Evidence of chronic damage to the pulmonary microcirculation in habitual users of alkaloidal ("crack") cocaine

Salivary protein candidates for biomarkers of oral disorders in people with a crack cocaine use disorder

The use of cocaine and its main derivative, crack, can cause some systemic effects that may lead to the development of some oral disorders. To assess the oral health of people with a crack cocaine use disorder and identify salivary protein candidates for biomarkers of oral disorders. A total of 40 volunteers hospitalized for rehabilitation for crack cocaine addiction were enrolled; nine were randomly selected for proteomic analysis. Intraoral examination, report of DMFT, gingival and plaque index, xerostomia, and non-stimulated saliva collection were performed. A list of proteins identified was generated from the UniProt database and manually revised. The mean age (n=40) was 32 (±8.88; 18-51) years; the mean DMFT index was 16±7.70; the mean plaque and gingival index were 2.07±0.65 and 2.12±0.64, respectively; and 20 (50%) volunteers reported xerostomia. We identified 305 salivary proteins (n=9), of which 23 were classified as candidate for biomarkers associated with 14 oral disorders. The highest number of candidates for biomarkers was associated with carcinoma of head and neck (n=7) and nasopharyngeal carcinoma (n=7), followed by periodontitis (n=6). People with a crack cocaine use disorder had an increased risk of dental caries and gingival inflammation; less than half had oral mucosal alterations, and half experienced xerostomia. As possible biomarkers for 14 oral disorders, 23 salivary proteins were identified. Oral cancer and periodontal disease were the most often associated disorders with biomarkers.

Cocaine Use and Pulmonary Hypertension

Evidence linking cocaine to the risk of pulmonary hypertension (PH) is limited and inconsistent. We examined whether cocaine use, in the absence of other known causes of PH, was associated with elevated systolic pulmonary artery pressure (sPAP) and increased probability of PH. We compared patients with documented cocaine use to a randomly selected age, sex, and race-matched control group without history of cocaine use. All participants had no known causes of PH and underwent echocardiography for noninvasive estimation of sPAP. We used routinely reported echocardiographic parameters and contemporary guidelines to grade the probability of PH. In 88 patients with documented cocaine use (mean age ± standard deviation 51.7 ± 9.5 years), 33% were women and 89% were of Black race. The commonest route of cocaine use was smoking (74%). Cocaine users compared with the control group had significantly higher sPAP (mean ± standard deviation, 30.1 ± 13.1 vs 22.0 ± 9.8 mm Hg, p <0.001) and greater likelihood of PH (25% vs 10%, p = 0.012). In multivariable analyses adjusted for potential confounders including left ventricular diastolic dysfunction, cocaine use conferred a fivefold greater odds of echocardiographic PH (p = 0.006). Additionally, a stepwise increase in the likelihood of PH was noted across cocaine users with negative or no drug screen on the day of echocardiography to cocaine users with a positive drug screen (multivariable p for trend = 0.008). In conclusion, cocaine use was associated with a higher sPAP and an increased likelihood of echocardiographic PH with a probable acute-on-chronic effect.

[Pulmonary complications in cocaine users]

Cocaine can be responsible for many psychiatric and/or somatic disorders. The aim of this systematic literature review of data was to expose relations between cocaine use and pulmonary complications. Cocaine can be responsible for acute respiratory symptoms (cough, black sputum, hemoptysis, dyspnea, wheezing, chest pain) and for various pulmonary disorders including barotrauma (pneumothorax, pneumomediastinum, subcutaneous emphysema, pneumopericardium), airway damage, asthma, bronchiolitis obliterans with organizing pneumonia, acute pulmonary edema, alveolar hemorrhage, alveolar pneumonia with carbonaceous material, bullous emphysema, acute eosinophilic pneumonia, pulmonary granulomatosis caused by talc or cellulose, interstitial pneumonitis and pulmonary fibrosis, vasculitis, pulmonary hypertension, pulmonary embolism and pulmonary infarction, mycotic pulmonary arterial aneurysms, septic emboli, aspiration pneumonia, community-acquired pneumonia, HIV-related opportunistic infections, latent tuberculosis infection, pulmonary tuberculosis, lung cancer and crack lung. Some of these complications are serious and may have a fatal outcome. Pulmonary function tests, thoracic tomodensitometry, bronchial fibroscopy with bronchoalveolar lavage and lung scintigraphy may be an aid to the diagnosis of these pulmonary compications. Cocaine use must be sought in case of respiratory symptoms in young persons.

