Nurse effects on measurement error in household biosocial surveys.

BACKGROUND: Biosocial survey data are in high demand, yet little is known about the measurement quality of health measures collected by nurses in respondents' homes. Our objective was to analyze the degree to which nurses influence measurement in anthropometric and physical performance indicators collected from respondents in two nationally-representative UK biosocial surveys. METHODS: The English Longitudinal Survey of Ageing and the UK Household Longitudinal Study - Understanding Society were used to analyze fourteen anthropometric and physical performance measures covering weight, height, pulse, grip strength, and lung capacity. Cross-classified multilevel models were used to estimate "nurse effects" on measurement error. RESULTS: Overall, there is a medium effect of nurses on measurement. Across all measures collected in both studies, nurses explain around 13% of all measurement variation. Variation in specific measures range between approximately 2 and 25%. Grip strength and lung capacity are more heavily influenced by nurses than are height, weight, and pulse. Lastly, nurse characteristics explain only a very small proportion of nurse measurement variation. CONCLUSION: Objective health measures collected by nurses in household biosocial surveys are susceptible to non-trivial amounts of measurement variation. Nurse ID numbers should be regularly included in biosocial data releases to allow researchers to account for this unnecessary source of variation. Further, researchers are advised to conduct sensitivity analyses using control variables that account for nurse variation to confirm whether their substantive findings are influenced by nurse measurement effects.

On detection of spontaneous pulse by photoplethysmography in cardiopulmonary resuscitation.

OBJECTIVE: This work investigates the potential of photoplethysmography (PPG) to detect a spontaneous pulse from the finger, nose or ear in order to support pulse checks during cardiopulmonary resuscitation (CPR). METHODS: In a prospective single-center cross-sectional study, PPG signals were acquired from cardiac arrest victims who underwent CPR. The PPG signals were analyzed and compared to arterial blood pressure (ABP) signals as a reference during three distranaisco; Date: 2/2/2020; Time:18:44:23inct phases of CPR: compression pauses, on-going compressions and at very low arterial blood pressure. Data analysis was based on a qualitative subjective visual description of similarities of the frequency content of PPG and ABP waveform. RESULTS: In 9 patients PPG waveforms corresponded to ABP waveforms during normal blood pressures. During ABP in the clinically challenging range of 60 to 90 mmHg and during chest compressions and pauses, PPG continued to resemble ABP, as both signals showed similar frequency components as a result of chest compressions as well as cardiac activity. Altogether 1199 s of PPG data in compression pauses were expected to show a spontaneous pulse, of which 732 s (61%) of data were artifact-free and showed the spontaneous pulse as visible in the ABP. CONCLUSIONS: PPG signals at all investigated sites can indicate pulse presence at the moment the heart resumes beating as verified via the ABP signal. Therefore, PPG may provide decision support during CPR, especially related to preventing and shortening interruptions for unnecessary pulse checks. This could have impact on CPR outcome and should further be investigated.

Comparison of pulse contour, aortic Doppler ultrasound and bioelectrical impedance estimates of stroke volume during rapid changes in blood pressure.

