Cardiopulmonary function at rest and during exercise after resection for bronchial carcinoma

BACKGROUND: Measurements of postoperative spirometric values after pneumonectomy and lobectomy vary considerably, and few researchers have studied the changes in exercise capacity during maximal work after lung resection. The purpose of this study was to describe the postoperative alterations in cardiopulmonary function. METHODS: Ninety-seven consecutive patients with lung malignancy were prospectively examined with maximal exercise test, spirometry, and arterial gas tensions. Fifty-seven patients were reinvestigated 6 months postoperatively. RESULTS: In patients having lobectomy, forced expiratory volume in 1 second decreased 8%, and exercise capacity, expressed by maximal oxygen uptake and maximal work rate, significantly decreased 13%. In patients having pneumonectomy forced expiratory volume in 1 second significantly decreased 23%, but the loss in lung volume was partly compensated as measured by exercise capacity, which decreased only 16%. Generally patients with the smallest preoperative forced vital capacity had the smallest postoperative deterioration expressed in percentages. We found a weak correlation between alterations in maximal oxygen uptake and lung function after resection. CONCLUSIONS: Lobectomy is associated with only minor deterioration of lung function and exercise capacity. Pneumonectomy causes a decrease in pulmonary volumes to about 75% of the preoperative values, partly compensated in better oxygen uptake, which postoperatively was about 85% of the preoperative values. Alteration in forced expiratory volume in 1 second is a poor predictor of change in exercise capacity after pulmonary resection.     

Right ventricular ejection fraction in the preoperative risk evaluation of candidates for pulmonary resection

The major determinants of postoperative morbidity and mortality after lung resection are the physiologic and functional statuses of the pulmonary and cardiac systems. In our previous study, serial measurements of right ventricular performance after pulmonary resection demonstrated significant right ventricular dysfunction in the postoperative period. This study evaluates the preoperative measurement of right ventricular ejection fraction as a predictor of postoperative complications. In addition to conventional cardiopulmonary functional tests, right ventricular function was assessed with a thermodilution technique at rest and during exercise in 18 patients before and 3 weeks after lobectomy or pneumonectomy. The patients were grouped according to severity of right ventricular functional defect: right ventricular ejection fraction of at least 45% (group Ia, n = 8), right ventricular ejection fraction less than 45% (group Ib, n = 10), exercise-induced increases in right ventricular ejection fraction (group IIa, n = 8), and exercise-induced decreases in right ventricular ejection fraction (group IIb, n = 10). Postoperative cardiopulmonary morbidity was recorded for two patients (25%) in group Ia, three patients (30%) in group Ib, no patients (0%) in group IIa, and five patients (50%) in group IIb. Postoperative hospital stay was 28.9 +/- 8.5 days in group Ia, 29.9 +/- 20.2 days in group Ib, 19.4 +/- 8.0 days in group IIa, and 37.5 +/- 15.9 days in group IIb (p < 0.05, group IIa vs group IIb). Although resection-induced changes in forced expiratory volume in 1 second did not differ significantly between group Ia and group Ib, these values appeared to be increased in groups IIa (not statistically significant) and IIb (significantly, p < 0.05). The measured postoperative values of forced expiratory volume in 1 second and vital capacity were significantly higher than the predicted postoperative values (p < 0.05) in group IIa, but not in groups Ia, Ib, and IIb. We conclude that evaluation of right ventricular performance is useful in determining which patients are at increased risk for medical complications after lung resection. Exercise-induced change in right ventricular ejection fraction may be a better indicator of high risk among candidates for pulmonary resection than the absolute value of this parameter.     

