[Therapy of acute respiratory distress syndrome : Survey of German ARDS centers and scientific evidence]

BACKGROUND

In addition to specific treatment of the underlying cause, the therapy of acute respiratory distress syndrome (ARDS) consists of lung protective ventilation and a range of adjuvant and supportive measures.

AIM

A survey was conducted to determine the current treatment strategies for ARDS in German ARDS centers.

MATERIAL AND METHODS

The 39 centers listed in the German ARDS network in 2011 were asked to complete a questionnaire collecting data on the clinic, epidemiology as well as diagnostic and therapeutic measures regarding ARDS treatment.

RESULTS

Of the centers 25 completed the questionnaire. In 2010 each of these centers treated an median of 31 (25-75 percentile range 20-59) patients. Diagnostic measures at admission were computed tomography of the thorax (60 % of the centers), whole body computed tomography (56 %), chest x-ray (52 %), abdominal computed tomography (32 %) and cranial computed tomography (24 %). Transesophageal echocardiography was performed in 64 %, pulmonary artery pressure was measured in 56 % and cerebral oximetry in 12 %. Sedation was regularly interrupted in 92 % of the centers and in 68 % this was attempted at least once a day. A median minimum tidal volume of 4 ml/kg (range 2-6) and a maximum tidal volume of 6 ml/kg (4-8) were used. Methods to determine the optimal positive end-expiratory pressure (PEEP) were the best PEEP method (60 %), ARDS network table (48 %), empirical (28 %), pressure volume curve (16 %), computed tomography (8 %), electrical impedance tomography (8 %) and others (8 %). Median minimum and maximum PEEPs were 10 cmH2O (range 5-15) and 21 cmH2O (15-25), respectively. Median plateau pressure was limited to 30 cmH2O (range 26-45). The respiratory rate was set below 20/min in 20 % and below 30/min in 44 %. Controlled ventilator modes were generally preferred with 80 % using biphasic positive airway pressure (BIPAP/BiLevel), 20 % pressure controlled ventilation (PCV) and 4 % airway pressure release ventilation (APRV). Assisted modes were only utilized by 8 % of the centers. Recruitment maneuvers were used by 28 %, particularly during the early phase of the ARDS. Muscle relaxants were administered by 32 % during the early phase of the ARDS. Complete prone positioning was used by 60 % of the centers, whereas 88 % utilized incomplete (135°) prone positioning. Continuous axial rotation was utilized by 16 %. Spontaneous breathing tests were used in 88 % of the centers with 60 % performing these at least once a day. Supportive therapies were frequently applied and mainly consisted of nitrous oxide (44 %), prostacycline (48 %) and corticosteroids (52 %). A restrictive fluid therapy was used in 48 % and a special nutrition regimen in 28 % of the centers. Of the participating centers 22 were able to offer extracorporeal membrane oxygenation (ECMO). In this case, respiratory therapy was modified by further reducing tidal volumes (91 %), inspiratory pressures (96 %) as well as using lower respiratory rates (≤ 8/min in 31 %). Only 9 % reduced PEEP during ECMO. Regular recruitment maneuvers were used by 14 %. Positioning maneuvers during ECMO were used by 82 %.

CONCLUSIONS

Lung protective ventilation with reduced tidal volumes as well as inspiratory pressures represents the current standard of care and was utilized in all network centers. Prone positioning was widely used. Promising adjuvant therapies such as the muscle relaxation during the early phase of the ARDS, fluid restriction and corticosteroids were used less frequently. During ECMO respirator therapy was generally continued with ultraprotective ventilator settings.

Effects of venovenous extracorporeal membrane oxygenation on cerebral oxygenation in hypercapnic ARDS

Extracorporeal membrane oxygenation (ECMO) is increasingly used in ARDS patients with hypoxemia and/or severe hypercapnia refractory to conventional treatment strategies. However, it is associated with severe intracranial complications, e.g. ischemic or hemorrhagic stroke. The arterial carbon dioxide partial pressure (PaCO2) is one of the main determinants influencing cerebral blood flow and oxygenation. Since CO2 removal is highly effective during ECMO, reduction of CO2 may lead to alterations in cerebral perfusion. We report on the variations of cerebral oxygenation during the initiation period of ECMO treatment in a patient with hypercapnic ARDS, which may partly explain the findings of ischemic and/or hemorrhagic complications in conjunction with ECMO.

[Successful resuscitation after cardiac arrest using a precordial thump.]

The case of 16-year-old, ASA I classified patient who suffered cardiac arrest during orthopedic surgery is reported. Return of spontaneous circulation was achieved with a precordial thump. The patient was discharged from hospital without any neurological deficits 10 days after the event.