Mechanical ventilation (MV) is a life-saving therapy in acute respiratory distress syndrome (ARDS), a condition that affects 3000 patients/year in Sweden with a mortality rate of about 40%. However, MV may induce or worsen lung injury causing “ventilator-induced lung injury (VILI)”. From a mechanical perspective strain (deformation, or relative change in lung volume) and stress (tension) have been postulated as main determinants of VILI. High respiratory rate is potentially another factor that may exacerbate VILI by amplifying the total energy transmitted to the lungs during MV. In this thesis in animal ARDS models the hypotheses were that 1) lung parenchyma inhomogeneities concentrate stress and amplify lung damage and inflammation, 2) higher respiratory rates increase lung inflammation and lung edema in heterogeneous ARDS, and 3) local lung deformation is related to local inflammation. First, in a rat model the effect on inflammation and structural damage of regional lung collapse on the healthy surrounding lung tissue was assessed. Second, in porcine models the effect of respiratory rate on lung edema and inflammation was studied during two ventilatory modes; a) a permissive collapse mode and b) a homogenized lung parenchyma mode. Finally, lung deformation was correlated with lung inflammation assessed by positron emission tomography using 18F-FDG uptake. It was found that; 1) local inhomogeneities can act as stress amplifiers, increasing lung tissue inflammation and damage in the healthy surrounded lung. 2) high respiratory rate increases lung edema but decreases lung inflammation when permissive lung collapse is used and that these effects are prevented with lung parenchyma homogenization; 3) local lung deformation and inflammation are well correlated. In conclusion, lung inhomogeneities may aggravate VILI, respiratory rate may affect in different ways VILI progression depending on the ventilatory strategy, and finally, lung deformation is closely related to lung inflammation. With the caveat that the studies are performed in animal models, the results suggest that using ventilator strategies that homogenize the lungs, i.e., open collapsed lung regions and prevent re-collapse in ARDS will reduce VILI and in the end may decrease morbidity and the high mortality in this condition.

SAMMANFATTNING Sjuksköterskan tillämpar omvårdnadsprocessen genom att observera, värdera, prioritera, dokumentera och vid behov åtgärda och hantera förändringar i allmäntillståndet, samt motverka komplikationer i samband med sjukdom, vård och behandling. Andningsfrekvens (AF) är den vitalparameter som först förändras och signalerar en förändring i allmäntillståndet. Vid de flesta hjärtstopp på sjukhus finns tecken till försämring hos patienten redan några timmar eller upp till ett dygn före.  Syftet var att undersöka sjuksköterskans inställning och följsamhet till att mäta och bedöma AF hos akuta sjuka patienter, för att tidigt upptäcka en försämring i patientens hälsotillstånd. Genom en litteraturstudie framkom fyra teman. Rutiners betydelse, sjuksköterskans inställning till AF och varför den inte mättes, värdet av förändringsarbete samt möjliga arbetssätt för att undvika vårdskador. Rutiner för mätning av AF, olika poängsystem och mätmallar för bedömning av vitalparametrar, påverkade antalet mätningar och registreringar av AF. Den enskilda sjuksköterskans inställning inverkade på mätningen och bedömningen av AF. Flera anledningar till varför AF inte mättes fanns. Studier visade att förändringsarbete och implementering av nya arbetssätt var ett komplext område, insatser krävdes inom flera områden på olika nivåer. Vårdskador och plötslig oväntad död minskade när nya rutiner och arbetssätt kombinerades med utbildning, uppföljning och återkoppling till personalen. AF är en viktig vitalparameter. Används inte den kunskapen för att hitta patienter på väg att försämras, riskerar patienterna att drabbas av vårdskador. Ett utbildningsbehov finns, den senaste forskningen har påvisat att rätt genomförd implementering av övervakningsrutiner och förändrat arbetssätt kan ge ett bra utfall i minskat antal vårdskador och oförutsedd död. / ABSTRACT The nurse applies the nursing process by observing, evaluating, prioritising, documenting and when necessary manage changes in the condition of the patient, and to prevent complications associated with disease, care and treatment. Respiratory Rate (RR) is the vital sign that first changes and signals changes in a patient’s condition. In most cardiac arrests there are signs of deterioration of the patient a few hours up to a day before the event.    