Pulse oximetry is used to measure heart rate (HR) and arterial oxygen saturation (SpO2) from photoplethysmographic (PPG) waveforms. PPG waveforms are highly sensitive to motion artifact (MA), limiting the implementation of pulse oximetry in mobile physiological monitoring using wearable devices. Previous studies have shown that multichannel pulse oximetry can successfully acquire diverse signal information during simple, repetitive motion, thus leading to differences in motion tolerance across channels. In this study, we introduce a multichannel forehead-mounted pulse oximeter and investigate the performance of this novel sensor under a variety of intense motion artifacts. We have developed a multichannel template-matching algorithm that chooses the channel with the least amount of motion artifact to calculate HR and SpO2 every 2 seconds. We show that for a wide variety of random motion, channels respond differently to motion, and the multichannel estimate outperforms single channel estimates in terms of motion tolerance, signal quality, and HR and SpO2 error. Based on 31 data sets of PPG waveforms corrupted by random motion, the mean relative HR error was decreased by an average of 5.6 bpm when the multichannel-switching algorithm was compared to the worst performing channel. The percentage of HR measurements with absolute errors ≤ 5 bpm during motion increased by an average of 27.8 % when the multichannel-switching algorithm was compared to the worst performing channel. Similarly, the mean relative SpO2 error was decreased by an average of 4.3 % during motion when the multichannel-switching algorithm was compared to each individual channel. The percentage of SpO2 measurements with absolute error ≤ 3 % during motion increased by an average of 40.7 % when the multichannel-switching algorithm was compared to the worst performing channel. Implementation of this multichannel algorithm in a wearable device will decrease dropouts in HR and SpO2 measurements during motion. Additionally, the differences in motion frequency introduced across channels observed in this study shows precedence for future multichannel-based algorithms that make pulse oximetry measurements more robust during a greater variety of intense motion.

O monitoramento automático de pacientes é um recurso essencial em hospitais para o bom gerenciamento de cuidados médicos. Enquanto que alarmes devido a condições fisiológicas anormais são importantes para o rápido tratamento, estes também podem ser uma fonte de ruídos desnecessários devido a falsos alarmes causados por interferência eletromagnética ou movimentação de sensores. Uma fonte significativa de falsos alarmes é relacionada com a frequência cardíaca, o qual é disparado quando o ritmo cardíaco do paciente está muito rápido ou muito lento. Neste trabalho, a fusão de diferentes sensores fisiológicos é explorada para fazer uma estimativa robusta de frequência cardíaca. Um conjunto de algoritmos utilizando índice de variabilidade cardíaca, inferência bayesiana, redes neurais, lógica fuzzy e votador majoritário são propostos para fundir a informação do eletrocardiograma, pressão sanguínea e fotopletismograma. Três informações básicas são extraídas de cada sensor: variabilidade cardíaca, a diferença de frequência cardíaca entre os sensores e a análise espectral. Estas informações são usadas como entradas para os algoritmos. Quarenta gravações selecionadas do banco de dados MIMIC são usadas para validar o sistema. Finalmente, a frequência cardíaca calculada é comparada com as anotações do banco de dados. Resultados mostram que a fusão utilizando redes neurais apresenta a melhor redução de falsos alarmes de 89.33%, enquanto que a técnica bayesiana apresenta uma redução de 83.76%. A lógica fuzzy mostrou uma redução de 77.96%, o votador majoritário 61.25% e o índice de variabilidade cardíaca de 65.43%. Portanto, os algoritmos propostos mostraram bom desempenho e podem ser muito úteis em monitores de sinais vitais modernos. / Automatic patient monitoring is an essential resource in hospitals for good health care management. While alarms due to abnormal physiological conditions are important to deliver fast treatment, it can be also a source of unnecessary noise due to false alarms caused by electromagnetic interference or motion artifacts. One significant source of false alarms are those related to heart rate, which is triggered when the heart rhythm of the patient is too fast or too slow. In this work, the fusion of different physiological sensors is explored in order to create a robust heart rate estimation. A set of algorithms using heart rate variability index, bayesian inference, neural networks, fuzzy logic and majority voting is proposed to fuse information from electrocardiogram, arterial blood pressure and photoplethysmogram. Three basic informations are extracted from each source, namely, heart rate variability, the heart rate difference between sensors and the spectral analysis. These informations are used as inputs to the algorithms. Forty selected recordings from MIMIC database was used to validate the system. Finally, the calculated heart rate is compared with the database annotation. Results show that neural networks fusion presents the best false alarms reduction of 89.33%, while the bayesian technique presents an error reduction of 83.76%. Fuzzy logic showed an error reduction of 77.96%, majority voting 61.25% and the heart rate variability index 65.43%. Therefore, the proposed algorithms showed good performance and can be very useful for modern bedside monitors.

