The effects of commonly used resuscitation fluids on whole blood coagulation

Objectives

Evidence on the effect of crystalloid and colloid resuscitation fluids on coagulation is confusing, with contradictory results from previous studies. This study was performed to test the effect on whole blood coagulation of a range of resuscitation fluids in vitro using a single method at a single dilution.

Methods

Seven resuscitation fluids were tested in vitro at a dilution of 40%. Whole blood coagulation was measured using a Sonoclot analyser.

Results

A crystalloid/colloid split of effect on coagulation in vitro was not seen. The time to clot formation with Gelofusine, dextran and hydroxyethyl starch was a greatly increased, whereas saline and Haemaccel had little effect, or were slightly procoagulant.

Conclusions

Some resuscitation fluids have a profound effect on coagulation. The confusion in the literature may result from the effect on coagulation being both fluid and dilution dependent, with no simple crystalloid/colloid split.     

The fluid management of adults with severe malaria

Fluid resuscitation has long been considered a key intervention in the treatment of adults with severe falciparum malaria. Profound hypovolemia is common in these patients and has the potential to exacerbate the acidosis and acute kidney injury that are independent predictors of death. However, new microvascular imaging techniques have shown that disease severity correlates more strongly with obstruction of the microcirculation by parasitized erythrocytes - a process termed sequestration. Fluid loading has little effect on sequestration and increases the risk of complications, particularly pulmonary edema, a condition that can develop suddenly and unpredictably and that is frequently fatal in this population. Accordingly, even if a patient is clinically hypovolemic, if there is an adequate blood pressure and urine output, there may be little advantage in infusing intravenous fluid beyond a maintenance rate of 1 to 2 mL/kg per hour. The optimal agent for fluid resuscitation remains uncertain; significant anemia requires blood transfusion, but colloid solutions may be associated with harm and should be avoided. The preferred crystalloid is unclear, although the use of balanced solutions requires investigation. There are fewer data to guide the fluid management of severe vivax and knowlesi malaria, although a similar conservative strategy would appear prudent.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0642-6) contains supplementary material, which is available to authorized users.     

Fluid resuscitation in diabetic emergencies — a reappraisal

The first objective in diabetic ketoacidosis is to restore the circulating volume and improve tissue perfusion. In any form of hypovolaemic shock the most efficient way of restoring circulating volume is to be use colloid solutions rather than crystalloids. At least three times the amount of crystalloid must be used to achieve the same effect. The historical reason for using isotonic saline in diabetic ketoacidosis is related not to its similarity to the fluid lost, but to its supposed efficiency in correcting the circulating volume. Excess crystalloid expands the interstitial space which results in pulmonary oedema, peripheral oedema and possibly cerebral oedema. Although currently difficult to define precisely in their more subtle forms, they all produce adverse pathophysiological effects. The fluid loss in diabetic ketoacidosis is equivalent to "half-normal" saline, a relatively hypotonic solution. As well as causing extensive oedema, resuscitation with isotonic saline can increase serum sodium and osmolarity while not providing free water to replace the intracellular losses.     

Balanced vs unbalanced crystalloid resuscitation in a near-fatal model of hemorrhagic shock and the effects on renal oxygenation, oxidative stress, and inflammation

Background

The aim of the present study was to test the hypothesis that balanced crystalloid resuscitation would be better for the kidney than unbalanced crystalloid resuscitation in a rat hemorrhagic shock model.

Methods

Male Wistar rats were randomly assigned to four groups (n = 6/group): (1) time control; (2) hemorrhagic shock control; (3) hemorrhagic shock followed by unbalanced crystalloid resuscitation (0.9% NaCl); and (4) hemorrhagic shock followed by acetate and gluconate-balanced crystalloid resuscitation (Plasma Lyte). We tested the solutions for their effects on renal hemodynamics and microvascular oxygenation, strong-ion difference, systemic and renal markers of inflammation and oxidative stress including glycocalyx degradation as well as their effects on renal function.

