Marcelo Alcantara Holanda

Influência das máscaras facial total, facial e nasal nos efeitos adversos agudos durante ventilação não-invasiva

OBJECTIVE Failure of noninvasive ventilation (NIV) has been associated with short-term adverse effects related to the use of masks. The aim of this study was to compare the incidence, type and intensity of adverse effects, as well as the comfort, of total face masks (TFMs), facial masks (FMs) and nasal masks (NMs) during NIV. METHODS This was a randomized crossover trial involving 24 healthy volunteers submitted to six sessions of NIV in bilevel positive airway pressure mode using the TFM, FM and NM masks at low and moderate-to-high pressure levels. A written questionnaire was applied in order to evaluate eleven specific adverse effects related to the use of the masks. Comfort was assessed using a visual analog scale. The CO2 exhaled into the ventilator circuit was measured between the mask and the exhalation port. RESULTS The performance of the TFM was similar to that of the NM and FM in terms of comfort scores. Higher pressure levels reduced comfort and increased adverse effects, regardless of the mask type. When the TFM was used, there were fewer air leaks and less pain at the nose bridge, although there was greater oronasal dryness and claustrophobia. Air leaks were most pronounced when the FM was used. The partial pressure of exhaled CO2 entering the ventilator circuit was zero for the TFM. CONCLUSIONS The short-term adverse effects caused by NIV interfaces are related to mask type and pressure settings. The TFM is a reliable alternative to the NM and FM. Rebreathing of CO2 from the circuit is less likely to occur when a TFM is used.

Continuous Positive Airway Pressure Effects on Regional Lung Aeration in Patients With COPD: A High-Resolution CT Scan Study

BACKGROUND The effects of nasal continuous positive airway pressure (CPAP) on the lung parenchyma of patients with COPD, to our knowledge, have never been assessed by high-resolution CT (HRCT) scanning. METHODS HRCT scans were obtained at the apex, hilum, and basis of the lungs at functional residual capacity while on spontaneous respiration and at the end of CPAP trials of 5 cm water (H(2)O), 10 cm H(2)O, and 15 cm H(2)O in 11 stable patients with COPD and eight healthy volunteers. Lung aeration was assessed by quantitative density parameters and by qualitative analysis of each CT image after processing by means of a density-based color-mask computational algorithm. The quantitative parameters were density histograms, the relative area of the lungs with attenuation values < -950 Hounsfield units (percentage of hyperaerated areas) and the 15th percentile (the density value separating the 15% voxels of least density). RESULTS A CPAP of 5 cm H(2)O caused little increase in lung aeration in both groups, but in some patients with COPD, CPAP deflated some regions of the lungs. CPAP levels of 10 cm H(2)O and 15 cm H(2)O increased the emphysematous zones in all sectors of the lungs, including dorsal and apical regions in patients with COPD compared to little hyperaeration predominantly in the ventral areas in healthy volunteers. CONCLUSIONS Nasal CPAP causes variable effects on regional lung aeration in relation to the applied pressure and the regional distribution of emphysema in patients with COPD. Low pressure levels may cause regional lung deflation in some patients. High levels increase the emphysematous areas wherever they are located inside the lungs.

Avaliação computacional de enfisema pulmonar em TC: comparação entre um sistema desenvolvido localmente e um sistema de uso livre

OBJECTIVE: To present a locally developed system of computer vision for use with HRCT images, designated SIStema para a Deteccao e a quantificacao de Enfisema Pulmonar (SISDEP, System to Detect and Quantify Pulmonary Emphysema), and to compare this system with a freeware system tool. METHODS: Thirty-three HRCT images scanned at the apex, hilum and base of the lungs of 11 patients with COPD were analyzed. The SISDEP was compared with the Osiris Medical Imaging Software Program regarding lung parenchyma segmentation, precision of the measurement of the cross-sectional area of the lungs in mm2, mean lung density (MLD), relative area (RA) of the lung occupied by voxels with attenuation values < -950 hounsfield units (ra -950), 15th percentile point (perc15) and visualization of hyperinflated areas using a color mask. RESULTS: Although both computational systems were efficient in segmenting the lungs, the SISDEP performed this task automatically and more rapidly. There were significant correlations between the two systems in terms of the results obtained for lung cross-sectional area, MLD, RA -950 and Perc15 (r2 = 0.99, 0.99, 0.99 and 1.00, respectively). The color mask tool of the SISDEP allowed excellent visualization of hyperinflated areas, discriminating them from normal areas. CONCLUSIONS: The SISDEP was efficient in segmenting the lungs and quantifying lung hyperinflation, presenting an excellent correlation with the Osiris system. The SISDEP constitutes a promising computational tool for diagnosing and assessing the progression of emphysema in HRCT images of COPD patients.