The aim of this study was to investigate the nurse´s attitude and adherence to measure and assess RR in acutely ill patients, for an early detection of deterioration in the patient's state of health. Through a literature study four themes were emerged. The importance of guidelines, the nurses' attitude and why the RR was not measured, the value of change of management and possible ways to avoid injuries. Guidelines for the measurement of RR, different scoring systems and observations charts for the assessment of vital signs all affected the measuring and scorings of RR. The individual nurse's attitude affected the measurement and assessment of RR. Several reasons why RR was not measured were found. The studies showed that the process of change and implementation of new ways of working is a complex, and efforts were needed in several areas and at different levels. Care injuries and sudden unexpected deaths decreased when new routines and working procedures were combined with training, monitoring and feedback to the staff.   Research shows that RR is an important vital sign. If this knowledge is not used to find patients about to deteriorate, these patients risk suffering from permanent health effects. There is a need for significant training in this area and recent research has shown that a correct implementation of the procedures provide a good outcome in a decreased number of medical injuries and unexpected death

Le photopléthysmogramme (PPG) est un signal optique acquis à partir de l’oxymètre de pouls, dont l’usage principal consiste à mesurer la saturation en oxygène. Avec le développement des technologies portables, il est devenu la technique de base pour la surveillance de l’activité cardio-respiratoire des patients et la détection des anomalies. En dépit de sa simplicité d'utilisation, le déploiement de cette technique reste encore limité pour deux principales raisons : 1. L’extrême sensibilité du signal aux distorsions. 2. La non-reproductibilité entre les sujets et pour les mêmes sujets, en raison de l'âge et des conditions de santé. L’objectif de cette thèse est le développement de méthodes robustes et universelles afin d’avoir une estimation précise de la fréquence respiratoire (FR) indépendamment de la variabilité intra et interindividuelle du PPG. Plusieurs contributions originales en traitement statistiques du signal PPG sont proposées. En premier lieu, une méthode adaptative de détection des artefacts basée sur la comparaison de modèle a été développée. Des tests par la technique Random Distortion Testing sont introduits pour détecter les pulses de PPG avec des artefacts. En deuxième lieu, une analyse de plusieurs méthodes spectrales d’estimation de la FR est proposée. Afin de mettre en évidence la robustesse des méthodes proposées face à la variabilité du signal, plusieurs tests ont été effectués sur deux bases de données avec de différentes tranches d'âge et des différents modes respiratoires. En troisième lieu, un indice de qualité respiratoire spectral (SRQI) est conçu dans le but de communiquer au clinicien que les valeurs fiables de la FR avec un certain degré de confiance. / One promising area of research in clinical routine involves using photoplethysmography (PPG) for monitoring respiratory activities. PPG is an optical signal acquired from oximeters, whose principal use consists in measuring oxygen saturation. Despite its simplicity of use, the deployment of this technique is still limited because of the signal sensitivity to distortions and the non-reproducibility between subjects, but also for the same subject, due to age and health conditions. The main aim of this work is to develop robust and universal methods for estimating accurate respiratory rate regardless of the intra- and inter-individual variability that affects PPG features. For this purpose, firstly, an adaptive artefact detection method based on template matching and decision by Random Distortion Testing is introduced for detecting PPG pulses with artefacts. Secondly, an analysis of several spectral methods for Respiratory Rate (RR) estimation on two different databases, with different age ranges and different respiratory modes, is proposed. Thirdly, a Spectral Respiratory Quality Index (SRQI) is attributed to respiratory rate estimates, in order that the clinician may select only RR values with a large confidence scale. Promising results are found for two different databases.