NEW FINDINGS: What is the central question of this study? Pulse contour analysis of the finger arterial pressure by Windkessel modelling is commonly used to estimate stroke volume continuously. But is it valid during dynamic changes in blood pressure? What is the main finding and its importance? Second-by-second analysis revealed that pulse contour analysis underestimated stroke volume by up to 25% after standing from a squat, and 16% after standing thigh-cuff release, when compared with aortic Doppler ultrasound estimates. These results reveal that pulse contour analysis of stroke volume should be interpreted with caution during rapid changes in physiological state. ABSTRACT: Dynamic measurements of stroke volume (SV) and cardiac output provide an index of central haemodynamics during transitional states, such as postural changes and onset of exercise. The most widely used method to assess dynamic fluctuations in SV is the Modelflow method, which uses the arterial blood pressure waveform along with age- and sex-specific aortic properties to compute beat-to-beat estimates of aortic flow. Modelflow has been validated against more direct methods in steady-state conditions, but not during dynamic changes in physiological state, such as active orthostatic stress testing. In the present study, we compared the dynamic SV responses from Modelflow (SVMF ), aortic Doppler ultrasound (SVU/S ) and bioelectrical impedance analysis (SVBIA ) during two different orthostatic stress tests, a squat-to-stand (S-S) transition and a standing bilateral thigh-cuff release (TCR), in 15 adults (six females). Second-by-second analysis revealed that when compared with estimates of SV by aortic Doppler ultrasound, Modelflow underestimated SV by up to 25% from 3 to 11 s after standing from the squat position and by up to 16% from 3 to 7 s after TCR (P < 0.05). The SVMF and SVBIA were similar during the first minute of the S-S transition, but were different 3 s after TCR and at intermittent time points between 34 and 44 s (P < 0.05). These findings indicate that the physiological conditions elicited by orthostatic stress testing violate some of the inherent assumptions of Modelflow and challenge models used to interpret bioelectrical impedance responses, resulting in an underestimation in SV during rapid changes in physiological state.

The POCUS Pulse Check: A Case Series on a Novel Method for Determining the Presence of a Pulse Using Point-of-Care Ultrasound.

BACKGROUND: During cardiopulmonary resuscitation, pulse checks must be rapid and accurate. Despite the importance placed on the detection of a pulse, several studies have shown that health care providers have poor accuracy for detection of central pulses by palpation. To date, the use of point-of-care ultrasound (POCUS) in cardiac arrest has focused on the presence of cardiac standstill and diagnosing reversible causes of the arrest. OBJECTIVE: This case series highlights a simple, novel approach to determine whether pulses are present or absent by using POCUS compression of the central arteries. DISCUSSION: Using this technique, we found that a POCUS pulse check can be consistently performed in < 5 s and is clearly determinate, even when palpation yields indeterminate results. CONCLUSIONS: In this case series, the POCUS pulse check was a valuable adjunct that helped to change management for critically ill patients. Future prospective studies are required to determine the accuracy of this technique and the impact on patient outcomes in a larger cohort.

The relationship between forearm skin speed-resolved perfusion and oxygen saturation, and finger arterial pulsation amplitudes, as indirect measures of endothelial function.

OBJECTIVE: Endothelial function is important for regulating peripheral blood flow to meet varying metabolic demands and can be measured indirectly during vascular provocations. In this study, we compared the PAT finger response (EndoPAT) after a 5-minutes arterial occlusion to that from forearm skin comprehensive microcirculation analysis (EPOS). METHODS: Measurements in 16 subjects with varying cardiovascular risk factors were carried out concurrently with both methods during arterial occlusion, while forearm skin was also evaluated during local heating. RESULTS: Peak values for EPOS skin Perfconv and speed-resolved total perfusion after the release of the occlusion were significantly correlated to the EndoPAT RHI (ρ = .68, P = .007 and ρ = .60, P = .025, respectively), mainly due to high-speed blood flow. During local heating, EPOS skin oxygen saturation, SO2, was significantly correlated to RHI (ρ = .62, P = .043). This indicates that SO2 may have diagnostic value regarding endothelial function. CONCLUSIONS: We have demonstrated for the first time a significant relationship between forearm skin microcirculatory perfusion and oxygen saturation and finger PAT. Both local heating and reactive hyperemia are useful skin provocations. Further studies are needed to understand the precise regulation mechanisms of blood flow and oxygenation during these tests.

Using the Pulse Contour Method to Measure the Changes in Stroke Volume during a Passive Leg Raising Test.

