The Effect of Lower-Body Blood Flow Restriction on Static and Perturbated Stable Stand in Young, Healthy Adults

Muscular fatigue can affect postural control processes by impacting on the neuromuscular and somatosensory system. It is assumed that this leads to an increased risk of injury, especially in sports such as alpine skiing that expose the body to strong and rapidly changing external forces. In this context, posture constraints and contraction-related muscular pressure may lead to muscular deoxygenation. This study investigates whether these constraints and pressure affect static and dynamic postural control. To simulate impaired blood flow in sports within a laboratory task, oxygen saturation was manipulated locally by using an inflatable cuff to induce blood flow restriction (BFR). Twenty-three subjects were asked to stand on a perturbatable platform used to assess postural-related movements. Using a 2 × 2 within-subject design, each participant performed postural control tasks both with and without BFR. BFR resulted in lower oxygenation of the m. quadriceps femoris (p = 0.024) and was associated with a significantly lower time to exhaustion (TTE) compared to the non-restricted condition [F(1,19) = 16.22, p < 0.001, ηp2 = 0.46]. Perturbation resulted in a significantly increased TTE [F(1,19) = 7.28, p = 0.014, ηp2 = 0.277]. There were no significant effects on static and dynamic postural control within the saturation conditions. The present data indicate that BFR conditions leads to deoxygenation and a reduced TTE. Postural control and the ability to regain stability after perturbation were not affected within this investigation.

A Digital Pressure Meter Equipped with Pressure Leak Detection

A manual sphygmomanometer is an instrument used to measure blood pressure, and consists of an inflatable cuff, a mercury manometer (or aneroid gauge) and an inflation ball and gauge. To assess the condition, accuracy and safety of mercury and anaeroid sphygmomanometers in use in general practice and to pilot a scheme for sphyg- momanometer maintenance within the district. Therefore, it must be calibrated periodically. Using the MPX 5050GP sensor as a positive pressure sensor. Requires a maximum pressure of 300 mmHg. This tool is also equipped with a SD Card as external storage. The display used in this module is TFT Nextion 2.8”. After conductings measurements of the three comparisons consisting of Multifunction, DPM and mercury tensimeter to 6 times, the smallest result 0 mmHg and the largest results 251.52 mmHg. While the error in mercury tensimeter’s of leak test to module and rigel is 0.56% and 0.404%.

El tiempo de tránsito del pulso detecta cambios en la presión arterial en respuesta a estimulación eléctrica vestibular y cambio de postura

The interaction of the vestibular organs with the cardiovascular system is a relevant research field with clinical applications that contribute to the understanding of cardiovascular modulation due to movement and posture. The current noninvasive measurement of blood pressure (BP) consists of an inflatable cuff that is unsuitable to perform movement tasks. However, Pulse-Transit Time (PTT), an indirect method that estimates BP from electrocardiographic (ECG) and photoplethysmographic (PPG) recordings, may detect BP variations during dynamic experiments. Galvanic vestibular stimulation (GVS) is considered an analog to mechanical stimulation. Research with GVS has been done involving static and dynamic tasks. Our study aims to determine if PTT is a suitable method to be included in GVS experiments to detect BP modulation. PTT was calculated from 16 healthy subjects during GVS; stimulation was applied while seated and standing. PTT increased during the stimulation period in both positions. The increase was statistically significant only for subjects standing. These findings are following previous GVS studies that monitor BP invasively in animal models. As we expected, an increase in PTT during GVS was observed. Additionally, the increase was slightly different for subjects seated and standing. Overall, results indicate that PTT is an effective method to estimate transient BP changes during GVS.

