Recording Of Physiological Parameters Research Articles

Effect of Foliar Fertilization on the Physiological Parameters, Yield and Quality Indices of the Winter Wheat

The main purpose of the paper is to highlight the impact of foliar fertilization during the various growth stages of winter wheat and its role in achieving high-quality and superior production. Foliar fertilizers play a crucial role in calibrating and forming active growth intervals correlated with productivity factors. The research was conducted over a two-year period using the Andrada winter wheat variety. It involved the application of four different foliar fertilizers: basic mineral fertilization, FoliMAX Orange (two treatments and three treatments), FoliMAX CerealsMIX (two treatments and three treatments), and Microfert U (three treatments). Depending on the treatment, two or three applications of foliar with foliar fertilizers were carried out at various stages of winter wheat development, including pre-flowering and grain formation. The research method used to record physiological parameters was non-destructive (the leaves were not detached from the plant) and was based on the use of the CIRAS-3 foliar gas analyzer, which simultaneously determines several physiological and environmental indicators. As an indicator read by the device, photosynthesis was chosen for leaf temperature and leaf transpiration, correlated with production and quality indices. By applying the foliar fertilizer treatments to the wheat culture, we managed to increase production and improve the quality. After using different foliar fertilizers, the assimilation and physiological parameters had higher values of over 30 μmolm−2·s−1. Foliar fertilization applied to the winter wheat variety resulted in an average production increase between 450 and 765 kg·ha−1 and quality indices with a protein percentage between 11.5 and 12.6%, gluten content between 21.5 to 24.0% and the Zeleny index between 29.0 and 39.0%, and the mass of one thousand grains was between 48.0 and 50.5 g.

First Evaluation of a Newly Constructed Underwater Pulse Oximeter for Use in Breath-Holding Activities.

Studying risk factors in freediving, such as hypoxic blackout, requires development of new methods to enable remote underwater monitoring of physiological variables. We aimed to construct and evaluate a new water- and pressure proof pulse oximeter for use in freediving research. The study consisted of three parts: (I) A submersible pulse oximeter (SUB) was developed on a ruggedized platform for recording of physiological parameters in challenging environments. Two MAX30102 sensors were used to record plethysmograms, and included red and infra-red emitters, diode drivers, photodiode, photodiode amplifier, analog to digital converter, and controller. (II) We equipped 20 volunteers with two transmission pulse oximeters (TPULS) and SUB to the fingers. Arterial oxygen saturation (SpO2) and heart rate (HR) were recorded, while breathing room air (21% O2) and subsequently a hypoxic gas (10.7% O2) at rest in dry conditions. Bland-Altman analysis was used to evaluate bias and precision of SUB relative to SpO2 values from TPULS. (III) Six freedivers were monitored with one TPULS and SUB placed at the forehead, during a maximal effort immersed static apnea. For dry baseline measurements (n = 20), SpO2 bias ranged between −0.8 and −0.6%, precision between 1.0 and 1.5%; HR bias ranged between 1.1 and 1.0 bpm, precision between 1.4 and 1.9 bpm. For the hypoxic episode, SpO2 bias ranged between −2.5 and −3.6%, precision between 3.6 and 3.7%; HR bias ranged between 1.4 and 1.9 bpm, precision between 2.0 and 2.1 bpm. Freedivers (n = 6) performed an apnea of 184 ± 53 s. Desaturation- and resaturation response time of SpO2 was approximately 15 and 12 s shorter in SUB compared to TPULS, respectively. Lowest SpO2 values were 76 ± 10% for TPULS and 74 ± 13% for SUB. HR traces for both pulse oximeters showed similar patterns. For static apneas, dropout rate was larger for SUB (18%) than for TPULS (<1%). SUB produced similar SpO2 and HR values as TPULS, both during normoxic and hypoxic breathing (n = 20), and submersed static apneas (n = 6). SUB responds more quickly to changes in oxygen saturation when sensors were placed at the forehead. Further development of SUB is needed to limit signal loss, and its function should be tested at greater depth and lower saturation.

