operating room ( ors ) fires related to anaesthesia ventilator mishaps are extremely rare events , but when they do occur , result in serious and sometimes mortal consequences . cardiac arrest associated with ventilator fire has not been reported in the published english literature . we report a near - fatal incident of cardiac arrest following ventilator mishap and successful revival of a patient who underwent subtotal thyroidectomy . a 65-year - old 60 kg asa grade i female patient underwent subtotal thyroidectomy for diffuse multinodular colloid goiter . pre - anaesthetic check up revealed normal cardiorespiratory systems . all investigations including electrocardiogram ( ecg ) , echocardiography and chest x - ray were within normal limits . routine general anaesthesia was administered and maintained using o2/n2o / isoflurane / fentanyl / vecuronium and ippv with an electrically driven volume - controlled anaesthesia ventilator . during the operation , intravenous fluids were administered based on haemodynamic parameters . at the end of near - completion of surgery , a moderately loud explosive sound this was followed within seconds by the appearance of smoke and an orange flame from the control panel of the ventilator . within minutes , both the smoke and the flame increased significantly and engulfed the ventilator , leading to complete melting of its parts [ figure 1 ] . the patient was disconnected immediately from the ventilator and ventilated with an ambu resuscitation bag . meanwhile , oxygen , nitrous oxide and electric supply of the anaesthesia apparatus and ventilator were disconnected and the fire was extinguished by spraying water . the anaesthetic and surgical teams shifted the patient out of the fire area to another adjacent operation theatre along with the ambu bag . in the or , the patient was reconnected to the monitor and another anaesthesia work station and ventilation was started with 100% oxygen . the approximate time between disconnection of endotracheal tube ( ett ) and ventilation with 100% oxygen was 23 min . meanwhile , we noticed absence of pulse and oxygen saturation with ecg showing tracings of asystole . cardiopulmonary resuscitation ( cpr ) was started and the lungs were ventilated with high flows ( 12 l / min ) of 100% oxygen . following 34 min of cpr and i.v . atropine 3 mg and adrenaline 2 mg ( 1 mg + 1 mg ) , the patient showed return of spontaneous circulation ( rosc ) . thereafter , the patient maintained a heart rate of 110120 bpm , bp 100/70 mmhg and oxygen saturation of 9394% . a 12-lead ecg , serum troponin a , serum electrolytes and abg were obtained to rule out other causes of cardiac arrest , and were within normal limits . once the patient 's circulation was restored and maintained for 1520 min , the remaining part of the surgery was allowed to complete . after the completion of the procedure , the neuromuscular blockade was antagonized with neostigmine 3.0 mg and glycopyrrolate 0.4 mg . she was observed and monitored in the post - anaesthesia care unit ( pacu ) for 24 h and then discharged on the fifth post - operative day . she was followed - up after 2 weeks and later monthly with no reported adverse sequelae of the event . the incident was notified to the manufacturer of the ventilator and is under an investigation stage to determine the cause of the incident . among all or fires , equipment - related fires are extremely rare incidents , probably because of strict electrical safety standards , good design of equipment and routine inspection and preventive maintenance . however , when these occur , the consequences are often disastrous for both the patient and the or personnel , particularly in poorly equipped hospital set - ups . historically , or fires or explosions caused by anaesthesia equipment were attributable to flammable anaesthetic agents.[25 ] berry et al . have reported combustive destruction of the anaesthetic circuit expiratory valve and explosions within the anaesthesia machine were reported by castro et al . normally , they create some smell or vapors , and these are controlled by stopping the flow of electricity to the device . sometimes , the fire can flare up without these warnings , as noted in our case . to cause fire , an oxidizing agent , a source of heat and a flammable material or fuel must be present . in the present case , sparks due to friction or electrical short circuit might have acted as the source of the ignition , which led to fire and explosion in the oxygen - rich environment . fire mishaps in ventilators are prevented by routine pre - use checkups and device service as per minimum standards mentioned in the user manual . cardiac arrest following ventilator fire is also a rare incident . because this mishap occurred intraoperatively , the first priority was to immediately shift the patient out of the danger area to protect from further thermal damage . although we disconnected the patient from the ventilator immediately , some smoke - rich gases were delivered by the ventilator . as other causes of cardiac arrest were ruled out , we suspected carbon monoxide toxicity as one of the causes for severe hypoxaemia and cardiac arrest . although cooximeter analysis helps in the estimation of carboxyhaemoglobin ( cohb ) , it is not routinely available in sub district - level hospital set ups . the half - life of cohb is between 4 and 6 h with room air , which further drops to 4090 min and 1530 min if the patient is receiving normobaric 100% oxygen and hyperbaric oxygen , respectively . although hyperbaric oxygen is the treatment of suspected co poisoning , high - flow normobaric 100% oxygen can still be life saving . timely and effective resuscitation helped us to revive the patient successfully . in conclusion , ventilator fires , although infrequent , can be disastrous . although the patient did not suffer thermal injury , the or team should be prepared to handle any eventuality arising out of such disaster . prevention of fires requires attention from everyone in the or to hospital authorities who make purchasing decisions . the knowledge and vigilance of the or teams in preventing fire and a quick response during such incidents appears a necessity . having a stringent quality control and ensuring electrical safety of medical equipment