a 5-year - old girl is admitted to the paediatric intensive care unit with meningococcal sepsis . you are trying to decide which type of fluid to choose ( crystalloids or natural colloids [ albumin ] ) . puran khandelwal and desmond bohn meningococcal sepsis is a fulminant form of gram - negative sepsis associated with profound shock . the release of endotoxins ( lipopolysaccharides ) from the bacterial cell wall initiates a cascade of events resulting in the release of cytokines ( il-1 , il-6 , tumour necrosis factor alpha ) , which in turn causes endothelial cell injury with capillary leak and loss of vasomotor tone . plasma proteins , including albumin , and water from the intravascular compartment leak into the interstitium , resulting in hypovolaemia and hypotension . fleck and colleagues   showed that there is an increase of 300% in the albumin escape rate from the vascular to the interstitial space , associated with hypoalbuminaemia , in septic patients . holland and colleagues found albumin fragments of approximately 45 kda , 25 kda , and < 20 kda in the urine of children with meningococcal sepsis and associated purpura . they suggested that exogenous or endogenous proteases , or both , may be released in severe meningococcal sepsis and , in association with an inadequate antiprotease response , result in albumin degradation . this may be a contributory factor to the rapid shock , hypocalcaemia , and rash seen in meningococcal sepsis . early fluid resuscitation in paediatric septic shock improves outcome , but there is ongoing controversy over the type of fluid to be used . two published meta - analyses , by the cochrane group , of randomised trials that compared crystalloids with colloids or crystalloids with albumin attracted considerable attention . they concluded that the use of both colloids was associated with increased mortality in critically ill patients . there were only six paediatric studies analysed , five of which were in neonates , one was in burns in children . none were in patients with sepsis . despite the concerns raised by the publication of these papers , early aggressive fluid resuscitation with albumin , specialist advice and transfer to a paediatric intensive care unit for patients with meningococcal sepsis in the uk has reduced mortality from 50% in severely ill patients to less than 5% . understanding of the distribution of colloids and crystalloids in the different fluid compartments is fundamental to fluid resuscitation . ernest and colleagues studied the distribution of normal saline and 5% albumin in septic patients . normal saline increases the extracellular fluid compartment 1:1 ratio with only 20% remaining with the intravascular space , whereas 5% albumin increases extracellular fluid more than twice and is distributed equally intravascularly and interstitially . volume for volume , two to three times as much crystalloid needs to be used as colloid for the same haemodynamic effect . a recent randomised , controlled trial showed greater improvements in haematocrit , pulse pressure , and cardiac index among children with dengue shock syndrome who received colloid compared with a crystalloid . the use of a large volume of and rapid infusion of normal saline will produce hyperchloraemic acidosis and has the potential to worsen acidosis . joseph a carcillo and neal j thomas it is well accepted that fluid resuscitation in paediatric septic shock is critical . carcillo and colleagues   reported a decade ago that paediatric patients in septic shock had reduced mortality with rapid fluid administration , initially with crystalloids but with one - third of the total fluid given as colloid . . however , the debate continues concerning the optimum initial fluid to utilise . after reviewing the available literature concerning primary fluid options , we present facts that refute the statement ' colloids have advantages over crystalloids in paediatric sepsis ' . to defend the statement that colloids are superior , one must prove their benefit in the clinical setting described : paediatric septic shock . because of the lack of literature available in this patient subset , a broad base of literature review must cover adult patients in a wide variety of clinical situations , including sepsis . choi and colleagues   reviewed 17 studies encompassing 814 patients that compared isotonic crystalloids with colloids for fluid resuscitation . the authors concluded that there was no advantage in terms of outcome or length of stay with colloids . in an attempt to determine whether a larger amount of colloid or crystalloid remained in the intravascular compartment , ernest and colleagues randomised septic adult patients to receive either normal saline or 5% albumin . they concluded that there was no advantage in the haemodynamics of patients who received albumin . to further this argument , we present the case that colloids may actually be harmful to patients . castro and colleagues   raised concerns about the adverse rheologic effects with colloid infusions , citing that hydroxyethyl starch increases blood viscosity and has the potential to impair microvascular flow during sepsis . additionally , a recent meta - analysis of 30 randomised , controlled trials including 1149 patients concluded that , in addition to no evidence suggesting that mortality was improved with albumin administration , there was a strong suggestion that albumin may actually increase mortality . another meta - analysis   revealed an increased absolute risk of mortality of 4% in patients resuscitated with colloids . these studies have prompted the food and drug administration to issue a warning : " ... the fda urges treating physicians to exercise discretion in use of albumin ... " . in this age of cost containment , crystalloid solutions can generally be acquired at $ 1/500 ml , in comparison with hydroxyethyl starch ( $ 45/500 ml ) or 5% albumin ( $ 76/100 ml ) . it is easy to see that the utilisation of crystalloid solutions for initial resuscitative measures can result in significant cost savings . based on the lack of evidence documenting improved outcome , potential deleterious effects , and substantial economic strain on the health care system , we agree with the recent review by alderson and colleagues . they concluded " it is hard to see how their ( colloids ) continued use in these patient types ( critically ill ) can be justified outside the context of randomized controlled trials " . puran khandelwal and desmond bohn carcillo and thomas noted that colloid was used when crystalloids failed to improve perfusion or blood pressure , or for correcting coagulation . ernest and colleagues   used 5% albumin or normal saline to achieve a similar haemodynamic target ( pulmonary artery occlusion pressure= 15 mmhg ) , and found albumin more efficient ( 122% versus 21% ) . meta - analyses are limited in their ability to examine the effects of crystalloids or colloids for fluid resuscitation . the heterogeneity in the study population , selection criteria and different outcome measures included in the meta - analysis can influence the result . it is interesting to note , however , that wilkes and navickis   have shown in their meta - analysis that albumin has no effect on mortality . an appropriately powered and clinically relevant randomised , controlled clinical trial is needed to resolve these issues . joseph a carcillo and neal j thomas khandelwal and bohn present some excellent arguments to support their view that colloids should be administered as resuscitative fluids in this child . however , the prime question concerning whether colloids will improve outcome in this type of patient remains unanswered . we agree that the literature is limited with regards to paediatric septic shock , but this should not cause us to ignore the data that has been generated by our adult colleagues and to recommend a therapy that may in fact be harmful . instead , it should invite us to answer the question in our distinct population of children with septic shock by a well - planned , randomised , controlled trial .
despite decades of resuscitating patients with intravenous fluids in intensive care units , it is somewhat surprising that very little consensus exists regarding the type of fluid physicians should choose . 
 factors that influence decisions are often local culture or politics , hospital administrators , history ( i.e. ' i 've always done it this way ' ) and budgets , as opposed to strong evidence . in the present issue of critical care 
 we are presented with compelling arguments for and against the administration of colloids ( as opposed to crystalloids ) in paediatric sepsis . 
 one point that appears to be clear is that the ideal choice of intravenous fluid goes beyond the simple haemodynamic effect . 
 as such , in the future , clinicians will need to consider other factors when making their decision . 
 in addition , large - scale quality randomised studies are desperately needed to guide clinicians .