Changes In Lung Volume Research Articles

Matrix Metalloproteinases in Pathogenesis of Ventilation Disorders of the Respiratory System in Patients with Chronic Pulmonary Tuberculosis

The imbalance in matrix metalloproteinase (MMP)/inhibitors system leads to degradation of extracellular matrix of connective tissue and pathological remodeling forming the morphological basis for respiratory dysfunction.The objective: to study the relationship between parameters of MMP/inhibitors system in blood and parameters of ventilation and gas exchange disorders in patients with chronic pulmonary tuberculosis (PTB).Subjects and Methods. Patients with the verified diagnosis of tuberculoma (n = 45) and fibrous-cavernous pulmonary tuberculosis (n = 85) were examined. All patients underwent computed tomography of the chest and assessment of respiratory function. Serum concentrations of MMP-1, -3, -8, -9 and their inhibitors TIMP-1 and α2-macroglobulin (MG) were tested by ELISA (R&D Systems, Minneapolis, MN, USA). Statistica 7.0 and an ANCOVA model were used for statistical analysis which considered the diagnosis and smoking status as factors, and the respiratory function parameters were considered as covariates.Results. In pulmonary tuberculosis patients, the concentrations of MMP-9 and MMP-8 in the blood correlated with extension of lung parenchyma lesions when compared to tuberculomas and fibro-cavernous tuberculosis, MMP-9 and TIMP-1 with changes in lung volumes (R2 = 0.60 and 0.80; p = 0.001), and MMP-8 correlated with functional disorders of gas exchange (R2 = 0.60 and 0.80; p = 0.001). Changes in MMP-1, MMP-3, and α2-MG (R2 = 0.60 and 0.80; p = 0.45) did not correlate with extension of lung parenchymal lesions and decreased lung function.

A new approach for the detection of obesity-related airway obstruction in lung-healthy individuals

BackgroundSubjects with obesity show an increased prevalence of airway obstruction but it is not clear in each case whether this reflects genuine lung disease. Via intentional increase in end-expiratory lung volume we studied the detection of obesity-induced airway obstruction in lung-healthy obese subjects. MethodsThe primary study population comprised 66 lung-healthy obese subjects and 23 normal weight subjects. Measurements were performed in a body plethysmograph allowing for recording and quantification of breathing loops in terms of specific airway resistance at both normal and intentionally elevated end-expiratory lung volume. The change in volume was documented by a shutter maneuver. ResultsThe voluntary increase of lung volume led to a significant reduction of expiratory airway resistance in 11 of the 66 obese subjects. This reduction could be quantified by a change of total expiratory resistance (sRtEX) of >1 kPa*s but was also clearly visible in the breathing loops. sRtEX showed the largest change among all resistance parameters. The loops of normal weight subjects remained virtually unaffected by the change in lung volume. Moreover, those of 5 obese patients with COPD who were measured for comparison partially showed a reduction of resistance but airway obstruction remained. ConclusionThe proposed breathing maneuver was simple to perform and allowed for a quantitative and qualitative detection of obesity-induced airway obstruction. This might help in reducing the likelihood of misdiagnosis and overtreatment of obese patients.

Postural changes in lung volumes in patients with heart failure and Cheyne-Stokes respiration: Relationship with sleep apnea severity

Background and aimIt has been proposed that the increased severity of sleep apnea frequently observed in heart failure (HF) patients with Cheyne-Stokes respiration (CSR) when sleeping in the supine compared to the lateral position, may be caused by the concomitant reduction in functional residual capacity (FRC). We assessed positional changes in FRC in patients with CSR and investigated the relationship between these changes in the laboratory and corresponding changes in CSR severity during sleep. MethodsAfter a diagnostic polysomnography, 18 HF patients with dominant CSR and an apnea-hypopnea index (AHI)≥15 events/h underwent a standard pulmonary function test in the sitting position. Measurements were repeated in the supine, left lateral and right lateral. The latter two measurements were averaged to obtain a single lateral measurement. ResultsThe FRC in the seated position was 3.0 ± 0.5 L (85 ± 13% of predicted), decreased to 2.3 ± 0.3 L (−21 ± 8%, p < 0.0001) in the supine position, and increased to 2.8 ± 0.4 L (+21 ± 12%, p < 0.0001) from the supine to the lateral position (−5±8% vs seated, p = 0.013). During sleep, the AHI and the apnea index (AI) decreased from 47 ± 15 events/h to 26 ± 12 events/h (−46 ± 20%, p < 0.0001) and from 29 ± 21 events/h to 12 ± 10 events/h (−61 ± 40%, p < 0.001) from the supine to the lateral position. Changes in the AI were significantly correlated with corresponding changes in FRC (ρ = −0.55, p = 0.032). ConclusionIn patients with HF and CSR, lying in the supine position causes a significant reduction in FRC in the context of a chronically reduced FRC. The negative correlation between postural changes in FRC and AI supports the hypothesis that the reduction in lung gas stores in the supine position may promote/exacerbate respiratory control instability.

