Effect of age on changes in flow rates and airway conductance after a deep breath

The effects of aging on changes in maximal expiratory flow rates and specific airway conductance after a deep breath were evaluated in 64 normal subjects. Flow rates (Vp) on partial expiratory flow-volume curves (PEFV), initiated from 60-70% of the vital capacity (VC), were compared with those (Vc) on maximal flow-volume curves (MEFV), initiated from total lung capacity (TLC), at a lung volume corresponding to 25% of VC on the MEFV curves. Specific airway conductance was measured before (sGaw) and after a deep inspiration (sGawDI). Bronchodilation after inspiration to TLC was inferred by Vp/Vc less than 1 and sGaw/sGawDI less than 1. The mean Vp was less than Vc. However, the ratio Vp/Vc increased significantly with age (r = 0.75, P less than 0.001). Specific conductance also increased after a deep inspiration (sGaw less than sGawDI). The ratio sGaw/sGawDIj increased slightly but significantly with age (r = 0.28, P less than 0.02). Measurement of lung elastic recoil pressures before and after a deep breath in a subgroup of patients (n = 14) suggested that the age-related increase in Vp/Vc was secondary to a decrement in the ability of a deep breath to decrease the upstream airway resistance. These findings suggest that even though changes in airway size after a deep breath as measured by sGaw/sGawDI have minimal age dependence, aging diminishes expiratory flow rates of MEFV curves relative to PEFV curves because of a decrease in the ability of a deep breath to increase the size of the peripheral airways.

Long-term survival of a lung cancer patient treated with photodynamic therapy

A 63-year-old male, status post-right pneumonectomy, presented with hemoptysis. Although chest X-ray and CAT scan film findings were negative, bronchoscopy with biopsy from the left mainstem bronchus demonstrated squamous cell carcinoma. Because of the inoperable location of the lesion, the patient was treated with photodynamic therapy (PDT) in February 1984. At present, the patient is cancer free more then 6 years after PDT.

Effects of thoracic gas compression on maximal and partial flow-volume maneuvers

Airway hysteresis can be evaluated by comparing maximal (MEFV) and partial (PEFV) expiratory flow-volume curves. The maneuvers are often obtained from pulmonary function systems that are subject to gas-compression artifacts. Because gas-compression artifacts might differentially affect PEFV vs. MEFV curves, we simultaneously obtained MEFV and PEFV curves by use of a spirometer and a volume-displacement plethysmograph (a method not subject to gas-compression artifacts) in normal and asthmatic subjects. Plethysmographic flow rates exceeded spirometric flow rates on all MEFV and PEFV maneuvers. When maximal flow exceeded partial flow (or vice versa) in the plethysmograph, the same result was virtually always observed for spirometric measurements. Alveolar pressure (PA) was higher on MEFV than on PEFV maneuvers in asthmatic subjects; comparisons between PA (on PEFV and MEFV maneuvers) in normal subjects varied at different lung volumes. Ratios of Vmax on PEFV maneuvers to Vmax on MEFV maneuvers (Vmax-p/Vmax-c) obtained from a volume-displacement plethysmograph differ quantitatively from ratios determined in systems subject to gas-compression artifacts; qualitatively, however, failure to account for thoracic gas compression ordinarily will not influence the ability to identify airway hysteresis (or lack thereof) by use of Vmax-p-to-Vmax-c ratios.

The MVV/FEV1 ratio in normal and asthmatic subjects

We compared the ratio of maximal voluntary ventilation/forced expiratory volume in one second (MVV/FEV1) in normal individuals and asthmatic subjects. Our hypothesis was that MVV/FEV1 would be lower in asthmatic subjects. We also compared MVV/FEV1 results with the effects of deep inspiration (DI) on bronchomotor tone and with methacholine responsiveness. In normal subjects, MVV/FEV1 was higher than that in asthmatic subjects. Specific conductance (SGaw) increased after a single DI or an MVV maneuver in normal individuals. An MVV maneuver caused SGaw to decrease in asthmatic subjects. In asthmatic subjects, there was a significant correlation between MVV/FEV1 ratio and magnitude of decrease in SGaw after an MVV maneuver. Results of methacholine testing indicated that asthmatic subjects with low MVV/FEV1 ratios were more responsive to methacholine than those whose MVV/FEV1 ratios were within normal range. We conclude that MVV/FEV1 ratios are abnormally low in many asthmatic subjects and that low MVV/FEV1 ratios may indicate increased bronchial responsiveness to methacholine.

How much theophylline is enough?

Theophylline not only is a bronchodilator but also has other effects (inhibition of mediator release, enhancement of mucociliary clearance, enhancement of diaphragmatic contractility) that are potentially beneficial to asthmatic patients. Recent studies suggest that theophylline pharmacodynamics vary among asthmatic patients. However, on average, most of the total bronchodilatory response occurs at serum theophylline concentrations of 0 to 10 mg/liter. Additional (but less) bronchodilatation occurs at serum theophylline levels between 10 and 20 mg/liter. Pharmacodynamic relationships are not well established for other therapeutic effects of theophylline, such as attenuation of pharmacologically induced bronchoconstriction. An important feature of oral controlled-release theophylline therapy is timing of drug administration. Because airway reactivity increases and airway caliber decreases at night, it has been suggested that the greatest benefit is derived from theophylline when peak serum concentration is reached during the night or the early morning.

