Effect ofPneumothorax on Pleurodesis Induced WithTalcinRabbits

Objective: Thepurpose ofthisstudy was todetermine ifa smallpneumothorax wouldinfluence thepleurodesis resulting fromtalc instillation. Methods: Sixty rabbits received an intrapleural injection of400mg/kg talcslurry. Onehalf also received 10mL ofairintrapleurally after thetalc. Tenrabbits ineachgroup were killed 2,14, and 28days after instillation. Results: Twodays after theinjection, themean volume ofairintheanimals that hadreceived the airwas 7.5±0.4mL.There was no airpresent inanyother rabbits. Thevolume ofpleural fluid andthepleural fluid glucose, protein, cell count, anddifferential were similar inbothgroups on day 2,while theLDH level was significantly higher intheairgroup(p<0.05). Thedegree ofgross adhesions andmicroscopic fibrosis was similar inbothgroups andincreased withtime. Conclusions: A smallpneumothorax doesnotdecrease theefficacy oftalcpleurodesis inour experimental model. Theseresults suggest that thepresence ofasmall amountofintrapleural air isnota contraindication totalcpleurodesis inhumans. (CHEST 1998; 114:1143-1146)