The slow, gradual shift from dopamine to norepinephrine as the vasopressor of choice in septic shock has another piece of ammunition - this time a meta-analysis of the observational and randomized trials.
They perform two separate analyses - an analysis of five observational trials and an analysis of six randomized trials. They find heterogeneity and no difference in the observational analysis - and then drop the observational trial responsible for the heterogeneity, and find an RR for mortality of 1.23 favoring norepinephrine. Then, with the randomized trials, they find an RR for mortality of 1.10 favoring norepinephrine. The RR for arrhythmias associated with dopamine use was 2.34 in their pooled analysis.
Of the RCTs, most of the patients came from one trial with 1044 patients and includes four trials with fewer than 50, so it's not exactly as though this analysis adds a lot of statistical power - but it's enough to reinforce the trends from each trial.
It is reasonable to suggest that norepinephrine is superior to dopamine - but I would also suggest the magnitude of that difference, given the data we have so far, has only been shown to be small.
"Dopamine versus norepinephrine in the treatment of septic shock: A meta-analysis"
http://www.ncbi.nlm.nih.gov/pubmed/22036860