Cocaine-induced pulmonary changes: HRCT findings

Objective:

To evaluate HRCT scans of the chest in 22 patients with cocaine-induced pulmonary disease.

Methods:

We included patients between 19 and 52 years of age. The HRCT scans were evaluated by two radiologists independently, discordant results being resolved by consensus. The inclusion criterion was an HRCT scan showing abnormalities that were temporally related to cocaine use, with no other apparent causal factors.

Results:

In 8 patients (36.4%), the clinical and tomographic findings were consistent with "crack lung", those cases being studied separately. The major HRCT findings in that subgroup of patients included ground-glass opacities, in 100% of the cases; consolidations, in 50%; and the halo sign, in 25%. In 12.5% of the cases, smooth septal thickening, paraseptal emphysema, centrilobular nodules, and the tree-in-bud pattern were identified. Among the remaining 14 patients (63.6%), barotrauma was identified in 3 cases, presenting as pneumomediastinum, pneumothorax, and hemopneumothorax, respectively. Talcosis, characterized as perihilar conglomerate masses, architectural distortion, and emphysema, was diagnosed in 3 patients. Other patterns were found less frequently: organizing pneumonia and bullous emphysema, in 2 patients each; and pulmonary infarction, septic embolism, eosinophilic pneumonia, and cardiogenic pulmonary edema, in 1 patient each.

Conclusions:

Pulmonary changes induced by cocaine use are varied and nonspecific. The diagnostic suspicion of cocaine-induced pulmonary disease depends, in most of the cases, on a careful drawing of correlations between clinical and radiological findings.

Stimulants and the lung : review of literature

Illicit stimulants, such as cocaine, amphetamine, and their derivatives (e.g., "ecstasy"), continue to exact heavy toll on health care in both developed and developing countries. The US Department of Health and Human Service reported over one million illicit drug-related emergency department visits in 2010, which was higher than any of the six previous years. Both inhaled and intravenous forms of these substances of abuse can result in a variety of acute and chronic injuries to practically every part of the respiratory tract, leading potentially to permanent morbidities as well as fatal consequences--including but not limited to nasal septum perforation, pulmonary hypertension, pneumothorax, pneumomediastinum, interstitial lung disease, alveolar hemorrhage, reactive airway disease, pulmonary edema, pulmonary granulomatosis, infections, foreign body aspiration, infections, bronchoconstriction, and thermal injuries. Stimulants are all rapidly absorbed substances that can also significantly alter the patient's systemic acid-base balance and central nervous system, thereby leading to further respiratory compromise. Mounting evidence in the past decade has demonstrated that adulterants coinhaled with these substances (e.g., levamisole) and the metabolites of these substances (e.g., cocaethylene) are associated with specific forms of systemic and respiratory complications as well. Recent studies have also demonstrated the effects of stimulants on autoimmune-mediated injuries of the respiratory tract, such as cocaine-induced midline destructive lesions. A persistent challenge to studies involving stimulant-associated respiratory toxidromes is the high prevalence of concomitant usage of various substances by drug abusers, including tobacco smoking. Now more than ever, health care providers must be familiar with the multitude of respiratory toxidromes as well as the diverse pathophysiology related to commonly abused stimulants to provide timely diagnosis and effective treatment.

Does cannabis smoking predispose to lung bulla formation?

OBJECTIVE

The data of a consecutive series of habitual marijuana smokers were retrospectively evaluated and compared with that of non-marijuana smokers to assess differences between the 2 groups.

METHODS

13 consecutive habitual marijuana smokers were referred for treatment of spontaneous pneumothorax. The demographic, clinical, radiological, and pathological findings of these patients were reviewed and compared with 140 non-marijuana smokers treated for the same pathology at the same time.

RESULTS

Bullae were seen in 8/13 (62%) and 110/140 (78%) of marijuana smokers and non-marijuana smokers, respectively. However, when patients less than 35-years old were considered, the incidence of bulla was higher in marijuana smokers than non-marijuana smokers (7/10 vs. 3/10, p < 0.05). The pathological findings showed a greater presence of inflammatory cells in specimens from marijuana smokers than those of non-marijuana smokers (8/11 vs. 2/42, respectively, p < 0.05). No significant differences in hospital stay and clinical outcome were registered between the 2 groups.

CONCLUSIONS

Despite the fact that we were unable to demonstrate that marijuana had a causal role in the development of emphysema, our study showed that marijuana smokers had a higher incidence of inflammatory cells in pathological specimens, which may favor lung injury, thus predisposing to bulla formation.

