Keywords

FormalPara IFA Commentary (MLNGM)

Trauma patients require careful management of intravenous fluids, given the complexity of decisions involved, often compounded by blood loss and coagulopathy. This chapter focuses on fluid management in trauma patients, providing guidance and recommendations on specific circumstances. The best fluid for a patient may not always be the one that is readily available, and decisions regarding fluid management must consider the need to provide adequate organ perfusion and oxygen delivery.

To achieve this goal, the principles of initial resuscitation in polytrauma patients should limit the use of crystalloids and prioritize early use of blood products, permissive hypotension in selected patients, and early damage control surgery in patients who do not respond to initial resuscitation. The initial choice of fluid should be normal saline for traumatic brain injury patients and balanced salt solution for other patients. Colloids, albumin, and hypertonic saline are not recommended for resuscitation.

After the initial fluid bolus of 1 L, the patient’s response to fluid should be assessed as a rapid responder, transient responder, or minimal/nonresponder. This assessment guides subsequent resuscitation and diagnostic and therapeutic decisions. Overzealous fluid resuscitation in the first 24 h of trauma has been associated with increased mortality, longer duration of mechanical ventilation, and increased risk of intra-abdominal hypertension and abdominal compartment syndrome.

Suggested Reading

  1. 1.

    Wise R, Faurie M, Malbrain MLNG, Hodgson E. Strategies for intravenous fluid resuscitation in trauma patients. World J Surg. 2017;41(5):1170–1183. https://doi.org/10.1007/s00268-016-3865-7. PMID: 28058475; PMCID: PMC5394148.

FormalPara Learning Objectives

After reading this chapter you will be able to:

  1. 1.

    Describe the principles and evolving strategies of resuscitation in polytrauma patients.

  2. 2.

    Describe the clinical signs of shock and relate them to the degree of blood loss.

  3. 3.

    List the different initial resuscitation fluids and determine the most appropriate type and amount of fluid based on recent evidences.

  4. 4.

    Measure the patient initial responses to fluid resuscitation and different patterns of patient responses and its implication in subsequent therapy.

  5. 5.

    Discuss the basis for further fluid management, organ perfusion, and tissue oxygenation in trauma patients.

  6. 6.

    Explain the adverse effects of fluid overload and outline the steps necessary for preventing and managing the cumulative fluid overload.

FormalPara Case Vignette

Mr. K, aged 38, is brought in by the ambulance after a high-speed rollover where a car crashed into a pole. Primary survey at the resuscitation area revealed the patient to be confused but following commands. Vitals recorded were blood pressure (BP) of 90/70 mmHg, pulse rate of 121 beats/min, respiratory rate of 28 breaths/min with oxygen saturation being maintained at 94%, and a visible fracture of the right femur. An appropriate size cervical collar was applied, two 16G IV cannulae were inserted, and 2 L/min oxygen was started via nasal prongs.

Questions and Answers

  • Q1. What is the best fluid type, volume, strategy, and end point of resuscitation?

    A1. A point-of-care FAST scan showed free fluid in the right upper quadrant. Shortly afterwards, the patient became hypotensive and there was a transient response to fluid resuscitation. At this point, the patient was taken by the trauma surgery team for damage control surgery. He was then admitted to the intensive care unit (ICU) for further management. He was started on vasopressor. Arterial blood gas showed metabolic acidosis with a lactate of 3.5 mmol/L.

  • Q2. How should resuscitation proceed so as to restore normal tissue perfusion?

  • Q3. How would you guide fluid maintenance in this patient group?

    A3. On day four, there was an episode of hypotension after stabilization.

  • Q4. What is your fluid management plan in this patient now?

    A4. On day eight, he was conscious, oriented, and hemodynamically stable and given a spontaneous breathing trial but failed. On assessment, the patient was edematous and had a positive cumulative fluid balance of 10 L.

  • Q5. How will you plan to wean from ventilator and extubate?