Results

The main findings of our study were that: (1) both the balanced and unbalanced crystalloid solutions successfully restored the blood pressure, but renal blood flow was only recovered by the balanced solution although this did not lead to improved renal microvascular oxygenation; (2) while unbalanced crystalloid resuscitation induced hyperchloremia and worsened metabolic acidosis in hemorrhaged rats, balanced crystalloid resuscitation prevented hyperchloremia, restored the acid–base balance, and preserved the anion gap and strong ion difference in these animals; (3) in addition balanced crystalloid resuscitation significantly improved renal oxygen consumption (increased VO₂, decreased EFNa₊${\text{EF}}_{{\text{Na}}^{+}}$); and (4) however neither balanced nor unbalanced crystalloid resuscitation could normalize systemic inflammation or oxidative stress. Functional immunohistochemistry biomarkers showed improvement in L-FABP in favor of balanced solutions in comparison to the hemorrhagic group although no such benefit was seen for renal tubular injury (measured by NGAL) by giving either unbalanced or balanced solutions.

Conclusions

Although balanced crystalloid resuscitation seems superior to balanced crystalloid resuscitation in protecting the kidney after hemorrhagic shock and is certainly better than not applying fluid resuscitation, these solutions were not able to correct systemic inflammation or oxidative stress associated with hemorrhagic shock.     

The role of colloids in resuscitation

Colloids have been used for many years in resuscitation yet few studies have thoroughly examined their usefulness. Colloids and a combination of crystalloids and colloids continue to be used without any real scientific basis. Scrutiny of review articles, experimental studies, and clinical investigations reveals conflicting and confusing data. There are too many variables to accurately interpret findings, cross species problems with animal studies, different fluids used making comparisons difficult if not impossible, and confounding variables that include:

• 1 Health status of the patients
• 2 Severity/type of injury
• 3 Complications (especially sepsis)
• 4 Varying grades of shock
• 5 Variable time scale of administration of fluids
• 6 Variable volumes administered
• 7 Differing methods of determining fluid volume depletion
• 8 Inconsistent monitoring
• 9 Differing endpoints
• 10 Different techniques to measure endpoints
• 11 Comparison of delayed treatment of traumatic shock with blood loss occurring during surgery of questionable validity.

One of the areas that has been studied reasonably well is the allergic effects associated with colloid use and more recently the adverse effects associated with the use of dextrose solutions in patients with head injuries. The continued effort to develop satisfactory resuscitation solutions including the recent development of hypertonic saline solutions (usually in combination with a colloid) highlights the uncertainty that exists in relation to the true role of the colloid and crystalloid agents available. Recent studies question the use of fluids to resuscitate patients with penetrating torso injuries. The aim of this paper is to review what is known about the use of colloids and crystalloids in resuscitation and to recommend guidelines as to which fluid should be used in differing clinical situations.     

Review of a fluid resuscitation protocol: "fluid creep" is not due to nursing error

Recent reviews of burn resuscitation have included the suggestion that "fluid creep" may be influenced by practitioner error. Our center uses a nursing-driven resuscitation protocol that permits titration of fluid based on hourly urine output, including the addition of colloid when patients fail to respond appropriately. The purpose of this study was to examine protocol compliance. We reviewed 140 patients (26 children) with burns of ≥20% TBSA who received protocol-directed resuscitation from 2005 to 2010. We compared each patient's actual hourly fluid infusion with that predicted by the protocol. Sixty-seven patients (48%) completed resuscitation using crystalloid alone, whereas 73 patients required colloid supplementation. Groups did not differ in age, gender, weight, or time from injury to admission. Patients requiring colloid had larger median total burns (33.0 vs 23.5% TBSA) and full-thickness burns (15.5 vs 4.5% TBSA) and more inhalation injuries (60.3 vs 28.4%; P < .001) than those who resuscitated with crystalloid alone. Because we included basic maintenance fluids in their regimen, patients had median predicted requirements of 5.4 ml/kg/%TBSA. Crystalloid-only patients required fluid volumes close to Parkland predictions (4.7 ml/kg/%TBSA), whereas patients who received colloid required more fluid than the predicted volume (7.5 ml/kg/%TBSA). However, the hourly difference between the predicted and received fluids was a median of only 1.0% (interquartile range: -6.1 to 11.1%) and did not differ between groups. Pediatric patients had greater calculated differences than adults. Crystalloid patients exhibited higher urine outputs than colloid patients until colloid was started, suggesting that early over-resuscitation did not contribute to fluid creep. Adherence to our protocol for burn shock resuscitation was excellent overall. Fluid creep exhibited by more seriously injured patients was not due to nurses' failure to follow the protocol. This review has illuminated some opportunities for practice improvement, possibly using a computerized decision support system.     