Antibodies to prothrombin crossreact with plasminogen in patients developing myocardial infarction

This study aimed to determine the differences in haemodynamic responses to a standard incremental exercise test between outpatients with chronic obstructive pulmonary disease (COPD) and age-matched controls and to discover the relationship between severity of airflow obstruction and exercise haemodynamics in COPD. Twenty-two male patients with COPD (forced expiratory volume in one second (FEV1)/vital capacity (VC))<80% predicted) and 20 age-matched male controls performed an incremental exercise test (10 W x min(-1)) with ventilatory function and changes in stroke volume (deltaSV) and cardiac output (deltaCO) measured by means of electrical impedance cardiography (EIC). Submaximal deltaSV and deltaCO were lower in COPD patients. Peak exercise deltaSV were equal in patients and controls (128+/-33 versus 129+/-29%, p=0.98), whereas peak deltaCO was lower in patients (COPD versus controls: 232+/-71 versus 289+/-54%, p<0.005). In COPD patients, FEV1 (% pred) was significantly correlated to deltaSV at all submaximal exercise intensities, to peak exercise deltaSV and to peak exercise deltaCO. FEV1/VC (% pred) was significantly correlated to deltaSV at 30 and 60 W. In conclusion, in chronic obstructive pulmonary disease an aberrant haemodynamic response to exercise was found, especially in patients with severe airflow obstruction. This aberrant response is related to the degree of airflow obstruction and may limit exercise performance in patients with severe chronic obstructive pulmonary disease.     

Postoperative lung injury and oxidative damage in patients undergoing pulmonary resection

Postpneumonectomy pulmonary oedema (PPO) complicates a significant number of thoracic surgical procedures involving lung resection and in its extreme form is indistinguishable from the acute respiratory distress syndrome. This study investigated the possibility that ischaemia-reperfusion (I-R) injury contributes to PPO via the production of damaging reactive oxygen species. In a prospective, observational, comparative study, patients undergoing pneumonectomy, lobectomy, or wedge resection or open lung biopsy were investigated for perioperative changes in lung function indicative of lung injury and changes in plasma indices of oxidative damage. Significant percentage perioperative falls in plasma protein thiol levels (-17.9+/-7.0% for pneumonectomy, -24.3+/-5.5% for two-lobe lobectomy and -10.2+/-2.2% for one-lobe lobectomy, p<0.05) and rises in plasma protein carbonyl levels (26.2+/-10.5% for pneumonectomy, p<0.05, 9.8+/-7.0% for two-lobe lobectomy and 5.0+/-2.7% for one-lobe lobectomy) were identified, but not in patients undergoing biopsy or wedge resection. Plasma myeloperoxidase levels rose in all groups, but not significantly. The carbon monoxide transfer coefficient (K(CO)) fell significantly in patients undergoing lobectomy (p<0.05) but not in those undergoing wedge resection, lung biopsy or pneumonectomy. Changes in markers of oxidative protein damage occurred in patients undergoing lung resection, although the gas transfer coefficient fell significantly only following lobectomy. Oxidative damage occurs during pulmonary resection, although associated effects on gas exchange are seen only after lobectomy.     

Prediction of postoperative pulmonary hemodynamics for the second lobectomy after the contralateral lobectomy

We presented 7 cases who were performed the second lobectomy for the second lung cancer after the first successful lobectomy on the contralateral lung (3 cases for right upper lobectomy + left lower lobectomy and 4 cases for right upper lobectomy + left lower lobectomy). In 6 patients, the predicted postoperative FEV1 estimated by multiplying the preoperative FEV1 by the fraction of perfusion to the contralateral lung was less than 800 ml/m2BSA, which is our first cut-off for identifying lung resection candidates. Unilateral pulmonary arterial occlusion test (UPAO) revealed that total pulmonary vascular resistance (TPVRI) in 3 of those 6 patients was lower than 700 dyne.sec.cm-5/m2BSA, our second cut-off for lung resection. More precise postlobectomy pulmonary hemodynamics in another 3 of those 6 patients were then estimated by adapting selective pulmonary occlusion test (SPAO). Since TPVRI during SPAO was lower than the cut-off value, it was suggested that second lobectomy would be feasible with low incidence of post operative cardiopulmonary complication. There was no serious complications in all 7 cases during their postoperative course. We believe that more precise prediction of postoperative pulmonary hemodynamics by adapting UPAO and SPAO could be one of the tools to minimumize postoperative cardiopulmonary complications in those patients needed second lobectomy for the second lung cancer after the first successful lobectomy on the contralateral lung even though their impaired lung fung function.     

