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Mindfulness practice is beneficial for emotion regulation; however, the neural mechanisms underlying this effect are poorly understood. The current study focuses on effects of attention-to-breath (ATB) as a basic mindfulness practice on aversive emotions at behavioral and brain levels. A key finding across different emotion regulation strategies is the modulation of amygdala and prefrontal activity. It is unclear how ATB relevant brain areas in the prefrontal cortex integrate with amygdala activation during emotional stimulation. We proposed that, during emotional stimulation, ATB down-regulates activation in the amygdala and increases its integration with prefrontal regions. To address this hypothesis, 26 healthy controls were trained in mindfulness-based attention-to-breath meditation for two weeks and then stimulated with aversive pictures during both attention-to-breath and passive viewing while undergoing fMRI. Data were controlled for breathing frequency. Results indicate that (1) ATB was effective in regulating aversive emotions. (2) Left dorso-medial prefrontal cortex was associated with ATB in general. (3) A fronto-parietal network was additionally recruited during emotional stimulation. (4) ATB down regulated amygdala activation and increased amygdala–prefrontal integration, with such increased integration being associated with mindfulness ability. Results suggest amygdala–dorsal prefrontal cortex integration as a potential neural pathway of emotion regulation by mindfulness practice. •Attention to breath (ATB) reduces emotional responses in the amygdala.•Amygdala–prefrontal cortex functional connectivity increases during ATB.•Connectivity increase is linked with individual differences in mindful disposition.

Introduction The objective was to compare the impact of three assistance levels of different modes of mechanical ventilation; neurally adjusted ventilatory assist (NAVA), proportional assist ventilation (PAV), and pressure support ventilation (PSV) on major features of patient-ventilator interaction. Methods PSV, NAVA, and PAV were set to obtain a tidal volume (V T ) of 6 to 8 ml/kg (PSV 100 , NAVA 100 , and PAV 100 ) in 16 intubated patients. Assistance was further decreased by 50% (PSV 50 , NAVA 50 , and PAV 50 ) and then increased by 50% (PSV 150 , NAVA 150 , and PAV 150 ) with all modes. The three modes were randomly applied. Airway flow and pressure, electrical activity of the diaphragm (EAdi), and blood gases were measured. V T , peak EAdi, coefficient of variation of V T and EAdi, and the prevalence of the main patient-ventilator asynchronies were calculated. Results PAV and NAVA prevented the increase of V T with high levels of assistance (median 7.4 (interquartile range (IQR) 5.7 to 10.1) ml/kg and 7.4 (IQR, 5.9 to 10.5) ml/kg with PAV 150 and NAVA 150 versus 10.9 (IQR, 8.9 to 12.0) ml/kg with PSV 150 , P <0.05). EAdi was higher with PAV than with PSV at level 100 and level 150 . The coefficient of variation of V T was higher with NAVA and PAV (19 (IQR, 14 to 31)% and 21 (IQR 16 to 29)% with NAVA 100 and PAV 100 versus 13 (IQR 11 to 18)% with PSV 100 , P <0.05). The prevalence of ineffective triggering was lower with PAV and NAVA than with PSV ( P <0.05), but the prevalence of double triggering was higher with NAVA than with PAV and PSV ( P <0.05). Conclusions PAV and NAVA both prevent overdistention, improve neuromechanical coupling, restore the variability of the breathing pattern, and decrease patient-ventilator asynchrony in fairly similar ways compared with PSV. Further studies are needed to evaluate the possible clinical benefits of NAVA and PAV on clinical outcomes. Trial registration Clinicaltrials.gov NCT02056093 . Registered 18 December 2013.

