Browsing by Subject "Heart rate"

Now showing 1 - 6 of 6
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    Characterization of the relationship between spontaneous locomotor activity and cardiovascular parameters in conscious freely moving rats
    (Elsevier, 2016-02) Zaretsky, Dmitry V.; Zaretskaia, Maria V.; DiMicco, Joseph A.; Department of Emergency Medicine, IU School of Medicine
    In freely behaving rats, variations in heart rate (HR) and blood pressure (BP) are coupled closely with changes in locomotor activity (Act). We have attempted to characterize this relationship mathematically. In 10- and 16-week-old rats, HR, BP and Act were recorded telemetrically every minute for 2 days under 12h:12h light-dark cycling. After examining data for individual rats, we found that the relationship between Act and HR could be approximated by the negative exponential function HR(Act)=HRmax-(HRmax-HRmin)∗exp(-Act/Acte), where HRmax, HRmin, and Acte are constants. These constants were calculated separately for light and dark periods by non-linear curve fitting. HR corresponding to maximal locomotion was similar during the light and dark phases, while HR at rest during the dark phase was higher than during the light phase. The range of HR variability associated with Act during the dark phase was similar in young and older animals, but minimal HR was significantly lower in older rats. The relationship between Act and BP was approximated with a similar function. We have found no differences between BP at rest and at maximal locomotion between light and dark and between 10-week and 16-week-old rats. Our results indicate that in rats, cardiovascular parameters are coupled to locomotion to a high degree; however both the HR and the BP reach maximal values when locomotor activity is relatively low. We also found that the phase of daily cycle affects HR in conscious rats independent of locomotor activity.
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    Electronic Heart (ECG) Monitoring at Birth and Newborn Resuscitation
    (MDPI, 2024-06-04) Mende, Sarah; Ahmed, Syed; DeShea, Lise; Szyld, Edgardo; Shah, Birju A.; Pediatrics, School of Medicine
    Background: Approximately 10% of newborns require assistance at delivery, and heart rate (HR) is the primary vital sign providers use to guide resuscitation methods. In 2016, the American Heart Association (AHA) suggested electrocardiogram in the delivery room (DR-ECG) to measure heart rate during resuscitation. This study aimed to compare the frequency of resuscitation methods used before and after implementation of the AHA recommendations. Methods: This longitudinal retrospective cohort study compared a pre-implementation (2015) cohort with two post-implementation cohorts (2017, 2021) at our Level IV neonatal intensive care unit. Results: An initial increase in chest compressions at birth associated with the introduction of DR-ECG monitoring was mitigated by focused educational interventions on effective ventilation. Implementation was accompanied by no changes in neonatal mortality. Conclusions: Investigation of neonatal outcomes during the ongoing incorporation of DR-ECG may help our understanding of human and system factors, identify ways to optimize resuscitation team performance, and assess the impact of targeted training initiatives on clinical outcomes.
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    Impact of Opioid and Nonopioid Drugs on Postsurgical Pain Management in the Rat
    (Hindawi Publishing Corporation, 2016) Wilson, Natalie M.; Ripsch, Matthew S.; White, Fletcher A.; Department of Anesthesia, IU School of Medicine
    Aim. Nonsteroidal anti-inflammatory drugs or opioids are commonly used to control surgical pain following veterinary and clinical procedures. This study evaluated the efficacy of postoperative ketorolac or buprenorphine following abdominal surgery. Main Methods. Mean arterial pressure (MAP), heart rate, animal activity, corticosterone levels, and a nociceptive sensitivity assay were used to evaluate 18 adult male Sprague-Dawley rats which underwent aortic artery occlusion for implantation of a radiotelemetry device. The animals were treated postoperatively with intraperitoneal injections of vehicle, ketorolac (10 mg/kg), or buprenorphine (0.06 mg/kg) every 8 hours for 3 days. Key Findings. There were no consistent significant changes in any of the telemetry parameters after treatment with ketorolac compared with no saline treatment with the exception of increased MAP in the buprenorphine group during the first 48 hours when compared with other treatment groups. There was a sustained increase in fecal corticosterone levels from baseline on days 2-7 with buprenorphine compared with vehicle- or ketorolac-treated animals. All treatment conditions displayed reduced paw withdrawal thresholds (PWTs) from day 1 to day 21 following surgery. Compared with the vehicle treatment group, buprenorphine-treated animals exhibited significantly lower PWT levels from day 4 to 14 days. Significance. Given the prolonged increase in fecal corticosterone levels and pronounced changes in tactile hyperalgesia behavior in rodents subjected to buprenorphine treatment, these data suggest that ketorolac may be superior to buprenorphine for the treatment of postprocedure pain behavior in rodents.
