Explosion & Fire Safety in

Operation theatre

Moderator: Dr Jesni Joseph

Speaker: Dr Gagan Brar

Contents

• Fire triad

• Products of combustion

• Prevention

• Management– Type of fire– Fire safety education

FIRE TRIAD

• Fuel• Oxidizer• Source of heat/ ignition

Must be present simultaneously & in correct proportions

So, fires can be prevented/ controlled by removing any one of these elements

Typical coexisting ingredients that could cause an OR fire

Products of combustion

• Depend upon: – Temperature of fire– Nature– Proportions of the fuel & oxidizer

• Complete combustion: water, CO2, other oxides

• Incomplete combustion: variety of by products

Products of combustion

• Specific combustion products: PVC, silastic, plastics (produce acids such as HCl & hydrogen sulphide, cyanides, CO & phenols)

Potentially hazardous

Pulmonary toxicity of

combustion products

Consumption of oxygen by fire

Reduced oxygen availability, d/t CO

PREVENTION

MOST EFFECTIVE METHOD

Keep the elements of FIRE TRIAD separated

Follow basic Laser & Electrical safety guidelines

Minimize presence of flammable materials

Sources of Heat & Ignition

• Electrosurgical units– Audible warning tones (shouldn’t be

disabled)– Foot switches should be assigned; &

disconnected when not in use– Placing probe in insulated, non flammable

Holster

Sources of Heat & Ignition

• Cardiac defibrillators– Electrodes to make direct contact without

intervening wires, linen, clothing– Alcohol or alcohol soaked pads, nitroglycerine

patches, ointments should never be used as conducting medium

Sources of Heat & Ignition

• Laser: Energy source; very high power density– Incidentally pressing the laser control

trigger, tissue damage outside the surgical site

– Drape fire– Eye (patient or other medical staff)– Endotracheal tube fires

Endotracheal tube fires

• Direct laser illumination

• Reflected laser light

• Incandescent particles of tissue blown from the surgical site

Prevention

• Reduce the flammability of the endotracheal tube

• Use of Laser resistant ET tubes

• Use Venturi ventilation

• Use intermittent apnea technique

Sources of Heat & Ignition

• Electrical fires in anesthetic monitors have been reported

• NaCl contamination of the interior of monitors resulted in electrical short circuits which led to over heating & ignition of monitors

Fuel

• Flammable anesthetic agents• Flammable disinfecting & degreasing

solutions: alcohol & acetone, must evaporate & fumes eliminated before surgery begins

• Surgical drapes & dressings free of disinfectants

Fuel

• Tissue contents such as bowel gas• Contains: hydrogen + methane• Laparoscopy: insufflation with air• Colonoscopy• Preventive measures

– Unprepared colon is discouraged– Low residue diet– Pre op fasting for 12 hrs

Fuel

• Electrosurgery in airway: Dangerous– ET tubes, oesophageal steth, nasogastric tubes

PVC inflammable with high oxygen conc.

• Preventive measures:– Lowest power for cautery– Bipolar cautery– Helium- oxygen mixture– Jet ventilation without tracheal intubation– Laser resistant ET tubes

Fuel

• Forced air patient warming blankets: Once ignited rapid combustion (fuel source: drape material, oxidizer: forced air)

Oxidizer

• Decrease escape of oxygen & nitrous oxide• Lowest inspired oxygen conc. that ensures

adequate oxygenation, to minimize O2 accumulation

• Selective use of supplemental oxygen• Avoid use of ESU in and around trachea &

pharynx• Addition of inert gases (He) to O2

MANAGEMENT

TYPES OF FIRE

• Class A: wood, paper, cloth & most plastic

• Class B: flammable liquids & grease

• Class C: fire involving electricity

Fire blanket

Water CO2 Dry chemical

Halon

Type of fire Small class A

Class A/ some B

Class B/C small A

Class A/B/C

Class A/B/C

Mechanism Interrupts oxd

Interrupts oxidation, disperses heat

Interrupts oxidation, disperses heat

Interrupts oxidation, disperses heat

Interrupts oxidation, disperses heat

Notes Inexpensive, non toxic

Heavy bulky devices, risk of electric shock

Heavy bulky devices

Leaves residue, damages equipments, ? toxicity

Small, light, no residue/ toxicity

Use of Fire Extinguishers

• PASS:– Pull the Pin to activate– Aim at the base of the fire– Squeeze the trigger– Sweep the extinguisher back & forth

across the base of fire

Fire safety education

• Activation of alarm & communication system

• Location & use of fire fighting tools

• Management of small fire, to prevent spread

• Appropriate responses when fire spread beyond control

Fire safety education

• When & how to evacuate a room, even when it is crowded with equipments & people

• Appropriate routes to take for evacuation, esp when smoke/ flames block normal entry/ exit

• Location of ‘safety zones’ inside & outside the building where patients/ personnel can be evacuated

Summary

• Fire triad

• Prevention: Keep them separated

• Management: Depends on type of fire

• Safety education for all

Fuel

Oxidizer

Source of ignition

Responding to FIRE

• RACE: – Rescue

– Alarm

– Confine

– Extinguish