Introdução: o trabalho do policial é complexo e permeado de estresse que, quando associado a hábitos de vida nocivos, aumenta o risco de danos cardiocirculatórios. A crescente onda de violência urbana e o frequente confronto com vândalos expõem os policiais a maior risco de estresse e morte. Objetivo: este estudo tem como objetivo analisar o efeito de uma intervenção educativa de enfermagem (IEE) nos índices da variabilidade da frequência cardíaca em policiais de um Batalhão Militar de Santa Catarina. Método: trata-se de um estudo experimental do tipo antes e depois com um único grupo de abordagem quantitativa com 38 policiais militares do sexo masculino no período de fevereiro a junho de 2016. As variáveis independentes foram compostas por qualidade de vida e estratégias de coping que foram coletadas por meio das escalas de avaliação da qualidade de vida (WHOQOL-Bref) e da escala para avaliar as estratégias de enfrentamento (Coping). Considerou-se variável dependente a variabilidade da frequência cardíaca (VFC). A mensuração da VFC deu-se por meio de método linear, no domínio de tempo e frequência durante quinze minutos. O estresse foi mensurado por meio da variação da concentração de cortisol salivar, com amostras de saliva coletadas individualmente em três horários: ao acordar, 30 minutos após acordar e antes de dormir. Essas medidas foram realizadas no início e ao término das sessões de intervenção educativa. O programa Statistical Package for the Social Sciences foi utilizado para as análises estatísticas descritivas. Os dados foram analisados por meio de medidas de tendência central. A normalidade da distribuição foi analisada pelos testes de Shapiro-Wilk e Kolmogorov-Smirnov. Para comparar as variáveis antes e após a intervenção educativa, usou-se o teste t-Student para amostras pareadas; em caso de assimetria, o teste de Wilcoxon. Para avaliar a associação das variáveis contínuas e ordinais com as variáveis de desfecho após a intervenção, foi aplicado o coeficiente de correlação de Spearman. Foram considerados significativos os dados com valor de p bicaudal menor ou igual a 0,05. Resultados: os policiais militares apresentavam idade média de 30,4 anos (±5,6), trabalhavam há quatro anos na instituição, e 34,2% apresentaram problemas de saúde. Os valores médios de pressão arterial se encontravam dentro da normalidade (123 mmHg x 80,1mmHg), entretanto o Índice de Massa Corporal indica sobrepeso (25,5±2,7 Kg/m²) e o Índice de Adiposidade Cutânea mostra 17,95% de gordura acima da média. Em relação à qualidade de vida, os domínios Físico (p=0,002), Meio Ambiente (p=0,039) e Percepção Global de Qualidade de Vida (PGQV) (p=0,002) do WHOQOL-Bref apresentaram medias superiores após a IEE, enquanto a estratégia de coping reduziu (p=0,042). Houve diferenças nas medianas de cortisol após a IEE. Aumentou ao acordar (p= <0,001), indicando melhora do sono; reduziu antes de dormir (p=0,047), como é esperado; na área abaixo da curva (p=0,007), que representa o cortisol total do período, e na resposta de cortisol ao acordar, indicando a expectativa de que o dia está sob mais controle; aumentou também a inclinação da reta (p<0,001), indicando diminuição dos valores de cortisol ao longo do dia. Na variabilidade da frequência cardíaca, a relação Low Frequency/High Frequency (LF/HF) reduziu (p=0,002), podendo indicar maior atividade parassimpática com balanço simpato-vagal sobre o coração. A concentração do cortisol à noite foi associada positivamente ao domínio Psicológico (0,402) e à Percepção Global de Qualidade de Vida (PGQV) (0,382) da escala WHOQOL-Bref. A área abaixo da curva (AUC) do cortisol teve relação estatística com o domínio Psicológico (0,330). A inclinação da reta de cortisol associou-se positivamente com a PGQV (0,411), enquanto a Resposta de Cortisol ao acordar teve associação positiva com a frequência cardíaca LF/HF (0,361). E ainda se observou melhora das médias na escala de alimentação após a intervenção (p<0,001), demonstrando melhora global nos hábitos alimentares. Conclusão: a intervenção educativa de enfermagem obteve efeito benéfico sobre a saúde dos policiais, com melhora em todos os domínios de qualidade de vida, com menor utilização das estratégias nocivas de enfrentamento Fuga-Esquiva, Afastamento e Confronto, além da melhora dos hábitos alimentares, repercutindo no aumento da variabilidade da frequência cardíaca e na redução da concentração de cortisol salivar. Tais intervenções/medidas podem ser úteis na prevenção de adoecimento por doenças cardiocirculatórias decorrentes de respostas fisiológicas ao estresse. / Introduction: the work of the policeman is complex and permeated with stress, which, when associated with harmful living habits, increases the risk of cardiocirculatory damage. The growing tide of urban violence and the frequent confrontation with vandals expose the policemen to a higher risk of stress and death. Objective: this study intends to analyze the effect of an educational nursing intervention (ENI) on the indexes of heart rate variability in policemen of a Military Battalion in Santa Catarina. Method: this is an experimental before-and-after study with a single group, with a quantitative approach, involving 38 male military police officers in the period from February to June 2016. The independent variables were composed of quality of life and coping strategies that were collected through the quality of life assessment scales (WHOQOL-Bref) and the scale for assessing coping strategies. Heart rate variability (HRV) was considered as a dependent variable. The HRV measurement took place by means of the linear method, in the domain of time and frequency for fifteen minutes. Stress was measured by means of the concentration variation of salivary cortisol, with samples of saliva individually collected on three different schedules: when waking