Cuffless systolic and diastolic blood pressure estimation at the wrist via an optical device: comparison to intra-arterial measurements

The diagnosis and management of hypertension usually requires the estimation of blood pressure (BP) by means of an inflatable cuff. This procedure generates discomfort and limits patient compliance. Cuffless devices capture BP readings without performing any arterial occlusion. We believe that comfortable and cuffless BP monitoring devices can significantly aid in the fight against hypertension and support the expansion of ambulatory and remote patient monitoring programs, provided that these devices provide reliable BP readings. The purpose of this study was to compare the systolic (S) and diastolic (D) blood pressure (BP) estimations from a new optical device at the wrist (figure) against invasive measurements performed on patients scheduled for radial arterial catheterization. The first results from this study were recently published and demonstrated good agreement for the overall study population. Here we report expanded statistical analyses for different population subgroups such as gender, age, body mass index (BMI) and skin color. The study protocol consisted of the simultaneous recording of reflective photo-plethysmographic signals (PPG) from the optical device, and BP values recorded by a contralateral radial arterial catheter. The PPG signals were processed to generate estimates of SBP and DBP. Agreement of paired BP estimations was further calculated in terms of standard deviation (SD) of differences. The mean of differences were systematically zero because BP estimations from the optical device were calibrated for each patient. The table shows that, for the overall population, both SBP and DBP differences SDs were smaller than 8 mmHg (as already published). Furthermore, across different population groups, both genders, all BMIs and all skin colors also resulted in SDs smaller than 8 mmHg. Only patients whose age was above 65 years were associated with a higher SD. For the overall population and most subgroups the new optical technique appears to be capable of replacing more traditional methods of BP estimation. Only the SBP differences for the subgroup of older patients were larger. Additional studies are needed to confirm and expand these very encouraging results. Table 1. SD of measured BP differences Population N SD of SBP differences SD of DBP differences (mmHg) (mmHg) All 16 7.1 2.9 Gender Male 10 6.4 2.8 Female 6 8.0 3.1 Age (years) <65 7 4.0 2.3 >65 9 *9.3 3.4 BMI (kg/m2) <26 10 7.9 2.9 >26 6 5.7 2.8 Skin Color (Fitzpatrick) 2 13 7.7 3.0 3 3 4.5 2.6 *Only subgroup with a SD larger than 8mmHg. Figure 1. The investigational device Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Aktiia SA

Surgical treatment of refractory incontinence in the bitch

Urinary incontinence is a common condition in spayed, female dogs with a reported prevalence between 3.1% and 20.1%. In the majority of dogs with acquired urinary incontinence, urethral sphincter mechanism incompetence is the underlying cause. Approximately 15% of bitches that initially respond to medical therapy ultimately become refractory. Surgical intervention is indicated when patients do not respond or become refractory to medical treatment. Based on the current literature, placement of an artificial urethral sphincter, i.e. an inflatable cuff around the proximal urethra connected to a subcutaneous injection port, provides a very reliable and longterm incontinence resolution in bitches and has a low complication rate.

Estimation of Non-invasive Cuff-less Blood Pressure Using the Photoplethysmogram Signal

Background: This article presents a novel technique relating to the advancement of non-invasive cuff less blood pressure measurement using the PhotoPlethysmoGram (PPG) signals. The morphological characteristics of PPG signal have a strong correlation with the cardiovascular parameters and blood flow. The exact distinguishing feature of the PhotoPlethysmoGram signals is such as height as well as width of the pulse has considered into count for the measurement of blood pressure. In comparison to the existing measurement system like inflatable cuff and electrocardiogram units, this system only requires a pulse plethysomogram unit. The traditional blood pressure unit has many disadvantages such as expert personal, depends on the ability of the person to detect the korotkoff sounds, provides discomfort to the user and is not suitable for long time measurements. Moreover, this is very perceptive to artifacts owing to the existence of cuff. The PAT, PTT of the existing non-invasive techniques need many number of factors for estimation of blood pressure and are highly complex. Results: This method has intended for estimating the cardiovascular parameter of a non-invasive cuff-less blood pressure by utilizing the method of linear regression from PhotoPlethysmoGraphy signal. The real data has obtained using the GUI LabVIEW and further mathematical modelling of the obtained signal has performed by analysis using MATLAB tools. The obtained results had revealed that this technique is simple, non-invasive, cost-effective and consistent for estimating the arterial pulse signal in connection to variation in the amplitude of the waves. The exact distinguished feature of the PhotoPlethysmoGraphy signals like height and width of the pulse, which had considered into the count up for the measurement of blood pressure. The results obtained have been cross validating during the existing blood pressure monitors. Conclusions: The simulated output reveals the height of the pulse (systolic height) is inversely proportional to the systolic blood pressure as well as it rises for increasing cardiac output, however it occurs in less span of time. The pulse width and area is directly proportional to the systolic blood pressure. Our simulation result shows the specific relation between PPG and blood pressure. Error percentages as per the calculation among the extracted features have been less for inflection height ranging from ±10 to a min of ± 2.

