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The time course for recovery after anesthesia is poorly described for tricaine methanesulfonate (MS-222). We suggest that the baroreflex and the heart rate variability (HRV) could be used to index the recovery of the autonomic modulation after anesthesia. We analyzed the recovery profile of behavioral and physiological parameters over time to analyze the progression of recovery after anesthesia of American bullfrogs with MS-222. Mean heart rate stabilized after 17 h, whereas the baroreflex efficiency index took 23 h and the baroreflex operating gain, 29 h. Mean arterial pressure recovered after 26 h. Power spectral density peaked at 23 h and again after 40 h. Baroreflex was a relevant component of the first phase of HRV, while autonomic modulation for resting may take longer than 40 h. We suggest that physiological recovery is a complex phenomenon with multiple progressive phases, and the baroreflex may be a useful tool to observe the first substantial recovery of post-instrumentation capacity for autonomic modulation.
Assuntos
Aminobenzoatos , Sistema Nervoso Autônomo , Barorreflexo , Frequência Cardíaca , Rana catesbeiana , Animais , Barorreflexo/fisiologia , Frequência Cardíaca/fisiologia , Sistema Nervoso Autônomo/fisiologia , Rana catesbeiana/fisiologia , Aminobenzoatos/farmacologia , Anestesia , Masculino , Pressão Sanguínea/fisiologia , Anestésicos/farmacologiaRESUMO
OBJECTIVE: We investigated the systemic arterial hypertension effects on cardiovascular autonomic modulation and baroreflex sensitivity (BRS) in women with or without preserved ovarian function. METHODS: A total of 120 women were allocated into two groups: middle-aged premenopausal women (42 ± 3 y old; n = 60) and postmenopausal women (57 ± 4 y old; n = 60). Each group was also divided into two smaller groups (n = 30): normotensive and hypertensive. We evaluated hemodynamic and anthropometric parameters, cardiorespiratory fitness, BRS, heart rate variability (HRV), and blood pressure variability. The effects of hypertension and menopause were assessed using a two-way analysis of variance. Post hoc comparisons were performed using the Student-Newman-Keuls test. RESULTS: Comparing premenopausal groups, women with systemic arterial hypertension showed lower BRS (9.1 ± 4.4 vs 13.4 ± 4.2 ms/mm Hg, P < 0.001 ) and HRV total variance (1,451 ± 955 vs 2,483 ± 1,959 ms 2 , P = 0.005) values than normotensive; however, the vagal predominance still remained. On the other hand, both postmenopausal groups showed an expressive reduction in BRS (8.3 ± 4.2 vs 11.3 ± 4.8 ms/mm Hg, P < 0.001) and HRV characterized by sympathetic modulation predominance (low-frequency oscillations; 56% ± 17 vs 44% ± 17, P < 0.001), in addition to a significant increase in blood pressure variability variance (28.4 ± 14.9 vs 22.4 ± 12.5 mm Hg 2 , P = 0.015) compared with premenopausal groups. Comparing both postmenopausal groups, the hypertensive group had significantly lower values ââof HRV total variance (635 ± 449 vs 2,053 ± 1,720 ms 2 , P < 0.001) and BRS (5.3 ± 2.8 vs 11.3 ± 3.2 ms/mm Hg) than the normotensive. CONCLUSIONS: Hypertensive middle-aged premenopausal women present HRV autonomic modulation impairment, but they still maintain a vagal predominance. After menopause, even normotensive women show sympathetic autonomic predominance, which may also be associated with aging. Furthermore, postmenopausal women with hypertension present even worse cardiac autonomic modulation.
