Noninvasive monitoring of intra-abdominal pressure by measuring abdominal wall tension

BACKGROUND: Noninvasive monitoring of intra-abdominal pressure(IAP) by measuring abdominal wall tension(AWT) was effective and feasible in previous postmortem and animal studies. This study aimed to investigate the feasibility of the AWT method for noninvasively monitoring IAP in the intensive care unit(ICU).METHODS: In this prospective study, we observed patients with detained urethral catheters in the ICU of Shanghai Tenth People's Hospital between April 2011 and March 2013. The correlation between AWT and urinary bladder pressure(UBP) was analyzed by linear regression analysis. The effects of respiratory and body position on AWT were evaluated using the paired samples t test, whereas the effects of gender and body mass index(BMI) on baseline AWT(IAP<12 mm Hg) were assessed using one-way analysis of variance.RESULTS: A total of 51 patients were studied. A significant linear correlation was observed between AWT and UBP(R=0.986, P<0.01); the regression equation was Y=–1.369+9.57X(P<0.01). There were signif icant differences among the different respiratory phases and body positions(P<0.01). However, gender and BMI had no signif icant effects on baseline AWT(P=0.457 and 0.313, respectively).CONCLUSIONS: There was a signif icant linear correlation between AWT and UBP and respiratory phase, whereas body position had signif icant effects on AWT but gender and BMI did not. Therefore, AWT could serve as a simple, rapid, accurate, and important method to monitor IAP in critically ill patients.

Unsupervised calibration for noninvasive glucose-monitoring devices using mid-infrared spectroscopy

Noninvasive,glucose-monitoring technologies using infrared spectroscopy that have been studied typically require a calibration process that involves blood collection,which renders the methods somewhat invasive.We develop a truly noninvasive,glucose-monitoring technique using midinfrared spectroscopy that does not require blood collection for calibration by applying domain adaptation(DA)using deep neural networks to train a model that associates blood glucose concentration with mid-infrared spectral data without requiring a training dataset labeled with invasive blood sample measurements.For realizing DA,the distribution of unlabeled spectral data for calibration is considered through adversarial update during training networks for regression to blood glucose concentration.This calibration improved the correlation coeffcient between the true blood glucose concentrations and predicted blood glucose concentrations from 0.38 to 0.47.The result indicates that this calibration technique improves prediction accuracy for mid-infrared glucose measurements without any invasively acquired data.

An ethically guided preclinical device for phenotyping H_(2)production in laboratory rodents

Background:Dihydrogen(H_(2))is produced endogenously by the intestinal microbiota through the fermentation of diet carbohydrates.Over the past few years,numer-ous studies have demonstrated the significant therapeutic potential of H_(2)in various pathophysiological contexts,making the characterization of its production in labora-tory species of major preclinical importance.Methods:This study proposes an innovative solution to accurately monitor H_(2)pro-duction in free-moving rodents while respecting animal welfare standards.The devel-oped device consisted of a wire rodent cage placed inside an airtight chamber in which the air quality was maintained,and the H_(2)concentration was continuously analyzed.After the airtightness and efficiency of the systems used to control and maintain air quality in the chamber were checked,tests were carried out on rats and mice with different metabolic phenotypes,over 12 min to 1-h experiments and repeatedly.H_(2)production rates(HPR)were obtained using an easy calculation algorithm based on a first-order moving average.Results:HPR in hyperphagic Zucker rats was found to be twice as high as in control Wistar rats,respectively,2.64 and 1.27 nmol.s^(−1)per animal.In addition,the ingestion of inulin,a dietary fiber,stimulated H_(2)production in mice.HPRs were 0.46 nmol.s^(−1)for animals under control diet and 1.99 nmol.s^(−1)for animals under inulin diet.Conclusions:The proposed device coupled with our algorithm enables fine analysis of the metabolic phenotype of laboratory rats or mice with regard to their endogenous H_(2)production.

ORAL TRANSMUCOSAL BACK PERMEATION OF ALFENTANIL IN DOGS──A NOVEL METHOD TO DETERMINE BLOOD ALFENTANIL CONCENTRATION

This study explores a novel noninvasive method for monitoring blood alfentanil concentrations using a dog model. Alfentanil which 'back', permeated across the oral mucosa from the systemic circulation was collected from the oral mucosal surface and quantitated. The levels of the 'back' permeated alfentanil were found to closely reflect real time serum alfentanil concentrations. With further work, this finding may lead to a novel noninvasive method for monitoring real time serum alfentanil concentrations in its clinical applications.

