1、Anesthesia in Laser Surgery,R1 Minghui Hung Department of Anesthesiology, NTUH,“Never are cooperation and communication between surgeon and anesthesiologist more important than during head and neck surgery.” Morgan, Clinical Anesthesiology,Physics of Laser light (I),Light Amplification by Stimulated
2、 Emission of Radiation Electromagnetic radiation Einstein: all electromagnetic radiation consisted of wavelike quanta called photonsE (J) = h v Wavelength for visible light ranges from 385nm to 760 nm,Physics of Laser light (II),Characteristics: Monochromatic (one wavelength) Coherent (oscillates in
3、 the same phase) Collimated (exists as a narrow, parallel beam) Intense light beams, intense energy to small target sites,Laser system components,Laser system components Light guide,Used as scalpels and electrocoagulators Dermatology, thoracic surgery, ophthalmology, gynaecology, plastics, ENT, urol
4、ogy and neurosurgery,Clinical applications,Laser interaction with tissue,Used as scalpels andelectrocoagulators Precise microsurgery Relative “dry” Less damage to adjunct tissue Less postoperativepain and edema,Common used Laser lights,Atmospheric contamination Perforation of a vessels or structure
5、Embolism Inappropriate energy transfer,Laser Hazards,Plume of smoke and fine particulates (mean size 0.31um) Efficiently transported and deposited in the alveoli Sensitive individuals: headaches, tearing, and nausea after inhalation Animal study: interstitial pneumonia, bronchiolitis, reduced mucoci
6、liary clearance, inflammation, emphysema Prevention smoke evacuator high-efficiency masks,Atmospheric contamination,Misdirected laser energy may perforate a viscus or a large blood vessel Laser-induced pneumothorax Perforation may occur several days later when edema and necrosis are maximal,Perforat
7、ion,Venous gas embolism when laparoscopic or hysteroscopic laser surgery At hysteroscopy, liquid (saline) coolant is the only safe option If coolant gas must be used, CO2 should be considered Continuous airway CO2 monitoring,Venous gas embolism,Incidentally pressing the laser control trigger Tissue
8、damage outside of surgical site Drape fire Eye (patient or other medical staff) Endotracheal tube fires,Inappropriate energy transfer,Incidence: 0.5 1.5 % Source: direct laser illumination reflected laser light incandescent particles of tissue blown from the surgical site,Endotracheal tube fires,Blo
9、wtorch ignition of an endotracheal tube.,Approaches to reduce the incidence of airway fire,Reduce the flammability of the endotracheal tube Use Venturi ventilation Use intermittent apnea technique,Various endotracheal tubes for laser airway surgery,wrapping with moistened muslin coating with dental
10、acrylic wrapping with metallized foil tape most popular approachaluminum foilcopper foilplastic tape thinly coated with metal,Protection of the endotracheal tubes,Cuff wrapping technique,methylene blue stained saline instead of air,No cuff protection Adds thickness to tube Not an FDA-approved device
11、 Protection varies with type of metal foil Adhesive backing may ignite May reflect laser onto non-targeted tissue Rough edges may damage mucosal surfacess,Disadvantages of wrapping,Oxygen and nitrous oxide are powerful oxidizers Reduce FiO2 to minimum concentration Helium may benefit as a diluent ga
12、s Volatile anesthetics currently used are nonflammable and nonexplosive Pyrolized toxic compounds,Effect of high oxygen and nitrous oxide gas mixture,Norton. spiral wound stainless steel ETT Bivona Fome-Cuff. aluminium spiral tube with a silicone polyurethane foam cuff Xomed Laser-Shield. silicone e
13、lastomer tube containing metallic powder Mallinckrodt Laser-Flex. airtight stainless steel spiral wound tube with two PVC cuffs,Metal endotracheal tubes,Barotrauma Pneumothorax Restriction to only intravenous agents Gastric distention Relative requirement for compliant lungs,Jet ventilation,Intermit
14、tent apnea technique,Hypoventilation Pulmonary aspiration,Remove source of fire (the laser!). Stop ventilating, disconnect circuit, extubate. Extinguish fire in bucket of water (MUST have one ready!). Mask ventilate with 100% O2, continue anaesthesia i.v. Direct laryngoscopy & rigid bronchoscopy for damage and debris.,Airway fires protocol (I),Reintubate if damage. Blowtorch fire may need distal fibreoptic bronchoscopy and lavage. Severe damage may need low tracheostomy. Assess oropharynx and face. CXR. Steroids.,Airway fires protocol (II),I am a sheep.,SHEEP me 2.,We wish you 羊 羊 得 意,
