Pilot study of comparability of a smartphone blood pressure monitoring algorithm to conventional cuff-based blood pressure measurements

Background/Introduction

There is a growing market for smartphone applications (apps), offering medical assessments such as blood pressure measurements (BPM). These apps have the potential to improve blood pressure (BP) control by making BPM broadly and easily accessible. Yet, to be suitable for clinical and diagnostic purposes, BPM measured with smartphone apps need to be comparable to conventional BPM.

Purpose

We sought to compare a novel photoplethysmographic BPM algorithm used in a smartphone app to conventional cuff-based BPM.

Methods

We included consecutive patients with an indication for ambulatory BPM. Office blood pressure measurements (OBPM) were taken with an oscillometric cuff-based device (Welch Allyn SureBP). The algorithm of the smartphone app detects the pulse wave in finger capillaries using the phone's camera and estimates BP based on the form of the pulse wave. Before estimating a BP value, the algorithm performs a quality assessment to automatically reject recordings with insufficient quality. On the first day (D1), we took 6 OBPM alternating with 5 smartphone BPM (TestBP). On the second day (D2), 4 OBPM alternating with 3 TestBP were measured. TestBP calibrated based on the first OBPM of D1. Each TestBP was then compared to its RefBP (defined as mean of the previous and following OBPM).

Results

50 patients were included in the study, resulting in 50 TestBP values on D1 and 33 on D2. There was no difference at the 5% significance level between the TestBP and RefBP distributions on both days, and for both systolic and diastolic pressures. The mean ± standard deviation (SD) of the differences between TestBP and RefBP was 0.7±9.4 / 1.0±4.5 mmHg on D1 and 2.6±8.2 / 1.3±4.1 mmHg on D2 for systolic/diastolic values, respectively. The number of TestBP measurements within 5, 10 and 15 mmHg from RefBP are shown in Table 1. Bland-Altman plots depicting the agreement between TestBP and RefBP are shown in Figure 1.

Conclusion

This smartphone algorithm shows comparable values to oscillometric cuff-based especially diastolic values. Its differences between TestBP – RefBP have a good stability 1 day after calibration. Before clinical use, this algorithm needs to undergo formal validation against a reference BP method accepted by international standards (auscultatory or invasive methods).

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Centre Suisse d'Electronique et de Microtechnique Table 1Figure 1

Determinants of bone damage: An ex-vivo study on porcine vertebrae

Bone's resistance to fracture depends on several factors, such as bone mass, microarchitecture, and tissue material properties. The clinical assessment of bone strength is generally performed by Dual-X Ray Photon Absorptiometry (DXA), measuring bone mineral density (BMD) and trabecular bone score (TBS). Although it is considered the major predictor of bone strength, BMD only accounts for about 70% of fragility fractures, while the remaining 30% could be described by bone "quality" impairment parameters, mainly related to tissue microarchitecture. The assessment of bone microarchitecture generally requires more invasive techniques, which are not applicable in routine clinical practice, or X-Ray based imaging techniques, requiring a longer post-processing. Another important aspect is the presence of local damage in the bony tissue that may also affect the prediction of bone strength and fracture risk. To provide a more comprehensive analysis of bone quality and quantity, and to assess the effect of damage, here we adopt a framework that includes clinical, morphological, and mechanical analyses, carried out by means of DXA, μCT and mechanical compressive testing, respectively. This study has been carried out on trabecular bones, taken from porcine trabecular vertebrae, for the similarity with human lumbar spine. This study confirms that no single method can provide a complete characterization of bone tissue, and the combination of complementary characterization techniques is required for an accurate and exhaustive description of bone status. BMD and TBS have shown to be complementary parameters to assess bone strength, the former assessing the bone quantity and resistance to damage, and the latter the bone quality and the presence of damage accumulation without being able to predict the risk of fracture.

Impact of reduced mass of light commercial vehicles on fuel consumption, CO2 emissions, air quality, and socio-economic costs

This study presents a modelling system to evaluate the impact of weight reduction in light commercial vehicles with diesel engines on air quality and greenhouse gas emissions. The PROPS model assesses the emissions of one vehicle in the aforementioned category and its corresponding reduced-weight version. The results serve as an input to the RIAT+ tool, an air quality integrated assessment modelling system. This paper applies the tools in a case study in the Lombardy region (Italy) and discusses the input data pre-processing, the PROPS-RIAT+ modelling system runs, and the results.