Ventilação mecânica na doença pulmonar obstrutiva crônica (DPOC) descompensada

A sigla DPOC (Doenca Pulmonar Obstrutiva Cronica) denomina um grupo de entidades nosologicas respiratorias que acarretam obstrucao cronica ao fluxo aereo de carater fixo ou parcialmente reversivel, tendo como alteracoes fisio-patologicas de base, graus variaveis de bronquite cronica e enfisema pulmonar.

Identification and Quantification of Pulmonary Emphysema through Pseudocolors

Chronic Obstructive Pulmonary Disease (COPD) is a world health problem with high morbidity and mortality. High-Resolution Computed Tomography (HRCT), is an excellent tool for early detection of emphysema component of COPD. Despite this fact, HRCT presents limitations inherent to the subjective analysis of the gray scale image that directly compromises the accuracy for both diagnosis and precise determination of the disease extension. The objective of this paper is present a colored mask algorithm (CMA) to identify and quantify the emphysema, enhancing its visualization through pseudocolors. We studied 21 images of 7 patients with COPD and 1 healthy volunteer. The CMA applies colors to the segmented lungs according to pre-defined ranges of Hounsfield units. CMA automatically calculates the relative area occupied by tomographic densities within the pre-defined ranges, allowing precise quantification of diseased and normal parenchyma. Future works are needed in order to validate the incorporation of the CMA in the image assessment of emphysema in COPD patients.

3D Lung Fissure Segmentation in TC images based in Textures

Among all cancers, lung cancer (LC) is the most common of all malignant tumors. In order to obtain a more effective segmentation of pulmonary fissures, independent to other structures present in the CT scan, this paper proposes the segmentation of 3D fissures using texture measures and Artificial Neural Networks (ANN). The results of this study are based on voxels classified as fissure through the proposed method compared to the gold standard set by an expert. The results were analyzed using similarity coefficient rate of 95.6%, the rate sensitivity of 71.1% and specificity of 95.6% rate. Thus, it is possible to identify the job has a gain due to not using segmentation of other pulmonary structures and does not require the use of pulmonary atlas.

Automatic Segmentation and Measurement of the Lungs in healthy persons and in patients with Chronic Obstructive Pulmonary Disease in CT Images

Nowadays, Computed Tomography (CT) of the thorax is the most accurate image technique for the diagnosis of the majority of the lung and chest diseases. Despite of this fact there are still limitations of CT in diagnosing and specially quantifying lung diseases such as emphysema. The automatic segmentation and measurement of the lungs and thoracic structures can improve by image processing techniques. These techniques enhance the visualization of the lungs and the chest wall. The present paper presents a method of automatic classification capable to segment and measure the lungs and the thoracic cavity both in healthy volunteers and in patients with Chronic Obstructive Pulmonary Disease (COPD) in prone positions based on technique of region growing. With the region growing method, based on computer programs, it is possible to segment and measure the aerated lung and the thoracic cavity.

Ventilação não-invasiva com pressão positiva em pacientes com insuficiência respiratória aguda: fatores associados à falha ou ao sucesso

Objective: To evaluate the effects of non-invasive positive pressure ventilation (NIPPV) on acute respiratory failure and to identify the factors associated with its failure or success. Patients and methods: This open and prospective study analyzed 60 episodes of NIPPV use in 53 patients with respiratory failure. Results: In 37 occasions (62%), the patients were successfully ventilated with NIPPV (Success Group, SG) whereas in 23 episodes (38%) intubation was necessary (Failure Group, FG). FG patients showed a higher Apache II score (30.4 ± 9 versus 22.2 ± 8, p = 0.001). The use of NIPPV reduced respiratory rate after 2 hs. This reduction was less evident in FG (from 33 ± 9 to 30 ± 8 bpm, p = 0.094) than in SG (from 39 ± 11 to 28 ± 9 bpm, p < 0.001). PaO2 increased from 62 ± 22 to 101 ± 65 mmHg, (p < 0.001) with no differences between groups. Among patients with hypercapnia, PaCO2 level decreased in SG (from 76 ± 20 to 68 ± 21mmHg, p = 0.032) but not in FG (from 89 ± 23 to 93 ± 40mmHg, p = 0.54). Arterial pH increased in SG (from 7.25 ± 0.10 to 7.34 ± 0.11, p = 0.007) and not in FG (from 7.24 ± 0.07 to 7.21 ± 0.12, p = 0.48). NIPPV was used for longer in SG (3.4 ± 2.5 versus 2.3 ± 2 days, p = 0.003). Higher IPAP levels were used in SG (13.2 ± 3 versus 11 ± 4cmH2O, p = 0.02). The 10 patients (17%) who died, all belonged to FG. Skin lesions at the site of mask contact was the most common complication of NIPPV (5, 8%). NIPPV was efficient in treating acute respiratory failure in 2/3 of patients. The factors associated with failure were: greater severity of the illness, smaller reduction in the respiratory rate, no improvement of respiratory acidosis in 2 h and use of lower IPAP levels. The high mortality rate observed in FG (10, 43%) justifies efforts to optimize NIPPV implementation and to recognize its failure, as early as possible, in order to avoid delays in endotracheal intubation.

