Changes In Autonomic Nervous System Research Articles

Autonomic Nervous System Changes in Term Infants during Early Skin-to-skin Contact (SSC) : Examination of SSC Effectiveness and the Influence of Meconium-stained Amniotic Fluid

Autonomic Nervous System Changes in Term Infants during Early Skin-to-skin Contact (SSC) : Examination of SSC Effectiveness and the Influence of Meconium-stained Amniotic Fluid

The effect of smartphone light on the physiology signal and cognitive function in circadian environment

Many people are constantly exposed to artificial light caused by digital devices such as computer, smartphone, and TV. Prolonged exposure to artificial light disturbs our circadian rhythm, cognitive function and autonomic nervous system (ANS). Therefore, this study aimed to analyze the alterations in physiological signals and cognitive functions following exposure to smartphone light in order to confirm the effects of artificial light on the human body. Normal adults aged from 21 to 28 were engaged in this study. The experiments were conducted in day (10:00~14:00) and night (8:00~12:00) conditions. Experimental subjects were divided into three groups according to smartphone screen brightness; 50%, 100%, and blue light filter (BLF), then used smartphone for 10 min/set (rest time: 5 min) and repeated the task three times. The ANS changes were confirmed using pulse pressure measurement equipment. Short‐term memory (STM), long‐term memory (LTM), and recognition tests were conducted via language memory test (LMT) and visual memory test (VMT). After using smartphone at daytime condition, 50% group shoed significantly increased ANS activity. Also, LTM and recognition were significantly increased in the 50% and BLP group. In night condition, however, BLF group showed increased LTM and recognition. It has been demonstrated by this study that smartphone light may influence ANS, memory, and cognitive functions. Accordingly, blue light filter is recommended when using smartphone to reduce such harmful alterations.Support or Funding InformationFunds: NRF‐2017R1A2A2A01067169, KGM4611821, 2016 Creative Research Program of Inje University, Republic of KoreaThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Bladder Neuromodulation in Acute Spinal Cord Injury via Transcutaneous Tibial Nerve Stimulation: Cystometrogram and Autonomic Nervous System Evidence From a Randomized Control Pilot Trial.

Aim: Percutaneous tibial nerve stimulation is used to decrease incontinence in chronic neurogenic bladder. We report the findings from a subset of patients in a randomized control trial of transcutaneous tibial nerve stimulation (TTNS) for bladder neuromodulation in acute spinal cord injury (SCI) in whom heart rate variability (HRV) was recorded before and after cystometrogram (CMG). The aim was to correlate autonomic nervous system (ANS) changes associated with the CMG changes after the trial using HRV analyses.Methods: The study was a double-blinded sham-controlled 2-week trial with consecutive acute SCI patients admitted for inpatient rehabilitation, randomized to TTNS vs. control sham stimulation. Pre- and Post- trial CMG were performed with concurrent 5-min HRV recordings with empty bladder and during filling. Primary outcomes were changes with CMG between/within groups and associations to the HRV findings.Results: There were 10 subjects in the TTNS group and 6 in the control group. Pre-trial baseline subject characteristics, blood pressures (BPs), and CMG were similar between groups. In both groups, the pre-trial systolic BP increased during filling CMG. After the trial, the control group had significantly increased detrusor pressure and counts of detrusor-sphincter dyssynergia on CMG, not seen in the TTNS group. Also, the control group did not maintain rising BP post-trial, which was observed pre-trial and remained in the TTNS group post-trial. HRV was able to detect a difference in the ANS response to bladder filling between groups. Post-trial HRV was significant for markers of overall increased parasympathetic nervous system activity during filling in the controls, not seen in the TTNS group.Conclusion: Preliminary evidence suggests that TTNS in acute SCI is able to achieve bladder neuromodulation via modulation of ANS functions.Clinical Trial Registration: clinicaltrials.gov, NCT02573402.

Doxorubicin treatments induce significant changes on the cardiac autonomic nervous system in childhood acute lymphoblastic leukemia long-term survivors.

