Baroreflex dynamics during the rest to exercise transient in acute normobaric hypoxia in humans

Purpose We hypothesised that during a rest-to-exercise transient in hypoxia (H), compared to normoxia (N), (i) the initial baroreflex sensitivity (BRS) decrease would be slower and (ii) the fast heart rate (HR) and cardiac output (CO) response would have smaller amplitude (A(1)) due to lower vagal activity in H than N. Methods Ten participants performed three rest-to-50 W exercise transients on a cycle-ergometer in N (ambient air) and three in H (inspired fraction of O-2 = 0.11). R-to-R interval (RRi, by electrocardiography) and blood pressure profile (by photo-plethysmography) were recorded non-invasively. Analysis of the latter provided mean arterial pressure (MAP) and stroke volume (SV). CO = HRSV. BRS was calculated by modified sequence method. Results Upon exercise onset in N, MAP fell to a minimum (MAPmin) then recovered. BRS decreased immediately from 14.7 +/- 3.6 at rest to 7.0 +/- 3.0 ms mmHg(-1) at 50 W (p < 0.01). The first BRS sequence detected at 50 W was 8.9 +/- 4.8 ms mmHg(-1) (p < 0.05 vs. rest). In H, MAP showed several oscillations until reaching a new steady state. BRS decreased rapidly from 10.6 +/- 2.8 at rest to 2.9 +/- 1.5 ms mmHg(-1) at 50 W (p < 0.01), as the first BRS sequence at 50 W was 5.8 +/- 2.6 ms mmHg(-1) (p < 0.01 vs. rest). CO-A(1) was 2.96 +/- 1.51 and 2.31 +/- 0.94 l min(-1) in N and H, respectively (p = 0.06). HR-A(1) was 7.7 +/- 4.6 and 7.1 +/- 5.9 min(-1) in N and H, respectively (p = 0.81). Conclusion The immediate BRS decrease in H, coupled with similar rapid HR and CO responses, is compatible with a withdrawal of residual vagal activity in H associated with increased sympathetic drive

Cardiovascular responses during rest-exercise and exercise-exercise transients

If indeed vagal withdrawal determines the rapid response to exercise (phase I), the a large reduction, if not complete suppression, of phase I should be found, when an exercise transient starts from a previous lower steady state exercise rather than from rest. On 15 healthy young subjects we measured beat-by-beat cardiac output (Q̇, Modelflow from Portapres data) and heart rate (fH, ECG) during these cycle ergometer exercise transients: 0–50 W (transient from rest, RT) and 50–100W (transient from exercise, ET). A double exponential was used to compute amplitudes and time constants of phase I and II (A1 and A2; T1 and T2). At steady state, fH was 87.510.4, 109.312.0, and 139.617.1bpm, and Q̇ was 7.31.5, 12.61.6, and 16,11,9L/min, at rest, 50W and 100W, respectively. In RT, A1 and A2 for fH were 11.78.6 and 11.34.7bpm; the corresponding T1 and T2 were 1.61.9 and 14.421.3s. For Q̇, we had: A1=4.01.8L/min, A2=1.51.4L/min, T1=3.21.8s, T2=11.312.2s. In ET, the double exponential model provided preposterous A1 and T1 values and extremely high T2 values (&gt;100s). Subsequent use of a mono exponential model provided, for fH, A=29.78.9bpm and T=7.74.9s, and for Q̇, A=3.58.6L/min, and T=7.05.7s. The A and T in ET did not differ from the A2 and T2 of RT. We conclude that a single exponential model is more adequate to describe ET and this single exponential corresponds to the second exponential of RT. Our results are compatible with the vagal withdrawal hypothesis

LIFESTYLE ASSESSMENT AND IMPROVEMENT WITH FOCUS ON LEISURE TIME PHYSICAL ACTIVITY AMONG UNIVERSITY STUDENTS: THE #STUDIOXLAVITA PROJECT