A goiaba vermelha é pouco conhecida pelos mercados importadores, porém tem um potencial de comercialização bastante grande, pois a goiaba é considerada um dos frutos mais completos em termos nutricionais. Porém, a presença de moscas-das-frutas nos frutos leva países importadores a impor restrições comerciais por motivos fitossanitários. Os EUA permitem que a irradiação seja utilizada para controle quarentenário de Anastrepha spp. E Ceratitis capitata, com dose mínima de 150 Gy e 225 Gy, respectivamente. Como existe variação de dose dentro do container irradiado, que pode ser de 1:3, frutos deverão apresentar qualidade comercial mesmo quando submetidos a doses até três vezes maiores que a dose mínima de controle. Portanto, este trabalho verificou a qualidade de goiabas Pedro Sato irradiadas com 150 e 450 Gy e, também, com 225 e 675 Gy que representam as doses mínimas e máximas para controle quarentenário de Anastrepha spp. e C. Capitata, respectivamente. No primeiro experimento, goiabas foram irradiadas com 0, 150, 225, 450, 675 Gy e avaliadas a 0, 2, 4 e 6 dias após a irradiação para as análises físico-químicas. As determinações de incidência de doenças e escurecimento da casca, taxa respiratória e produção de etileno foram realizadas diariamente. As análises sensoriais ocorreram 5 dias após irradiação, sendo que as organolépticas foram irradiadas com 0, 225 e 675 Gy. As goiabas deste experimento foram armazenadas a 23 mais ou menos 1oC e 85 mais ou menos 5% UR. Os resultados indicaram que a irradiação acelerou o amadurecimento das goiabas, predispôs os frutos a doenças e favoreceu a perda de massa. A taxa respiratória e a produção de etileno foram maiores para os frutos irradiados até o quarto dia de armazenagem. Em relação às análises sensoriais, foi verificada qualidade organoléptica superior dos frutos não irradiados. No segundo experimento as doses aplicadas foram idênticas ao primeiro experimento. Goiabas foram armazenadas sob temperatura de refrigeração (TR) de 10 mais ou menos 1oC e 80 mais ou menos 5% UR e analisadas a 0, 7 e 14 dias, sendo que aos 7 e 14 dias as goiabas foram transferidas à temperatura ambiente (TA) de 23 mais ou menos 1oC e 70 mais ou menos 5% UR durante dois dias quando foram novamente analisadas. As análises sensoriais foram realizadas nas goiabas armazenadas por 7 e 14 dias a TR + 2 a TA. Os resultados demonstram que goiabas irradiadas armazenadas por 7 dias a TR + 2 a TA estavam amolecidas e as irradiadas com 450 e 675 Gy apresentaram coloração interna menos intensa. Além destas alterações, frutos irradiados armazenados por 14 dias a TR + 2 a TA apresentaram incidência de casca escurecida e maior perda de massa. Em relação às análises sensoriais, goiabas irradiadas armazenadas por 7 dias a TR + 2 a TA apresentaram qualidade organoléptica aceitável, embora inferior às não irradiadas. Já as goiabas armazenadas por 14 dias a TR + 2 a TA apresentaram qualidade inaceitável quando irradiadas com 675 Gy, enquanto que as não irradiadas e as irradiadas com 225 Gy foram apenas um pouco superiores ao limite aceitável / Red guava is not a well-known fruit by importing markets; however, it has a great commercial potential, since it is considered one of the most complete fruits in terms of nutritional quality. However, the presence of fruit-flies in fruits leads importing countries to impose commercial restrictions due to phytosanitary risk. The USA permit the use of irradiation to the quarantine control of Anastrepha spp. and Ceratitis Capitata with a minimum dose of 150 and 225 Gy, respectively. Since, there is a dose variation inside na irradiated container, which can be of 1:3, fruits must present commercial quality, even after irradiation with doses of up to three times higher than the minimum required dose. Therefore this works objective was the study of the quality of Pedro Sato guavas irradiated with 150 and 450 Gy and, also, 225 and 675 Gy, which represented minimum and maximum doses of quarantine control of Anastrepha spp. and C. capitata, respectively. In the first experiment, guavas were irradiated with 0, 150, 225, 450, 675 Gy and evaluated at 0, 2, 4 e 6 days after irradiation for the physic-chemical analysis. The determinations of disease incidence, peel darkening incidence, respiration rate and ethylene