Preoperative screening and case cancellation in cocaine-abusing veterans scheduled for elective surgery

Background. Perioperative management of cocaine-abusing patients scheduled for elective surgery varies widely based on individual anecdotes and personal experience. Methods. Chiefs of the anesthesia departments in the Veterans Affairs (VA) health system were surveyed to estimate how often they encounter surgical patients with cocaine use. Respondents were asked about their screening criteria, timing of screening, action resulting from positive screening, and if they have a formal policy for management of these patients. Interest in the development of VA guidelines for the perioperative management of patients with a history of cocaine use was also queried. Results. 172 VA anesthesia departments' chiefs were surveyed. Response rate was 62%. Over half of the facilities see cocaine-abusing patients at least once a week (52%). Two thirds of respondents canceled or delayed patients with a positive screen regardless of clinical symptoms. Only eleven facilities (10.6%) have a formal policy. The majority of facilities (80%) thought that having formal guidelines for perioperative management of cocaine-abusing patients would be helpful to some extent. Results. 172 VA anesthesia departments' chiefs were surveyed. Response rate was 62%. Over half of the facilities see cocaine-abusing patients at least once a week (52%). Two thirds of respondents canceled or delayed patients with a positive screen regardless of clinical symptoms. Only eleven facilities (10.6%) have a formal policy. The majority of facilities (80%) thought that having formal guidelines for perioperative management of cocaine-abusing patients would be helpful to some extent. Conclusions. There is a general consensus that formal guidelines would be helpful. Further studies are needed to help formulate evidence-based guidelines for managing patients screening positive for cocaine prior to elective surgery.

[Perforated peptic ulcer: is the form of methamphetamine known as "crystal meth" a new risk factor?]

BACKGROUND

The emergence of new synthetic drugs related to peptic ulcer perforation has been reported. Recently an increase in the use of inhaled methamphetamine has been observed and we have described an association of frequent use with peptic disease symptomatology and perforation.

AIMS

To determine whether methamphetamine use is a factor related to peptic acid disease and perforation and to establish its demographic variables.

MATERIAL AND METHODS

A retrospective, comparative, descriptive, and observational study was carried out through the evaluation of medical records of patients admitted to the Surgery Service with perforated ulcer, within the time frame of January 2002 to March 2005. A descriptive analysis was carried out, along with the Z test, odds ratio, confidence interval, p value and the Student's t test.

RESULTS

Forty-two patients were divided into 2 groups: methamphetamine users (n=25) and nonusers (n=17). There was a statistically significant difference in relation to age, which was lower in the methamphetamine user group (38,7 years vs 58,88 years, p=0.0001). In addition, there was a trend in the user group to develop peptic ulcer perforation at earlier ages compared with the nonuser group (p=0.0001). There were no statistically significant differences between the two groups in regard to clinical presentation.

CONCLUSIONS

Methamphetamine use is related to ulcer perforation in age groups of younger patients when compared with nonuser patients.

Reduced lung function and bullae resulting from illicit drug use

Emphysema is a progressive, disabling disease. Emphysematous bullae form as a result of local areas of alveolar weakness and parenchymal remodeling. They grow as a result of preferential inflation during inspiration and elastic recoil of the surrounding lung tissue. Isolated apical bullae can be a consequence of illicit drug use, as was suspected in this patient. In the case of cocaine and marijuana smoking, direct drug toxicity or drug-induced vasoconstriction presumably contributes to bullae development. LVRS is often used to treat patients with bullae and severe underlying emphysema, although these patients are difficult to assess and their disease course is hard to predict. LVRS is associated with a higher morbidity and mortality. The best candidates for surgery have enlarged, well-localized bullae and minimal underlying lung disease. Early postoperative results include relief of shortness of breath, improved lung function, increased energy level and physical mobility, and improved ability to function during daily activities. LVRS may decrease the need for supplemental oxygen as soon as a few weeks after surgery, and benefits may be sustained for years. The best results are seen in patients with large bullae that cause the greatest compression of almost normal underlying lung. However, clinical and symptomatic improvement may be greater than actual spirometric measurements.