Effect of dimethylthiourea on plasma paraquat concentration

In a previous study, administration of the hydroxyl radical scavenger, dimethylthiourea (DMTU), and paraquat was associated with higher mortality in rats than was paraquat alone. In the present study, the possibility was evaluated that administration of DMTU increased plasma paraquat levels. Plasma paraquat concentrations were measured in Sprague-Dawley rats 1, 2, 4, 8 and 24 h after intraperitoneal (i.p.) injection of 29 mg paraquat cation/kg body wt. Another group of rats was treated identically except that they received i.p. injections of DMTU before injections of paraquat. Administration of DMTU was associated with increased plasma paraquat concentration (P less than 0.01). Pharmacokinetic analyses indicated that, compared to rats receiving paraquat alone, rats given paraquat and DMTU showed: (1) greater area under the paraquat concentration time-curve; (2) lower total body paraquat clearance; and (3) smaller apparent volume of distribution. Plasma biochemical studies indicated that paraquat caused hyperglycemia as well as an early reduction (compared to controls) in hepatic enzymes. We conclude that: (1) DMTU administration is associated with increased plasma paraquat concentrations; and (2) impaired synthesis or inhibition of release of hepatic proteins may be an early effect of paraquat.

Adverse effects of (15S)-15-methyl-prostaglandin E1 in normal and paraquat-exposed rats

Single, daily injections of approximately 1 mg/kg of (15S)-15-methyl-PGE1 (mPGE1), a PGE1 analog, have been reported to inhibit inflammation and to prolong survival in several animal models of local and systemic inflammation. We examined the effect of this dose of mPGE1 on paraquat toxicity in rats. A significant increase in early mortality was identified in mPGE1-treated rats as early as 3 hr following injection of paraquat and appeared associated with increased respiratory effort. Rats given mPGE1 without paraquat also appeared to increase respiratory effort but did not die. Rats killed at 3 hr following injections demonstrated increased lung weights in both paraquat-injected and control animals receiving mPGE1. Although a neutrophilia was identified in these animals, no significant increase in lung lavage neutrophils or albumin was identified. These data suggest that large intermittent doses of a PGE1 analog may adversely affect the respiratory system of normal and injured animals, and will accelerate mortality following exposure to potentially lethal doses of paraquat.

Effect of lung inhomogeneity on partial flow-volume manoeuvres

We evaluated the effects of inhomogeneous lung emptying on the relationship of partial to maximal complete expiratory flow by obtaining pre- and post-metaproterenol maximal (MEFV) and partial flow-volume curves in normal subjects and asthmatics. Partial curves were initiated between 65-70% of vital capacity after inspiration from functional residual capacity (PEFV curve) or after deflation from total lung capacity (PEFVDI curve). Since PEFVDI curves were initiated at lower lung volumes than MEFV manoeuvres (but with a similar volume history), non-homogeneous emptying should cause higher flow on PEFVDI than on MEFV manoeuvres. Expiratory flow (Vmax) was highest on MEFV manoeuvres in normals and PEFV curves in asthmatics. Pre- and post-metaproterenol Vmax was very similar on MEFV and PEFVDI manoeuvres in both groups, although Vmax(MEFV) slightly but significantly exceeded Vmax(PEFVDI) in normals and the reverse was true in asthmatics. Lung elastic recoil did not differ significantly on MEFV and PEFVDI manoeuvres in either group. We conclude that asthmatics demonstrate inhomogeneous emptying. However, because flow-volume curves are relatively insensitive to sequences of lung emptying, inhomogeneous emptying during forced expiration only has minor effects on the relationship of partial to maximal expiratory flow.

Pulmonary physiology in the postoperative period

After upper abdominal or thoracic surgery, loss of lung volume, manifested most importantly by reduced FRC, and abnormal gas exchange, manifested by postoperative reduction in PaO2, are the rule rather than the exception. These physiologic alterations in lung function occur in the absence of superimposed complications such as pneumonia and/or lobar atelectasis; the usual physiologic alterations do, in fact, predispose to pulmonary complications (approximate 20 per cent incidence) which, when present, further compromise lung function. The mechanisms of postoperative impairment in lung function are multiple, interactive, and at the present, incompletely understood. An attempt to summarize the more important causes of impaired postoperative lung function is shown in Figure 6.

Evaluation of a metered-dose aerosol delivery system using partial flow-volume curves

In 12 normal subjects, FEV1, FVC, peak expiratory flow rate, and flow at 25% of FVC on maximal (MEFV) and partial (PEFV) expiratory flow volume maneuvers were measured before and after inhalation of 2.6 mg of metaproterenol from a metered-dose inhaler (MDI) or from an MDI-holding chamber (MDI-HC) delivery system. The 2 delivery systems were studied on separate days using a randomized crossover design. Premetaproterenol pulmonary function results were very similar on both days. However, on the MDI-HC day, significantly greater bronchodilatation was observed; this was only detectable on PEFV maneuvers. Compared with those on the MDI day, postmetaproterenol PEFV rates on the MDI-HC day were approximately 11% higher (p less than 0.02); premetaproterenol to postmetaproterenol increments in PEFV rates were also larger on the MDI-HC day (p less than 0.05). These results can be explained by the phenomenon of airway hysteresis. The deep breath taken prior to performance of the FVC maneuver reduced bronchomotor tone in almost all subjects, thereby limiting the magnitude of possible change from inhaled bronchodilator. Partial flow-volume curves were not preceded by deep inspiration and were more sensitive in detecting bronchodilatation.