Transition from BOS to RAS impairs prognosis after lung transplantation—CLAD subtype analysis by CT volumetry

BackgroundChronic lung allograft dysfunction (CLAD), subclassified into bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS), limits survival after lung transplantation. Information concerning transition from BOS to RAS is limited. We aimed to characterize the lung volume change after BOS diagnosis by computed tomography (CT) volumetry and to determine the incidence, risk factors and clinical significance of BOS to RAS transition.MethodsCT volumetry measurements were performed from 63 patients with CLAD initially classified as BOS by CT volumetry. BOS patients with lung volume remaining >85% of baseline were classified as persistent BOS, whereas BOS patients whose lung volume permanently decreased to ≤85% of baseline were classified as BOS to RAS transition.ResultsDuring follow-up (median 9.8 years) eight patients (12.7%) were classified as BOS to RAS transition, which decreased recipient (p = 0.004) and graft survival (p = 0.020) in comparison to patients with persistent BOS. Opacities on chest imaging preceded BOS to RAS transition in 88% of patients. Opacities on chest imaging at BOS diagnosis and early CLAD diagnosis after transplantation were risk factors for transition.ConclusionBased on lung volume decrease measured by CT volumetry, a small proportion of BOS patients transitioned to RAS which had an adverse effect on recipient and graft survival.

Accurate measures of changes in regional lung air volumes from chest x-rays of small animals

Objective. To develop a robust technique for calculating regional volume changes within the lung from x-ray radiograph sequences captured during ventilation, without the use of computed tomography (CT). Approach. This technique is based on the change in transmitted x-ray intensity that occurs for each lung region as air displaces the attenuating lung tissue. Main results. Lung air volumes calculated from x-ray intensity changes showed a strong correlation (R 2 = 0.98) against the true volumes, measured from high-resolution CT. This correlation enables us to accurately convert projected intensity data into relative changes in lung air volume. We have applied this technique to measure changes in regional lung volumes from x-ray image sequences of mechanically ventilated, recently-deceased newborn rabbits, without the use of CT. Significance. This method is suitable for biomedical research studies,enabling quantitative regional measurement of relative lung air volumes at high temporal resolution, and shows great potential for future clinical application.

Low-cost structured light imaging of regional volume changes for use in assessing mechanical ventilation

BackgroundOptimal setting of mechanical ventilators is critical for improving outcomes. Accurate, predictive lung mechanics models are effective in optimizing MV settings, but only at a global level as they cannot estimate regional lung volume ventilation to assess the potential of local distension or under-ventilation. This study presents a low-cost structured light system for non-contact high resolution chest motion measurement to estimate regional lung volume changes. MethodsThe system consists of a structured light projector and two cameras. A new pattern is designed to extract motion from sub-regions of the chest surface, and an efficient feature is proposed to provide a fast and accurate correspondence matching between two views. Reconstruction of 3D surface points is based on the matched points and stereo method. Asymmetric distribution of tidal volume into left and right lungs is estimated based on reconstructed regional chest expansion. A proof-of-concept experiment using a dummy model and two test lungs connected to a ventilator to provide differential chest expansion is conducted under tidal volumes of 400 ml, 500 ml and 600 ml, with results compared to the widely-used SURF and ORB methods. ResultsCompared to the SURF and ORB methods, the proposed method is more computationally efficient with ∼40% less computational time cost, and higher accuracy for dense point correspondence. Finally, the proposed method estimated the region lung volumes with the maximum error of 8 ml under 600 ml tidal volume, indicating a good accuracy. ConclusionsSurface reconstruction results in a proof-of-concept experiment with differential chest expansion show good performance for the proposed pattern and method in extracting the key information for regional chest expansion. The proposed method is generalizable, with potential for use in other applications.

