Harve‐Rytsälä H, Ångerman S, Kirves H, et al. - In critically ill patients, normoventilation is important, and end‐tidal capnography during prehospital anaesthesia routinely guides ventilation, on the basis of the assumption of the gap between arterial partial pressure of carbon dioxide (PaCO ₂ ) and end‐tidal carbon dioxide partial pressure (PetCO ₂ ) of nearly 0.5 kPa (3.8 mmHg), researchers explored this topic via this retrospective study of 502 patients (median age was 58 years), with post‐resuscitation (155, 31%), neurological emergencies (96, 19%), intoxication (75, 15%) and trauma (68, 14%) being the most common patient groups. The median of the gap between PaCO ₂ and PetCO ₂ was reported to be 1.3 kPa. Findings indicate the likely inadequacy of end‐tidal capnography alone as a method to achieve normoventilation for critically ill patients intubated and mechanically ventilated in prehospital setting. Therefore, experts suggest the likely usefulness of an arterial blood gas analysis in identifying patients with an elevated gap between PaCO ₂ and PetCO ₂ .