Acute lymphoblastic leukemia (ALL) is one of the leading malignancies in children worldwide. The cardiotoxicity of anti-cancer treatments leads to a dysfunction of the cardiac autonomic nervous system. Protection strategies, with dexrazoxane treatments, were used to counter these adverse effects. The aim of this study was to investigate the effects of the treatments on the cardiac autonomic nervous system. A total of 203 cALL survivors were included in our analyses and were classified into 3 categories based on the prognostic risk group: standard risk, high risk with and without dexrazoxane. A 24-h Holter monitoring was performed to study the cardiac autonomic nervous system. The frequency domain heart rate variability (HRV) was used to validate the cardiac autonomic nervous system modifications. Other analyses were performed using linear HRV indexes in the time domain and non-linear indexes. A frequency domain HRV parameters analysis revealed significant differences on an overall time-period of 24h. A repeated measures ANOVA indicated a group-effect for the low frequency (p = 0.029), high frequency (p = 0.03) and LF/HF ratio (p = 0.029). Significant differences in the time domain and in the non-linear power spectral density HRV parameters were also observed. Anti-cancer treatments induced significant changes in the cardiac autonomic nervous system. The HRV was sensitive enough to detect cardiac autonomic nervous system alterations depending on the cALL risk category. Protection strategies (i.e., dexrazoxane treatments), which were used to counter the adverse effects of doxorubicin, could prevent changes observed in the cardiac autonomic nervous system.

Heart rate variability study in adult Nigerian subjects with sickle cell disease during vaso-occlusive crisis.

Autonomic nervous system (ANS) dysfunction assessed by abnormalities in heart rate variability (HRV) is thought to play a role in the pathophysiology of sickle cell disease (SCD). There is suggestion that changes in ANS may occur in SCD subjects during episodes of vaso-occlusive crises (VOC). The aim of this study was to evaluate the ANS by determining the HRV in patients with SCD during VOC. This was a cross-sectional observational study. HRV studies were carried out in 76 participants with SCD during episodes of VOC. Eighty-two SCD participants in steady state served as controls. Comparison of two independent groups with Student's t-test and Mann-Whitney's test, and multiple linear regressions were also carried out. Participants with SCD and VOC had significant reductions in the time-domain HRV parameters of standard deviation of RR intervals (45.8 [59.36] ms vs. 66.3 [129.2] ms, P = 0.0073) and root mean square of successive differences of RR intervals (48.3 [87.66] ms vs. 74.2 [174.5] ms, P = 0.0015). The frequency-domain HRV indices of low frequency (145.8 [81.62] ms2 vs. 157.5 [68.9] ms2, P = 0.1442) and high frequency (145.0 [118.40] ms2 vs. 146.3 [90.3] ms2, P = 0.3683) were similar between the two groups. Age and the heart rate were the major independent relations of the HRV parameters. Time-domain HRV parameters were impaired during crises in participants with SCD. This finding suggests further impairment of ANS activity in SCD patients during crises. Further studies are needed to clarify the prognostic implication of these findings.

Obstructive sleep apnea syndrome and its relationship with ischaemic stroke

To describe the main physiopathological mechanisms of obstructive sleep apnea syndrome (OSAS) associated with the development of stroke. Sleep breathing disorders have a high prevalence in the healthy population, among them, the OSAS is the most recognized. This syndrome has been associated with vascular diseases such as stroke, hypertension, atrial fibrillation, among others. Stroke has a high global prevalence and is considered a catastrophic disease. The physiopathological mechanisms are of great importance to understand the relationship that exists between OSAS and stroke. Both diseases are associated with molecular, cellular, and autonomic nervous system changes, with systemic cardiovascular repercussions and in particular with the vascular health of the brain. The relationship between OSAS and ischaemic stroke is evident. The advance in the identification of molecular markers and low-cost studies for the identification of OSAS will allow implementing strategies to reduce their consequences in cardiovascular diseases, mainly in ischaemic stroke.