Fluid resuscitation in neonatal and pediatric hypovolemic shock: a Dutch Pediatric Society evidence-based clinical practice guideline

Objective To develop a clinical practice guideline that provides recommendations for the fluid, i.e. colloid or crystalloid, used for resuscitation in critically ill neonates and children up to the age of 18 years with hypovolemia.Methods The guideline was developed through a comprehensive search and analysis of the pediatric literature. Recommendations were formulated by a national multidisciplinary committee involving all stakeholders in neonatal and pediatric intensive care and were based on research evidence from the literature and, in areas where the evidence was insufficient or lacking, on consensus after discussions in the committee.Results Because of the lack of evidence in neonates and children, trials conducted in adults were considered. We found several recent meta-analyses that show excess mortality in albumin-treated groups, compared with crystalloid-treated groups, and one recent large randomized controlled trial that found evidence of no mortality difference. We found no evidence that synthetic colloids are superior to crystalloid solutions.Conclusions Given the state of the evidence and taking all other considerations into account, the guideline-developing group and the multidisciplinary committee recommend that in neonates and children with hypovolemia the first-choice fluid for resuscitation should be isotonic saline.The work was funded by the ‘Practice Guidelines Program’ at the Academic Medical Centre in Amsterdam. This article is discussed in the editorial available at:     

An international comparison of the cost of fluid resuscitation therapies

ObjectiveFluid resuscitation is a ubiquitous intervention in the management of patients treated in the intensive care unit, which has implications for intensive care unit resourcing and budgets. Our objective was to calculate the relative cost of resuscitation fluids in several countries to inform future economic evaluations.MethodsWe collected site-level data regarding the availability and cost of fluids as part of an international survey. We normalised costs to net present values using purchasing power parities and published inflation figures. Costs were also adjusted for equi-effective dosing based on intravascular volume expansion effectiveness and expressed as US dollars (USD) per 100 mL crystalloid equivalent.ResultsA total of 187 sites had access to cost data. Between countries, there was an approximate six fold variation in the cost of crystalloids and colloids overall. The average cost for crystalloids overall was less than 1 USD per 100 mL. In contrast, colloid fluids had higher average costs (59 USD per 100 mL). After adjusting for equi-effective dosing, saline was ～27 times less costly than albumin (saline: 0.6 USD per 100 mL crystalloid equivalent; albumin 4–5%: 16.4 USD; albumin 20–25%: 15.8 USD) and ～4 times less costly than hydroxyethyl starch solution (saline: 0.6 USD; hydroxyethyl starch solution: 2.5 USD). Buffered salt solutions, such as compound sodium acetate solutions (e.g., Plasmalyte®), had the highest average cost of crystalloid fluids, costing between 3 and 4 USD per 100 mL.ConclusionThe cost of fluid varies substantially between fluid types and between countries, although normal (0.9%) saline is consistently less costly than colloid preparations and some buffered salt solutions. These data can be used to inform future economic evaluations of fluid preparations.     

Sydney ringer: Water supplied by the new river water company

Lactated Ringer's solution has been used for decades in the resuscitation of hypovolemia and hemorrhagic shock. Its origin relates to a serendipitous substitution of water in the London laboratory of Sydney Ringer in the 1880s.A number of controversies have related to the use of lactated Ringer's solution. Some of these have involved the potential exacerbation of lactic acidosis and the question of whether administration of colloid or crystalloid is preferable in severe hypovolemia. The use of hypertonic saline solutions in shock is an issue of current investigative interest.     

Impairment of coagulation by commonly used resuscitation fluids in human volunteers

Background

This study compared the effects of two commonly used resuscitation fluids on whole blood coagulation.

Methods

1000 ml of two resuscitation fluids each (saline and Gelofusine) were given to eight volunteers in a crossover design with a 2‐week washout period. The effect on whole blood coagulation was assessed using the Sonoclot analyzer, a conventional coagulation screen and coagulation markers.