The Feasibility of Flat, Portable and Wireless Device for Non-Invasive Peripheral Oxygenation Measurement over the Entire Body

Peripheral oxygenation level (SpO2) can provide vital information on body functions. Continuous monitoring facilitates effective diagnosis and treatment and can even be lifesaving. Clinical device monitor SpO2 using a clip, and measure light transmission through the tissue. This method limits the body locations of the clip’s placement and is sensitive to body movement, which hampers continuous SpO2 monitoring during wakefulness or sleep, thus decreasing its usability in clinics and its accessibility in homecare usage. We developed a portable, wireless, flat and low cost prototype for continuous monitoring of SpO2 that overcomes those limitations. The prototype enables convenient measurement in larger variety of body locations by spectrophotometric measurements of changes in the optical reflectance unlike other device that measure absorption through the tissue. The original design and signal processing enable reliable signal acquisition, synchronization and control. An Android’s application was developed to provide a user friendly interface for results display on smartphones. The prototype’s measurements were compared to commercial device that simultaneously measured heart rate frequency, transcutaneous oxygen tension (tcPO2) and SpO2. The prototype’s measurements accurately reflected changes caused by blood pulses, were correlated to the heart rate, and were sensitive to changes in oxygen saturation. Excellent real time behavior and synchronization were demonstrated between the hardware and smartphone software. Our prototype thus enables convenient SpO2 measurement over the entire body, while maintaining accuracy comparable to commercial device. Its smartphone application enables accessible and understandable results display to patients, care-givers and healthcare professionals. The application’s display and alert calibration flexibility facilitates the prototype’s usage in changing medical requirements and for various disease and conditions. A device based on this prototype can monitor continuously and accurately patients’ SpO2 without limiting their everyday activities or disturbing their sleep and can thus significantly im-prove their medical care in both clinics and home.

A non-invasive smart scaffold for bone repair and monitoring

Existing strategies for bone defect repair are difficult to monitor.Smart scaffold materials that can quantify the efficiency of new bone formation are important for bone regeneration and monitoring.Carbon nanotubes(CNT)have promising bioactivity and electrical conductivity.In this study,a noninvasive and intelligent monitoring scaffold was prepared for bone regeneration and monitoring by integrating carboxylated CNT into chemically cross-linked carboxymethyl chitosan hydrogel.CNT scaffold(0.5%w/v)demonstrated improved mechanical properties with good biocompatibility and electrochemical responsiveness.Cyclic voltammetry and electrochemical impedance spectroscopy of CNT scaffold responded sensitively to seed cell differentiation degree in both cellular and animal levels.Interestingly,the CNT scaffold could make up the easy deactivation shortfall of bone morphogenetic protein 2 by sustainably enhancing stem cell osteogenic differentiation and new bone tissue formation through CNT roles.This research provides new ideas for the development of noninvasive and electrochemically responsive bioactive scaffolds,marking an important step in the development of intelligent tissue engineering.

Impact of cavitation on lesion formation induced by high intensity focused ultrasound

High intensity focused ultrasound（HIFU） has shown a great promise in noninvasive cancer therapy. The impact of acoustic cavitation on the lesion formation induced by HIFU is investigated both experimentally and theoretically in transparent protein-containing gel and ex vivo liver tissue samples. A numerical model that accounts for nonlinear acoustic propagation and heat transfer is used to simulate the lesion formation induced by the thermal effect. The results showed that lesions could be induced in the samples exposed to HIFU with various acoustic pressures and pulse lengths. The measured areas of lesions formed in the lateral direction were comparable to the simulated results, while much larger discrepancy was observed between the experimental and simulated data for the areas of longitudinal lesion cross-section. Meanwhile,a series of stripe-wiped-off B-mode pictures were obtained by using a special imaging processing method so that HIFUinduced cavitation bubble activities could be monitored in real-time and quantitatively analyzed as the functions of acoustic pressure and pulse length. The results indicated that, unlike the lateral area of HIFU-induced lesion that was less affected by the cavitation activity, the longitudinal cross-section of HIFU-induced lesion was significantly influenced by the generation of cavitation bubbles through the temperature elevation resulting from HIFU exposures. Therefore, considering the clinical safety in HIFU treatments, more attention should be paid on the lesion formation in the longitudinal direction to avoid uncontrollable variation resulting from HIFU-induced cavitation activity.

Effect of temperature on noninvasive blood glucose monitoring in vivo using optical coherence tomography-corrigendum

The authors would like to apologize for some mistakes in the letter on Chinese Optics Letters vol. 12, no. 11, page 111701 and wish to make the corrections described below：