Impaired Respiratory Mechanics Research Articles

Impact of pectus excavatum deformity on the cardiopulmonary function: a literature review

BACKGROUND: Pectus excavatum deformity is the most common chest wall malformation. Currently, surgeons and researchers of this problem have no consensus on whether pectus excavatum is a purely aesthetic problem or whether pectus excavatum disturbs the function of the cardiopulmonary system. AIM: To analyze publications on the effect of pectus excavatum on the cardiorespiratory system and the functional features of the heart and lung after thoracoplasty in patients with pectus excavatum. MATERIALS AND METHODS: Data were searched in the scientific databases PubMed, Google Scholar, Cochrane Library, Crossref, and eLibrary without language limitation. In this article, the method of analysis and synthesis of information was used. Most of the studies included in the analysis were published in the last 20 years. RESULTS: In patients with pectus excavatum, severity of cardiorespiratory dysfunction depends on the degree of chest deformity. According to obtained data, the pulmonary function test in patients with pectus excavatum in the majority of cases revealed restrictive pattern (formed vital capacity 80% of the norm, with normal ratio of forced expiratory volume in 1 minute to forced lung capacity). In most cases, echocardiography showed compression of the right heart chambers. Comparative analysis of the pre- and postoperative study of cardiorespiratory system in most cases indicated improvement and adaptation of the cardiopulmonary system to stress after surgical intervention. CONCLUSIONS: Funnel chest is an aesthetic problem wherein a severe degree of deformity leads to impaired respiratory mechanics and dysfunction of the cardiovascular system. Surgical restoration of the volume of the retrosternal space allows improvement of the functional capabilities of the heart and lungs.

Individualized Positive End-expiratory Pressure Titration Strategies in Superobese Patients Undergoing Laparoscopic Surgery: Prospective and Nonrandomized Crossover Study.

Superobesity and laparoscopic surgery promote negative end-expiratory transpulmonary pressure that causes atelectasis formation and impaired respiratory mechanics. The authors hypothesized that end-expiratory transpulmonary pressure differs between fixed and individualized positive end-expiratory pressure (PEEP) strategies and mediates their effects on respiratory mechanics, end-expiratory lung volume, gas exchange, and hemodynamic parameters in superobese patients. In this prospective, nonrandomized crossover study including 40 superobese patients (body mass index 57.3 ± 6.4 kg/m2) undergoing laparoscopic bariatric surgery, PEEP was set according to (1) a fixed level of 8 cm H2O (PEEPEmpirical), (2) the highest respiratory system compliance (PEEPCompliance), or (3) an end-expiratory transpulmonary pressure targeting 0 cm H2O (PEEPTranspul) at different surgical positioning. The primary endpoint was end-expiratory transpulmonary pressure at different surgical positioning; secondary endpoints were respiratory mechanics, end-expiratory lung volume, gas exchange, and hemodynamic parameters. Individualized PEEPCompliance compared to fixed PEEPEmpirical resulted in higher PEEP (supine, 17.2 ± 2.4 vs. 8.0 ± 0.0 cm H2O; supine with pneumoperitoneum, 21.5 ± 2.5 vs. 8.0 ± 0.0 cm H2O; and beach chair with pneumoperitoneum; 15.8 ± 2.5 vs. 8.0 ± 0.0 cm H2O; P < 0.001 each) and less negative end-expiratory transpulmonary pressure (supine, -2.9 ± 2.0 vs. -10.6 ± 2.6 cm H2O; supine with pneumoperitoneum, -2.9 ± 2.0 vs. -14.1 ± 3.7 cm H2O; and beach chair with pneumoperitoneum, -2.8 ± 2.2 vs. -9.2 ± 3.7 cm H2O; P < 0.001 each). Titrated PEEP, end-expiratory transpulmonary pressure, and lung volume were lower with PEEPCompliance compared to PEEPTranspul (P < 0.001 each). Respiratory system and transpulmonary driving pressure and mechanical power normalized to respiratory system compliance were reduced using PEEPCompliance compared to PEEPTranspul. In superobese patients undergoing laparoscopic surgery, individualized PEEPCompliance may provide a feasible compromise regarding end-expiratory transpulmonary pressures compared to PEEPEmpirical and PEEPTranspul, because PEEPCompliance with slightly negative end-expiratory transpulmonary pressures improved respiratory mechanics, lung volumes, and oxygenation while preserving cardiac output.