Evaluation of heart rate dynamics during meditation using Poincaré phase plane symbolic measures

Meditation has long been known to affect human physiology which is mediated through autonomic nervous system. The main objective of this study was to assess dynamic changes in cardiac inter-beat intervals and autonomic nervous system during meditation hypothesising that Poincare plots in conjunction with symbolic dynamics can lead to better understanding of the dynamics of the underlying physiological mechanisms. The Poincare phase plane standard descriptors can measure only linear gross variability of the heart rate time series. Moreover, these descriptors exhibit limitations where the occurrence of nonlinear behaviour may be responsible to distinguish the phase plane patterns. We captured the changes in Poincare phase plane patterns resulting from nonlinear processes, during two meditation techniques, employing two complexity measures, symbolic dynamics entropy and forbidden words, which are appropriate to distinguish between the two states. Findings show that symbolic dynamics entropy, also a marker of parasympathetic activity, reveals that during premeditation state, there is parasympathetic dominance while during meditation state there is sympathetic dominance in both the meditation techniques. We also show the presence of nonlinear deterministic structures in the meditation inter-beat interval time series and appropriateness of the application of our nonlinear approach through surrogate data analysis.

On the relevance of symbolizing heart rate variability by means of a percentile-based coarse graining approach

Objective: Symbolic transformations of the cardiac interbeat interval series yield a coarse-grained description of the dynamical information of the underlying system and complement standard measures of heart rate variability. The most commonly utilized coarse graining procedures are strongly influenced by the presence of a few extreme values wasting precious symbols to code very unlikely values. Approach: Here, we used a transformation procedure that ensured the appearance of each symbol with equal probability using a short alphabet, A4 = {0, 1, 2, 3}, and a long alphabet, A6 = {0, 1, 2, 3, 4, 5}. The procedure was applied to the cardiac interbeat interval series of 17 healthy subjects, obtained during graded head-up tilt tests at tilt table inclinations of 0°, 15°, 30°, 45°, 60°, 75°, 90°. The dynamics of the symbolic series was assessed by the rate of symbolic pattern categories. Symbolic patterns of length three were grouped according to the variations of the symbols in each pattern: no variation (0V%), one variation (1V%), two like variations (2LV%) and two unlike variations (2UV%) of the symbols. Main results: As for the alphabet A4, the linear regression analysis on tilt angle showed that 0V% increased with increasing tilt angle whereas 1V%, 2LV% and 2UV% decreased. As for the alphabet A6, the categories 0V%, and 1V% increased with increasing tilt angle whereas 2LV% and 2UV% decreased. Significance: The symbolic transformation ensuring a uniform distribution of the symbols is capable of reflecting changes in the cardiac autonomic nervous system during graded head-up tilt. This approach is more robust against outliers and data with skewed distributions compared to previously used symbolizations.

수면박탈 후 해양심층수 타라소테라피 적용에 따른 스트레스 호르몬 및 자율신경계의 변화

수면박탈 후 해양심층수 타라소테라피 적용에 따른 스트레스 호르몬 및 자율신경계의 변화

Autonomic nervous system development and its impact on neuropsychiatric outcome.

The central autonomic nervous system (ANS) is essential for maintaining cardiovascular and respiratory homeostasis in the newborn and has a critical role in supporting higher cortical functions. At birth, the central ANS is maturing and is vulnerable to adverse environmental and physiologic influences. Critical connections are formed early in development between the ANS and limbic system to integrate psychological and body responses. The Polyvagal Theory, developed by Stephen Porges, describes how modulation of the autonomic vagal impulse controls social responses and that a broad range of neuropsychiatric disorders may be due to impaired vagal balance, with either deficient vagal tone or excessive vagal reactivity. Under additional circumstances of prematurity, growth restriction, and environmental stress in the fetus and newborn, the immature ANS may undergo dysmaturation. Maternal stress and health as well as the intrauterine environment are also quite important and have been implicated in causing ANS changes in the infant and neuropsychiatric diseases in children. This review will cover the aspects of ANS development and maturation that have been associated with neuropsychiatric disorders in children.

