The optimal strategy of fluid resuscitation in the early hours of severe sepsis and septic shock is controversial, with both an aggressive and conservative approach being recommended.
We used the 2013 Premier Hospital Discharge database to analyse the administration of fluids on the first ICU day, in 23,513 patients with severe sepsis and septic shock, who were admitted to an ICU from the emergency department. Day 1 fluid was grouped into categories 1 L wide, starting with 1–1.99 L up to >9 L, to examine the effect of day 1 fluids on patient mortality. We built binary response models for hospital mortality and the propensity for receiving more than 5 L of fluids on day 1, using patient age and acute conditions present on admission. Patients were grouped by the requirement for mechanical ventilation and the presence or absence of shock. We assessed trends in the difference between actual and expected mortality, in the low fluid range (1–5 L day 1 fluids) and the high fluid range (5 to >9 L day 1 fluids) categories, using weighted linear regression controlling for the effects of sample size and variation within the day 1 fluid category.
Day 1 fluid administration averaged 4.4 L being lowest in the group with no mechanical ventilation and no shock (3.6 L) and highest (5.4 L) in the group receiving mechanical ventilation and in shock. The administration of day 1 fluids was remarkably consistent on the basis of hospital size, teaching status, rural/urban location, and region of the country. The hospital mortality in the entire cohort was 25.8%, with a mean ICU and hospital length of stay of 5.1 and 9.1 days, respectively. In the entire cohort, low volume resuscitation (1–4.99 L) was associated with a small but significant reduction in mortality, of -0.7% per litre (95% CI -1.0%, -0.4%; p = 0.02). However, in patients receiving high volume resuscitation (5 to >9 L), the mortality increased by 2.3% (95% CI 2.0, 2.5%; p = 0.0003) for each additional litre above 5 L. Total hospital cost increased by $999 for each litre of fluid above 5 L (adjusted R2 = 92.7%, p = 0.005).
The mean amount of fluid administered to patients with severe sepsis and septic shock in the USA during the first ICU day is less than that recommended by the Surviving Sepsis Campaign guidelines. The administration of more than 5 L of fluid during the first ICU day is associated with a significantly increased risk of death and significantly higher hospital costs.
This is the largest observational study published to date examining the relationship between Day 1 fluid administration in patients with sepsis and mortality. The strength of the study lies in the fact that it is representative of real-life practice in the USA. Secondly, complex statistical models were developed which allowed for the comparison between the actual mortality and predicted mortality for each patient and for the deciles of Day 1 fluid administration (see figure below).
This study (ONCE again) has demonstrated that a liberal initial approach to fluid administration is associated with an increase in death. Administration of greater than 5L fluid on Day 1 increased the risk of death. Equally important, lower volumes of fluid administration were associated with a small but statistically significant reduction in mortality (see Figure below). These findings STRONGLY contradict the Surviving Sepsis Campaign Guidelines which recommend “aggressive fluid resuscitation during the first 24 h”.
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