A flexible strain-responsive sensor fabricated from a biocompatible electronic ink via an additive-manufacturing process

Biosensor technologies are of great interest for applications in wearable electronics, soft robotics and implantable biomedical devices. To accelerate the adoption of electronics for chronic recording of physiological parameters in health and disease, there is a demand for biocompatible, conductive & flexible materials that can integrate with various tissues while remaining biologically inert. Conventional techniques used to fabricate biosensors, such as mask lithography and laser cutting, lack the versatility to produce easily customisable, micro-fabricated biosensors in an efficient, cost-effective manner. In this paper, we describe the development and characterisation of an electronic ink made from an environmentally sustainable copolymer - ω-pentadecalactone-co-ε-decalactone, (PDL) incorporating silver nanowires (AgNW), which are known for their antimicrobial and conductive properties. The composites were shown to possess a low percolation threshold (1% w/w of AgNW to PDL), achieve a low electrical resistance (320 ± 9 Ω/sq) and a high electrical capacitance (2.06 ± 0.06 µF/cm2). PDL nanocomposites were biocompatible, demonstrated in vitro through the promotion of neural adhesion and prevention of astrocyte activation. An optimised ink formulation was subsequently used to fabricate strain-responsive biosensors with high spatial resolution (sub – 100 µm) using a direct write additive manufacturing process. Using a customized in vitro set-up, the sensitivity of these biosensors to biologically-relevant strains was assessed under simulated physiological conditions for 21 days. Critically, these 3D printed biosensors have applications in chronic prophylactic monitoring of pressure changes within the body and related pathologies.

Forecasting Seizure Storms Using Epilepsy Wristband Sensors.

Machine Learning From Wristband Sensor Data for Wearable, Noninvasive Seizure Forecasting Meisel C, El Atrache R, Jackson M, Schubach S, Ufongene C, Loddenkemper T. Epilepsia. 2020;61(12):2653-2666. doi:10.1111/epi.16719Objective:Seizure forecasting may provide patients with timely warnings to adapt their daily activities and help clinicians deliver more objective, personalized treatments. Although recent work has convincingly demonstrated that seizure risk assessment is in principle possible, these early approaches relied largely on complex, often invasive setups including intracranial electrocorticography, implanted devices, and multichannel electroencephalography and required patient-specific adaptation or learning to perform optimally, all of which limit translation to broad clinical application. To facilitate broader adaptation of seizure forecasting in clinical practice, noninvasive, easily applicable techniques that reliably assess seizure risk without much prior tuning are crucial. Wristbands that continuously record physiological parameters, including electrodermal activity, body temperature, blood volume pulse, and actigraphy, may afford monitoring of autonomous nervous system function and movement relevant for such a task, hence minimizing potential complications associated with invasive monitoring and avoiding stigma associated with bulky external monitoring devices on the head.Methods:Here, we applied deep learning on multimodal wristband sensor data from 69 patients with epilepsy (total duration >2311 hours, 452 seizures) to assess its capability to forecast seizures in a statistically significant way.Results:Using a leave-one-subject-out cross-validation approach, we identified better-than-chance predictability in 43% of the patients. Time-matched seizure surrogate data analyses indicated forecasting not to be driven simply by time of day or vigilance state. Prediction performance peaked when all sensor modalities were used and did not differ between generalized and focal seizure types but generally increased with the size of the training data set, indicating potential further improvement with larger data sets in the future.Significance:Collectively, these results show that statistically significant seizure risk assessments are feasible from easy-to-use, noninvasive wearable devices without the need of patient-specific training or parameter optimization.

Machine learning from wristband sensor data for wearable, noninvasive seizure forecasting.