Relationships between minute ventilation, oxygen uptake, and time during incremental exercise

It has recently been reported that blood and muscle lactate increased exponentially during incremental exercise, casting some doubt upon the concept of 'anaerobic threshold'. To gain further insight into this controversy, we examined the relationships between minute ventilation (VE), time and oxygen uptake (VO2) in normal subjects during incremental exercise. During exercise, the relationship of VE to either time of exercise or to VO2 appeared curvilinear; VE was reliably described as an exponential function (y = axb + c) of both time of exercise (r2 = 0.96) and VO2 (r2 = 0.92). We also compared variables from 30-second incremental tests with variables obtained from quasi-steady-state incremental tests using cycle and treadmill ergometry. With the exception of heart rate, variables measured at maximum exercise were similar during short-duration and quasi-steady-state incremental tests. These data support the ideas that: there is no abrupt change in metabolism and oxygen availability during progressive exercise, and results of rapid incremental and quasi-steady-state exercise tests are generally comparable in normal individuals.

Time dependence of airways and lung parenchymal recoil hysteresis

Hysteresis of airways and lung parenchymal recoil was examined in normal subjects by measuring specific conductance (sGaw) and lung elastic recoil (Pst,L) before and 5, 10, 15, and 30 s after deep inspiration (DI). Routine lung function tests were normal before and after inhaled metaproterenol. sGaw increased significantly for 10 s after DI. Also, sGaw(DI) was greater than sGaw in 11 of 12, 8 of 12, 7 of 12, and 6 of 12 subjects at 5, 10, 15, and 30 s, respectively, after DI. The response of sGaw to DI and metaproterenol correlated significantly with each other (r = 0.82, P less than 0.001). However, after metaproterenol, sGaw(DI) did not exceed sGaw. Pst,L decreased significantly for 15 s after DI, with the lowest measured Pst,L(DI) values occurring 5 s after DI (P less than 0.01-0.001). Both sGaw(DI) and Pst,L(DI) values returned to base line (preinspiration) in a time-dependent exponential manner, with time constants of 9.2 +/- 4.9 and 11.3 +/- 6.1 s, respectively; these time constants were not significantly different from each other. We conclude that airways hysteresis is the predominant finding in normal subjects (even without prior pharmacological bronchoconstriction) before but not after metaproterenol; Pst,L decreases after DI and, in normal individuals, returns to base line in a time-dependent manner; and the time-dependent behavior of airways and lung parenchymal hysteresis have opposite (and unequal) effects on airway caliber.

The effects of paraquat dichloride on clinical chemistry measurements

Although measurements in the clinical chemistry laboratory are routinely used to monitor renal and hepatic toxicity from paraquat, it is not known if paraquat, a strong oxidant, interferes with common laboratory tests. The authors analyzed the effects of paraquat (concentration range of 0 to 1000 mg/L) on the Beckman IDEAL and Technicon SMAC analyzers for 20 common analytes. Although 18 tests were unaffected by paraquat, creatinine values rose from 1.3 to 7.6 mg/dL on the SMAC and 1.3 to 3.0 mg/dL on the IDEAL. Also, LDH was unaffected, rising by 6 and 12% on the IDEAL and the SMAC, respectively. Values for these correlated positively with serum paraquat concentrations although little effect could be discerned at paraquat levels less than or equal to 10 mg/L. Thus, the magnitude of the effects were such that interference by paraquat with the measurements of creatinine and LDH can be considered insignificant in clinical circumstances.

Supine change in arterial oxygenation in patients with chronic obstructive pulmonary disease

In normal subjects, recumbent PaO2 differs from upright PaO2 as a function of the relationship between FRC and closing volume. However, in patients with lung disease, the factors controlling PaO2 change. Furthermore, the distribution of airway closure does not strictly reflect gravitational gradients in pleural pressure. Hence, we evaluated the effects of recumbency on PaO2 in patients with advanced COPD. We conducted pulmonary function tests and measured PaO2, AaPO2, change from upright to supine FRC, VE, cardiac output (QT), and mixed venous oxygen saturation (SvO2). Eight patients with COPD in whom PaO2 decreased in the supine position (Group I) were compared with 8 patients with COPD in whom PaO2 improved in the recumbent position (Group II); the only anthropometric difference between the groups was greater body weight in Group II (p less than 0.05). Pulmonary function was comparable in the 2 groups. In both groups, FRC decreased with recumbency, but supine FRC and delta FRC did not differ between groups nor correlate significantly with PaO2, AaPO2, or venous admixture (QVA/QT). Supine SVO2 increased in both groups, but supine QT increased significantly only in Group I. In Group II, recumbent QVA/QT did not change significantly, whereas recumbent QVA/QT increased (p less than 0.02) in Group I. The cause for increased QVA/QT in Group I was reduced VE plus increased QT while supine; in contrast, by maintaining a higher supine VE and by not increasing QT significantly, an increase in QVA/QT was prevented in Group II subjects, an increase that would otherwise have overwhelmed the benefits of increased recumbent SVO2 on PaO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a deep inspiration on expiratory flow in normals and patients with chronic obstructive pulmonary disease

Normal control subjects and individuals with chronic obstructive pulmonary disease (COPD) were studied by measuring routine lung function tests as well as maximal (MEFV) and partial expiratory flow-volume (PEFV) curves and lung elastic recoil (Pst,L) before and after a total lung capacity (TLC) volume history. In the normal subjects: before bronchodilators airflow increased significantly, whereas Pst,L and upstream segment resistance (Rus) decreased significantly following inspiration to TLC; after administration of inhaled bronchodilators, flow rates were higher on the PEFV than on MEFV curves; nevertheless, because Pst,L decreased substantially following a deep breath, post-bronchodilator Rus was still somewhat reduced by deep inspiration. In the subjects with COPD flow rates on PEFV curves were as high or exceeded flow rates on MEFV curves in 76/100 studies; the ratio of flow rates (PEFV)/flow rates (MEFV) increased as pulmonary function worsened; as in normal subjects, Pst,L diminished in COPD subjects following deep inspiration; although flow rates increased on both PEFV and MEFV curves after bronchodilators, the increments in flow were considerably larger on PEFV maneuvers.

