Beat-to-beat measurement of the finger arterial pressure pulse shape index at rest and during exercise

Arterial pressure waveform can be characterized by the pulse shape index kpulse determined as kpulse = (Pmean - Pdiast) / (Psyst - Pdiast). For brachial artery, the shape index value of 0.33 is usually applied to approximate Pmean from the measured Psyst and Pdiast. Our purpose was to test whether this value can validly be applied to finger vascular beds under different experimental conditions. By using Finapres, we non-invasively estimated the beat-to-beat values of kpulse in the fingers of young healthy persons in supine position at rest and during a 4-min moderate exercise (rhythmical exercise with the quadricep muscles in combination with handgrip compression). To detect intensive peripheral vasoconstrictions, a laser-Doppler probe was attached to the thumb pulp of the same hand. Periods of 30 s without intensive vasoconstriction for rest, different stages of exercise and recovery were involved in the analysis in every subject. The results demonstrated that the group-averaged value of kpulse (median with a 95% confidence interval) in the fingers of 11 healthy volunteers aged from 20 to 24, equalled 0.33 (0.31- 0.34), 0.31 (0.28-0.34), 0.35 (0.33-0.39) and 0.38 (0.34-0.43) for rest, first and second stages of exercise and recovery, respectively. We conclude that in the fingers of young healthy persons in supine position formula Pmean = Pdiast + 1/3 (Psyst - Pdiast) gives an adequate approximation for rest and low intensity exercise (first stage), and slightly underestimates the actual finger mean blood pressure during moderate exercise (second stage) and recovery.     

Portapres and differential oscillometric finger blood pressure changes during deep breathing test in the assessment of BRS index

The aim of this study was to investigate changes in the finger blood pressure during a deep breathing test (DB) and to find out whether the mean blood pressure might be used as a substitute for the systolic pressure in calculations of baroreflex sensitivity from data derived from the DB test. Continuous beat-to-beat finger pressure was recorded by the volume clamp method (Portapres model 2 monitor). In addition, the mean arterial pressure was recorded by the modified oscillometric method (UT9201 beat-to-beat monitor, University of Tartu, Estonia). Fifteen healthy volunteers, aged 25-56 years, were studied. The amplitude of respiration-linked oscillations in the Portapres systolic (Psyst) and mean blood pressure (Pmean) was 22.2 +/- 8.8 and 16.6 +/- 5.8 mmHg, respectively. There was no significant difference between the amplitudes of induced changes in Pmean recorded by the two devices: the amplitude of oscillations in the mean blood pressure recorded by the differential oscillometric monitor was 16.0 +/- 5.9 mmHg. The amplitude of oscillations in Psyst correlated significantly with the amplitude of oscillations in Pmean recorded either by Portapres or by UT9201 (r=0.95 and 0.98, respectively). The high correlation between the amplitudes of oscillations in mean and systolic blood pressure allows to conclude that mean arterial pressure changes during a DB test might be used instead of systolic pressure changes in calculation of the ratio of changes in pulse interval to changes in blood pressure, which is considered to reflect baroreflex sensitivity.     

The effects of NG-nitro-L-arginine methyl ester on systolic pressure, diastolic pressure and pulse pressure according to the initial level of blood pressure

The objective of this study was to re-examine whether the effect of the nitric oxide synthesis inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), on blood pressure depends on peripheral vascular tone. The effects of L-NAME (10 mg/kg, i.v.) on diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP) and heart rate (HR) were studied in pithed rats. Sal-pithed rats received 0.9% NaCl, 10 microl/kg/min. Vascular tone was step-wise increased with 3, 10 and 30 microg/kg/min intravenous phenylephrine infusion (LPhe-pithed, MPhe-pithed and HPhe-pithed rats respectively). L-NAME elicited vasopressor responses in all the animals studied. L-NAME increases in SBP and DBP in Sal-pithed rats were significantly smaller than the ones obtained in phenylephrine infused rats. The increases in DBP elicited by L-NAME were greater in LPhe-pithed rats compared with those of MPhe-pithed and HPhe-pithed rats (i.e. the step-wise rises in DBP obtained with phenylephrine were inversely related to the increases in DBP produced by L-NAME); however, the increases in SBP were similar between these experimental groups. The PP increased during L-NAME-induced pressor responses in phenylephrine-infused rats. l-NAME increases in PP showed the following order: Sal-pithed < LPhe-pithed < MPhe-pithed < or = HPhe-pithed rats. HR was not modified by L-NAME. In conclusion, the vasopressor responses produced by L-NAME in pithed rats are influenced by the pre-existing vasomotor tone in complex form. We did not find a simple positive correlation between the vascular tone or level of arterial pressure, and the magnitude of the diastolic and systolic pressor responses elicited by L-NAME. Interestingly, the increase in PP induced by l-NAME was greater in accordance with the increasing value of baseline arterial pressure. NO synthesis inhibition in the arterial endothelium may possibly explain the increase in PP caused by L-NAME, as resulting from the reduction in proximal conduit artery compliance.     

