The document discusses lasers and their applications in anaesthesia and surgery. It provides a brief history of lasers, explaining their basic physics and properties. It describes different types of lasers used in medicine like CO2, Nd:YAG, and argon lasers. It discusses biological effects of laser light and various clinical applications of lasers. It also outlines safety considerations for lasers, including protection of the eyes, endotracheal tube fires, and protocols for managing laser-related hazards and emergencies.

1. LASERS AND ANAESTHESIA Dr.P.Narasimha Reddy, Professor, Dept of Anaesthesiology, Narayana medical college, Nellore.

2. Laser printer Laser pointer Laser: everywhere in your life

18. How a laser works?

19. 1. High-voltage electricity causes the quartz flash tube to emit an intense burst of light, exciting some of Cr 3+ in the ruby crystal to higher energy levels. 2. At a specific energy level, some Cr 3+ emit photons. At first the photons are emitted in all directions. Photons from one Cr 3+ stimulate emission of photons from other Cr 3+ and the light intensity is rapidly amplified.

20. 3. Mirrors at each end reflect the photons back and forth, continuing this process of stimulated emission and amplification. 4. The photons leave through the partially silvered mirror at one end. This is laser light.

28. Schematic diagram of a dye laser DYE LASER A dye laser can be considered to be basically a four-level system. The energy absorbed by the dye creates a population inversion, moving the electrons into an excited state.

33. BIOLOGIC EFFECTS OF LASER LIGHT

34. Biological effects of laser CRITICAL TEMP ( 0 C) BIOLOGICAL EVENT 42 Warmed 45 Cell death, edema, endothelial damage 60 Protein coagulation 80 Collagen denaturation 100 Tissue boils 210 Dehydrated tissue burns

36. commonly used Laserlights Laser media Color Wavelength (nm) Typical application Carbon dioxide Far infrared 10,600 General, cutting Ruby Red 694 Tattoos, nevi KTP:YAG Green 532 General, pigmented lesions Argon Green 514 Vascular, pigmented lesions Xenon fluoride Ultraviolet 351 Cornea, angioplasty

42. ARGON LASER

44. COSMETIC LASER SURGERY

45. LASER IRIDOTOMY

46. LASER REVASCULARISATION

47. LASER TO RESHAPE CORNEA

48. LASER SKIN RESURFACING

49. LASER LIPOSUCTION

51. HAIR REMOVAL

52. LASER PLASTIC SURGERY-SAGGING

53. LASER TO MAKE AN INCISION

54. LASER VISION CORRECTION

56. LASER HAZARDS

57. Safety Considerations

69. Various endotracheal tubes for laser airway surgery Type of tube Advantages Disadvantages Polyvinyl chloride Inexpensive, nonreflective Low melting point, highly combustible Red rubber Puncture-resistant, maintains structure, nonreflective Highly combustible Silicone rubber Nonreflective Combustible, turns to toxic ash Metal Combustion-resistant, kink-resistant Thick-walled flammable cuff, transfers heat, reflects laser, cumbersome

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