up, 30 minutes after waking up and before sleeping. These measures were performed at the beginning and at the end of the educational intervention sessions. The Statistical Package for the Social Sciences program was used for the descriptive statistical analyzes. The data were analyzed by means of measures of central tendency. The distribution normality was analyzed through the Shapiro-Wilk and Kolmogorov-Smirnov tests. In order to compare the variables before and after the educational intervention, the t-Student test was used for paired samples; in case of asymmetry, the Wilcoxon test was used. In order to assess the association of the continuous and ordinal variables with the outcome variables after the intervention, the Spearman correlation coefficient was applied. The data with a two-tailed p value less than or equal to 0.05 were considered significant. Results: military police officers had an average age of 30.4 years (±5.6), worked for four years in the institution, and 34.2% showed health problems. The average blood pressure values were within the normal parameters (123 mmHg x 80,1mmHg), but the Body Mass Index indicates overweight (25.5±2.7 Kg/m²) and the Cutaneous Adiposity Index shows a fat percentage of 17.95% above average. Regarding the quality of life, the WHOQOL-Bref domains Physical (p=0.002), Environment (p=0.039) and Global Perceived Quality of Life (QOL) (p=0.002) showed higher averages after ENI, while the coping strategy decreased (p=0.042). There were differences in the medians of cortisol after ENI. It increased when waking up (p = <0.001), indicating improvement of sleep; decreased before sleeping (p=0.047), as expected; in the area below the curve (p=0.007), which represents the total cortisol of the period, and in the cortisol response when waking up, indicating the expectation that the day is under more control; it also increased the slope of the line (p<0.001), indicating decrease of cortisol values throughout the day. As for the heart rate variability, the Low Frequency/High Frequency (LF/HF) ratio decreased (p=0.002), which may indicate higher parasympathetic activity with a sympathovagal balance on the heart. The cortisol concentration at night was positively associated with the Psychological domain (0.402) and with the Global Perceived Quality of Life (QOL) (0.382) of the WHOQOL-Bref scale. The area below the cortisol curve (AUC) had a statistical relationship with the Psychological domain (0.330). The slope of the cortisol line was positively associated with QOL (0.411), while the Cortisol Response was positively associated with the LF/HF heart rate (0.361). There was also an improvement in the averages in the feeding scale after the intervention (p <0.001), demonstrating a global improvement in the dietary habits. Conclusion: the nursing educational intervention has obtained a beneficial effect on the health of the policemen, with improvements in all domains of quality of life and less use of the harmful coping strategies related to Escape-Avoidance, Distance and Confrontation, besides the improvement of dietary habits, reverberating in the increased heart rate variability and in the decreased salivary cortisol concentration. Such interventions/measures may be useful in preventing illness due to cardiocirculatory diseases arising from physiological responses to stress.

O objetivo deste estudo foi investigar as contribuições dos sistemas energéticos e do gasto energético total em situação de luta. A amostra foi composta de 10 atletas do sexo masculino de nível nacional/internacional (21±6 anos; 176.2±5.3cm; 67.2±9.0kg), competindo em nível internacional. Para a estimativa das contribuições energéticas e do gasto energético total, foram realizados três protocolos simulando combate (um round, dois rounds e três rounds). As lutas foram filmadas para quantificação das ações motoras em cada round. A estimativa dos sistemas energéticos aeróbio (WAER), anaeróbio alático (WPCR) e anaeróbio lático (W[La-]) foi realizada através do consumo de oxigênio durante a atividade, do delta da concentração sanguínea de lactato de cada round e do débito alático de oxigênio (DAO2), respectivamente. A razão entre as ações de elevada intensidade e momentos de baixa intensidade (step e pausa) no protocolo 3 foi ~1:7. Os resultados dos sistemas WAER, WPCR e W[La-] no protocolo 3 foi 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectivamente. Assim, as sessões de treinamento devem ser direcionadas principalmente para a melhoria do sistema anaeróbio alático (responsável pelas ações de alta intensidade), e do sistema aeróbio (responsável pelo processo de recuperação entre as ações de alta intensidade) / The purpose of this study was to investigate energy system contributions and energy cost in combat situation. The sample was constituted by 10 male taekwondo athletes at national/international level (age: 21±6 years old; height: 176.2±5.3cm; body mass: 67.2±9.0kg) competing at national/international level. To estimate the energy contributions and total energy cost of the fights, athletes performed a three different protocols simulated competition (1 round, 2 rounds and 3 rounds). The combats were filmed in order to quantify the actual time spent fighting in each round. The estimate of the aerobic (WAER), anaerobic alactic (WPCR) and anaerobic lactic (W[La-]) energy systems was carried out through the oxygen consumption during the activity, the fast component of excess post-exercise oxygen consumption, and the delta of blood lactate concentration in each round, respectively. The mean data between the high intensity actions and moments of low intensity (step and pause) was ~1:7. The results of WAER, WPCR and W[La-] system contributions were 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectively. Thus, training sessions should be directed mainly to the improvement of the anaerobic alactic system (responsible by the high-intensity actions), and of the aerobic system (responsible by the recovery process between high-intensity)