Respiratory arrest after posterior fossa decompression in patients with Chiari malformations: An overview.

Chiari malformation type 1 (CM1) is a structural abnormality in the skull and cerebellum, causing cerebellar tonsils to shift downward. Decompression of the posterior fossa is a common surgical method to relieve symptoms and prevent neurological deterioration. After posterior fossa decompression (PFD), individuals with CM1 were more likely to have respiratory arrest. Here, we present, for the first time, a comprehensive overview of the potential risk factors and causes of respiratory arrest following PFD. A review of the literature highlighting the risk factors for postoperative respiratory arrest in CM1 patients was conducted in the databases of PubMed, Medline, and Google Scholar. Patients with syringomyelia and CM1 are at increased risk for respiratory arrest due to a number of factors, including impaired respiratory mechanics, central respiratory center dysfunction from edema or ischemia, intraoperative brain stem ischemia, and delayed gastric emptying from autonomic dysfunction. Occipitalization of the first cervical vertebra, basilar impression, and fusion of C2-C3 are all risk factors for respiratory arrest. Implications for CM1 patient care and prospects for further investigation of postoperative respiratory arrest's causes and risk factors were discussed.

Cardiorespiratory effects of different intraabdominal pressures in sheep: An experimental study.

Increased intraabdominal pressure (IAP) during laparoscopy can reduce venous return, but changes in respiratory system mechanics and their effect in left cardiac function are not well documented. This study evaluated the effects of different IAPs on respiratory mechanics and cardiac function in 10 healthy nonpregnant adult Santa Ines ewes randomly submitted to a crossover study using different IAPs: 0 mm Hg (G1), 10 mm Hg (G2), 12 mmHg (G3), and 15 mmHg (G4). Animals were anesthetized and mechanically ventilated (VT =15 ml/kg; positive end-expiratory pressure=3 cmH2 O; FiO2 =1.0). Pneumoperitoneum was induced by Hasson's trocar cannula. Variables were measured at INITIAL (IAP, 0 mmHg) and FINAL time points for each IAP after 1 h. At FINAL, driving airway pressure (ΔP,RS ), and percentage fraction of dead space (Vd/Vt) were higher in G3 and G4 than G1 (p=0.002, difference in means [MD] 4.60, 95% CI: 7.91-1.28, and p < 0.001, MD 5.4, 95% CI: 8.7-2.0; p=0.016, MD -9.5, 95% CI: -17.9 to -1.2; and p=0.027, MD -8.7, 95% CI: -17.1 to -0.4). The ejection fraction and fractional shortening were lower in G3 (p=0.039, MD -11.38, 95% CI: -0.07--22.68; p=0.015, MD -13.05, 95% CI: -1.74--24.36) and G4 (p=0.039, MD -9.94, 95% CI: -0.07 to -19.80; p=0.015, MD -11.43, 95%CI: -1.57 to -21.30, respectively) than G2. In G3, the maximum pulmonary flow velocity correlated negatively with ΔP,RS (r=-0.740; p=0.018), and Vd/Vt correlated positively with ΔP,RS (r=0.738, p=0.046). At IAP of 12 and 15 mm Hg impaired respiratory system mechanics, reduced left cardiac function and no change in maximum pulmonary artery flow velocity were detected. Therefore, respiratory mechanics should be monitored as an interplay to reduce left cardiac function.