Electromagnetic disturbances rejection with single skin contact in the context of ECG measurements with cooperative sensors

Classical approaches to make high-quality measurements of biopotential signals require the use of shielded or multi-wire cables connecting the electrodes to a central unit in a star arrangement. Consequently, increasing the number of leads increases cabling and connector complexity which is not only limiting patient comfort but also anticipated as the main limiting factor for future miniaturization and cost reduction of tomorrow's wearables. We have recently introduced a novel sensing architecture that significantly reduces cabling complexity by eliminating shielded or multi-wire cables as well as by allowing simple connectors thanks to a bus arrangement. In this architecture, electrodes are replaced by so-called cooperative sensors. However, in this design, one of the cooperative sensors needs to be equipped with two contacts with the skin for proper common mode rejection, thus making its miniaturization problematic. This paper presents a novel common mode rejection principle which overcomes this limitation. When compared to others, the suggested approach is advantageous as it keeps the cabling complexity to its minimum. First measurements demonstrated in a real-life scenario the feasibility of this common mode rejection principle for a wearable 12-lead electrocardiogram monitoring system.

Cooperative dry-electrode sensors for multi-lead biopotential and bioimpedance monitoring

Cooperative sensors is a novel measurement architecture that allows the acquiring of biopotential signals on patients in a comfortable and easy-to-integrate manner. The novel sensors are defined as cooperative in the sense that at least two of them work in concert to measure a target physiological signal, such as a multi-lead electrocardiogram or a thoracic bioimpedance.This paper starts by analysing the state-of-the-art methods to simultaneously measure biopotential and bioimpedance signals, and justifies why currently (1) passive electrodes require the use of shielded or double-shielded cables, and (2) active electrodes require the use of multi-wired cabled technologies, when aiming at high quality physiological measurements.In order to overcome the limitations of the state-of-the-art, a new method for biopotential and bioimpedance measurement using the cooperative sensor is then presented. The novel architecture allows the acquisition of the aforementioned biosignals without the need of shielded or multi-wire cables by splitting the electronics into separate electronic sensors comprising each of two electrodes, one for voltage measurement and one for current injection. The sensors are directly in contact with the skin and connected together by only one unshielded wire. This new configuration requires one power supply per sensor and all sensors need to be synchronized together to allow them to work in concert.After presenting the working principle of the cooperative sensor architecture, this paper reports first experimental results on the use of the technology when applied to measuring multi-lead ECG signals on patients. Measurements performed on a healthy patient demonstrate the feasibility of using this novel cooperative sensor architecture to measure biopotential signals and compliance with common mode rejection specification accordingly to international standard (IEC 60601-2-47) has also been assessed.By reducing the need of using complex wiring setups, and by eliminating the presence of central recording devices (cooperative sensors directly sense and store the measured biosignals on the site), the depicted novel technology is a candidate to a novel generation of highly-integrated, comfortable and reliable technologies that measure physiological signals in real-life scenarios.

Quantitative 3D evaluation of step ascent and descent in individuals with Down syndrome--analysis of a daily challenging task

BACKGROUND

Step ascent and descent can perturb stability increasing the incidence of falls, especially in older individuals with functional limitations and intellectual disabilities, such as those with Down syndrome (DS). The aim of this study was to investigate the biomechanics and motor coordination of step ascent and descent in adults with DS and compare them with a group of healthy individuals, considering movement kinematics and kinetics.

METHOD

Fourteen adults with DS and 12 similarly aged adults without DS who were free of known motor problems were quantitatively assessed during ascending and descending a step using an optoelectronic system (BTS SMART-D), force platforms and video recording. Kinematic and kinetic parameters were identified and calculated for each study participant and comparisons were made between the DS and a control group (CG).

