Conservative fluid management: Turn off the tap after use?
Fluid therapy is one of the oldest and most commonly performed interventions in critical care medicine. In the recently published updated guidelines by the Surviving Sepsis Campaign, fluid administration is the mainstay of initial resuscitation of septic patients and it should be performed early . However, a growing body of evidence highlights the potential detrimental effects of a large volume of fluids after initial resuscitation. Indeed, fluid overload brings a number of negative effects such as pulmonary oedema with impaired gas exchange, tissue interstitial edema with impaired oxygen diffusion and haemodilution. The term deresuscitation describes the attempt to bring the patient to the phase of normovolemia after the resuscitation and stabilisation phases . This goal may be reached with restrictive fluid administration protocols or active measures of fluid removal.
Silversides and colleagues performed a systematic review and meta-analysis of studies comparing two different fluid regimens in adults and children with sepsis or acute respiratory distress syndrome (ARDS) . Authors included both observational and randomised controlled studies (RCTs), but they performed the quantitative analysis with RCTs only. The meta-analysis of 11 RCTs led to a not significant effect on survival of the conservative/deresuscitation fluid strategy compared to the liberal strategy or usual care. However, authors reported a significant increase in ventilator-free days and reduced length of ICU-stay without evidence of an increase in acute kidney injury, use of renal replacement therapy and cognitive dysfunction . Quality of available evidence was low or very low. The results were mostly driven by the FACTT trial, a large randomised trial, which, to date, represented the single most powered available study investigating two fluid strategies in patients with lung injury .
A previously published systematic review and meta-analysis aiming to assess the association of fluid overload with outcome of critically ill patients, reported a survival benefit in patients treated with interventions attempting to reduce fluid overload after the resuscitation phase. Notably, this review included also observational studies in which more severely ill patients may have received more fluids or who clinicians would not deresuscitate . The attempt to include a wide range of critically ill patients was paid with a high clinical heterogeneity, which was also driven by the wide range of definition of restrictive vs liberal fluid strategies, adopted interventions and outcomes of the included studies. However, well performed systematic reviews and meta-analysis are hypothesis generating and assess the quality of available evidence. In this sense, the article by Silversides and colleagues highlights the lack of high-quality evidence supporting clinicians’ decisions on fluid management and advocates a large multicentre trial providing more solid answers.
Article review submitted by EJRC member Vincenzo Russotto, Department of Biopathology and Medical Biotechnologies (DIBIMED), Section of Anaesthesia, Analgesia, Intensive Care and Emergency, University Hospital Paolo Giaccone, University of Palermo, Italy.
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