Introduction

In the care of critically ill trauma patients, resuscitation from hemorrhagic shock is one of the primary tasks. However, it is surrounded by uncertainties as to the correct approach. The best choice of fluid, volume strategy of fluid resuscitation in varied injuries, monitoring during resuscitation, and appropriate end points for resuscitation are all debatable and unclear. Several recommendations have evolved over recent years incorporating the prevailing uncertainties, yet the resuscitation of these patients remains far from optimal. Recent developments have heralded new approaches which appear promising but need robust studies to establish their benefit. The mortality due to hemorrhagic shock continues to remain unacceptably high in the present era. This chapter focuses on the relevant principles of fluid management in major trauma patients and discusses clinical fluid management in the different phases of trauma care—from early fluid resuscitation to stabilization and deresuscitation.

Goals of Early Resuscitation

Major trauma frequently leads to hemorrhagic shock. The loss of a substantial amount of blood initiates sympathetic compensatory responses to preserve cardiac output. Uncontrolled bleeding causes compensatory responses to be overwhelmed, resulting in a fall in cardiac output and decreased blood pressure. In the presence of continuing bleeding, this affects organ perfusion and often causes multiple-organ dysfunction as well as multi-organ failure. Major trauma is also associated with increased capillary permeability that causes intravascular fluids to shift into the interstitial space, appearing as tissue edema. Therefore, if a decrease in intravascular volume is left uncorrected, it may result in irreversible shock and mortality. Fluid resuscitation primarily aims to attain adequate cardiac output to ensure acceptable oxygen delivery and tissue perfusion until the hemorrhage can be controlled. Major trauma patients commonly have coagulopathy, acidosis, and hypothermia as a result of blood loss and the impact of their injury; this pathophysiological state has been shown to be detrimental to patient outcomes. The traditional concept of early and aggressive fluid administration in severe trauma is associated with increased dilutional coagulopathy, acidosis, and hypothermia (Fig. 16.1), often referred to as the deadly triad that may cause secondary problems such as intra-abdominal hypertension and abdominal compartment syndrome, extremity compartment syndrome, ileus, pulmonary edema, and tissue edema. Therefore, achieving a careful balance between organ perfusion and hemostasis is critical for optimal fluid resuscitation in such patients. The major goal of fluid resuscitation in such scenarios is to maintain an acceptable level of organ perfusion while limiting secondary insults that can occur through an overaggressive approach.

Fig. 16.1
A cyclic diagram of severe blood loss effects. The effects are low body temperature, decreased coagulation, blood clotting problems, increased lactic acid in the blood, acidic blood, and decreased heart performation.

Triad of dilutional coagulopathy, hypothermia, and metabolic acidosis. (Source: https://www.jems.com/patient-care/trauma-s-lethal-triad-hypothermia-acidos/)

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The concept of “damage control resuscitation” (DCR) was developed during recent war conflicts in Afghanistan and Iraq. DCR is a systematic approach to severely injured trauma patients and incorporates four major strategies to decrease mortality and morbidity, namely, hemostatic resuscitation, permissive hypotension, damage control surgery, and goal-directed correction of coagulopathy (Table 16.1), to be undertaken simultaneously [1]. Hemostatic resuscitation involves limiting crystalloid use and resuscitation with blood components resembling whole blood as one or two packed red blood cells (PRBCs), one fresh frozen plasma (FFP), and one platelet [2]. The reversal of coagulopathy with hemostatic resuscitation along with prevention of hypothermia and acidosis helps to combat the trauma triad. The concept of hypotensive resuscitation or permissive hypotension involves keeping the blood pressure lower than normal range to avoid aggravation of bleeding while preserving perfusion to vital end organs until bleeding is controlled [3, 4]. This approach avoids the adverse effects of early, large-volume crystalloid resuscitation such as accelerated hemorrhage and dilutional coagulopathy while maintaining circulatory volume and tissue perfusion. A novel potential harmful mechanism of early aggressive fluid resuscitation is the disruption of fragile glycocalyx layer in the endothelium. Endothelial glycocalyx is a thin protein layer which plays a role in vascular integrity and function. Disruption of the layer causes capillary leak of fluid, electrolytes, and albumin into the interstitium that generates edema and evolves to a state of global increased permeability syndrome (GIPS) [3, 5]. This interstitial edema raises the pressure in all major body compartments causing decrease perfusion pressure and progressive organ failure as abdominal compartment syndrome, acute kidney injury, acute respiratory distress syndrome, and compartment syndrome of limbs [5, 6].