Results

No significant effect was found on whole blood coagulation by giving saline (time to peak clot increased by a mean of 106 s; (95% confidence interval (CI) –140 to 354), whereas Gelofusine delayed the time to peak by a mean of 845 s (95% CI 435 to 1255). By contrast, there was no change in the conventional coagulation screen with either fluid.

Conclusion

It was concluded that some resuscitation fluids have an effect on clot formation that is not shown by the conventional coagulation screen, but is disclosed only if the whole coagulation process is studied.There is an ongoing controversy about the relative merits of different types of resuscitation fluid.¹ In this discussion, the effects of different fluids on coagulation is rarely mentioned, despite coagulopathy often being a problem after large‐volume fluid resuscitation. The origin of this coagulopathy is multifactorial,² and it is usually assumed that resuscitation fluids contribute by cooling the patient and diluting clotting factors. However, there may also be a direct effect owing to an interaction between resuscitation fluid molecules and the coagulation system.Using whole blood coagulation analysis, we have already found a wide variation in the in vitro effects of resuscitation fluids on coagulation, with no simple crystalloid or colloid difference.³ We know that in vitro 0.9% saline has a procoagulant effect at lower dilutions and an anticoagulant effect at higher dilutions, and that Gelofusine has a marked anticoagulant effect.⁴ If this direct effect of a resuscitation fluid on coagulation was also present in vivo, it would influence the choice of fluid given to the bleeding patient in emergency care. This study compares the effects of saline and Gelofusine on whole blood coagulation in human volunteers.     

Colloids vs crystalloids

The choice of colloid or crystalloid solutions for resuscitation of a patient in shock remains controversial. Colloids quickly restore plasma volume along with stabilizing hemodynamics. Almost the entire volume is retained within the vascular space after 1 hour. However, only 8 percent of infused water and less than 25 percent of infused saline are retained in intravascular fluid compartments after 1 hour. When using crystalloids for resuscitation, two to four times as much fluid is required for fluid repletion. The very young or old or persons with cardiac or renal dysfunction may have an increased risk of developing pulmonary edema when crystalloids are administered.     

Is lactate the new panacea for endothelial dysfunction?

