Dexmedetomidine inhibits gastric emptying and oro-caecal transit in healthy volunteers.

BACKGROUND: Dexmedetomidine is a potent and selective α2-adrenoceptor agonist used for perioperative and intensive care sedation with certain beneficial qualities. However, based on preclinical observations, it might inhibit gastric emptying and gastrointestinal transit, which could result in unwanted effects in intensive care patients. This study evaluated the effects of dexmedetomidine on gastric emptying and oro-caecal transit time in healthy volunteers. METHODS: Twelve healthy male subjects were given 1 µg kg(-1) of dexmedetomidine i.v. over 20 min followed by a continuous i.v. infusion of 0.7 µg kg(-1) h(-1) for 190 min. For comparison, subjects were also given 0.10 mg kg(-1) of morphine hydrochloride i.v. over 20 min and a placebo infusion in a randomized order. Gastric emptying was assessed with the paracetamol absorption test and oro-caecal transit time with the hydrogen breath test. RESULTS: The time to maximum paracetamol concentration in plasma was significantly longer, maximum paracetamol concentration was significantly lower, the area under the plasma paracetamol concentration-time curve was significantly smaller, and oro-caecal transit time was significantly longer during dexmedetomidine infusion compared with morphine or placebo infusion. CONCLUSIONS: Dexmedetomidine markedly inhibits gastric emptying and gastrointestinal transit in healthy volunteers.

Ambulatory blood pressure characteristics in normotensive and treated hypertensive older people.

The objective of this study was to determine the normal values and characteristics of 24-h ambulatory blood pressure (ABP) and to describe the ABP level of treated hypertensive subjects in an older Finnish population. ABP was measured in 502 randomly selected subjects aged 64 years or over living in a Finnish municipality (mean age 70 years, range 64-87 years). A total of 211 subjects did not have blood pressure (BP) affecting medication. ABP measurements were taken every 30 min for 24 h, and the day- and night-time periods were diary-based. The results were that in untreated subjects, the average office BP was 134/82 +/- 16/9 (s.d.) mm Hg for men and 140/81 +/- 18/8 mm Hg for women. The 24-h average BP was 120/75 +/- 14/8 mm Hg (95th percentile upper limit 145/93 mm Hg) for men and 125/75 +/- 15/7 (95th = 154/89 mm Hg) for women. The daytime averages were 127/78 +/- 12/7 mm Hg (95th = 154/99 mm Hg) and 131/78 +/- 15/7 mm Hg (95th = 158/91 mm Hg) for men and women, respectively. The ABP daytime value of 130/83 mm Hg corresponded best to the office BP value of 140/90 mm Hg. All BP values were significantly higher in the treated hypertensive group compared to the normotensive group. Night-time BP was markedly lower than daytime BP, and no difference in circadian variability was found between the normotensive and hypertensive subjects. Both office and ambulatory BPs were significantly higher in women than in men. This study provides sex-specific normal values for ABP in a 64 to 87-year-old age group. The normal values of ABP were markedly lower than the office BP values. Hypertensives, even when treated, tended to have elevated values.

Ambulatory blood pressure and left ventricular mass in older age.

BACKGROUND: The purpose of this study was to analyse the association of ambulatory blood pressure (ABP) to left ventricular mass (LVM) in a population aged over 64 years and to describe the level of ABP in subjects with and without left ventricular hypertrophy (LVH) in older age. METHODS: ABP measurement and echocardiography for calculation of LVM were assessed in 490 inhabitants (mean age 70.7 years, range 64-87 years) of a small town in southwestern Finland who were able to visit an outpatient clinic. Explanatory factors associated with LVM were assessed with linear regression analysis. LVH was defined as calculated LVM-index values exceeding 150 g/m2 in men and 120 g/m2 in women adopted from the Framingham Study. RESULTS: Systolic ABP was significantly associated with LVM. No correlation between diastolic ABP and LVM was found. Other factors independently related to LVM were gender, body mass index and age. The prevalence of echocardiographic LVH was 22%. Subjects with LVH had markedly higher systolic ABP levels than those without LVH (mean (SD) 24-h ABP: 132(16)/75(8) mmHg vs. 123(13)/75(8) mmHg). CONCLUSION: Systolic ABP is associated with LVM in older people. In addition, systolic ABP is superior to diastolic ABP in relation to LVM in the aged.

Long-term reproducibility of ambulatory blood pressure in unselected elderly subjects.

The aim of this study was to evaluate the long-term reproducibility and validity of 24-h ambulatory blood pressure measurements (ABPM) in an unselected elderly population. In a rural Finnish community 503 randomly chosen invited persons over 65 years of age participated and went through 24-h ABPM. As part of the validation of the methodology, the reproducibility study was conducted in 26 persons (age 65-76 years). Two identical sets of measurement were performed at 4-12 (median 8) month intervals. The agreement between measurements was assessed by correlation coefficients and standard deviation (SD) of the differences. There were no significant differences in 24-h, daytime and night-time average diastolic blood pressure (DBP) and daytime average systolic blood pressure (SBP) between the two measurements. During the second measurement, 24-h SBP and night-time average SBP were slightly higher than those obtained by the first monitoring. Average 24-h SBP and DBP were 18 and 7 mmHg lower, respectively, than office blood pressure averages. The correlation coefficients were significantly higher for 24-h ambulatory blood pressure than for office blood pressure. The SD of the mean difference between visits was significantly lower for 24-h ambulatory blood pressure than for office blood pressure measurements. These findings show that the long-term reproducibility of ambulatory blood pressure is good in an elderly unselected population and better than the office blood pressure reproducibility.

Ambulatory blood pressure reproducibility and application of the method in a healthy Finnish cohort.

The aim of the present study has been to study the reproducibility, validity and normal values of ambulatory blood pressure measurement in a healthy Finnish cohort. The reproducibility of ambulatory blood pressure monitoring was examined in healthy volunteers and normal values were determined in a Finnish cohort of males and women of different ages. In the reproducibility study the recording was repeated at 2-week intervals. In the validity study simultaneous measurements were done manually with a mercury sphygmomanometer and compared with the measurement by the ambulatory blood pressure recording unit, both connected with the cuff by a T-tube; this study included 100 consecutive measurements in a patient group. A relatively small cohort was taken from the normal value study group. In addition to ambulatory blood pressure their left ventricle mass was also determined by echocardiography. The correlation between manual blood pressure measurement and simultaneous measurement by the ambulatory blood pressure unit was 0.98. In the reproducibility study the correlations between the two 24-h measurements 2 weeks apart were also good. Depending on the parameter (daytime, nighttime or 24-h blood pressure mean, systolic or diastolic values) the correlation coefficient varied between 0.81 and 0.91. Thus both systolic and diastolic blood pressures, whether expressed as 24-h averages and daytime or nighttime averages, correlated well between these two recording sessions. The data obtained in the present Finnish cohort were well within the published reference value limits, showing only fairly modest age-dependence appearing at quite an old age. There was no significant correlation between the left ventricle mass and ambulatory blood pressure values in a population having normal blood pressure. The results suggest good intra-individual correlation and reproducibility in ambulatory blood pressure monitoring, suggesting this method to be useful in the monitoring of individual blood pressure levels. The validity of the method is good and the published reference values can be applied with reasonable reliability in different populations. In an adult population with normal blood pressure, no correlation between left ventricle mass and blood pressure values can be found, suggesting this correlation may first appear in cohorts including persons with elevated blood pressure values.