Table 16.1 Components of damage control resuscitation
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The primary focus of initial resuscitation is to stop the bleeding and restore intravascular volume. The initial fluid resuscitation and need of blood products may well depend on the estimated severity of hemorrhage. The estimation of blood loss can be via the physiological effects of hemorrhage, and it is divided into four clinical classes of hemorrhagic shock by the American College of Surgeons’ Advanced Trauma Life Support (ATLS) (Table 16.2).

Table 16.2 Signs and symptoms of hemorrhage by class
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Initial Choice of Fluid for Trauma Resuscitation

The ideal fluid should have a composition similar to that of extracellular fluid; it should be isotonic to avoid intracranial volume variation and should not interfere with blood clotting. The fluid should have high volume expansion properties to prevent excessive fluid resuscitation. There is no single fluid solution with all these properties, and hence the ideal fluid choice for resuscitation of trauma patients remains a subject of debate. Given the paucity of ideal solutions, we believe that it is the rate and amount of fluid which causes secondary problems rather than the type of fluid alone. Balanced crystalloids are the preferred fluid choice during the resuscitation phase.

Crystalloids

In trauma patients with hemodynamic instability, fluid resuscitation with crystalloids is the first-line therapy, of which multiple options are available. Normal saline (0.9% saline), a fluid with its osmolarity approaching that of plasma (slightly higher 308 mM.L−1), is the most common fluid administered during resuscitation. As mentioned in Chap. 9, normal saline is a 0.9% preparation of sodium chloride, equivalent to 154 mmol/L Na and Cl. If sodium chloride completely dissociated in solution, the expected osmolality would be two times 154, or 308 mOsm/kg. Interestingly in vivo measured effective osmolality (tonicity) of 0.9% saline of 286 mOsm/L makes it isotonic to plasma, because a small percentage remains nonionized in water. As such, this fits nicely in the normal range of blood osmolality, of 270–290 mOsm/L. However, the so-called normal saline is an unbuffered, normal saline with supra-physiologic chloride content (154 mEq/L). Balanced salt solutions like lactated Ringer’s (Hartmann’s solution), Ringer’s acetate solution, Plasma-Lyte, and Sterofundin with electrolyte compositions closer to plasma are alternatives to isotonic saline. Crystalloid solutions are discussed in greater detail in Chap. 9.

Large-volume resuscitation with normal saline causes chloride overload and hyperchloremic metabolic acidosis. Chloride overload further reduces renal blood flow by instigating renal vasoconstriction and impaired renal tissue perfusion [7]. Balanced salt solutions, on the other hand, have minimal effect on pH and no effect on renal perfusion; hence, they are presumed to be better options during resuscitation. Their limitations are higher cost, interaction with blood products if mixed, and osmolarity slightly lower than plasma (285–295 mOsm/kg). This can have an impact in traumatic brain injury patients (TBI) as they may increase brain water content aggravating cerebral edema.

There are no large trials comparing normal saline and balanced solutions for trauma resuscitation. Most of the data is extrapolated from trials done in other critically ill patients. In the SPLIT trial that randomized ICU patients to receive either 0.9% saline or Plasma-Lyte, Young and colleagues failed to find any difference in the incidence of acute kidney injury (AKI), need for renal replacement therapy, or mortality between two crystalloid groups [8]. The study has been criticized due to its small sample size, the limited amount of fluids administered (median fluid ~2000 mL), and the fact that a major end point, namely, serum chloride levels, was not monitored. Two large single-center trials, the SMART and the SALT-ED trials, examined the utility of balanced solutions compared with normal saline [9, 10]. The SMART trial found a lower composite outcome of death, new renal replacement therapy, or persistent renal dysfunction among critically ill patients in ICU, but the SALT-ED trial performed in the emergency department failed to show a clear benefit. One of the safest and acceptable approaches to trauma fluid resuscitation is to start with normal saline in TBI patients and balanced salt solution in other hemorrhaging patients.