Noninvasive Assessment of Neuromechanical and Neuroventilatory Coupling in COPD

This study explored the use of parasternal second intercostal space and lower intercostal space surface electromyogram (sEMG) and surface mechanomyogram (sMMG) recordings (sEMGpara and sMMGpara, and sEMGlic and sMMGlic, respectively) to assess neural respiratory drive (NRD), neuromechanical (NMC) and neuroventilatory (NVC) coupling, and mechanical efficiency (MEff) noninvasively in healthy subjects and chronic obstructive pulmonary disease (COPD) patients. sEMGpara, sMMGpara, sEMGlic, sMMGlic, mouth pressure (Pmo), and volume (Vi) were measured at rest, and during an inspiratory loading protocol, in 16 COPD patients (8 moderate and 8 severe) and 9 healthy subjects. Myographic signals were analyzed using fixed sample entropy and normalized to their largest values (fSEsEMGpara%max, fSEsMMGpara%max, fSEsEMGlic%max, and fSEsMMGlic%max). fSEsMMGpara%max, fSEsEMGpara%max, and fSEsEMGlic%max were significantly higher in COPD than in healthy participants at rest. Parasternal intercostal muscle NMC was significantly higher in healthy than in COPD participants at rest, but not during threshold loading. Pmo-derived NMC and MEff ratios were lower in severe patients than in mild patients or healthy subjects during threshold loading, but differences were not consistently significant. During resting breathing and threshold loading, Vi-derived NVC and MEff ratios were significantly lower in severe patients than in mild patients or healthy subjects. sMMG is a potential noninvasive alternative to sEMG for assessing NRD in COPD. The ratios of Pmo and Vi to sMMG and sEMG measurements provide wholly noninvasive NMC, NVC, and MEff indices that are sensitive to impaired respiratory mechanics in COPD and are therefore of potential value to assess disease severity in clinical practice.

Association Between Acute Kidney Injury During Invasive Mechanical Ventilation and ICU Outcomes and Respiratory System Mechanics.

OBJECTIVES:Compare ICU outcomes and respiratory system mechanics in patients with and without acute kidney injury during invasive mechanical ventilation.DESIGNS:Retrospective cohort study.SETTINGS:ICUs of the University of California, San Diego, from January 1, 2014, to November 30, 2016.PATIENTS:Five groups of patients were compared based on the need for invasive mechanical ventilation, presence or absence of acute kidney injury per the Kidney Disease: Improving Global Outcomes criteria, and the temporal relationship between the development of acute kidney injury and initiation of invasive mechanical ventilation.INTERVENTIONS:None.MEASUREMENTS AND MAIN RESULTS:A total of 9,704 patients were included and 4,484 (46%) required invasive mechanical ventilation; 2,009 patients (45%) had acute kidney injury while being treated with invasive mechanical ventilation, and the mortality rate for these patients was 22.4% compared with 5% in those treated with invasive mechanical ventilation without acute kidney injury (p < 0.01). Adjusted hazard of mortality accounting for baseline disease severity was 1.58 (95% CI, 1.22–2.03; p < 0.001]. Patients with acute kidney injury during invasive mechanical ventilation had a significant increase in total ventilator days and length of ICU stay with the same comparison (both p < 0.01). Acute kidney injury during mechanical ventilation was also associated with significantly higher plateau pressures, lower respiratory system compliance, and higher driving pressures (all p < 0.01). These differences remained significant in patients with net negative cumulative fluid balance.CONCLUSIONS:Acute kidney injury during invasive mechanical ventilation is associated with increased ICU mortality, increased ventilator days, increased length of ICU stay, and impaired respiratory system mechanics. These results emphasize the need for investigations of ventilatory strategies in the setting of acute kidney injury, as well as mechanistic studies of crosstalk between the lung and kidney in the critically ill.

Exercise invasive hemodynamics in adults post-Fontan: A novel tool in understanding functional limitation and liver disease.

