April 24, 2014
High versus Low Blood-Pressure Target in Patients with Septic Shock.
What was the research question?
In patient with septic shock, does a higher mean arterial pressure improve mortality compared to a lower mean arterial pressure?
How did they do it?
Multicenter, open label, randomized trial in 29 centers in France
776 patients with septic shock were randomly assigned to undergo resuscitation with a mean arterial pressure target of either 80 to 85 mm Hg (high-target group) or 65 to 70 mm Hg (low-target group).
The primary end point was mortality at day 28.
What did they find?
28-day mortality was not significantly different between the high-target group compared to low-target group (36.6% vs. 34%; P=0.57).
No significant difference in mortality at 90 days with 43.8% compared to 42.3% respectively (P=0.74).
Serious adverse events did not differ significantly between the two groups (19.1% vs. 17.8%; P=0.64). However, new onset age fibrillation was higher in the high-target group compared to the low-target group (6.7% vs. 2.8%, P=0.02).
In patients with chronic hypertension (n=340), renal replacement therapy was required at lower frequency in the high-target group compared to low target group (31.7% vs. 42.2%, p=0.046, NNT 9.5), but no difference in mortality.
Are there any limitations?
The study is underpowered with a higher risk of type II error due to a lower mortality than predicted.
Slow recruitment process which may limit the external validity of the trial.
There is a compliance bias in favor of the null hypothesis as 16.5% of patients in the high-target group versus 10.3% (P=0.01) in the low-target failed to achieve the target bold pressure.
What does it mean?
No difference in 28- or 90-day mortality in patients with septic shock and a mean arterial pressure of 80-85 mm Hg compared to 65-70 mm Hg.
For the majority of septic shock patients, we target MAP of 65-70 mm Hg and may choose a higher target of 80-85 mm Hg in patients with history of chronic hypertension.