Objetivos: Avaliar o comportamento da pressão arterial (PA) e da frequência cardíaca (FC) durante a fase de dor da migrânea em pacientes sem hipertensão arterial sistêmica (HAS). Avaliar essas variáveis em função da intensidade de dor e se elas sofrem influência do uso agudo de ibuprofeno. Métodos: Dez pacientes (nove mulheres), entre 21 e 43 anos, com diagnóstico de migrânea foram selecionados. Todos tinham diagnóstico de migrânea sem aura e quatro deles também tinha diagnóstico de migrânea com aura. Eles apresentavam de 3 a 11 dias de dor por mês, não tinham qualquer outro problema de saúde e não estavam em tratamento profilático para migrânea. Além disso, não utilizavam medicamentos que pudessem interferir na PA ou FC. Os pacientes foram submetidos à anamnese e exame físico. Para descartar HAS, foram submetidos a medições convencionais da PA e Medidas Ambulatoriais da Pressão Arterial por 24h. A aquisição das medidas de PA e FC nos períodos livres de dor (interictal) foram realizadas por meio de Medidas Residenciais da Pressão Arterial (MRPA) por quatro a cinco dias consecutivos, com a obtenção de seis medidas ao dia. Para a aquisição das medidas de PA e FC no período de dor da migrânea (ictal), os pacientes foram orientados a fazer MRPA a cada 10 minutos nas duas primeiras horas de dor e, após, a cada 15 minutos até o final da crise. Ainda, deveriam assinalar em um tipo de diário de cefaleia as características da dor a cada hora. Permitiu-se o uso de 400mg de ibuprofeno como tratamento de resgate após o final da segunda hora de dor. Para análise estatística, comparamos os valores de pressão arterial sistólica (PAS), pressão arterial diastólica (PAD), pressão arterial média (PAM) e FC realizadas no período interictal com as realizadas no período ictal. As variáveis obtidas durante a cefaleia foram comparadas em função da intensidade de dor e em função do uso de ibuprofeno. Resultados: As médias de PAS, PAD, PAM do período ictal foram significativamente menores que as do período interictal (p0,01). Comparando as médias dos valores de PAS, PAD, PAM e FC do período interictal com as do período ictal divididas por hora para as primeiras quatro horas de dor, observamos que houve uma redução progressiva dos valores de PAS, PAD e PAM durante todo esse período (p0,01). Quanto à FC, observamos que houve aumento de seus valores na primeira hora de dor (p0,02). Houve uma tendência de redução dos valores das médias de PAS, PAD e PAM nas dores de moderada e forte intensidade. Com relação ao ibuprofeno, não notamos diferenças nas variáveis. Conclusões: Durante a fase de dor da migrânea ocorre uma redução da PA desde a primeira hora de dor. Por outro lado, há um aumento dos valores da FC apenas na primeira hora de dor. Houve uma tendência de que os valores de PA reduzissem à medida que a dor progredisse de leve para moderada e forte intensidades. O uso de 400mg de ibuprofeno não promoveu alterações nas variáveis analisadas. / Objectives: To analyse the behavior of blood pressure (BP) and heart rate (HR) during migraine headache in patients without hypertension (HBP). To assess the values of BP and HR according to the intensity of pain, and to check if those variable are influenced by 400 mg of ibuprofen. Methods: Ten patients (nine women), 21 to 43 years-old, with migraine diagnosis were select. All of them had migraine without aura and four of them also had migraine with aura. They had from 3 to 11 days of headache a month, no other healthy problem, and werent on migraine prophylactic treatment. Also, they werent using other drugs that could interfere on BP and HR. Patients were submitted to anamnesis and physical examination. Hypertension was ruled out through office and ambulatory BP measurements for 24 hours. To obtain the values of pain-free period, BP and HR were measured through home measurements which were done from 4 to 5 consecutives days, 6 times a day. To obtain the values of migraine headache period, patients were asked to measure their BP and HR from the beginning to the end of the attack. During the first two hour of pain, they should do the measures each 10 minutes, and after that each 15 minutes until the end of the attack. During the last procedure, patients should write in a kind of headache diary their headache characteristics each hour. Using of 400 mg of ibuprofen was just allowed at the end of the second hour of pain. To statistical analysis, the values of systolic (SBP), diastolic DBP), mean (MBP) blood pressure and HR from pain-free period were compared with the values of these variables from headache period. The values of these variables from headache period were also compared according the intensity of pain and the intake of ibuprofen. Results: The mean values of SBP, DBP and MBP from headache period were statistically lower than those from pain-free period (p0,01). Comparing mean values of SBP, DBP, MBP and HR from pain-free period to means from the headache period, separated by hour, for the first 4 hours of pain, we verified there were a progressive reduction of SBP, DBP, MBP during this phase (p0,01). About the HR, we noticed its values raised during the first hour of pain (p0,02). There was a trend of SBP, DBP and MBP values to be lower during moderate and severe pain. Regarding the use of ibuprofen, we didnt notice differences on BP or HR values. Conclusions: During migraine headache, BP values are lower since the first hour of pain. On the other hand, HR values were different just in the first hour of pain where they were higher. There was a trend of BP lowering as the pain progressed from mild to moderate and severe intensity. Ibuprofen (400 mg) didn\'t change the variables values.

