Systemic infection, major surgery, trauma and many other causes can lead to impaired organ function. Compensated shock is not detected by global hemodynamic and oxygen measurements, as they take no account for regional variations. Focus has therefore gradually turned from looking at systemic changes to selective investigations of regional blood flow and ischemia. This thesis presents a series of experiments evaluating new application and validation of various monitoring techniques. An experimental porcine model with anesthetized and invasively monitored animals was used. The circulatory interventions included endotoxin infusion (septic shock), aortic constriction and selective clamping of splanchnic arteries. The aim was to compare air with saline tonometry, to validate the intraperitoneal use of tonometry and to reexamine the use of endoluminal reflectance pulse oxymetry. To investigate the relative contributions of regional blood flow and detection of ischemia, measurements of hepatic venous oxygen saturation (ShvO2), lactate concentrations and PCO2 gap were used. Our findings support the use of air instead of saline as the preferred technique for tonometric measurements. With the intraperitoneal application of tonometry we gain more information on regional aspects of the splanchnic circulation, and it appears to be a reliable monitoring option for early detection of ischemia in the small intestine. Measurements of ShvO2 will give an overall reflection of the intestinal circulation. The sigmoid colonic pulse oximetry showed a non-linear response in relation to regional blood flow, and will therefore not be able to detect gradual changes in oxygen saturation. Determination of the regional to endtidal PCO2 gap might prove valuable for monitoring of the intestinal circulation. Because of sophisticated interactions between portal and hepatic arterial blood flow and hepatic compensation for regional ischemia, a combination of monitoring techniques might be needed. The results of this study will hopefully encourage clinical evaluation of intraperitoneal tonometry and endtidal PCO2 gap recordings for non-invasive, semi-continuous, trend monitoring of the splanchnic circulation.

No description available.