A prospective algorithm for the management of air leaks after pulmonary resection

BACKGROUND: Air leaks (ALs) are a common complication after pulmonary resection, yet there is no consensus on their management. METHODS: An algorithm for the management of chest tubes (CT) and ALs was applied prospectively to 101 consecutive patients who underwent elective pulmonary resection. Air leaks were graded daily as forced expiratory only, expiratory only, inspiratory only, or continuous. All CTs were kept on 20 cm of suction until postoperative day 2 and were then converted to water seal. On postoperative day 3, if both a pneumothorax and AL were present, the CT was placed to 10 cm H2O of suction. If a pneumothorax was present without an AL, the CT was returned to 20 cm H2O of suction. Air leaks that persisted after postoperative day 7 were treated with talc slurry. RESULTS: There were 101 patients (67 men); on postoperative day 1, 26 had ALs and all were expiratory only. Univariable analysis showed a low ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) (p = 0.005), increased age (p = 0.007), increased ratio of residual volume to total lung capacity (RV/TLC) (p = 0.04), increased RV (p = 0.02), and an increased functional residual capacity (FRC) (p = 0.02) to predict the presence of an AL on postoperative day 1. By postoperative day 2, 22 patients had expiratory ALs. After 12 hours of water seal, 13 of the 22 patients' ALs had stopped, and 3 more sealed by the morning of postoperative day 3. However, 2 of the 6 patients whose ALs continued experienced a pneumothorax. Five of the 6 patients with ALs on postoperative day 4 still had ALs on postoperative day 7, and all were treated by talc slurry through the CT. All ALs resolved within 24 hours after talc slurry. CONCLUSIONS: Most ALs after pulmonary resection are expiratory only. A low FEV1/FVC ratio, increased age, increased RV/TLC ratio, increased RV, and an increased FRC were predictors of having an ALs on postoperative day 1. Conversion from suction to water seal is an effective way of sealing expiratory AL, and pneumothorax is rare. If an expiratory AL does not stop by postoperative day 4 it will probably persist until postoperative day 7, and talc slurry may be an effective treatment.     

Long-term therapy of alpha 1-antitrypsin-deficiency-associated pulmonary emphysema with human alpha 1-antitrypsin

alpha 1-antitrypsin (alpha 1-AT) deficiency is a genetic disorder characterized by low serum levels of alpha 1-AT and a high risk of pulmonary emphysema at a young age. The resulting surplus of proteases, mainly of neutrophil elastase, can be balanced by i.v. augmentation with alpha 1-AT. However, it is not clear if affected patients benefit from long-term augmentation therapy and no long-term safety data are available. We examined 443 patients with severe alpha 1-AT deficiency and pulmonary emphysema receiving weekly i.v. infusions of 60 mg/kg body weight alpha 1-AT in addition to their regular medication. The progression of the disease was assessed by repeated lung function measurements, particularly the decline in forced expiratory volume in 1 second (delta FEV1). 443 patients with alpha 1-AT deficiency tolerated augmentation therapy well with few adverse reactions. The delta FEV1 in 287 patients with available follow-up data was 57.1 +/- 31.1 ml per year. Stratified for baseline FEV1, the decline was 35.6 +/- 21.3 ml in the 108 patients with an initial FEV1 < 30% and 64.0 +/- 26.4 ml in the 164 with 30% < FEV1 < or = 65% of predicted normal (p = 0.0008). The remaining 15 patients had an initial FEV1 > 65%. Long-term treatment with i.v. alpha 1-antitrypsin in patients with severe alpha 1-Pi deficiency is feasible and safe. The decline in forced expiratory volume in one second is related to the initial forced expiratory volume in one second as in alpha 1-antitrypsin deficient patients not receiving augmentation therapy.     