Comparison of once-a-day and twice-a-day theophylline in asthma

Sustained-release theophylline compounds given once (Uniphyl) or twice (Theodur) daily were compared in adult asthmatics. Following a single dose of oral medication, large and peripheral airways bronchodilation occurred; response to theophylline correlated significantly with the log plasma theophylline concentration. Cardiac output and stroke volume, measured noninvasively using the acetylene technique, also increased significantly. During maintenance therapy, both preparations caused similar improvements in pulmonary function and symptoms; however, side effects were less with once-daily therapy.

Comparison of clinical effects and pharmacokinetics of once-daily Uniphyl and twice-daily Theo-Dur in asthmatic patients

A pharmacokinetic study using theophylline syrup in adult asthmatic patients demonstrated a mean apparent volume of distribution of 0.38 liters/kg, mean elimination rate constant of 0.10 hours-1, and variable rates of clearance of theophylline (total body clearance of 0.38 to 0.96 ml/kg per minute). Subsequently, the asthmatic patients were compared using a cross-over design after maintenance Uniphyl (once daily at 8 a.m. or at 8 p.m.) and Theo-Dur (twice daily at 8 a.m. and 8 p.m.). Total daily maintenance theophylline dosage, calculated from the pharmacokinetic data, was identical in all three cross-over phases. At the end of each phase, plasma theophylline levels were measured every two hours and spirometric determinations were made every four hours (excluding 4 a.m.) for 24 hours. The following results were observed: highest peak and mean plasma theophylline concentration and area under the concentration-time curves with evening Uniphyl (p less than 0.05); prolonged time-to-peak theophylline concentration after nocturnal compared with daytime dosing; diurnal variation in pulmonary function and plasma theophylline concentrations; no significant differences between the three maintenance treatments in asthmatic symptoms or spirometric results.

Role of Alternaria and Penicillium spores in the pathogenesis of asthma

The ability to harvest spore-rich isolates of molds permitted quantitative studies of their role in the pathogenesis of asthma. Alternaria and Penicillium were selected as examples of ubiquitous molds that readily induce IgE antibodies and are of contrasting sizes. Extracts from those spores were prepared for skin tests and aerosol bronchial challenges. Intact spores were used in the same subjects in bronchial challenges delivered by a Spinhaler. Seven patients with a history of mild asthma received a total of 16 bronchial challenges with the mold to which they had been sensitized. Provocative doses in spore equivalents for a 35% drop in SGaw, 20% drop in FEV1, or 25% drop in PEFR were sought for each challenge. Density dependence-flow rates were also determined. Environmental spore survey data were obtained and compared with the challenge doses for these spores. It was found that immediate-type asthma was readily provoked by both whole spores and by their extracts, in some subjects fewer intact than extracted spores were required, delayed-type asthma occurred only after whole spore challenges, SGaw was the most sensitive and equally specific of the pulmonary function tests, and provocative doses of spore equivalents were within natural exposure ranges. The study confirmed that Alternaria and Penicillium spores in relatively natural states and numbers were potent immunopathogens for asthma.

Partial and maximal expiratory flow-volume curves in normal and asthmatic subjects before and after inhalation of metaproterenol

The effects of deep inspiration upon expiratory flow rates and response to inhaled metaproterenol were studied in normal and asthmatic subjects using partial (PEFV) and maximal (MEFV) expiratory flow volume curves. Routine pulmonary function tests and specific conductance were also measured. Prior to administration of metaproterenol, 18 of 24 normal subjects and 11 of 24 asthmatic subjects (p 0.05) had higher flow rates on MEFV than on PEFV curves. The 11 volume history responsive asthmatic subjects showed better lung function and more density-dependence of expiratory flow than the other 13 asthmatic subjects; furthermore, the effect of lung inflation was significantly larger in the volume history responsive asthmatic subjects than in the volume history responsive normal subjects. Responses to inhaled metaproterenol were much larger on PEFV than MEFV curves; nevertheless, differences between normal and asthmatic subjects in metaproterenol responsiveness were less using PEFV curves. Thus, the use of PEFV curve measurement did not facilitate the detection of individual asthmatic responses to inhaled metaproterenol.

Magnesium and potassium therapy in multifocal atrial tachycardia

Eight patients with multifocal atrial tachycardia received 7 to 12 gm of magnesium sulfate intravenously over a 5-hour period. Potassium supplements were given initially or added later. Initial arterial blood gases showed mean pH 7.48 +/- 0.03, PcO2 39.7 torr, PO2 72 torr, HCO-3 29.8 +/- 4.5 mEq/L, and base excess 6.84 +/- 3.78 mEq/L. Initial serum magnesium correlated well with initial serum potassium. Three patients had subnormal levels of magnesium and potassium. The level of serum magnesium rose with an intravenous injection magnesium and serum potassium levels tended to fall unless they were supplanted with potassium. There were seven patients who retained more than 20 mEq of the infused magnesium. Multifocal atrial tachycardia was successfully converted to sinus rhythm or sinus tachycardia in seven patients. Multifocal atrial rhythm (at slow rate) persisted in one patient. Two patients with falling serum potassium levels required potassium supplements. Results of this study confirm that patients with multifocal atrial tachycardia respond favorably to parenteral magnesium and potassium. We believe that serum magnesium administered together with serum potassium stabilizes the ionic balance of atrial cells and thus prevents spontaneous ectopy.