Le délirium est un état confusionnel aigu se manifestant entre autres par de l’agitation, de la léthargie (APA, 2013). Le délirium survient chez près de la moitié des patients subissant une chirurgie cardiaque malgré les interventions de prévention basées sur des guides de pratique clinique (Gosselt et al., 2015). Les complications associées au délirium sont importantes incluant une augmentation de la durée de séjour et un ralentissement du rétablissement (Inouye, Wastendrop & Saczynski, 2013; Saczynski et al., 2012). Cette étude portait sur le développement et l’évaluation d’une nouvelle intervention infirmière de mentorat visant à faciliter la participation d’un aidant familial dans la gestion du délirium. L’étude portait également sur la validité d’une nouvelle mesure de monitoring du délirium, l’oxymétrie cérébrale. Le but principal de cette étude pilote randomisée était d’évaluer l’acceptabilité et la faisabilité du devis et de l’intervention infirmière de mentorat, ainsi que la validité de l’oxymétrie cérébrale. Le but secondaire était d’évaluer les effets préliminaires de l’intervention. Trente dyades comprenant un patient présentant un délirium post-chirurgie cardiaque et un aidant familial ont été assignées aléatoirement au groupe contrôle recevant les soins usuels ou au groupe recevant l’intervention infirmière. L’intervention, ancrée dans une approche caring, visait à faciliter la transition des aidants dans un rôle participatif auprès de leur proche atteint de délirium ainsi qu’à favoriser le rehaussement de leur sentiment d’efficacité personnelle. L’indicateur principal d’évaluation de l’acceptabilité du devis était l’obtention du consentement d’au moins 75% des aidants approchés pour participer à l’étude. Par la suite, l’acceptabilité et la faisabilité ont été évaluées en se basant sur des critères d’évaluation des études pilotes pour le devis, par exemple, sur des données de recrutement et du domaine de l’évaluation d’interventions infirmières pour l’intervention, par exemple, la satisfaction des participants. Les effets préliminaires de l’intervention pour les patients ont été mesurés au moyen d’un score de sévérité du délirium, du nombre de complications, de la durée du séjour et du rétablissement psychofonctionnel. Auprès des aidants, des scores d’anxiété et d’efficacité personnelle ont été obtenus. Afin de tester la validité de la nouvelle mesure, les valeurs d’oxymétrie cérébrale ont été comparées à des scores de trois échelles d’évaluation du délirium validées. L’indicateur principal d’acceptabilité du devis, a été atteint avec un taux de consentement chez les aidants de 76,9 %. Cependant, le recrutement s’est avéré un grand défi, principalement parce que la prévalence des délirium détectés fut moindre qu’anticipée. L'intervention était acceptable et réalisable, comme en témoigne la participation des aidants familiaux. Les résultats de sévérité du délirium se sont avérés similaires dans les deux groupes, tout comme ceux relatifs aux complications. Les autres mesures de résultats ont présenté une tendance favorisant le groupe intervention dont une durée d’hospitalisation plus courte ainsi qu’un niveau d’anxiété moindre et d’un niveau sentiment d’efficacité personnelle plus élevé chez les aidants. Un effet statistiquement significatif de l’intervention favorisant le groupe intervention a été observé sur le rétablissement psychofonctionnel (p = 0,01). Une relation statistiquement significative entre les valeurs d’oxymétrie cérébrale et la présence et la sévérité du délirium a été observée (p ≤ 0,001). Cette étude contribue à l’avancement des connaissances par la démonstration de l’acceptabilité et la faisabilité d’une intervention pour rehausser la gestion du délirium par un mentorat des aidants familiaux. Une autre contribution réside dans les résultats prometteurs quant à la validité de l’oxymétrie cérébrale comme nouvelle mesure de monitoring du délirium qui pourra rehausser la détection et la gestion du délirium. / Delirium is an acute confusional state accompanied by agitation or lethargy (APA, 2013). Despite the prevention strategies based on clinical practice guidelines, nearly half of the patients undergoing a cardiac surgery will present delirium (Gosselt et al., 2015). Complications of delirium are important and include increased length of stay in addition to a slower recovery (Inouye, Wastendrop & Saczynski, 2013; Saczynski et al., 2012). This study focused, on a new nursing intervention aiming to facilitate participation from a family caregiver in the management of delirium. The study also focused on the validity of a new measure to monitor delirium, cerebral oximetry, a non-invasive measure potentially able to indicate the presence and severity of the delirium. The primary objective of the randomized pilot study was to assess the acceptability and feasibility of the design and nursing interventions, and the validity of cerebral oximetry to monitor delirium. The secondary objective was to assess the preliminary efficacy of the intervention. Thirty dyads including a patient who had post-cardiac surgery delirium and a family caregiver were randomly assigned to either the control group receiving the usual care or a group receiving the experimental nursing interventions. The intervention, rooted in a caring approach, aimed to facilitate family caregivers’ transition to an involved role in delirium management in addition to promoting the enhancement of their self-efficacy. The primary indicator to assess the acceptability of the design was the consent of at least 75 % of family caregivers who were approached to participate in the study. Afterwards, the acceptability and feasibility was were evaluated based on criteria in the field of pilot studies for the study design, for example, on recruitment data, and on criteria in the field of evaluation of nursing interventions for the intervention, for example, the satisfaction of the caregivers . The preliminary effects of the intervention of the patients were measured using a score reflecting delirium severity, the amount of postoperative complications as well as the length of hospital stay and patient’s psycho-functional recovery. Scores for anxiety and self-efficacy were also obtained from the caregivers. In order to test the validity of the new measure of delirium, cerebral oximetry values were compared to scores on three validated delirium rating scales. The primary indicator of the acceptability estimate was achieved with a 76.9 % consent rate among caregivers. However, recruitment has sown itself to be a great challenge, mainly because the number of eligible patients was less than anticipated. The experimental intervention was acceptable and feasible, as evidenced by the participation of the caregivers. Results on delirium severity and complications were similar in the two groups. Results favoring the intervention groups included shorter length of stay and less anxiety along with the added feeling of greater personal effectiveness among caregivers. In addition, a statistically significant effect of the intervention was observed on the psycho-functional recovery favoring the intervention group. (p=0.01). A statistically significant relationship between cerebral oximetry and occurrence and severity of delirium was observed (p ≤ 0.001), supporting the potential of this measure in monitoring the delirium. This study contributes to the advancements of knowledge through the demonstration of the acceptability and feasibility of an intervention to enhance the management of delirium by mentoring caregivers. Another contribution lies in the promising results on the validity of cerebral oximetry as a new monitoring measure of delirium, which has the potential of enhancing delirium detection and management.