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    Neural Functional Connectivity Changes to Psychosocial Stress in Young Adults with Bipolar Disorder and Preliminary Associations with Clinical Trajectories
    (Wiley, 2022) Kirsch, Dylan E.; Preston, Alex; Tretyak, Valeria; Le, Vanessa; Weber, Wade; Strakowski, Stephen M.; Lippard, Elizabeth T. C.; Psychiatry, School of Medicine
    Background: Stress-related mechanisms are implicated in the pathophysiology of bipolar disorder and may contribute to heterogeneity in illness course. Yet, there is a lack of study investigating the neural mechanisms underlying the stress response in this condition. This study investigated changes in amygdala activation and functional connectivity in response to acute psychosocial stress in young adults with bipolar disorder and explored relations with clinical phenotype and prospective mood symptoms. Methods: 42 young adults [19 with bipolar disorder, agemean ± SD =21.4 ± 2.2 years] completed a modified version of the Montreal Imaging Stress Task. Amygdala activation and functional connectivity with prefrontal cortex (PFC) regions of interest was calculated for control and stress conditions. Main effects of group, condition, and group by condition interaction on amygdala activation and connectivity were modeled. A subset of bipolar participants completed 1-year follow-up assessments. Relations between neural responses to stress with concurrent substance use and prospective mood symptoms were explored. Results: There were no between-group differences in amygdala activation or functional connectivity during the control condition. Increased right amygdala-right rostral PFC (rPFC) functional connectivity to stress was observed in bipolar disorder, compared to typically developing controls. In bipolar disorder, greater increase in right amygdala-right rPFC functional connectivity to stress was associated with less frequent cannabis use, and prospectively with shorter duration and lower severity of depression symptoms over follow-up. Conclusion: Results from this preliminary study suggest differences in frontolimbic functional connectivity responses to stress in young adults with bipolar disorder and associations with cannabis use and prospective mood symptoms.
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    Skin Sympathetic Nerve Activity as a Biomarker of Fitness
    (Elsevier, 2021) Liu, Xiao; Kumar, Awaneesh; O’Neil, Joseph; Wong, Johnson; Saadoon, Osama; Kadire, Siri; Mitscher, Gloria A.; Li, Xiaochun; Chen, Peng-Sheng; Emery, Michael S.; Everett, Thomas H., IV; Biostatistics, School of Public Health
    Background: Exercise stress testing is frequently used to expose cardiac arrhythmias. Aerobic exercise conditioning has been used as a nonpharmacologic antiarrhythmic intervention. Objective: The purpose of this study was to test the hypothesis that noninvasively recorded skin sympathetic nerve activity (SKNA) is increased during exercise and that SKNA response varies according to fitness levels. Methods: Oxygen consumption (VO2) and SKNA were recorded in 39 patients undergoing an incremental exercise test. Patients were grouped by 5 levels of fitness based on age, sex, and VO2max. Results: With exercise, all patients had a significant increase in average SKNA (aSKNA) (1.58 ± 1.12 μV to 4.50 ± 3.06 μV, P = .000) and heart rate (HR) (87.40 ± 20.42 bpm to 154.13 ± 16.82 bpm, P = .000). A mixed linear model of aSKNA was used with fixed effects of fitness, exercise time, and recovery time, and random effects of subject level intercept and slopes for exercise time and recovery times. The poor fitness group had significantly higher aSKNA than the other groups (P = .0273). For all subjects studied, aSKNA increased by 5% per minute with progression of exercise and decreased by 15% per minute with progression of recovery. The fitness variable encodes information on both comorbidities and body mass index (BMI). Once fitness level is known, comorbidities and BMI are not significantly associated with aSKNA. In all groups, aSKNA positively correlated with HR (R2 = 0.47 ± 0.23) and VO2 (R2 = 0.68 ± 0.25). Conclusion: Fitness level determines the magnitude and time course of SKNA increase during exercise. SKNA may be a useful fitness biomarker in exercise stress testing.
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    The acute hypoalgesic effects of active head-mounted display virtual reality games
    (Public Library of Science, 2024-08-14) Naugle, Keith E.; Cervantes, Xzaliya A.; Boone, Carolyn L.; Wind, Brandon; Naugle, Kelly M.; Exercise & Kinesiology, School of Health and Human Sciences
    The purpose of this study was to determine: (1) whether physically active virtual reality (VR) games exert an acute hypoaglesic effect on the thigh and bicep compared to a non-active VR game and an exercise only condition matched for exercise intensity in healthy individuals, and (2) whether movement variables during gameplay are associated with the hypoalgesic effect of the games. Twenty young adults completed five separate study sessions, with each session devoted to playing one head-mounted display VR game or stationary cycling for 15 minutes. The games included Holopoint at level 2 and level 3, Hot Squat, and Relax Walk. Pressure pain thresholds at the thigh and bicep were measured pre and post VR gameplay and cycling. Participants wore a heart rate monitor and accelerometers on the wrist and thigh during play to measure the intensity and quantity of movement. Repeated measures ANOVAs revealed that pressure pain thresholds on the bicep increased from pre to posttest for each condition. The results also revealed that pressure pain thresholds on the thigh increased only for the conditions eliciting the greatest cardiovascular response, which included Holopoint at level 3, Hot Squat, and cycling. Bivariate correlations indicated that moderate to vigorous physical activity of the thigh was associated with pain reduction at the thigh during Holopoint. These results revealed that active VR games and exercise exerted a more widespread hypoalgesic effect compared to the non-active VR game, which was likely driven in part by the intensity and quantity of movement during gameplay.