Acute and subacute bronchial effects of oral cannabinoids

The bronchodilating activity of oral cannabinoids was evaluated in three double-blind experiments that involved the study of dose-response and interactive relationships and the potential development of tolerance. Data indicated that delta 8-tetrahydrocannabinol (delta 8-THC), cannabinol (CBN), and cannabidiol (CBD) in maximal doses of 75 mg, 1200 mg, and 1200 mg, respectively, did not induce significant dose-related physiologic effects in experienced marijuana smokers. delta 8-THC (75 mg) was, however, associated with bronchodilation, tachycardia, and peak highs less than that after delta 9-tetrahydrocannabinol (delta 9-THC). The combinations of CBN and CBD with low-dose delta 9-THC (5 mg) did not induce significant bronchodilation but did exert interactive effects on heart rate and "high." A 20-day study of daily delta 9-THC (20 mg), CBN (600 mg), and CBD (1200 mg) did not indicate tolerance or reverse tolerance to any drug. We conclude that delta 9-THC and, to a lesser extent, delta 8-THC, have acute bronchodilator activity but that CBN, CBD, and their combinations do not provide effective bronchodilation. The daily use of delta 9-THC was not associated with clinical tolerance.

Prevalence and clinical correlates of pulmonary arterial hypertension in progressive systemic sclerosis

Forty-nine patients with progressive systemic sclerosis who had undergone extensive studies including pulmonary artery catheterization as part of an ongoing prospective study of the natural course of progressive systemic sclerosis were evaluated. The overall prevalence of pulmonary arterial hypertension in this population of patients with progressive systemic sclerosis was 33 percent, and among 10 subjects with the CREST syndrome the prevalence of pulmonary hypertension was 50 percent. The relation between pulmonary arterial hypertension documented at catheterization and abnormal results of noninvasive studies suggesting pulmonary hypertension, including physical examination, chest x-ray, electrocardiography, echocardiography, single-breath diffusing capacity, and vital capacity, was studied. Diffusing capacity was significantly lower in those patients with definite pulmonary hypertension (mean pulmonary artery pressure of 22 mg Hg or more) compared with those with a normal mean pulmonary artery pressure, and a diffusing capacity below 43 percent of predicted showed the greatest sensitivity (67 percent) of any single diagnostic test in detecting definite pulmonary hypertension. Chest x-ray suggesting pulmonary hypertension was the least sensitive of the tests evaluated, but showed the greatest specificity (100 percent) in identifying patients with pulmonary hypertension. A classification matrix based on discriminant function analysis utilizing the combination of diffusing capacity below 43 percent of predicted and chest x-ray and electrocardiographic findings correctly identified 75 percent of patients with definite pulmonary hypertension and 97 percent of patients with a normal pulmonary artery pressure, but failed to identify correctly patients with mild pulmonary hypertension (mean pulmonary artery pressure of 20 mm Hg). These findings indicate that specific noninvasive studies are helpful in assessing the likelihood of normal or definitely elevated pulmonary artery pressures in patients with progressive systemic sclerosis, but patients with mild pulmonary hypertension are not likely to be identified by these noninvasive studies.

Repeat fiberoptic bronchoscopy in patients with recurrent, unexplained hemoptysis

Repeat fiberoptic bronchoscopy (FB) is indicated in patients with recurrent, unexplained hemoptysis to localize and/or diagnose the source of bleeding. The results of 34 bronchoscopies in 14 patients over a 6-year period were examined. 10 patients had 2 FBs each and 1 patient had 5 procedures at varying intervals. Only early FB detected active bleeding (12/25) early FBs) and localized a bleeding site (10/25). Definitive diagnoses (6/34 FBs) occurred only in patients with lung malignancy and were not necessarily influenced by the timing or frequency of FB. Clinical diagnoses and management were infrequently altered by each FB, except for management of malignancy. Thus, early, repeat FB in this diagnostically difficult group of patients contributes limited immediate information and minimally changes therapy in patients with nonneoplastic conditions. Despite these limitations, direct bronchial visualization by FB remains the most reliable standard available for localizing and, to a lesser extent, diagnosing the etiology of recurrent hemoptysis.

Comparison of bronchial effects of nabilone and terbutaline in healthy and asthmatic subjects

The acute bronchomotor effect of nabilone, a synthetic cannabinoid compound, was compared to that of terbutaline sulfate and placebo in six healthy and six asthmatic subjects. Bronchodilation following nabilone was intermediate between that of terbutaline and placebo in the healthy subjects but was equivalent to placebo in the asthmatics. We conclude that oral nabilone (2 mg) does not result in significant acute bronchodilation in patients with asthma.

