Dr. A conducts preoperative assessment checked into surgery by Ms. KMrs. Bromily assures Ms. K her fused vertebre will not be a problem intravenous cannula inserted into Mrs. Bromily general anesthesia induced with remifentanil and propofola rapid anesthetic agent laryngeal mask fails 2 nd dose of propofol to counter jaw tension attempt to insert size 3 laryngeal mask fails decision made to use laryngeal mask routine monitoring setup: blood pressure cuff, ECG, pulse oximeter 8:30 pulse rate 81 bpm oxygen saturation 98% no preoxygenation recordednothing recorded on chart 8:35 cannot open Mrs. Bromily's mouth attempt to insert size 4 laryngeal mask fails seven minutes in – first attempts with laryngeal mask IDS score: 4 evidence that situation was not being monitored

8:37 Mrs. Bromily turns blue oxygenation at 75% heart rate increase 8:39 oxygen deteriorates to 40% 8:41-8:43 oxygen still at bottom of chart heart rate down to 69bpm trending to 40 declared can't intubate can't ventilate joined by Dr. B atropine and suxamethonium administered to counter low bpm and allow intubationDr. A attempts intubation 8:45 no visual of voicebox, Carmack rating of 4; oxygen still off chart; heart rate up from atropine attempt is unsuccessful Mr. E and other staff enter to assistmultiple attempts with full assistance failed ventilation attempt with facemask failsventilation attempt with oral airway fails seventeen minutes in – continue ventilation / intubation attempts IDS score: 13+ failed attempt to revise

tracheostomy set brought in successful insertion of laryngeal mask further attempts at intubation and laryngoscopy fail 8:47-8:50 Dr. B attempts to use fiber optic scope and fails due to presence of blood Mr. E also attempts bougie and fails 8:51-8:55 oxygen off the bottom of the chart pulse at 133bpm Mr. E attempts intubation and laryngoscopy and fails 8:55 oxygen off the chart pulse at 133bpm twenty minutes – multiple intubation techniques IDS score: 17+ failed attempt to revise missed opportunity to revise? may have been too late already... was Mr. E beginning his attempt already? failed attempt to revise

9:10 steroids administered to protect from hypoxic brain damage 9:00 oxygen up to 90% blood pressure and heart rate up 9:03-9:09 oxygen unstable dipping down to 49% never above 90% attempt to insert tube with fiber optic scope fails attempt to insert tube blindly fails attempting to awaken Mrs. Bromilyprocedure abandoned 9:13-9:29 breathing begins; oxygen back to normal; blood pressure high; heart rate high Mrs. Bromily taken to recovery fifty minutes in – post ventilation intubation attempts final IDS score: 19+ failed attempt to revise

missed opportunity to revise failure to recognize gravity of situation 9:30 pulse 120 bpm; respiratory rate 20 bpm; blood pressure 84/33 mmHg; temperature 30.1 C; oxygen 95% Mrs. Bromily admitted to recovery unconscious Dr. A informs recovery staff that there were complications and Mrs. Bromily may be slow to wakeDr. A moves on to another patient Mrs. Bromily shows signs of cerebral irritation Mrs. Bromily taken to intensive care 11:00 unstable condition Mrs. Bromily never recovered Dr. A unavailable to help final hours

Reactions At first glance the case seems to be an example of fixation Digging deeper reveals multiple attempts at revision Application of IDS to time line makes level of crisis salient Lack of monitoring apparent from report Report infers poor situation awareness among group Brief time line prohibits any additional cognitive effort cognitive workload already high tracking and treatment of pulse, blood pressure, oxygenation actions occur simultaneously and continuously Recommendations When possible use awake fiber optic intubation Improve salience of crisis scenario Modify oximeter to display measurements below 40% Modify oximeter display to make time below critical level salient Incorporate better monitoring in the OR Some form of tracking: manually on paper; via cameras and mics; verbalizations recorded and transcribed speech to text