Positive- and Negative-Pressure Ventilation Characterized by Local and Global Pulmonary Mechanics.

Rationale: There is continued debate regarding the equivalency of positive-pressure ventilation (PPV) and negative-pressure ventilation (NPV). Resolving this question is important because of the different practical ramifications of the two paradigms. Objectives: We sought to investigate the parallel between PPV and NPV and determine whether or not these two paradigms cause identical ventilation profiles by analyzing the local strain mechanics when the global tidal volume (Vt) and inflation pressure was matched. Methods: A custom-designed electromechanical apparatus was used to impose equal global loads and displacements on the same ex vivo healthy porcine lung using PPV and NPV. High-speed high-resolution cameras recorded local lung surface deformations and strains in real time, and differences between PPV and NPV global energetics, viscoelasticity, as well as local tissue distortion were assessed. Measurements and Main Results: During initial inflation, NPV exhibited significantly more bulk pressure-volume compliance than PPV, suggestive of earlier lung recruitment. NPV settings also showed reduced relaxation, hysteresis, and energy loss compared with PPV. Local strain trends were also decreased in NPV, with reduced tissue distortion trends compared with PPV, as revealed through analysis of tissue anisotropy. Conclusions: Apparently, contradictory previous studies are not mutually exclusive. Equivalent changes in transpulmonary pressures in PPV and NPV lead to the same changes in lung volume and pressures, yet local tissue strains differ between PPV and NPV. Although limited to healthy specimens and ex vivo experiments in the absence of a chest cavity, these results may explain previous reports of better oxygenation and less lung injury in NPV.

Statistical evaluation of the effectiveness of dual amplitude-gated stereotactic body radiotherapy using fiducial markers and lung volume.

The low tracking accuracy of lung stereotactic body radiotherapy (SBRT) risks reduced treatment efficacy. We used four-dimensional computed tomography (4DCT) images to determine the correlation between changes in fiducial marker positions and lung volume for lung tumors, and we evaluated the effectiveness of the combined use of these images in lung SBRT. Data of 30 patients who underwent fiducial marker placement were retrospectively analyzed. We calculated the motion amplitudes of the center of gravity coordinates of the lung tumor and fiducial markers in each phase and the ipsilateral, contralateral, and bilateral lung volumes using 4DCT. Moreover, we calculated the cross-correlation coefficient between the fiducial marker position and the lung volume changes waveform for the motion amplitude waveform of the lung tumor over three gating windows (all phases, ≤2 mm3, and ≤3mm3). Compared with the lung volume, approximately 30% of the fiducial markers demonstrated a low correlation with the lung tumor. In the ≤2mm3 and ≤3mm3 gating windows, the cross-correlation coefficients between the lung tumor and the optimal marker (r>0.9: 83% and 86%) were significantly different for all fiducial markers (r>0.9: 39%, 53%) and the ipsilateral (r>0.9: 35% and 40%), contralateral (r>0.9: 44% and 41%), and bilateral (r>0.9: 39% and 45%) lung volumes. Some of the fiducial markers showed a low correlation with the lung tumor. This study indicated that the combined use of lung volume monitoring can improve tracking accuracy.

Changes in lung volume estimated by electrical impedance tomography during apnea and high-flow nasal oxygenation: A single-center randomized controlled trial.