Purpose of this study was to test utility of heart rate variability (HRV) in daily endurance exercise prescriptions. Twenty-six healthy, moderately fit males were randomized into predefined training group (TRA, n = 8), HRV-guided training group (HRV, n = 9), and control group (n = 9). Four-week training period consisted of running sessions lasting 40 min each at either low- or high-intensity level. TRA group trained on 6 days a week, with two sessions at low and four at high intensity. Individual training program for HRV group was based on individual changes in high-frequency R-R interval oscillations measured every morning. Increase or no change in HRV resulted in high-intensity training on that day. If there was significant decrease in HRV (below reference value [10-day mean-SD] or decreasing trend for 2 days), low-intensity training or rest was prescribed. Peak oxygen consumption (VO(2peak)) and maximal running velocity (Load(max)) were measured in maximal treadmill test before and after the training. In TRA group, Load(max) increased from 15.1 +/- 1.3 to 15.7 +/- 1.2 km h(-1) (P = 0.004), whereas VO(2peak) did not change significantly (54 +/- 4 pre and 55 +/- 3 ml kg(-1) min(-1) post, P = 0.224). In HRV group, significant increases were observed in both Load(max) (from 15.5 +/- 1.0 to 16.4 +/- 1.0 km h(-1), P < 0.001) and VO(2peak) (from 56 +/- 4 to 60 +/- 5 ml kg(-1) min(-1), P = 0.002). The change in Load(max) was significantly greater in HRV group compared to TRA group (0.5 +/- 0.4 vs. 0.9 +/- 0.2 km h(-1), P = 0.048, adjusted for baseline values). No significant differences were observed in the changes of VO(2peak) between the groups. We concluded that cardiorespiratory fitness can be improved effectively by using HRV for daily training prescription.

Background Adaptive mechanical ventilation automatically adjusts respiratory rate (RR) and tidal volume ( V T ) to deliver the clinically desired minute ventilation, selecting RR and V T based on Otis’ equation on least work of breathing. However, the resulting V T may be relatively high, especially in patients with more compliant lungs. Therefore, a new mode of adaptive ventilation (adaptive ventilation mode 2, AVM2) was developed which automatically minimizes inspiratory power with the aim of ensuring lung-protective combinations of V T and RR. The aim of this study was to investigate whether AVM2 reduces V T , mechanical power, and driving pressure (Δ P stat ) and provides similar gas exchange when compared to adaptive mechanical ventilation based on Otis’ equation. Methods A prospective randomized cross-over study was performed in 20 critically ill patients on controlled mechanical ventilation, including 10 patients with acute respiratory distress syndrome (ARDS). Each patient underwent 1 h of mechanical ventilation with AVM2 and 1 h of adaptive mechanical ventilation according to Otis’ equation (adaptive ventilation mode, AVM). At the end of each phase, we collected data on V T , mechanical power, Δ P , PaO 2 /FiO 2 ratio, PaCO 2 , pH, and hemodynamics. Results Comparing adaptive mechanical ventilation with AVM2 to the approach based on Otis’ equation (AVM), we found a significant reduction in V T both in the whole study population (7.2 ± 0.9 vs. 8.2 ± 0.6 ml/kg, p  <  0.0001) and in the subgroup of patients with ARDS (6.6 ± 0.8 ml/kg with AVM2 vs. 7.9 ± 0.5 ml/kg with AVM, p  <  0.0001). Similar reductions were observed for Δ P stat (whole study population: 11.5 ± 1.6 cmH 2 O with AVM2 vs. 12.6 ± 2.5 cmH 2 O with AVM, p  <  0.0001; patients with ARDS: 11.8 ± 1.7 cmH 2 O with AVM2 and 13.3 ± 2.7 cmH 2 O with AVM, p  = 0.0044) and total mechanical power (16.8 ± 3.9 J/min with AVM2 vs. 18.6 ± 4.6 J/min with AVM, p  = 0.0024; ARDS: 15.6 ± 3.2 J/min with AVM2 vs. 17.5 ± 4.1 J/min with AVM, p  = 0.0023). There was a small decrease in PaO 2 /FiO 2 (270 ± 98 vs. 291 ± 102 mmHg with AVM, p  = 0.03; ARDS: 194 ± 55 vs. 218 ± 61 with AVM, p  = 0.008) and no differences in PaCO 2 , pH, and hemodynamics. Conclusions Adaptive mechanical ventilation with automated minimization of inspiratory power may lead to more lung-protective ventilator settings when compared with adaptive mechanical ventilation according to Otis’ equation. Trial registration The study was registered at the German Clinical Trials Register ( DRKS00013540 ) on December 1, 2017, before including the first patient.