Functional impairment is essentially universal among adults post-Fontan palliation. Cardiac catheterization is frequently performed in patients post-Fontan but normal resting Fontan and ventricular filling pressures are commonly recorded even in highly symptomatic individuals. Ascertaining the etiology of exertional symptoms in these individuals is further complicated by the prevalence of co-existent sarcopenia, abnormal skeletal muscle function, impaired respiratory mechanics, and deconditioning. Exercise right heart catheterization is increasingly used in acquired heart disease but the diagnostic yield of exercise at the time of cardiac catheterization in Fontan patients remains largely unknown. We report herein exercise catheterization findings in 4 consecutive adults post-Fontan referred to our laboratory. We believe this novel series illustrates several potential roles for exercise during catheterization of adults post-Fontan, with each patient having a unique constellation of hemodynamic findings to explain their clinical presentation and tailor their management.

Complications of Endobronchial Valve Placement for Bronchoscopic Lung Volume Reduction: Insights From the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE).

Patients with advanced emphysema experience breathlessness due to impaired respiratory mechanics and diaphragm dysfunction. Bronchoscopic lung volume reduction (BLVR) is a minimally invasive bronchoscopic procedure done to reduce hyperinflation and air trapping, promoting atelectasis in the targeted lobe and allowing improved respiratory mechanics. Real-world data on safety and complications outside of clinical trials of BLVR are limited. We queried the US Food and Drug Administrations (FDA) Manufacturers and User Device Experience database from May 2019 to June 2020 for reports involving BLVR with endobronchial valve (EBV) placement. Events were reviewed for data analysis. We identified 124 cases of complications during BLVR with EBV implantation. The most-reported complication was pneumothorax (110/124, 89%), all of which required chest tube placement. A total of 54 of these cases (54/110, 49%) were complicated by persistent air leak requiring additional interventions. Repeat bronchoscopy was needed to remove the valves in 28 patients, 12 were discharged with a Heimlich valve, and 10 had an additional pleural catheter placed. The other complications of BLVR with EBV placement included respiratory failure (6/124, 5%), pneumonia (4/124, 3%), hemoptysis (2/124, 1.6%), valve migration (1/124, 1%), and pleural effusion (1/124, 1%). A total of 14 deaths were reported during that year. Pneumothorax is the most-reported complication for BLVR with EBV placement, and in 65% of cases, pneumothorax is managed without removing valves. Importantly, 14 deaths were reported during that timeframe. Further studies are needed to estimate the true magnitude of the complications associated with BLVR.

Diagnostic Accuracy of Combined Mallampati and Wilson Score to Predict Difficult Intubation in Obese Patients: A Descriptive Cross-sectional Study

BackgroundAirway protection during anesthesia is often the primary concern of anesthetists when working with obese patients and always is a difficult task due to increased exposure to harmful effects of apnea, hypoxia, and impaired respiratory mechanics.ObjectivesThe primary goal of this research was to determine the diagnostic accuracy of combined Mallampati and Wilson score in detecting difficult intubation in obese patients undergoing surgery by taking the Cormack-Lehane grading on direct laryngoscopy and intubation as the gold standard.MethodsThis descriptive cross-sectional study was done in 300 obese patients with BMI > 29.9 kg/m2. Modified Mallampati and Wilson score was recorded preoperatively for each patient in the sitting position by the primary investigator. Endotracheal intubation grades were also recorded, and grades IIb, III, and IV were regarded as difficult intubation according to the Cormack-Lehane intubation classification.ResultsThe mean age was 46.76 ± 15.57 years. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the combined Mallampati and Wilson score for detecting difficult laryngoscopy and difficult intubation were 75.0, 98.8, 92.9, 95.0, and 94.6%, respectively.ConclusionsCombined Mallampatti and Wilson score is highly accurate in the initial diagnostic workup of obese patients at risk of difficult intubation. It is easy to calculate and lower the risk of intubation-related complications and failure.