Serious illness in childhood is a rare occurrence, but accounts for 20% of childhood deaths. Early recognition and treatment of serious illness is vital if the child is to recover without long-term disability. It is known that vital signs such as heart rate, respiratory rate, temperature, and oxygen saturation can be used to identify children who are at high risk of serious illness. This thesis presents research into the development of a vital signs monitor, designed for use in the initial assessment of unwell children at their first point of contact with a medical practitioner. Child-friendly monitoring techniques are used to obtain vital signs, which can then be combined using data fusion techniques to assist clinicians in identifying children with serious illness. Existing normal ranges for heart rate and respiratory rate in childhood vary considerably, and do not appear to be based on clinical evidence. This thesis presents a systematic meta-analysis of heart rate and respiratory rate from birth to 18 years of age, providing evidence-based curves which can be used to assess the degree of abnormality in these important vital signs. Respiratory rate is particularly difficult to measure in children, but is known to be predictive of serious illness. Current methods of automated measurement can be distressing, or are time-consuming to apply. This thesis therefore presents a novel method for estimating the respiratory rate from an optical finger sensor, the pulse oximeter, which is routinely used in clinical practice. Information from multiple vital signs can be used to identify children at risk of serious illness. A number of data fusion techniques were tested on data collected from children attending primary and emergency care, and shown to outperform equivalent existing scoring systems when used to identify those with more serious illness.

Opioid overdose is a growing epidemic plaguing the United States. Overdose related death has risen from 16,849 in 1999 to 69,029 in 2018. Almost 7 out of 10 of these deaths were due to opioids with 47% being caused by fentanyl or other synthetic opioids. There is a strong need to reduce the amount of overdose-related deaths. Indirect methods should be a first priority, and include counseling and care. For some individuals, this treatment option is unavailable because the drug user may not have the desire or economic means to pursue it. In this case, a more direct preventative approach is needed. This paper presents a novel method of detecting poor peripheral oxygenation, a biomarker linked to opioid overdose. A wristwatch near-infrared spectroscopy device (NIRS) was developed. SPICE simulations were conducted to confirm proper operation of electrical systems. The device was fabricated on a printed circuit board and mounted to a 3D printed enclosure. Absorbance of green, red and infrared (IR) light were measured. Additionally, peripheral capillary oxygen saturation (SpO2) modulation index and changes in concentration of oxyhemoglobin and deoxyhemoglobin were calculated from raw data. A brachial occlusion test was performed to mimic the effects of opioid overdose on peripheral oxygenation. A statistically significant difference (p < 0.05) was observed between pre-occlusion and during-occlusion groups in two subjects for measurement of peak-to-peak values of green raw data, red raw data, IR raw data, oxyhemoglobin concentration change, and deoxyhemoglobin concentration change. Peak-to-peak was observed as a consistent indicator of poor peripheral oxygenation and could serve as a useful metric in the detection of opioid overdose.

This thesis introduces the reader into RespiHeart, which is a product under development. RespiHeart is an complement/alternative to the regular Pulse Oximeter and is intended to be used within the health care sector for combined measurements and communication on open inexpensive platforms. This thesis evaluates interaction between RespiHeart and a Raspberry Pi 3 Model B to evaluate if the computer is capable of handling the data from RespiHeart and make signal processing. Python is used throughout the whole project and is a suitable language for interaction and signal processing in real time. / Detta examensarbete introducerar läsaren till RespiHeart, en ny trådlös produkt som är under utveckling. RespiHeart är ett komplement/alternativ till den nuvarande Pulsoximetern och är tänkt att användas inom sjukvården för analys, kommuniakation och kombinerade mätningar på öppna billiga plattformar. Detta project utvärderar interaktionen mellan RespiHeart och en Raspberry Pi 3 Model B för att undersöka om datorn är kapabel till att hantera datan från RespiHeart samt göra signal processing i real tid. Programmeringsspråket Python användes under hela projektet och är ett lämpligt språk att använda för interation och signal processing i real tid.