Effect of pneumatic trousers on pulmonary function

Little information is available concerning the effect of pneumatic antishock trousers (PT) on pulmonary function. To examine this issue, we measured the effects of PT inflation on forced expired volumes, subdivisions of lung volumes, quasistatic lung compliance, single-breath diffusing capacity for carbon monoxide, and transdiaphragmatic pressure at resting lung volume in 10 healthy nonsmoking adults. All subjects were studied seated without PT, supine with PT uninflated, and supine with PT inflated to 100 mm Hg. When seated subjects assumed the supine position without PT inflation, significant reductions were found in the forced expired volume in 1 sec, in subdivisions of lung volume, total lung capacity (TLC), functional residual capacity (FRC), expiratory reserve volume (ERV) and in transdiaphragmatic pressure. However, PT inflation itself did not produce significant changes in any of the measured pulmonary indices except transdiaphragmatic pressure. We conclude that PT inflation in supine normovolemic individuals does not produce acutely significant alterations in lung function.

Residents' training goals in respiratory knowledge and skills: perspective of three parties

Medical residents, full-time respiratory teaching staff, and community-based doctors rated the importance of fifty-five respiratory training goals involving knowledge and skills necessary for the future practices of all medical residents. Residents also rated their perceived preparedness in these training areas. Intra- and inter-group analyses indicated that residents agreed more often, and consistently assigned more importance (94% of goals) to the training goals, than did the teachers and doctors. Although the residents considered themselves prepared for 69% of the training goals, they also had moderate intra-group disagreement. These results may reflect variable training experiences and/or institutional practices, but areas of less than adequate preparation were identified and can be corrected. The other two groups were in general agreement except regarding some clinical skills. This study offers possible explanations for the group responses and indicates the potential benefit for groups to discuss, identify, and survey training goals.

The value of open lung biopsy in the immunosuppressed patient

To evaluate the impact of the open lung biopsy on diagnosis and therapy in the immunosuppressed patient, 68 such patients managed at UCLA from 1975 to 1980 were reviewed. Most had hematologic malignancies, and all were severely immunosuppressed. The rates of surgical mortality (1 operative death) and morbidity were minimal. There were 10 diagnostic differences apparent when biopsy results were compared with autopsy findings in 28 autopsied patients. Therapy was initiated or modified in 19 patients on the basis of open lung biopsy. Forty-four patients lived 1 year or less, 14 for more than 1 year, and 10 were lost to follow-up. Of 42 patients with an untreatable disease on the basis of lung biopsy, 67% died and 33% lived to leave the hospital. Of 25 patients with a treatable disease, 56% died and 44% left the hospital. Of 28 autopsied patients, only 12 were receiving appropriate medication at time of death despite biopsy. The patient whose disease is generally characterized by brief survival like acute leukemia, and whose situation is most desperate, unfortunately benefits least from open lung biopsy. We conclude that this procedure has only a modest impact in the management of these critically ill patients and should be used conservatively.

Clinical efficacy of early and delayed fiberoptic bronchoscopy in patients with hemoptysis

We analyzed the records of 129 consecutive patients with hemoptysis to evaluate whether or not early (during hemoptysis or during the 48 h after hemoptysis stopped) fiberoptic bronchoscopy (FB) more frequently localized and/or diagnosed the source of bleeding and influenced clinical outcome than delayed FB (48 h or more after hemoptysis stopped). Patients were divided into 3 groups on the basis of their final diagnoses: neoplasm (31 patients), bronchitis/bronchiectasis (52 patients), and miscellaneous (46 patients). Although the likelihood of visualizing active bleeding (41 versus 8%) or its site (34 versus 11%) was significantly higher with early versus delayed FB, respectively, neither active bleeding nor a bleeding site were visualized in at least 60% of the 92 patients who underwent early FB. Definitive (endoscopic) diagnoses by early or delayed FB occurred primarily in patients with neoplasm. Clinical outcome based on the results of FB was not significantly different between the early and delayed groups. Thus, early, single FB was generally neither diagnostic nor therapeutically decisive in these patients with hemoptysis.

Alcohol-induced bronchospasm in an asthmatic patient: pharmacologic evaluation of the mechanism

A 23-year-old Asian with histamine-reactive asthma complained of recurrent chest tightness, nasal congestion and flushing immediately after drinking minimal amounts of alcoholic beverages. He was extensively studied to determine the possible mechanism of his alcohol-induced respiratory symptoms. Drinking of either beer or 95 percent ethanol in apple juice immediately provoked vasomotor signs and moderately severe bronchospasm (54 percent and 73 percent decreases in specific airway conductance, respectively), which spontaneously improved over 30 minutes and two hours, respectively. Intravenous and inhaled ethanol caused less bronchospasm than observed with oral ethanol, and recovery was rapid. Pretreatment with cromolyn sodium (inhaled or oral) and isoproterenol had no inhibitory effect on the alcohol-induced bronchoconstriction, whereas atropine, acetylsalicylic acid, cyproheptadine, and chlorpheniramine appeared to have a partial inhibitory effect. Approximately 70 percent inhibition was observed after chlorpheniramine. Observations in this patient suggest that the bronchoconstriction induced by alcoholic beverages is related to their ethanol content and may be related to formation or release of one or more bronchoconstrictor and vasoactive compounds, including a stimulant of histamine1-receptors. The route of ethanol administration may also influence the bronchospastic response.