production was done in a daily basis. The sensory assessments took place 5 days after irradiation, in which the organoleptic assessments were irradiated with 0, 225 e 675 Gy. Guavas during this experiment were stored at 23 more or less 1oC e 85 more or less 5% RH. The results indicate that irradiation speeded up the ripening of guavas, increased disease incidence and mass loss. The respiratory rate and ethylene production was higher to the irradiated fruits until the fourth day of storage. In relation to the sensory analysis, superior organoleptic quality was found in non-irradiated fruits. In the second experiment, applied doses were identical to the ones of the firs experiment. Guavas were stored under refrigerated temperature (RT) at 10 more or less 1oC and 80 more or less 5% UR and analyzed at 0, 7 and 14 days; at 7 e 14 days guavas were transferred to ambient temperature (AT) of 23 more or less 1oC and 70 more or less 5% UR during two days to be analyzed again. Sensory analysis were made in guavas stored for 7 and 14 days at RT + 2 at AT. The results showed that irradiated guavas stored by 7 days at RT + 2 at AT were softened and the ones irradiated with 450 e 675 Gy presented pulp color less intense. In addition to these alterations irradiated guavas stored for 14 days at RT + 2 at AT presented incidence of peel darkening and higher mass loss. In relation to the sensory analysis, irradiated guavas stored for 7 days at RT + 2 at AT presented acceptable organoleptic quality, although inferior to the non-irradiated ones. In the other hand, guavas stored for 14 days at RT + 2 a AT presented unacceptable quality when irradiated with 675 Gy, whereas the non-irradiated and the irradiated with 225 Gy were only barely acceptable

No description available.

Current monitoring tools in the intensive care units focus on displaying physiologically monitored parameters (e.g. vital signs such as heart rate, respiratory rate and blood pressure) at the present moment. Added clinical utility can be found by analyzing how the conditions of a patient evolve with time, and automatically relating that dynamics to population trends. Variability analysis consists of monitoring patterns of variation over intervals in time of physiological signals such as heart rate and respiratory rate. Given that illness has been associated in multiple studies with altered variability, most commonly lack of variation, variability monitoring represents a tool whose contribution at the bedside still needs to be explored. With the long term objective of improving care, this thesis promotes the use of variability analysis through three distinct types of analysis: facing the technical challenges involved with the dimensionality of variability analysis, enhancing the physiological understanding of variability, and showing its utility in real world clinical applications. In particular, the contributions of this thesis include: the review and classification into domains of a large array of measures of variability; the design of system and methods to integrate multiple measures of variability into a unique score, called composite measure, bringing relevant information to specific clinical problems; the comparison of patterns of heart rate variability during exercise and sepsis development, showing the inability of single measures of variability to discriminate between the two kinds of stressors; the analysis of variability produced from a physiologically-based model of the cardiovascular system, showing that each single measure of variability is an unspecific sensor of the body, thereby promoting multivariate analysis to the only means of understanding the physiology underlying variability; the study of heart rate variability in a population at high risk of sepsis development, showing the ability of variability to predict the occurrence of sepsis more than 48 hours in advance respect to the time of diagnosis of the clinical team; the study of heart and respiratory rate variability in intubated intensive care unit patients, showing how variability can provide a better way of assessing extubation readiness respect to commonly used clinical parameters. Overall, it is hoped that these novel contributions will help promoting bedside applications of variability monitoring to improve patient care.