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Sistema Nervoso Autônomo , Barorreflexo , Pressão Sanguínea , Frequência Cardíaca , Hipertensão , Menopausa , Pós-Menopausa , Pré-Menopausa , Humanos , Feminino , Pessoa de Meia-Idade , Hipertensão/fisiopatologia , Adulto , Barorreflexo/fisiologia , Frequência Cardíaca/fisiologia , Sistema Nervoso Autônomo/fisiopatologia , Sistema Nervoso Autônomo/fisiologia , Pressão Sanguínea/fisiologia , Menopausa/fisiologia , Pós-Menopausa/fisiologia , Pré-Menopausa/fisiologia , Sistema Cardiovascular/fisiopatologia , Aptidão Cardiorrespiratória/fisiologiaRESUMO
BACKGROUND: There are important physiological changes in the heart rate autonomic modulation in pregnant women and these changes may affect the way their bodies respond to exercise stimulus. The objective of this review is to verify the physical exercise influence on autonomic modulation of heart rate in pregnant women. METHODS: This study is a Systematic Review. The electronic databases used to search for the studies were Cochrane Library, MEDLINE via PUBMED, Regional Health Portal and EMBASE. Experimental studies that evaluated heart-rate variability in pregnant women practicing physical exercises were included. And articles that addressed only fetal heart-rate variability, case reports, congress abstracts, clinical trial protocols without results, preprints, and gray literature were excluded. There were no language or publication year restrictions. The descriptors used in the Search were Cardiac Chronotropism, Sympathetic Nervous System, Pregnancy, and Physical Exercise. For statistical analysis, the fixed effect model was used. RESULTS: A total of 3106 articles were found, and 12 studies were included, which 5 were nonrandomized clinical trials, 4 were randomized clinical trials, and 3 were cross-sectional studies. Three hundred and four pregnant women were included in the studies. The application of physical exercise was varied, but in general they used aerobic exercises and with increased variability of the heart rate and reflex on the autonomic modulation of heart rate. CONCLUSION: Most studies demonstrate benefits heart rate in pregnant women, but limited research makes it hard to compare specific types of exercise and larger studies are needed to identify the best exercise.
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Sistema Nervoso Autônomo , Exercício Físico , Frequência Cardíaca , Feminino , Humanos , Gravidez , Sistema Nervoso Autônomo/fisiologia , Exercício Físico/fisiologia , Frequência Cardíaca/fisiologiaRESUMO
INTRODUCTION: The wrapping of the newborn in an orthopedic tubular mesh, simulating a cocoon, can allow the infant to regain the feeling of security and stability experienced in the uterus given that the movement of one of the parts of the body exerts tactile and pressure variation in others. OBJECTIVE: We aimed to evaluate the influence of an orthopedic tubular mesh, simulating a cocoon, in therapeutic positioning, on the variables of the autonomous, motor, and regulatory systems of preterm newborns. METHODS: A controlled and randomized clinical trial was conducted with preterm newborns positioned in dorsal decubitus and divided into two groups: (a) cocoon - newborns covered with an orthopedic tubular mesh, and (b) control - newborns positioned according to the sector's routine and without the use of an orthopedic mesh. During the follow-up, each newborn was placed in the position for 30 min and was recorded for a total of 2 min, once at the beginning and again at the end of the observation period. Variables related to the autonomous system (heart rate, respiratory rate, and peripheral oxygen saturation), motor system (general movements), and regulatory system (Neonatal Infant Pain Scale) were evaluated before and after the intervention. The videos were evaluated by a researcher blind to the purpose of the study, and the resulting data were analyzed using SPSS. RESULTS: Of the 40 preterm newborns evaluated (32.5 ± 1.83 weeks), 21 were female, and 20 were allocated to the cocoon group. The variables related to the autonomous, motor, and regulatory systems remained unchanged following the positioning in the cocoon, as compared to the typical positioning employed in the neonatal unit. CONCLUSION: The simulation of a cocoon, utilizing an orthopedic tubular mesh, when applied to preterm newborns admitted to a neonatal intensive care unit can contribute to maintaining low levels of stress, without altering variables of the autonomous, motor, and regulatory systems.