Obesity and infectious diseases: pathophysiology and epidemiology of a double pandemic condition.

The current pandemic due to widespread SARS-CoV-19 infection has again highlighted the role of obesity, whose global prevalence increased up to 13%, as a risk factor for both susceptibility to infections and the occurrence of a more severe disease course. To date, this association has not been sufficiently explored. Obesity-related susceptibility to infectious diseases is mostly thought to be due to an impairment of both innate and adaptive immune responses and vitamin D deficiency. Several cofactors can indirectly favour the onset and/or worsening of infectious diseases, such as impairment of respiratory mechanics, skin and subcutaneous tissue homoeostasis, obesity-related comorbidities and inappropriate antimicrobial therapy. Subjects with obesity have a higher incidence of cutaneous infections, probably due to changes in skin barrier functions and wound healing. Excess weight is also associated with an increased risk of urinary tract infection and its recurrence, as well as with a higher prevalence of both lower and higher respiratory tract infections. Moreover, patients with obesity appear to have an increased risk of surgical site infections when undergoing general, orthopaedic, gynaecological, and bariatric surgery. Data concerning the different infectious diseases related to obesity are rather limited since anthropometric parameters are usually poorly recorded. Furthermore, specific therapeutic protocols in subjects with obesity are lacking, especially regarding antibiotic therapy and further supplements. This review summarizes etiopathogenetic and epidemiological evidence and highlights areas of uncertainty in the field of infectious diseases and obesity, which require further research. It is important to raise public awareness of this additional risk related to obesity and to raise awareness among the scientific community to develop specific clinical protocols for subjects with obesity.

COVID-19 pneumonia: pathophysiology and management.

Coronavirus disease 2019 (COVID-19) pneumonia is an evolving disease. We will focus on the development of its pathophysiologic characteristics over time, and how these time-related changes determine modifications in treatment. In the emergency department: the peculiar characteristic is the coexistence, in a significant fraction of patients, of severe hypoxaemia, near-normal lung computed tomography imaging, lung gas volume and respiratory mechanics. Despite high respiratory drive, dyspnoea and respiratory rate are often normal. The underlying mechanism is primarily altered lung perfusion. The anatomical prerequisites for PEEP (positive end-expiratory pressure) to work (lung oedema, atelectasis, and therefore recruitability) are lacking. In the high-dependency unit: the disease starts to worsen either because of its natural evolution or additional patient self-inflicted lung injury (P-SILI). Oedema and atelectasis may develop, increasing recruitability. Noninvasive supports are indicated if they result in a reversal of hypoxaemia and a decreased inspiratory effort. Otherwise, mechanical ventilation should be considered to avert P-SILI. In the intensive care unit: the primary characteristic of the advance of unresolved COVID-19 disease is a progressive shift from oedema or atelectasis to less reversible structural lung alterations to lung fibrosis. These later characteristics are associated with notable impairment of respiratory mechanics, increased arterial carbon dioxide tension (PaCO2), decreased recruitability and lack of response to PEEP and prone positioning.

Impact of Oxygen Concentration Delivered via Nasal Cannula on Different Lung Conditions: A Bench Study.

Background: Measuring the fraction of inspired oxygen (FiO2) is challenging in spontaneously breathing patients with impaired respiratory mechanics during low-flow nasal cannula. Our study investigates the FiO2 with varied tidal volume (VT) and respiratory rate (RR) among different lung mechanics and provides equations to estimate the FiO2. Methods: Two training and test lungs were used in this study, and the three lung mechanics (normal (R5/C60), restrictive (R20/C80), obstructive (R5/C40)) were designed. Spontaneous breathing with VT (300, 500, and 700 mL) and RR (10, 20, and 30 breaths/min) was simulated. The flow rate of the nasal cannula was set to 1, 3, and 5 L per minute (LPM), and the FiO2 was measured at the carina. Results: The lowest and highest FiO2 were evident during high (700 mL) and low VT (300 mL), respectively, among normal, restrictive, and obstructive lung models. As RR increases, this decreases the FiO2. However, we found that VT and oxygen flow rate are the principal factors influencing measured FiO2 by multiple linear regression analysis. Conclusions: Our data suggest that the actual FiO2 is never as high in spontaneously breathing patients as that estimated. VT and oxygen flow rate had a substantial impact on the FiO2.