The pulse contour method is often used with the Windkessel model to measure stroke volume. We used a digital pressure and flow sensors to detect the parameters of the Windkessel model from the pulse waveform. The objective of this study was to assess the stability and accuracy of this method by making use of the passive leg raising test. We studied 24 healthy subjects (40 ± 9.3 years), and used the Medis® CS 1000, an impedance cardiography, as the comparing reference. The pulse contour method measured the waveform of the brachial artery by using a cuff. The compliance and resistance of the peripheral artery was detected from the cuff characteristics and the blood pressure waveform. Then, according to the method proposed by Romano et al., the stroke volume could be measured. This method was implemented in our designed blood pressure monitor. A passive leg raising test, which could immediately change the preloading of the heart, was done to certify the performance of our method. The pulse contour method and impedance cardiography simultaneously measured the stroke volume. The measurement of the changes in stroke volume using the pulse contour method had a very high correlation with the Medis® CS 1000 measurement, the correlation coefficient of the changed ratio and changed differences in stroke volume were r² = 0.712 and r² = 0.709, respectively. It was shown that the stroke volume measured by using the pulse contour method was not accurate enough. But, the changes in the stroke volume could be accurately measured with this pulse contour method. Changes in stroke volume are often used to understand the conditions of cardiac preloading in the clinical field. Moreover, the operation of the pulse contour method is easier than using impedance cardiography and echocardiography. Thus, this method is suitable to use in different healthcare fields.

Systematic screening for the detection of atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF), the most common arrhythmia in clinical practice, is a leading cause of morbidity and mortality. Screening for AF in asymptomatic patients has been proposed as a way of reducing the burden of the disease by detecting people who would benefit from prophylactic anticoagulation therapy before the onset of symptoms. However, for screening to be an effective intervention, it must improve the detection of AF and provide benefit for those detected earlier as a result of screening. OBJECTIVES: This review aims to answer the following questions.Does systematic screening increase the detection of AF compared with routine practice? Which combination of screening population, strategy and test is most effective for detecting AF compared with routine practice? What safety issues and adverse events may be associated with individual screening programmes? How acceptable is the intervention to the target population? What costs are associated with systematic screening for AF? SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and EMBASE (Ovid) up to 11 November 2015. We searched other relevant research databases, trials registries and websites up to December 2015. We also searched reference lists of identified studies for potentially relevant studies, and we contacted corresponding authors for information about additional published or unpublished studies that may be relevant. We applied no language restrictions. SELECTION CRITERIA: Randomised controlled trials comparing screening for AF with routine practice in people 40 years of age and older were eligible. Two review authors (PM and CT) independently selected trials for inclusion. DATA COLLECTION AND ANALYSIS: Two review authors (PM and CT) independently assessed risk of bias and extracted data. We used odds ratios (ORs) and 95% confidence intervals (CIs) to present results for the primary outcome, which is a dichotomous variable. As we identified only one study for inclusion, we performed no meta-analysis. We used the GRADE (Grades of Recommendation, Assessment, Development and Evaluation Working Group) method to assess the quality of the evidence and GRADEPro to create a 'Summary of findings' table. MAIN RESULTS: One cluster-randomised controlled trial met the inclusion criteria for this review. This study compared systematic screening (by invitation to have an electrocardiogram (ECG)) and opportunistic screening (pulse palpation during a general practitioner (GP) consultation for any reason, followed by an ECG if pulse was irregular) versus routine practice (normal case finding on the basis of clinical presentation) in people 65 years of age or older.Results show that both systematic screening and opportunistic screening of people over 65 years of age are more effective than routine practice (OR 1.57, 95% CI 1.08 to 2.26; and OR 1.58, 95% CI 1.10 to 2.29, respectively; both moderate-quality evidence). We found no difference in the effectiveness of systematic screening and opportunistic screening (OR 0.99, 95% CI 0.72 to 1.37; low-quality evidence). A subgroup analysis found that systematic screening and opportunistic screening were more effective in men (OR 2.68, 95% CI 1.51 to 4.76; and OR 2.33, 95% CI 1.29 to 4.19, respectively) than in women (OR 0.98, 95% CI 0.59 to 1.62; and OR 1.2, 95% CI 0.74 to 1.93, respectively). No adverse events associated with screening were reported.The incremental cost per additional case detected by opportunistic screening was GBP 337, compared with GBP 1514 for systematic screening. All cost estimates were based on data from the single included trial, which was conducted in the UK between 2001 and 2003. AUTHORS' CONCLUSIONS: Evidence suggests that systematic screening and opportunistic screening for AF increase the rate of detection of new cases compared with routine practice. Although these approaches have comparable effects on the overall AF diagnosis rate, the cost of systematic screening is significantly greater than the cost of opportunistic screening from the perspective of the health service provider. Few studies have investigated effects of screening in other health systems and in younger age groups; therefore, caution needs to be exercised in relation to transferability of these results beyond the setting and population in which the included study was conducted.Additional research is needed to examine the effectiveness of alternative screening strategies and to investigate the effects of the intervention on risk of stroke for screened versus non-screened populations.