Lung diffusing capacity and exercise in subjects with previous high altitude pulmonary oedema

Subjects with a history of high-altitude pulmonary oedema (HAPE) have increased pulmonary artery pressure and more ventilation-perfusion (V'A/Q') inhomogeneity with hypoxia and exercise. We used noninvasive methods to determine whether there are differences in the pulmonary diffusing capacity for carbon monoxide (DL,CO) and cardiac output (Q') during exercise, indicative of a more restricted pulmonary vascular bed in subjects with a history of HAPE. Eight subjects with radiographically documented HAPE and five controls with good altitude tolerance had standard pulmonary function testing and were studied during exercise at 30 and 50% of normoxic maximal oxygen consumption (V'O2) at an inspiratory oxygen fraction of 0.14 and 0.21. DL,CO and Q' were measured by CO and acetylene rebreathing techniques. HAPE-resistant subjects had 35% greater functional residual capacity than HAPE-susceptible subjects. Vital capacity and total lung capacity were also 7-10% greater. There were no differences in airflow rates or resting diffusing capacity. However, DL,CO in HAPE-susceptible subjects was lower in hypoxia and with exercise, and showed less increase (32 versus 49%) with the combined stimulus of hypoxic exercise. HAPE-susceptible subjects had smaller increases in stroke volume, Q', and ventilation during exercise. The findings are consistent with lower pulmonary vasoconstriction, greater vascular capacitance and greater ventilatory responsiveness during exercise in subjects who are resistant to high-altitude pulmonary oedema. Their larger lung volumes suggest a constitutional difference in pulmonary parenchyma or vasculature, which may be a determinant of high-altitude pulmonary oedema resistance.     

Pulmonary function following laparoscopic or conventional colorectal resection: a randomized controlled evaluation

BACKGROUND: Laparotomy causes a significant reduction of pulmonary function, and atelectasis and pneumonia occur after elective conventional colorectal resections. OBJECTIVE: To evaluate the hypothesis that pulmonary function is less restricted after laparoscopic than after conventional colorectal resection. DESIGN: A randomized clinical trial. SETTING: The surgical department of an academic medical center. PATIENTS: Sixty patients underwent laparoscopic (n = 30) or conventional (n = 30) resection of colorectal tumors. The 2 groups did not differ significantly in age, sex, localization or stage of tumor, or preoperative pulmonary function. MAIN OUTCOME MEASURES: Forced vital capacity, forced expiratory volume in 1 second, peak expiratory flow, mid-expiratory phase of forced expiratory flow, and oxygen saturation of arterial blood. RESULTS: The forced vital capacity (mean +/- SD values: conventional resection group, 1.73+/-0.60 L; laparoscopic surgery group, 2.59+/-1.11 L; P<.01) and the forced expiratory volume in 1 second (conventional resection group, 1.19+/-0.51 L/s; laparoscopic surgery group, 1.80+/-0.80 L/s; P<.01) were more profoundly suppressed in the patients having conventional resection than in those having laparoscopic surgery. Similar results were found for the peak expiratory flow (conventional resection group, 2.51+/-1.37 L/s; laparoscopic resection group, 3.60+/-2.22 L/s; P<.05) and the midexpiratory phase of forced expiratory flow (conventional resection group, 1.87+/-1.12 L/s; laparoscopic surgery group, 2.67+/-1.76 L/s; P<.05). The oxygen saturation of arterial blood, measured while the patients were breathing room air, was lower after conventional than after laparoscopic resections (P<.01). The recovery of the forced vital capacity and forced expiratory volume in 1 second to 80% of the preoperative value took longer in patients having conventional resection than in those having laparoscopic resection (P<.01). Pneumonia developed in 2 patients having conventional resection, but no pulmonary infection occurred in the laparoscopic resection group (P>.05). CONCLUSIONS: Pulmonary function is better preserved after laparoscopic than after conventional colorectal resection. Pulmonary complications may be reduced after laparoscopic resections because of the better postoperative pulmonary function.     