Seizure forecasting may provide patients with timely warnings to adapt their daily activities and help clinicians deliver more objective, personalized treatments. Although recent work has convincingly demonstrated that seizure risk assessment is in principle possible, these early approaches relied largely on complex, often invasive setups including intracranial electrocorticography, implanted devices, and multichannel electroencephalography, and required patient-specific adaptation or learning to perform optimally, all of which limit translation to broad clinical application. To facilitate broader adaptation of seizure forecasting in clinical practice, noninvasive, easily applicable techniques that reliably assess seizure risk without much prior tuning are crucial. Wristbands that continuously record physiological parameters, including electrodermal activity, body temperature, blood volume pulse, and actigraphy, may afford monitoring of autonomous nervous system function and movement relevant for such a task, hence minimizing potential complications associated with invasive monitoring and avoiding stigma associated with bulky external monitoring devices on the head. Here, we applied deep learning on multimodal wristband sensor data from 69 patients with epilepsy (total duration>2311hours, 452 seizures) to assess its capability to forecast seizures in a statistically significant way. Using a leave-one-subject-out cross-validation approach, we identified better-than-chance predictability in 43% of the patients. Time-matched seizure surrogate data analyses indicated forecasting not to be driven simply by time of day or vigilance state. Prediction performance peaked when all sensor modalities were used, and did not differ between generalized and focal seizure types, but generally increased with the size of the training dataset, indicating potential further improvement with larger datasets in the future. Collectively, these results show that statistically significant seizure risk assessments are feasible from easy-to-use, noninvasive wearable devices without the need of patient-specific training or parameter optimization.

Instrument implementation of an automated complex for recording physiological parameters of drivers

Goal of research: creation of an automated complex for quick and effective identification of an unacceptable condition of drivers before going to run and predicting their physiological state during a work shift. To achieve this goal in the creation of devices for the automated complex the following methods were used: photoplethysmographic method, pulse oximetric method, thermometric method. In the course of the research, results were achieved that make it possible to record physiological parameters of drivers with high reliability. This is achieved thanks to the use of the “isobestic point” photoplethysmogram in the registration at a length of 805 nm, the use of a two-channel pulse oximeter at wavelengths of 660 nm and 910 nm.

Perception and Performance on a Virtual Reality Cognitive Stimulation for Use in the Intensive Care Unit: A Non-randomized Trial in Critically Ill Patients.

Background: Newly acquired long-term cognitive impairments are common among survivors of critical illness. They have been linked to the stressful situation that patients experience in the intensive care unit (ICU). In this paper we use virtual reality (VR) technology to comfort critically ill patients and reduce stress during their ICU stay. We investigate the acceptance, comfort, recollection, and visual perception of VR stimulation and how it affects physiological parameters.Methods: A VR head-mounted display was used to present immersive nature scenes to 33 critically ill cardiac surgery patients [mean age 63 years (range 32–83)]. Data was collected with an eye tracker fitted inside the VR head-mounted display to measure eye movements (250 Hz) and sensors to record physiological parameters (240 Hz). Patients received VR stimulation (for 5 min.) prior to ICU admission, during ICU stay, and 3 months after discharge. Acceptance, recollection and comfort were assessed with validated questionnaires.Results: The number of gazed meaningful objects per minute was significantly lower during the ICU session compared to pre- and follow-up sessions, whereas mean duration of fixation on meaningful moving objects did not differ between the sessions. While respiratory rate decreased significantly during VR stimulation, heart rate and blood pressure remained constant. Post-ICU rating of VR acceptance during ICU stay was moderate to high and discomfort low. Recollection of VR was high [28/33 patients (84.8%)], while recollection of ICU stay was low [10/33 patients (30.3%)].Conclusion: Eye movements indicate that patients were able to perceive and process cognitive stimulation during their ICU stay. VR was recalled better than the rest of the ICU stay and well accepted. Decreased respiratory rate during stimulation indicate a relaxing effect of VR.

Comparing the Relaxing Effects of Different Virtual Reality Environments in the Intensive Care Unit: Observational Study.

BackgroundAfter a prolonged intensive care unit (ICU) stay, approximately 50%-75% of all critically ill patients suffer from neurocognitive late effects and a reduction of health-related quality of life. It is assumed that the noisy and stressful ICU environment leads to sensory overload and deprivation and potentially to long-term cognitive impairment.ObjectiveIn this study, we investigated three different virtual reality environments and their potentially restorative and relaxing effects for reducing sensory overload and deprivation in the ICU.MethodsA total of 45 healthy subjects were exposed to three different environments, each 10 minutes in length (dynamic, virtual, natural, and urban environments presented inside the head-mounted display, and a neutral video on an ICU TV screen). During the study, data was collected by validated questionnaires (ie, restoration and sickness) and sensors to record physiological parameters (240 hertz).ResultsThe results showed that the natural environment had the highest positive and restorative effect on the physiological and psychological state of healthy subjects, followed by the urban environment and the ICU TV screen.ConclusionsOverall, virtual reality stimulation with head-mounted display using a dynamic, virtual and natural environment has the potential, if directly used in the ICU, to reduce sensory overload and deprivation in critically ill patients and thus to prevent neurocognitive late effects.

