in right heart pressure caused by removing the pericardium is equal to the pericardial pressure when the pericardium is intact. We found that this drop in pressure caused by pericardiectomy did not equal right heart pressure and therefore that right heart transmural pressure does not equal zero.

Animals↗
PubMed1985

Influence of airway pressure waveform on cardiac output during positive pressure ventilation of healthy newborn dogs.

During positive pressure ventilation, increases in mean airway pressure produced by increases in end expiratory pressure are associated with reductions in cardiac output. Mean airway pressure may be increased not only by increasing end expiratory pressure, but also by increasing the inspiratory pressure or the inspiratory to expiratory time ratio. During positive pressure ventilation of 10 healthy newborn dogs, cardiac output and left ventricular dimensions were measured using radioactive microspheres and echocardiography, respectively. Baseline ventilation was produced using the least inspiratory pressure to maintain normocarbia (rate = 50 min-1, inspiratory to expiratory time ratio = 1:3, end expiratory pressure = 2 cm H2O). The mean airway pressure was increased 3-fold by independently changing the airway pressure waveform through increases in inspiratory pressure, inspiratory to expiratory time ratio, or end expiratory pressure. Despite differences in airway pressure waveform, similar reductions in left ventricular dimension, cardiac output, and stroke volume were seen. We conclude that at a given increased mean airway pressure during positive pressure ventilation, the reduction in cardiac output is independent of the airway pressure waveform.

Animals↗
PubMed1994

Compartment pressure in association with closed tibial fractures. The relationship between tissue pressure, compartment, and the distance from the site of the fracture.

We studied twenty-five consecutive patients who had a closed tibial fracture to determine whether there was a relationship between compartment pressure and the distance at which the pressure was measured from the site of the fracture. Tissue pressure was measured in all four compartments of the leg at the level of the fracture and at five-centimeter increments proximal and distal to the fracture. The peak pressure was usually found at the level of the fracture and was always located within five centimeters of the fracture. The highest pressures were recorded in the anterior and the deep posterior compartments in twenty patients, including all five of those who had had a fasciotomy. The measured pressure decreased steadily when sampled at increasing distances proximal and distal to the site of the highest recorded pressure. Decreases of twenty millimeters of mercury (2.67 kilopascals) five centimeters adjacent to the site of the peak pressure were common. Compartment syndrome was diagnosed in five patients on the basis of clinical findings, and the diagnosis was confirmed when peak compartment pressures of more than the critical threshold (within twenty millimeters of mercury [2.67 kilopascals] of the diastolic blood pressure) were recorded. Three of these five patients had measured pressures that were less than the critical threshold within five centimeters of the site of the peak pressure. Failure to measure tissue pressure within a few centimeters of the zone of peak pressure may result in a serious underestimation of the maximum compartment pressure. Our results suggest that measurements should be performed in both the anterior and the deep posterior compartments at the level of the fracture as well as at locations proximal and distal to the zone of the fracture to determine reliably the location of the highest tissue pressure in a lower extremity when a compartment syndrome is suspected clinically. The highest pressure should be used in the decision-making process.

Adult↗
PubMed1999

Effects of benidipine hydrochloride on 24-hour blood pressure and blood pressure response to mental stress in elderly patients with essential hypertension.

OBJECTIVE: The effects of a new dihydropyridine calcium antagonist, benidipine hydrochloride, on 24-hour blood pressure and blood pressure response to mental arithmetic test were investigated. SUBJECTS: Ten elderly patients with essential hypertension (mean age: 65+/-4 years; 7 male and 3 female). METHOD: After a control period of 4 weeks, 4 mg benidipine was administered once daily in the morning for 12 weeks. Ambulatory blood pressure was monitored using a non-invasive automatic portable device with the cuff-oscillometric method at the end of both the control and treatment periods. RESULTS: Benidipine administration significantly decreased 24-hour blood pressure, while little change was noted in heart rate. Daytime blood pressure decreased significantly, from 148.2+/-11.5/90.8+/-8.8 to 133.8+/-9.2/82.5+/-10.8 mmHg. However, no significant decrease in nighttime diastolic blood pressure was noted, and the decrease in nighttime systolic blood pressure was small (from 129.8+/-9.9/77.1+/-7.6 to 121.8+/-10.1/74.7+/-9.1 mmHg). No significant changes were observed in diurnal variability of blood pressure and heart rate. The decrease in systolic blood pressure by benidipine administration showed a significant positive correlation with systolic blood pressure before treatment in the 24-hour and daytime periods. Single cosinor analysis showed that benidipine administration significantly decreased MESOR of both systolic and diastolic blood pressure, without an increase in amplitude. Both systolic and diastolic blood pressure during mental arithmetic test were significantly decreased after treatment with benidipine, and the increase in systolic blood pressure induced by mental arithmetic test was also significantly attenuated. CONCLUSIONS: These findings indicate that administration of benidipine once daily in the morning effectively decreases blood pressure and attenuates blood pressure response to mental stress. Neither reflex tachycardia, deterioration of diurnal blood pressure change, nor excessive lowering of nighttime blood pressure was observed after benidipine administration. It is suggested that benidipine is a potent and long-lasting calcium antagonist which may be useful for the treatment of elderly hypertensive patients with cardiovascular disease.

