De Bels et al. Journal of Medical Case Reports 2012, 6:20 http://www.jmedicalcasereports.com/content/6/1/20 Table 1 Comparison of antibody kinetics using different techniques Test (units) MIF-IgGa (titer) MIF-IgMb(titer) MOMP-IgGc (AU/mL) LPS-IgGd (index) LPS-IgAe (index) Day one 1/512 < 1/10 102 1.5 < 0.9 Day 13 1/2048 < 1/10 478 6.8 2.8 Day 23 1/4096 < 1/10 > 500 9.4 1.3 aMIF-IgG (Focus Diagnostics): + when > 1/512 or a four-fold rise in titer in consecutive sera; bMIF-IgM (Focus Diagnostics): < 1/16 = negative; cMOMP-IgG (C. pneumoniae IgG-ELISA plus medac): + when ≥ 28 AU/mL; dLPS-IgG (C. pneumoniae IgG- rELISA medac): + when index ≥ 1,1; eLPS-IgA (C. pneumoniae IgA- rELISA medac): + when index ≥ 1,5; doubtful: index 0.9-1.4. typical for sepsis (hemodynamic values are shown in Table 2). Metabolic data showed a mixed venous satura- tion of 56%. Despite maximal ventilatory support (high positive end expiratory pressure, an inspired oxygen fraction (FiO2) of 1.0, nitric oxide inhalation of 20 ppm, neuromuscular blocking agents and prone positioning), our patient remained severely hypoxemic (PaO2/FiO2 = 38) which led us to initiate ECMO treatment. Venovenous ECMO (a Sorin Revolution centrifugal pump, a Sorin ECCO oxygenator and a Sorin Satcrit console from Sorin Group, Milano, Italy) was put in place on the fifth day of hospitalization, with a left femoral 22-Fr drainage cannula and a right femoral 23- Fr return cannula, inducing a drastic improvement of our patient’s oxygenation parameters (PaO2 = 120 mmHg). The mixed venous oxygen saturation (SVO2) increased from 56% to 86%. Continuous veno-venous hemodiafiltration (CVVHDF) renal replacement therapy was also initiated on day three because of acute renal failure. There were no severe complications of the ECMO treatment except for hemorrhagic suffusion of the two femoral catheter insertion points, requiring a blood transfusion. ECMO and CVVHDF were withdrawn on day 12. Our patient was extubated on day 18 and discharged from Table 2 Hemodynamic values throughout Intensive Care Unit stay till ECMO removal. Day one Day five Day nine Day 12 Parameters HR MAP PCWP CI (3.0-5.0) ISVR (1200-2000) Noradrenaline (μg/kg/min) Dobutamine (μg/kg/min) 97 60 18 3.9 861 1.1 15 88 67 12 4.2 1416 0.6 20 92 69 7 2.7 2414 0.2 5 104 91 6 4.6 1512 0 0 HR: heart rate (beats per min); MAP: mean arterial pressure (mmHg); PCWP: pulmonary capillary wedge pressure (cmH20); CI: cardiac index (L/min/m2); indexed systemic vascular resistance (Dyne.sec.m2/cm 5 ). Page 3 of 6 our Intensive Care Unit on day 20. He went home a month later. He is now in good physical condition and has returned to work and to a normal social life. Discussion This case illustrates the polymorphism in the presenta- tion of C. pneumoniae infection, which can cause severe CAP complicated by ARDS, even in immunocompetent patients. Pneumonia and bronchitis are the most com- mon clinical infections associated with C. pneumoniae. The classical pulmonary presentation is a single subseg- mental infiltrate, even though lobar consolidation or bilateral infiltrates can also be seen. Two major aspects are discussed below: the rationale for the use of ECMO in ARDS patients as well as its dif- ferent techniques, and the difficulties of diagnosing C. pneumoniae pneumonia. ECMO and CO2 removal There are two main ECMO techniques according to the type of vascular access that is used: venovenous and venoarterial. Each one has a specific indication. Venoarterial ECMO gives cardiac and respiratory support. Indications for venoarterial ECMO include postcardiac surgery (heart surgery or heart trans- plantation), cardiogenic shock due to acute myocar- dial infarction or acute myocarditis and intoxication. For cardiac support, the goal is to optimize organ perfusion (by obtaining a SVO2 greater than 70%, which usually needs an output index of about 3 L/ min/m2). This is achieved by choosing the appropri- ate sizes of cannula according to the patient’s body surface area. In isolated respiratory failure, a venovenous access is preferred. The objective is CO2 removal at least equal to the patient’s metabolism (roughly 3 cm3/kg/min in adults). The purpose of venovenous ECMO use in ARDS patients is lung protection (reducing ventilator- induced lung injury) through a decrease in alveolar dis- tention permitted by the reduction in ventilator conditions. Even though a lot of progress has been done in tech- nical issues, the risk-benefit ratio must be taken into account when ECMO is proposed to a patient with severe respiratory failure. As in all extracorporeal devices, anticoagulation is mandatory. Many patients will experience bleeding, which can be very severe. Con- traindication for anticoagulation remains the most important limitation of this technique. Previous severe disability or poor prognosis due to underlying disease constitutes the other main contraindication for ECMO initiation. The main complications are bleeding, throm- boembolism, cannula-related complications, pulmonary embolism or infarction, aortic thrombosis and coronary