Functional outcome of patients with chronic obstructive pulmonary disease and exercise hypercapnia

Chronic hypercapnia is associated with a poor prognosis in chronic obstructive pulmonary disease (COPD). Some patients are normocapnic at rest but retain CO2 during exercise. The significance of this abnormality on the course of the disease is unknown. Sixteen stable COPD patients (13 males and 3 females, aged 60 +/- 5 yrs, mean +/- SD) who had previously undergone pulmonary function tests and progressive exercise testing with arterial blood sampling at rest and maximal capacity, entered the study. At first evaluation (E1), subjects were normocapnic at rest (arterial carbon dioxide tension (Pa,CO2): 4.9-5.7 kPa, (37-43 mmHg)) and all presented exercise-induced hypercapnia (end-exercise Pa,CO2 > 5.7 kPa (43 mmHg) with a minimal 0.5 kPa (4 mmHg) increase from resting value). The subjects were re-evaluated 24-54 months later (34 +/- 8 months) (second evaluation (E2)). At E2, forced expiratory volume in one second (FEV1) had decreased from 42 +/- 13 to 38 +/- 15% of predicted values, and mean resting Pa,CO2 had increased from 5.2 +/- 0.3 to 5.7 + 0.4 kPa. Maximal exercise capacity (Wmax) decreased between E1 and E2 from 76 +/- 30 to 56 +/- 22 W. Even if Wmax was lower at E2, end-exercise, Pa,CO2 was higher than at E1 (6.6 +/- 0.8 vs 6.4 +/- 0.5 kPa). At E2, eight subjects presented resting hypercapnia (group H), whilst the others remained normocapnic (Group N). Group H subjects had higher Pa,CO2, at Wmax than Group N and lower Wmax than Group N at E2.(ABSTRACT TRUNCATED AT 250 WORDS)     

Biochemical disease-free survival following 125I prostate implantation

OBJECTIVES: The purpose of our study was to validate the incentive spirometry (IS) as a simple mean to follow pulmonary function at the bedside after lung surgery. MATERIALS AND METHODS: We studied prospectively 19 patients (16 men, 3 women; mean +/- SE age, 60 +/- 2.8 years) undergoing lobectomy for lung cancer. All the patients had an obstructive pattern with FEV1/FVC below 75%. Lung volumes, including functional residual capacity (FRC) and residual volume (RV), measured using spirometry and the helium dilution technique, and IS were measured preoperatively and postoperatively at days 1, 2, 3, and 8, and at 2 months. RESULTS: Our results showed that in the postoperative period after lung resection, IS performance was well correlated (R) during the first 8 postoperative days with vital capacity (VC) (R between 0.667 and 0.870) mainly due to the excellent correlation with the inspiratory reserve volume (IRV, R between 0.680 and 0.895) but was poorly correlated with expiratory reserve volume (R below 0.340), RV (R below 0.180), and FRC (R below 0.470). CONCLUSIONS: IS can be used as a simple mean to follow lung function, especially VC and IRV, in the postoperative period in spontaneously breathing patients. IS is noninvasive and can be performed repeatedly at the bedside in the intensive care setting.     

