Improved gas exchange has been observed during spontaneous breathing with airway pressure release ventilation (APRV) as compared with controlled mechanical ventilation. This study was designed to determine whether use of APRV with spontaneous breathing as a primary ventilatory support modality better prevents deterioration of cardiopulmonary function than does initial controlled mechanical ventilation in patients at risk for acute respiratory distress syndrome (ARDS). Thirty patients with multiple trauma were randomly assigned to either breathe spontaneously with APRV (APRV Group) (n = 15) or to receive pressure-controlled, time-cycled mechanical ventilation (PCV) for 72 h followed by weaning with APRV (PCV Group) (n = 15). Patients maintained spontaneous breathing during APRV with continuous infusion of sufentanil and midazolam (Ramsay sedation score [RSS] of 3). Absence of spontaneous breathing (PCV Group) was induced with sufentanil and midazolam (RSS of 5) and neuromuscular blockade. Primary use of APRV was associated with increases (p < 0.05) in respiratory system compliance (CRS), arterial oxygen tension (PaO2), cardiac index (CI), and oxygen delivery (DO2), and with reductions (p < 0.05) in venous admixture (QVA/QT), and oxygen extraction. In contrast, patients who received 72 h of PCV had lower CRS, PaO2, CI, DO2, and Q VA/Q T values (p < 0.05) and required higher doses of sufentanil (p < 0.05), midazolam (p < 0.05), noradrenalin (p < 0.05), and dobutamine (p < 0.05). CRS, PaO2), CI and DO2 were lowest (p < 0.05) and Q VA/Q T was highest (p < 0.05) during PCV. Primary use of APRV was consistently associated with a shorter duration of ventilatory support (APRV Group: 15 +/- 2 d [mean +/- SEM]; PCV Group: 21 +/- 2 d) (p < 0.05) and length of intensive care unit (ICU) stay (APRV Group: 23 +/- 2 d; PCV Group: 30 +/- 2 d) (p < 0.05). These findings indicate that maintaining spontaneous breathing during APRV requires less sedation and improves cardiopulmonary function, presumably by recruiting nonventilated lung units, requiring a shorter duration of ventilatory support and ICU stay.

ObjectiveWe report on the effect of hemoadsorption therapy to reduce cytokines in septic patients with respiratory failure.MethodsThis was a randomized, controlled, open-label, multicenter trial. Mechanically ventilated patients with severe sepsis or septic shock and acute lung injury or acute respiratory distress syndrome were eligible for study inclusion. Patients were randomly assigned to either therapy with CytoSorb hemoperfusion for 6 hours per day for up to 7 consecutive days (treatment), or no hemoperfusion (control). Primary outcome was change in normalized IL-6-serum concentrations during study day 1 and 7.Results97 of the 100 randomized patients were analyzed. We were not able to detect differences in systemic plasma IL-6 levels between the two groups (n = 75; p = 0.15). Significant IL-6 elimination, averaging between 5 and 18% per blood pass throughout the entire treatment period was recorded. In the unadjusted analysis, 60-day-mortality was significantly higher in the treatment group (44.7%) compared to the control group (26.0%; p = 0.039). The proportion of patients receiving renal replacement therapy at the time of enrollment was higher in the treatment group (31.9%) when compared to the control group (16.3%). After adjustment for patient morbidity and baseline imbalances, no association of hemoperfusion with mortality was found (p = 0.19).ConclusionsIn this patient population with predominantly septic shock and multiple organ failure, hemoadsorption removed IL-6 but this did not lead to lower plasma IL-6-levels. We did not detect statistically significant differences in the secondary outcomes multiple organ dysfunction score, ventilation time and time course of oxygenation.

Ventilation-perfusion (V A/Q) distributions were evaluated in 24 patients with acute respiratory distress syndrome (ARDS), during airway pressure release ventilation (APRV) with and without spontaneous breathing, or during pressure support ventilation (PSV). Whereas PSV provides mechanical assistance of each inspiration, APRV allows unrestricted spontaneous breathing throughout the mechanical ventilation. Patients were randomly assigned to receive APRV and PSV with equal airway pressure limits (Paw) (n = 12) or minute ventilation (V E) (n = 12). In both groups spontaneous breathing during APRV was associated with increases (p < 0.05) in right ventricular end-diastolic volume, stroke volume, cardiac index (CI), PaO2, oxygen delivery, and mixed venous oxygen tension (PvO2) and with reductions (p < 0.05) in pulmonary vascular resistance and oxygen extraction. PSV did not consistently improve CI and PaO2 when compared with APRV without spontaneous breathing. Improved V A/Q matching during spontaneous breathing with APRV was evidenced by decreases in intrapulmonary shunt (equal Paw: 33 +/- 4 to 24 +/- 4%; equal V E: 32 +/- 4 to 25 +/- 2%) (p < 0.05), dead space (equal Paw: 44 +/- 9 to 38 +/- 6%; equal V E: 44 +/- 9 to 38 +/- 6%) (p < 0.05), and the dispersions of ventilation (equal Paw: 0.96 +/- 0.23 to 0.78 +/- 0.22; equal V E: 0.92 +/- 0.23 to 0.79 +/- 0.22) (p < 0.05), and pulmonary blood flow distribution (equal Paw: 0.89 +/- 0.12 to 0.72 +/- 0.10; equal V E: 0.94 +/- 0.19 to 0.78 +/- 0.22) (p < 0.05). PSV did not improve V A/Q distributions when compared with APRV without spontaneous breathing. These findings indicate that uncoupling of spontaneous and mechanical ventilation during APRV improves V A/Q matching in ARDS presumably by recruiting nonventilated lung units. Apparently, mechanical assistance of each inspiration during PSV is not sufficient to counteract the V A/Q maldistribution caused by alveolar collapse in patients with ARDS.