Who Has More Extracellular Fluid Baby or Adult

Background: Physiology

Overview

An understanding of fluid compartments, including the structure and function of the jail cell and capillary membranes and the changes that occur in health and in disease, is key to providing appropriate fluid management. The effective circulating volume is the part of the extracellular fluid that maintains perfusion to tissues. The cornerstone of volume management is to maintain the constructive circulating book to optimize oxygen delivery to tissues early in the disease procedure while fugitive interstitial edema. Having knowledge of the physiologic principles that decide volume distribution—in other words, knowing what happens to the fluid after a volume claiming has been given—tin can influence the type and amount of fluid administered.

Intracellular Versus Extracellular Compartments

In adults, total-body water (TBW) comprises ∼60% of lean trunk weight and therefore is the most abundant component in the human body. This varies based on sex (TBW comprises a higher per centum of lean trunk weight in males than in females) and age (the percentage decreases with age). The variation in h2o weight is due largely to the amount of adipose tissue in the body, which holds significantly less water than musculus. TBW is divided into the extracellular and intracellular fluid compartments. The distribution of water can be remembered past the "ii-thirds/one-tertiary and three-fourths/one-quaternary" concept illustrated in Fig 1. There is considerable variation in TBW in children. Neonates, infants, and children carry a significantly higher percentage of TBW compared with adults due to reduced fat content and increased muscle mass proportion. TBW percentage gradually decreases past toddler age (Fig 1B), mirrored by the increment in intracellular fluid book secondary not simply to muscle growth, but also to decreasing rates of collagen production.

Osmolality, Vascular Barrier, and Integrity

Osmotic forces are the chief determinant of water distribution and motility throughout the torso. Solutes that cannot freely cantankerous the cell membrane exert osmotic force per unit area on that compartment, resulting in fluid shifts across the membrane. Because water freely crosses near all cell membranes, a change in osmolality in i compartment will trigger h2o movement beyond the cell membrane to the side with higher osmolality. This specifically describes the forces that occur between the intracellular and extracellular compartments beyond cell membranes. The adding for serum osmolality is: 2 × [Na⁺] + [urea nitrogen]/2.viii + [glucose]/18. It is important to note that while this adding includes glucose and serum urea nitrogen, both these substances permeate readily across most cell membranes and are ineffective osmoles. Therefore, the virtually abundant extracellular cation, sodium, greatly affects water homeostasis. Command over serum osmolality is maintained past the intricate feedback loop between the hypothalamus and the juxtaglomerular appliance in the kidney. Release of arginine vasopressin secondary to hyperosmolarity detected by osmoreceptors in the anteroventral hypothalamus leads to upregulation of aquaporin channels in the collecting duct of the kidney. Simultaneously, osmoreceptors in the juxtaglomerular apparatus detect changes in solute (ie, sodium) delivery and volume status and regulate the renin-angiotensin-aldosterone centrality to change fluid and sodium retentivity in renal tubules. In periods of volume imbalance, the ii osmoreceptor mechanisms work in tandem with each other and with the sympathetic nervous system to regulate a precise residuum of sodium and extracellular water volume (Fig ii). In small children, susceptibility to volume depletion is increased secondary to immature hypothalamic osmoreceptor function and inadequately developed juxtaglomerular apparatus signaling. Additionally, the college per centum of their body weight in TBW places small children at greater risk of more significant hemodynamic compromise in situations of volume depletion.

The intravascular and interstitial compartments are separated by capillary membranes, and the mechanism of fluid shift differs from that described, where capillaries and small postcapillary venules deed equally the sites of exchange. In 1896, Ernest Starling described the archetype model of vascular bulwark function, specifically that net filtration between plasma and interstitium is determined by physical factors, including hydrostatic pressure, oncotic pressure, and the permeability of the barrier separating the 2. The Starling principle alleged that the vascular barrier function is the sole responsibleness of the unmarried endothelial cell line. All the same, more recent data suggest that the healthy endothelial lining is coated with another barrier called the glycocalyx. The glycocalyx is ∼1 μm in thickness and binds proteins, thereby increasing oncotic pressure level inside the endothelial surface layer and further preventing an egress of fluid into the interstitium. In improver, a gratis space containing minimal oncotic pressure resides just adjacent to the glycocalyx and endothelial layers. A pressure gradient betwixt the glycocalyx and free infinite is generated, which further reduces fluid shifts across the vascular wall. Thus, the glycocalyx, forth with the next endothelial cell layer, forms this double barrier to foreclose tissue edema.