A goiaba vermelha é pouco conhecida pelos mercados importadores, porém tem um potencial de comercialização bastante grande, pois a goiaba é considerada um dos frutos mais completos em termos nutricionais. Porém, a presença de moscas-das-frutas nos frutos leva países importadores a impor restrições comerciais por motivos fitossanitários. Os EUA permitem que a irradiação seja utilizada para controle quarentenário de Anastrepha spp. E Ceratitis capitata, com dose mínima de 150 Gy e 225 Gy, respectivamente. Como existe variação de dose dentro do container irradiado, que pode ser de 1:3, frutos deverão apresentar qualidade comercial mesmo quando submetidos a doses até três vezes maiores que a dose mínima de controle. Portanto, este trabalho verificou a qualidade de goiabas Pedro Sato irradiadas com 150 e 450 Gy e, também, com 225 e 675 Gy que representam as doses mínimas e máximas para controle quarentenário de Anastrepha spp. e C. Capitata, respectivamente. No primeiro experimento, goiabas foram irradiadas com 0, 150, 225, 450, 675 Gy e avaliadas a 0, 2, 4 e 6 dias após a irradiação para as análises físico-químicas. As determinações de incidência de doenças e escurecimento da casca, taxa respiratória e produção de etileno foram realizadas diariamente. As análises sensoriais ocorreram 5 dias após irradiação, sendo que as organolépticas foram irradiadas com 0, 225 e 675 Gy. As goiabas deste experimento foram armazenadas a 23 mais ou menos 1oC e 85 mais ou menos 5% UR. Os resultados indicaram que a irradiação acelerou o amadurecimento das goiabas, predispôs os frutos a doenças e favoreceu a perda de massa. A taxa respiratória e a produção de etileno foram maiores para os frutos irradiados até o quarto dia de armazenagem. Em relação às análises sensoriais, foi verificada qualidade organoléptica superior dos frutos não irradiados. No segundo experimento as doses aplicadas foram idênticas ao primeiro experimento. Goiabas foram armazenadas sob temperatura de refrigeração (TR) de 10 mais ou menos 1oC e 80 mais ou menos 5% UR e analisadas a 0, 7 e 14 dias, sendo que aos 7 e 14 dias as goiabas foram transferidas à temperatura ambiente (TA) de 23 mais ou menos 1oC e 70 mais ou menos 5% UR durante dois dias quando foram novamente analisadas. As análises sensoriais foram realizadas nas goiabas armazenadas por 7 e 14 dias a TR + 2 a TA. Os resultados demonstram que goiabas irradiadas armazenadas por 7 dias a TR + 2 a TA estavam amolecidas e as irradiadas com 450 e 675 Gy apresentaram coloração interna menos intensa. Além destas alterações, frutos irradiados armazenados por 14 dias a TR + 2 a TA apresentaram incidência de casca escurecida e maior perda de massa. Em relação às análises sensoriais, goiabas irradiadas armazenadas por 7 dias a TR + 2 a TA apresentaram qualidade organoléptica aceitável, embora inferior às não irradiadas. Já as goiabas armazenadas por 14 dias a TR + 2 a TA apresentaram qualidade inaceitável quando irradiadas com 675 Gy, enquanto que as não irradiadas e as irradiadas com 225 Gy foram apenas um pouco superiores ao limite aceitável / Red guava is not a well-known fruit by importing markets; however, it has a great commercial potential, since it is considered one of the most complete fruits in terms of nutritional quality. However, the presence of fruit-flies in fruits leads importing countries to impose commercial restrictions due to phytosanitary risk. The USA permit the use of irradiation to the quarantine control of Anastrepha spp. and Ceratitis Capitata with a minimum dose of 150 and 225 Gy, respectively. Since, there is a dose variation inside na irradiated container, which can be of 1:3, fruits must present commercial quality, even after irradiation with doses of up to three times higher than the minimum required dose. Therefore this works objective was the study of the quality of Pedro Sato guavas irradiated with 150 and 450 Gy and, also, 225 and 675 Gy, which represented minimum and maximum doses of quarantine control of Anastrepha spp. and C. capitata, respectively. In the first experiment, guavas were irradiated with 0, 150, 225, 450, 675 Gy and evaluated at 0, 2, 4 e 6 days after irradiation for the physic-chemical analysis. The determinations of disease incidence, peel darkening incidence, respiration rate and