Concordância entre o aspirado traqueal e o lavado broncoalveolar no diagnóstico das pneumonias associadas à ventilação mecânica

INTRODUCAO: Os exames de cultura e o exame bacterioscopico pelo metodo de coloracao de Gram (GRAM) do aspirado traqueal ainda sao objeto de controversias com relacao ao diagnostico etiologico na pneumonia associada a ventilacao mecânica (PAV). OBJETIVO: Avaliar a concordância entre os resultados do GRAM e da cultura quantitativa do aspirado traqueal e do lavado broncoalveolar nos pacientes com PAV. METODO: Foram estudados de modo prospectivo os pacientes internados no periodo de outubro de 2001 a agosto de 2002, que estavam ha mais de 48hs sob ventilacao mecânica, e que apresentavam suspeita clinica de PAV. No momento da suspeita clinica foi realizado o aspirado traqueal seguido do lavado broncoalveolar. O diagnostico de PAV foi confirmado com a suspeita clinica associada a cultura quantitativa do lavado broncoalveolar 104ufc/ml. RESULTADOS: Dos 119 pacientes sob ventilacao mecânica, 32 (26,8%) tiveram suspeita clinica de PAV, com confirmacao diagnostica em 25 (78%) deles. A comparacao entre o GRAM do aspirado traqueal e a cultura do lavado broncoalveolar mostrou uma moderada concordância (coeficiente de Kappa de 0,56). Houve concordância entre a cultura quantitativa do aspirado traqueal e do lavado broncoalveolar em 22/25 (88%) e discordância em 3/25 (12%) casos (coeficiente de Kappa de 0,71). A sensibilidade e a especificidade do aspirado traqueal para o diagnostico de PAV com o ponto de corte 10 6 ufc/ml foram de 71% e 72%, respectivamente. CONCLUSAO: A combinacao do GRAM com a cultura quantitativa do aspirado traqueal pode contribuir para a avaliacao diagnostica da PAV.

Influences of Duration of Inspiratory Effort, Respiratory Mechanics, and Ventilator Type on Asynchrony With Pressure Support and Proportional Assist Ventilation

BACKGROUND: Pressure support ventilation (PSV) is often associated with patient-ventilator asynchrony. Proportional assist ventilation (PAV) offers inspiratory assistance proportional to patient effort, minimizing patient-ventilator asynchrony. The objective of this study was to evaluate the influence of respiratory mechanics and patient effort on patient-ventilator asynchrony during PSV and PAV plus (PAV+). METHODS: We used a mechanical lung simulator and studied 3 respiratory mechanics profiles (normal, obstructive, and restrictive), with variations in the duration of inspiratory effort: 0.5, 1.0, 1.5, and 2.0 s. The Auto-Trak system was studied in ventilators when available. Outcome measures included inspiratory trigger delay, expiratory trigger asynchrony, and tidal volume (VT). RESULTS: Inspiratory trigger delay was greater in the obstructive respiratory mechanics profile and greatest with a effort of 2.0 s (160 ms); cycling asynchrony, particularly delayed cycling, was common in the obstructive profile, whereas the restrictive profile was associated with premature cycling. In comparison with PSV, PAV+ improved patient-ventilator synchrony, with a shorter triggering delay (28 ms vs 116 ms) and no cycling asynchrony in the restrictive profile. VT was lower with PAV+ than with PSV (630 mL vs 837 mL), as it was with the single-limb circuit ventilator (570 mL vs 837 mL). PAV+ mode was associated with longer cycling delays than were the other ventilation modes, especially for the obstructive profile and higher effort values. Auto-Trak eliminated automatic triggering. CONCLUSIONS: Mechanical ventilation asynchrony was influenced by effort, respiratory mechanics, ventilator type, and ventilation mode. In PSV mode, delayed cycling was associated with shorter effort in obstructive respiratory mechanics profiles, whereas premature cycling was more common with longer effort and a restrictive profile. PAV+ prevented premature cycling but not delayed cycling, especially in obstructive respiratory mechanics profiles, and it was associated with a lower VT.