Alveolar Accumulation/Concentration of Nitrogen During Apneic Oxygenation With Arteriovenous Carbon Dioxide Removal

作者：Nielsen Niels D^*; Andersen Gratien; Kjaergaard Benedict; Staerkind Mette E; Larsson Anders

来源：ASAIO Journal, 2010, 56(1): 30-34.

DOI：10.1097/MAT.0b013e3181c4e935

In a model of acute lung injury (ALI), previously, we have shown that apneic oxygenation, using an inspiratory O(2) fraction (F(i)O(2)) of 1.0 combined with extracorporeal arteriovenous CO(2) removal (AO-AVCR) maintains adequate arterial O(2) and CO(2) levels for a prolonged period. However, it is important that F(i)O(2) lower than 1.0 can be used to avoid possible pulmonary oxygen toxicity. In preliminary studies, arterial oxygenation decreased to extreme low levels, when F(i)O(2) < 1 was used in apneic oxygenation. We assumed that this was caused either by alveolar accumulation/concentration of N(2) or by absorption atelectasis. In four anesthetized and mechanically ventilated pigs, mild lung injury was induced. After a lung recruitment maneuver, we initiated two 20-minute periods of AO-AVCR with F(i)O(2) of 1 and 0.5, respectively. By using F(i)O(2) = 1, P(a)O(2) remained above 300 mm Hg. At the end of the period, the alveolar O(2) fraction (F(A)O(2)) was 0.89 (0.88-0.89; median and ranges). With F(i)O(2) = 0.5, P(a)O(2) decreased 90% compared with baseline values and F(A)O(2) decreased to 0.07 (0.06-0.07). No atelectasis was visible on computed tomography after either period, and we, therefore, conclude that the alveolar hypoxia was caused by the alveolar N(2) accumulation/concentration and subsequently by the O(2) depletion. ASAIO Journal 2010; 56: 30-34.

• 出版日期2010-2