Administration, Oral↗
PubMedDate not supplied

Significance of blood pressure in infancy. Familial aggregation and predictive effect on later blood pressure.

Blood pressure was measured in 730 infants and their mothers within 5 days of birth. Paternal blood pressures were obtained where possible, and follow-up measurements were made on participants at 1 week and 1, 6, 12, 18, and 24 months. Infant blood pressures were adjusted for such variables as age, observer, cuff size, and sleep/activity status. Infant blood pressure correlated with maternal blood pressure corrected for age and observer shortly after birth (r = 0.138, p less than 0.001 for systolic pressure; r = 0.169, p less than 0.001 for diastolic pressure). Father-infant correlations were significant only at 1 month after birth (r = 0.179, p = 0.031; r = 0.250, p = 0.002 for systolic and diastolic pressures respectively), and sibling correlations were significant from 6 months after birth (r = 0.173, p = 0.011 for systolic pressure; r = 0.265, p less than 0.001 for diastolic pressure). Blood pressures of infants before 6 months after birth were not consistently predictive of later pressures, but systolic and diastolic blood pressures 6 and 12 months after birth were significantly and positively related to pressures at later ages (for systolic pressures at 6 and 12 months, r = 0.147, p = 0.003; 6 and 18 months, r = 0.218, p less than 0.001; 6 and 24 months, r = 0.212, p less than 0.001). These results indicate that the familial aggregation of blood pressure and blood pressure tracking can be detected early in life.

Adult↗
PubMed2002

Pulmonary venous pressure: relationship to pulmonary artery, pulmonary wedge, and left atrial pressure in normal, lightly sedated dogs.

Because pulmonary venous pressure has never been measured, it is unclear whether pulmonary wedge pressure measures left atrial pressure, as commonly assumed, or pressure more upstream in the pulmonary venous or capillary beds. Fluid-filled mean pulmonary artery and pulmonary wedge pressure were compared with pulmonary venous and left atrial pressure obtained with high-fidelity micromanometer catheters in eight lightly sedated dogs over a physiologic range of filling pressures. In all conditions, mean pulmonary wedge pressure was virtually identical (r = 0.99) to mean left atrial pressure (slope = 0.99; intercept = -0.46 mm Hg). At the same time, mean pulmonary venous pressure (17.1 +/- 6.5 mm Hg) was intermediate between mean pulmonary artery pressure (20.2 +/- 6.2 mm Hg) and mean pulmonary wedge pressure (13.3 +/- 6.2 mm Hg; P < 0.0001) or mean left atrial pressure (13.4 +/- 6.3 mm Hg; P < 0.0001). These relationships were maintained over normal and increased pressure ranges. As measured by conventional flow-directed pulmonary catheters, mean pulmonary wedge pressure accurately reflects left atrial pressure in lightly sedated, spontaneously breathing normal dogs.

Animals↗
PubMed2002

Ambulatory blood pressure after therapeutic and subtherapeutic nasal continuous positive airway pressure for obstructive sleep apnoea: a randomised parallel trial.

BACKGROUND: Obstructive sleep apnoea is associated with raised blood pressure. If blood pressure can be reduced by nasal continuous positive airway pressure (nCPAP), such treatment could reduce risk of cardiovascular disease in patients with obstructive sleep apnoea. Our aim was to see whether nCPAP for sleep apnoea reduces blood pressure compared with the most robust control intervention subtherapeutic nCPAP. METHODS: We did a randomised parallel trial to compare change in blood pressure in 118 men with obstructive sleep apnoea (Epworth score > 9, and a > 4% oxygen desaturation index of > 10 per h) who were assigned to either therapeutic (n=59) or subtherapeutic (59) nCPAP (about 1 cm H(2)O pressure) for 1 month. The primary outcome was the change in 24-h mean blood pressure. Secondary outcomes were changes in systolic, diastolic, sleep, and wake blood pressure, and relations between blood pressure changes, baseline blood pressure, and severity of sleep apnoea. FINDINGS: Therapeutic nCPAP reduced mean arterial ambulatory blood pressure by 2.5 mm Hg (SE 0.8), whereas subtherapeutic nCPAP increased blood pressure by 0.8 mm Hg (0.7) (difference -3.3 [95% CI -5.3 to -1.3]; p=0.0013, unpaired t test). This benefit was seen in both systolic and diastolic blood pressure, and during both sleep and wake. The benefit was larger in patients with more severe sleep apnoea than those who had less severe apnoea, but was independent of the baseline blood pressure. The benefit was especially large in patients taking drug treatment for blood pressure. INTERPRETATION: In patients with most severe sleep apnoea, nCPAP reduces blood pressure, providing significant vascular risk benefits, and substantially improving excessive daytime sleepiness and quality of life.

Adult↗