Thoracoscopic bilateral lung volume reduction for diffuse pulmonary emphysema

OBJECTIVE: In a prospective study, we investigated the functional results, complications and survival of bilateral video-assisted thoracoscopic (VAT) lung volume reduction (LVR) in a selected group of patients with severe, nonbullous pulmonary emphysema. From January 1994 to September 1996, 42 of 143 candidates (13 female, 29 male, 42-78 years) were operated. They were short of breath on minimal exertion due to severe airflow obstruction and hyperinflation (FEV1 < 30%) pred., TLC > 130% pred., RV > 200% pred.). METHODS: LVR was performed bilaterally by VAT using endoscopic staplers without buttressing the staple lines. Pulmonary function test (PFT), MRC dyspnea score and 12 min walking distance were assessed preoperatively, at 3, 6 and 12 months. In addition lung function was measured at hospital discharge. RESULTS: The patients reported a marked relief of dyspnea, which persisted at all follow-up visits (P<0.001). FEV1 increased from 0.80 +/- 0.24 (L) to 1.14 +/- 0.41 (L) postoperatively, a 43% gain (P < 0.001). A relevant increase of FEV1 persisted for at least 1 year. The residual volume to total lung capacity ratio decreased from 0.64 to 0.56 at hospital discharge. The mean 12 min walking distance increased from 500 +/- 195 (m) to 770 +/- 222 (m) after 1 year (P < 0.001). The mean hospital stay was 13 +/- 5.5 days (median 12.0), drainage time was 9 +/- 4.3 (median 8.0) days. There was no 30 day mortality. Three patients died between 2 and 15 months postoperatively by non surgery related reasons. One patient underwent lung transplantation 5 months after surgical lung volume reduction. CONCLUSIONS: In a selected group of patients with severe, nonbullous pulmonary emphysema, bilateral LVR by VAT results in instantaneous postoperative improvement in pulmonary function and dyspnea. These favorable effects, including an amelioriation in exercise performance, lasted for at least 1 year.     

Inability to perform bicycle ergometry predicts increased morbidity and mortality after lung resection

The ability to successfully exercise has been used to assess the cardiopulmonary risk of thoracotomy for lung cancer. Because of musculoskeletal, neurologic, peripheral vascular, or behavioral problems, not all patients presenting for pulmonary resection are capable of exercising. Using a multifactorial cardiopulmonary risk index (CPRI) consisting of a cardiac risk index (CRI) and a pulmonary risk index, we studied 74 patients (60 capable of exercising and 14 incapable of exercising) who underwent thoracotomy for lung cancer resection. The groups were similar in reference to history of pulmonary disease, preoperative pulmonary function, and pulmonary risk index score. The no-exercise patients were more likely to have a history of cardiac disease (64 vs 28%; p < 0.01) and had a higher CRI score (2.0 +/- 0.2 vs 1.4 +/- 0.1; p < 0.05). Cardiopulmonary postoperative complications (POCs) and mortality were more likely among those in the no-exercise group vs those in the exercise group (POCs, 79 vs 35%, p < 0.01; mortality, 21 vs 2%, p < 0.05). Among the eight no-exercise patients with a CPRI of 4 or more, all eight suffered a POC (100%) and three died (38%). Using multiple logistic regression analysis, both the CPRI score and the inability to exercise were independently associated with increased risk for POCs. We conclude that patients unable to perform even minimal preoperative exercise are at substantially increased risk for morbidity and mortality after lung resection. This results both from greater identifiable preoperative cardiopulmonary risk factors (as assessed by the CPRI) and from an independent effect related to the inability to exercise.     

Delayed pulmonary toxicity syndrome following high-dose chemotherapy and bone marrow transplantation for breast cancer

We have intensely followed 45 consecutive women who underwent high-dose chemotherapy (cyclophosphamide/cisplatin/BCNU) and autologous bone marrow transplant (HDC/ABMT) for primary breast cancer with pulmonary function testing and computed tomography at regular intervals up to 126 wk (median follow-up, 72 wk). Our results show a high incidence of interstitial pneumonitis requiring steroids (64%), but no deaths due to pulmonary toxicity. The DL(CO) reaches a nadir of 58.2 +/- SEM 3.4 (expressed as a percent of baseline value) 15-18 wk following HDC/ABMT, and marginally improves with time. To a much lesser extent, vital capacity is reduced with a parallel drop in FEV1, suggesting mild restrictive changes without significant obstruction. Patients who develop pulmonary symptoms of cough or dyspnea have a corresponding significantly greater and earlier decline in DL(CO). Chest computed tomography was neither sensitive nor specific for diagnosing pulmonary toxicity. For patients who received steroids for pulmonary toxicity, there was a subsequent improvement in DL(CO) of 17.1% (p = 0.0001). Because our patients do not fit with the recent definition of idiopathic pulmonary syndrome (IPS), we propose the term delayed pulmonary toxicity syndrome (DPTS) to better describe the milder form of lung toxicity seen in our patient population. We were unable to correlate the severity of DPTS with age, tobacco use, baseline pulmonary function, or systemic exposure to BCNU, cyclophosphamide, or cisplatin. These data suggest that factor(s) other than, or in addition to, chemotherapy systemic exposure can contribute to DPTS. Furthermore, early identification and institution of systemic corticosteroids may improve lung function.     