Effect of Bronchoscopic Lung Volume Reduction in Advanced Emphysema on Energy Balance Regulation

Background: Hypermetabolism and muscle wasting frequently occur in patients with severe emphysema. Improving respiratory mechanics by bronchoscopic lung volume reduction (BLVR) might contribute to muscle maintenance by decreasing energy requirements and alleviating eating-related dyspnoea. Objective: The goal was to assess the impact of BLVR on energy balance regulation. Design: Twenty emphysematous subjects participated in a controlled clinical experiment before and 6 months after BLVR. Energy requirements were assessed: basal metabolic rate (BMR) by ventilated hood, total daily energy expenditure (TDEE) by doubly labelled water, whole body fat-free mass (FFM) by deuterium dilution, and physical activity by accelerometry. Oxygen saturation, breathing rate, and heart rate were monitored before, during, and after a standardized meal via pulse oximetry and dyspnoea was rated. Results: Sixteen patients completed follow-up, and among those, 10 patients exceeded the minimal clinically important difference of residual volume (RV) reduction. RV was reduced with median (range) 1,285 mL (−2,430, −540). Before BLVR, 90% of patients was FFM-depleted despite a normal BMI (24.3 ± 4.3 kg/m²). BMR was elevated by 130%. TDEE/BMR was 1.4 ± 0.2 despite a very low median (range) daily step count of 2,188 (739, 7,110). Following BLVR, the components of energy metabolism did not change significantly after intervention compared to before intervention, but BLVR treatment decreased meal-related dyspnoea (4.1 vs. 1.7, p = 0.019). Conclusions: Impaired respiratory mechanics in hyperinflated emphysematous patients did not explain hypermetabolism. Clinical Trial Registry Number: NCT02500004 at www.clinicaltrial.gov.

Acute effects of noninvasive ventilation on sleep physiology in patients with moderate to severe stable chronic obstructive pulmonary disease: a pilot study

Objective/backgroundChanges in sleep architecture in patients with Chronic Obstructive Pulmonary Disease (COPD) can be explained by a combination of physiological changes in breathing during sleep, with impairment of respiratory mechanics and reduction of arterial oxygenation. This study aimed to evaluate the acute effects of noninvasive ventilation (NIV) – compared to spontaneous breathing – on sleep latency and stages, and on the occurrence of sleep-related respiratory events, nocturnal hypoxemia, and changes in heart rate (HR) in patients with moderate to severe stable COPD. Patients/methodsPatients completed two polysomnography (PSG) studies: one during spontaneous breathing and one while receiving NIV in bilevel mode and with backup respiratory rate (RR.) setting. Sleepware G3 software was used for the analysis of PSG and pressure, volume, and ventilator flow curves × time. ResultsParticipants were 10 female patients with a mean age of 68.1 ± 10.2 years. NIV during sleep decreased sleep onset latency (17 ± 18.8 min vs 46.8 ± 39.5 min; p = 0.02), increased REM sleep time (41.2 ± 24.7 min vs 19.7 ± 21.7 min; p = 0.03), and decreased the obstructive apnea index (OAI) (0 vs 8.7 ± 18.8; p = 0.01). Lower mean HR (66.6 ± 4.1 bpm vs 70.6 ± 5.9 bpm; p = 0.03) and lower maximum HR (84.1 ± 7.3 bpm vs 91.6 ± 7.8 bpm; p = 0.03) were observed in PSG with NIV. ConclusionsThe use of NIV in patients with moderate to severe stable COPD while they were sleeping increased REM sleep time and decreased sleep onset latency, the number of obstructive respiratory events, and the mean and maximum HR.

