Sara L. S. Menezes

Effects of ELTGOL and Flutter VRP1®on the dynamic and static pulmonary volumes and on the secretion clearance of patients with bronchiectasis

BACKGROUND Although respiratory physical therapy is considered fundamental in the treatment of hypersecretive patients, there is little evidence of its physiological and therapeutic effects in bronchiectasis patients. OBJECTIVE To evaluate the acute physiological effects of ELTGOL and Flutter VRP1® in dynamic and static lung volumes in patients with bronchiectasis and, secondarily, to study the effect of these techniques in sputum elimination. METHODS Patients with clinical and radiological diagnosis of bronchiectasis were included. Patients underwent three interventions in a randomized order and with a one-week washout interval between them. Before all interventions patients inhaled two puffs of 100 mcg of salbutamol. There was a cough period of five minutes before and after the control protocol and the interventions (ELTGOL and Flutter VRP1®). After each cough series patients underwent assessments of dynamic and static lung volumes by spirometry and plethysmography. The expectorated secretions were collected during the interventions and during the second cough series, and quantified by its dry weight. RESULTS We studied 10 patients, two males and eight females (mean age: 55.9±18.1 years). After using Flutter VRP1®and ELTGOL there was a significant decrease in residual volume (RV), functional residual capacity (FRC) and total lung capacity (TLC) (p<0.05). There was a higher sputum production during ELTGOL compared with Control and Flutter VRP1® (p<0.05). CONCLUSION The ELTGOL and Flutter VRP1® techniques acutely reduced lung hyperinflation, but only the ELTGOL increased the removal of pulmonary secretions from patients with bronchiectasis.

Effects of uni- and bilateral phrenicotomy on active and passive respiratory mechanics in rats

Eighteen spontaneously breathing anesthetized rats were selected to belong to three groups: control (C), unilateral (U), and bilateral phrenicotomy (B). Eight days after surgery, the passive and active mechanical properties of the respiratory system, the shape of the occlusion pressure wave, the decay of inspiratory muscle activity during expiration and control of breathing were analysed. Passive and active elastances increased significantly from C to U and from U to B. Passive and active time constants decreased either in uni- or bilateral phrenicotomies. Passive and active resistances remained unaltered. The intensity of respiratory drive increased from C to U and B. In conclusion, uni- and bilateral phrenicotomies increase the elastic load of the respiratory system, because of both its passive and active components, which raised the respiratory neuromuscular drive of the remaining muscles. Consequently, minute ventilation remained unchanged. The higher frequency was allowed for, by a shorter time constant of the respiratory system and by a faster decay of post-inspiratory muscle activity.

Relationship between body balance, lung function, nutritional status and functional capacity in adults with cystic fibrosis

BACKGROUND Cystic fibrosis (CF) is a hereditary condition in which lung disease affects all patients. In addition to pulmonary involvement, the multisystemic components of CF cause significant physical limitations. However, the impact of lung function on balance control in CF has not been studied. OBJECTIVE To assess body balance in adults with CF and to test its possible associations with lung function, nutritional status, and functional capacity. METHOD This was a cross-sectional study in which 14 adults with CF underwent pulmonary function testing (spirometry, body plethysmography, and carbon monoxide diffusing capacity (DLco), respiratory muscle strength, 6-min walking distance (6MWD), Berg balance scale (BBS), nutritional analysis (body mass index and bioelectrical impedance), and stabilometry. Body balance was quantified using stabilometry; all participants performed the following two trials: opened base, eyes open (OBEO); closed base, eyes closed (CBEC). RESULTS In stabilometry, the median for the lateral range and anterior-posterior range in the CBEC trial was 0.10 (0.08-0.11) and 0.13 (0.11-0.22), respectively (p<0.05). The maximal inspiratory pressure (MIP) correlated inversely with the lateral standard deviation (ρ=-0.61; p<0.05) as the DLco correlated positively with the anterior-posterior range (ρ=0.54; p<0.05). There were significant relationships between body composition indexes and almost all stabilometric variables measured. There were no relationships of the BBS and 6MWD with the stabilometric variables. CONCLUSIONS In adults with CF, imbalance occurs mainly in the anterior-posterior direction and is especially associated with body composition.