Quantitative assessment of the impact of blood pulsation on images of the pupil in infrared light.

Pulsation in the blood vessels of the eye has a big impact on the dynamics of the entire eyeball and its individual elements. Blood pulsation in the retina can be recorded by the pupil, whose size is also subject to dynamic changes. The study involved synchronous measurements of pupil size using a high-speed camera, and blood pulsation using a pulse oximeter placed on the ear lobe. In addition, there were no metrologically significant differences in the phase shift between the average brightness of the individual pupil quadrants. Blood pulsation in other ocular tissues can affect the dynamics of the optical properties of the eye. As demonstrated in this paper, it affects the pupil behavior and its parameters to a considerable extent.

Risk of stroke or transient ischemic attack after atrial fibrillation ablation with oral anticoagulant use guided by ECG monitoring and pulse assessment.

INTRODUCTION: We sought to gain insight into stroke risk after atrial fibrillation (AF) ablation. METHODS AND RESULTS: We followed 1,990 patients for >1 year (49 ± 29 months) who underwent AF ablation. Prior to stopping oral anticoagulants (OAC), we performed 3-week transtelephonic ECG monitoring (TTM) and taught patients heart rate and pulse assessment. Documented AF or inability to do monitoring or assess pulse precluded stopping OAC in CHADS2 ≥1 patients. OAC was stopped in 546/840 (65%) with CHADS2  = 0; 384/796 (48%) with CHADS2  = 1 and 101/354 (40%) with CHADS2 ≥ 2. Sixteen strokes or TIAs occurred (0.2%/patient-year); 5 in CHADS2  = 0 patients (all off OAC); 5 in CHADS2  = 1 (1 off and 4 on OAC); and 6 in CHADS2 ≥2 (2 off and 4 on OAC). Twelve of 16 patients (75%) with stroke or TIA had documented AF. In patients "off " OAC, stroke rate/year stratified by the CHADS2 score was similar (CHADS2  = 0: 0.28%; CHADS2  = 1: 0.07%; CHADS2 ≥2: 0.50%; P = NS). There was no difference in stroke risk "on" versus "off " OAC in CHADS2  = 1 (0.48% vs. 0.07%) or CHADS2 ≥2 (0.39% vs. 0.50%). Risk of major bleeding per patient year "on" OAC was > "off " OAC (13/1,138 (1.14%) versus 1/832 (0.1%); P<0.016). CONCLUSIONS: Post-AF ablation with OAC guided by TTM and pulse assessment: (1) Overall stroke or TIA rate risk is low and risk is due to recurrent AF and (2) OAC can be stopped in 40% of CHADS2 ≥2 patients with low stroke and hemorrhagic risk.

High-yield nontoxic gene transfer through conjugation of the CM18-Tat11 chimeric peptide with nanosecond electric pulses.