Fluid resuscitation in the critically ill is a hot topic. The current strategy of rapid and adequate resuscitation in shock followed by conservative fluid administration is often difficult to achieve with standard crystalloid solutions. Research into alternative intravenous fluids tailored to individual patient needs is required. In the previous issue of Critical Care, Somasetia and colleagues compare the effects of hypertonic sodium lactate with the World Health Organization-recommended strategy of Ringer’s lactate resuscitation in children with severe Dengue, a viral infection for which causal treatment and vaccination are not available. The results not only suggest unimpaired lactate metabolism during shock in children but document improvement in endothelial barrier function, limited coagulopathy, and avoidance of fluid overload with hypertonic sodium lactate. Their study invites several important questions to be answered. Is hypertonicity or lactate per se important for the beneficial effects? Are the metabolic or anti-inflammatory effects responsible? Is the raised lactate in shock an adaptive response? Should reduction in lactate levels be the goal of resuscitation? These questions may trigger further research into the role of lactate and lactate-based intravenous fluids in resuscitation of the critically ill.Dengue fever is the most prevalent mosquito-borne viral illness in humans. In tropical and subtropical countries, an estimated 500,000 patients, mostly children, require hospitalization each year, with overall mortality rate around 2.5%, however reaching up to around 40% in cases with established shock [1,2]. There are four serotypes of the enveloped, single-stranded RNA Dengue virus. Immunity following infection with one serotype does not protect the host from being infected by another serotype and in fact may trigger more severe disease [3,4].The hallmarks of severe Dengue infection, also termed Dengue hemorrhagic fever (DHF) and Dengue shock syndrome (DSS), are mucosal bleeding and vascular leakage syndrome due to complex interplay between the virus, platelets, and immune and endothelial cell activation leading to barrier dysfunction, plasma leakage, hemoconcentration, thrombocytopenia, and coagulopathy [5]. The profound vascular leakage leads to circulatory collapse and accumulation of interstitial fluid with respiratory, cardiac, hepatic, and cerebral function impairment [2]. The molecular events triggered by the virus lead to endothelial activation with type I interferon and pro-inflammatory cytokine production associated with swelling of endothelial cells and shedding of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1) [6]. Although it has been proposed that soluble VCAM-1 (sVCAM-1) levels may reflect severity of DHF/DSS, this remains unproven [7].The World Health Organization (WHO) recommends that patients with DHF/DSS be treated with an immediate volume replacement using isotonic crystalloid solutions, followed by the use of plasma or colloid solutions for profound or continuing shock [2]. The goals of fluid resuscitation include decreasing tachycardia and improving pulse volume, capillary refill time, and end-organ perfusion while correcting metabolic acidosis. During the critical and recovery phase, however, excessive fluid therapy is associated with pulmonary edema, congestive heart failure, massive pleural effusion, and ascites. In this respect, the study by Somasetia and colleagues in the previous issue of Critical Care is a pioneering work [1]. They randomly assigned 50 children either to the standard WHO recommendation-based protocol of fluid resuscitation with Ringer’s lactate (28 mmol/L) or to hypertonic sodium lactate (HSL) solution that contains 504 mmol/L of lactate. Apart from reaching their primary endpoint of reduction in sVCAM-1, suggesting reduced inflammatory activation of the endothelium, the lactate-based regime was associated with several important effects.First, the volume of fluid required in the HSL group was much lower during the 12-hour intervention period to the extent that the overall fluid balance was neutral. This may be related to the following: (a) HSL is a hypertonic solution that may draw interstitial fluid back into the vasculature; (b) lactate as a metabolizable anion may lead to chloride egress from endothelial cells, causing reduction in swelling and improved barrier function [8]; and (c) it was recently shown that lactate by itself has important anti-inflammatory properties that may have reduced inflammatory response and endothelial activation [9].Second, plasma lactate levels actually fell in the HSL group despite a substantial amount of infused lactate. This suggests that these critically ill children had unimpaired lactate metabolism. Consequently, the high strong ion difference of the HSL solution resulted in metabolic alkalosis and hypokalemia, which were similar to HSL effects reported in a study by our group [10].Third, although more rescue starch boluses were given in the observation period (second 12 hours), suggesting that the effect of HSL is short-lived, less blood products were required, implicating a reduction in coagulopathy. The reason for this is unclear but may be related to less hemodilution and higher pH associated with HSL infusion.The study by Somasetia and colleagues was a pilot study with sVCAM-1 as a primary surrogate outcome of limited clinical importance [7]. Despite this, the authors made a substantial contribution to the important field of fluid resuscitation in sepsis, particularly in the pediatric population. The Fluid Expansion as Supportive Therapy (FEAST) study has already challenged the concept that large-volume fluid resuscitation is beneficial in sepsis [11], and this study suggests that by using HSL solution instead of standard fluid therapy, a smaller volume is required, and this could be associated with less coagulopathy while providing useful energetic substrate for vital organs, reduce inflammation, correct acidosis, and end up with a reasonable fluid balance avoiding the ‘Michelin man’ effect (increased interstitial fluid accumulation and peripheral edema). Although the FEAST trial concerned fluid resuscitation in bacterial sepsis and malaria, which have pathogeneses different from those of DHF, endothelial cell dysfunction is common to all. So one may agree with the authors: ‘from a theoretical point of view, the optimal treatment should address both the cause (endothelial dysfunction) and consequence (hypovolemia)’ of increased vascular permeability [1]. This work thus may prompt trials of hypertonic lactate resuscitation in sepsis with the aim to restore vascular permeability. Nevertheless, one needs to take into account the potentially deleterious effects of lactate on immune function in sepsis [12].     

