Content area
Full Text
Intensive Care Med (2009) 35:14841487DOI 10.1007/s00134-009-1513-5 PHYSIOLOGICAL AND TECHNICAL NOTES
Alberto Zanella Nicol Patroniti Stefano Isgr Mariangela Albertini Marco Costanzi Federica Pirrone Vittorio Scaravilli Beatrice Vergnano Antonio Pesenti
Blood acidication enhances carbon dioxide removal of membrane lung: an experimental study
A. Pesenti ())
Department of Experimental Medicine (DIMS), University of Milan-Bicocca, Via Cadore 48, 20052 Monza, Italy e-mail: [email protected] Tel.: ?39-039-2333291Fax: ?39-039-2332297
Abstract Purpose: Extracorpo-real CO2 removal is an effective procedure to allow a protective ventilatory strategy in ARDS patients, but it is technically challenging due to the high blood ow required. Increasing the CO2 transfer through the membrane lung (ML) may lower the demand of extracorporeal blood ow and consequently allow for a wider clinical application of this technique. Since only the dissolved CO2 (5% of the total CO2 content) is easily removed by the ML, we tested whether acidifying the blood entering the ML to convert bicarbonate ions towards dissolved CO2 could enhance the CO2 transfer though the ML. Methods: Six pigs were connected to an extracorporeal circuit comprising a ML. The extracorporeal blood ow was 500 ml/min, while the gas ow was 10 l/min. A 15-min
continuous infusion of 0.5 N lactic acid was added to the extracorporeal blood ow before the ML at a rate of 1, 2 and 5 mEq/min. Between steps we waited for a reequilibration time of at least 30 min. Results: Acid infusion at 0, 1, 2 and 5 mEq/min increased pCO2 (56.19 7.92,68.24 11.73, 84.28 11.17 and 136.66 18.46 mmHg, respectively) and decreased pH (7.39 0.05,7.30 0.05, 7.20 0.05 and6.91 0.05, respectively). ML CO2 removal increased 11, 23 and 70% during acid infusion at 1, 2 and5 mEq/min, respectively. Conclusions: Blood acidication at the inlet of a ML with infusion of 1, 2 and 5 mEq/min of lactic acid can increase the CO2 removal capacity of the ML up to 70%.
Keywords Extracorporeal CO2 removal (ECCO2R) Ventilator-
induced lung injury (VILI)
Lactic acid Acute respiratory
distress syndrome (ARDS)
Extracorporeal life support (ECLS)
Received: 3 February 2009 Accepted: 29 April 2009 Published online: 16 June 2009 Springer-Verlag 2009
The procedure described here is part of a blood processing technique for which patents are pending, International Patent Application: PCT/EP 2008/003661, 7 May 2008 and Italy: MI2007A000913, 7 May...