RESULTS

Despite similar age ranges, subjects in the DS group performed the step ascent and descent movements slower, with longer duration and with a more accentuated range of motion of the trunk and of the ankle joint than those in the CG. Additionally, the double stance phase on the step was substantially longer in the DS group when represented as a percentage of the entire stepping sequence (ascent, double stance on the step and descent). In terms of kinetics, ground force platform data revealed that the DS subjects showed higher instability in the medio-lateral direction during double support phase than similarly aged CG subjects and cannot be attributed to age-associated changes in stability.

CONCLUSIONS

These findings help to elucidate the complex biomechanical strategy of people with DS during a step ascent and descent movement task and may have a major role in the multidimensional evaluation and tailored management for them.

Quantifying established clinical assessment measures using 3D-movement analysis in individuals with Down syndrome

PURPOSE

A movement protocol for quantifying functional limitation in people with Down syndrome (DS) during the execution of a series of range of motion (ROM) tasks has been developed as a new assessment approach, combining quantitative measures of movement analysis and functional mobility with clinically established qualitative motor skill assessments.

METHODS

Fifteen subjects with DS and 11 subjects with typical development were evaluated using this movement protocol.

RESULTS

The results revealed longer durations in execution across all tasks in the DS group and were most likely due to low muscular tone and poor coordination. A significant difference in ankle ROM was found in the DS group during leg-lifting, with a wide plantar-flexion demonstrated during the entire movement. This result may be associated with the typical strategy for foot contact that generally favours the toe. Significant differences were also found in the trunk ROM and in the knee ROM and may likely reflect an increase of agonist-antagonist co-contraction, a strategy that may modify stability and dynamic equilibrium.

CONCLUSION

The combined quantitative/qualitative protocol is an important advancement in evaluating individuals with DS and should be integrated into a more comprehensive evaluation of dynamic gait and lower limb analysis.

[Mohs micrographic surgery for the treatment of basal cell carcinoma]

INTRODUCTION

Basal cell carcinoma accounts for 75% of all nonmelanoma skin cancer. Although various treatment modalities are available, the most frequently used option is surgical excision. Here, we evaluate the efficacy of Mohs micrographic surgery for the treatment of basal cell carcinoma.

MATERIAL AND METHODS

A retrospective review of cases of basal cell carcinoma treated with Mohs micrographic surgery between October 2003 and June 2009 was performed using patient records from Hospital Italiano in Buenos Aires, Argentina.

RESULTS

A total of 2412 basal cell carcinomas treated with Mohs micrographic surgery were identified; 50.5% were in women and 49.5% in men. The mean age of the patients was 70.7 years (range, 8-100 years). The histologic type of the tumor was solid in 65.3% of cases and in 89% of cases the tumor was located on the head or neck. Ten percent of the tumors were recurrent following previous treatment. A mean of 1.74 Mohs stages were used, with a mean of 3.81 sections. The mean size of the initial defect was 0.86 cm² and the mean final defect was 1.88 cm². The ratio of initial tumor size to final defect was estimated at 1.02. Over a mean follow-up of 32 months, there were 9 cases of tumor recurrence (0.37%).

CONCLUSIONS

In our experience, Mohs micrographic surgery is effective for the treatment of high-risk basal cell carcinoma.

In vitro toxicity of naphthalene, 1-naphthol, 2-naphthol and 1,4-naphthoquinone on human CFU-GM from female and male cord blood donors

In animal models, naphthalene toxicity has been studied in different target organs and has been shown to be gender-dependent and metabolism related. In humans, it is readily absorbed and is metabolised by several cytochrome P450's. Naphthalene and its metabolites can cross the placental barrier and consequently may affect foetal tissues. The aim of this study was to compare the in vitro toxicity of naphthalene and its metabolites, 1-naphthol, 2-naphthol and 1,4-naphthoquinone, on human haematopoietic foetal progenitors (CFU-GM) derived from newborn male and female donors. The mRNA expression of Cyp1A2 and Cyp3A4 was also evaluated. Naphthalene did not affect CFU-GM proliferation, while 1-naphthol, 2-naphthol and particularly 1,4-naphthoquinone strongly inhibited the clonogenicity of progenitors, from both male and female donors. mRNA of Cyp1A2 and Cyp3A4 was not expressed neither at the basal level, nor after naphthalene treatment, while treatment with 1,4-naphthoquinone induced expression of both enzymes in both genders, with Cyp1A2 being expressed four times more than Cyp3A4. Female CFU-GM was significantly more sensitive to 1,4-naphthoquinone than male and after treatment both enzymes were expressed twice as much as in the male precursors. These results suggest that a gender-specific 1,4-naphthoquinone metabolic pathway may exist, which gives rise to unknown toxic metabolites.