Hypoventilation in a case of nonfamilial Parkinson's disease

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Airway hysteresis in normal subjects and individuals with chronic airflow obstruction

Specific conductance (sGaw) was measured without prior pharmacological induction of bronchoconstriction before and 5-10 s after a total lung capacity (TLC) volume history in normal subjects and in individuals with chronic airflow obstruction (CAO); increased sGaw after inspiration to TLC was considered evidence of airway hysteresis. Lung elastic recoil [Pst(L)] was also measured before and after inspiration to TLC. In the normal subjects 1) prebronchodilator sGaw increased significantly, whereas Pst(L) decreased significantly after inspiration to TLC; 2) modulators of cyclooxygenase activity had no significant effects on sGaw responses to deep inspiration; and 3) airway hysteresis diminished after inhalation of atropine or metaproterenol. In the CAO group 1) prebronchodilator sGaw and Pst(L) decreased significantly after inspiration to TLC, and 2) bronchoconstriction after deep inspiration diminished after inhalation of atropine or metaproterenol. This study demonstrates that normal airways exhibit hysteresis even without alteration of resting airway tone and that airway hysteresis is impaired in CAO.

Pulmonary pathology in renal transplant recipients

Studies of the lungs have revealed multiple functional and histopathological abnormalities in patients with chronic renal failure, but data following renal transplantation are extremely limited. We examined postmortem data from 20 transplant patients and found pulmonary abnormalities in most patients. The number of pulmonary abnormalities noted in patients with poor transplantation, averaged 5.3 per patient. The corresponding number was significantly less (3.4 per patient) in the group with good transplant renal function, surviving more than one year after transplantation. Pulmonary calcification, fibrosis, and hemosiderosis were found in several patients in the former group but in none of the latter group. This observation suggests reversibility of these pulmonary abnormalities with successful renal transplantation.

Effect of dimethylthiourea on paraquat toxicity in rats

We evaluated the utility of dimethylthiourea ( DMTU ), a hydroxyl radical scavenger, as potential therapy for paraquat poisoning. Seventy-five male Sprague-Dawley rats were divided into four groups ( DMTU -paraquat, paraquat, DMTU , control) and studied for up to 10 days. Clinical observations (dyspnea, weakness), mortality, hepatic and renal function tests, body weights, and histologic studies were performed. There was no mortality in the DMTU and control groups although various histologic and biochemical studies suggested that DMTU may be both hepatotoxic and nephrotoxic. In contrast, 74% of DMTU -paraquat rats and 39% of paraquat rats died (p less than 0.01). In addition, toxicity was clearly earlier in the DMTU -paraquat group than in the paraquat group. Hence, rather than being protective, treatment with dimethylthiourea was associated with increased mortality in paraquat-poisoned rats.

Physiologic correlates of airway collapse in chronic airflow obstruction

Forty percent of 89 patients with chronic airflow obstruction (CAO) demonstrated maximum expiration flow-volume (MEFV) patterns consistent with sudden collapse or marked narrowing of large central airways. In contrast, 43 percent of the CAO patients demonstrated a curvilinear (C) pattern; the remainder (17 percent) were intermediate. Volume displacement plethysmography indicated that the airway collapse (AC) pattern was influenced by, but was not solely, a gas compression artifact. Airway collapse patients had more obstruction and hyperinflation than C patients and also had decreased diffusing capacity, absence of density dependence, reduced lung recoil, and no effort dependence of airflow. Bronchodilator administration in AC patients typically produced large reduction of residual volume and increase of vital capacity, with a smaller increase of airflow. These data suggest that AC patients have significant, partially reversible peripheral airways obstruction plus emphysema. Possible determinants of AC include reduced central airway support, increased peripheral resistance, loss of lung recoil, and increased pleural pressures during forced expiration. The MEFV contour appears to evolve from normal to curvilinear to the AC pattern as the severity of airflow obstruction worsens.

Postprandial exercise-induced anaphylaxis

A variety of systemic reactions associated with exercise are increasingly being recognized. We studied an atopic individual whose job-related activities involved strenuous running that often terminated in an episode of syncope and hypotension preceded by cutaneous pruritus, warmth, urticaria, and angioedema. These attacks occurred only after meals, but no foods appeared to elicit symptoms without subsequent exercise. The subject underwent three exercise challenges in the laboratory under the following conditions: (1) fasting state, with heat-dissipating clothing. (2) fasting, with heat-retention clothes, and (3) after a meal. Blood pressure decreases and minimum skin reactivity were observed for (1) and (2), and reproduction of syncope, hypotension, and further cutaneous manifestation were observed only after (3). Venous and arterial plasma determinations for complement activation (C4, C4d, and CH50) and histamine before, during, and after exercise were not abnormal. Although other vasodepressor mediators may have been liberated, at least part of the mechanism for postprandial exercise-related syncope may be attributed to a shift of blood flow to the splanchnic as well as skeletal muscle vasculature.

Nontuberculous mycobacterial disease. Experience in a southern California hospital

The experience with nontuberculous mycobacterial disease at an "acute-care" hospital in southern California between 1971 and 1981 is reported. Forty-five patients with nontuberculous mycobacterial or Mycobacterium bovis-caused disease were identified by retrospective review. Of these, 31 patients (69%) had pulmonary infection alone, nine (20%) had cervical lymphadenitis, two (4%) had disseminated disease, two (4%) had cutaneous infection, and one had soft tissue infection. Nonmycobacterial pulmonary disease was noted in 15 (33%) of the patients and underlying malignant neoplasms were noted in eight (18%). Symptoms most frequently reported at initial examinations of patients with pulmonary disease were cough, weight loss, sputum production, and fatigue. Response to therapy was more successful in patients with Mycobacterium kansasii-caused disease than in those with Mycobacterium avium-intracellulare-caused pulmonary disease. We conclude that nontuberculous mycobacterial disease is not rare in the general hospital setting in southern California.