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Recém-Nascido Prematuro , Humanos , Recém-Nascido , Recém-Nascido Prematuro/fisiologia , Feminino , Masculino , Frequência Cardíaca/fisiologia , Sistema Nervoso Autônomo/fisiologia , Sistema Nervoso Autônomo/fisiopatologia , Posicionamento do Paciente/métodos , Taxa Respiratória/fisiologia , Medição da DorRESUMO
The negative impact of loneliness on the health of the elderly is particularly noticeable because of the effects of central control on the autonomic nervous system. Such an impact can be assessed through heart rate variability (HRV) analysis and can be modified using HRV biofeedback training. This study aimed to investigate the impact of different levels of social interaction reported by the elderly on HRV before and after training with HRV biofeedback and after a follow-up period. The participants of this pilot study comprised 16 elderly people of both sexes with a mean age of 71.20 ± 4.92 years. The participants were divided into two groups, the loneliness group (N = 8) and the no-loneliness group (N = 8), based on a combination of both criteria: the institutionalization condition (institutionalized or not) and the score on the loneliness scale (high or low). All participants had their HRV components recorded at baseline, after 14 training sessions with HRV biofeedback (three times a week, 15 min each for 4.5 weeks), and after 4.5 weeks of follow-up without training. After HRV biofeedback training, HRV components increased in both groups. However, the gains lasted at follow-up only in the no-loneliness group. In conclusion, loneliness can influence the maintenance of HRV after interruption of training with HRV biofeedback in the elderly. HRV biofeedback training can be an innovative and effective tool for complementary treatment of elderly individuals, but its effects on lonely elderly individuals need to be further investigated.
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Biorretroalimentação Psicológica , Frequência Cardíaca , Solidão , Humanos , Masculino , Feminino , Projetos Piloto , Frequência Cardíaca/fisiologia , Idoso , Biorretroalimentação Psicológica/fisiologia , Solidão/psicologia , Sistema Nervoso Autônomo/fisiologia , Interação SocialRESUMO
The autonomic nervous system (ANS) coordinates multiple reflex actions which are essential for life. The tests employed to evaluate the ANS provide valuable information of the functional state of these reflex arcs. The ideal test should be simple to perform, noninvasive, reproducible, sensitive, specific, safe, and appropriate for longitudinal studies. The availability of computer-based techniques has facilitated the electrophysiological assessment of ANS-mediated reflexes. The information provided by autonomic testing must be analyzed in combination with the clinical history and physical examination of the patient, allowing for a hypothesis that can be tested. Properly performed and interpreted, ANS testing can be used to confirm the presence of an ANS disturbance and the involved functional pathways, as well as the extent, intensity, and site of injury. This chapter describes the most important electrophysiological tests used to evaluate the ANS control of cardiovascular reflexes and sweat gland activity.
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Doenças do Sistema Nervoso Autônomo , Humanos , Doenças do Sistema Nervoso Autônomo/diagnóstico , Doenças do Sistema Nervoso Autônomo/etiologia , Sistema Nervoso Autônomo/fisiologia , ReflexoRESUMO
BACKGROUND: There is little evidence that nutraceuticals from beetroot extract are beneficial with regards to recovery of the cardiovascular parameters and the autonomic nervous system (ANS) after submaximal aerobic exercise, though this formulation is employed widely for this purpose. OBJECTIVE: To study the effects of beetroot extract supplementation on the recovery of cardiorespiratory and autonomic parameters after a session of submaximal aerobic exercise. METHODS: Sixteen healthy male adults commenced a cross-over, randomized, double-blind and placebo-controlled trial. Beetroot extract (600 mg) or placebo (600 mg) were ingested 120 min prior to evaluation on randomized days. We assessed systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), mean arterial pressure (MAP), heart rate (HR) and HR variability (HRV) indexes at Rest and during 60 min of recovery from submaximal aerobic exercise. RESULTS: Beetroot extract ingestion slightly accelerated HR, SBP, DBP and MAP reduction following exercise associated to the placebo protocol (vs. rest). Yet no group effect (p = 0.99) was identified between the beetroot and placebo protocols on HR mean, in addition to interaction (group vs. time) (p = 0.60). No group effect was attained between the SBP (p = 0.90), DBP (p = 0.88), MAP (p = 0.73) and PP (p = 0.99) protocols and no significant differences (group vs. time) were observed between the values of SBP (p = 0.75), DBP (p = 0.79), MAP (p = 0.93) and PP (p = 0.63) between placebo and beetroot protocols. Similarly, the reoccurrence of cardiac vagal modulation after exercise via the HF (ms2) was enhanced, but not with regards to the RMSSD index. No group effect (p = 0.99) was identified for the HF (p = 0.90) and RMSSD (p = 0.67) indices. Likewise, we observed no significant differences (group vs. time) amongst the values of HF (p = 0.69) and RMSSD (p = 0.95) between the placebo and beetroot protocols. CONCLUSION: Whilst beetroot extract might assist the recovery of the cardiovascular and autonomic systems following submaximal aerobic exercise in healthy males, these results seem insignificant owing to minor differences between interventions and are weak clinically.