Prediction of exercise capacity after lung resection in patients with chronic airflow limitation

To assess the usefulness of a method for predicting postoperative peak oxygen uptake based on lost lung function after lung resection (VO2peak-PPO) and to establish the underlying physiological foundation for the relation between VO2peak-PPO and the measured postoperative value VO2peak-PO), we studied 29 patients (26 men) [age 60 (SD9)] with chronic airflow limitation [FEV1 = 66 (SD13)%] undergoing lobectomy or major pulmonary resection to treat lung cancer. The patients were assigned to groups according to whether postoperative exercise tolerance was considered to be limited by exhaustion of ventilatory reserve (LV) or not (NLV). Data to estimate postoperative pulmonary function was obtained one week before surgery: patients performed pulmonary function tests and exercise tests on a treadmill; dyspnea was also evaluated and perfusion scintigraphs were obtained. Pulmonary function, exercise tolerance and dyspnea were evaluated again approximately five months after surgery. The mean difference between VO2peak-PPO and VO2peak-PO was -0.034 (CI 0.293 to -0.348) l.min-1 and the between-group correlation coefficient was 0.76. The correlation between VO2peak-PPO and VO2peak-PO was 0.86 (SE 0.1) [0.89 (SE 0.13) for LV (n = 14) patients and 0.85 (SE 0.16) for NLV (n = 15) patients]. The correlations after adjusting for preoperative VO2peak-PPO were 0.73 (SE 0.2) and 0.35 (SE 0.27) for LV and NLV patients, respectively. We conclude that VO2peak-PPO provides a valid but only moderately precise estimate of VO2peak-PO. Only in LV patients is there a true relation between a decrease in VO2peak and loss of lung function.     

Micronodules and emphysema in coal mine dust or silica exposure: relation with lung function

The aim of this study was to investigate the respective effects of micronodules and pulmonary emphysema, detected by computed tomography (CT), on lung function in workers exposed to silica and coal mine dust. Eighty-three subjects exposed to silica (n=35) or to coal mine dust (n=48), without progressive massive fibrosis, were investigated by high-resolution and conventional CT scans to detect micronodules and to quantify pulmonary emphysema by measuring the relative area of the lung with attenuation values lower than -950 Hounsfield units. Sixty-six (54.5%) subjects had evidence of micronodules on CT scans. Smokers had micronodules more rarely than nonsmokers. Significant correlations were found between the forced expiratory volume in one second (FEV(1); % predicted) (r=-0.41, p<0.001), FEV1/vital capacity (VC) (r=-0.61, p<0.001), diffusing capacity of the lung for carbon monoxide (DL,CO) (r=-0.36, p<0.001) and the extent of emphysema. No difference was demonstrated in the linear relationships between the extent of emphysema and the pulmonary function according to the type of exposure or the presence of micronodules on CT scans. This study suggests that micronodules detected by computed tomography have no influence, by themselves, on pulmonary function and that they should only be considered as a marker of exposure.     