Sleep quality and architecture in COPD: the relationship with lung function abnormalities.

ABSTRACTObjective:Impaired respiratory mechanics and gas exchange may contribute to sleep disturbance in patients with COPD. We aimed to assess putative associations of different domains of lung function (airflow limitation, lung volumes, and gas exchange efficiency) with polysomnography (PSG)-derived parameters of sleep quality and architecture in COPD. Methods:We retrospectively assessed data from COPD 181 patients ≥ 40 years of age who underwent spirometry, plethysmography, and overnight PSG. Univariate and multivariate linear regression models predicted sleep efficiency (total sleep time/total recording time) and other PSG-derived parameters that reflect sleep quality. Results:The severity of COPD was widely distributed in the sample (post-bronchodilator FEV1 ranging from 25% to 128% of predicted): mild COPD (40.3%), moderate COPD (43.1%), and severe-very severe COPD (16.6%). PSG unveiled a high proportion of obstructive sleep apnea (64.1%) and significant nocturnal desaturation (mean pulse oximetry nadir = 82.2% ± 6.9%). After controlling for age, sex, BMI, apnea-hypopnea index, nocturnal desaturation, comorbidities, and psychotropic drug prescription, FEV1/FVC was associated with sleep efficiency (β = 25.366; R2 = 14%; p < 0.001), whereas DLCO predicted sleep onset latency (β = −0.314; R2 = 13%; p < 0.001) and rapid eye movement sleep time/total sleep time in % (β = 0.085; R2 = 15%; p = 0.001). Conclusions:Pulmonary function variables reflecting severity of airflow and gas exchange impairment, adjusted for some potential confounders, were weakly related to PSG outcomes in COPD patients. The direct contribution of the pathophysiological hallmarks of COPD to objectively measured parameters of sleep quality seems to be less important than it was previously assumed.

Impaired respiratory mechanics and the role of IL-6 in COPD investigated by end-inflation occlusion method

Impaired respiratory mechanics and the role of IL-6 in COPD investigated by end-inflation occlusion method

Robotic diaphragmatic plication for eventration: A retrospective analysis of efficacy, safety, and feasibility.

Eventration of the diaphragm results in impaired respiratory mechanics, which leads to symptoms of dyspnea. Robotic diaphragmatic plication is a recently reported technique that has had good immediate outcomes. The aim of this study was to describe our transthoracic and transabdominal plication techniques and to analyze the safety, efficacy, and feasibility of robotic diaphragmatic plication in an Indian setting. This retrospective study was conducted at a large tertiary care center in a dedicated thoracic surgery unit. To measure the efficacy of plication, we administered a pulmonary function test to each patient at baseline and 6 months postoperatively and then compared the results. Eighteen patients underwent robotic diaphragmatic plication during the study period. Of these 18 patients, 12 underwent surgery via a transabdominal approach, and 6 underwent surgery via a transthoracic approach. Surgery was completed robotically in 17 patients. The comparison of the preoperative and postoperative pulmonary function test results showed that the mean ± SD increase in forced expiratory volume in 1 second (FEV1 ) was 19.9 ± 22.0% (P = .002) and the mean increase in FEV1 /forced vital capacity was 5.7 ± 2.5 % (P = .225), indicating a significant improvement in FEV1 after surgery. Robotic diaphragmatic plication can be performed transthoracically or transabdominally with good surgical outcomes. It is safe, effective, and feasible.