Performance of the Afferent Limb of Rapid Response Systems in Managing Deteriorating Patients: A Systematic Review.

Introduction The clinical components of the rapid response system (RRS) are the afferent limb, to ensure identification of in-hospital patients who deteriorate and activation of a response, and the efferent limb, to provide the response. This review aims to evaluate the factors that influence the performance of the afferent limb in managing deteriorating ward patients and their effects on patient outcomes. Methods A systematic review was performed for the years 1995–2017 by employing five electronic databases. Articles were included assessing the ability of the ward staffs to monitor, recognize, and escalate care to patient deterioration. The findings were summarized using a narrative approach. Results Thirty-one studies met the inclusion criteria. The analysis revealed major themes enclosing several factors affecting management of patients having sudden deterioration. The monitoring and recognition process was conditioned by the lack of recording of physiological parameters, the influence of facilitators, including staff education and training, and barriers, including human and environmental factors, and poor compliance with the calling criteria. The escalation of care process highlighted the influence of cultural barriers and personal judgment on RRS activation. Mainly, delayed team calls were factors strongly associated with the increased risk of unplanned admissions to the intensive care unit and length of stay, hospital length of stay and mortality, and 30-day mortality. Conclusions A combination of factors affects the timely identification and response to sudden deterioration by general ward staffs, leading to suboptimal care of patients, delayed or failed activation of RRS teams, and increased risks of worsening outcomes. The research efforts and clinical involvement to improve the governance of the factors limiting the performance of the afferent limb may ensure proper management of hospitalized patients showing physiological deterioration.

Monitoring System for Laboratory Mice Transportation: A Novel Concept for the Measurement of Physiological and Environmental Parameters

Laboratory mice are used in biomedical research as “models” for studying human disease. These mice may be subject to significant levels of stress during transportation that can cause alterations that could negatively affect the results of the performed investigation. Here, we present the design and realization of a prototypical transportation container for laboratory mice, which may contribute to improved laboratory animal welfare. This prototype incorporates electric potential integrated circuit (EPIC) sensors, which have been shown to allow the recording of physiological parameters (heart rate and breathing rate) and other sensors for recording environmental parameters during mouse transportation. This allows for the estimation of the stress levels suffered by mice. First experimental results for capturing physiological and environmental parameters are shown and discussed.

Development of Low Cost Miniature USB Based Data Acquisition System for Biomedical Instrumentation

In biomedical instrumentation, computer based data acquisition system is required for recording of physiological parameters and bioelectric signals, which allows signal processing, display, analysis and storage in digital media. However, Most of the commercially available PC based Data Acquisition systems are of very high cost and requires specific commercial software, again at a very high cost. Moreover, if the data is not stored in raw binary or known format, it is not possible for the user to use the data in other system or software of their own choice. Therefore, a low cost, simple and open source PC based data acquisition system for biomedical application would be very useful for biomedical instrument developers and researchers in the low resource countries. In this work, we present such development of data acquisition system. The developed system utilizes an 8-bit ordinary low cost microcontroller and some electronic circuit component to develop the data acquisition system and implementation of USB 1.1 (Universal Serial Bus) interface to PC. The onboard 10-bit ADC of the microcontroller was used for analog data sampling. Two sampling and data transfer mode is implemented, (i) Continuous mode with low sampling rate (800 sample/sec) and practically real time plotting and (ii) Batch mode, with high sampling rate (76.9 k sample/sec) but with batch type plotting. To evaluate the system, PC side GUI (Graphical User Interface) software was also developed. The GUI of system shows that a test sinusoidal signal is reproduced very nicely without any amplitude and phase distortion within the frequency band of 1 to 10 KHz. The system is suitable for low frequency bioelectric signals like ECG, EEG etc. and as well as high frequency signal like EMG, NCV etc. The system is low cost, miniature, simple, and efficient and being used in several indigenously developed medical devices like ECG, EMG, NCV and FIM [Rabbani et al, 1999] at the authors’ department with excellent satisfactory results.Bangladesh Journal of Medical Physics Vol.10 No.1 2017 1-11