Relationship between external resistances, lung function changes and maximal exercise capacity

In upper airway obstruction (UAO) the relationship between the degree of obstruction, exercise limitation and lung function indices is not well established. Therefore, we investigated in nine healthy subjects (age 36+/-9 yrs) the effects of two added resistances at the mouth (R1 = added resistance with 7.8 mm diameter; R2 = 5.7 mm) on forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), airway resistance (Raw) and maximal breathing capacity (measured during 15 s = measured maximum breathing capacity (MBCm); calculated as FEV1x37.5 = calculated maximum breathing capacity (MBCc)) on the one hand, and maximum exercise capacity (W'max), minute ventilation (V'E) and CO2 elimination (V'CO2) on the other. We found that R1 had almost no influence on FEV1 but decreased PEF by approximately 35% and increased Raw by almost 300%; it decreased W'max by merely approximately 10% while maximal exercise ventilation (V'Emax) was only 65% of control and only reached approximately 40% MBCc and approximately 70% MBCm; yet V'E and V'CO2 were significantly reduced at high exercise levels indicating hypoventilation. With R2, FEV1 was reduced by 25% and PEF by 55%, and Raw was increased by 600%; W'max was approximately 60% of control, V'Emax was only 35% of control and reached approximately 30% MBCc and approximately 60% MBCm, V'E was already reduced at moderate exercise levels. We conclude that: 1) an upper airway obstruction of 6 mm diameter (but not of 8 mm) had a marked influence on maximum exercise capacity due to hypoventilation; 2) calculated maximum breathing capacity markedly overestimated measured maximum breathing capacity because the forced expiratory volume in one second is an insensitive index of upper airway obstruction and because it does not take inspiratory flow limitation into account; and 3) a 10% decrease in maximum exercise capacity was linearly related with a 7% decrease in the forced expiratory volume in one second and a 150% increase in airway resistance. A 10% decrease in maximal exercise ventilation was related to a 8.5% decrease in peak expiratory flow and 9% decrease in measured maximum breathing capacity.     

Relation between preoperative inspiratory lung resistance and the outcome of lung-volume-reduction surgery for emphysema

BACKGROUND: Surgery to reduce lung volume has recently been reintroduced to alleviate dyspnea and improve exercise tolerance in selected patients with emphysema. A reliable means of identifying patients who are likely to benefit from this surgery is needed. METHODS: We measured lung resistance during inspiration, static recoil pressure at total lung capacity, static lung compliance, expiratory flow rates, and lung volumes in 29 patients with chronic obstructive lung disease before lung-volume-reduction surgery. The changes in the forced expiratory volume in one second (FEV1) six months after surgery were related to the preoperatively determined physiologic measures. A response to surgery was defined as an increase in the FEV1 of at least 0.2 liter and of at least 12 percent above base-line values. RESULTS: Of the 29 patients, 23 had some improvement in FEV1 including 15 who met the criteria for a response to surgery. Among the variables considered, only preoperative lung resistance during inspiration predicted changes in expiratory flow rates after surgery. Inspiratory lung resistance correlated significantly and inversely with improvement in FEV1 after surgery (r=-0.63, P<0.001). A preoperative criterion of an inspiratory resistance of 10 cm of water per liter per second had a sensitivity of 88 percent (14 of 16 patients) and a specificity of 92 percent (12 of 13 patients) in identifying patients who were likely to have a response to surgery. CONCLUSIONS: Preoperative lung resistance during inspiration appears to be a useful measure for selecting patients with emphysema for lung-volume-reduction surgery.     

Amperometric lactate oxidase catheter for real-time lactate monitoring based on thin film technology

Electronic spirometry units were used to monitor lung transplantation recipients upon their return home. The data from 77 participants were used to develop methods to verify that the pulmonary function measurements, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), were reliable and valid. The standard deviation was calculated for the best daily effort on consecutive days of home spirometry. An acceptable upper limit for the standard deviation, as the measure of day-to-day reliability, was 0.20 for FVC and 0.15 for FEV1. Validity was determined by examining the mean difference (bias) between the spirometry done in the pulmonary function laboratory and the home monitoring results. The clinic values were slightly higher, with an average difference of 0.15 for FVC and 0.12 for FEV1. Therefore, the home spirometry measurements have a high degree of reliability and validity and can now be used for early detection of serious complications.