Case Report

An unconscious man with asthma and a fixed, dilated pupil

Background: Hypercapnic coma is a rare differential diagnosis in the unconscious patient. One underlying mechanism may be hypoventilation due to spontaneous pneumothorax. Although hypercapnia is not a typical finding in spontaneous pneumothorax in patients with otherwise healthy lungs, under certain circumstances, hypercapnia may readily develop. Objectives: We report a rare case of profound hypercapnic coma due to spontaneous pneumothorax after contralateral pneumonectomy. In addition, we review other causes of hypercapnic coma and its outcome and discuss the relationship between arterial carbon dioxide partial pressure and level of consciousness. Case Report: An 85-year-old man without evidence of trauma or intoxication presented unconscious to our Emergency Department. The physical examination and X-ray study revealed a left-sided spontaneous pneumothorax. A right-sided pneumonectomy 25 years earlier had promoted the development of profound hypercapnic coma. After insertion of a thoracic drain, the coma rapidly resolved without any neurological deficit. Conclusions: Although severe hypercapnia is usually due to decompensation of chronic lung disease, pneumothorax potentially may cause hypercapnic coma. Review of the literature suggests that there is no close correlation between arterial pCO₂ (partial pressure of CO₂) levels and the degree of impairment of consciousness; however, levels exceeding 80 mm Hg are likely associated with significantly impaired consciousness. Hypercapnic coma usually resolves without neurological deficit as arterial pCO₂ tensions decline.

Les traitements classiques de l’asthme aigu grave (AAG) sont parfois insuffisants. Le recours à des thérapeutiques de sauvetage, comme l’administration de gaz halogénés, est parfois nécessaire, mais ces traitements restent peu évalués. Nous rapportons le cas d’un patient présentant une hypertension intracrânienne (HTIC) d’origine hypercapnique lors de l’utilisation du système AnaConDa™ ou Anaesthetic Conserving Device™ (ACD) (Sedama Medical). Cette majoration de la PaCO₂ nous semble liée à l’augmentation de l’espace mort, secondaire à l’utilisation de ce dispositif.

Standard treatments against severe acute asthma can be insufficient and need salvation treatments, such as isoflurane delivery. These treatments have not been much assessed and could lead to unrecognized side-effects. We report the case of a young man who suffered from intracranial hypertension associated with severe hypercapnia during the delivery of isoflurane via the system AnaConDa™ or Anaesthetic Conserving Device™ (ACD) (Sedama Medical). The rising of PaCO₂ appears to be linked to an ACD-dependent increase in the dead space.

All patients with asthma are at risk of having exacerbations. Hospitalizations and emergency department (ED) visits account for a large proportion of the health-care cost burden of asthma, and avoidance or proper management of acute asthma (AA) episodes represent an area with the potential for large reductions in health-care costs. The severity of exacerbations may range from mild to life threatening, and mortality is most often associated with failure to appreciate the severity of the exacerbation, resulting in inadequate emergency treatment and delay in referring to hospital. This review describes the epidemiology, costs, pathophysiology, mortality, and management of adult AA in the ED and in the ICU.