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17 recordsLinked to original sources
PubMed1979

Vaginal photoplethysmography: methodological considerations.

Methodological considerations related to the use of vaginal photoplethysmography in the experimental investigation of physiological sexual arousal in women are discussed. Specific topics covered include the operation and use of the device, methods of data reduction and analysis, and the role of vaginal photoplethysmography in the study of female sexual arousal. A review of the literature focusing on methodological issues is also included.

Arousal↗
PubMed1979

Results of ophthalmosonometry and supraorbital photoplethysmography in evaluating carotid arterial stenoses.

A total of 263 patients underwent either periorbital ophthalmosonometry (Doppler ultrasound) or a combination of ophthalmosonometry and supraorbital photoplethysmography (SOPPG) to determine the presence or absence of a hemodynamically significant lesion (occlusion or greater than 50% reduction in lumen diameter). There were 522 vessels studied with Doppler ultrasound and 272 vessels with a combination of the two modalities. The tests were correlated with carotid arteriography to determine their accuracy. Overall accuracy of the Doppler ultrasound examination was 95%. A normal Doppler ultrasound examination was obtained in 367 vessels and arteriography confirmed the absence of a hemodynamically significant lesion in 93%. Of 155 vessels with an abnormal Doppler examination, 149 (96%) were proven on arteriography to have hemodynamically significant lesions. The Doppler ultrasound examination had a high incidence of false-negative examinations (26%) in those vessels that were between 50% and 99% stenotic, however. The SOPPG alone had a high incidence of false-positive examinations (19%); however, in 155 vessels with a normal SOPPG, 98% were proved to have no hemodynamically significant lesion. The combination of Doppler ultrasound and SOPPG was highly accurate in identifying patients with hemodynamically significant lesions. Of 97 vessels with such lesions, 96 (99%) had either an abnormal Doppler ultrasound examination or an abnormal SOPPG. In 240 vessels with concordant results of the Doppler ultrasound and SOPPG, the presence or absence of a hemodynamically significant lesion was accurately predicted in 235 (98%).

Arterial Occlusive Diseases↗
PubMedDate not supplied

The role of photoplethysmography in the prediction of the experimental flap survival.

A standard photoplethysmography, modified to differentiate between arterial and venous vasculature in skin tissue, has been used to measure arterial supply in 100 unipedicle skin flap in 25 pigs. A datum transform from a light intensity scale to a relative arterial blood density scale has been introduced and empirically labeled the vascular coefficient (VC). Statistical analysis of the VC data shows a significant difference between necrotic and surviving flap group mean data as early as 24 hours. Additional analysis in which a normal ogive was fitted to the sample VC data distributions suggests that statistically significant predictions of the probability of eventral flap necrosis can be made using VC measurements obtained immediately postoperatively. It is concluded that the modified photoplethysmograph, in conjunction with the VC data transform constitutes a usable measuring technique for skin flap viability prediction in the experimental animal.

Animals↗
PubMed1979

[Diagnostic and therapy-assessing studies of gingival capillary function by photoplethysmography (preliminary report)].

In the sense of relation pathology, the local peripheral blood supply plays a decisive role also in periodontal diseases. Thus, the differentiation of local circulatory disturbances is of great importance in diagnosis and early detection as well as in therapeutical decisions. Photoplethysmography is well suited for this purpose, especially in evaluating the curves by determining the time of inclination and the plateau index (if necessary, with resort to the nitrangin test). The indicated method also permits to assess the success of therapeutical measures.

Capillaries↗
PubMed1979

The use of photoplethysmography in the assessment of venous insufficiency: a comparison to venous pressure measurements.

In an attempt to develop a noninvasive test to assess objectively the magnitude of venous valvular dysfunction in pathologic states, photoplethysmography (PPG) was compared to venous pressure in the saphenous vein at the ankle. Simultaneous venous pressure and PPG recordings were taken before, during, and after exercise with subjects in the sitting position. In a total of 338 paired measurements in 24 normal, 25 postphlebitic, and 14 varicose limbs, PPG and venous pressure tracings appeared to be identical; data points had a correlation coefficient of great significance (r = 0.898). Postexercise recovery times clearly separated the normal from the postphlebitic limbs. Varicose limbs were assessed accurately regarding results of proposed surgery using an above-knee tourniquet. It appears that the PPG evaluation provides information comparable to venous pressure studies and does so more quickly and noninvasively. The test holds promise in measuring results of direct venous reconstructive surgery as well as in venectomy procedures.

Humans↗
PubMed1979

Assessment of the healing potentials of ulcers of the skin by photoplethysmography.