INTRODUCTION: Sedentariness, smoking, alcohol abuse and unbalanced feeding are harmful for health, leading to chronic diseases and increasing mortality rate. For young adults, University is a new social and cultural context: parents’ imprinting could be easily altered, new lifestyles take shape and personal choices emerge. Intervention programmes to advance awareness on harmful lifestyle and promote healthy habits are essential. The #studioxlavita project, launched in 2016 by the University of Brescia with these purposes, investigated students’ lifestyle, with special emphasis on physical activity . METHODS: We developed two consecutive facultative surveys, of 15 &lt;1st level&gt; and 52 items &lt;2nd level&gt;, addressed to all the University’s students. Questions were about leisure time physical activity , use of fitness technology, relationship with friends, classmates and parents, feed, physical appearance, body self-perception, physical and mental health, use of certain substances or products , night-time rest and beliefs concerning healthy behaviours. In the 2nd level survey we also adopted the Kessler Psychological Distress Scale and the short form of the International Physical Activity Questionnaire to estimate the amount of PA carried out in the last 7 days. Students who filled in both questionnaires received a personal report including the aggregate data analysis, a comparison with other investigations and indications about healthy habits, according to recommendations and guidelines. RESULTS: 3,436 out of 15,688 students filled in the1st level survey. Of them, 778 accepted to participate in the 2nd level survey, and 456 completed it. 1st level survey revealed that 72% of the students practised LTPA &lt;45% regularly and 27% occasionally&gt;. LTPA is largely performed &lt;44% of the student&gt; in non-competitive form, with recreational and/or health purposes. According to IPAQ-SF categorical score, 24%, 34% and 42% of the students performed low, moderate and high levels of PA, respectively. In 2st level survey, 76% of the students wished to practise more PA; 42% would participate in practical sport courses. CONCLUSION: University is an ideal setting for promoting lifestyle change among a captive audience. Intervention programs to increment PA are acclaimed by students. The students from University of Brescia reported higher LTPA practice than the national average people between 18 and 34 years &lt;47%, data from Italian National Institute of Statistics, 2015&gt;, although this parameter was assessed with different methods

EFFECTS OF PHYSICAL ACTIVITY PROMOTION AMONG UNIVERSITY STUDENTS: THE #STUDIOXLAVITA PROJECT

INTRODUCTION: Sedentariness is a major health problem in our time and physical activity promotion is an imperative commitment for healthcare systems. Recommendations from WHO indicate a minimum of 150 minutes of moderate intensity aerobic exercise as weekly standard for adults. Strategies to increment PA practice are implemented in different settings, such as house care, school, University and workplace. The project #studioxlavita &lt;#SXLV&gt; was launched by the University of Brescia in 2016 with the aim of collecting data about undergraduates lifestyle and encourage healthy behaviours. In particular we focused on PA assessment and promotion in a Universitybased setting. METHODS: Two consecutive surveys were sent to all students . Q0 included the short form of the International Physical Activity Questionnaire , the Kessler Psychological Distress Scale and additional questions on several lifestyle aspects. Among responders, we selected 40 students who agreed to take part in one of the following 15-week practical sport courses: ultimate frisbee, muscle strengthening and dance fitness. Before and after being engaged in practical sport courses, students underwent cardiopulmonary exercise test and skinfold thickness measurements, in order to assess peak oxygen consumption and percent body fat . Finally, to assess possible lifestyle changes, we sent them additional surveys at the end of the practical sport courses and 30 days after . Paired t-test was used to analyse significant differences. RESULTS: 27 students &lt;16 female, 11 male; age: 22.7±3.7&gt; concluded sport activity courses and filled in Q1. Of them, 20 completed also Q2. Overall courses attendance was 57%. At T1 , normalized Q̇O2peak increased with respect to T0 &lt;37.0±6.9 vs 35.2±7.4 ml/min/Kg, p=0.03&gt;. Conversely, percent body fat decreased &lt;16.5±6.4 vs 18.3±7.5, p=0.01&gt;. In Q1, 20 students declared to have a more active lifestyle since the beginning of the courses. In Q2, IPAQ-SF-derived total weekly energy expenditure was higher than in Q0, although not significant &lt;5,839 ±7,035 MET*min vs 2,770±2,457 MET*min, p=0.1&gt;. Q2 showed a reduced K6 scale score with respect to Q0 &lt;13.8±4.6 vs 15.8±4.9, p=0.03&gt;. CONCLUSION: With the sport activity courses established in #SXLV we gave students the opportunity to comply with WHO recommendations. After courses, they appeared to practice more PA, have a higher maximal aerobic capacity, a lower percent body fat and a lower grade of psychological distress than before courses. Simple activities as those proposed by #SXLV are sufficient to reduce sedentariness and improve the quality of life of student

The effect of lower body negative pressure on phase 1 cardiovascular responses at exercise onset in healthy humans

We tested the hypothesis that vagal withdrawal and increased venous return interact in determining the rapid cardiac output response (Phase I) at exercise onset. We used lower body negative pressure (LBNP) to increase blood dislocation to the heart by muscle pump action and simultaneously reduce resting vagal activity. At exercise start, we expected larger response amplitude for stroke volume and smaller for heart rate at progressively stronger LBNP levels, so that the cardiac output response would remain unchanged. Ten subjects performed 50 W exercise supine in Control condition and during -45 mmHg LBNP exposure. On single beat basis, we measured heart rate (HR), stroke volume (SV), and we calculated cardiac output (CO). We computed Phase I response amplitudes (A1) using an exponential model. SV A1 was higher under LBNP than in Control (p &lt; 0.05). Conversely, the A1 of HR, was 23 ± 56 % lower under LBNP than in Control (although NS). Since these changes tended to compensate each other, the A1 for CO was unaffected by LBNP. The rapid SV kinetics at exercise onset is compatible with an effect of increased venous return, whereas the vagal withdrawal conjecture cannot be dismissed for HR kinetics. The rapid CO response may indeed be the result of two independent yet parallel mechanisms, as hypothesized, one acting on SV, the other on H