Survey of hospital doctors' training goals in diagnosis and management of pulmonary diseases

Although subspecialty training goals for junior hospital doctors have not been evaluated, they are potentially useful for assessing clinical competence. A questionnaire was sent to medical residents, full-time pulmonary teaching staff, and community-based physicians who were asked to rate the importance of diagnosing and managing selected pulmonary diseases for the future practices of young hospital doctors. The latter also rated their perceived preparedness for the same training goals. Generally good intra- and intergroup agreement about the relevance of most of the training goals was observed, although the hospital doctors rated a greater number of items to be more important than did the two other groups. This finding may be attributed to institutional influences and to many clinical abilities expected of all physicians. Immunological or fibrotic and paediatric respiratory disorders were rated least important by most respondents. The hospital doctors disagreed on the basis of the distribution of their ratings about their preparedness for the same goals, which probably reflects varying training experiences and background. The process of developing general professional training goals in a subspecialty requires discussion, identification, and consensus to identify and potentially correct areas of weakness, with allowance for institutional training patterns. A survey such as described in this study can provide data that can help measure clinical competence and support or define curricular changes.

Silicosis due to intentional inhalation of abrasive scouring powder. Case report with long-term survival and vasculitic sequelae

Silicosis due to inhalation of abrasive scouring powder is now an unusual event. We report a nonindustrial case of acute silicosis due to intentional inhalation of commercial, silica-containing scouring powder. This case is unique in that the patient had a 20 year survival (after onset of symptoms) with typical roentgenographic and histopathologic changes of silicosis, and evidence of immune complex disease in extrapulmonary tissues.

Adult respiratory distress syndrome after venous air embolism

Venous air embolism is not commonly believed to produce the adult respiratory distress syndrome. We present a nonsurgical case of venous air embolism followed by the development of this syndrome. Other causes of adult respiratory distress syndrome were excluded. Physicians should be alerted to its possible occurrence and the need for appropriate therapy.

Small airways in progressive systemic sclerosis (PSS)

Obstructive disease involving peripheral airways has been noted in diffuse interstitial pulmonary disease, including sarcoidosis and cryptogenic fibrosing alveolitis. The possibility of obstruction of small airways in progressive systemic sclerosis (PSS) has been suggested by widespread bronchiolectasis and peribronchial fibrosis noted at necropsy. We performed pulmonary function studies in 39 subjects (22 nonsmokers and 17 smokers) with PSS, most of whom had functional evidence of interstitial pulmonary involvement (increased static recoil pressure and reduced diffusing capacity). The 1 second forced expiratory volume to forced vital capacity ratio (FEV1:FVC) was normal in all subjects. Although the severity of the restrictive process was greater in nonsmokers compared with that in smokers, the maximal mid-expiratory flow rate, closing volume, closing capacity, volume of isoflow, change in maximal expiratory flow at 50 per cent of vital capacity during 80 per cent helium--20 per cent oxygen breathing compared with air breathing (delta Vmax50), ratio of dynamic to static lung compliance at different breathing frequencies and upstream airway conductance at static recoil pressures of 5 and 10 cm H2O were nearly always normal in the nonsmokers but were frequently abnormal in the smokers with PSS. These findings suggest that diffuse interstitial pulmonary disease due to PSS generally does not lead to functional evidence of obstruction in peripheral airways and that when the latter is found it can likely be attributed to the effects of concomitant cigarette smoking.

Fat embolism syndrome: a puzzling phenomenon

Fat emboli are a life-threatening source of respiratory insufficiency. Whether they are of mechanical or chemical origin remains a subject of controversy. Fat embolism syndrome is most often seen after fracture of long bones, and immobilization of the fracture site may decrease risk of its development. Adequate oxygenation is the most important aspect of therapy; most patients given vigorous supportive treatment recover with no residual lung injury.

Alterations in distribution of blood flow to the lung's diffusion surfaces during exercise

We measured simultaneously, by single breath methods, pulmonary capillary blood flow (Q(c)), carbon monoxide diffusing capacity (DL(CO)), and isotopic oxygen ((18)O(18)O) diffusing capacity (DL(18) (O2)) in five normal males during conditions of rest and moderate exercise at mixed venous O(2) tensions (PO(2) 33-44 mm Hg). During moderate exercise at a work load of 100 W. pulmonary capillary blood flow increased from 6.9+/-1.5 to 12.9+/-3.4 min(-1) and DL(18) (O2) increased from 25+/-4 to 43+/-3 ml.min(-1).mm Hg(-1), whereas DL(CO) showed no significant change (45+/-5 to 49+/-10 ml.min(-1).mm Hg(-1)). DL(18) (O2) increased proportionally to Q(c) (r = 0.74), where DL(CO) did not (r = 0.08). The greater increase in DL(18) (O2) during exercise can be explained by a more homogeneous diffusion/perfusion (DL(O2)/Q(c)) distribution in the individual respiratory exchange units during exercise. This improved distribution of DL(O2)/Q(c) acts to help prevent an increase in alveolar-arterial O(2) tension difference from developing despite the decrease in pulmonary erythrocyte transit times that occur during exercise. The insignificant rise in DL(CO) with exercise under these hypoxic breathholding conditions may result from pulmonary vasomotor responses to short-term hypoxia or from relative insensitivity of DL(CO) to moderate levels of exercise.