ethylene production was done in a daily basis. The sensory assessments took place 5 days after irradiation, in which the organoleptic assessments were irradiated with 0, 225 e 675 Gy. Guavas during this experiment were stored at 23 more or less 1oC e 85 more or less 5% RH. The results indicate that irradiation speeded up the ripening of guavas, increased disease incidence and mass loss. The respiratory rate and ethylene production was higher to the irradiated fruits until the fourth day of storage. In relation to the sensory analysis, superior organoleptic quality was found in non-irradiated fruits. In the second experiment, applied doses were identical to the ones of the firs experiment. Guavas were stored under refrigerated temperature (RT) at 10 more or less 1oC and 80 more or less 5% UR and analyzed at 0, 7 and 14 days; at 7 e 14 days guavas were transferred to ambient temperature (AT) of 23 more or less 1oC and 70 more or less 5% UR during two days to be analyzed again. Sensory analysis were made in guavas stored for 7 and 14 days at RT + 2 at AT. The results showed that irradiated guavas stored by 7 days at RT + 2 at AT were softened and the ones irradiated with 450 e 675 Gy presented pulp color less intense. In addition to these alterations irradiated guavas stored for 14 days at RT + 2 at AT presented incidence of peel darkening and higher mass loss. In relation to the sensory analysis, irradiated guavas stored for 7 days at RT + 2 at AT presented acceptable organoleptic quality, although inferior to the non-irradiated ones. In the other hand, guavas stored for 14 days at RT + 2 a AT presented unacceptable quality when irradiated with 675 Gy, whereas the non-irradiated and the irradiated with 225 Gy were only barely acceptable

Current monitoring tools in the intensive care units focus on displaying physiologically monitored parameters (e.g. vital signs such as heart rate, respiratory rate and blood pressure) at the present moment. Added clinical utility can be found by analyzing how the conditions of a patient evolve with time, and automatically relating that dynamics to population trends. Variability analysis consists of monitoring patterns of variation over intervals in time of physiological signals such as heart rate and respiratory rate. Given that illness has been associated in multiple studies with altered variability, most commonly lack of variation, variability monitoring represents a tool whose contribution at the bedside still needs to be explored. With the long term objective of improving care, this thesis promotes the use of variability analysis through three distinct types of analysis: facing the technical challenges involved with the dimensionality of variability analysis, enhancing the physiological understanding of variability, and showing its utility in real world clinical applications. In particular, the contributions of this thesis include: the review and classification into domains of a large array of measures of variability; the design of system and methods to integrate multiple measures of variability into a unique score, called composite measure, bringing relevant information to specific clinical problems; the comparison of patterns of heart rate variability during exercise and sepsis development, showing the inability of single measures of variability to discriminate between the two kinds of stressors; the analysis of variability produced from a physiologically-based model of the cardiovascular system, showing that each single measure of variability is an unspecific sensor of the body, thereby promoting multivariate analysis to the only means of understanding the physiology underlying variability; the study of heart rate variability in a population at high risk of sepsis development, showing the ability of variability to predict the occurrence of sepsis more than 48 hours in advance respect to the time of diagnosis of the clinical team; the study of heart and respiratory rate variability in intubated intensive care unit patients, showing how variability can provide a better way of assessing extubation readiness respect to commonly used clinical parameters. Overall, it is hoped that these novel contributions will help promoting bedside applications of variability monitoring to improve patient care.