We report a novel nontoxic, high-yield, gene delivery system based on the synergistic use of nanosecond electric pulses (NPs) and nanomolar doses of the recently introduced CM18-Tat11 chimeric peptide (sequence of KWKLFKKIGAVLKVLTTGYGRKKRRQRRR, residues 1-7 of cecropin-A, 2-12 of melittin, and 47-57 of HIV-1 Tat protein). This combined use makes it possible to drastically reduce the required CM18-Tat11 concentration and confines stable nanopore formation to vesicle membranes followed by DNA release, while no detectable perturbation of the plasma membrane is observed. Two different experimental assays are exploited to quantitatively evaluate the details of NPs and CM18-Tat11 cooperation: (i) cytofluorimetric analysis of the integrity of synthetic 1,2-dioleoyl-sn-glycero-3-phosphocholine giant unilamellar vesicles exposed to CM18-Tat11 and NPs and (ii) the in vitro transfection efficiency of a green fluorescent protein-encoding plasmid conjugated to CM18-Tat11 in the presence of NPs. Data support a model in which NPs induce membrane perturbation in the form of transient pores on all cellular membranes, while the peptide stabilizes membrane defects selectively within endosomes. Interestingly, atomistic molecular dynamics simulations show that the latter activity can be specifically attributed to the CM18 module, while Tat11 remains essential for cargo binding and vector subcellular localization. We argue that this result represents a paradigmatic example that can open the way to other targeted delivery protocols.

Perfusion index in newborn infants: a noninvasive tool for neonatal monitoring.

AIM: To review the utility of perfusion index (PI) in the evaluation of neonatal clinical conditions. Twenty-five manuscripts were reviewed. PI provides information about haemodynamic stability, illness severity, early neonatal respiratory outcome, low superior vena cava flow and subclinical chorioamnionitis. CONCLUSION: PI is a valuable tool to assess the newborn's health condition and could become a standardised measure in clinical evaluation. Different study designs are necessary to provide further validation to this method.

Evaluation of a cochlear-implant processing strategy incorporating phantom stimulation and asymmetric pulses.

OBJECTIVE: To evaluate a speech-processing strategy in which the lowest frequency channel is conveyed using an asymmetric pulse shape and "phantom stimulation", where current is injected into one intra-cochlear electrode and where the return current is shared between an intra-cochlear and an extra-cochlear electrode. This strategy is expected to provide more selective excitation of the cochlear apex, compared to a standard strategy where the lowest-frequency channel is conveyed by symmetric pulses in monopolar mode. In both strategies all other channels were conveyed by monopolar stimulation. DESIGN: Within-subjects comparison between the two strategies. Four experiments: (1) discrimination between the strategies, controlling for loudness differences, (2) consonant identification, (3) recognition of lowpass-filtered sentences in quiet, (4) sentence recognition in the presence of a competing speaker. STUDY SAMPLE: Eight users of the Advanced Bionics CII/Hi-Res 90k cochlear implant. RESULTS: Listeners could easily discriminate between the two strategies but no consistent differences in performance were observed. CONCLUSIONS: The proposed method does not improve speech perception, at least in the short term.

The MAIN Shirt: a textile-integrated magnetic induction sensor array.

A system is presented for long-term monitoring of respiration and pulse. It comprises four non-contact sensors based on magnetic eddy current induction that are textile-integrated into a shirt. The sensors are technically characterized by laboratory experiments that investigate the sensitivity and measuring depth, as well as the mutual interaction between adjacent pairs of sensors. The ability of the device to monitor respiration and pulse is demonstrated by measurements in healthy volunteers. The proposed system (called the MAIN (magnetic induction) Shirt) does not need electrodes or any other skin contact. It is wearable, unobtrusive and can easily be integrated into an individual's daily routine. Therefore, the system appears to be a suitable option for long-term monitoring in a domestic environment or any other unsupervised telemonitoring scenario.

Relationship between Renying pulse augmentation index and Cunkou pulse condition in different blood pressure groups.

