Abdominal Binding Improves Neuromuscular Efficiency of the Human Diaphragm during Exercise

Outcomes of different pulmonary rehabilitation protocols in patients under mechanical ventilation with difficult weaning: a retrospective cohort study

BACKGROUND

The endeavor of liberating patients from ventilator dependence within respiratory care centers (RCCs) poses considerable challenges. Multiple factors contribute to this process, yet establishing an effective regimen for pulmonary rehabilitation (PR) remains uncertain. This retrospective study aimed to evaluate existing rehabilitation protocols, ascertain associations between clinical factors and patient outcomes, and explore the influence of these protocols on the outcomes of the patients to shape suitable rehabilitation programs.

METHODS

Conducted at a medical center in northern Taiwan, the retrospective study examined 320 newly admitted RCC patients between January 1, 2015, and December 31, 2017. Each patient received a tailored PR protocol, following which researchers evaluated weaning rates, RCC survival, and 3-month survival as outcome variables. Analyses scrutinized differences in baseline characteristics and prognoses among three PR protocols: protocol 1 (routine care), protocol 2 (routine care plus breathing training), and protocol 3 (routine care plus breathing and limb muscle training).

RESULTS

Among the patients, 28.75% followed protocol 1, 59.37% protocol 2, and 11.88% protocol 3. Variances in age, body-mass index, pneumonia diagnosis, do-not-resuscitate orders, Glasgow Coma Scale scores (≤ 14), and Acute Physiology and Chronic Health Evaluation II (APACHE) scores were notable across these protocols. Age, APACHE scores, and abnormal blood urea nitrogen levels (> 20 mg/dL) significantly correlated with outcomes-such as weaning, RCC survival, and 3-month survival. Elevated mean hemoglobin levels linked to increased weaning rates (p = 0.0065) and 3-month survival (p = 0.0102). Four adjusted models clarified the impact of rehabilitation protocols. Notably, the PR protocol 3 group exhibited significantly higher 3-month survival rates compared to protocol 1, with odds ratios (ORs) ranging from 3.87 to 3.97 across models. This association persisted when comparing with protocol 2, with ORs between 3.92 and 4.22.

CONCLUSION

Our study showed that distinct PR protocols significantly affected the outcomes of ventilator-dependent patients within RCCs. The study underlines the importance of tailored rehabilitation programs and identifies key clinical factors influencing patient outcomes. Recommendations advocate prospective studies with larger cohorts to comprehensively assess PR effects on RCC patients.

Differential effects of exercise intensity and tolerable duration on exercise-induced diaphragm and expiratory muscle fatigue

We investigated the effect of exercise intensity and tolerable duration on the development of exercise-induced diaphragm and expiratory muscle fatigue. Ten healthy adults (25 ± 5 yr; 2 females) cycled to intolerance on three separate occasions: 1) 5% below critical power ( 0.05). In conclusion, the magnitude of exercise-induced diaphragm fatigue was greater after longer-duration severe exercise than after shorter-duration severe and heavy exercise. By contrast, the magnitude of exercise-induced expiratory muscle fatigue was unaffected by exercise intensity and tolerable duration.NEW & NOTEWORTHY Exercise-induced respiratory muscle fatigue contributes to limiting exercise tolerance. Accordingly, better understanding the exercise conditions under which respiratory muscle fatigue occurs is warranted. Although heavy-intensity as well as short- and long-duration severe-intensity exercise performed to intolerance elicit diaphragm and expiratory muscle fatigue, we find, for the first time, that the relationship between exercise intensity, exercise duration, and the magnitude of exercise-induced fatigue is different for the diaphragm compared with the expiratory muscles.

The impact of posture correction bands on the respiratory function of healthy adults in their twenties: The difference between men and women

INTRODUCTION

Recently, interest in posture correction has increased in Korea owing to increased smartphone usage. However, there have been no studies to evaluate the impact of wearing a posture correction band with an abdominal band on breathing and respiratory function.

MATERIALS AND METHODS

A total of 32 healthy adults, consisting of 16 men (mean age: 23.19 ± 2.88) and 16 women (mean age: 19.69 ± 1.49) participated in this study. Pulmonary function tests were conducted before and after wearing posture correction bands.

RESULTS

In all the participants, forced vital capacity decreased significantly (P < .05) after wearing a posture correction band. The forced expiratory volume in 1 second and maximal inspiratory pressure decreased slightly (P > .05). The maximal expiratory pressure (MEP) and peak cough flow (PCF) increased slightly (P > .05). When respiratory functions were monitored separately in men and women after wearing a posture correction band, forced vital capacity and forced expiratory volume in 1 second were significantly reduced in men (P < .05). In women, MEP and PCF increased significantly (P < .05).

CONCLUSIONS

In this study, we confirmed that the posture correction band had an effect on respiratory function. Lung capacity was statistically significantly reduced but was not clinically significant. In addition, in the case of women, it was confirmed that the abdominal band improved the MEP and PCF.

Evolution and Functional Differentiation of the Diaphragm Muscle of Mammals

Symmorphosis is a concept of economy of biological design, whereby structural properties are matched to functional demands. According to symmorphosis, biological structures are never over designed to exceed functional demands. Based on this concept, the evolution of the diaphragm muscle (DIAm) in mammals is a tale of two structures, a membrane that separates and partitions the primitive coelomic cavity into separate abdominal and thoracic cavities and a muscle that serves as a pump to generate intra-abdominal (Pab ) and intrathoracic (Pth ) pressures. The DIAm partition evolved in reptiles from folds of the pleural and peritoneal membranes that was driven by the biological advantage of separating organs in the larger coelomic cavity into separate thoracic and abdominal cavities, especially with the evolution of aspiration breathing. The DIAm pump evolved from the advantage afforded by more effective generation of both a negative Pth for ventilation of the lungs and a positive Pab for venous return of blood to the heart and expulsive behaviors such as airway clearance, defecation, micturition, and child birth. © 2019 American Physiological Society. Compr Physiol 9:715-766, 2019.