Uma função autonômica adequada é essencial para a manutenção da estabilidade hemodinâmica durante a hemorragia. Diversos estudos tem demonstrado que a análise da variabilidade da frequência cardíaca (VFC) é uma técnica não-invasiva promissora para avaliação da modulação autonômica no trauma, mostrando haver uma associação entre a VFC e desfecho clínico. O objetivo deste estudo foi avaliar a VFC durante o choque hemorrágico e reposição volêmica, comparando a variáveis hemodinâmicas e metabólicas tradicionais. Vinte porcos anestesiados e ventilados mecanicamente foram submetidos ao choque hemorrágico (60% da volemia estimada) e avaliados durante 60 minutos sem reposição volêmica. Os animais sobreviventes foram tratados com solução de Ringer lactato e avaliados por mais 180 minutos. Medidas de VFC (no domínio do tempo e da frequência) e variáveis hemodinâmicas e metabólicas foram comparados entre animais sobreviventes e não sobreviventes. Sete dos 20 animais morreram durante o choque hemorrágico e reposição volêmica inicial. Todos os animais apresentaram diminuição do intervalo RR e aumento das medidas de VFC no domínio do tempo durante a hemorragia, sendo restaurados os valores basais após reposição volêmica. Embora não significante estatisticamente, foram observados diminuição de LF e LF/HF durante os estágios iniciais de sangramento, recuperação dos valores basais durante a manutenção do choque hemorrágico e aumento após reposição volêmica. Os animais não sobreviventes apresentaram valores significativamente menores de pressão arterial média (43 ± 7 vs 57 ± 9) e índice cardíaco (1,7 ± 0,2 vs 2,6 ± 0,5) e valores maiores de lactato (7,2 ± 2,4 vs 3,7 ± 1,4), excesso de base (-6,8 ± 3,3 vs -2,3 ± 2,8) e potássio sérico (5,3 ± 0,6 vs 4,2 ± 0,3), trinta minutos após indução do choque hemorrágico. Concluímos que as medidas de VFC não foram capazes de discriminar sobreviventes e não-sobreviventes durante choque hemorrágico. As variáveis metabólicas e hemodinâmicas foram melhores em refletir a gravidade do choque hemorrágico do que as medidas de VFC / An adequate autonomic function is essential for maintaining the hemodynamic stability during hemorrhage. The analysis of heart rate variability (HRV) has been shown as a promising non-invasive technique for assessing the cardiac autonomic modulation in trauma, and several studies have demonstrated the association between HRV and clinical outcome. The aim of this study was to evaluate HRV during hemorrhagic shock and fluid resuscitation, comparing to traditional hemodynamic and metabolic parameters. Twenty anesthetized and mechanically ventilated pigs were submitted to hemorrhagic shock (60% of estimated blood volume) and evaluated for 60 minutes without fluid replacement. Surviving animals were treated with Ringer solution and evaluated for an additional period of 180 minutes. HRV metrics (time domain and frequency domain) as well as hemodynamic and metabolic parameters were evaluated in survivors and non-survivors animals. Seven of the 20 animals died during hemorrhage and initial fluid resuscitation. All animals presented an increase in time-domain HRV measures during haemorrhage and fluid resuscitation restored baseline values. Although not significantly, normalized low-frequency and LF/HF ratio decreased during early stages of haemorrhage, recovering baseline values later during hemorrhagic shock and increased after fluid resuscitation. Non-surviving animals presented significantly lower mean arterial pressure (43 ± 7 vs 57 ± 9) and cardiac index (1.7 ± 0.2 vs 2.6 ± 0.5) and higher levels of plasma lactate (7.2 ± 2.4 vs 3.7 ± 1.4), base excess (-6.8 ± 3.3 vs -2.3±2.8) and potassium (5.3 ± 0.6 vs 4.2 ± 0.3), 30 minutes after hemorrhagic shock compared to surviving animals. Conclusions: The HRV metrics were not able to discriminate survivors from non-survivors during hemorrhagic shock. Moreover, metabolic and hemodynamic variables were more reliable to reflect hemorrhagic shock severity than HRV metrics

<p>Heart rate variability (<b>HRV</b>), or the variation in time between adjacent heart beats over time, is a non-invasive proxy measure of autonomic nervous system (<b>ANS</b>) function that has been used regularly in studies focused on evaluating livestock stress and welfare. The autonomic nervous system regulates involuntary physiological processes (<i>e.g.</i> respiration and heart rate) and consists of two main components, the parasympathetic (<b>PNS</b>), and sympathetic (<b>SNS</b>) branches, which act to maintain bodily homeostasis (PNS) or stimulate the “fight-or-flight” response after exposure to a stressor (SNS). Traditional linear HRV measures provide an estimation of overall autonomic activity or changes to the balance between the PNS and SNS branches by evaluating changes to the mean, variance, or frequency spectra of the R-R intervals. </p><p>To interpret HRV data obtained via linear HRV measures, particularly spectral HRV analysis, a linear assumption has to be assumed where SNS and PNS activity act in a purely antagonistic manner. However, this assumption is not always met. In many cases, ANS activity is altered in a nonlinear manner, which is reflected to some degree in the variability of heart rate output. Therefore, HRV measures that evaluate nonlinear changes to organizational or structural aspects of the R-R interval variability may be a useful compliment to traditional linear HRV measures for distinguishing between stressed and non-stressed states. The purpose of this dissertation was to evaluate the use of nonlinear HRV measures for evaluating dairy calf disbudding pain, piglet castration pain, growing pig heat stress, and as potential indicators of the subsequent immune response to a lipopolysaccharide (<b>LPS</b>) challenge in growing pigs.</p><p>Chapter 1 provides a knowledge base for understanding HRV and its use as a measure of autonomic stress in studies with livestock species. A brief explanation of animal welfare science, measures used to evaluate an animal’s welfare, and a demonstration of need for non-invasive physiological measures is provided before discussing the physiological basis of HRV. Relevant linear and nonlinear HRV measures are explained and examples of their use in livestock stress research are provided. Finally, a rationale for the studies conducted in this dissertation is presented.