OBJECTIVE: To explore the relationship between Renying pulse (carotid) augmentation index (AI) and Cunkou pulse condition in different blood pressure groups, and the clinical significance of Renying and Cunkou pulse parameters to reflect vascular function. METHODS: Eighty-six patients with essential hypertension (EH) and 52 individuals with normal blood pressure (control group) between September 2010 and January 2012 were included in this study. Renying pulse AI was examined by a new diagnostic tool (ALOKA ProSound Alpha 10)--wave intensity (WI) that is calculated as the product of the derivatives of the simultaneously recorded blood pressure changes (dP/dt) and blood-flow-velocity changes (dU/dt), while Cunkou pulse condition was detected by DDMX-100 Pulse Apparatus in both EH and control groups. A multifactorial correlation analysis was performed for data analysis. RESULTS: After adjusting for potential confounding variables, in the EH group, AI was positively correlated with t5, w2/t (r(t5) = 0.225, P < 0.05; r(w2/t) = 0.230, P < 0.05) and negatively correlated with h5, h5/h1 and w2 (r(h5) = -0.393, P < 0.01; r(h5)/h1) = -0.444, P < 0.01; r(w2) = -0.389, P < 0.01). In the control group, AI was positively correlated with t3, t4, t5 and w1 (r(t3) = 0.595, P < 0.01; r(t4) = 0.292, P < 0.05; r(t5) = 0.318, P < 0.05; r(w1) = 0.541, P < 0.01) and negatively correlated with h1, h2, h3, Ad and A (r(h1) = -0.368, P < 0.05; r(h2) = -0.330, P < 0.05; r(h3) = -0.327, P < 0.05; rAd = -0.322, P < 0.05; rA = -0.410, P < 0.01). In the total sample group (EH plus control group, n = 138), AI was positively correlated with t, t5, w1 and w2t (r(t) = 0.257, P < 0.01; r(t5) = 0.266, P < 0.01; r(w1) = 0.184, P < 0.05; r(w2/t) = 0.210, P < 0.05) and negatively correlated with h5, h5/h1, w2 and Ad (r(h5) = -0.230, P < 0.01; r(h5/h1) = -0.218, P < 0.05; r(w2) = -0.267, P < 0.01; rAd = -0.246, P < 0.01). Multiple linear regression analysis was carried out to model the relationship (F = 7.887, P < 0.001). CONCLUSION: Renying pulse AI can effectively predict arterial stiffness in synchrony with the manifestations of Cunkou pulse in elderly patients with hypertension. Cunkou pulse apparatus is a valuable tool for evaluating AI in clinical practice. The close correlations reported above reflect the holistic concept of Traditional Chinese Medicine.

Effectiveness of systematic screening for the detection of atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is a leading cause of morbidity and mortality. Screening for AF in asymptomatic patients has been proposed as a way of reducing the burden of the disease by detecting people who would benefit from prophylactic anticoagulation therapy prior to the onset of symptoms. However, for screening to be an effective intervention it must improve the detection of AF and provide benefit for those who are detected earlier as a result of screening. OBJECTIVES: The primary objective of this review was to examine whether screening programmes increase the detection of new cases of AF compared to routine practice. The secondary objectives were to identify which combination of screening strategy and patient population is most effective, as well as assessing any safety issues associated with screening, its acceptability within the target population and the costs involved. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library, MEDLINE (Ovid) and EMBASE (Ovid) up to March 2012. Other relevant research databases, trials registries and websites were searched up to June 2012. Reference lists of identified studies were also searched for potentially relevant studies and we contacted corresponding authors for information about additional published or unpublished studies that may be relevant. No language restrictions were applied. SELECTION CRITERIA: Randomised controlled trials, controlled before and after studies and interrupted time series studies comparing screening for AF with routine practice in people aged 40 years and over were eligible. Two authors (PM, CT or MF) independently selected the trials for inclusion. DATA COLLECTION AND ANALYSIS: Assessment of risk of bias and data extraction were performed independently by two authors (PM, CT). Odds ratios (OR) and 95% confidence intervals (CI) were used to present the results for the primary outcome, which is a dichotomous variable. Since only one included study was identified, no meta-analysis was performed. MAIN RESULTS: One cluster randomised controlled trial met the inclusion criteria for this review. This study compared systematic screening (by invitation to have an electrocardiogram (ECG)) and opportunistic screening (pulse palpation during a general practitioner (GP) consultation for any reason followed by an ECG if pulse was irregular) to routine practice (normal case finding on the basis of clinical presentation) in people aged 65 years or older. The risk of bias in the included study was judged to be low.Both systematic and opportunistic screening of people over the age of 65 years are more effective than routine practice (OR 1.57, 95% CI 1.08 to 2.26 and OR 1.58, 95% CI 1.10 to 2.29, respectively). The number needed to screen in order to detect one additional case compared to routine practice was 172 (95% CI 94 to 927) for systematic screening and 167 (95% CI 92 to 806) for opportunistic screening. Both systematic and opportunistic screening were more effective in men (OR 2.68, 95% CI 1.51 to 4.76 and OR 2.33, 95% CI 1.29 to 4.19, respectively) than in women (OR 0.98, 95% CI 0.59 to 1.62 and OR 1.2, 95% CI 0.74 to 1.93, respectively). No data on the effectiveness of screening in different ethnic or socioeconomic groups were available. There were insufficient data to compare the effectiveness of screening programmes in different healthcare settings.Systematic screening was associated with a better overall uptake rate than opportunistic screening (53% versus 46%) except in the ≥ 75 years age group where uptake rates were similar (43% versus 42%). In both screening programmes men were more likely to participate than women (57% versus 50% in systematic screening, 49% versus 41% in opportunistic screening) and younger people (65 to 74 years) were more likely to participate than people aged 75 years and over (61% versus 43% systematic, 49% versus 42% opportunistic). No adverse events associated with screening were reported.The incremental cost per additional case detected by opportunistic screening was GBP 337, compared to GBP 1514 for systematic screening. All cost estimates were based on data from the single included trial, which was conducted in the UK between 2001 and 2003. AUTHORS' CONCLUSIONS: Systematic and opportunistic screening for AF increase the rate of detection of new cases compared with routine practice. While both approaches have a comparable effect on the overall AF diagnosis rate, the cost of systematic screening is significantly more than that of opportunistic screening from the perspective of the health service provider. The lack of studies investigating the effect of screening in other health systems and younger age groups means that caution needs to be exercised in relation to the transferability of these results beyond the setting and population in which the included study was conducted.Additional research is needed to examine the effectiveness of alternative screening strategies and to investigate the effect of the intervention on the risk of stroke for screened versus non-screened populations.