Adjacent Channel Interference Modeling of Single Vibration Point on Multichannel Dynamic Pressure Sensors

Pulse waves of a radial artery under different pressures applied through a cuff play an important role in disease diagnosis, especially in traditional chinese medicine (TCM). Pulse waves could be collected by a pressure sensor array affixed to an inflatable cuff. During a process of collecting pulse waves, one sensor of a sensor array moves up and down when the sensor is shocked by a pulse wave. Movement of the sensor leads to the passive displacement of other nearby sensors because of a connecting structure between them. Then, vibration signals will be generated by the nearby sensors although these sensors do not receive radial artery pulse waves. These vibration signals considered an interference are usually superimposed on real signals obtained from these nearby sensors and degrade signal quality. The problem mentioned above does not only generally exist in a pressure sensor array attached to a wristband but also is easy to ignore. This paper proposes a novel interference suppression algorithm based on Welch’s method for estimating and weakening adjacent sensor channel interference to overcome the problem. At first, a sensor array attached to an inflatable cuff and a vibration generator is proposed to establish an experimental platform for simplifying the pulse wave collection process. Then, the interference suppression algorithm is proposed according to mechanical analysis and Welch’s method based on the proposed sensor array and vibration generator. Next anti-interference abilities of the algorithm based on a simplified process are evaluated by different vibration frequencies and applied pressures. The anti-interference abilities of the algorithm based on pulse waves of the radial artery are evaluated indirectly. The results show that the novel interference suppression algorithm could weaken adjacent sensor channel interference and upgrade the signal quality.

Assessment of complications following use of pneumatic tourniquet for elective orthopedic procedures at National Orthopedic Hospital, Enugu

<p class="abstract"><strong>Background:</strong> A pneumatic tourniquet is a constricting or compressing device with an inflatable cuff used to control venous or arterial circulation to an extremity for a period of time. Tourniquet safety is related to the cuff pressure and duration of application. The objective of this study was to determine the common complications that follow the use of pneumatic tourniquet in elective orthopaedic surgical procedures at National Orthopaedic Hospital Enugu.</p><p class="abstract"><strong>Methods:</strong> This was a prospective study over 18 month period (June 2014 – November 2015) at National Orthopaedic Hospital, Enugu. Following ethical approval and written informed consent, patients who met the inclusion criteria were consecutively recruited. The study was conducted using the ‘intelligent pneumatic tourniquet’<strong><em> </em></strong>with single bladder reusable cylindrical cuff. The cuff pressure was determined in each case by addition of 100mmHg to the baseline systolic BP for the upper limbs and 150 mmHg to the baseline systolic BP for the lower limbs. The data collected included patients’ demographics, cuff pressure, cuff location, tourniquet duration and complication encountered among other parameters.</p><p class="abstract"><strong>Results: </strong>A total of 160 procedures in 152 patients were included and analyzed using SPSS version 20.0. The prevalence rate of 1.9% for nerve palsy, 1.3% for tourniquet pain, 1.9% for surgical site infection and 5.6% for pressure sore were found in the study. No other complication was encountered.</p><p class="abstract"><strong>Conclusions:</strong> From the results of this study, it is concluded that the use of pneumatic tourniquet under the prescribed conditions is associated with low prevalence of complications.</p>