The comprehensive literature search yielded 60 references, of which 46 articles were excluded during the first screening, which was based on abstracts or titles, leaving 14 articles for full text review. During this review, 11 articles were excluded for the following reasons: letter to editor (n
5); non-randomized trial (n
3); review article (n
2); and case report (n
1). Finally, three articles (431 participants) were included in the final analysis [3
] (Figure ).
All three studies analyzed were randomized controlled trials and uses placebo in the control arm. All three studies used cisatracurium during 48 hours for myorelaxation, and two studies assessed neuromuscular blockade with the train-of-four [6
]. The mean follow-up for the assessment of gas exchange was 136.00
27.71 hours. Characteristics of the studies analyzed are show in Table and the study quality assessment is show in Table .
Characteristics of the studies included
Seventy out of 223 patients (31.4
%) assigned to neuromuscular blockade and 93 out of 208 patients (44.7
%) assigned as controls died during ICU stay (Risk ratio [RR], 0.71 [95
% CI, 0.55 – 0.90]; number needed to treat [NNT], 1 – 7). After analyzed 385 patients from two studies [3
], this finding was similar after 28
days of follow-up (RR, 0.69 [95
% CI, 0.51 – 0.92]; NNT, 1 – 8). Patients treated with NMBA needed less days of mechanical ventilation with a higher number of ventilator-free days at day 28 (p
0.0020). At the final of follow-up, patients treated with NMBA showed an increase in PaO2
0.004), at lower FiO2
0.002). The incidence of barotrauma was lower in patients under neuromuscular blockade (p
0.030) while the incidence of critical illness neuromyopathy was similar in both groups (p
0.540). (Table and Figure ).
Baseline characteristics and outcomes of the patients
Effect of neuromuscular blockade in patients with ARDS at the end of the follow-up period for each study.
levels, tidal volume, and plateau pressure were similar in both groups at the final follow-up (p
0.850, and p
0.250, respectively). There was a trend to the use of lower PEEP levels in patients under NMBA (p
0.060), and even with the same tidal volume, patients treated with NMBA had lower plateau pressure at final follow-up, although this not reached significance (p
0.250). However, when we assessed the changes of the variables during the follow-up (last value of the follow-up – baseline values) we founded a higher decrease in PEEP levels (− 2.20
1.90 vs. - 0.46
0.56, for NMBA and controls, respectively; p
0.050), and in plateau pressure (− 3.66
1.49 vs. - 0.70
0.60, for NMBA and controls, respectively; p
0.050). (Table ). One day after the final of infusion (72 hours) patients in the NMBA group presented a higher increase in PaO2
ratio and a higher decrease in the plateau pressure (Table and Figure ).
Difference of physiological variables one day after the final of the NMBA infusion (72 hours)
Changes in PaO2/ FiO2( circles ), plateau pressure ( triangles ) and PEEP (squares ) between patients under NMBA ( continuous line and closed symbols ) and controls ( dashed lines and open symbols ).
In Table , the GRADE evidence profile is provided. This profile evaluates the impact of NMBA in patients with ARDS.
GRADE evidence profile for impact of NMBA in acute ARDS from systematic review and meta-analysis of randomized controlled trials