Validation of noninvasive MOEMS-assisted measurement system based on CCD sensor for radial pulse analysis.

Examination of wrist radial pulse is a noninvasive diagnostic method, which occupies a very important position in Traditional Chinese Medicine. It is based on manual palpation and therefore relies largely on the practitioner's subjective technical skills and judgment. Consequently, it lacks reliability and consistency, which limits practical applications in clinical medicine. Thus, quantifiable characterization of the wrist pulse diagnosis method is a prerequisite for its further development and widespread use. This paper reports application of a noninvasive CCD sensor-based hybrid measurement system for radial pulse signal analysis. First, artery wall deformations caused by the blood flow are calibrated with a laser triangulation displacement sensor, following by the measurement of the deformations with projection moiré method. Different input pressures and fluids of various viscosities are used in the assembled artificial blood flow system in order to test the performance of laser triangulation technique with detection sensitivity enhancement through microfabricated retroreflective optical element placed on a synthetic vascular graft. Subsequently, the applicability of double-exposure whole-field projection moiré technique for registration of blood flow pulses is considered: a computational model and representative example are provided, followed by in vitro experiment performed on a vascular graft with artificial skin atop, which validates the suitability of the technique for characterization of skin surface deformations caused by the radial pulsation.

Influence of periodic heartbeat reversal and abdominal movements on hemocoelic and tracheal pressure in resting blowflies Calliphora vicina.

In Calliphoridae and Drosophilidae, the dorsal vessel (heart and aorta with associated venous channels) is the only connection between the thorax and the abdomen. Hemolymph oscillates between the compartments by periodic heartbeat reversal, but both the mechanism and its influence on hemocoelic and tracheal pressure have remained unclear. The pumping direction of the heart regularly reverses, with a higher pulse rate during backward compared with forward pumping. A sequence of forward and backward pulse periods lasts approximately 34 s. Pulse rate, direction, velocity and the duration of heartbeat periods were determined by thermistor and electrophysiological measurements. For the first time, heartbeat-induced pressure changes were measured in the hemocoel and in the tracheal system of the thorax and the abdomen. The tracheal pressure changed from sub-atmospheric during backward heartbeat to supra-atmospheric during forward heartbeat in the thorax and inversely in the abdomen. The heartbeat reversals were coordinated with slow abdominal movements with a pumping stroke at the beginning of the forward pulse period. The pressure effect of the pumping stroke was visible only in the abdomen. Periodic hemolymph shift and abdominal movements resulted in pressure changes in the hemocoel and tracheal system alternating in the thorax and abdomen, suggesting an effect on respiratory gas exchange.