Effect of Abdominal Binding on Diaphragmatic Neuromuscular Efficiency, Exertional Breathlessness, and Exercise Endurance in Chronic Obstructive Pulmonary Disease

We tested the hypothesis that abdominal binding (AB) would reduce breathlessness and improve exercise tolerance by enhancing neuromuscular efficiency of the diaphragm during exercise in adults with chronic obstructive pulmonary disease (COPD). In a randomized, controlled, crossover trial, 20 adults with COPD (mean ± SD FEV₁, 60 ± 16% predicted) completed a symptom-limited constant-load cycle endurance exercise test at 75% of their peak incremental power output with concomitant measures of the diaphragm electromyogram (EMGdi) and respiratory pressures without (CTRL) vs. with AB sufficient to increase end-expiratory gastric pressure (Pga,ee) by 6.7 ± 0.3 cmH₂O at rest. Compared to CTRL, AB enhanced diaphragmatic neuromuscular efficiency during exercise (p < 0.05), as evidenced by a 25% increase in the quotient of EMGdi to tidal transdiaphragmatic pressure swing. By contrast, AB had no demonstrable effect on exertional breathlessness and exercise tolerance; spirometry and plethysmography-derived pulmonary function test parameters at rest; and cardiac, metabolic, breathing pattern, inspiratory reserve volume and EMGdi responses during exercise (all p > 0.05 vs. CTRL). In conclusion, enhanced neuromuscular efficiency of the diaphragm during exercise with AB was not associated with relief of exertional breathlessness and improved exercise tolerance in adults with COPD. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT01852006.

Hydrogen Sulfide Alleviates Lipopolysaccharide-Induced Diaphragm Dysfunction in Rats by Reducing Apoptosis and Inflammation through ROS/MAPK and TLR4/NF-κB Signaling Pathways

Diaphragm dysfunction is an important clinical problem worldwide. Hydrogen sulfide (H₂S) is involved in many physiological and pathological processes in mammals. However, the effect and mechanism of H₂S in diaphragm dysfunction have not been fully elucidated. In this study, we detected that the level of H₂S was decreased in lipopolysaccharide- (LPS-) treated L6 cells. Treatment with H₂S increased the proliferation and viability of LPS-treated L6 cells. We found that H₂S decreased reactive oxygen species- (ROS-) induced apoptosis through the mitogen-activated protein kinase (MAPK) signaling pathway in LPS-treated L6 cells. Administration of H₂S alleviated LPS-induced inflammation by mediating the toll-like receptor-4 (TLR-4)/nuclear factor-kappa B (NF-κB) signaling pathway in L6 cells. Furthermore, H₂S improved diaphragmatic function and structure through the reduction of inflammation and apoptosis in the diaphragm of septic rats. In conclusion, these findings indicate that H₂S ameliorates LPS-induced diaphragm dysfunction in rats by reducing apoptosis and inflammation through ROS/MAPK and TLR4/NF-κB signaling pathways. Novel slow-releasing H₂S donors can be designed and applied for the treatment of diaphragm dysfunction.

Exercise-induced diaphragm fatigue in a Paralympic champion rower with spinal cord injury

The aim of this case report was to determine whether maximal upper body exercise was sufficient to induce diaphragm fatigue in a Paralympic champion adaptive rower with low-lesion spinal cord injury (SCI). An elite arms-only oarsman (age: 28 yr; stature: 1.89 m; and mass: 90.4 kg) with motor-complete SCI (T₁₂) performed a 1,000-m time trial on an adapted rowing ergometer. Exercise measurements comprised pulmonary ventilation and gas exchange, diaphragm EMG-derived indexes of neural respiratory drive, and intrathoracic pressure-derived indexes of respiratory mechanics. Diaphragm fatigue was assessed by measuring pre- to postexercise changes in the twitch transdiaphragmatic pressure (P_di,tw) response to anterolateral magnetic stimulation of the phrenic nerves. The time trial (248 ± 25 W, 3.9 min) elicited a peak O₂ uptake of 3.46 l/min and a peak pulmonary ventilation of 150 l/min (57% MVV). Breath-to-stroke ratio was 1:1 during the initial 400 m and 2:1 thereafter. The ratio of inspiratory transdiaphragmatic pressure to diaphragm EMG (neuromuscular efficiency) fell from rest to 600 m (16.0 vs. 3.0). Potentiated P_di,tw was substantially reduced (-33%) at 15-20 min postexercise, with only partial recovery (-12%) at 30-35 min. This is the first report of exercise-induced diaphragm fatigue in SCI. The decrease in diaphragm neuromuscular efficiency during exercise suggests that the fatigue was partly due to factors independent of ventilation (e.g., posture and locomotion). NEW & NOTEWORTHY This case report provides the first objective evidence of exercise-induced diaphragm fatigue in spinal cord injury (SCI) and, for that matter, in any population undertaking upper body exercise. Our data support the notion that high levels of exercise hyperpnea and factors other than ventilation (e.g., posture and locomotion) are responsible for the fatigue noted after upper body exercise. The findings extend our understanding of the limits of physiological function in SCI.