Diffuse alveolar hemorrhage

Diffuse alveolar hemorrhage (DAH) is a life-threatening disorder characterized clinically by the presence of hemoptysis, falling hematocrit, diffuse pulmonary infiltrates and hypoxemic respiratory failure. It refers to bleeding that originates in the pulmonary microvasculature instead of the parenchyma or bronchial circulation. DAH should be considered a medical emergency due to the morbidity and mortality associated with failure to treat the disorder promptly. Pulmonary renal syndromes, connective tissue disorders and drugs make up the majority of the cases of DAH. The treatment of DAH ranges from supportive care and withdrawal of offending drugs to high-dose steroids, immunosuppresents and plasmapharesis. The following review will discuss the clinical, radiographic and pathologic findings in a variety of disorders that cause DAH. Standard treatment options, as well as new treatment options will also be discussed.

A case of large pericardial and pleural effusions associated with pulmonary emboli in a user of crack cocaine

We submit here an unusual case in which a user of crack cocaine presented with progressive dyspnea of subacute duration and was subsequently found to have concurrent pericardial and pleural effusions and pulmonary emboli. To our knowledge, there is only one prior case report that describes a potential causal relationship between crack cocaine and the development of a pleural effusion, via an eosinophilic process. In contrast in our patient, the most probable mechanism is that crack cocaine induced a prothrombotic state that promoted formation of pulmonary emboli, which are known to be directly associated with exudative pleural or pericardial effusions. An alternative hypothesis is that sympathetic activation or neurostimulation, which is mediated through release of adrenergic neurotransmitters by cocaine, may cause inflammatory changes in the pleura or pericardium. Finally, the pericardial effusion, pleural effusion, and pulmonary emboli could be concurrent but independent processes.

"Crack lung and heart" presenting after chemotherapy in a 65-year-old man with non-Hodgkin lymphoma

Crack cocaine can cause a variety of pulmonary and cardiac complications. Pulmonary findings in a 65- year-old man with non-Hodgkin lymphoma who presented with shortness of breath not resolving with antibiotics are presented here. The usual manifestation of “crack lung” in an unusual clinical circumstance underlines the importance of a clinical history in such cases. The finding of “crack lung” preceded the diagnosis of probable “crack heart.” No other similar published case reports could be identified in the literature.

Crack cocaine use increases the incidence of AIDS-defining events in French Guiana

We conducted a retrospective cohort study to determine the influence of crack cocaine use on the outcomes of HIV infection. The use of crack cocaine was associated with an increased incidence of AIDS: 27.8 per 100 person-years versus 6.6 per 100 person-years for nonusers, adjusted hazard ratio = 3.8 (1.9-7.5), P < 0.001. More specifically, crack users had a greater incidence of disseminated histoplasmosis, pneumocystosis, pulmonary tuberculosis, bacterial pneumonia, oesophageal candidiasis, cerebral toxoplasmosis, salmonellosis, and genital herpes. The care of HIV-infected crack users is particularly challenging and requires additional efforts to reduce the high morbidity of these patients.

Effects of chronic exposure to crack cocaine on the respiratory tract of mice

Smoked cocaine (crack cocaine) causes several forms of injury to the respiratory tract, including asthma exacerbations, lung edema and hemorrhage, and nasal mucosal alterations. Few studies, however, have assessed respiratory tract pathology in habitual users of crack cocaine. Here, we describe the histological alterations in the respiratory tract of mice caused by chronic inhalation of crack cocaine. Twenty 2-month-old BALB/c mice were exposed to the smoke of 5 g crack cocaine in an inhalation chamber once a day for two months and compared to controls (n = 10). We then morphometrically analyzed nose and bronchiolar epithelial alterations, bronchiolar and alveolar macrophage cell density, alveolar hemosiderin content, and in addition determined the vasoconstriction index and the wall thickness of pulmonary arteries. The serum cocaine level was 212.5 ng/mL after a single inhalation. The mucus content of the nasal epithelium increased in crack-exposed animals, and the nasal and bronchial epithelium thickness decreased significantly. The alveolar hemosiderin content and the alveolar and bronchiolar macrophage cell density increased in animals exposed to crack. The vasoconstriction index increased in the pulmonary arteries of the exposed group. Chronic crack cocaine inhalation causes extensive histological changes along the entire respiratory tract.

Pulmonary complications of crack cocaine use: high-resolution computed tomography of the chest

Here, we report high-resolution computed tomography (HRCT) findings in a patient who developed sudden hemoptysis, dyspnea and chest pain after smoking crack cocaine. Chest X-rays showed consolidations, primarily in the upper lobes, and HRCT scans showed ground glass attenuation opacities, consolidations and air-space nodules. A follow-up CT, after drug use discontinuation and administration of corticosteroids, showed partial resolution of pulmonary lesions and the appearance of cavitations. Clinical, imaging and laboratory findings led to a diagnosis of 'crack lung'.