Effect of continuous positive airway pressure on fluid absorption among patients with pleural effusion due to tuberculosis

BACKGROUND Tuberculosis (TB) remains as an important public health problem worldwide. The most common type is pulmonary TB, and the most prevalent form of extra-pulmonary disease among HIV-negative patients is pleural disease. OBJECTIVE The objective of the present study was to determine the effect of continuous positive airway pressure (CPAP) on fluid absorption among patients with pleural effusion due to TB. METHODS Twenty patients were randomized into two groups. The interventional group (n=10) received CPAP three times a week during the initial four weeks of anti-TB treatment, and the control group (n=10) received anti-TB drugs only. The primary endpoint was the volume of pleural fluid after four weeks of treatment. Both groups were submitted to thoracic computed tomography using three-dimensional image reconstruction. The Mann-Whitney test for independent samples and the Wilcoxon paired samples test were used for statistical analysis. The normal distribution samples were analyzed using the unpaired t test. RESULTS The reduction of pleural effusion volume was significantly greater in the intervention group (83.5%+/-SD 3.6) than in the control group (36.9%+/-SD 2.9; p<0.001), and the final dyspnea index was lower in the Intervention group than in the control group (p=0.002). CONCLUSION Our findings indicate that CPAP during the first month of TB treatment accelerates the absorption of pleural effusion, however, additional studies are needed to confirm these findings and evaluate the impact of CPAP on pleural sequelae after the end of anti-TB treatment. Article registered in the Clinical Trials under the number NCT00560521.

Respiratory changes in a murine model of spontaneous systemic lupus erythematosus.

The pathophysiology of systemic lupus erythematosus (SLE) has been very well described in many organs. However, the relation between extracellular matrix changes and lung dynamic mechanical behaviour deserves elucidation. To that end, pulmonary mechanics, lung morphometry and the amount of collagen and elastic fibres in the alveolar septa were analysed in mice with SLE [NZB/W (New Zealand Black/White) F1] and non-diseased NZW mice (control). Static (E(st)) and dynamic (E(dyn)) elastances, difference between dynamic and static elastances (DeltaE), airway resistance (R(aw)) and viscoelastic/inhomogeneous pressure (DeltaP(2)) were determined by the end-inflation occlusion method. Lungs were removed and prepared for histology. E(st), E(dyn), DeltaE and DeltaP(2) were higher in SLE than in control group, while R(aw) was similar in both groups. SLE group showed alveolar collapse and increased amount of elastic and collagen fibres. In conclusion, SLE mice showed an increase in elastic and viscoelastic/inhomogeneous pressures that was accompanied by deposition of collagen and elastic fibres in the alveolar septa.

Respiratory mechanics and pleural remodelling in pleurodesis induced by barium sulphate

The aim of this study was to determine whether an intrapleural injection of barium sulphate would produce pleurodesis in rats. Additionally, respiratory mechanics and pleural remodelling were analysed. Single intrapleural injection of barium sulphate (100%) or saline was given to Wistar rats. Respiratory system, lung, and chest wall elastic, resistive and viscoelastic/inhomogeneous pressures were measured by the end-inflation occlusion method at 2 and 30 days after injection. The pleura were examined for gross and histopathological evidence of pleural inflammation and fibrosis, and the underlying lungs were also studied by morphometry. All pulmonary mechanical parameters increased at day 2, but were not different from control at 30 days after injection. Chest wall mechanical parameters did not change. Macroscopic evaluation demonstrated pleural adherence without haemothorax. Histopathologic analysis showed pleural inflammation and fibrosis. There was no alveolar inflammation or fibrosis in both groups. In conclusion, barium sulphate induced pleurodesis with either no changes in respiratory mechanics or lung lesion at day 30.

