Shock 的治療目標 Early goal-directed therapy
Early goal-directed therapy: do we have a definitive answer?
by Daniel De Backer| Jean-Louis Vincent
Early goal-directed therapy (EGDT) for the treatment of septic shock was first proposed in 2001 by Rivers et al. [1]. These authors reported that patients with hypotension refractory to a fluid challenge of 20–30 ml/kg of crystalloids over 30 min or with plasma lactate levels of at least 4 mEq/l and who were treated to restore and maintain a central venous oxygen saturation (ScvO2) of greater than 70 % had lower 28-day mortality rates than control patients (33 vs 49 %). That publication generated considerable enthusiasm but also much debate. The resuscitation protocol was incorporated into the Surviving Sepsis Campaign (SSC) guidelines [2] and several uncontrolled studies reported similar improvements in outcome [3–5]. However, concerns were raised about the single-center nature of the trial, the limited sample size (263 patients), the multiple interventions proposed in the EGDT package making it difficult to differentiate which was most effective, and the potential influence of confounding factors including the increased presence of doctors at the bedside of patients randomized to the intervention.
Three large-scale multicenter studies published in 2014 and 2015 [6–8] were unable to replicate the results of the Rivers study, but is there a plausible explanation for this? Among the important differences between the trials, the mortality rate in the control groups in the recent trials was markedly lower than that in the Rivers study (Table 1). In addition, ScvO2 values in the study groups were markedly reduced (to an average of 49 %) in the Rivers trial but were already within the greater than 70 % target zone in the three other trials. One explanation may be that Rivers et al. treated a special patient population with severe comorbidities and/or who presented quite late to the emergency department. Another possible explanation is that there has been a marked improvement in prehospital and initial care of patients with septic shock, maybe as a direct result of the Rivers trial and the SSC guidelines. However, adequacy of antibiotic treatment and amounts of fluid administered prior to randomization do not seem to account for these differences (Table 1).
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This patient selection issue does not challenge the internal validity of these recent trials, but clearly raises questions about their external validity. These trials have indicated that patients with low severity septic shock who rapidly respond to therapy do not benefit from routine EGDT. However, the results of the Rivers trial have not been invalidated as patients with high disease severity and low ScvO2 were not included in these recent trials. EGDT may still be beneficial in the most severely ill patients, especially when less experienced staff who may appreciate using simple protocols are in charge.
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