Any form of disruption to the glycocalyx can issue in increased transendothelial permeability and ultimately in interstitial edema. Tumor necrosis factor α (TNF-α) and other cytokines, known to be indicative of systemic inflammation, have been shown to be associated with a subtract in the thickness and breakup of the glycocalyx, leading to increased vascular permeability. Similar cases of glycocalyx degradation and increased vascular permeability have occurred later on ischemia-reperfusion injury. Finally, the release of atrial natriuretic peptide secondary to excessive volume resuscitation can cause impairment to the double barrier, further exacerbating tissue edema.

Boosted Readings

• »

  Chappell D, Jacob Thousand, Becker BF, Hofmann-Kiefer One thousand, Conzen P, Rehm 1000. Expedition glycocalyx. A newly discovered "great barrier reef." Anaesthesist. 2008;57(10):959-969.

• »

  Chappell D, Westphal M, Jacob M. The impact of the glycocalyx on microcirculatory oxygen distribution in critical illness. Curr Opin Anaesthesiol. 2009;22(2):155-162.

• »

  Klinger JR, Tsai SW, Green Southward, Grinnell KL, Machan JT, Harrinton EO. Atrial natriuretic peptide attenuates agonist-induced pulmonary edema in mice with targeted disruption of the cistron for natriuretic peptide receptor-A. J Appl Physiol. 2013;114(3):307-315.

• »

  Ranadive SA, Rosenthal SM. Pediatric disorders of water balance. Pediatr Clin North Am. 2011;58(5):1271-1280.

• »

  Rhem M, Zahler Southward, Lötsch One thousand, et al. Endothelial glycocalyx as an additional bulwark determining extravasation of six% hydroxyethyl starch or five% albumin solutions in the coronary vascular bed. Anesthesiology. 2004;100(5):1211-1223.

• »

  Singh A, Satchell SC. Microalbuminuria: causes and implications. Pediatr Nephrol. 2011;26(xi):1957-1965.

• »

  Strunden MS, Heckel K, Goetz AE, Reuter DA. Perioperative fluid and volume direction: physiologic basis, tools and strategies. Ann Intensive Care. 2011;1(1):ii.

Fluid Types

Overview

Since the first infusion of intravenous fluid in 1832 during the cholera epidemic to nowadays day, when fluids are the about frequently prescribed therapy in the intensive care unit (ICU), the quest for the "best" solution has been a subject of ongoing debate and inquiry.

Crystalloid Solutions

Crystalloids are aqueous solutions of inorganic and small organic molecules and are either hypotonic, isotonic, or hypertonic with respect to plasma. Isotonic crystalloids distribute freely across the vascular barrier; approximately one-fourth of the solution stays within the vascular space, bold an intact vascular barrier. Clinically, this translates to a ane-L sodium chloride (NaCl) solution bolus resulting in a 250-mL expansion of circulating volume. Therefore, large volumes of crystalloids often are needed to maintain intravascular book, potentially at the price of generating interstitial edema. Hypertonic solutions, such as 3% or 7.5% NaCl, often are used in the handling of astringent hyponatremia. Many take advocated for the use of hypertonic saline solution to restore intravascular volume rapidly; however, information practice not support its use as a resuscitation strategy. Similarly, hypotonic fluid (ie, half-normal saline solution) is used for treating hypernatremia or free h2o deficit, simply is not an effective resuscitative fluid.

In improver to tonicity, crystalloids can be defined past their electrolyte makeup. Counterbalanced solutions incorporate a physiologic mixture of electrolytes and buffers in an endeavor to replicate the makeup of plasma. Examples include lactated Ringer'southward solution, Isolyte (B. Braun Medical Inc), and Plasma-Lyte (Baxter). Unbalanced solutions do not comprise actress electrolytes or addition of a buffer. NaCl solution is the typical unbalanced solution. A summary of the various crystalloid solutions can be found in Table 1. For years, internal medicine specialists take favored the use of NaCl solution as a resuscitation fluid due to concerns that electrolytes added to balanced solution might be harmful in patients with kidney harm who cannot handle, for instance, a potassium load. However, big-book resuscitation with NaCl solution results in hyperchloremic metabolic acidosis, which now has been shown to have deleterious consequences. In studies of both animals and humans, excess extracellular chloride is associated with increased afferent arteriolar resistance and subsequent reduced cortical perfusion and diminished glomerular filtration rate. In a surgical study of open-abdomen patients that compared 0.9% NaCl to Plasma-Lyte solution, major complications, including an increased risk of patients requiring renal replacement therapy (RRT), was observed in the chloride-liberal group. A big prospective sequential-period pilot written report compared a chloride-liberal arroyo versus a chloride-restricted regimen through patients' entire ICU stays. Results demonstrated an increased incidence of astute kidney injury (AKI) and RRT in the chloride-liberal grouping.