Influence of arterial wave reflection on carotid blood pressure and intima‐media thickness in older endurance trained men and women with pre‐hypertension

Increased carotid intima‐media thickness (IMT) with aging is a significant predictor of mortality. Older endurance trained (ET) individuals have lower carotid artery stiffness but similar carotid IMT when compared to sedentary (SED) age‐matched peers. The purpose of this study was to examine the contribution of arterial wave reflections to carotid hemodynamics and IMT in older ET and SED with pre‐hypertension. Subjects consisted of endurance‐trained master athletes and age‐matched sedentary controls (mean age 67 years). Carotid artery Beta‐stiffness index and IMT was assessed with ultrasonography. Carotid pressure and augmented pressure from wave reflections (obtained from pulse contour analysis) was measured with applanation tonometry. Carotid systolic blood pressure (SBP) and IMT were not different between groups (P>0·05). Carotid stiffness was significantly lower in ET versus SED (7·3 ± 0·8 versus 9·9 ± 0·6, P<0·05). Augmented pressure was significantly greater in ET versus SED (17·7 ± 1·6 versus 13·3 ± 1·5 mmHg, P<0·05). When adjusting for differences in resting heart rate, there were no group differences in augmented pressure. In conclusion, older ET persons with pre‐hypertension have reduced carotid artery stiffness, but similar carotid SBP and carotid IMT when compared to SED. The lack of change in carotid SBP and IMT in older ET may be related to the inability of chronic exercise training to reduce bradycardia‐related augmented pressure from wave reflections with aging.     

Comparison of the effects of bimatoprost and timolol on intraocular pressure and pulsatile ocular blood flow in patients with primary open-angle glaucoma: A prospective, open-label, randomized, two-arm, parallel-group study

Abstract

Background:

The current objective of antiglaucomatous therapy is to reduce intraocular pressure (IOP), and thus to preserve visual function. Many ophthalmologists believe this objective is best achieved by methods that improve ocular blood flow to the optic nerve head. Beta-blockers are effective ocular hypotensive agents, but they can reduce choroidal blood flow. Bimatoprost, a new prostamide analogue, has been shown to have a better IOP-lowering effect compared with the nonselective beta-adrenergic receptor blocker timolol maleate, but little is known about its effects on the vascular bed of the eye.

Objective:

The aim of this study was to compare the effects of bimatoprost and timolol on IOP and choroidal blood flow (as measured using pulsatile ocular blood flow [pOBF]) in patients with primary open-angle glaucoma (POAG).

Methods:

This prospective, open-label, randomized, 2-arm, parallel-group study was conducted at the Glaucoma Research Centre, Department of Ophthalmology, University Hospital of Bari, Bari, Italy. Patients with POAG having well-controlled IOP (<16 mm Hg) on monotherapy with timolol 0.5% ophthalmic solution (2 drops per affected eye BID) for ≥12 months but with a progressive decrease in pOBF during the same time period were randomly allocated to 1 of 2 treatment groups. One group continued monotherapy with timolol, 2 drops per affected eye BID. The other group was switched (without washout) to bimatoprost 0.3% ophthalmic solution (2 drops per affected eye QD [9 pm]). Treatment was given for 180 days. IOP and pOBF were assessed at the diagnostic visit (pre-timolol), baseline (day 0), and treatment days 15, 30, 60, 90, and 180. Primary adverse effects (AEs) (ie, conjunctival hyperemia, conjunctival papillae, stinging, burning, foreign body sensation, and pigmentation of periorbital skin) were monitored throughout the study.