An objective method of assessing the healing potentials of skin ulcers would eliminate the long waiting period necessary for visual evidence of healing or nonhealing to appear. This would permit the continued conservative treatment for healing ulcers and prompt surgical interventions for those ulcers which are nonhealing. In this preliminary study, the cutaneous blood flow immediately around the ulcer site was studied using the photoplethysmograph. Vigorous cutaneous blood flow shown by good pulsatile wave forms on the photoplethysmograph is shown to be indicative of an ongoing healing process in which spontaneous healing of the ulcer can be predicted. Ulcers with nonpulsatile wave forms fail to heal with conservative management. One patient with nonpulsatile wave forms at the ulcer site showed improvement and eventual healing of the ulcer after undergoing a lumbar sympathectomy. Thus, nonpulsatile blood flow shown by poor wave forms on the photoplethysmograph would suggest early surgical intervention. This method may also aid in determining the extent of surgical excision of the ischemic scar tissue surrounding the chronic skin ulcer.

Humans↗
PubMedDate not supplied

Photoplethysmography in the prediction of experimental flap survival.

A standard photoplethysmograph, modified to differentiate between arterial and venous vasculature in skin tissue, has been used to measure arterial supply in 100 unipedicle skin flaps in 25 pigs. A datum transform from a light intensity scale to a relative arterial blood density scale has been introduced and empirically labelled the vascular coefficient (VC). Statistical analysis of the VC data shows a significant difference between necrotic and surviving flap group mean data as early as 24 hours. Additional analysis in which a normal ogive was fitted to the sample VC data distributions suggests that statistically significant predictions of the probability of eventual flap necrosis can be made using VC measurements obtained immediately postoperatively. It is concluded that the modified photoplethysmograph in conjunction with the VC data transform, constitutes a usable measuring technique for skin flap viability prediction in the experimental animal.

Animals↗
PubMed2026

Home-Based Cardiac Rehabilitation Using a Smart Ring and Telephone Counselling: A Randomized Controlled Trial.

BACKGROUND: Home-based cardiac rehabilitation (HB-CR) is a promising alternative to center-based cardiac rehabilitation as it can address several barriers impeding CR implementation because of its enhanced accessibility. However, to date, HB-CR has not garnered adequate attention due to a lack of communication between patients and medical staff. In this study, we aimed to investigate the effectiveness of HB-CR by monitoring the pulse rate (PR) using a smart ring equipped with photoplethysmography. METHODS: Patients with cardiovascular disease were educated on structured HB-CR methods following a symptom-limited cardiopulmonary exercise test (CPET), and were instructed to wear the device during the exercise session. The recorded PR was uploaded to a website via a smartphone and monitored by medical staff. Patients were randomly assigned to one of two groups: intervention or control group. The intervention group received weekly telephone counselling and was encouraged to maintain optimal levels of physical activity. In contrast, the control group only recorded their exercise data without additional interventions. After 3 months of training, the CPET was performed. RESULTS: Among the 64 randomized patients (32 in each group), an intention-to-treat analysis showed that peak oxygen consumption increased over time in both the groups, with a significantly greater improvement in the intervention group. The group-by-time interaction for peak oxygen consumption was statistically significant (estimated mean difference, 2.0 mL/kg/min; 95% confidence interval, 0.7-3.3; P = 0.004). CONCLUSION: HB-CR using a smart device was effective in improving oxygen consumption. However, appropriate monitoring and timely counselling by medical professionals are important for improved outcomes. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0005893.

Humans↗
PubMed1979

Women's sexual arousal concurrently assessed by three genital measures.

The relationship among three objective measures of genital vasocongestion in women was evaluated both during and after an erotic film using simultaneous recording of both vaginal pressure pulse and vaginal blood volume responses by means of photoplethysmography and of labial temperature change by means of a thermistor clip. During the film each of the genital measures increased for most subjects, resulting in highly significant positive correlations between measures. However, following the erotic film presentation there was considerably less direct correspondence among the three measures; although the genital reactions of most subjects subsided to some extent following the film, none of the three measures consistently returned to prestimulation levels. Periodic estimates of subjective levels of sexual arousal were significantly correlated with each of the genital measures during the erotic film but were not significantly correlated with any after the film.

Adult↗
PubMed1979

Noninvasive monitoring of vascular compromise in trauma.

Many types of trauma may lead to vascular compromise unless treated effectively and promptly. In addition to direct trauma to a major vessel are the crushing injuries, fractures, and burn injuries which give rise to an ischemia-edema cycle and subsequent muscle necrosis and tissue loss. Objective adjuncts to clinical impressions, such as isotope clearance muscle blood flow or the ultrasound Doppler flowmeter are generally not suitable for continuous, uninterrupted monitoring of the degree of vascular compromise. A technique that appears promising in this respect is that of photoplethysmography. This technique uses a small LED infrared emitter/detector array. Blood volume changes in an illuminated vascular bed produce variations in the amount of reflected light sensed by the detector, which after appropriate electronic amplification results in pulsatile blood flow (if present) and its change with time being displayed on the monitor. This technique was used with 25 trauma patients with good results, avoiding unnecessary compartmental decompression in some cases. It has proved to be a simple technique that requires little or no training for interpretation, provides continuous monitoring, is noninvasive and atraumatic in nature, is portable for easy set-up, and is relatively inexpensive.

