Laser surgery – anesthetic concerns Dr. S. Parthasarathy MD, DA, DNB, Dip Diab.MD,DCA, Dip software based statistics, PhD (physiology)

Some physics !!! laser is an acronym for light amplification by stimulated emission of radiation Electron moves in orbits If electron moves out to the next orbit energy in energy is absorbed –in the form -photon Absorption The reverse is emission

Stimulated emission of radiation

Amplification

Properties Light amplification by stimulated emission of radiation Monochromatic – one wave length Collimated: all waves are parallel to each other and there is no dispersion; Coherent: all waves are in phase and travel together (Electromagnetic fields of photons oscillate synchronous) High intensity and focus – hallmark of LASER

Three essential parts Medium -- source of atoms Gas, liquids, solids Pumping – source of stimulating photon Mirrors -- channelize Tissue penetration depends on which laser Eyes, skin or deep !!

Why do we need this quantum physics principle in surgery ?? Precise location- delivery of thermal energy Hemostasis Tissue dissection Selective absorption Pass through endoscopes Less damage to adjacent tissues – less edema – less post op pain

Clinical uses Derm – CO2- Excision of thermal eschars hemangiomata,keratosis, telangectasia, spider nevi, basal cell ca, malignant melanomas Argon- tatoos General surgery - CO2- Splenectomy, breast lump excision, gastrectomy, mastectomy

Clinical uses O & G : Excision of cervical, vaginal, and vulvar neoplasias- benign vaginal adenosis, condyloma Neuro : Excision of benign brain tumors, neuromas Ophthal: Glaucoma, RD, diabetic proli. Retina ENT : Tympanoplasty, rnyringotomy, stapedectomy Excision of laryngeal and tracheal papillomas vocal cord polyps, nodules, keratoses

Hazards of LASER

Rare

Plume The interaction of laser with tissue produces a plume of smoke and fine particles (0.1– 0.8 μm) which can deposit in the alveoli, interstitial pneumonitis, bronchiolitis, reduced mucociliary clearance, emphysema have mutagenic potential Normal mask 3 μm– high protection mask !!

!! Plume problem !! Burn 1 gm tissue = 3- 5 cigarettes Smoke evacuators – must

Laser lap surgeries Laser prostate Laser tracheal tumours Gas embolism reported

Danger to organ and vessel Vessels greater than 5mm diameter will not be coagulated by laser. Pneumothorax has occurred with laryngeal procedures. Burn depth is difficult to assess with Nd-YAG lasers and perforation can occur days after the surgery when oedema and necrosis peak.

Errant infrared energy from a CO 2 laser can quickly cause a serious corneal injury argon, KTP:Nd:YAG, or ruby lasers may burn the retina The lids of patients’ nonoperated eyes should be taped closed and then covered with an opaque, saline-soaked knit or metal shield OK

Airway fires 6 airway fires in 4416 cases 0.1 – 1 % incidence Primary Secondary to tissue injury

Anaesthetic concerns Many cases We are not called They do it alone !!!

General safety measures Eye shields for OR personnel Wave length specific glass inserts on windows and doors Signs identifying laser use Drapes and towels – cloth with high porosity / wet Fire extinguisher, water bucket

General safety measures Protection of eyes, nose, moustache/ beard No eye ointments / No metal eye cups No plastics Cloth adhesive tape/ Wet with high porosity Avoid tincture benzoin ??!! Tissue cleansing agents should be wiped off

General safety measures All persons should be aware of areas of laser use, and controlled access to these areas must be maintained Saline moistened towels near the exposed area Eye protection for all dull, non reflective, or matte-finished instruments Endoscope – light 1 cm distal to the tip. Knowledgeable personnel Papilloma excision – cross infection to OE staff ??.

Airway surgery !!!

What should we do ?? Maintain Oxygenation Allow removal of CO2 Keep patient anesthetized Reduce incidence of airway fire by special approaches To deal with crisis Reduce post operative complications

Premedication with narcotics,diazepam, and even barbiturates promote tongue and jaw relaxation and respiratory depression and should be avoided in patients with compromised airways. Preop airway assessment Fibre optic, tracheotomy – decide Not detailed now.