A balanced view of balanced solutions

The present review of fluid therapy studies using balanced solutions versus isotonic saline fluids (both crystalloids and colloids) aims to address recent controversy in this topic. The change to the acid-base equilibrium based on fluid selection is described. Key terms such as dilutional-hyperchloraemic acidosis (correctly used instead of dilutional acidosis or hyperchloraemic metabolic acidosis to account for both the Henderson-Hasselbalch and Stewart equations), isotonic saline and balanced solutions are defined. The review concludes that dilutional-hyperchloraemic acidosis is a side effect, mainly observed after the administration of large volumes of isotonic saline as a crystalloid. Its effect is moderate and relatively transient, and is minimised by limiting crystalloid administration through the use of colloids (in any carrier). Convincing evidence for clinically relevant adverse effects of dilutional-hyperchloraemic acidosis on renal function, coagulation, blood loss, the need for transfusion, gastrointestinal function or mortality cannot be found. In view of the long-term use of isotonic saline either as a crystalloid or as a colloid carrier, the paucity of data documenting detrimental effects of dilutional-hyperchloraemic acidosis and the limited published information on the effects of balanced solutions on outcome, we cannot currently recommend changing fluid therapy to the use of a balanced colloid preparation.     

延迟复苏治疗活动性失血性休克临床探讨

目的：探讨延迟复苏策略治疗重症活动性失血性休克在临床的应用实践。方法：延迟复苏组（A组）,限制输晶体液和胶体液量,扩容更多地依赖输血及血浆,控制目标血压以收缩压80~90 mm Hg（1 mm Hg=0.133 kPa）为允许性低血压;传统复苏组（B组）,不限制输晶体液和胶体液量,快速进行液体复苏。输液以晶体液和胶体液为主,输血及血浆为辅助,不有意控制血压上限。结果：A组抢救成活率显著高于B组。结论：在重症加强护理病房（ICU）临床上认识重症活动性失血性休克特殊性以及治疗的特殊性。应用延迟复苏方法,有望提高该类危重患者的治愈率。     

Systemic complications of fluid resuscitation.

Fluid administration in critically ill individuals is frequently a major component of their therapy. There are important effects on blood pressure and maintenance of cardiac output and oxygen delivery, as detailed elsewhere in this text. There are also potentially negative side effects of this therapy, which have been less well defined. Edema of the gastrointestinal tract has been well described, primarily with crystalloid infusions. Gastrointestinal edema may have very complicated effects on albumin kinetics, fluid flux, and ion flux. It may lead to development of ileus. Increased nasogastric tube output may be incorrectly construed as unremitting obstruction rather than a result of the aforementioned changes and increased crystalloid loads. The relationships of intestinal edema to intestinal absorptive function and diarrhea are less clear. At present, changes in type of fluid infusion or correction of serum albumin level to normal cannot be uniformly recommended. The myocardium, although showing evidence of edema with crystalloid infusion, may appear to benefit from colloidal, osmotically active suspensions in the all too few studies that have been done. To date, there is no study giving evidence of clinically different outcome using a variety of fluids that cause, reduce, or prevent this edema. The presence or absence of myocardial edema may be important in patients who demonstrate decreased ventricular function during sepsis or other disorders in which aggressive fluid administration is routine. Edema of the skin has been associated primarily with decreased oxygen tension. Other studies have shown an association with impaired wound healing or increased risk of infection. A direct causal relationship can only be inferred. We are left with a sense that aggressive fluid resuscitation with crystalloid, although improving oxygen delivery, may have other deleterious effects on organ systems, such as the gastrointestinal tract, myocardium, and integument. The edema resulting from crystalloid administration may lessen or negate the benefits of increased oxygen delivery. Care needs to be taken in interpreting any alteration in organ function with respect to the fluid type and volume being administered. An alternative choice of therapy is lacking at present. The role of colloid has not been as well investigated as that of crystalloid and further study is warranted before any benefits become clear.     

Fluid and electrolyte imbalances after cardiac surgery.

Patients having cardiac surgery experience a myriad of fluid and electrolyte disorders. Cardiopulmonary bypass (CPB) can cause multiple physiologic alterations, including electrolyte disturbances, acid-base imbalances, atelectasis, diminished pulmonary compliance, hemolysis, and thromboembolism. Cardioplegic solutions and induced hypothermia impose alterations in potassium metabolism and pH. The stress of surgery increases catecholamine circulation and augments antidiuretic hormone release, both of which affect fluid and electrolyte equilibrium. Dilution of the circulating blood volume from pump perfusate and volume resuscitation with crystalloid and colloid solutions produce fluid, electrolyte, and hemostatic disorders. Nonpulsatile flow produced by CPB can alter renal function. This article describes the metabolic alterations that are iatrogenically produced by cardiac surgery and the nursing and medical therapies aimed at correcting such alterations.     

