Thermal skin reference values in healthy late pregnancy

Electronic Design for Wearables Devices Addressed from a Gender Perspective: Cross-Influences and a Methodological Proposal

The design of wearable devices has been approached from many perspectives over the years, mainly from a functionality, electronics, mechanics, usability, wearability, or product design perspective. However, there is a missing point in these approaches: the gender perspective. Gender intersects with every approach and, considering the interrelationships and dependencies, can achieve a better adherence, reach a wider audience, and even change the conception of the wearables design paradigm. The electronics design addressed from a gender perspective must consider both the morphological and anatomical impacts and those emanating from socialization. This paper presents an analysis of the different factors to consider when designing the electronics of a wearable device, including the functionality to implement, sensors, communications, or the location, together with their interdependencies, and proposes a user-centered methodology that contemplates a gender perspective at every stage. Finally, we present a use case that validates the proposed methodology in a real design of a wearable device for the prevention of gender-based violence cases. For the application of the methodology, 59 experts have been interviewed, 300 verbatims have been extracted and analyzed, a dataset from the data of 100 women has been created and the wearable devices have been tested for a week by 15 users. The electronics design needs to be addressed from a multidisciplinary approach, by rethinking the decisions taken for granted and analyzing the implications and interrelationships from a gender perspective. We need to enroll more diverse people at every design stage and include gender as one of the variables to study.

Heat loss responses at rest and during exercise in pregnancy: A scoping review

BACKGROUND

The teratogenic risk associated with maternal hyperthermia (i.e., core temperature ≥39.0 °C) has been a crucial motive in understanding thermoregulatory responses in pregnancy. To date, a substantial number of studies have focused on core temperature responses in a wide range of exercise intensities, duration, and ambient temperatures. Fortunately, none have reported core temperatures exceeding 39.0 °C. Nonetheless, there are limited studies that have provided substantial insight into both dry and evaporative heat loss mechanisms involved in facilitating the maintenance of core temperature (≥39.0 °C) during heat stress in pregnant women. The purpose of this scoping review was to summarize the available literature that has assessed heat loss responses in studies of human pregnancy.

METHODS

A search strategy was developed combining the terms pregnancy, thermoregulation, and adaptation. A systematic search was performed in the following databases: PubMed, Embase, Scopus, and ProQuest. Studies eligible for inclusion included pregnant women between the ages of 18-40 years old, and at least one measurement of the following: sweating, blood flow, skin temperature, and behavioural responses. Retrieved data were categorized as evaporative (sweating), dry or behavioural heat loss responses and summarized narratively.

RESULTS

Thirty-three studies were included in this review (twenty-nine measured physiological responses and four measured behavioural responses). Studies suggest that during exercise, evaporative (sweating) and dry (skin blood flow and temperature) heat loss responses increase from early to late pregnancy in addition to greater cardiac output, blood volume and reduced vascular resistance. Behavioural practices related to heat loss responses are also influenced by cultural/religious expectations, personal preferences and sociodemographics.

CONCLUSION

The findings from this review suggest that pregnancy modifies evaporative (sweating), dry and behavioural heat loss. However, future studies have an opportunity to compare heat loss measurements accounting for gestational weight gain and thermal sensation/comfort scale to associate physiological responses with perceptual responses across pregnancy.

Abdominal Cutaneous Thermography and Perfusion Mapping after Caesarean Section: A Scoping Review

Introduction: Caesarean section (CS) is the most prevalent surgical procedure in women. The incidence of surgical site infection (SSI) after CS remains high but recent observations of CS wounds using infrared thermography has shown promise for the technique in SSI prognosis. Although thermography is recognised as a 'surrogate' of skin perfusion, little is known of the relationship between skin temperature and skin perfusion in the context of wound healing. Aim: To assess the extent of literature regarding the application of infrared thermography and mapping of abdominal cutaneous perfusion after CS. Methods: Wide eligibility criteria were used to capture all relevant studies of any design, published in English, and addressing thermal imaging or skin perfusion mapping of the abdominal wall. The CINAHL and MEDLINE databases were searched, with two independent reviewers screening the title and abstracts of all identified citations, followed by full-text screening of relevant studies. Data extraction from included studies was undertaken using a pre-specified data extraction chart. Data were tabulated and synthesised in narrative format. Results: From 83 citations identified, 18 studies were considered relevant. With three additional studies identified from the reference lists, 21 studies were screened via full text. None of the studies reported thermal imaging and cutaneous perfusion patterns of the anterior abdominal wall. However, two observational studies partially met the inclusion criteria. The first explored analysis methodologies to 'interrogate' the abdominal thermal map. A specific thermal signature ('cold spots') was identified as an early 'flag' for SSI risk. A second study, by the same authors, focusing on obesity (a known risk factor for SSI after CS) showed that a 1 °C lower abdominal skin temperature led to a 3-fold odds of SSI. Conclusion: There is a significant gap in knowledge on how to forewarn of wound complications after CS. By utilising the known association between skin temperature and blood flow, thermographic assessment of the wound and adjacent thermal territories has potential as a non-invasive, independent, imaging option with which to identify tissue 'at risk'. By identifying skin 'hot' or 'cold' spots, commensurate with high or low blood flow regions, there is potential to shed light on the underlying mechanisms leading to infective and non-infective wound complications.

