De Bels et al. Journal of Medical Case Reports 2012, 6:20 http://www.jmedicalcasereports.com/content/6/1/20 or cerebral hypoxemia; the latter three being more fre- quent in a venoarterial montage type. Discussion still stands in the literature as to whether mechanical ventilation of more than seven days is or is not a relative contraindication for ECMO because of ventilation-induced lung injury [11]. The first randomized clinical trials failed to demon- strate beneficial effect of ECMO for severe respiratory failure in the 1970s and 1980s. Since then, technical improvements for ECMO on one hand, and better treat- ment of the ARDS (protective ventilation and others) on the other hand, have renewed interest in ECMO [12]. The recent CESAR trial (Conventional Ventilation or ECMO for Severer Adult Respiratory Failure [13]) demonstrated a possible beneficial effect of ECMO. Of those patients referred for ECMO, there was 63% survi- val rate at six months without disability, compared to 47% in those who were assigned to conventional man- agement. This translates to one extra survivor without disability for every six patients treated. A recent Italian experience, in patients with ARDS due to the influenza A/H1N1 virus, based on pre-emp- tive patient centralization showed a 77% survival rate if ECMO was started within seven days of initiation of mechanical ventilation [11]. Indication for ECMO in this study was refractory hypoxia or an oxygenation index below 30 despite a PaO2/FiO2 ratio greater than 100 mmHg. Treatment of critically ill patients affected by the 2009 Influenza A (H1N1v) outbreak in Australia and New Zealand [14] included ECMO, with a 71% survival rate at Intensive Care Unit discharge, an excellent result. These three studies emphasize the renewed place of ECMO in the treatment of severe ARDS with very good survival rates, considering the severity of the initial insult. The limitation of plateau airway pressures and the low tidal volume used in ARDS patients have been at the cost of an increased PaCO2. There has therefore been an increase in interest for extracorporeal CO2 removal techniques. Different techniques have been developed but most of them have not gone to relevant, sufficiently powered clinical trials due to technical problems or insufficient CO2 removal or oxygenation [15]. The pumpless extracorporeal lung assist (PECLA), or Nova- lung® [Novalung GmbH, Heilbronn, Germany], is a compact pumpless device driven by the pressure gradi- ent between arterial and venous blood. A femoro- femoral setting is most commonly used. The main advantage of a pumpless device is a reduction in mechanical blood trauma, bleeding and hemolysis. The Novalung® has been widely studied in ARDS. Three stu- dies have demonstrated the clinical efficacy of this PECLA device [16-18]. CO2 removal is efficient but Page 4 of 6 oxygenation may be insufficient in these critically ill patients. C. pneumoniae diagnosis Diagnosis of C. pneumoniae pneumonia is still debated in the current literature. According to Grayston et al. and Saikku et al. [19,20], who first described this Chla- mydia species, almost everybody is infected and rein- fected with C. pneumoniae throughout his or her life. Unspecific symptoms of C. pneumoniae infections make the diagnosis even more difficult, with a possible under- estimation of its frequency. Undetected infections may lead to chronic disease with serious consequences, such as atherosclerotic cardiovascular disease [21] or asthma. Its incidence in CAP ranges from 3% to 22%, varying according to the diagnostic method used [22]. The most frequent routinely used diagnostic techniques are serolo- gical, including complement fixation test, immunofluor- escence assay, microimmunofluorescence (MIF) and genus- and species-specific enzyme-linked immunosor- bent assay (ELISA) systems. No currently available sero- logic tests of a single serum specimen will provide conclusive evidence of a current infection with C. pneumoniae. Since the publication of the Centre for Disease Con- trol (CDC) 2001 recommendations for Nucleic Acid Amplification Tests (NAATs) [23], a multitude of in- house polymerase chain reaction (PCR) tests have been described, though very few of them have been vali- dated by the CDC. Results of NAATs may be unreli- able because of cross-contamination, inappropriate treatment of the clinical samples (leading to the loss of the target nucleic acid) or the presence of inhibiting substances [24]. Additionally, validation of these tests is primarily analytical and not against clinically obtained specimens. Bacterial culture has traditionally been considered the ‘gold standard’ for diagnosis; however, its sensitivity, even in excellent laboratories, seldom exceeds 90% and is typically between 75% and 85%. The culture is techni- cally difficult to implement and is only available in a few laboratories worldwide [25]. Even though MIF is still actually considered as the ‘serological gold standard’ technique for the detection of species-specific antibodies, there is a large discrepancy between MIF testing for C. pneumonia and detection of these organisms by culture or PCR. The MIF test is reli- able for detection of a prior exposure to Chlamydiae by the presence of immunoglobulin G (IgG) antibodies and is relatively sensitive for the detection of IgM. IgM is an unreliable marker of acute infection in adolescents and adults since it is often not present, presumably because of previous infection by a chlamydial species [24]. Addi- tionally, MIF is quite a laborious and subjective