A facile stereoselective synthesis of α-glycosyl ureas

Alpha-glycosyl ureas can be synthesised directly from tetra-O-benzyl glycosyl azides and isocyanates, using a one-pot procedure that is simple and general in scope. The benzyl protecting groups are easily removed from the urea products by catalytic hydrogenation. The synthesised alpha-glycosyl ureas represent a new class of neo-glycoconjugates with the potential of being resistant towards carbohydrate processing enzymes.

[Helmet delivered CPAP for in-patients]

The scanty availability of intensive care beds in our hospital, compared with the needings of the area, led us to employ surgical department beds as post-intensive beds. The possibility of delivering non invasive ventilation by head helmet allowed, also in such settings, the ventilation of patients. This paper analyses the main capacities and problems that are faced by the nurse in the management of head helmet delivered CPAP. Main systems for gas delivery that can be used in the departments, PEEP application modalities and psychologic management of the patient are detailed.

Genetic diversity of GBV-C/HGV strains among HIV infected-IVDU and blood donors from Buenos Aires, Argentina

GBV-C/HGV RNA was investigated in serum samples from 70 HIV(+) intravenous drug users (IVDU), as well as from 200 blood donors from Buenos Aires, Argentina. Viral RNA was demonstrated in 21 IVDU by reverse transcription-nested PCR of the 5' UTR. c-DNA amplified products were analyzed and their sequences compared with those downloaded from GenBank. A phylogenetic tree based on 171 sequences demonstrated the presence of three major genogroups, including two subgroups, within local samples, i.e. group 1 (n=1), 2a (n=11), 2b (n=4) and 3 (n=5). These results agreed entirely with those obtained by a novel RFLP (J. Clin. Microbiol. 37, 1340-1347, 1999) of the same 5' UTR amplicons. As expected, GBV-C/HGV RNA prevalence was significantly higher among IVDU than among blood donors (P<0.0001), although within the latter group an unexpectedly high rate was also detected, since 11 of 200 sera (5.5%) proved positive. These viral isolates were ascribed either to subgroup 2a (n=5), subgroup 2b (n=5) or genogroup 3 (n=1). Briefly, this partial view of GBV-C/HGV molecular epidemiology in Argentina shows: (i) different rates of GBV-C/HGV infection within both IVDU and blood donors; (ii) a high prevalence of viral RNA among blood donors; and (iii) a predominant circulation of genogroup 2, with minor contribution of groups 3 and 1.

GB virus C/hepatitis G virus groups and subgroups: classification by a restriction fragment length polymorphism method based on phylogenetic analysis of the 5' untranslated region

A phylogenetic tree based on 150 5' untranslated region sequences deposited in GenBank database allowed segregation of the sequences into three major groups, including two subgroups, i.e., 1, 2a, 2b, and 3, supported by bootstrap analysis. Restriction site analysis of these sequences predicted that HinfI and either AatII or AciI could be used for genomic typing with 99.4% accuracy. cDNA sequencing and subsequent alignment of 21 Argentine GB virus C/hepatitis G virus strains confirmed restriction fragment length polymorphism patterns theoretically predicted. This method may be useful for a rapid screening of samples when either epidemiological or transmission studies of this agent are carried out.

[Study of human papillomavirus via chemiluminescence technic and polymerase chain reaction in transitional cell carcinoma of the bladder]

INTRODUCTION

The exact ethiology of bladder carcinoma isn't yet known; an implication of human papillomavirus (HPV) has been recently hypothesized.

MATERIALS AND METHODS

In this study HPV-DNA was investigated in urethral secretion and in bladder carcinoma of 37 patients. The analysis was performed by in vitro hybridization (chemiluminescent assay) and Polymerase Chain Reaction in order to detect HPV 6, 11, 16, 18, 31, 33 through specific primers.