Blood Circulation↗
PubMed2026

Endothelial function in relation to low-level chronic residential air pollution in a general population: a cohort study.

BACKGROUND: Given the recently updated clean-air targets, this population study assessed endothelial function at low exposure to particulate matter with an aerodynamic diameter of &#x2264;10&#xa0;&#xb5;m (PM10) and &#x2264;2.5&#x2009;&#xb5;m (PM2.5), nitrogen dioxide (NO2) and black carbon (BC). METHODS: In 453 Flemish participants (47.7% women; mean age, 52.8&#x2009;years), endothelial function was assessed by finger photoplethysmography after 5&#x2009;min of ischaemia. The outcome measures were the maximal ischaemic-to-control ratio (Rmax) and the maximal difference (Dmax) in pulse amplitude between the test and control fingers. The air pollutants were related to Rmax and Dmax using mixed models accounting for coresidence, to cardiovascular endpoints by proportional hazards regression, and to residential address by high-resolution spatiotemporal interpolation. RESULTS: From 2010 to 2015, PM10, PM2.5, NO2 and BC decreased (p&#x2009;<&#x2009;0.0001) with 6-year levels averaging 15.9, 12.8, 14.3 and 1.04&#xa0;&#xb5;g/m3. Irrespective of adjustment for risk factors, Dmax was inversely correlated with PM2.5, while associations of Rmax with PM2.5 and associations of both Dmax and Rmax with other pollutants were weaker (p values <0.10), but consistently inverse. Association sizes of Rmax and Dmax with PM10 and PM2.5 weakened over 6&#xa0;years, paralleling the decreasing air pollutants (p&#x2009;&#x2264;&#x2009;0.044). In adjusted analyses, the risk of a composite cardiovascular endpoint decreased (p&#x2009;&#x2264;&#x2009;0.043) with higher Rmax and Dmax with hazard ratios ranging from 0.31 to 0.49. Finally, in the geographical analysis, endothelial dysfunction followed the spatial gradients in PM2.5. CONCLUSIONS: Long-term low-level air pollution is associated with subclinical endothelial dysfunction, the initial and critical step leading to adverse cardiovascular outcomes.

Humans↗
PubMed1979

A photoplethysmographic technique for detecting vascular compromise: a preliminary report.

We have developed a photoplethysmographic technique for monitoring early signs of vascular compromise in extremities affected by direct vessel trauma, crushing trauma, or circumferential burns. The technique consists of positioning a small infrared emitter-detector array shielded from room light over a nailbed of the affected extremity and connecting the array to standard electronic monitoring equipment, thus producing a pulse tracing very similar in contour to an arterial pressure wave. In normal volunteers, simultaneous observations of the tracing and studies of muscle blood flow using Xe133 clearance showed correspondence of disappearance of the plethysmographic signal with limb-threatening levels of ischemia produced by inflation of a blood-pressure cuff. Studies comparing this technique to compartment pressures and arterial flow determined by ultrasound Doppler measurement are continuing. Clinically, we have used this monitoring technique on 29 trauma patients thus far, including 18 with circumferential full-thickness burns of at least one extremity. We believe that these preliminary studies suggest that photoplethysmography is a valuable continuous monitor of vascular status following trauma and a reliable indicator of nutritional blood flow.

Blood Vessels↗
PubMed1979

Cold sensitivity of the hand in arterial occlusive disease.

Digital blood pressure was measured using photoplethysmography in patients with cold sensitivity of the hand. In 19 patients with Buerger's disease, or arteriosclerosis obliterans (arterial occlusion group), 90 of 91 fingers with cold sensitivity showed significantly low pressures. In 17 patients with typical Raynaud's phenomena due either to primary Raynaud's disease or secondary to collagen disease (Raynaud's group), decreased digital pressure was noted in only five of 123 fingers with cold sensitivity. Blood pressure measurements in the fingers after local cooling of the hand showed a more severe response to cold in the Raynaud group than in the arterial occlusion group. These results indicate that the pathophysiologic mechanism for cold sensitivity in arterial occlusive disease is different from that in Raynaud's disease. In the arterial occlusion group impaired circulation due to occlusions in the digital arteries or more proximal arteries is a necessary precondition for cold sensitivity, and an increased sympathetic response to cold is of less importance as an etiologic factor. Thus a patient with cold sensitivity of the hand and normal digital blood pressure should not be considered to have arterial occlusive disease as the underlying cause of cold sensitivity.

Adult↗