Intubation Or no intubation Advantages secured airway ability to monitor ETCO2 and O2 conc. decreased risk of soiling the distal airway Disadvantages risk of an ETT fire, high AWP high resistance with spontaneous ventilation difficulty in suction

Special tubes those are laser resistant. Wrapping standard tubes. Cuff of ETT has to be inflated with saline+methylene blue to ignite PVC tubes seconds red rubber tubes seconds

Laser-Shield II Tube is made from silicone with an inner aluminum wrap and an outer Teflon coating Cuff with methylene blue. Unprotected yellow – wet cottonoids Cuff puncture – recognize - color Place the cuff distal most-- Cotton moist pledgets

Laser flex stainless steel tube with a smooth plastic surface and a matte finish to reflect a laser beam Two cuffs – one goes off, the other will take care. Stiff rough surface – some videoscopes ??

Sheridan Laser Tracheal Tube Radiopaque pledgets that are designed to be moistened and placed above the cuff are provided with each tube red rubber tube wrapped with copper foil tape. overwrapped with water- absorbent fabric that should be saturated with water prior to use. There is a copper band at the cuff-tube junction. f a b ri c

Lasertubus white rubber and has a cuff-within-a-cuff design Inner cuff – air Outer cuff –saline Silver foil and saline soaked sponge over it.

The Bivona Fome-Cuf laser tube has an aluminum and silicone spiral with a silicone covering The Norton tube is a reusable, flexible, spiral- wound metal tube with a stainless steel connector and thick walls Vigilant anesthesiologist What is needed

WRAP Minimal adhesive Aluminium foil From proximal cuff % cover Include the inflation channel,Till proximally - cover cuff with moist gauze - methylene blue in saline for cuff inflation

shield material adds almost 2 mm to the diameter of the endotracheal tube !! Rough edges can injure the pharyngeal and laryngeal tissues. Pieces of tape can Loosen break off, and be aspirated Cuff ?? Copper and aluminum – arts and crafts shops, radio shops !!

Using different modes of ventilation Venturi jet ventilation by metallic Cannula Both ends open Entrains air IV maintanance Relaxant – yes Trans cutaneous CO2 monitor ??

Intermittent ventilation Put the ET tube Ventilate Take it out Use laser – stop laser Put it back !! 7 min,93 % SaO2, BP changes, rhythm change 100 % oxygen + iso --- no sevo – short acting – relaxant – yes No risk of fire but oxygenation and ventilation ??

High frequency Transtracheal HFJV Subglottic/Translaryngeal HFJV Supraglottic superimposed HFJV No nitrous and FiO2 around 25 %

Preop tracheostomy done !! tracheostomy – tube removed --laser resection - through the stoma- ventilation during laser resection – problem Inspiration via jet ventilation through vocal cords -Exhalation through tracheosomy stoma Do we have metal tubes of small size ?? Small child – spontaneous GA – TUBE through stoma

Post op period extubated in the operating room whenever possible. The ET tube is inspected to ascertain that all the adhesive wrapping is intact. If tape is missing, laryngoscopy and bronchoscopy are performed. Laryngospasm and pneumothorax – beware

Post op Steroids Nebulized adrenaline Heliox with 21 % oxygen !!?? Airway equipment and personnel knowing equipments

What matters ??

The three – matters Ignition source – laser Switch off – lowest possible, Material – ET tubes Dry till spirit goes off, moisture into fields Environment – Oxygen – suction oral cavity if O2 > 30 %

Airway fire protocol 1. Remove the tracheal tube, - another team member extinguish it. Remove cuff-protective devices and any segments of burned tube that may remain smoldering in the airway. Mild – reintubation difficult - pour saline with tube in situ ?? Then remove 2. Stop the flow of oil gases to the airway. 3. Pour saline or water into the airway.

For the patient !! Reestablish the airway, and resume ventilating with air until you are certain that nothing is left burning in the airway, switch to 100% oxygen. Examine the airway to determine the extent of damage, and treat the patient accordingly.( Xray, CT,ABG etc,) Save involved materials and devices for later investigation.

Summary LASER –physics Medium, stimulation, mirrors Surgeries, complications Types of anesthesia -- intubate or no!! Safety measures Protocol

Thank you all !!