[Clinical effects of low-stretch ventilation on acute respiratory distress syndrome].

OBJECTIVE: To investigate the effectiveness of low-stretch as compared with low-tidal-volume strategy in the treatment of acute respiratory distress syndrome (ARDS).

METHODS: Eighty-five cases of ARDS patients were randomly divided into low-stretch group (42 cases) and low-tidal-volume group (43 cases). The former group of patient received pressure assist control mode with not higher than 35 cm H(2)O (1 cm H(2)O=0.098 kPa) of peak pressure or pressure support mode ventilation with not higher than 30 cm H(2)O of Pplateau, while in low-tidal-volume group tidal volume of no more than 6 ml/kg of predicted body weight was given. The mortality rate within 28 days, the incidence of hypercapnia, the duration of using sedatives and neuromuscular blockade agents, the time of ventilation and the length of intensive care unit (ICU) stay were compared between two groups. According to the monitored expiratory tidal volume (V(T)e), the low-stretch group was divided into low-tidal-volume subgroup (V(T)e < or =6 ml/kg, 11 cases) and non-low-tidal-volume subgroup (V(T)e >6 ml/kg, 31 cases). The mortality within 28 days and the incidence of hypercapnia were compared between two subgroups.

RESULTS: There was no significant difference in the 28-day mortality rate between two groups (34.0% vs. 37.0%, P>0.05), but patients of low-stretch group had lower incidence of hypercapnia than low-tidal-volume group (10.6% vs. 40.7%, P<0.05), and also the duration of using sedatives [(4.5+/-1.2) days vs. (8.7+/-2.3) days] and neuromuscular blockade agents [(8.4+/-2.1) days vs. (10.7+/-1.2) days], and the length of ventilation and ICU stay [(10.2+/-2.2) days vs. (13.7+/-3.1) days, all P<0.05] were less. Low tidal volume occurred in 26.2% of low-stretch group, and the low-tidal-volume subgroup had higher 28-day mortality rate (40.8%) and incidence of hypercapnia (65.7%) than non-low-tidal-volume subgroup (13.2% and 8.6%, both P<0.05).

CONCLUSION: Compared with low-tidal-volume strategy, low-stretch strategy can reduce the incidence of hypercapnia, the length of ventilation and ICU stay for ARDS patients, but have similar mortality rate. When low-stretch strategy is exercised, an inappropriate low tidal volume may be associated with poor outcome of ARDS.