RESULTS

On 3 out of 37 patients (8.1%) we found the presence of HPV-DNA, only in bladder T.U.R. and not in the corresponding urethral swab.

CONCLUSIONS

Our data suggest that human papillomavirus is unlikely to be involved in the pathogenesis of transitional cell carcinoma, in agreement with most European and American research groups.

Fine needle aspiration biopsy of hepatocellular carcinoma resembling neuroendocrine tumor. A case report

BACKGROUND

The incidence of hepatocellular carcinoma (HCC) is steadily increasing in western countries. Its present incidence in Italy is about 6.9/100,000. The diagnosis is usually made by a combination of ultrasound (US), computed tomography (CT) and fine needle aspiration biopsy (FNAB). HCC resembling a neuroendocrine tumor has been described, but no previous FNAB diagnosis was reported.

CASE

An asymptomatic 45-year-old man underwent a CT scan after incidental US detection of multiple focal lesions in both lobes of the liver. FNAB showed clusters of small neoplastic cells with hyperchromatic nuclei and scanty cytoplasm. A thin tissue core showed a microacinar pattern very similar to that of a neuroendocrine tumor. A large panel of specific antibodies displayed an immunophenotype consistent with HCC.

CONCLUSION

In this rare variant of HCC, the final diagnosis could be assessed only by correlating the cytologic, microhistologic and immunohistochemical features.

[Cystic papillary tumors of the pancreas: 3 new cases]

Three cases of papillary cystic tumor of the pancreas (PCTP) are described. They were observed in two female patients aged 42 and 39, and in a male patient aged 55. A fine-needle ultrasound-guided aspiration biopsy was performed in the man. The cytologic and histologic features turned out to be diagnostic and in compliance with literature data. In the three cases immunohistochemical analyses showed positive reaction to vimentin and alpha-1-antitrypsin. Two cases expressed neuron-specific enolase. Ultrastructural examination revealed similarities between neoplastic cells and normal centroacinar cells of the pancreas. Flow cytometric study revealed a diploid G0/1 peak in two cases. The patients underwent wide surgical excision of the neoplasia. No recurrences or metastases are found with follow-up of 10 years, 8 years and 10 month respectively.

[Prognostic value of cellular ploidy in adenocarcinoma of the middle rectum]

A retrospective study of DNA content in 38 medium-rectal adenocarcinomas (a rectal part between 8 and 12 cm. from anus) was performed using flow cytometry in order to find probable correlations among ploidy, grading, staging and survival in patients who had undergone a surgical operation from January 1975 to December 1989. At the beginning of the work, 21 patients were alive and 17 were dead. Histologically 15 carcinomas (39.4%) were G1, 22 (57.8%) were G2 and only 1 (2.6%) was G3. Moreover 1 case (2.6%) was pT1, 7 (18.4%) were pT2 and 30 (78.9%) were pT3. 11 adenocarcinomas (29%) were euploid and 27 (71%) were aneuploid. These percentages agree with literature data. 11 of dead patients (64.7%) had aneuploid neoplasias and 6 (35.3%) diploid; 16 of alive patients (72.2%) had aneuploid carcinomas and 5 (23.8%) diploid. The difference of survival between aneuploid and diploid carcinomas isn't statistically significative (X2 = 0.168 ns). No correlation was found among aneuploidy, grading and staging, probably on account of small number of analyzed cases, owing to particular and little rectal part included in the study. Likely, having a larger case number we'll be able to obtain more incisive informations from this type of analysis in the next future.

[Planning of a prospective study with a biological bank]

This present work aims to give a critical description of the organization and operative aspects of project ORDET (prospective study on diet and hormones in the aetiology of breast cancer). A number of problems which could arise when carrying-out a prospective study are described: they concern participant recruitment, laboratory organization, planning of a biological bank plus relative security checks in order to ensure full workability and personnel standardization in questionnaire administration and anthropometrical measurements. The methods adopted by ORDET, or at least some of them, could be useful for those engaged in the planning phase of a similarly designed project using a biological bank.