Colloids

Albumin and synthetic colloids are discussed in further detail in Chaps. 10 and 11, respectively. Colloids were initially proposed as a very effective volume expander with an expansion ratio of 1:2–1:3 in favor of colloids compared to normal saline. However, a recent meta-analysis which included studies in perioperative and critical care settings reported an insignificant gain in volume expansion, a volume ratio varying between 1:1.3 and 1:1.6 [11]. The nationwide trauma registry data from 2002 to 2015 looked at the effects of fluid resuscitation with synthetic colloids in severely injured trauma patients [12]. The analysis of early fluid resuscitation with more than 1 L of colloids was linked with an increased requirement for hemodialysis. Synthetic colloids administered at any dose were associated with an increased rate of multiple-organ failure. Annane and colleagues compared colloids with crystalloids for the resuscitation of critically ill patients presenting with hypovolemic shock. The authors didn’t find any difference in 28-day all-cause mortality between the groups and the same was replicated in the trauma subgroup [13].

Hydroxyethyl starch (HES) was one of the most frequently used synthetic colloids. It’s use has shown to be associated with significant coagulopathy and adverse kidney effects when compared with balanced salt solution while being used for resuscitation in septic shock states in intensive care units. However, a recent systematic review failed to find any association between the use of starch solutions and acute kidney injury in the perioperative setting of surgical patients [14]. The concerns about the associated renal injury have led to a decline in its use lately. It also affects the function of von Willebrand factor and impedes the polymerization of fibrinogen. Studies that evaluated hemostasis by viscoelastic assays confirmed that starch infusion resulted in weaker blood clot formation and impaired platelet aggregation than crystalloid or albumin [15].

The SAFE study investigators had demonstrated that albumin as a resuscitation fluid does not interfere with kidney function and coagulation. However, in the subgroup of patients with TBI, 28-day mortality was higher in the 4% albumin group compared to 0.9% saline that persisted at the two-year follow-up. This was attributed to exacerbation of cytotoxic or vasogenic cerebral edema induced by albumin [16, 17]. In conclusion, colloids probably do not confer any major advantage, at least in the early resuscitation of trauma patients.

Hypertonic Solutions

Hypertonic saline (HTS) (e.g., 3% or 6% at a dose of 4 mL/kg/15 min, also called small-volume resuscitation) has been considered with significant interest in trauma resuscitation. There are several postulated theoretical benefits of HTS in trauma resuscitation. It provides volume expansion, causes immune modulation, and offers anti-inflammatory properties. It has also been shown to be effective in the reduction of intracranial pressure (ICP). Its ability to achieve a higher degree of plasma expansion with a smaller volume of HTS makes it an attractive option for hemodynamic resuscitation and in achieving optimal hemostasis during periods of initial hemorrhagic shock. However, HTS has failed to improve patient-oriented clinical outcomes when used as a resuscitation fluid in patients with hemorrhagic shock or TBI [18, 19]. Its administration was even associated with higher mortality in the cohort that was not transfused during the initial 24 h [20]. Authors postulated that HTS concealed the clinical signs of hemorrhage, thus delaying transfusions. In contrast, it has shown to decrease the risk of abdominal compartment syndrome and acute kidney injury in patients with severe burns by limiting the use of large-volume resuscitation with the crystalloids [21].

Penetrating Versus Blunt Injury Versus Head Injuries

For most practical purposes of fluid resuscitation, trauma emergency can be divided into three main categories: penetrating injury, blunt injury, and head injuries; and often there are overlaps such as polytrauma. In the case of penetrating injury patients presenting with hypotension, delay in fluid therapy until surgical intervention improves patient outcome [22]. This “scoop and run” policy permits the systolic BP to be maintained between 60 and 70 mmHg until the patient can be taken to the operating room (OR). After controlling the source of bleeding in the OR, a higher BP should be targeted. A similar restrictive policy is acceptable in blunt traumas where slower infusions are favored over rapid boluses with the aim of maintaining a slightly higher systolic BP of 80–90 mmHg. This restrictive policy is thought to minimize intra-abdominal bleeding while maintaining adequate organ perfusion and reducing the risk of complications like coagulopathy, hypothermia, and intra-abdominal hypertension. In the emergency room, clinical presentation is often complicated and target BP goals frequently need to be tailored depending on comorbidities, the patient’s physiology, and compensatory mechanisms. However, the restrictive and permissive hypotension strategies should not be applied to patients with TBI and spinal injury. Maintaining a systolic BP between 100 and 110 mmHg is a priority in these patients to preserve adequate cerebral perfusion [23].