A comparison of incremental exercise tests during cycle and treadmill ergometry

We evaluated a short-duration maximum exercise test by comparing a 15-s incremental exercise protocol with a 1-min incremental method. Twenty normal men and women were studied using cycle and/or treadmill ergometry. In subjects tested on both exercise devices, anaerobic threshold and maximal oxygen uptake (VO2max) were higher for both protocols on the treadmill than on the cycle ergometer (P less than 0.001). However, when the 15-s and 1-min tests were compared using the same device (treadmill or cycle), there were no significant differences between protocols in anaerobic threshold or maximum exercise values of minute ventilation, respiratory rate, tidal volume, VO2max, oxygen pulse, and peak expiratory flow rate. Linear regression analyses indicated differences between the 15-s and 1-min protocols when cardiopulmonary measurements were related to power; however, the two protocols were comparable when cardiopulmonary data were related to oxygen uptake. Comparisons between protocols or between exercise devices were not systematically different in large vs small individuals, or in men vs women. Short-duration incremental exercise tests appear to be reliable, practical methods for assessing exercise performance in normal individuals.

Frequency and spectrum of pulmonary diseases in patients with chronic renal failure associated with spinal cord injury

We reviewed autopsy records from 20 patients with long-standing spinal cord injury and chronic renal failure. Only 1 patient had normal pulmonary findings at autopsy. Acute and chronic pulmonary diseases were found in 16/20 and 17/20 patients, respectively. Pneumonia and fluid overload were the most common acute diseases. Interstitial and pleural fibrosis were the most common chronic diseases. However, a variety of illnesses including pulmonary amyloidosis, calcification, and arteriosclerosis were also found. Arterial blood gas studies indicated a high prevalence of hypoxemia. We concluded that significant pulmonary abnormalities are present in almost all spinal cord injury-chronic renal failure patients.

Partial and complete maximum expiratory flow-volume curves in asthmatic patients with spontaneous bronchospasm

Bronchodilatation follows a deep inspiration in normal subjects with pharmacologically induced bronchoconstriction. To determine to what extent this occurs in asthmatic patients with spontaneous bronchospasm, we obtained partial (PEFV) and complete (MEFV) maximum expiratory flow volume curves in 20 adults (helium-oxygen responders and nonresponders) and 13 children with asthma. We measured maximum expiratory flow at 25 percent of forced vital capacity from the partial (Vmax - p) and complete (Vmax - c) flow-volume curves and expressed this relationship as the Vmax - p/Vmax - c ratio. Three of the adult subjects and one of the children had a V max-p/V max-c less than 1.0. Following inhalation of nebulized bronchodilators, none of the children or adults had a Vmax - p/Vmax - c ratio less than 1.0. Reasons for Vmax - p to be higher than Vmax - c include bronchoconstriction, decreased lung elastic recoil following a deep inspiration, and time dependence of maximum expiratory flow due to lung inhomogeneity. We conclude that asthmatic patients with spontaneous bronchospasm are only seldom able to obtain bronchodilation following a deep inspiration.

Lung pathology in chronic hemodialysis patients

To determine the spectrum and the relative frequencies of different pulmonary diseases in chronic renal failure (CFR) patients, we reviewed autopsy records from 46 chronic hemodialysis patients with end-stage renal disease of various etiologies. Pathological abnormalities were observed in the lungs of all but one patient. Acute and chronic lung diseases were found in 95.7% and 80.4% of subjects respectively. The most common acute diseases were pulmonary infections (pneumonia, lung abscess, empyema) and fluid overload. The most common chronic process was interstitial fibrosis. Other relatively common chronic diseases included pleural fibrosis and/or pleuritis as well as pulmonary arteriosclerosis, hemorrhage, thromboembolism and calcification. The incidences of granulomatous lung diseases, pulmonary amyloidosis and metastatic lung tumors were also higher than expected. Relative incidences of the different pulmonary diseases did not appear to be related to the etiology of CFR; rather, lung abnormalities were common in CFR of all etiologies.

Chronic airflow obstruction in a patient with pigeon breeder's lung: prevalence of IgE antibodies to avian antigens

We report a case of pigeon breeder's lung in which chronic airflow obstruction and not restrictive lung disease was predominant. The patient's disease was severe enough to require hospitalizations twice to reverse respiratory failure. Helium-oxygen flow volume curves were consistent with a peripheral site of flow limitation, and immunoserological studies disclosed specific IgE as well as precipitating antibody responses to pigeon antigens. Immunological studies on 18 other patients with pigeon breeder's lung demonstrated a prevalence rate of specific IgE antibodies of 78%, a frequency not previously recognized. Exposures to avian antigens must be considered in patients with obstructive lung disease of unknown etiology.

