Residual Volume Levels Research Articles

Maximum inspiratory and expiratory pressures in the pre and postoperative periods of patients with incisional abdominal hernia corrected by Lázaro da Silva technique.

To verify the effect of longitudinal abdominal incisional herniorrhaphy on respiratory muscle pressure. The technique of incisional herniorrhaphy used was proposed by Lázaro da Silva. To measure the pressure, we used a water manometer in 20 patients, median age 48.5 years (range 24 70). We analyzed the maximum inspiratory pressure at the level of residual volume (IP-RV) and functional residual capacity (IP-FRC) and the maximum expiratory pressure of functional residual capacity (EP-FRC) and total lung capacity (EP-TLC) in the preoperative and late postoperative (40 90 days) periods, in 13 patients with large incisional hernias and in 7 patients with medium incisional hernias. There was a significant increase in IP-FRC (p = 0.027), IP-RV (p = 0.011) and EP-TLC (p = 0.003) in patients with large incisional hernias. EP-FRC increased, but not significantly. In patients with medium incisional hernias, the changes were not significant. Surgical correction of large incisional hernias improves the function of the breathing muscles; however, surgery for medium incisional hernias does not alter this function.

Dysfunction of respiratory system in patients with diabetes mellitus and coronary artery disease

Aims: we aimed to estimate the main parameters characterizing respiratory pulmonary function in patients with isolated type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD), as well as with their combination.
 Materials and methods: the study included 198 patients divided into 3 groups: I with isolated CAD [94 (47.5%)], II with T2DM without the signs of CAD [64 (32.3%)], III with combined CAD and T2DM [40 (20.2%)]. The assessment of carbohydrate and lipid metabolism, as well as the measurement of inflammatory markers were performed using unified clinical and biochemical methods. Respiratory pulmonary function and diffusion lung capacity (Dlco) were assessed using Elite Dl-220v body plethysmograph.
 Results: the parameters reflecting the respiratory pulmonary function and the level of gas diffusion through alveolar-capillary membrane (ACM) in patients with CAD both with and without diabetes was within the normal values. The exception was the level of residual volume, which was below the prognostic values in all the studied groups. At the same time, in diabetic patients with CAD the values of forced and slow vital lung capacity, forced expiratory volume for 1-second, as well as the level of diffusion were significantly lower as compared to the corresponding values in patients with isolated CAD and didnt differ in comparison with the values of diabetic patients except for the level of diffusion. It should be noted that a number of respiratory parameters had a correlation relationships with glycemic level, inflammatory markers and with the indicators characterizing dyslipidemia and myocardial dysfunction.
 Conclusions: in the course of the study it was found out that the diabetic patients had respiratory system dysfunction in comparison to the patients with isolated CAD. The presence of diabetes in patients with CAD worsens not only the somatic background but probably contributes to the respiratory dysfunction in the form of lower velocity and volumetric parameters, but also in the indicator showing respiratory metabolism.

Reversibility of the Pulmonary Function Based on the Partial Flow-volume Curve Predicts the Efficacy of Bronchodilator Therapy for Treating Chronic Cough

Partial expiratory flow-volume curves have the potential to detect mild bronchoconstriction because they are not affected by the modulatory effects of deep inspiration. The aim of this study was to investigate the relationship between the efficacy of bronchodilator therapy (BDT) in treating the cough and to assess the increase in the expiratory flow of the partial flow-volume curve at 40% above the residual volume level (PEF40) caused by treatment with a short-acting beta-2 agonist (SABA) in patients with chronic nonproductive cough. We measured the reversibility of PEF40 caused by a SABA in 42 patients with chronic nonproductive cough at visit 1 (day 0). The patients received BDT for six days. The visual analogue scale (VAS) was used to assess the efficacy of BDT in treating coughing at visit 2 (day 7) (0 mm, 'no cough;' 100 mm, 'no change in coughing'). Reversibility of the PEF40 was correlated (r=0.690, p<0.001) with the VAS score determined at visit 2 and was higher in the patients with cough variant asthma (CVA) (44.9 ± 18.3%) than in those with atopic cough (13.4 ± 10.4%) (p<0.01). Reversibility of the PEF40 predicted the efficacy of BDT in patients with chronic nonproductive cough and helped to identify patients with CVA.

