Long-chain versus medium-chain lipids in acute pancreatitis complicated byacute respiratory distress syndrome: effects on pulmonary hemodynamics andgas exchange

Background and Aims: In order to assess the effects of fat emulsions in pat ients with acute pancreatitis and acute respiratory distress syndrome (ARDS ) before the pancreatic injury was complicated by infection, pulmonary hemo dynamics and gas exchange were investigated during the administration of lo ng-(LCTs) or medium-chain triacylglycerols (MCTs). Methods: This prospective trial included nine patients with acute pancreati tis and ARDS: each patient was used as his/her own control. In all cases, t he needle aspiration culture of the pancreas was negative. Fat emulsion pro vided 50% of the energy expenditure. The patients were infused, in random o rder, with pure LCTs and a 1:1 mixture of LCTs/MCTs on days 1 and 2, over a n 8 h period. Results: LCT infusion increased the mean pulmonary artery pressure (MPAP) f rom 28 +/- 5 to 35 +/- 3 mmHg, pulmonary venous admixture (Qva/Ot) from 26 +/- 5% to 36 +/- 5% and decreased arterial PO2(PaO2)/fractional inspired ox ygen (FIO2) from 210 +/- 20 to 170 +/- 20 (P< 0.05). The infusion of LCT/MC T 1:1 emulsions increased oxygen consumption (VO2) from 340 +/- 10 to 398 /- 15 ml/min, cardiac output (CO) from 8.8 +/- 0.2 to 9.5 +/- 0.5 L/min and CO2 production (VCO2) from 247 +/- 12 to 282 +/- 14 mL/min (P < 0.05). Conclusion: LCT/MCT 1:1 mixtures are recommended in cases of acute pancreat itis and ARDS, even though infusion over a short period increases the metab olic demand. (C) 2001 Harcourt Publishers Ltd.