[Effects of recruitment maneuvers with low tidal volume ventilation in patients with acute respiratory distress syndrome].

OBJECTIVE: To assess the effects of recruitment maneuvers (RMs) with low tidal volume (V(T)) ventilation on gas oxygenation and reduction of ventilation-associated lung injury (VALI) in patients suffering from acute respiratory distress syndrome (ARDS), to assess the effects of RMs on blood pressure, heart rate and occurrence of barotrauma.

METHODS: Patients in intensive care unit (ICU) of Beijing Fuxing Hospital were randomized into two groups: low V(T)+RM group and low V(T) without RM group (non-RM group). Twenty-eight patients with early ARDS admitted from January 2003 to March 2004 were enrolled in the study. All patients received protective ventilation: V(T) was set at 6 ml/kg with plateau pressure limited at 30 cm H(2)O (1 cm H(2)O=0.098 kPa) or lower, positive end-expiratory pressure (PEEP) and fraction of inspired oxygen (FiO(2)) were set to obtain an partial pressure of arterial oxygen (PaO(2)) between 60 to 80 mm Hg (1 mm Hg=0.133 kPa). RMs were conducted by regulating FiO(2) to 1.00, applying 40 cm H(2)O of continuous positive airway pressure (CPAP) for 40 seconds, and then resumed the previous ventilator settings (mode, PEEP, and FiO(2)). This modality was repeated once every 8 hours for a total of 5 days. Measurements of PaO(2)/FiO(2), serum interleukin-6 (IL-6) concentration, respiratory and radiographic data, and ventilatory parameters were obtained at baseline and for the first 5 days. Mean arterial pressure and heart rate and pulse oxygen saturation (SpO(2)) were measured before and after the RM. The primary outcome was mortality at 28 days.

RESULTS: (1) After RM, PaO(2)/FiO(2) and PaO(2) in RM group and non-RM group increased, but the values were higher in RM group, and the difference between two groups was significant (all P<0.05). (2) IL-6 concentrations decreased in both groups but lower in RM group with significant difference (P<0.05). (3) Barotrauma did not occur in both groups. (4) No significant changes in blood pressure and heart rate were found during RMs. HR and MAP remained unchanged after RM.

CONCLUSION: RM could recruit the collapsed alveoli in ARDS. It could significantly improve oxygenation and decrease VALI. A superimposed RM is safe, and repeated RM could also decrease barotrauma.