A possible association between fructose consumption and pulmonary emphysema

Chronic Obstructive Pulmonary Disease (COPD) is a syndrome that comprises several distinct and overlapping phenotypes. In addition to persistent airflow limitation and respiratory symptoms, COPD is also characterized by chronic systemic inflammation. Epidemiological studies have shown that dietary fibers, fruits and vegetables intake protects against the COPD development, while fructose-loading is associated with increased risk of asthma and chronic bronchitis. Since dietary factors might affect susceptibility to COPD by modulating oxidative stress and inflammatory responses, we evaluated how fructose feeding might affect the smoking-induced emphysema in mice. We found that chronic fructose intake induced destruction and remodeling of lung parenchyma and impairment of respiratory mechanics, which are associated with distinctive cytokine profiles in bronchoalveolar lavage fluid, blood plasma and skeletal muscle. The combined effects of chronic fructose intake and cigarette smoking on destruction of lung parenchyma are more pronounced than the effects of either alone. Excessive intake of fructose might directly cause pulmonary emphysema in mice rather than just altering its natural history by facilitating the installation of a low-grade systemic inflammatory milieu.

Utility of the six-minute walk test in patients with idiopathic pulmonary fibrosis

The six-minute walk test (6MWT) is a simple test that is widely used to assess functional exercise capacity in patients with idiopathic pulmonary fibrosis (IPF). Patients with IPF have reduced exercise capacity due to a number of factors, such as impaired respiratory mechanics and circulatory problems. As a self-paced and usually submaximal exercise test, the 6MWT reflects the exercise level of everyday activities. Variables measured during the 6MWT, such as six-minute walk distance (6MWD) and desaturation, are strong predictors of mortality in patients with IPF. However, the results of a 6MWT are affected by numerous factors, including age, body size, comorbidities and the use of supplemental oxygen during the test, and these need to be borne in mind when interpreting the results of individual and serial tests. Clinical studies, including trials of potential therapies for IPF, have differed in the methodology used to implement the 6MWT, hindering the comparison of results across studies. In this review, I describe the utility of the 6MWT in patients with IPF and provide recommendations for standardisation of the test for use both in clinical practice and research. A brief video

Inspiratory muscle training improves exercise capacity with thoracic load carriage.

Thoracic load carriage (LC) exercise impairs exercise performance compared to unloaded exercise, partially due to impaired respiratory mechanics. We investigated the effects of LC on exercise and diaphragmatic fatigue in a constant‐load exercise task; and whether inspiratory muscle training (IMT) improved exercise capacity and diaphragmatic fatigue with LC. Twelve recreationally active males completed three separate running trials to exhaustion (T lim) at a fixed speed eliciting 70% of their V˙O2max. The first two trials were completed either unloaded (UL) or while carrying a 10 kg backpack (LC). Subjects then completed 6 weeks of either true IMT or placebo‐IMT. Posttraining, subjects completed an additional LC trial identical to the pretraining LC trial. Exercise metabolic and ventilatory measures were recorded. Diaphragm fatigue was assessed as the difference between preexercise and postexercise twitch diaphragmatic pressure (P di, tw), assessed by bilateral stimulation of the phrenic nerve with esophageal balloon‐tipped catheters measuring intrathoracic pressures. T lim was significantly shorter (P < 0.001) with LC compared with UL by 42.9 (29.1)% (1626.5 (866.7) sec and 2311.6 (1246.5) sec, respectively). The change in P di, tw from pre‐ to postexercise was significantly greater (P = 0.001) in LC (−13.9 (5.3)%) compared with UL (3.8 (6.5)%). Six weeks of IMT significantly improved T lim compared to pretraining (P = 0.029, %Δ +29.3 (15.7)% IMT, −8.8 (27.2)% Placebo), but did not alter the magnitude of diaphragmatic fatigue following a run to exhaustion (P > 0.05). Minute ventilation and breathing mechanics were unchanged post‐IMT (P > 0.05). Six weeks of flow‐resistive IMT improved exercise capacity, but did not mitigate diaphragmatic fatigue following submaximal, constant‐load running to volitional exhaustion with LC.