Thermal imaging of the fetus: An empirical feasibility study

Digital Infrared Thermal Imaging (DITI) has much potential in the field of maternal-fetal health and wellbeing research. The fact that it is totally non-invasive is particularly important in this context. The purpose of this study was, for the first time, to assess DITI’s ability to record fetal presentation and position, and other pregnancy-related physiological factors, via their superficial thermal prints. Ten healthy pregnant women (approximately 34–37 weeks of gestation) were recorded with two thermal imaging cameras (Flir C3 and i3 TE-Q1) from five different viewpoints. Participants’ views about the use of DITI in research and clinical practice were also assessed by a completion of a survey. Free hand polygon region of interests (ROIs) were drawn in order to include the entire anatomical area for investigation. The use of free hand polygon ROIs showed high reliability. Thermal images analysis revealed that fetuses presenting cephalically can be identified by the use of DITI, under specific conditions. Fetal movements influenced the thermal patterns that were produced. Future studies need to verify the heat patterns on the skin related to the placenta location, in order to understand the produced thermal recordings. Pregnant women rated the idea of using DITI in research and clinical practice very highly. This work represents a first contribution towards the use of DITI for the recording of fetal presentation and position. As it does not require direct contact and since it is completely non-invasive, it could be used to record maternal-fetal dynamic dyadic interaction in pregnancy. However, although the preliminary results are promising, further trans-disciplinary studies with a well-established protocol, more sophisticated thermal cameras, and bigger cohorts are needed.

Principal Component Analysis of Dynamic Thermography Data from Pregnant and Non-Pregnant Women

In this work we propose a novel approach for the analysis ofdynamic thermography data based on the application of principal component analysis to thermal video data. The proposed approach is applied to thermal video recordings of the abdominal region of pregnant and non-pregnant female participants, and reveals consistent temperature trends across participants that to date have not been reported. Both for the pregnant and non-pregnant participants, the first principal component was found to describe approximately 80% of the total variance, and when combined, the first three principal components explained more than 90% of the total variance. The presence of consistent temporal components across participants is indicative of common passive as well as active underlying mechanisms thatgive rise to the observed temperature patterns. The outcome of this investigation supports further development and application of the proposedmethod in obstetrics and other medical fields.

Registration of Dynamic Thermography Data of the Abdomen of Pregnant and Non-Pregnant Women

To date the use of thermography in the context of obstetrics has been primarily limited to the acquisition and analysis of static thermal images. In contrast, dynamic thermography involves the acquisition of a sequence of thermal images, taking into account temporal variations that would otherise be overlooked. However, dynamic recordings of regions of interest in human participants are likely to be affected by unavoidable participant movement due to breathing and other involuntary movements. In this work, a triangulation-based video registration technique using local affine transformations is proposed to register the abdominal region in dynamic thermal sequences. The proposed method is tested on one hour recordings of thermal data obtained from 10 pregnant and 10 non-pregnant female participants. The results obtained show that the proposed approach can compensate for movements and significantly improve region alignment throughout the thermal image sequence, thereby facilitating subsequent analysis of spatiotemporal temperature data in the considered image sequence.

THERMAL IMAGING AS AN ADJUNCT TOOL FOR IDENTIFYING FETAL GROWTH – A PILOT STUDY

Monitoring the fetal growth and diagnosing any possible abnormality plays a vital role in ensuring the healthy growth of a fetus. Certain health issues like Hyperthermia, Premature Rupture of Membranes (PROM) and Intrauterine Growth Restriction (IUGR) has to be diagnosed early. A pilot study comprising of 27 pregnant and 2 non-pregnant subjects was conducted to check the effectiveness of Thermal imaging in predicting the fetal growth. The heat dissipated by the fetus to the maternal abdominal wall is acquired as a surface thermal distribution. These images were processed qualitatively and quantitatively for better understanding. There was a consistent higher thermal pattern for pregnant women. A more pronounced temperature pattern is notable in the umbilical region that correlates with gestation age. However, as thermal pattern varies with age, gestation period and BMI, it is advisable to track the same person and compare the images for better assessment. This pilot study justifies the need for more elaborate study in building a database for classification and interpretation of thermogram to detect fetal abnormality with reduced human interpretation.

Avaliação da mama na lactação por termografia e presença de dor

Resumo Objetivo: Identificar evidências científicas das alterações na mama puerperal baseadas no exame clínico, na medição da dor por algometria de pressão e termografia. Métodos: Estudo descritivo, experimental, de abordagem qualiquantitativa, realizado com seis lactantes em um Banco de Leite Humano. Por meio de exame clínico, algometria de pressão e termografia, foram coletados dados das mamas em fase puerperal. Efetuou-se a análise descritiva das variáveis quantitativas expressas por médias, valores mínimos, máximos e desvios-padrão. Resultados: As mamas flácidas foram as mais frias com temperatura média de 32,7°C (DP±0,32386) e mais tolerantes à dor, com média de 1,87 kgf (DP±0,29558). Quanto maior a intensidade do ingurgitamento, maior foi a temperatura encontrada. A análise das imagens foram realizadas utilizando o software Therma CAM™ 2,9 (FLIR Systems, Inc). Conclusão: Os resultados indicam que, a partir do exame clínico, algometria de pressão e termografia infravermelha, foi possível delinear um padrão diferencial entre os vários eventos que acometem a mama no processo da lactação.