Objective To compare the effect of heated, humidified, high-flow nasal cannula (HHHFNC) and nasal continuous positive airways pressure (NCPAP) on lung function and mechanics in preterm infants with respiratory distress syndrome (RDS) at the same level of retropharyngeal pressure (Prp). Design Randomised crossover trial. Setting Neonatal intensive care unit, Ospedale Maggiore Policlinico, Milan, Italy. Patients 20 preterm infants (gestational age: 31±1 wks) with mild-moderate RDS requiring non-invasive respiratory support within 96 h after birth. Interventions Infants were exposed to a randomised sequence of NCPAP and HHHFNC at different settings (2, 4 and 6 cmH2O for NCPAP and 2, 4, 6 L/min for HHHFNC) to enable comparison at the same level of Prp. Main outcome measures Tidal volume by respiratory inductance plethysmography, pleural pressure estimated by oesophageal pressure, and gas exchange were evaluated at each setting and used to compute breathing pattern parameters, lung mechanics and work of breathing (WOB). Results A poor linear regression between flow and Prp was found during HHHFNC (Prp=0.3+0.7*flow; r2=0.37). Only in 15 out of 20 infants it was possible to compare HHHFNC and NCPAP at a Prp of 2 and 4 cmH2O. No statistically significant differences were found in breathing pattern, gas exchange, lung mechanics and total WOB. Resistive WOB in the upper airways was slightly but significantly higher during HHHFNC (0.65 (0.49;1.09) vs 1.57 (0.85;2.09) cmH2O median (IQR)). Conclusions Despite differing mechanisms for generating positive airway pressure, when compared at the same Prp, NCPAP and HHHFNC provide similar effects on all the outcomes explored.

Prone positioning with continuous positive airway pressure (CPAP) is widely used for respiratory support in awake patients with COVID-19-associated acute respiratory failure. We aimed to assess the respiratory mechanics and distribution of ventilation in COVID-19-associated ARDS treated by CPAP in awake prone position. We studied 16 awake COVID-19 patients with moderate-to-severe ARDS. The study protocol consisted of a randomized sequence of supine and prone position with imposed positive end-expiratory pressure (PEEP) of 5 and 10 cmH2O delivered by helmet CPAP. Respiratory mechanics and distribution of ventilation were assessed through esophageal pressure (PES) and electrical impedance tomography (EIT). At the end of each 20-min phase, arterial blood gas analysis was performed, and PES swing and EIT tracings were recorded for the calculation of the respiratory mechanics and regional ventilation. The patient’s position had no significant effects on respiratory mechanics. EIT analysis did not detect differences among global indices of ventilation. A significant proportion of pixels in the sternal region of interest showed an increase in compliance from the supine to prone position and PaO2/FIO2 increased accordingly. The best improvement of both PaO2/FIO2 and sternal compliance was obtained in the prone position with PEEP 10 cmH2O. In the studied subjects, prone positioning during CPAP treatment raised oxygenation without improvement of “protective” ventilation or global ventilatory inhomogeneity indices. Prone positioning with higher PEEP significantly increased the compliance of sternal regions.

Muscle wasting frequently occurs in severe emphysema. Improving respiratory mechanics by bronchoscopic lung volume reduction using endobronchial valves (EBV) might prevent further loss or even increase in muscle mass. CT-derived skeletal muscle mass gain was observed in 39/49 patients 6 months after EBV. Multiple linear regression showed that gain in muscle (β=2.4; 95% CI 0.2 to 4.6; p=0.036) and intramuscular fat (β=3.1; 95% CI 0.2 to 5.9; p=0.035) is associated with improved 6 min walk distance independent of the change in residual volume. Skeletal muscle remodelling associates with improved exercise capacity after EBV, independent of hyperinflation reduction.Trial registration numberClinical trial registered with the Dutch trial register www.trialregister.nl (NTR2876), Results.