</p><p>Chapter 2 evaluates the use of HRV as an indicator of castration pain in 9-d-old piglets over a 3-d experimental period. Compared to sham castrated piglets, surgically castrated piglets exhibited greater low frequency to high frequency ratios (<b>LF/HF</b>), reduced sample entropy (<b>SampEn</b>), and greater percent determinism (<b>ÞT</b>) during the post-castration period. However, postural behavior was not different between treatments and serum cortisol concentrations only tended to differ between treatments at 1 and 24 h post-castration treatment, with surgically castrated pigs having numerically greater serum cortisol concentrations at both timepoints. These results demonstrate the ability of nonlinear HRV measures (SampEn and ÞT) to complement the physiological interpretation of linear HRV measures (LF/HF) in response to castration. Specifically, pigs who were surgically castrated exhibited more regularity (SampEn) and periodicity (ÞT) in their HRV data, and potentially more sympathetic activity (LF/HF) compared to sham castrated piglets, indicating greater pain-related stress. Additionally, HRV was a more sensitive measure of the stress response to castration than readily identifiable behaviors such as posture and the serum cortisol response.</p><p>Chapter 3 evaluates the use of HRV as an indicator of disbudding pain in dairy heifer calves (4 to 7-wk of age) over a 5-d experimental period. Calves who were given lidocaine and meloxicam prior to disbudding exhibited lower mean R-R interval (<b>RR</b>) values and a greater short-term detrended fluctuation analysis scaling exponent (<b>DFAα₁</b>) than sham disbudded calves. Together, these results indicate that calves who received pain mitigation exhibited greater pain-related stress (RR) and reduced physiological complexity in their heart rate signal (DFAα₁). Calves who were disbudded without pain mitigation had an intermediate response compared to sham disbudded calves and calves provided lidocaine and meloxicam. However, their numerical values closely followed those of calves provided lidocaine and meloxicam. These results demonstrate the usefulness of nonlinear HRV measures (DFAα₁) for evaluating nonlinear and correlational aspects of physiological complexity in response to disbudding. Additionally, the HRV results suggest that the provision of meloxicam does not reduce the amount of pain-related stress experienced by calves following disbudding.</p><p>Chapter 4 evaluates the use of HRV as an indicator of heat stress in growing pigs exposed to an acute heat episode. Heat stressed pigs exhibited greater body temperatures and spent less time in an active position compared to thermoneutral control pigs. Additionally, heat stressed pigs displayed an altered nonlinear HRV response to the acute heat phase compared to non-heat stressed control pigs. Specifically, heat stressed pigs exhibited lower SampEn and tended to exhibit greater ÞT, but no alterations to linear measures were observed in response to the acute heat episode. The low frequency to high frequency ratio was higher in heat stressed pigs during the period following the acute heat phase. Therefore, nonlinear HRV measures (particularly SampEn) may be more sensitive to the immediate physiological stress response to increased environmental temperature than traditional linear HRV measures.</p><p>Chapter 5 evaluates the use of baseline HRV as a potential indicator of the subsequent cortisol and pro-inflammatory cytokine response to an LPS challenge in growing pigs. The time for a pig to approach a human (<b>approach time)</b> prior to LPS administration was inversely related to baseline standard deviation of the R-R intervals (<b>SDNN</b>), and directly related to RR and the mean length of diagonal lines in a recurrence plot (<b>Lmean</b>). This result may have implications for the use of HRV as a measure of temperament in livestock species, since pigs with lower baseline SDNN (<i>i.e.</i> greater stress) and greater baseline Lmean (<i>i.e.</i> increased periodicity length in HRV data; greater stress) values took longer to approach a human observer before LPS administration (which occurred 1 d after HRV measurement). Area under the curve values for approach time following LPS administration were inversely related to high frequency spectral power (<b>HF</b>) and directly related to body weight, where pigs with low baseline HF values (<i>i.e. </i>lower parasympathetic activity) and higher body weights were slower to approach a human observer following LPS administration. Additionally, pigs with greater Lmean values had a greater change in body temperature following LPS administration. In conclusion, while baseline HRV measures were not directly representative of the cortisol or cytokine response following an LPS challenge, HF and Lmean may be useful indicators for evaluating certain aspects (sickness behavior and fever) of the innate immune response to an LPS challenge. <b></b></p><p> In conclusion, these studies demonstrate the usefulness of nonlinear HRV measures for evaluating livestock stress. Measures such as sample entropy and those derived from recurrence quantification analysis (ÞT, Lmean) seem to be particularly useful for complementing traditional linear HRV measures and, in some cases, are more sensitive measures of the physiological stress response (see chapter 4). Therefore, their inclusion in future studies on livestock HRV is warranted. However, further work is needed to fully elucidate the physiological significance of nonlinear HRV measures and their response to stress.</p>