Cardiac function in a chemical toxin (organophosphate) induced model of gulf war Illness: benefit of exercise training

BackgroundGulf War Illness (GWI) is a debilitating disease characterized by a cadre of neural, immunological and autonomic symptoms. We show that exposure to a sub‐lethal dose of Sarin lead to autonomic imbalance, cardiomyopathy and central nervous system changes. Diisopropyl fluorophosphate (DFP), an analogue of Sarin (GB), can be used as surrogate agent to produce neurotoxicity and neuro‐inflammation. There is limited information on the use of DFP to produce model of GWI with emphasis on the study of cardiovascular‐autonomic dysfunctions. Consideration was given to the inclusion of exercise training (ET) as part of the treatment of cardiac dysfunction induced by organophosphate exposure.ObjectiveThe aim was to determine the effect of chronic exercise training to the response to DFP on autonomic and cardiovascular function.MethodsMale C57BL/6J mice were divided into two groups (n=8/group): Sedentary (S) and trained (T) before and after DFP exposure. ET was performed on an electronic wheel at low intensity for 1 h/day, 5 days/wk. GWI model was induced by corticosterone (CORT) administered for 7 days (200 mg/l) followed by DFP (1.5 mg/kg, s.c). Cardiac function and ECG were assessed by transthoracic echocardiography (echo) under isoflurane anesthesia (2 – 2.5% on 0.8 l/min of O2).ResultsThe low dose of DFP produced left ventricular dilation on sedentary group, specifically, LV dilation of end systolic area (ESA) (S: 10.34±0.86 vs S+DFP: 6.69 ±0.41 cm2). The ET ameliorated DFP induced toxicity (T: 7.99 ±0.40 vs T+DFP 7.66±0.96cm2). Cardiac Output (CO) was reduced in sedentary group after DFP (S: 20.61±2.63 vs S+DFP: 14.78±0.85 ml/min), not change was observed in the ET group, revealing the efficacy of exercise protocol (T: 16.99±1.69 vs T+DFP: 17.90±1.42 ml/min). Myocardial performance index (MPI) and E/A ratio were significantly increased in S group after DFP exposure (MPI: S: 0.52±0.03 vs S+DFP: 0.60±0.02; E/A: S: 1.29±0.09 vs S+DFP: 1.64±0.07) changes that were not observed on T group (MPI: T: 0.50±0.04 vs T+DFP: 0.48±0.03; E/A: S: 1.35±0.09 vs S+DFP: 1.56±0.10) suggesting protection against DFP. Finally sympathetic modulation (LF) was increased in S group compared initial values and T group, as well as LF/HF ratio. Vagal modulation was similar between both groups.ConclusionIn conclusion, results demonstrate that DFP exerts a negative impact on cardiac/autonomic function. Our critical finding is that chronic exercise prevented most of the cardiovascular dysfunctions elicited by DFP, documenting the positive effects of exercise. This treatment protocol maybe equally applicable to other animal models or even humans.Support or Funding InformationThis work was funded under U.S. Department of Defense grant W81XWH‐13‐2‐0085This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Assessment of Quadratic Nonlinear Cardiorespiratory Couplings During Tilt-Table Test by Means of Real Wavelet Biphase.

In this paper, a method for assessment of quadratic phase coupling (QPC) between respiration and heart rate variability (HRV) is presented. First, a method for QPC detection is proposed named real wavelet biphase (RWB). Then, a method for QPC quantification is proposed based on the normalized wavelet biamplitude (NWB). A simulation study has been conducted to test the reliability of RWB to identify QPC, even in the presence of constant delays between interacting oscillations, and to discriminate it from quadratic phase uncoupling. Significant QPC was assessed based on surrogate data analysis. Then, quadratic cardiorespiratory couplings were studied during a tilt-table test protocol of 17 young healthy subjects. Simulation study showed that RWB is able to detect even weak QPC with delays in the range of [Formula: see text]s, which are usual in the autonomic nervous system (ANS) control of heart rate. Results from the database revealed a significant reduction ([Formula: see text]) of NWB between respiration and both low and high frequencies of HRV in head-up tilt position compared to early supine. The proposed technique detects and quantifies robustly QPC and is able to track the coupling between respiration and various HRV components during ANS changes. The proposed method can help to assess alternations of nonlinear cardiorespiratory interactions related to ANS dysfunction and physiological regulation of HRV in cardiovascular diseases.