BackgroundPrevious studies concerning humidified, heated high-flow nasal oxygen delivered in spontaneously breathing patients postulated an increase in functional residual capacity as one of its physiological effects. It is unclear wheter this is also true for patients under general anesthesia.MethodologyThe sincle-center noninferiority trial was registered at ClinicalTrials.gov (NCT NCT03478774). This secondary outcome analysis shows estimated differences in lung volume changes using electrical impedance tomography between different flow rates of 100% oxygen in apneic, anesthetized and paralyzed adults prior to intubation. One hundred and twenty five patients were randomized to five groups with different flow rates of 100% oxygen: i) minimal-flow: 0.25 l.min-1 via endotracheal tube; ii) low-flow: 2 l.min-1 + continuous jaw thrust; iii) medium-flow: 10 l.min-1 + continuous jaw thrust; iv) high-flow: 70l.min-1 + continuous jaw thrust; and v) control: 70 l.min-1 + continuous video-laryngoscopy. After standardized anesthesia induction with non-depolarizing neuromuscular blockade, the 15-minute apnea period and oxygen delivery was started according to the randomized flow rate. Continuous electrical impedance tomography measurements were performed during the 15-minute apnea period. Total change in lung impedance (an estimate of changes in lung volume) over the 15-minute apnea period and times to 25%, 50% and 75% of total impedance change were calculated.ResultsOne hundred and twenty five patients completed the original study. Six patients did not complete the 15-minute apnea period. Due to maloperation, malfunction and artefacts additional 54 measurements had to be excluded, resulting in 65 patients included into this secondary outcome analysis. We found no differences between groups with respect to decrease in lung impedance or curve progression over the observation period.ConclusionsDifferent flow rates of humidified 100% oxygen during apnea result in comparable decreases in lung volumes. The demonstrated increase in functional residual capacity during spontaneous breathing with high-flow nasal oxygenation could not be replicated during apnea under general anesthesia with neuromuscular blockade.

Quantitative lung ultrasound detects dynamic changes in lung recruitment in the preterm lamb

BackgroundLung ultrasound (LUS) may not detect small, dynamic changes in lung volume. Mean greyscale measurement using computer-assisted image analysis (Q-LUSMGV) may improve the precision of these measurements.MethodsPreterm lambs (n = 40) underwent LUS of the dependent or non-dependent lung during static pressure–volume curve mapping. Total and regional lung volumes were determined using the super-syringe technique and electrical impedance tomography. Q-LUSMGV and gold standard measurements of lung volume were compared in 520 images.ResultsDependent Q-LUSMGV moderately correlated with total lung volume (rho = 0.60, 95% CI 0.51–0.67) and fairly with right whole (rho = 0.39, 0.27–0.49), central (rho = 0.38, 0.27–0.48), ventral (rho = 0.41, 0.31–0.51) and dorsal regional lung volumes (rho = 0.32, 0.21–0.43). Non-dependent Q-LUSMGV moderately correlated with total lung volume (rho = 0.57, 0.48–0.65) and fairly with right whole (rho = 0.43, 0.32–0.52), central (rho = 0.46, 0.35–0.55), ventral (rho = 0.36, 0.25–0.47) and dorsal lung volumes (rho = 0.36, 0.25–0.47). All correlation coefficients were statistically significant. Distinct inflation and deflation limbs, and sonographic pulmonary hysteresis occurred in 95% of lambs. The greatest changes in Q-LUSMGV occurred at the opening and closing pressures.ConclusionQ-LUSMGV detected changes in total and regional lung volume and offers objective quantification of LUS images, and may improve bedside discrimination of real-time changes in lung volume.ImpactLung ultrasound (LUS) offers continuous, radiation-free imaging that may play a role in assessing lung recruitment but may not detect small changes in lung volume.Mean greyscale image analysis using computer-assisted quantitative LUS (Q-LUSMGV) moderately correlated with changes in total and regional lung volume.Q-LUSMGV identified opening and closing pressure and pulmonary hysteresis in 95% of lambs.Computer-assisted image analysis may enhance LUS estimation of lung recruitment at the bedside.Future research should focus on improving precision prior to clinical translation.