Small Nerve Fiber Pathology in Critical Illness

BACKGROUND: Degeneration of intraepidermal nerve fibers (IENF) is a hallmark of small fiber neuropathy of different etiology, whose clinical picture is dominated by neuropathic pain. It is unknown if critical illness can affect IENF. METHODS: We enrolled 14 adult neurocritical care patients with prolonged intensive care unit (ICU) stay and artificial ventilation ( 65 3 days), and no previous history or risk factors for neuromuscular disease. All patients underwent neurological examination including evaluation of consciousness, sensory functions, muscle strength, nerve conduction study and needle electromyography, autonomic dysfunction using the finger wrinkling test, and skin biopsy for quantification of IENF and sweat gland innervation density during ICU stay and at follow-up visit. Development of infection, sepsis and multiple organ failure was recorded throughout the ICU stay. RESULTS: Of the 14 patients recruited, 13 (93%) had infections, sepsis or multiple organ failure. All had severe and non-length dependent loss of IENF. Sweat gland innervation was reduced in all except one patient. Of the 7 patients available for follow-up visit, three complained of diffuse sensory loss and burning pain, and another three showed clinical dysautonomia. CONCLUSIONS: Small fiber pathology can develop in the acute phase of critical illness and may explain chronic sensory impairment and pain in neurocritical care survivors. Its impact on long term disability warrants further studies involving also non-neurologic critical care patients

Worldwide Survey of the "Assessing Pain, Both Spontaneous Awakening and Breathing Trials, Choice of Drugs, Delirium Monitoring/Management, Early Exercise/Mobility, and Family Empowerment" (ABCDEF) Bundle

OBJECTIVES: To assess the knowledge and use of the Assessment, prevention, and management of pain; spontaneous awakening and breathing trials; Choice of analgesia and sedation; Delirium assessment; Early mobility and exercise; and Family engagement and empowerment (ABCDEF) bundle to implement the Pain, Agitation, Delirium guidelines. DESIGN: Worldwide online survey. SETTING: Intensive care. INTERVENTION: A cross-sectional online survey using the Delphi method was administered to intensivists worldwide, to assess the knowledge and use of all aspects of the ABCDEF bundle. MEASUREMENT AND MAIN RESULTS: There were 1,521 respondents from 47 countries, 57% had implemented the ABCDEF bundle, with varying degrees of compliance across continents. Most of the respondents (83%) used a scale to evaluate pain. Spontaneous awakening trials and spontaneous breathing trials are performed in 66% and 67% of the responder ICUs, respectively. Sedation scale was used in 89% of ICUs. Delirium monitoring was implemented in 70% of ICUs, but only 42% used a validated delirium tool. Likewise, early mobilization was "prescribed" by most, but 69% had no mobility team and 79% used no formal mobility scale. Only 36% of the respondents assessed ICU-acquired weakness. Family members were actively involved in 67% of ICUs; however, only 33% used dedicated staff to support families and only 35% reported that their unit was open 24 hr/d for family visits. CONCLUSIONS: The current implementation of the ABCDEF bundle varies across individual components and regions. We identified specific targets for quality improvement and adoption of the ABCDEF bundle. Our data reflect a significant but incomplete shift toward patient- and family-centered ICU care in accordance with the Pain, Agitation, Delirium guidelines

Neuromuscular disorders and neuromuscular acquired neuromuscular weakness

Un testo di riferimento per le condizioni patologiche di più frequente riscontro nell'ambito della Neurorianimazione, sia riguardo a patologie del sistema nervoso centrale che di quello periferico e dei muscol

Neuromuscular Electrical Stimulation in Critically Ill Patients

The intensive care unit acquired weakness (ICUAW) is one of the most frequently complications after ICU admission. The resulting sequelae may occur even years after discharge from the ICU, unfortunately there are scanty data about effectively treatment that can counteract the muscle deconditioning. Neuromuscular electrical stimulation (NMES), widely used for several purposes, aims to maintain muscle trophism and function in critically ill patients. NMES may also be used as a diagnostic tool, that can provide important information on the muscle state. This chapter provides the basic concepts, physiological mechanisms of NMES, and the latest evidence in the treatment of sepsis and acute respiratory failure, proposing an algorithm, and focusing on the proper execution of this physical therapy