Does detoxification reverse the acute lung injury of crack smokers?

The effect on chronic crack users of a 3 month detoxification programme on lung clearance of inhaled Tc-99(m)-diethylenetriamine pentaacetate (Tc-99(m)-DTPA) aerosol, spirometry and gas exchange was determined in a controlled in-patient clinical treatment setting. Imaging studies were carried out in eight chronic crack users (four crack-only and four crack plus tobacco) before and after the successful completion of the detoxification programme to measure the clearance of inhaled Tc-99(m)-DTPA from the lungs, an index of lung epithelial permeability. Tc-99(m)-DTPA lung clearance, expressed in terms of the biological half-time, T-1/2, was determined from the slopes of the least-squares fit regression lines of the respective time-activity plots. The mean (+/- S.D.) global T-1/2 values of the crack-only (75+/-39 min) and crack plus tobacco users (22+/-10 min) were significantly shorter (P < 0.02 and P < 0.001, respectively) than from the lungs of the non-smoking controls (124 +/- 29 min). This was consistent with increased lung epithelial permeability secondary to crack-related lung injury. The mean global T-1/2 value of the crack plus tobacco users was significantly shorter (P < 0.05) than that of the crack-only users. After detoxification, the abnormally rapid lung clearance became normal in two of the four crack-only users studied, improved in a third and remained unchanged in the fourth, a subject whose T-1/2 value was already normal initially. However, lung clearance improved in only one of the four crack plus tobacco users studied. Faster Tc-99(m)- DTPA clearance was the only impairment found in seven of the eight crack users, the eighth having restrictive lung disease. Crack-related lung injury, reflected by abnormally rapid Tc-99(m)-DTPA lung clearance, may be at least partially reversible after a 3 month period of abstinence from crack.