Initial Trauma Resuscitation Fluid Volume

The volume of fluid and blood resuscitation required to restore circulating volume and maintain tissue perfusion is difficult to foresee on initial evaluation of a trauma patient. For major trauma patients presenting in hemorrhagic shock, most practice guidelines suggest administration of 1 L of warm crystalloid fluid and 20 mL/kg for pediatric patients weighing less than 40 kilograms as a bolus in initial resuscitation [24]. After the initial fluid bolus, the patient’s response to fluid is assessed by vital signs and adequacy of end-organ perfusion and tissue oxygenation. The patient’s response can be divided into three groups: rapid responder, transient responder, and minimal or nonresponder. These responses guide subsequent resuscitation and diagnostic and therapeutic decisions as discussed in Table 16.3 [24].

Table 16.3 Patterns of patients responses to initial fluid resuscitation (isotonic crystalloid of 1 L in adults; 20 mL/kg in children)
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  • The rapid responders are a group of patients who have typically lost less than 15% of the blood volume. They quickly respond to the initial fluid bolus and become hemodynamically stable, without signs of impaired tissue perfusion.

  • Transient responders have ongoing blood loss or inadequate resuscitation and have lost an estimated 15–40% of their blood volume. They respond to the initial fluid bolus followed by slow deterioration. In most of these patients, transfusion of blood and blood products is indicated. It is of paramount importance to recognize these patients as they often require operative or angiographic control of the hemorrhage.

  • Minimal or nonresponders are those patients who fail to respond to bolus crystalloid and blood products administration. This indicates the need for urgent, definitive intervention to control hemorrhage and rule out other causes of shock.

The previous recommendation for initial fluid bolus had been two liters, but this was scaled down due to increasing recognition of harms associated with large-volume resuscitation. Studies have shown that overzealous fluid therapy resuscitation in first 24 h of trauma was associated with increased mortality and significantly higher duration of mechanical ventilation and increased risk of abdominal compartment syndrome in polytrauma patients [25, 26]. Further resuscitation is done with use of blood and blood products and damage control surgery as needed. If blood products aren’t immediately available, a small boluses of crystalloid fluid (250 cc or 4 mL/kg at a time) for the time being in patients with systolic BP <70 mmHg, altered mental status or loss of peripheral pulses may be attempted to maintain tissue perfusion.

Practical Approach to Initial Fluid Resuscitation and Pattern of Responses

  • After initial airway and breathing assessment, two large-caliber (at least 18G) peripheral IV catheters are inserted.

  • Blood samples are drawn for crossmatch and sent for appropriate laboratory and blood gas analyses.

  • The warmed fluid bolus of isotonic crystalloid fluid is administered. The choice of crystalloid would be isotonic saline if there is coexisting TBI or a balanced solution in remaining cases.

  • The usual volume of bolus fluid is 1 L (15 mL/kg) for adults and 20 mL/kg for pediatric patients.

  • The response to initial fluid bolus is critical in deciding an appropriate therapeutic strategy in these patients. As defined by the Advanced Trauma Life Support guidelines, the patient response to initial fluid bolus can be divided into three groups: rapid responders, transient responders, and minimal or nonresponders.

Completion of Resuscitation

Once hemostasis is achieved, the goal of resuscitation shifts to the restoration of blood flow, tissue perfusion, and preservation of organ function. Normalization of vital signs does not necessarily reflect adequate resuscitation. This is true especially in younger patients who often maintain their BP even when they are under-resuscitated. They do so with profound vasoconstriction which can result in hypoperfusion. Resuscitation end points should target microcirculation oxygen delivery indices like lactate, base deficit, and ScvO2 to decrease morbidity and mortality [27]. Serial lactate measurement and lactate clearance provide information regarding adequacy of tissue perfusion and guides further resuscitation. Maintaining normal body temperature and adequate pain relief with systemic analgesia will help in reversing vasoconstriction.