This study examined the relationship between lung capacity, speech volume and duration of utterances. 8 adult subjects, 4 males and 4 females (24-36 yrs), participated. By breathing into a digital spirometer, lung capacities such as Vital Capacity (VC) and Inspirational Capacity (IC) were estimated. Respiratory movements were measured using Respiratory Inductance Plethysmography (RIP), and these respiratory movements were calibrated in litres using the spirometer. The proportion of lung capacity used for speech was estimated from the calibrated RIP signals during reading of a nonsense text without punctuation marks. This proportion was defined as the median volume of exhaled air per utterance (SV) (in litres) during text reading, divided by the speaker’s VC (SV/VC). Utterance durations (UD) and Respiratory Rates (RR) were estimated from acoustic recordings of the text readings as well as the RIP signals, displayed in Praat. This allowed investigating the relationships between lung capacity, respiratory rate, utterance durations as well as the proportion of lung capacity used for speech. Put differently, the question was whether people with larger lungs speak in longer utterances and inhale less frequently, as well as whether people with smaller lungs use a relatively larger proportion of their lung capacity for speaking. Additionally, where SV initiated (SVIN) and terminated (SVTER) within VC was calculated based on the RIP signals. There were no significant relationships between VC and UD or RR. In addition, there was no significant relationship between SV/VC and VC. SVIN ranged from 43%-71% and SVTER ranged from 17%-55%. The results indicate no relationship between VC and UD or RR nor that people with a smaller VC use more of it for speech. The range of SV within VC suggest that people maintain a fairly relaxed state with regards to muscle pressure.

Ce mémoire de thèse vise à proposer de nouvelles méthodes robustes pour l'estimation de la fréquence respiratoire (FR) à partir des signaux physiologiques souvent utilisés dans la clinique comme l'électrocardiogramme (ECG) ou le photoplethysmogramme (PPG), tout en évitant de porter des capteurs encombrants et inconfortables. En effet, la respiration influence les signaux ECG et/ou PPG. Plusieurs modulations qui décrivent la respiration sont extraites basée principalement sur l'amplitude, la fréquence et la ligne de base. Il est toutefois difficile de déterminer la combinaison optimale des modulations pour obtenir une estimation précise de la FR en raison du bruit, la spécificité de chaque patient et de l'activité. Après une revue de la littérature, il ressort que peu de travaux ont étudié la qualité de ces modulations. Nous proposons donc de quantifier la qualité des modulations à l'aide d'indices de qualité respiratoire (IQR), un nouvel indice basé sur une modulation sinusoïdale est introduit. Puis, deux méthodes sont proposées: la première sélectionne automatiquement la modulation avec l'IQR le plus élevé pour une estimation de la FR, la seconde combine les deux meilleurs modulations avec le lisseur de Kalman (LK). Une nouvelle approche de fusion de modulations basée sur un modèle multimodale est également explorée. Ces méthodes sont évaluées sur trois bases de données de différents contextes cliniques: la surveillance dans les soins postopératoires (où les patients sont immobiles), le suivi pendant les activités physiques quotidiennes et la surveillance néonatale. Les résultats expérimentaux montrent que les IQRs associés à un algorithme de fusion augmentent la précision de l'estimation de la FR à partir des modulations dérivées et montrent des résultats supérieurs aux travaux issus de la littérature. / The presented work in this dissertation concerns the development of approaches to estimate the breathing rate (BR) accurately from the electrocardiogram (ECG) and photoplethysmogram (PPG), to avoid wearing cumbersome and uncomfortable sensors for direct measurements. In fact, the respiration influences ECG and PPG signals. Several modulations are extracted to describe breathing cycles based on amplitude, frequency and baseline. However, it is difficult to determine the optimal combination to estimate the BR due to the noise and patient-dependency. Since few works have studied the quality of these modulations, we propose to study the quality of modulations using respiratory quality indices (RQI). To do so, we present two methods: the first automatically selects the modulations with the highest RQI for BR estimation, the second tracks the respiration signal using Kalman smoother. The obtained results show superior performance comparing to the methods in the literature. In addition, an extension of fusion approach is presented based on a multi-mode model. These proposed methods are tested on several datasets with different clinical contexts: monitoring post-operative care (where patients are immobile), daily physical activities and neonatal monitoring. The experimental results show that the RQIs coupled with a fusion algorithm increase the accuracy of the BR estimation from the derived modulations.