Pre-exercise exposure to the treadmill setup changes the cardiovascular and thermoregulatory responses induced by subsequent treadmill running in rats

ABSTRACTDifferent methodological approaches have been used to conduct experiments with rats subjected to treadmill running. Some experimenters have exposed rats to the treadmill setup before initiating exercise to minimize the influences of handling and being placed in an anxiety-inducing environment on the physiological responses to subsequent running. Other experimenters have subjected rats to exercise immediately after placing them on the treadmill. Thus, the present study aimed to evaluate the effects of pre-exercise exposure to the treadmill on physical performance and cardiovascular and thermoregulatory responses during subsequent exercise. Male Wistar rats were subjected to fatiguing incremental-speed exercise at 24°C immediately after being placed on the treadmill or after being exposed to the treadmill for 70 min following removal from their home cages. Core body temperature (TCORE), tail-skin temperature (TSKIN), heart rate (HR) and mean arterial pressure (MAP) were recorded throughout the experiments. Rats exposed to the treadmill started exercise with higher TCORE, lower HR and MAP, and unaltered TSKIN. This exposure did not influence performance, but it markedly affected the exercise-induced increases in the four physiological parameters evaluated; for example, the TSKIN increased earlier and at a higher TCORE. Moreover, previous treadmill exposure notably allowed expected exercise-induced changes in cardiovascular parameters to be observed. Collectively, these data indicate that pre-exercise exposure to the treadmill induces important effects on physiological responses during subsequent treadmill running. The present data are particularly relevant for researchers planning experiments involving physical exercise and the recording of physiological parameters in rats.

Validação da versão Brasileira da Escala Comportamental de Dor ( Behavioral Pain Scale ) em adultos sedados e sob ventilação mecânica

The Behavioral Pain Scale is a pain assessment tool for uncommunicative and sedated Intensive Care Unit patients. The lack of a Brazilian scale for pain assessment in adults mechanically ventilated justifies the relevance of this study that aimed to validate the Brazilian version of Behavioral Pain Scale as well as to correlate its scores with the records of physiological parameters, sedation level and severity of disease.Twenty-five Intensive Care Unit adult patients were included in this study. The Brazilian Behavioral Pain Scale version (previously translated and culturally adapted) and the recording of physiological parameters were performed by two investigators simultaneously during rest, during eye cleaning (non-painful stimulus) and during endotracheal suctioning (painful stimulus).High values of responsiveness coefficient (coefficient=3.22) were observed. The Cronbach's alpha of total Behavioral Pain Scale score at eye cleaning and endotracheal suctioning was 0.8. The intraclass correlation coefficient of total Behavioral Pain Scale score was ≥ 0.8 at eye cleaning and endotracheal suctioning. There was a significant highest Behavioral Pain Scale score during application of painful procedure when compared with rest period (p≤0.0001). However, no correlations were observed between pain and hemodynamic parameters, sedation level, and severity of disease.This pioneer validation study of Brazilian Behavioral Pain Scale exhibits satisfactory index of internal consistency, interrater reliability, responsiveness and validity. Therefore, the Brazilian Behavioral Pain Scale version was considered a valid instrument for being used in adult sedated and mechanically ventilated patients in Brazil.

Improving Patient Safety through the Use of Nursing Surveillance.