Diffusing capacity of lungs in chronic obstructive pulmonary disease: gender, age, and race aspects

Introduction. Diffusion capacity of lungs is the second most important respiratory test after spirometry. The importance of assessing lung diffusion capacity in chronic obstructive pulmonary disease (COPD) is not given due attention, although this parameter reflects changes in functional lung volume and gas transport through the alveolar-capillary membrane, thereby providing more information about respiratory physiology than spirometry results. Diffusing capacity of the lung for carbon monoxide (DLCO) measurement is the standard in pulmonology, however, in recent years, close attention has been given to the determination of lung diffusion capacity for nitric oxide (DLNO), which gives better explanation of gas transport through the alveolar-capillary membrane compared to DLCO. Recent literature is actively discussing the inclusion of age, race, and gender aspects in spirometric reference equations that are used to assess spirometric parameters and lung diffusion capacity.Aim. To analyze the literature over the past five years, reflecting the views of modern researchers on methods for diagnosing lung diffusion capacity, as well as the contribution of age, race, and gender aspects to the assessment of this parameter in COPD.Materials and methods. The PubMed database was searched for information for the period 2017-2022 according to the selected inclusion criteria. Information requests included the following set of keywords: “diffusion capacity”, “chronic obstructive pulmonary disease”, “gender”, “age”, “race”, “DLNO”, “DLCO”. 123 articles were analyzed.Results. Recent evidence highlights the importance of including lung diffusivity in COPD prognostic programs. Determining the diffusion capacity of the lungs for nitric oxide may be a promising area of research soon. Gender and age considerations play an important role in the interpretation of spirometry data and lung diffusion capacity. The issue of including a racial trait in the assessment of the diffusing capacity of the lungs in COPD is in doubt.

Lung volume changes during apnoeas in preterm infants

ObjectiveMechanisms of non-invasive high-frequency oscillatory ventilation (nHFOV) in preterm infants are unclear. We aimed to compare lung volume changes during apnoeas in preterm infants on nHFOV and nasal continuous positive...

Respiratory bi-directional pressure and flow data collection device with thoracic and abdominal circumferential monitoring

Non-invasive pressure and flow data from Venturi-based sensors can be used with validated models to identify patient-specific lung mechanics. To validate applied respiratory models a secondary measurement is required. Rotary encoder-based tape measures were designed to capture change in circumference of a subject’s thorax and diaphragm. Circumferential changes can be correlated to measured or modelled change in lung volume and associated muscular recruitment measures (patient work of breathing). Hence, these simple measurement devices can expedite respiratory research, by adding low-cost, accessible, and clinically useful measurements.

Capnodynamic monitoring of lung volume and blood flow in response to increased positive end-expiratory pressure in moderate to severe COVID-19 pneumonia: an observational study

BackgroundThe optimal level of positive end-expiratory pressure (PEEP) during mechanical ventilation for COVID-19 pneumonia remains debated and should ideally be guided by responses in both lung volume and perfusion. Capnodynamic monitoring allows both end-expiratory lung volume ({text{EELV}}_{{{text{CO}}_{2} }}) and effective pulmonary blood flow (EPBF) to be determined at the bedside with ongoing ventilation.MethodsPatients with COVID-19-related moderate to severe respiratory failure underwent capnodynamic monitoring of {text{EELV}}_{{{text{CO}}_{2} }} and EPBF during a step increase in PEEP by 50% above the baseline (PEEPlow to PEEPhigh). The primary outcome was a > 20 mm Hg increase in arterial oxygen tension to inspired fraction of oxygen (P/F) ratio to define responders versus non-responders. Secondary outcomes included changes in physiological dead space and correlations with independently determined recruited lung volume and the recruitment-to-inflation ratio at an instantaneous, single breath decrease in PEEP. Mixed factor ANOVA for group mean differences and correlations by Pearson’s correlation coefficient are reported including their 95% confidence intervals.ResultsOf 27 patients studied, 15 responders increased the P/F ratio by 55 [24–86] mm Hg compared to 12 non-responders (p < 0.01) as PEEPlow (11 ± 2.7 cm H2O) was increased to PEEPhigh (18 ± 3.0 cm H2O). The {text{EELV}}_{{{text{CO}}_{2} }} was 461 [82–839] ml less in responders at PEEPlow (p = 0.02) but not statistically different between groups at PEEPhigh. Responders increased both {text{EELV}}_{{{text{CO}}_{2} }} and EPBF at PEEPhigh (r = 0.56 [0.18–0.83], p = 0.03). In contrast, non-responders demonstrated a negative correlation (r = − 0.65 [− 0.12 to − 0.89], p = 0.02) with increased lung volume associated with decreased pulmonary perfusion. Decreased (− 0.06 [− 0.02 to − 0.09] %, p < 0.01) dead space was observed in responders. The change in {text{EELV}}_{{{text{CO}}_{2} }} correlated with both the recruited lung volume (r = 0.85 [0.69–0.93], p < 0.01) and the recruitment-to-inflation ratio (r = 0.87 [0.74–0.94], p < 0.01).ConclusionsIn mechanically ventilated patients with moderate to severe COVID-19 respiratory failure, improved oxygenation in response to increased PEEP was associated with increased end-expiratory lung volume and pulmonary perfusion. The change in end-expiratory lung volume was positively correlated with the lung volume recruited and the recruitment-to-inflation ratio. This study demonstrates the feasibility of capnodynamic monitoring to assess physiological responses to PEEP at the bedside to facilitate an individualised setting of PEEP.Trial registration: NCT05082168 (18th October 2021).