INTRODUÇÃO: A cineangiocoronariografia é um procedimento médico invasivo que envolve sentimentos de medo e ansiedade. Estudos internacionais têm avaliado o efeito da música como técnica de intervenção para redução da ansiedade utilizando-a antes, durante e depois da cineangiocoronariografia. Contudo, os resultados de sua aplicação durante o procedimento não são consensuais. OBJETIVO: A proposta do presente estudo foi avaliar o efeito da música, aplicada durante a realização do procedimento, na ansiedade de pacientes submetidos à cineangiocoronariografia pela primeira vez. MÉTODOS: Os desfechos estudados foram o nível de ansiedade medido pelo Inventário de Ansiedade Beck, a frequência cardíaca e pressão arterial, ambas medidas pelo método intra-arterial. Participaram do estudo 300 pacientes randomizados entre o grupo controle (procedimento padrão) ou grupo música (cineangiocoronariografia realizada com a intervenção musical). Foi realizado o cegamento da pesquisadora durante toda a coleta e análise estatística dos dados. RESULTADOS: Os grupos eram semelhantes em relação às características de base, bem como dados sobre os hábitos musicais dos pacientes e dados da cineangiocoronariografia. Não foram observadas diferenças entre os grupos controle e música para todos os desfechos estudados: nível de ansiedade (p=0,072), pressão arterial sistólica (p=0,379), pressão arterial diastólica (p=0,152) e frequência cardíaca (p=0,853). Notou-se também que, mesmo antes da realização do procedimento, 80,9% do grupo controle e 76,9% do grupo música já apresentavam o menor nível de ansiedade (mínima). As mulheres mostraram-se mais ansiosas do que os homens (p=0,000 pré-exame e p=0,022 pós-exame). Não houve relação na comparação entre ansiedade e diferentes faixas etárias (p=0,352 pré-exame, p=0,198 pós-exame). CONCLUSÃO: A música aplicada no presente estudo durante a cineangiocoronariografia não se mostrou efetiva na redução dos níveis de ansiedade, pressão arterial e frequência cardíaca dos pacientes submetidos ao procedimento pela primeira vez. Constatou-se também que as mulheres são mais ansiosas do que os homens e que não houve relação entre o nível de ansiedade e faixas etárias / BACKGROUND: Coronary angiography is an invasive medical procedure that involves feelings of fear and anxiety. International studies have evaluated the effects of music intervention to reduce anxiety by using it before, during and after coronary angiography. However, the results of this strategy are not clear. OBJECTIVE: The aim of this study was to evaluate the effect of music, employed during the procedure, on anxiety of patients undergoing coronary angiography for the first time. METHODS: Outcomes were anxiety level measured by the Beck Anxiety Inventory, heart rate and blood pressure, both measured by intra-arterial method. The study included 300 patients randomized between the control group (standard procedure) or music group (standard procedure with a music intervention). The researcher was blinded throughout the data collection and statistical analysis. RESULTS: Baseline variables were adequatly balanced between both groups, as well as data on musical habits and coronary angiography. No differences were observed between the control group and music group in any of the outcomes: level of anxiety (p = 0.072), systolic blood pressure (p = 0.379), diastolic blood pressure (p = 0.152) and heart rate (p = 0.853). It was also noted that even before the procedure, 80.9% of the control group and 76.9% of the music group had low level of anxiety. Women were more anxious than men (p = 0.000 pre-test and p = 0.022 post-test). No relationship was found between anxiety and age (p = 0.352 pre-test, p = 0.198 post-test). CONCLUSION: The music used in this study during coronary angiography was not effective in reducing anxiety levels, blood pressure or heart rate in patients undergoing the procedure for the first time. It was also found that women are more anxious than men and that there was no relationship between anxiety levels and age

Slow and deep breathing (SDB) has long been regarded as a nonpharmacological method for dealing with several physiological and emotional imbalances, and widely used for relaxation purposes. There is, however, limited understanding of the putative mechanisms by which SDB acutely impacts the cardiovascular and autonomic systems to elicit chronic adaptations. The present thesis explored how the manipulation of breathing pattern and intrathoracic pressure during SDB could further the understanding of the regulatory mechanisms that underpin the acute cardiovascular response to SDB. This thesis makes an original contribution to the existing knowledge by reporting a previously undescribed inversion of normal within-breath (inspiration vs. expiration) left ventricular stroke volume (LVSV) pattern for breathing frequencies < 8 breaths∙min-1. This finding might reflect the influence of a lag between enhanced right atrial filling and right ventricular stroke volume during inspiration, and its expression in left ventricular stroke volume; this lag results from the time required for blood to transit the pulmonary circulation. Furthermore, blood pressure variability (BPV) was reduced significantly at the lowest breathing frequencies, likely due to the involvement of baroreflex mediated responses. The pattern of responses was consistent with the buffering of respiratory-driven fluctuations in left ventricular cardiac output (Q̇) and arterial blood pressure (ABP) by within breath fluctuations in heart rate (fc), i.e., respiratory sinus arrhythmia (RSA) (Chapter 4). Chapter 5 demonstrated that magnifying negative intrathoracic pressure with inspiratory loading during SDB increased inspiratory pressure-driven fluctuations in LVSV and fc, and enhanced Q̇, independently of changes in VT and fR. The data support an important contribution to the amplification of RSA, during SDB, of previously underappreciated reflex, and/or 'myogenic', cardiac response mechanisms. The findings in Chapter 6 confirmed that inspiratory loading during SDB amplified the effects observed with un-loaded SDB (reported in chapter 5). In contrast, expiratory loading increased ABP and attenuated RSA, LVSV and Q̇ during SDB. A lower RSA for higher ABP, supports the presence of a formerly underappreciated contribution of sinoatrial node stretch to RSA, and throws into question the clinical benefits of expiratory resisted SDB, particularly in hypertensive populations. In conclusion, the findings of the present thesis provide novel information regarding the mechanisms contributing to acute cardiovascular response to SDB. These new insights may contribute to the development of more effective SDB interventions, geared towards maximising the perturbation to the cardiovascular control systems.