Heightened cough response to bronchoconstriction in cough variant asthma

The pathophysiology of cough variant asthma (CVA) is poorly understood. We compared bronchoconstriction-triggered cough between CVA patients and normal control (NC) subjects. There were two protocols in the study. We measured bronchial responsiveness to methacholine (MCh) and counted the number of coughs in nine CVA patients and seven NC subjects (study A). Using partial and full flow-volume curves, expiratory flow of the partial flow-volume curve at 40% above residual volume level (PEF40) and FEV(1) were used to measure bronchoconstriction. Mild bronchoconstriction was defined as a 35% fall in PEF40 (PC(35) -PEF40), and more severe bronchoconstriction as a 20% fall in FEV1 (PC20) -FEV(1) ). In study B, the same measurements were obtained in six CVA patients before and after therapy. In study A, more coughs were provoked at PC35 -PEF40 in CVA patients (median, 60 coughs/32 min post challenge; range, 12-135) than in NC subjects (median, 0/32 min; range, 0-13; P < 0.05). At PC20 -FEV1 , more coughs were provoked in CVA patients (median, 60/32 min; range, 12-150) than in NC subjects (median, 20/32 min; range, 0-54; P < 0.05). In study B, the six CVA patients who underwent re-examination after treatment had less coughs at PC35 -PEF40 (median, 3/32 min; range, 0-14) and PC(20) -FEV1 (median, 13/32 min; range, 3-26) after therapy than before therapy (median, 54/32 min; range, 33-125 and 52/32 min, 45-96, respectively; P < 0.05). We identified heightened cough response to bronchoconstriction as a feature of CVA.

SU‐E‐T‐41: Measurement and Modeling of the Gross Tumor Volume Shrinkage of Lung Tumors as a Function of Delivered Therapeutic Dose

Purpose: To measure quantitatively in‐vivo shrinkage of gross tumor volume (GTV) using CT imaging and model GTV as a function of delivered dose during treatment. Methods: The GTV of three selected non‐small cell lung tumors were outlined on CT images acquired weekly during treatment course with regular fractionated regimens of 180 cGy over 35 fractions. These patients have well defined lesions in the middle of the lung where the GTV has high contrast compared to lung and other tissues. The GTV variations were measured as a function of delivered dose. Then, GTV‐dose curves were fitted with three exponential functions with linear and linear‐quadratic dose dependence that decreases to zero or certain residual volume levels. Results: The GTV shrinks exponentially as a function of dose through the treatment course. However, the GTV does not decrease to zero volume by the end of treatment. Among the three different formulas used to fit the GTV‐dose data, it was found that the exponential function that decays linearly with delivered dose to a certain volume level provides the best fitting formula of the GTV shrinkage. Alpha obtained from non‐linear curve fitting of the three patients varied by less than a factor of 2. The normalized residual volumes were within a factor of 3 and was not influenced by the initial GTVˈs which varied by more than a factor of 20. Conclusions: Neither a simple exponential function with a linear dose decay nor a complicated exponential function with linear‐quadratic dose decay, fit well GTV response as a function of dose through the treatment course. The linear exponential decay function to non‐zero volume level provided the best fitting formula to GTV‐dose data. This might be due to the necrotic core of the tumor that is less responsive to radiotherapy.

Respiratory Muscle Strength and Hemodynamics in Chronic Heart Failure

To examine whether respiratory muscle weakness is associated with cardiac function and/or exercise capacity in chronic heart failure (CHF), 23 patients with CHF were evaluated with respiratory muscle strength, pulmonary function tests, cardiac catheterization, and exercise test. The subjects were divided into three groups on their New York Heart Association (NYHA) functional class. Group A consisted of 13 patients with NYHA functional classification class 3 or 4, group B consisted of 10 patients with NYHA classification class 2, and group C consisted of 15 age-matched normal controls. Respiratory muscle strength was assessed with maximal static inspiratory mouth pressure at residual volume level and expiratory mouth pressure at total lung capacity level (PImax, PEmax, respectively). Pulmonary functions in patients with CHF showed almost normal. PImax in group A was significantly less than that in group B or C, although PImax in group B was not significantly different from that in group C. In the patients with CHF, PImax correlated positively with cardiac index and maximal oxygen consumption (r = 0.460 and r = 0.503, p < 0.05, respectively). These findings suggest that inspiratory muscle strength, which was impaired in patients with severe CHF, may be dependent on cardiac function and may be one of the limiting factors on impaired exercise capacity in the patients with CHF.

Respiratory muscle force and ventilatory function in adolescents

In 94 girls and 90 boys, aged 12.5-20.3 yr, the relationship of respiratory pressures or forces with lung volumes and ventilatory flows was studied. There was great variability in respiratory muscle performance, which helps to explain differences in lung volumes between individuals. Respiratory muscle force increases almost proportionally with thoracic dimensions, so that inspiratory and expiratory pressures generated at the level of residual volume (RV), functional residual capacity (FRC) and total lung capacity (TLC) are approximately constant with age. In the oldest boys there is evidence that the continued increase in lung volumes when they stop growing is due to a 'muscularity effect'. Boys generate larger pressures than girls at all lung volumes. Thus boys attain a larger TLC, and in spite of narrower airways, the same peak expiratory flow and a larger FIV1/FVC ratio than girls. Effort independent flows (FEV1 and MMEF), however, are larger in girls.