Surveillance and monitoring each represent a distinct process in patient care. Monitoring involves observation, measurement, and recording of physiological parameters, while surveillance is a systematic, goal-directed process based on early detection of signs of change, interpretation of the clinical implications of such changes, and initiation of rapid, appropriate interventions. Through use of an illustrative clinical example based on Early Warning System scoring and rapid response teams, this article seeks to distinguish between nurse monitoring and surveillance to demonstrate the impact of surveillance on improving both care processes and patient care. Using a clinical example, differences between surveillance and monitoring as a trigger for deployment of the rapid response team were reviewed. The use of surveillance versus monitoring resulted in a mean reduction in rapid response team deployment time of 291 minutes. The median hospital length of stay for patients whose clinical care included using surveillance to initiate the deployment of the rapid response team was reduced by 4 days. Monitoring relies on observation and assessment while nursing surveillance incorporates monitoring with recognition and interpretation of the clinical implications of changes to guide decisions about subsequent actions. The clinical example described here supports that the use of an automated surveillance system versus monitoring had a measurable impact on clinical care.

Validation of the Brazilian version of Behavioral Pain Scale in adult sedated and mechanically ventilated patients

Background and objectivesThe Behavioral Pain Scale is a pain assessment tool for uncommunicative and sedated Intensive Care Unit patients. The lack of a Brazilian scale for pain assessment in adults mechanically ventilated justifies the relevance of this study that aimed to validate the Brazilian version of Behavioral Pain Scale as well as to correlate its scores with the records of physiological parameters, sedation level and severity of disease. MethodsTwenty-five Intensive Care Unit adult patients were included in this study. The Brazilian Behavioral Pain Scale version (previously translated and culturally adapted) and the recording of physiological parameters were performed by two investigators simultaneously during rest, during eye cleaning (non-painful stimulus) and during endotracheal suctioning (painful stimulus). ResultsHigh values of responsiveness coefficient (coefficient=3.22) were observed. The Cronbach's alpha of total Behavioral Pain Scale score at eye cleaning and endotracheal suctioning was 0.8. The intraclass correlation coefficient of total Behavioral Pain Scale score was ≥0.8 at eye cleaning and endotracheal suctioning. There was a significant highest Behavioral Pain Scale score during application of painful procedure when compared with rest period (p≤0.0001). However, no correlations were observed between pain and hemodynamic parameters, sedation level, and severity of disease. ConclusionsThis pioneer validation study of Brazilian Behavioral Pain Scale exhibits satisfactory index of internal consistency, interrater reliability, responsiveness and validity. Therefore, the Brazilian Behavioral Pain Scale version was considered a valid instrument for being used in adult sedated and mechanically ventilated patients in Brazil.

The Effect of Audio-Visual Biofeedback on Muscle Relaxation

The aim of the study was to explore the effect of audio-visual biofeedback on patients’ ability to control their own muscle tension, relaxing them. The upper trapezius muscle, which is located on the back of the neck and shoulder part being one of the most tensed human muscles, was studied. The study included 18 volunteers, each had 2–3 relaxation trainings using 4 different biological feedback methods and recording of physiological parameters and patients’ subjective opinion. The obtained measurements were examined to determine the relaxation characteristics of different types of feedback. As a result, it was concluded that the audio-visual biofeedback was recommended to use for muscle relaxation purposes.

Methods to explore productive behaviors in personal and extrapersonal space.

Methods to explore productive behaviors in personal and extrapersonal space.

Implantation of Radiotelemetry Transmitters Yielding Data on ECG, Heart Rate, Core Body Temperature and Activity in Free-moving Laboratory Mice

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a manageable size and relatively easy to house. These factors, together with the availability of a wealth of spontaneous and experimentally induced mutants, make laboratory mice ideally suited to a wide variety of research areas. In cardiovascular, pharmacological and toxicological research, accurate measurement of parameters relating to the circulatory system of laboratory animals is often required. Determination of heart rate, heart rate variability, and duration of PQ and QT intervals are based on electrocardiogram (ECG) recordings. However, obtaining reliable ECG curves as well as physiological data such as core body temperature in mice can be difficult using conventional measurement techniques, which require connecting sensors and lead wires to a restrained, tethered, or even anaesthetized animal. Data obtained in this fashion must be interpreted with caution, as it is well known that restraining and anesthesia can have a major artifactual influence on physiological parameters1, 2. Radiotelemetry enables data to be collected from conscious and untethered animals. Measurements can be conducted even in freely moving animals, and without requiring the investigator to be in the proximity of the animal. Thus, known sources of artifacts are avoided, and accurate and reliable measurements are assured. This methodology also reduces interanimal variability, thus reducing the number of animals used, rendering this technology the most humane method of monitoring physiological parameters in laboratory animals3, 4. Constant advancements in data acquisition technology and implant miniaturization mean that it is now possible to record physiological parameters and locomotor activity continuously and in realtime over longer periods such as hours, days or even weeks3, 5. Here, we describe a surgical technique for implantation of a commercially available telemetry transmitter used for continuous measurements of core body temperature, locomotor activity and biopotential (i.e. onelead ECG), from which heart rate, heart rate variability, and PQ and QT intervals can be established in freeroaming, untethered mice. We also present pre-operative procedures and protocols for post-operative intensive care and pain treatment that improve recovery, well-being and survival rates in implanted mice5, 6.