Acute aortic dissection associated with use of cocaine

PURPOSE

Cocaine use can result in a variety of cardiovascular complications, including myocardial infarction, arterial thrombosis, coronary dissection, and cardiomyopathy. Cocaine-induced aortic dissection is uncommon and has been described largely in case reports. The purpose of this study was to review our experience with aortic dissection associated with cocaine abuse.

METHODS

A retrospective chart review was performed of all hospital records during a 15-year period in patients diagnosed with aortic dissection. Among the 164 cases of acute aortic dissection, 16 patients (9.8%) had used cocaine or its derivative, crack cocaine, within 24 hours prior to the onset of symptoms. The remaining 148 patients (90.2%) had no history of cocaine usage. Clinical features, management, and outcome in these two groups were compared.

RESULTS

In the cocaine group, powder cocaine was inhaled intranasally in 11 patients (69%) and crack cocaine was smoked in five cases (31%). The mean duration between cocaine use and the onset of aortic dissection was 12.8 hours (range, 4 to 24 hours). Patients in the cocaine group were younger in age and more likely to have a history of polysubstance abuse than the non-cocaine cohort. In the cocaine group, the incidence of DeBakey dissection type I, II, IIIa, and IIIb was 19%, 25%, 38%, and 19%, respectively. In the group without cocaine use, the incidence of DeBakey dissection type I, II, IIIa, and IIIb was 18%, 23%, 39%, and 20%, respectively. Surgical intervention for aortic dissection was performed in 50% of the cocaine group and 45% of the non-cocaine group. In patients who underwent surgical repair, greater pulmonary complications occurred in the cocaine group than the non-cocaine group (n = 0.02). No difference was noted in the hospital length of stay or 30-day operative mortality among the two groups.

CONCLUSIONS

Cocaine-associated aortic dissection occurs in predominantly male patients with illicit drug abuse who were younger than patients with aortic dissection without cocaine use. Greater pulmonary complications can occur in patients with cocaine-related aortic dissection following surgical interventions.

Pulmonary complications from cocaine and cocaine-based substances: imaging manifestations

Cocaine is the illicit drug whose abuse most often results in cardiopulmonary symptoms and emergency treatment. Habitual smoking of alkaloidal cocaine ("freebase," "crack") has replaced nasal insufflation as the most common method of abuse. Smoking of cocaine exposes the lung directly to the volatilized drug as well as to the other combustion products of the smoked mixture, thereby increasing the risk of adverse pulmonary effects. A wide variety of pulmonary complications including interstitial pneumonitis, fibrosis, pulmonary hypertension, alveolar hemorrhage, asthma exacerbation, barotrauma, thermal airway injury, hilar lymphadenopathies, and bullous emphysema may be associated with the inhalation of crack cocaine or of associated substances such as talc, silica, and lactose. Cocaine abuse represents one of the most serious medical and social problems of our time. Radiologists should be familiar with the various pleuropulmonary complications associated with the abuse of illicit drugs in general and of cocaine in particular to ensure correct diagnosis and appropriate treatment planning in patients with respiratory manifestations associated with such abuse.

Alveolar hemorrhage in anti-basement membrane antibody disease: a series of 28 cases

Anti-basement membrane antibody disease is a rare disorder characterized by the presence of autoantibodies binding to the alveolar and glomerular basement membranes, and mediating both alveolar hemorrhage and acute glomerulonephritis. We retrospectively analyzed 28 cases of anti-basement membrane antibody disease with alveolar hemorrhage proven by bronchoalveolar lavage. The median age of patients at diagnosis was 23 years; 68% were male, 89% were active smokers, and 36% were exposed to some other inhaled agent. At diagnosis, 46% had predominant pulmonary involvement with normal initial serum creatinine. Lung function tests disclosed a restrictive ventilatory defect in 28% (n = 11) and hypoxemia (moderate in 29% and severe in 29%, n = 21). Carbon monoxide transfer factor was elevated in only 25% (n = 12). Bronchoalveolar lavage was more sensitive than any other criterion for detecting alveolar hemorrhage. After onset of treatment, new hemoptysis or transient worsening of hypoxemia occurred in 29% but did not affect pulmonary outcome. In contrast, worsening of renal function occurred in 33% and adversely affected renal outcome. At last follow-up (median, 2.6 yr; n = 24), all patients were alive and a complete cure was achieved in 50%. Long-term dialysis or renal transplantation was required in 42%, and 8% had mild chronic renal insufficiency. Last chest X-ray was normal in all cases, and no patient had respiratory insufficiency. All patients with predominant pulmonary involvement at presentation maintained independent renal function. In summary, this cohort was characterized by frequent exposure to tobacco smoking and other inhaled agents, and a constantly favorable pulmonary outcome contrasting with frequent chronic renal failure. Renal outcome was excellent in the subgroup of patients with predominant pulmonary involvement.

