The ED staff were struggling to intubate an elderly gentleman with hypoxic respiratory failure. This man is a 75 year old non-smoker who has had a NSTEMI at home after an elective laparoscopic cholecystectomy, and went on to develop acute pulmonary oedema which brought him to hospital.

Background is that of rheumatoid arthritis with decreased jaw opening, and C-spine fusion surgery which significantly limits neck extension. The first attempt at intubation did not go as planned; direct laryngoscopy proved fruitless and though the curved-blade videolaryngoscope revealed a nice-looking Grade 1 view, the bougie ended up poking uselessly into every recess other than the larynx, and the whole thing was abandoned after the saturation probe fell off.

With the suxamethonium wearing off, 50mg of rocuronium were administered, and bag-mask ventilation was recommenced. To restore morale, the pulse oximeter was reattached to the cold clammy finger - but the waveform was of poor quality, and the numbers it generated were scoffed at as being depressing and unrealistic ("50% sats? Pull the other one"). It can't be that low, they said; the patient wouldn't have such a vigorous pulse, they would be peri-arrest! After insistent demands from bystanders, an ABG was collected to debunk this theory. Shortly after the arterial sample was collected, the rhythm collapsed into broad complex bradycardia and asystole.

Then the gas came back.

References

Brackett Jr, Newton C., Jordan J. Cohen, and William B. Schwartz. "Carbon dioxide titration curve of normal man: Effect of increasing degrees of acute hypercapnia on acid-base equilibrium." New England Journal of Medicine 272.1 (1965): 6-12.