Reperfusion Injury After Hemorrhage: A Collective Review

G D. Rushing, MD; L D. Britt, MD, MPH

Disclosures

Annals of Surgery. 2008;247(6):929-937. 

In This Article

Colloids Versus Crystalloids

The type of fluids used for resuscitative efforts is still a topic of much debate. Although colloids are effective in expanding the circulation, there is no evidence that this improves outcomes in critically ill patients.[28] The U.S. Hospital Consortium Guidelines recommend that colloids be used in hemorrhagic shock before the availability of blood products, and in nonhemorrhagic shock after an initial crystalloid infusion. A 1995 survey of U.S. academic health centers, however, found that the use of colloids far exceeded even the Hospital Consortium recommendations.[29] Volume replacement with colloids is considerably more expensive than with crystalloids. Clinical studies demonstrate that colloids and crystalloids have different effects on a range of important physiological parameters. Because of these differences, all-cause mortality is arguably the most clinically relevant outcome measure in randomized trials comparing the 2 fluid types. Previous meta-analyses of mortality in randomized trials comparing colloids and crystalloids do not satisfy criteria laid out for scientific overviews, and they predate most of the trials conducted using synthetic colloids or hypertonic crystalloid solutions.[30,31] A recent prospective study, the Saline versus Albumin Fluid Evaluation trial, attempted to determine whether the use of albumin for fluid resuscitation had a detrimental effect on mortality in critically ill patients.[32] There was no significant difference between albumin or saline in the number of days spent in the intensive care unit, days spent in the hospital, days of mechanical ventilation, days of renal replacement therapy, or all-cause 30-day mortality within this study. The most recent meta-analysis is a Cochrane review analyzing the use of colloids and crystalloids in resuscitation.[33] This review is a consortium of critically ill patients, however, not all subjects are purely victims of hemorrhagic shock. Nevertheless, these are the best data to date. This meta-analysis conveys several important implications. First, there is still no evidence that colloids are superior to crystalloids for intravascular volume resuscitation in critically ill patients. Importantly, the Saline versus Albumin Fluid Evaluation trial provides no evidence that the use of albumin is clinically advantageous. Second, albumin carries, at least, a theoretical risk of transmission of infections. Third, the economic cost of colloids for resuscitation is considerable and, therefore, its ongoing use in this context is unjustified.

In groundbreaking work by Rhee and colleagues, hypertonic saline has been advocated as a viable option for resuscitative fluid for hemorrhagic shock.[34] In this study, looking at differing resuscitative fluids and neutrophil function, oxidative burst was suppressed when exposed to hypertonic saline. Changing the isomer of lactate in Lactated Ringer's solution from racemic (mixture) to a specific (l) isomer has a similar effect on neutrophil activity. Using only (l) isomer lactated Ringer solution in resuscitation of rodents, leukocyte genes known to be involved in inflammation, cell migration, and apoptosis were down-regulated. Immunomodulation of type-specific fluids is now a burgeoning topic in trauma resuscitation research.

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