Colloids versus crystalloids for emergency patients

Emergency as well as critical care nurses are often responsible for the administration and regulation of fluid resuscitation for their patients. A serious and potentially fatal decline in vital organ performance can often occur as a result of inappropriate volume management. However, emergency and/or critically ill patients who require fluid resuscitation often receive concurrent therapy and monitoring that may have equal or greater impact on the survival and therapeutic end points than does the type of fluid received. These variables have made historical comparisons of crystalloid versus colloid resuscitation difficult. The purpose of this article is to critique three articles that examine crystalloid and colloid resuscitation for patients with various disease processes.     

Maintenance fluid therapy and fluid creep impose more significant fluid,sodium, and chloride burdens than resuscitation fluids in critically ill patients: a retrospective study in a tertiary mixed ICU population

Purpose

Research on intravenous fluid therapy and its side effects, volume, sodium, and chloride overload, has focused almost exclusively on the resuscitation setting. We aimed to quantify all fluid sources in the ICU and assess fluid creep, the hidden and unintentional volume administered as a vehicle for medication or electrolytes.

Methods

We precisely recorded the volume, sodium, and chloride burdens imposed by every fluid source administered to 14,654 patients during the cumulative 103,098 days they resided in our 45-bed tertiary ICU and simulated the impact of important strategic fluid choices on patients’ chloride burdens. In septic patients, we assessed the impact of the different fluid sources on cumulative fluid balance, an established marker of morbidity.

Results

Maintenance and replacement fluids accounted for 24.7% of the mean daily total fluid volume, thereby far exceeding resuscitation fluids (6.5%) and were the most important sources of sodium and chloride. Fluid creep represented a striking 32.6% of the mean daily total fluid volume [median 645 mL (IQR 308–1039 mL)]. Chloride levels can be more effectively reduced by adopting a hypotonic maintenance strategy [a daily difference in chloride burden of 30.8 mmol (95% CI 30.5–31.1)] than a balanced resuscitation strategy [daily difference 3.0 mmol (95% CI 2.9–3.1)]. In septic patients, non-resuscitation fluids had a larger absolute impact on cumulative fluid balance than did resuscitation fluids.

Conclusions

Inadvertent daily volume, sodium, and chloride loading should be avoided when prescribing maintenance fluids in view of the vast amounts of fluid creep. This is especially important when adopting an isotonic maintenance strategy.

     

Fluid therapy and the resuscitation of traumatic shock

Fluid management of the traumatized patient begins with assessment of volume status via palpation of pulses; evaluation of mental status; and measurement of urine output, arterial blood pressure, and central pressures. Intravascular line placement and choice of initial resuscitation fluids should be individualized to the clinical situation, although in most situations a crystalloid solution continues to be the initial fluid of choice. Following initial stabilization, the intravenous fluid administered can be tailored to a given situation, chosen only after the deranged fluid balance is sequentially classified according to alterations of volume, concentration, and composition. Parenteral fluids may be divided into two groups: crystalloids and colloids. The indications, complications, and controversies surrounding various resuscitation modalities have been reviewed.     

Review article: Prehospital fluid management in traumatic brain injury

The early management of patients who have sustained traumatic brain injury is aimed at preventing secondary brain injury through avoidance of cerebral hypoxia and hypoperfusion. Especially in hypotensive patients, it has been postulated that hypertonic crystalloids and colloids might support mean arterial pressure more effectively by expanding intravascular volume without causing problematic cerebral oedema. We conducted a systematic review to investigate if hypertonic saline or colloids result in better outcomes than isotonic crystalloid solutions, as well as to determine the safety of minimal volume resuscitation, or delayed versus immediate fluid resuscitation during prehospital care for patients with traumatic brain injury. We identified nine randomized controlled trials and one cohort study examined the effects of hypertonic solutions (with or without colloid added) for prehospital fluid resuscitation. None has reported better survival and functional outcomes over the use of isotonic crystalloids. The only trial of restrictive resuscitation strategies was underpowered to demonstrate its safety compared with aggressive early fluid resuscitation in head injured patients, and maintenance of cerebral perfusion remains the top priority.