Quantitative Evaluation of Chronic Obstructive Pulmonary Disease and Risk Prediction of Acute Exacerbation by High-Resolution Computed Tomography.

Objective It is imperative to popularize the tertiary prevention of chronic obstructive pulmonary disease (COPD) and to improve the diagnosis and treatment. Methods COPD patients were divided into mild (n = 18), moderate (n = 20), severe (n = 24), and extremely severe (n = 22) groups for performing high-resolution computed tomography (HRCT) and pulmonary function test. Serum procalcitonin (PCT) and high-sensitivity C-reactive protein (hs-CRP) were detected, and the occurrence rate of acute exacerbation COPD (AECOPD) was recorded during a 12-months follow-up period. Results With an increase in the severity grade, the HRCT indexes, including emphysema index (EI), 1st and 15th percentile of inspiratory attenuation distribution (Perc1 and Perc15), ratio of expiratory/inspiratory mean lung density (MLDex/in) and lung volume (LVex/in), and ratio of the wall thickness to the outer diameter of the lumen (TDR), as well as percentage of the wall area to the total cross-sectional area (WA%) were increased with a decreased change in relative lung volume with attenuation values between −860 and −950 HU (RVC−860to −950) and lumen area (Ai). These were correlated with the ratio of forced expiratory volume in 1 sec (FEV1) over forced vital capacity (FVC) (FEV1/FVC), the percentage of FEV1 the predicted value (FEV1%), and ratio of residual volume to total lung volume (RV/TLC). Body mass index, MLDex/in, FEV1%, FEV1/FVC, and PCT had a predictive value to AECOPD, with the combined AUC of 0.812. Conclusions HRCT imaging effectively classifies the severity of COPD, which combined with BMI, PFT, and serum PCT can predict the risk of AECOPD.

Lung ultrasound of the dependent lung detects real-time changes in lung volume in the preterm lamb

BackgroundEffective lung protective ventilation requires reliable, real-time estimation of lung volume at the bedside. Neonatal clinicians lack a readily available imaging tool for this purpose.ObjectiveTo determine the ability of lung...

Pre-oxygenation and apneic oxygenation in patients living with obesity - A review of novel techniques.

ABSTRACTMorbidly obese patients are in the group of patients, who can desaturate fast because of changes in lung volumes and reduction in Functional Residual Capasity due to obesity. There are novel methods to improve preoxygenation and to maintain oxygneation during intubation efforts. In this paper we present methods of apneic oxygenation for morbidly obese patients.

Pulmonary Recovery Following Corrective Surgery in Adult Patients With Severe Scoliosis: A Minimum of Five-Year Follow-Up.