Selecting the best ventilator hyperinflation technique based on physiologic markers: A randomized controlled crossover study

Background: Ventilator hyperinflation (VHI) is effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated subjects; however, there are no recommendations for the best ventilator settings to perform the technique. Objective: To compare six modes of VHI, concerning physiological markers of efficacy and safety criteria to support the selection of optimal settings. Methods: Thirty mechanically ventilated patients underwent six modes of VHI in a randomized order. The delivered volume, expiratory flow bias criteria, overdistension, patient–ventilator asynchronies and hemodynamic variables were assessed during the interventions. Results: Volume‐controlled ventilation with inspiratory flow of 20 lpm (VC‐CMV20) and pressure support ventilation (PSV) achieved the best effectiveness scores (P < 0.05). The target peak pressure of 40 cmH2O was associated with a high incidence of overdistension. PSV showed a lower incidence of patient–ventilator asynchronies. Conclusions: The modes VC‐CMV20 and PSV are the most effective for VHI. Alveolar overdistension and patient–ventilator asynchronies must be considered when applying VHI.

ASSESSMENT OF MAXIMUM INSPIRATORY PRESSURE IN NON-COOPERATIVE CRITICAL PATIENTS: COMPARISON BETWEEN TWO METHODS

Background: Although mechanical ventilation is necessary for treating acute respiratory insufficiency, it may be associated with deconditioning and respiratory muscle dysfunction. Maximal inspiratory pressure (MIP) evaluation is used to estimate inspiratory muscle strength in artificially ventilated patients, but there is no definition as to the best way to make this measurement. Objective: To compare two methods for MIP evaluation, using four different protocols, among non-cooperative artificially ventilated patients. Method: Thirty non-cooperative patients undergoing the process of weaning off mechanical ventilation were evaluated. In accordance with block randomization, the simple occlusion method (OM) or the unidirectional valve method (UV) was applied to each patient for time periods of 20 and 40 seconds. Additionally, during the 40s measurements, the MIP value at 30s was recorded. Results: The MIP values were higher at 40s than at 20s, both from OM (48.2 ± 21.7 vs. 36 ± 18.7 cmH 2 O; p< 0.001) and from UV (56.6 ± 23.3 vs. 43.4 ± 24 cmH 2 O; p< 0.001). The MaxIP values were higher from UV at 40s (UV40) than from OM at 40s (OM40) (56.6 ± 23.3 vs. 48.2 ± 21.7 cmH 2 O; p< 0.001). There was a difference between UV at 30 and 40s (51.5 ± 20.8 vs. 56.6 ± 23.3 cmH 2 O; p< 0.001). Conclusion: Among non-cooperative patients, higher MIP values were obtained from the unidirectional valve method with 40s of occlusion than from the other protocols evaluated.Maximal inspiratory pressure evaluation among non-cooperative critical patients: comparison between two methods Background: Although mechanical ventilation is necessary for treating acute respiratory insufficiency, it may be associated with deconditioning and respiratory muscle dysfunction. Maximal inspiratory pressure (MIP) evaluation is used to estimate inspiratory muscle strength in artificially ventilated patients, but there is no definition as to the best way to make this measurement. Objective: To compare two methods for MIP evaluation, using four different protocols, among non-cooperative artificially ventilated patients. Method: Thirty non-cooperative patients undergoing the process of weaning off mechanical ventilation were evaluated. In accordance with block randomization, the simple occlusion method (OM) or the unidirectional valve method (UV) was applied to each patient for time periods of 20 and 40 seconds. Additionally, during the 40s measurements, the MIP value at 30s was recorded. Results: The MIP values were higher at 40s than at 20s, both from OM (48.2 ± 21.7 vs. 36 ± 18.7 cmH 2 O; p< 0.001) and from UV (56.6 ± 23.3 vs. 43.4 ± 24 cmH 2 O; p< 0.001). The MIP values were higher from UV at 40s (UV40) than from OM at 40s (OM40) (56.6 ± 23.3 vs. 48.2 ± 21.7 cmH 2 O; p< 0.001). There was a difference between UV at 30 and 40s (51.5 ± 20.8 vs. 56.6 ± 23.3 cmH 2 O; p< 0.001). Conclusion: Among non-cooperative patients, higher MIP values were obtained from the unidirectional valve method with 40s of occlusion than from the other protocols evaluated.