Effects of weight changes in the autonomic nervous system: A systematic review and meta-analysis

Obesity has been linked to autonomic dysfunction, which is thought to be one of the main contributors for hypertension, cardiac remodelling and death. Exercise and diet-based weight loss are the mainstay therapy for obesity, but there is a paucity of data regarding the effect of weight changes in autonomic nervous system (ANS) activity. To describe the impact of weight changes in autonomic nervous system. A systematic literature search of four biomedical databases was performed evaluating effects of weight changes, thorough diet and/or exercise-based interventions, in the following ANS outcomes: heart rate variability, namely low frequency (LF)/high frequency (HF) ratio (LF/HF ratio), normalized units of LF (LFnu) and HF (HFnu), muscle sympathetic nerve activity (MSNA), noradrenaline spillover rate (NA-SR), standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD), baroreflex sensitivity and pupillometry. Quality appraisal was performed using the GRADE methodology and, where fitting, studies with comparable outcomes were pooled for meta-analysis. Twenty-seven studies - 7 controlled clinical trials and 20 observational studies - were included. Weight gain was reported in 4 studies and weight loss in all the other studies. Interventions inducing weight changes included: hypocaloric or hypercaloric diets, exercise (strength, endurance or aerobic training) and hypocaloric diet coupled with exercise programs. Most studies which resulted in weight loss reported decreases in LF/HF ratio, LFnu, MSNA burst frequency and incidence, NA-SR, and an increase of baroreflex sensitivity, HF, HFnu and RMSSD, pointing to a parasympathetic nervous system activation. Meta-analysis regarding weight loss interventions showed a significant pooled effect size (95% CI) with a decreased of MSNA burst frequency-5.09 (-8.42,-1.75), MSNA incidence-6.66 (-12.40,-0.62), however this was not significant for SDNN 14.32 (-4.31, 32.96). Weight gain was associated with an increase in LF/HF, LFnu, MSNA burst frequency and incidence. The weight loss effects were potentiated by the association of hypocaloric diet with exercise. Nevertheless, weight changes effects in these outcomes were based in low or very low quality of evidence. Diet and exercise based weight loss appears to increase parasympathetic and decrease sympathetic activity, the opposing effects being observed with weight gain. These findings are not uniformly reported in the literature, possibly due to differences in study design, methodology, characteristics of the participants and techniques used to estimate autonomic nervous activity.

Evaluation of Autonomic Nervous System, Saliva Cortisol Levels, and Cognitive Function in Major Depressive Disorder Patients.

Major depressive disorder (MDD) is associated with changes in autonomic nervous system (ANS) and cognitive impairment. Heart rate variability (HRV) and Pulse pressure (PP) parameters reflect influences of the sympathetic and parasympathetic nervous system. Cortisol exerts its greatest effect on the hippocampus, a brain area closely related to cognitive function. This study aims to examine the effect of HRV, PPG, salivary cortisol levels, and cognitive function in MDD patients by using noninvasive techniques. We have recruited MDD patients, diagnosed based on DSM-V-TR criteria compared with healthy control subjects. Their HRV and PP were measured by electrocardiogram (ECG) and photoplethysmography (PPG). Salivary cortisol levels were collected and measured on the same day. MDD patients exhibited elevated values of mean HR, standard deviation of HR (SDHR), low frequency (LF) power, low frequency/high frequency (LF/HF) ratio, mean PP, standard deviation of pulse pressure (SDPP), and salivary cortisol levels. Simultaneously, they displayed lower values of mean of R-R intervals (mean NN), standard deviation of R-R intervals (SDNN), high frequency (HF) power, and WCST scores. Results have shown that the ANS of MDD patients were dominated by the sympathetic activity and that they have cognitive deficits especially in the domain of executive functioning.

