OBJECTIVETo evaluate the applicability of electrical impedance equipment in assessing local lung volume during different PEEP ventilation and at different respiratory rate in neonatal piglets.

METHODSElectrical impedance measurements (EIM) were performed on 6 healthy newborn piglets (age 4 +/- 1 d, weight 1.66 +/- 0.31 kg) using 8 electrodes distributed to 4 quadrants of the lung (left, right, upper, lower). Tidal impedance and functional residual impedance changes during PEEP levels of 2, 4, 6 and 8 cm H2O and frequencies ranging from 0.5 to 15 Hz were investigated.

RESULTSThe sum of regional tidal impedance obtained from four quadrants, significantly reflected tidal volume (VT) measured by a pneumotachograph during both frequency and PEEP changed (r2 = 0.98). A decrease of PEEP 4 to 2 cm H2O caused a significant increase in total tidal impedance (TTI) as well as in VT (P < 0.01 and P < 0.05); whereas an increase in frequency from 0.5 to 15 Hz was associated with a significant decrease in both TTI and VT (P < 0.05 and P < 0.01). Increased frequency had a balancing effect on air distribution, whereas higher PEEP did not result in more homogeneous ventilation. Minimal impedance values (FRI) (surrogate variable for FRC) showed that total FRI significantly decreased with increasing PEEP level.

CONCLUSIONSEIM demonstrated good applicability to assess changes in thoracic gas volume. It is highly suggested that this method could be considered and further studied as a non-invasive bedside method to monitor continuously regional lung ventilation of neonates under any mode of mechanical ventilation.

Animals ; Animals, Newborn ; Electric Impedance ; Lung Volume Measurements ; methods ; Positive-Pressure Respiration ; Respiratory Rate ; Swine

Breath Tests ; methods ; Child ; Humans ; Infant ; Lung Diseases ; diagnosis ; physiopathology ; Lung Volume Measurements ; Maximal Voluntary Ventilation ; Respiratory Function Tests ; Tidal Volume

Spirometry is a physiological test for assessing the functional aspect of the lungs using an objective indicator to measure the maximum amount of air that a patient can inhale and exhale. Acceptable spirometry testing needs to be conducted three times by an acceptable and reproducible method for determining forced vital capacity (FVC). Until the results of three tests meet the criteria of reproducibility, the test should be repeated up to eight times. Interpretation of spirometry should be clear, concise, and informative. Additionally, spirometry should guarantee optimal quality prior to the interpreting spirometry results. Our guideline adopts a fixed normal predictive value instead of the lower limit of normal as the reference value because fixed value is more convenient and also accepts FVC instead of vital capacity (VC) because measurement of VC using a spirometer is impossible. The bronchodilator test is a method for measuring the changes in lung capacity after inhaling a short-acting β-agonist that dilates the airway. When an obstructive ventilatory defect is observed, this test helps to diagnose and evaluate asthma and chronic obstructive pulmonary disease by measuring reversibility with the use of an inhaled bronchodilator. A positive response to a bronchodilator is generally defined as an increase of ≥12% and ≥200 mL as an absolute value compared with a baseline in either forced expiratory volume at 1 second or FVC.
Asthma ; Bronchodilator Agents ; Forced Expiratory Volume ; Humans ; Inhalation ; Lung ; Lung Volume Measurements ; Methods ; Pulmonary Disease, Chronic Obstructive ; Reference Values ; Spirometry* ; Vital Capacity

CT colonography is a promising technique that provides both multiplanar and endoluminal perspective of the air-filled, distended, cleaned colon. "Virtual colonoscopy" refers to computer-simulated 3D endoscopic visualization of the colonic mucosal surface. Unlike barium enema and conventional colonoscopy, CT colonography can give cross- sectional and endoluminal images of the colon and enables to image extracolic abnormality. CT colonography offers potential advantages over colonoscopy in that it causes little discomfort to the patient, and does not need sedation. It is more accurate in spatial location of lesions and creates no complication. To date, most studies assessing CT colonography have focused in technical development, less aggressive bowel preparation, and computer-aided diagnosis of polyp detection. In the future, CT colonography would be a diagnostic and screening tool for the colorectal polyp and cancer.
Humans ; Imaging, Three-Dimensional ; Liver Diseases/diagnosis/*radiography ; Lung Volume Measurements ; Pulmonary Veins/radiography ; Tomography, Spiral Computed/instrumentation/*methods

This study was conducted to observe effects of two methods of setting positive endexpiratory pressure (PEEP) based on the pressure-volume (PV) curve. After lung injury was induced by oleic acid in six mongrel adult dogs, the inflation PV curve was traced and the lower inflection point (LIP) was measured. The 'PEEP(INF)' was defined as LIP+2 cmH2O. After recruitment maneuver to move the lung physiology to the deflation limb of PV curve, decremental PEEP was applied. The lowest level of PEEP that did not result in a significant drop in PaO2 was defined as the 'PEEP(DEF)'. Arterial blood gases, lung mechanics, hemodynamics, and lung volumes (measured on computed tomography during end-expiratory pause) were measured at PEEP of 0 cmH2O, PEEP(INF) and PEEP(DEF) sequentially. The median PEEP(INF) was 13.4 cm H2O (interquartile range, 12.5-14.3) and median PEEP(DEF) was 12.0 cm H2O (10.0-16.5) (p=0.813). PEEP(DEF) was associated with significantly higher PaO2 and lung volumes, and significantly lower shunt fraction and cardiac index when compared to PEEP(INF) (p<0.05). Setting the PEEP based on the deflation limb of the PV curve was useful in improving oxygenation and lung volumes in a canine lung injury model.
Animals ; Dogs ; Lung/pathology ; *Lung Injury ; Lung Volume Measurements/*methods ; Male ; Oxygen/metabolism ; Positive-Pressure Respiration/*methods ; Pressure ; Pulmonary Gas Exchange ; Radiography, Thoracic/methods ; Tomography, X-Ray Computed/*methods

BACKGROUNDNow lung volume reduction surgery (LVRS) has become one of the most effective methods for the management of some cases of severe chronic obstructive pulmonary disease (COPD). We evaluated the mid-term effects of LVRS on pulmonary function in patients with severe COPD.

METHODSTen male patients with severe COPD aged 38 - 70 years underwent LVRS and their pulmonary function was assessed before, 3 months and 3 years after surgery. The spirometric and gas exchange parameters included residual volume, total lung capacity, inspiratory capacity, forced vital capacity, forced expiratory volume in one second, diffusion capacity for CO, and arterial blood gas. A 6-minute walk distance (6MWD) test was performed.

RESULTSAs to preoperative assessment, most spirometric parameters and 6MWD were significantly improved after 3 months and slightly 3 years after LVRS. Gas exchange parameters were significantly improved 3 months after surgery, but returned to the preoperative levels after 3 years.

CONCLUSIONSLVRS may significantly improve pulmonary function in patients with severe COPD indicating for LVRS. Mid-term pulmonary function 3 years after surgery can be decreased to the level at 3 months after surgery. Three years after LVRS, lung volume and pulmonary ventilation function can be significantly improved, but the improvement in gas exchange function was not significant.

Adult ; Aged ; Exercise Tolerance ; Humans ; Lung Volume Measurements ; Male ; Middle Aged ; Pneumonectomy ; adverse effects ; methods ; Pulmonary Disease, Chronic Obstructive ; pathology ; physiopathology ; surgery ; Respiratory Function Tests ; Time Factors