Ultrastructural evidence of pulmonary capillary endothelial damage from paraquat

Because of lack of agreement concerning the toxicity of paraquat to the pulmonary microvasculature, we have undertaken an electron microscopic study of lungs of paraquat-treated rats. Rats were injected with paraquat or sterile water (controls) intraperitoneally; the animals were then killed at 24-h intervals for 10 days post-injection. In the control animals, lung ultrastructure remained normal throughout the study. In treated animals, the initial evidence of alveolar epithelial injury occurred 24 h post-paraquat. By 48 h, severe fragmentation and desquamation of membranous pneumocytes occurred, and both alveolar and interstitial edema were present. Epithelial damage was maximal 72-96 h post-paraquat. Pulmonary capillary endothelial abnormalities were less extensive than the alveolar epithelial lesions. Endothelial damage was first observed 48 h post-paraquat. In endothelial cells on the septal (thick) side of the capillaries, the number of pinocytotic vesicles was significantly increased (P less than 0.05) from 48 to 96 h post-paraquat. In endothelium adjacent to damaged epithelium, abnormalities included hydration, fragmentation, discontinuity, and widened intercellular junctions; these were maximal 72-96 h post-paraquat. Although other mechanisms are probably important, damaged pulmonary capillary endothelium seems to be a factor favoring paraquat-induced pulmonary edema.

Effects of breathing retraining in patients with chronic obstructive pulmonary disease

Subjects with severe chronic obstructive pulmonary disease (COPD) were studied to evaluate the effects of breathing retraining (BRT) on exercise tolerance. Twenty-two subjects exercised on a treadmill three times weekly for six weeks. Twelve of the subjects (controls) then exercised for three more weeks; the other ten subjects received three more weeks of exercise reconditioning plus BRT. Results of routine pulmonary function and exercise tests were similar in both groups at the beginning of the study and after six weeks of exercise. However, in the last three weeks of the study, increments in exercise performance were significantly greater in the BRT subjects than in controls (P less than .002). Following BRT, respiratory rate during exercise decreased (P less than .005) and tidal volume and PaO2 during exercise increased (P less than .05). Thus, these data suggest that BRT increases exercise performance in subjects with severe COPD.

Relationship between sites of airflow limitation and severity of chronic airflow obstruction

We studied the relationship between sites of airflow limitation and severity of chronic obstructive pulmonary disease. Pre- and postbronchodilator physiologic testing was performed in 30 subjects with chronic airflow obstruction (CAO). Pulmonary function, including the increase in maximal expiratory flow at 50% of vital capacity after helium-oxygen breathing (delta VEmax50), was reduced before and after inhalation of 1.3 mu mg of metaproterenol. Significant correlations were present between values for delta VEmax50 and measurements of expiratory flow (p < 0.001). In subjects with severe CAO (one-second forced expiratory volume less than or equal to 1.2 L; percentage ratio of one-second forced expiratory volume to forced vital capacity < 50%), delta VEmax50 was always abnormally decreased. An inverse relationship was present between initial delta VEmax50 and changes in delta VEmax50 after inhalation of metaproterenol (p < 0.001). These results suggest that the site of airflow limitation becomes progressively more peripheral as CAO worsens, and that severe CAO is usually associated with peripheral sites of airflow limitation.

Site and duration of bronchodilation in asthmatic patients after oral administration of terbutaline

We compared pulmonary function in 15 asthmatic subjects before and after ingestion of 5 mg terbutaline and placebo. Measurements of maximal expiratory flow (VEmax), density-dependence of VEmax (delta VEmax50), volume of isoflow (Viso V), residual volume (RV), and closing capacity (CC) were performed before and 15, 135, 255, and 375 minutes after both treatments. After placebo VEmax improved mildly (P < 0.05) but no significant changes occurred in delta VEmax50, VisoV, RV, or CC. After terbutaline, VEmax increased significantly and VisoV, RV, and CC decreased significantly at all time periods studied. In addition delta VEmax50 increased compared to baseline at 15 and 135 minutes (P < 0.05) and compared to placebo at 135 and 255 minutes (P < 0.05). In our study, orally administered terbutaline apparently caused predominant peripheral airways bronchodilatation in the first few hours after ingestion. Afterwards, the predominant small airways effect appeared to wane, and large and small airways were dilated proportionately equally 375 minutes after oral administration of terbutaline.

Inhaled atropine sulfate in acute asthma

We administered inhaled atropine sulfate to acute asthmatics already receiving therapeutic doses of adrenergic agonists, theophylline, and corticosteroids. Following atropine, hyperinflation diminished whereas vital capacity and expiratory flow rates breathing air and helium-oxygen increased (p less than 0.025 - p less than 0.005). Initial density dependence correlated inversely with changes in density dependence after atropine (r = -0.69, p less than 0.001). We conclude that: (1) inhaled atropine sulfate was effective therapy for acutely ill asthmatics already being treated with multiple antiasthmatic agents; (2) atropine caused large and peripheral airways bronchodilatation, and (3) the predominant site of bronchodilatation after atropine was related to the site of flow limitation before atropine.

In vivo and in vitro cell-mediated immunity to tetanus toxoid in adults

The purpose of this study was to evaluate tetanus toxoid (TT) as an indicator of cutaneous delayed hypersensitivity (CDH) in adults. Fifty-two normal subjects, aged 25 to 64 yr, were skin tested with TT and streptokinase-streptodornase (SK/SD). Lymphocyte transformation was studied in seven normal TT reactors, four normal TT nonreactors, and seven hospitalized anergic patients. CDH was common with both TT and SK/SD; 90% of the adults, aged 25 to 39 yr, had CDH reactions to TT and 79% had CDH reactions to SK/SD. In adults aged 40 to 64 yr, 75% had DCH reactions to TT and 59% had CDH reactions to SK/SD. Lymphocyte transformation to TT correlated well with TT skin-test results. Punch biopsy specimens of TT reactions 48 hr after skin testing demonstrated DCH. We conclude that TT is an excellent antigen for assessing the presence or absence of CDH in adults aged 25 to 64 yr.