Autonomic Nervous System Changes Associated with Respiratory Cycle and Posture

Autonomic Nervous System Changes Associated with Respiratory Cycle and Posture

Heart rate variability recovery after a skyrunning marathon and correlates of performance

Background: It is well known that vigorous physical activity induces functional changes in cardiac autonomic nervous system (ANS) activity that is sustained several hours after exercise. However, data related to ANS recovery after more extreme endurance events, such as skyrunning marathons, are still lacking. Objective: The aims of this prospective cohort study were firstly, to determine the ANS response to a SkyMarathon, and secondly, to examine correlates of run performance. Methods: Ten male skyrunners aged 37.2 ± 9.2 years were recruited. The race was performed at a mean intensity 85.4 ± 3.7% of heart rate reserve, and lasted for 338 ± 38 min. Morning supine heart rate variability was measured at 10, 2 and 1 days before race, on the race day, at 5 min intervals for 30 min immediately post-race and then at 5 h and 30 h post. High-frequency power (HF, 0.15-0.50 Hz), low-frequency power (LF, 0.05-0.15 Hz), and square root of the mean of the squares of the successive differences (RMSSD) were calculated and transformed by natural logarithm (Ln). Results: Sympathovagal balance (Ln LF/HF) was most likely increased above baseline during the 30 min post-race and returned to baseline by 5 h. Vagal activity (Ln RMSSD and Ln HF) was most likely decreased below baseline during the 30 min post-race and 5 h of post-race, and recovered to baseline by 30 h. Race time correlated with resting heart rate (r = .81), body mass index (r = .73), maximal power output (r = -.70), and maximal oxygen uptake (r = -.61). Conclusions: The SkyMarathon elicited disturbances in ANS activity, with relative sympathetic activity increased up to 5 h post-race and vagal activity recovering by 30 h. Resting heart rate, body mass index, maximal power output, and maximal oxygen uptake were associated with SkyMarathon performance prediction.

Exercise attenuates dexamethasone-induced hypertension through an improvement of baroreflex activity independently of the renin-angiotensin system

Dexamethasone-induced hypertension may be caused by baroreflex alterations or renin-angiotensin system (RAS) exacerbation. Aerobic training has been recommended for hypertension treatment, but the mechanisms responsible for reduction of arterial pressure (AP) in dexamethasone (DEX) treated rats are still inconclusive.This study evaluated whether mechanisms responsible for training-induced attenuation of hypertension involve changes in autonomic nervous system and in RAS components. Rats underwent aerobic training protocol on treadmill or were kept sedentary for 8 weeks. Additionally, animals were treated with DEX during the last 10 days of exercise. Body weight (BW), AP and baroreflex activity were analyzed. Tibialis anterior (TA), soleus (SOL) and left ventricle (LV) were collected for evaluation of RAS components gene expression and protein levels. Dexamethasone decreased BW (20%), caused TA atrophy (16%) and increased systolic AP (SAP, 16%) as well as decreased baroreflex activity. Training attenuated SAP increase and improved baroreflex activity, although it did not prevent DEX-induced BW reduction and muscle atrophy. Neither DEX nor training caused expressive changes in RAS components. In conclusion, exercise training was effective in attenuating hypertension induced by DEX and this response may be mediated by a better autonomic balance through an improvement of baroreflex activity rather than changes in RAS components.

Exploring the Abnormal Modulation of the Autonomic Systems during Nasal Flow Limitation in Upper Airway Resistance Syndrome by Hilbert-Huang Transform.