Results:

Thirty-eight patients were enrolled (22 men, 16 women; mean [SD] age, 51.7 [4.8] years; 19 patients per treatment group; 38 eligible eyes). At 180-day follow-up in the timolol group, the IOP and the pOBF remained unchanged compared with baseline. In the bimatoprost group the IOP remained unchanged and the pOBF was decreased by 38.9% compared with baseline (P < 0.01). All AEs were mild to moderate and included conjunctival hyperemia and ocular itching (5 patients [26.3%] in the bimatoprost group) and pigmentation of periorbital skin (2 patients [40.0%] in the bimatoprost group). The incidence of each AE was higher in the bimatoprost group than in the timolol group (P = 0.008).

Conclusions:

In this population of patients with POAG, bimatoprost was associated with increased pOBF, and the reduction in pOBF associated with timolol was corrected after patients were switched to bimatoprost. Bimatoprost was associated with increased choroidal blood flow, beyond the levels recorded before timolol treatment. The decreased IOP level achieved in the timolol group seemed to be improved further by bimatoprost. Considering the potential efficacy of bimatoprost on IOP and pOBF, we suggest that this new drug may represent a clinical advance in the medical treatment of POAG.Key words: bimatoprost, timolol, pulsatile ocular blood flow, intraocular pressure, primary open-angle glaucoma     

Music as a nursing intervention: effects of music listening on blood pressure, heart rate, and respiratory rate in abdominal surgery patients

Contradictory results have been presented on how music listening affects patients' blood pressure, heart rate, and respiratory rate. The aim of the present study was to evaluate the effects of music listening on blood pressure, heart rate, and respiratory rate on operation day, and on the first, second, and third postoperative days in abdominal surgery patients. Using a quasi-experimental pretest-post-test design, 168 abdominal surgery patients were assigned every second week to the music group (n=83) or to the control group (n=85) for 25 months. In the music group, the respiratory rate was significantly lower after intervention on both the first and second postoperative days compared with the control group. A significant reduction in systolic blood pressure was demonstrated in the group that received music compared with the control group on both the first and second postoperative days. Evaluation of the long-term effects of music on physiological factors showed that the respiratory rate in the music group was significantly lower compared with the control group. Nurses should offer music listening to surgery patients because of its potential benefit.     

Effects of travoprost eye drops on intraocular pressure and pulsatile ocular blood flow: a 180-day, randomized, double-masked comparison with latanoprost eye drops in patients with open-angle glaucoma

Background: Because of the increasing realization of the importance of optic nerve head perfusion in the pathogenesis of glaucoma, the influence of new antiglaucomatous drugs on ocular hemodynamic properties should be investigated.Objective: The aim of this study was to compare the effects of 2 prostaglandin analogues, travoprost eye drops and latanoprost eye drops, on intraocular pressure (IOP) and pulsatile ocular blood flow (pOBF) in patients with primary open-angle glaucoma (POAG).Methods: Previously untreated patients aged 40 to 60 years with POAG and normal brachial blood pressure (BBP), heart rate, body mass index, and hemorheologic findings were eligible for this randomized, double-masked study. Two drops of travoprost (group T) or latanoprost (group L) were self-administered in both eyes at 9:00 pm. In all patients, IOP, pOBF, BBP, and heart rate were measured at baseline and on days 15, 30, 60, 90, and 180 of treatment.Results: Twenty-five consecutive patients with POAG were enrolled in this study conducted at the Glaucoma Research Center of the Department of Ophthalmology, Bari University, Policlinico di Bari (Bari, Italy). Of these, 7 were withdrawn because they did not return for the second appointment, leaving 18 patients (11 men, 7 women; mean [SD] age, 51.9 [5.5] years) to complete the study. In both groups, mean IOP values were significantly reduced at all time points compared with baseline (all P<0.01). Mean pOBF values increased ∼50% from baseline following treatment with either travoprost or latanoprost by day 15, were maintained at that level for 60 days, and then gradually decreased (group T: P = NS, NS, <0.01, <0.05, and <0.05 at days 15, 30, 60, 90, and 180, respectively, vs baseline; group L: P<0.01 at all time points vs baseline). All other parameters remained constant throughout the study. An early inverse correlation between IOP and pOBF was noted in group T but not in group L. No significant differences were found between groups in IOP or pOBF at any time point.Conclusions: In this study population, pOBF was increased with travoprost and latanoprost in the short term, but this effect was kept constant only with travoprost. IOP was reduced with both drugs after short-term therapy, and this reduction was maintained in both groups. Travoprost may represent another option for the medical treatment of POAG.