A obesidade é considerada atualmente um dos maiores problemas de saúde em humanos, sendo considerada endêmica entre adultos e crianças. Situação semelhante tem sido observada em medicina veterinária, como conseqüência de um desequilibrio energético que muitas vezes é resultado do tipo de manejo que os animais recebem. É caracterizada pelo acúmulo excessivo de gordura, superando 15% do peso ideal e culmina com várias modificações nas funções orgânicas. Em humanos, sabe-se que o excesso de peso gera alterações na hemodinâmica, no metabolismo, no estado inflamatório, gerando um aumento do volume circulatório, ativação do sistema nervoso simpático e hipertrofia ventricular e levando ao remodelamento cardíaco. As arritmias cardíacas têm sido descritas em indivíduos obesos, geralmente acompanhadas da hipertrofia ventricular esquerda ou da síndrome da apnéia do sono. A disfunção autonômica, avaliada pela redução da variabilidade da freqüência cardíaca, também é observada nos humanos obesos. Não foram encontradas arritmias em estudo com cães obesos no ECG de rotina. O Holter permite um registro contínuo da atividade elétrica cardíaca, enquanto o paciente continua com as suas atividades diárias normais, assim uma das suas principais indicações é a identificação de presença de arritmias que não são detectados pelo eletrocardiograma de curta duração. Desta forma, o objetivo do estudo foi avaliar, pelo método Holter, a presença de arritmias e, pela análise da variabilidade da freqüência cardíaca, avaliar o balanço autonômico em cães obesos. Para isto, foram selecionados 67 cães obesos com escore de condição corporal (ECC) 8 e 9 e 65 cães com peso ideal (ECC=5), pareados por raça/porte, gênero e idade. Os cães obesos não apresentaram alteração no eletrocardiograma de rotina e nem na mensuração da pressão arterial em relação ao grupo controle. No entanto, o grupo obeso, apresentou maior número de extrassístoles ventriculares, discreta hipertrofia de ventrículo esquerdo. Também foram observados menores valores nos parâmetros de variabilidade da freqüência cardíaca, indicando assim, uma disfunção autonômica. / Obesity is currently one of the major health problems in humans, and it is considered endemic among adults and children. A similar situation has been found in veterinary medicine, as a consequence of energy imbalance, resulting, most of the times from the management of these animals. It is characterized by excessive accumulation of fat, over 15% of ideal body weight, and culminates with various organic function modifications. In humans, it is known that body weight excess generates changes on hemodynamics, metabolism, inflammatory status, leading to increased circulatory volume, sympathetic nervous system activation, ventricular hypertrophy and leads to cardiac remodeling. Arrhythmias have been described in obese people, generally accompanied by ventricular hypertrophy or sleep apnea. The autonomic dysfunction, assessed by a decrease in heart rate variability, is also observed in humans. Arrhythmias were not observed in a previous study of routine ECG in obese dogs. Holter monitoring allows for the continuous registration of the electrical activity of the heart, while the patient continues the normal daily activities. Therefore, one of the main indications is the identification of the presence of arrhythmias that are not detected by the short duration ECG. The purpose of this study was to assess, by Holter method, the presence of cardiac arrhythmias, and by heart rate variability, to evaluate the autonomic balance in obese dogs. Sixty seven dogs, with a body condition score (BCS) of 8 and 9, and 65 dogs with ideal body (BCS= 5) weight were selected, matched for breed/size, gender and age. The obese dogs did not present changes on the routine ECG and blood pressure measurement, in relation to control group. Despite that, the obese group showed greater number of ventricular extra-systoles and mild left ventricular hypertrophy. There were also lower values of heart rate variability parameters, which indicate an autonomic dysfunction.