[Hemoptysis in a young man]

INTRODUCTION

We describe the development of severe and recurrent alveolar hemorrhage in a 30 year old man. The patient had presented with frank hemoptysis, that recurred after an interval of 4 weeks, associated with dyspnea and severe anemia requiring transfusion. The chest x-ray and CT scan showed bilateral diffuse ground glass shadows. Fibreoptic bronchoscopy confirmed bilateral diffuse bleeding. Investigations for the common causes of diffuse alveolar hemorrhage (immunological, infective) proved to be negative on two occasions. Toxicological examination of the urine during the relapse revealed a significant level of cannabis and a trace of cocaine. The patient repeatedly denied the use of illicit drugs.

CASE REPORT

Because of the general condition of this young patient a lung biopsy was performed by video-thoracoscopy. This showed evidence of diffuse alveolar damage compatible with inhalation of cocaine. Faced with these results the patient admitted that he regularly smoked "improved joints".

CONCLUSION

This clinical observation emphasises that the inhalation of cocaine is a cause of diffuse alveolar hemorrhage particularly in young adults.

Pulmonary effects of illicit drug use

The lungs are at considerable risk from the use of injected or inhaled illicit drugs. The extent and clinical significance of illicit drug induced lung damage is not known completely. Drug use leads to an increase in infectious pulmonary disease, historically in relation to nonsterile injection techniques, and, more recently, in relation to HIV infection and its pulmonary manifestations. Barotrauma related to "smoking topography" or errant injections also represents a real risk of drug use. Although granulomatous disease that involves the pulmonary vasculature and interstitium is probably common in injection drug users, the clinical consequence of such is difficult to estimate. What effect smoked or injected illicit drugs have on short- and long-term pulmonary function also is hard to ascertain. The ubiquitous use of tobacco among users of illicit drugs certainly has confounding effects. Given that illicit drug use is common and that the "popular" drugs of abuse change from generation to generation, the pulmonary physician must remain informed about, and alert for, the effects of drugs of abuse.

The pathophysiology of cocaine abuse

Cocaine is a naturally occurring alkaloid that increases dopamine concentrations in the reward centers of the brain. There has been a marked increase in cocaine abuse over the last two decades. A neuropsychological stimulant, cocaine also reduces somnolence, increases alertness and improves concentration. However, cocaine abuse has many pathophysiological consequences. These fall broadly into four groups: pathology associated with a drug abusing lifestyle, pathology that occurs whilst intoxicated with (but not directly due to) the drug, pathology associated with drug administration and pathology resulting from pharmacological action of the drug. This review provides a detailed description of the physiological, pharmacological, and pathological effects of cocaine, and highlights the forensic and medicolegal implications of cocaine abuse.

Chronic and acute effects of "crack" cocaine on diffusing capacity, membrane diffusion, and pulmonary capillary blood volume in the lung

STUDY OBJECTIVES

To evaluate possible alterations in the diffusing capacity of the lung for carbon monoxide (DLCO) or its components, membrane diffusing capacity of the lung for carbon monoxide (DMCO) and pulmonary capillary blood volume (Vc), in habitual smokers of "crack" cocaine (with or without tobacco) and following the short-term administration of inhaled cocaine base or IV cocaine HCl.

DESIGN

Cross-sectional and longitudinal evaluation of DLCO and its components in smokers of cocaine alone, tobacco alone, and cocaine plus tobacco, and in nonsmokers and ex-smokers. Measurement of possible acute effects on DLCO and its components after experimental short-term administration of IV and smoked cocaine.

SETTING

University and Veterans Affairs hospital research laboratories.

PARTICIPANTS

Convenience sample of habitual smokers of crack cocaine with or without tobacco and matched control nonsmokers and ex-smokers, and smokers of tobacco only.

MEASUREMENTS

DLCO, DMCO, and Vc.

CONCLUSIONS

Neither habitual cocaine smoking in cross-sectional or longitudinal analysis nor the short-term administration of inhaled alkaloidal cocaine significantly affected DLCO or its component parts. In contrast, a clear cross-sectional effect of regular tobacco smoking was demonstrated.