Background In obese patients, high closing capacity and low functional residual capacity increase the risk for expiratory alveolar collapse. Constant expiratory flow, as provided by the new flow-controlled ventilation (FCV) mode, was shown to improve lung recruitment. We hypothesized that lung aeration and respiratory mechanics improve in obese patients during FCV. Methods We compared FCV and volume-controlled (VCV) ventilation in 23 obese patients in a randomized crossover setting. Starting with baseline measurements, ventilation settings were kept identical except for the ventilation mode related differences (VCV: inspiration to expiration ratio 1:2 with passive expiration, FCV: inspiration to expiration ratio 1:1 with active, linearized expiration). Primary endpoint of the study was the change of end-expiratory lung volume compared to baseline ventilation. Secondary endpoints were the change of mean lung volume, respiratory mechanics and hemodynamic variables. Results The loss of end-expiratory lung volume and mean lung volume compared to baseline was lower during FCV compared to VCV (end-expiratory lung volume: FCV, − 126 ± 207 ml; VCV, − 316 ± 254 ml; p  < 0.001, mean lung volume: FCV, − 108.2 ± 198.6 ml; VCV, − 315.8 ± 252.1 ml; p  < 0.001) and at comparable plateau pressure (baseline, 19.6 ± 3.7; VCV, 20.2 ± 3.4; FCV, 20.2 ± 3.8 cmH 2 O; p  = 0.441), mean tracheal pressure was higher (baseline, 13.1 ± 1.1; VCV, 12.9 ± 1.2; FCV, 14.8 ± 2.2 cmH 2 O; p  < 0.001). All other respiratory and hemodynamic variables were comparable between the ventilation modes. Conclusions This study demonstrates that, compared to VCV, FCV improves regional ventilation distribution of the lung at comparable PEEP, tidal volume, P Plat and ventilation frequency. The increase in end-expiratory lung volume during FCV was probably caused by the increased mean tracheal pressure which can be attributed to the linearized expiratory pressure decline. Trial registration German Clinical Trials Register: DRKS00014925 . Registered 12 July 2018.

Background The peak inspiratory pressure (PIP) is crucial in mechanical ventilation with supraglottic airway device (SAD). Pressure-controlled ventilation volume-guaranteed (PCV-VG), delivering a preset tidal volume with the lowest required airway pressure, is being increasingly used during general anesthesia. In this study, we compared respiratory mechanics and circulatory parameters between volume-controlled ventilation (VCV) and PCV-VG in elderly patients undergoing laparoscopic surgery using the laryngeal mask airway supreme (LMA). Methods Eighty participants scheduled for laparoscopic surgery were enrolled in this prospective, randomized clinical trial. The participants were randomly assigned to receive VCV or PCV-VG. PIP, dynamic compliance (Cdyn) and mean inspiratory pressure (Pmean) were recorded at 5 min after induction of anesthesia (T1), 5 min after pneumoperitoneum(T2), 30 and 60 min after pneumoperitoneum (T3 and T4). Data including other respiratory variables, hemodynamic variables, and arterial blood gases were also collected. The difference in PIP between VCV and PCV-VG was assessed as the primary outcome. Results PIP was significantly lower at T2, T3, and T4 in both groups compared with T1 (all P  <  0.0001), and it was significantly lower in the PCV-VG group than the VCV group at T2, T3, and T4 (all P  <  0.001). Cydn was decreased at T2, T3, and T4 in two groups compared with T1 (all P  <  0.0001), but it was higher in PCV-VG group than in VCV group at T2, T3, and T4 (all P  <  0.0001). There were on statistically significant differences were found between the groups for other respiratory and hemodynamic variables. Conclusion In elderly patients who underwent laparoscopic surgery using an LMA, PCV-VG was superior to VCV in its ability to provide ventilation with lower peak inspiratory pressure and greater dynamic compliance.

Purpose The purposes of this experiment were to, first, document the effect of 45-kg thoracic loading on peak exercise responses and, second, the effects of systematic increases in thoracic load on physiological responses to submaximal treadmill walking at a standardized speed and grade. Methods On separate days, 19 males (age 27 ± 5 years, height 180.0 ± 7.4 cm, mass 86.9 ± 15.1 kg) completed randomly ordered graded exercise tests to exhaustion in loaded (45 kg) and unloaded conditions. On a third day, each subject completed four randomly ordered, 10-min bouts of treadmill walking at 1.34 m s −1 and 4 % grade in the following conditions: unloaded, and with backpacks weighted to 15, 30, and 45 kg. Results With 45-kg thoracic loading, absolute oxygen consumption ( V ˙ O 2 ), minute ventilation, power output, and test duration were significantly decreased at peak exercise. End-inspiratory lung volume and tidal volume were significantly reduced with no changes in end-expiratory lung volume, breathing frequency, and the respiratory exchange ratio. Peak end-tidal carbon dioxide and the ratio of alveolar ventilation to carbon dioxide production were similar between conditions. The reductions in peak physiological responses were greater than expected based on previous research with lighter loads. During submaximal treadmill exercise, V ˙ O 2 increased ( P  < 0.05) by 11.0 (unloaded to 15 kg), 14.5 (15–30 kg), and 18.0 % (30–45 kg) showing that the increase in exercise V ˙ O 2 was not proportional to load mass. Conclusion These results provide further insight into the specificity of physiological responses to different types of load carriage.