Post-Resuscitation Fluid Management

Fluid therapy after completion of resuscitation is needed to compensate for fluid or blood loss due to wounds, drains, continued capillary leak, fever, and the state of hypercatabolism. Deciding on the appropriate amount and choice of fluid is challenging in this phase as there is greater variability among patients. The requirements of fluid may vary considerably in polytrauma patients and those undergoing major emergency surgical procedures. The dose and choice of fluid have to be individualized based on the estimated deficit. Uncorrected hypovolemia may result in tissue hypoperfusion and worsen organ dysfunction. Overzealous fluid dosing may, however, impede oxygen delivery, wound healing, and homeostasis and compromise patient outcome. The general principle is to prevent excessive fluid administration during this phase while maintaining adequate perfusion. Perhaps the best strategy is to look for fluid responsiveness before giving small aliquots of fluid and monitor response to this fluid including its adverse consequences. Methods of fluid responsiveness are further discussed in Chap. 5.

Deresuscitation

Once stabilization is achieved, active removal of fluid with the use of diuretics and ultrafiltration is commonly warranted especially in patients showing signs of tissue edema, compartment syndromes, or pulmonary complications such as edema, ARDS, or contusions. Persistent positive cumulative fluid balance state is implicated in increased morbidity and mortality in terms of prolonged ICU stay, ventilatory requirements, and delayed discharge [25, 26]. The rationale, different methods, and possible consequences of active removal of accumulated fluid, widely known as deresuscitation, is discussed further in Chap. 25.

Case Vignette

For Mr. K, the patient in the vignette, the best fluid and volume for resuscitation should be 1000 mL 0.9% saline till TBI has been ruled out. Once TBI has been ruled out, the fluid of choice should be a balanced crystalloid. Initial resuscitation end point is to target an SBP >110 mmHg till TBI has been ruled out. Once TBI has been ruled out, SBP target of 80–90 mmHg is acceptable as for any other blunt trauma injury. After achievement of hemostasis, the goal of resuscitation is to restore normal tissue perfusion based on serum lactate levels and other markers of microcirculatory flow. The maintenance fluid is estimated along with consideration of fluid loss from wounds leakage, drains and presence of fever, and hypermetabolic state. The need for further fluid boluses or vasopressors during periods of hypotension will be based on the assessment of dynamic indices of fluid responsiveness. Active deresuscitation will be useful in weaning the patient from ventilatory support.

Conclusion

There has been considerable improvement in our understanding of trauma resuscitation and fluid therapy in the past decade. The goal of our therapy should be directed towards improving the patient’s physiology and tissue perfusion, maintaining normothermia, and minimizing coagulopathy. The most acceptable fluid for initial resuscitation is a crystalloid, preferably a balanced one unless there is suspicion of TBI or spinal injury. The timely administration of blood and blood products in life-threatening hemorrhagic shock remains the cornerstone of therapy. Initial resuscitation targets are variable depending on the nature of the injury and the patient’s response to therapy and needs to be individualized. The current acceptable initial end points of hypotensive resuscitation in the presence of active hemorrhage are target SBP of 60–70 mmHg, 80–90 mmHg, and 100–110 mmHg in penetrating trauma, blunt trauma without head injury, and blunt trauma with head injury, respectively. After initial resuscitation, further fluid therapy should be guided by fluid responsiveness and other physiological parameters. During the recovery phase, a restrictive fluid approach and active removal of accumulated fluid facilitates early extubation and reduces the length of ICU and hospital stay.

Take Home Messages

  • The principles of initial resuscitation in polytrauma patients are limiting use of crystalloids and early use of blood products, permissive hypotension in selected patients, and early damage control surgery in patients who don’t respond to initial resuscitation.

  • The initial choice of fluid is normal saline in traumatic brain injury patients and balanced salt solution in other patients. Colloids, albumin, and hypertonic saline are not recommended for resuscitation.

  • After the initial fluid bolus of 1 L, the patient’s response to fluid is assessed as rapid responder, transient responder, and minimal or nonresponder, and these responses guide subsequent resuscitation and diagnostic and therapeutic decisions.

  • Overzealous fluid resuscitation in the first 24 h of trauma was associated with increased mortality and higher duration of mechanical ventilation and increased risk of ACS.

  • Deresuscitation involves the active removal of excess fluid, usually by diuretic therapy, and may be warranted in patients showing signs of tissue edema, compartment syndromes, or pulmonary complications.