Implantation of Radiotelemetry Transmitters Yielding Data on ECG, Heart Rate, Core Body Temperature and Activity in Free-moving Laboratory Mice

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a manageable size and relatively easy to house. These factors, together with the availability of a wealth of spontaneous and experimentally induced mutants, make laboratory mice ideally suited to a wide variety of research areas.In cardiovascular, pharmacological and toxicological research, accurate measurement of parameters relating to the circulatory system of laboratory animals is often required. Determination of heart rate, heart rate variability, and duration of PQ and QT intervals are based on electrocardiogram (ECG) recordings. However, obtaining reliable ECG curves as well as physiological data such as core body temperature in mice can be difficult using conventional measurement techniques, which require connecting sensors and lead wires to a restrained, tethered, or even anaesthetized animal. Data obtained in this fashion must be interpreted with caution, as it is well known that restraining and anesthesia can have a major artifactual influence on physiological parameters1, 2.Radiotelemetry enables data to be collected from conscious and untethered animals. Measurements can be conducted even in freely moving animals, and without requiring the investigator to be in the proximity of the animal. Thus, known sources of artifacts are avoided, and accurate and reliable measurements are assured. This methodology also reduces interanimal variability, thus reducing the number of animals used, rendering this technology the most humane method of monitoring physiological parameters in laboratory animals3, 4. Constant advancements in data acquisition technology and implant miniaturization mean that it is now possible to record physiological parameters and locomotor activity continuously and in realtime over longer periods such as hours, days or even weeks3, 5.Here, we describe a surgical technique for implantation of a commercially available telemetry transmitter used for continuous measurements of core body temperature, locomotor activity and biopotential (i.e. onelead ECG), from which heart rate, heart rate variability, and PQ and QT intervals can be established in freeroaming, untethered mice. We also present pre-operative procedures and protocols for post-operative intensive care and pain treatment that improve recovery, well-being and survival rates in implanted mice5, 6.

Where Should We Manage Diabetic Ketoacidosis (DKA) in Children?

Background: The leading cause of mortality for children with diabetes is DKA, with cerebral oedema the main cause of death. The onset of cerebral oedema is unpredictable; therefore the key to improving survival is early recognition and aggressive management. The British Society for Paediatric Endocrinology and Diabetes (BSPED)guidelines for DKA were updated in 2009; listing the recommended inpatient observations and emphasising “safe nursing” on general paediatric wards, acknowledging that children with DKA are high dependency patients and require 1:1 nursing. Methods: We audited Paediatric DKA admissions in 2009 (n=26, 8 admitted to HDU) comparing the quality of physiological data collection and outcome between those admitted to the general wards (1:4 nursing) and to HDU (1:2 nursing). Results: The HDU patients were more acidotic (pH 6.9 (range 6.8-7.2) vs 7.2 (7.1-7.3)) (p=0.03) and tended to be more likely to be new diagnoses (71% vs 41%). Children with DKA on HDU had better recording of fluid balance, hourly blood sugars, physiological and neurological observations than those nursed on general paediatric wards. Conclusions: Recording of physiological parameters in a HDU setting was more complete than in a general Paediatric setting. The BSPED guidelines recommend one to one nursing for children with DKA on Intravenous insulin, which may not be feasible in all units. Accurate observations and swift intervention are necessary to improve survival from cerebral oedema. Therefore children with DKA should be managed in a regional HDU or a large DGH with at least 1:2 nursing.