Effect Of Laser Smoke On The Bronchopulmonary System Histopathological And Electron Microscopical Study:

Magdi Moussa El-saeed Zarie

Lasers especially the C02 laser are now widely used in surgery,but a little data are available for the effects of the plume (vapor) byproductsresulting from laser surgery.Many researchers have suggested that the smoke is extremelyhazardous to the patient and the surgeons or operating roompersonnel. Some of them were suggested that the laser vapor mighttransmit viruses e.g.• Human papilloma virus (HPV), intact HPV DNA wasdetected in vapor of C02 laser smoke.• Human immunodeficiency virus (HfV) DNA was alsopresent in the laser smoke as a result of vaporization ofconcentrated tissue culture pellets infected with mv byC02 laser.• Viable bacteriophage particles were detected as a result ofvaporization of an agar substrate containing high titres ofbacteriophage.• Laser Smoke was capable of disseminating viable tumortissue at least locally is an air born fashion, but other studywas suggested that viable cells was unlikely present in thelaser smoke.The smoke particles of laser were found. to be mutagenic tosalmonella typhi. strain. Also, bacterial dissemination may occursas a hazard of the laser smoke. Others suggested that the lasersmoke may be hazardous to the respiratory system, the smoke maylead to deposition of the fine particulate matter in the alveoliresulting in from extensive pathology. The laser smoke may alsolead to decrease in the arterial POz, mild hypoxia and depressedtracheal mucus velocity.In our study we try to find an answer to the questionconcerning the hazardous effects of the COz laser smoke on thebronchopulmonary system. We use twenty rabbits of the samespecies divided into five groups (four rabbits each) and exposed tothe COz laser smoke for different periods of time the 1st group wasexposed the COz laser smoke for 10 minutes, the 2nd group wasexposed the COz laser smoke for 20 minutes, the 3rd group wasexposed the COz laser smoke for 30 minutes, the 4th group was thechronic group of exposure to the COz laser smoke for 3-4 weeksand 5th group was the control group.We use a glass chamber measuring 15 cm wide X 25 em lengthX 12 em height. The smoke was obtained by vaporization of humantonsils by the use of COz laser apparatus at a power of 4 watts and200 HZ frequency.The rabbits were sacrificed at different periods of time thendissection of the respiratory system of rabbit was done andexamined electron microscopically & histopathologically. We getthe following results:• At 10 minutes exposure to C02 laser smoke:a- Electron microscopical results :There are massive invasion of lymphocytes, loss of cilia andmicrovilli, sub-epithelial proprial edema, swollen collagenic fibrils,numerous destructed mitochondria, macrophages having phagocyticbodies with various stages of deterioration and the neutrophilshaving large vacuolated granules and smaller specific granules.b- Histopathological results :Pulmonary inflammatory response as an interstitial congestionof the lung tissue, congested blood vessels with edematous thickwall and distended alveolar sacs and ducts.• At 20 minutes exposure to C02 laser smoke:a- Electron microscopical results :There are: Darkly stained pyknotic nuclei, disturbed epithelialcells with destructed cytoplasmic organelles & mitochondria,intercellular irregular spaces, loss of microvilli & apical cilia withdestruction of their apical borders, numerous oesinophilia withphagocytic vacuoles and hypochromatic nuclear lobes, nuclearvacuolation in pneumocyte type II and complete destruction ofmitochondria & endoplasmic reticulum.b- Histopathological results :Interalveolar hemorrhage with hemosidirin deposits, dilatedbroncheoles, lymphocytic aggregation, focal areas of interstitialpneumonia and interstitial congestion with atrophy of some alveolibut dilated others.• At 30 minutes exposure to C02 laser smoke:a- Electron microscopical results :Extruded pyknotic nuclei, destructed cilia of most of trachealcells, numerous number of intercellular lysosomes, irregularlobulated nuclei with abundant euchromatin & fewheterochromatin, interalveolar phagocytic macrophages havingintracytoplasmic phagocytic matter, hypochromatic nuclei, lesslamellar bodies, sub-epithelial blood capillary surrounded withcollagenic fibrils the cytoplasm of endothelial cell having a lot ofvacuoles and Interstitial hemorrhage inbetween lung alveoli.b- Histopathological results :Detached endothelium with hyalinization swollen wall of bloodvessels with peri-vascular edema, lymphocytic aggregation withlymphoid follicle formation, compensatory emphysema &interstitial pneumonia, thrombosed pulmonary capillaries,desquamation of the lining epithelium, intra-alveolar migration ofphagocytic cells and the goblet cells becomes more thin withatrophic changes.• Chronic exposure group to the C02 laser smoke:a- Electron microscopical results :Dividing basal cells while the other cells reveals pyknoticnuclei, sub-epithelial dividing cell with abnormal mitochondria, anabnormal goblet cell having destructed vacuolated nucleus, aspecial type of destruction to the nuclei in the form of boundaryvacuolation, Some goblet cells having no nucleus due to karyolysisor karyorrhexis, an extruded pyknotic nucleus, complete extrusionmay occur with vacuolated appearance of its place, degenerated,destructed mitochondria and endoplasmic reticulum, Atrophy ofgoblet cells with few mucus granules, peri-nuclear halo formation,irregular pyknotic nuclei with degenerative changes, active septalmacrophages having irregular nuclei with destructed engulfedparticles, intracytoplasmic smoke black granules of variable sizes &shapes, abnormal aggregation of blood platelets, an activefibroblasts which forms new collagenic fibrils, abnormally formedcollagenic fibrils, active macrophage engulfed carbon particles,squamous metaplasia the columnar ciliated epithelium was changedinto flattened ciliated epithelium.b- Histopathological results :We get the following results: emphysema, thickened bloodvessel walls with hyaline degeneration, abnormal chondrocytes,lung collapse & fibrosis, hyalinization of broncheoles & bloodvessels and metaplastic changes in the form of :• The endothelium showing patchy areas of perpendicularendothelial cells.• Stratification of endothelium.• Beginning of metaplastic changes of epithelial lining ofbroncheoles.• Blebs protrusions in the apical border of most upper cells ofmetaplastic epithelium in the trachea .• Statistical Results :The following significant data were verified:In electron microscopical study:Nuclear changes .Cell division, nuclear vacuolation, extrudednuclei, nuclear destruction, pyknotic nuclei & hypochromatosis.Cellular changes .lymphocytosis, loss of cilia & microvilli,destructed mitochondria, active fibroblasts, abnormal collagenicfibres, smoke granules, increased intracellular lysosomes, gobletcell atrophy, squamous metaplasia & blood capillary roughness.In histopathological study:The following significant data were observed:Emphysema, thrombosed pulmonary capillaries & arterioles,metaplastic changes, lymphocytic aggregation, hyalinization ofblood vessel walls, inter-alveolar hemorrhage, interstitialcongestion, destructed cilia, atrophic thin goblet cells, interstitialfibrosis, phagocytic cell migration and desquamation of epithelialcells.On Conclusion :Laser plume is considered as one of the complications of thesurgical laser procedures. So, we must provide two suction set-upsfor all upper aerodigestive tract procedures one to remove smokeand steam from the operative field, the other to remove blood andmucus from the wound. Positioning of the nozzle of smokeevacuator at a distance of two inches from the laser interaction sitewas founded to be adequate.Filters should be used in the suction lines and several smokeevacuation systems must be used to capture emissions from theseprocedures. Also, a special high efficiency masks are required tocatch laser plume particles.