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Sistema Cardiovascular , Coração , Pressão Sanguínea/fisiologia , Exercício Físico/fisiologia , Suplementos Nutricionais , Sistema Nervoso Autônomo/fisiologia , Frequência Cardíaca/fisiologia , VerdurasRESUMO
BACKGROUND: Currently, and to the best of our knowledge, there is no standardized protocol to measure the effect of low- to moderate-intensity physical exercise on autonomic modulation focused in older people. AIM: Validate a test-retest short-term exercise protocol for measuring the autonomic response through HRV in older people. METHODS: A test-retest study design was used. The participants were selected through intentional non-probabilistic sampling. A total of 105 older people (male: 21.9%; female: 78.1%) were recruited from a local community. The assessment protocol evaluated HRV before and immediately after the 2-min step test. It was performed twice on the same day, considering a time of three chronological hours between the two measurements. RESULTS: The posterior distribution of estimated responses in the Bayesian framework suggests moderate to strong evidence favoring a null effect between measurements. In addition, there was moderate to robust agreement between heart rate variability (HRV) indices and assessments, except for low frequency and very low frequency, which showed weak agreement. CONCLUSIONS: Our results provide moderate to strong evidence for using HRV to measure cardiac autonomic response to moderate exercise, suggesting that it is sufficiently reliable to show similar results to those shown in this test-retest protocol.
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Sistema Nervoso Autônomo , Exercício Físico , Humanos , Masculino , Feminino , Idoso , Frequência Cardíaca/fisiologia , Reprodutibilidade dos Testes , Teorema de Bayes , Exercício Físico/fisiologia , Sistema Nervoso Autônomo/fisiologiaRESUMO
BACKGROUND: Patients with coronavirus disease 2019 on automatic mechanical ventilation have greater heart rate modulation with greater parasympathetic modulation. OBJECTIVE: To analyze the autonomic modulation of heart rate in critically ill patients with coronavirus disease 2019 on invasive mechanical ventilation. METHODS: A cross-section study was carried out with 36 individuals divided into two groups. The control group included patients of both genders, in orotracheal intubation with invasive mechanical ventilation under controlled assisted mode, hospitalized in the intensive care unit for another 24 h. In the non-COVID group, patients diagnosed with coronavirus disease 2019 in the same condition mentioned in the control group. RESULTS: There was a significant increase in heart rate variability (standard deviation of all normal RR intervals recorded at an interval of time; p=0.001; triangular interpolation histogram of RR intervals; p=0.048; and SD2; p=0.014) in the coronavirus disease group compared to the non-COVID group. Successively, the parameters that demonstrate parasympathetic modulation are shown to be higher in the group of patients with coronavirus disease 2019 (root mean square of the square of differences between adjacent normal RR intervals in an interval of time; p<0.001; pNN50; p<0.001; SD1; p=0.002; and high frequency; p=0.022). CONCLUSIONS: There was a greater autonomic modulation of heart rate with a greater parasympathetic modulation in patients with coronavirus disease 2019 on mechanical ventilation.