Use of PC mouse components for continuous measuring of human heartbeat.

A new technology for remote measuring of vibration sources was recently developed for industrial, medical, and security-related applications [Int. Appl. Patent No: PCT/IL2008/001008]. It requires relatively expensive equipment, such as high-speed complementary metal oxide semiconductor (CMOS) sensors and customized optics. In this paper, we demonstrate how the usage of a simple personal computer (PC) mouse as an optical system composed of a low-power laser and a CMOS circuitry on the same integrated circuit package, can be used to monitor heartbeat from the wrist. The method is based on modifying the mouse optical system in such a way that it will recognize temporal change in skin's vibration profile, generated due to the heart pulses, as mouse movement. The tests that were carried out show a very good correlation between the heartbeat rate measured from human skin and the reference values taken manually.

Opportunistic detection of atrial fibrillation in subjects aged 65 years or older in primare care: a randomised clinical trial of efficacy. DOFA-AP study protocol.

BACKGROUND: Clinical Practice Guidelines recommend using peripheral blood pulse measuring as a screening test for Atrial Fibrillation. However, there is no adequate evidence supporting the efficacy of such procedure in primary care clinical practice. This paper describes a study protocol designed to verify whether early opportunistic screening for Atrial Fibrillation by measuring blood pulse is more effective than regular practice in subjects aged 65 years attending primary care centers. METHODS/DESIGN: An cluster-randomized controlled trial conducted in Primary Care Centers of the Spanish National Health Service. A total of 269 physicians and nurses will be allocated to one of the two arms of the trial by stratified randomization with a 3:2 ratio (three practitioners will be assigned to the Control Group for every two practitioners assigned to the Experimental Group). As many as 12 870 patients aged 65 years or older and meeting eligibility criteria will be recruited (8 580 will be allocated to the Experimental Group and 4 290 to the Control Group). Randomization and allocation to trial groups will be carried out by a central computer system. The Experimental Group practitioners will conduct an opportunistic case finding for patients with Atrial Fibrillation, while the Control Group practitioners will follow the regular guidelines. The first step will be finding new Atrial Fibrillation cases. A descriptive inferential analysis will be performed (bivariate and multivariate by multilevel logistic regression analysis). DISCUSSION: If our hypothesis is confirmed, we expect Primary Care professionals to take a more proactive approach and adopt a new protocol when a patient meeting the established screening criteria is identified. Finally, we expect this measure to be incorporated into Clinical Practice Guidelines. TRIAL REGISTRATION: The study is registered as NCT01291953 (ClinicalTrials.gob).

[24-Hour arterial pressure variability and 24-hour variability of pulse carries unidirectional character and is not associated with left ventricular hypertrophy (results of population study)].

Alternative prognostic interpretation of variability of arterial pressure (AP) and pulse seems contradictory if one considers classical conceptions of close physiological connection between AP and pulse. It is logical to expect that elevated variability of AP should be associated with elevated variability of pulse and vice versa. Within framework of the project EPOCH we examined a populational sample of inhabitants of Novosibirsk (129 men and 170 women) formed according to the family principle. Ambulatory 24-hour registration of AP and pulse was carried out with 15-30 minutes interval. Variability of AP turned out to be unidirectionally interconnected with variability of pulse and was not an independent marker of hypertrophy of the left ventricle but was associated with it at the account of concealed dependence on mean 24-hour AP. Cornell voltage index in persons with normal AP, "white coat" arterial hypertension (AH), "masked" AH was comparable and significantly lower than in subjects with sustained AH.