Les seuils d’anémie, d’hypoxie et d’hypercapnie. Leçons à tirer des limites physiologiques chez les patients gravement malades

Abstract

Physiological alterations occur in the critical care medicine and reflect illness. Rendering patients physiologic parameters in the range that is normal for the population is not necessarily good; it may be frankly harmful. We do not currently possess outcome-based tools that allow us to titrate physiological parameters and ensure improved outcome. It is highly unlikely that our practice will evolve to inducing anemia, hyperthermia, hypoxemia, hypercapnia and hypotension in our critically ill patients! However, evolving knowledge of the appropriate thresholds for these parameters in critically ill patients, in addition to greater understanding of the potential iatrogenic illness associated with parameter 'normalization', could lead to provision of enhanced patient care. In the coming years it is possible that we will redefine the 'normal' range for common clinical and laboratory values relating to the critically ill. We may switch to 'context sensitive' interpretation of parameters of illness, and manage critically ill patients accordingly.

“Therapeutic Hypercapnia” after Ischemic Brain Injury

“…Increased arterial carbon dioxide levels have been associated with beneficial effects after experimental brain injury in the past. [2][3][4] The effects of mild respiratory acidosis in prevention as well as recovery from organ system damage have previously been studied in the heart, lung, and immune systems, [5][6][7][8][9] and permissive hypercapnia is part of today's clinical practice of low tidal volume ventilation to improve the outcome of patients with acute lung injury. 10 Interestingly, the current American Heart Association Guidelines recommend 12-15 breaths/min during cardiopulmonary resuscitation and stress the potential negative role of inadvertent hyperventilation on survival.…”

Respiratorische Insuffizienz verursacht durch nicht-pulmonale Funktionsstörungen

“…Insbesondere akut auftretende Anämien, z. B. im Rahmen von Blutungen, gehen in hohem Maße mit pulmonalen Komplikationen und einer hohen Mortalität einher [10,26].Weiterhin muss den hämolytischen Anämien im Hinblick auf die Ausbildung einer akuten respiratorischen Insuffizienz Beachtung geschenkt werden. So kommt es z.…”