BackgroundHalo gravity traction (HGT) has been reported to be a safe and effective adjunctive method for the management of scoliosis. However, the direct effects of HGT on the lung recovery of adult patients with scoliosis remain obscure.ObjectiveTo investigate changes in lung volume and pulmonary function in adult patients with severe scoliosis who underwent posterior spinal fusion concomitant with preoperative halo gravity traction.MethodsA total of 47 patients with a minimum 5-year follow-up who underwent posterior spinal instrumentation and fusion using preoperative halo–gravity traction were analyzed. Pulmonary function tests and three-dimensional CT were performed to evaluate changes in lung function and lung volume, respectively.ResultsThere was significant change in the Cobb angle of the major curve after halo gravity traction (P < 0.0001). Significant improvement in both Cobb angle (P < 0.0001) and thoracic kyphosis (P = 0.034) after corrective surgery was observed. Pulmonary function did not change significantly during traction. However, a significant decline in absolute and percent-predicted pulmonary function values was noted following surgery. The average change in lung volume did not show statistical differences during traction. At 5-year postoperative follow-up, the mean values revealed a significant increase in total lung volume (P < 0.0001) and concave lung volume (P < 0.0001) with surgical correction, but no statistically significant change in lung volume on the convex side (P = 0.57). Postoperative pulmonary complications occurred in nine cases with lower preoperative pulmonary function, indicating the importance of performing spirometry before corrective surgery.ConclusionsWe found that halo gravity traction prior to corrective surgery was less useful in improving pulmonary function in adult patients with severe scoliosis. However, these patients were expected to have increased lung volume after correction of the deformity.

The effect of antibiotic changes during treatment of cystic fibrosis pulmonary exacerbations

BackgroundAntibiotics are often changed during treatment of pulmonary exacerbations (PEx) in people with cystic fibrosis (CF) who have a poor clinical response. We aimed to characterize the reasons CF providers change antibiotics and examined the effects of antibiotic changes on lung function recovery. MethodsThis was a retrospective cohort study using the Toronto CF Database from 2009 to 2015 of adults and children with CF PEx treated with intravenous antibiotics. The co-primary outcome measure was absolute and relative change in forced expiratory lung volume in 1 s (FEV1) at end of treatment and follow-up. Secondary outcome assessed the proportion of patients returning to > 90% or > 100% previous baseline FEV1. ResultsA total of 399 PEx were included of which 105 had antibiotic changes. Reasons for antibiotic changes included change in antibiotic route prior to discharge (26%), drug reactions (20%), poor FEV1 response (25%), targeting additional microbes (16%) and lack of symptom improvement (13%). In our multivariable analysis, among non-responders (< 90% FEV1 recovery to baseline or lack of symptom improvement at the interim time point), a change in antibiotics was not associated with any significant difference in absolute or relative FEV1 at end of treatment or at follow-up. Antibiotic change in non-responders was not associated with improved return to 90% or 100% baseline FEV1 at end of treatment or follow-up. ConclusionsChanging antibiotics during CF PEx treatment in those with poor clinical response was not associated with any improved FEV1 response or return to baseline lung function.

Quantitative inspiratory-expiratory chest CT findings in COVID-19 survivors at the 6-month follow-up.

We evaluated pulmonary sequelae in COVID-19 survivors by quantitative inspiratory–expiratory chest CT (QCT) and explored abnormal pulmonary diffusion risk factors at the 6-month follow-up. This retrospective study enrolled 205 COVID-19 survivors with baseline CT data and QCT scans at 6-month follow-up. Patients without follow-up pulmonary function tests were excluded. All subjects were divided into group 1 (carbon monoxide diffusion capacity [DLCO] < 80% predicted, n = 88) and group 2 (DLCO ≥ 80% predicted, n = 117). Clinical characteristics and lung radiological changes were recorded. Semiquantitative total CT score (0–25) was calculated by adding five lobes scores (0–5) according to the range of lesion involvement (0: no involvement; 1: < 5%; 2: 5–25%; 3: 26–50%; 4: 51–75%; 5: > 75%). Data was analyzed by two-sample t-test, Spearman test, etc. 29% survivors showed air trapping by follow-up QCT. Semiquantitative CT score and QCT parameter of air trapping in group 1 were significantly greater than group 2 (p < 0.001). Decreased DLCO was negatively correlated with the follow-up CT score for ground-glass opacity (r = − 0.246, p = 0.003), reticulation (r = − 0.206, p = 0.002), air trapping (r = − 0.220, p = 0.002) and relative lung volume changes (r = − 0.265, p = 0.001). COVID-19 survivors with lung diffusion deficits at 6-month follow-up tended to develop air trapping, possibly due to small-airway impairment.