Pulmonary disease in workers exposed to papain: clinico-physiological and immunological studies

Of the twenty-three employees at a pharmaceutical plant manufacturing a new product containing papain, twelve had respiratory symptoms of cough, wheezing, dyspnoea, or chest paint. Most were studied with in-depth interviews by a doctor, extensive pulmonary function tests, and immunoserological tests for IgE and precipitating antibodies specific for papain, as well as total IgE antibodies to common natural allergens. There were significant correlates (all P values < 0.05) between the presence of specific IgE antibodies to papain and decreases of FEV1, FEF75--85, TLC, RV, and response to bronchodilators as percentage change from baseline for all spirographic flow rates. Atopic workers developed pulmonary symptoms and antipapain antibodies significantly sooner after papain exposure than did the others. Duration of exposure had no effect on symptomatology, pulmonary function, or immunological response. However, those judged to have the greatest amount of dust exposure per work-day had significantly more pulmonary symptoms (P < 0.005). Papain produced lung diseases by acting as an inhalant allergen rather than a proteolytic enzyme. Papain is a potent sensitizer in humans for the production of respiratory disease. The pulmonary reactions, based on physiological data, seem to involve small airways, alveolar, and interstitial lung tissue in an inflammatory rather than destructive manner, and thus resemble bronchitis and interstitial lung disease rather than pulmonary emphysema or typical bronchial asthma.

Relationship between the site of airflow limitation and localization of the bronchodilator response in asthma

In an effort to determine the relationship between the major sites of airflow limitation and bronchodilator action, physiologic studies were performed in 65 asthmatics before and after the administration of isoproterenol, metaproterenol, or terbutaline. Before the administration of a bronchodilator, the results of routine pulmonary function tests were abnormal; the mean increment in maximal expiratory flow at 50% of forced vital capacity (delta VEmax50) after breathing 80% helium-20% oxygen (He-O2) was reduced (p < 0.001). Prebronchodilator values of delta VEmax50 correlated linearly with VEmax50 breathing air (r = + 0.68, p < 0.001). These data suggested that airflow limitation becomes more peripheral as asthma becomes more severe. After the bronchodilator administration, the results of routine pulmonary function studies improved; delta VEmax50 either increased or decreased, depending upon the prebronchodilator values. Density-dependence tended to (1) increase in subjects with low prebronchodilator values of delta VEmax50, and (2) decrease in subjects with high prebronchodilator values of delta VEmax50. Hence, these results suggested that predominant sites of bronchodilatation in asthmatics are related to the prebronchodilator sites of airflow limitation.

Response to inhaled metaproterenol and isoproterenol in asthmatic and normal subjects

Pulmonary function tests were performed before and after inhalation of 1.3 mg of metaproterenol sulfate or 150 microgram of isoproterenol hydrochloride by 40 asthmatic and 40 normal subjects. PHysiologic measurements included spirometric testing, plethysmographic studies, and maximal expiratory flow-volume curves obtained after inhalation of air and a mixture of 80 percent helium and 20 percent oxygen. In the normal subjects, pulmonary function improved significantly after inhalation of both metaproterenol and isoproterenol. There was no significant difference in responsiveness to either bronchodilator drug. In the asthmatic subjects, pulmonary function also improved significantly after both bronchodilator agents. The sites of predominant bronchodilatation were similar in the asthmatic subjects after both metaproterenol and isoproterenol; however, bronchodilatation was better overall (P less than 0.005) and for most individual tests with metaproterenol. The greater efficacy of metaproterenol in asthmatic subjects but not in normal subjects can be explained by (1) different doses of the bronchodilator drug and (2) differing bronchodilator dose-response relationships in asthmatic and normal subjects.

P pulmonale in status asthmaticus

We studied 129 patients during acute, severe asthmatic attacks. Electrocardiograms showed P pulmonale in 49% of patients who had an arterial carbon dioxide tension (PaCo2) greater than or equal to 45 mm Hg and an arterial pH less than or equal to 7.37, whereas P pulmonale was present in only 2.5% of asthmatics who had a PaCO2 less than or equal to 44 mm Hg and a pH greater than or equal to 7.38 (p less than 0.001). P wave and QRS axes were 79 +/- 8 degrees and 80 +/- 20 degrees, respectively, in the presence of P pulmonale. When P pulmonale disappeared, the P wave and QRS axes shifted significantly to the left (p less than 0.001). Electrocardiographic P pulmonale persisted 12 to 60 hr after correction of hypoxemia, hypercapnia, and acidosis. In 7 patients with P pulmonale and respiratory acidosis, cardiac catheterization demonstrated normal artery pressures (PAPs) measured relative to atmospheric pressure. In 12 of these peak inspiratory pulmonary artery transmural pressures (PATPs) were increased. Since increased right heart transumural pressures could result in chamber distention, these data are consistent with the hypothesis that reversible P pulmonale in status asthmaticus is explainable on the basis of markedly negative tidal pleural pressures and increased right heart transmural pressures.

Large bronchial casts

Unusually large bronchial casts developed in four patients. In two, the casts were associated with pneumonia. In one, a large RBC cast resulted from a complication of fiberoptic bronchoscopy. Bronchial casts developed in an additional patient as a manifestation of plastic bronchitis. Although unusual, bronchial cast formation may complicate a number of hypersecretory pulmonary diseases. Therapy ordinarily includes specific measures to treat the underlying disease state and maneuvers designed to remove or facilitate the expectoration of bronchial casts.