A breath-by-breath investigation based on the Hilbert-Huang transform was performed to explore autonomic nervous system changes observed during inspiratory flow limitation. Autonomic status was quantified from beat-to-beat heart rate analysis by high frequency (RRHF; 0.15-0.4 Hz), low frequency (RRLF; 0.04-0.15 Hz), and LF/HF ratio of each respiratory cycle. Based on respiratory-related mechanisms contained in the PPG signal, we further quantified the respiratory-related oscillations (PPGres). Based on esophageal pressure and nasal flow measurements, each respiratory cycle was identified and breathing patterns were classified into one of four groups: normal, inspiratory flow limitation cycles without increased effort [FL(-)], minimal inspiratory flow limitation with effort, and inspiratory flow limitation cycles with increased effort [FL(+)]. The resulting quantitative parameters of the identified cycles were calculated. 49 UARS patients (12 males; aged 26.8 ± 5.8 years) with apnea-hypopnea index (AHI) 3.1 ± 1.5 per hour and nine aged matched control subjects (3 males; aged 27.8 ± 4.0 years) with AHI 0.8 ± 1.1 per hour were retrospectively identified. Compared to the control group, hyperactivation of the parasympathetic system was noted during stage 2 NREM sleep by RRHF (27.8 ± 18.2 vs 22.5 ± 11.12, p < 0.05) in 49 UARS patients. Analysis of the different classifications of respiratory cycles indicated that during "high" (increased) respiratory efforts, the RRHF and PPGres were significantly higher compared to "normal cycle" and "FL(-)" groups. The RRLF/RRHF (an index of sympathetic activity) was significantly lower in the "FL(+)" group (1.66 ± 0.80) than in the "normal cycle" (1.93 ± 0.97, p < 0.05) and "FL(-)" groups (2.01 ± 1.01, p < 0.05). The proposed algorithm allows quantifying the temporal changes of specific mechanisms of the autonomic system on breath-by-breath basis. With no or very limited impact on oxygen saturation, the hyperactivation of parasympathetic system in associated with inspiratory flow limitation or increased respiratory efforts during stage 2 NREM sleep has been presented in this study.

Vagal withdrawal and psychological distress during ventilator weaning and the related outcomes

ObjectiveThis study investigated the associations between changes in autonomic nervous system (ANS) function, psychological status during the mechanical ventilation (MV) weaning process, and weaning outcomes. MethodsIn this prospective study, we recruited 67 patients receiving MV for >24h at a medical center in northern Taiwan. Patients' ANS function, represented by heart rate variability (HRV), the rapid shallow breathing index (RSBI), anxiety, fear, and dyspnea, was repeatedly measured 10min before and 30min after undergoing a weaning trial. Forty-nine patients capable of sustaining a 2-h weaning trial were successfully weaned. ResultsCompared with the failed group, the success group showed significantly smaller decreases in high-frequency HRV (HRV-HF) and smaller increases in RSBI (per 10 breaths/min/L), fear, dyspnea, and anxiety in response to the weaning trial (odds ratio [OR]=2.19, 0.81, 0.69, 0.66, and 0.77, respectively; p<0.05). Multivariate analyses revealed that low-frequency HRV before weaning (OR=2.32; 95% confidence interval [CI]=1.13–4.78, p=0.02), changes in HRV-HF (OR=3.33; 95% CI=1.18–9.44, p=0.02), and psychological fear during the weaning process (OR=0.50; 95% CI=0.27–0.92, p=0.03) were three independent factors associated with 2-h T-piece weaning success. ConclusionsANS responses and psychological distress during weaning were associated with T-piece weaning outcomes and may reflect the need for future studies to utilize these factors to guide weaning processes and examine their impact on outcomes.

Regulating autonomic nervous system homeostasis improves pulmonary function in rabbits with acute lung injury

BackgroundThis study aimed to investigate the effects of regulating autonomic nervous system (ANS) homeostasis by inhibiting sympathetic hyperactivity and/or enhancing parasympathetic activity on pulmonary inflammation and functional disturbance.MethodsAn animal model of acute lung injury (ALI) was established in rabbits by an intratracheal injection of hydrochloric acid (HCl) in rabbits. Animals in control groups were received saline or HCl only, and the others received both HCl and followed treatments: vagus nerve stimulation (VNS), intravenous injection of tetrahydroaminoacridine (THA), or stellate ganglion block (SGB). The effects of different treatments on the changes in autonomic nervous system homeostasis, pulmonary and systemic inflammation, and functional disturbance were detected.ResultsSympathetic nervous activity was higher than parasympathetic nervous activity in rabbits after HCl aspiration, as demonstrated by the significant changes in the discharge frequency of cervical sympathetic/vagus trunk, and heart rate variability. VNS, THA and SGB could significantly alleviate the changes of ANS induced by HCl aspiration and improved the pulmonary function, especially for SGB treatment.ConclusionsThe disturbance of ANS homeostasis is attributed to a predominance of SNS activity. Administration of VNS, THA and SGB are capable to regulate disequilibrium of the ANS in rabbits with HCl-induced ALI and SGB is supposed to be the most effective approach.