Table one Crystalloid Solutions

	Na+ (mEq/L)	K+ (mEq/L)	Ca++ (mEq/L)	Mg++ (mEq/Fifty)	Cl− (mEq/L)	Buffers (mEq/Fifty electrolyte)	Glucose (g/L)	pH	POsm (mOsm/L)
Plasma	141	4.5	v	2	103	Bicarbonate, 26; protein, 16	0.7-1.i	seven.4	290
Isotonic
Normal saline	154	—	—	—	154	—	—	6.0	308
Lactated Ringer's solution	130	4	4	—	109	Lactate, 28	—	half-dozen.five	274
Plasma-Lyte	140	5	—	3	98	Acetate, 27; Glucose, 23	—	vii.4	294
Hypotonic
DfiveW	—	—	—	—	—	—	fifty	4.five	252
D5W ½ NS	77	—	—	—	77	—	fifty	5.0	406
Hypertonic
vii.5% NaCl	one,284	—	—	—	i,284	—	—	vi.0	2,568

Abbreviations: Ca⁺⁺, calcium ion; Cl⁻, chloride ion; D₅Westward, 5% dextrose; D_vWestward ½ NS, 5% dextrose in one-half-normal saline; K⁺, potassium ion; Mg⁺⁺, magnesium ion; Na⁺, sodium ion; NaCl, sodium chloride; POsm, plasma osmolality.

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Due to concerns about the ability of neonatal and infant kidneys to handle high-solute load, hypotonic resuscitative fluids traditionally accept been used for restoring adequate circulating effective volume. All the same, high incidences of hyponatremia and hypoglycemia warranted investigation and comparing with other crystalloid solutions. Isotonic salt solution and isotonic salt solution with dextrose have been demonstrated to reduce the number of electrolyte imbalances (primarily hyponatremia and hypoglycemia) in resuscitation in children. The recent FEAST (Fluid Expansion equally Supportive Therapy) Study received worldwide attention by examining resuscitation of more than 1,000 Kenyan, Tanzanian, and Ugandan children presenting with astringent infection (∼threescore% malaria) using either normal saline solution bolus, albumin bolus, or no bolus and reported increased mortality in children receiving fluid boluses versus no bolus. Chiefly, the crusade of death in patients who received the 20- to 40-mL/kg bolus fluids could not be linked to hypernatremia, hyperchloremia, edema, or whatsoever direct issue from resuscitative fluids. Unfortunately, randomized data regarding the use of more counterbalanced salt solutions (ie, Plasma-Lyte) versus pure table salt solution are unavailable.

Given the body of evidence, the authors of this review recommend the utilise of balanced over unbalanced crystalloid solutions. All the same, certain clinical scenarios crave individual consideration. Patients with cerebral edema or traumatic brain injury cannot tolerate even relatively hypotonic solutions due to the risk of cellular swelling. Therefore, lactated Ringer's solution, by the nature of its low sodium content, is contraindicated in these patients. In patients at risk of cerebral swelling, we recommend a balanced isotonic solution when resuscitation is necessary. Balanced solutions also should be avoided in patients with alkalemia or astringent hyperkalemia. Last, utilize of lactated Ringer'south solution requires intact liver function to convert lactate into bicarbonate and therefore is not recommended in patients with meaning liver dysfunction. In children, there currently is not enough evidence to support routine utilise of counterbalanced salt solutions over unbalanced salt solutions, though pure physiologic data obtained from animal models indicate that unbalanced solutions could exist even more than detrimental to children than they are to adults.

Colloid Solutions

Colloids are homogenous noncrystalline substances that incorporate large molecules. In theory, colloids accept a greater capacity to remain inside the intravascular space and therefore restore hemodynamics with smaller quantities of volume infused. Colloids in clinical exercise include human plasma derivatives (albumin, fresh frozen plasma, and blood) and semisynthetic colloids (starches, gelatin, and dextran). Albumin has been used for resuscitating hemodynamically unstable patients for decades. It achieved its greatest popularity after its use in Pearl Harbor victims, in which resuscitative goals were achieved efficiently. Albumin is the most costly of colloid solutions and, equally a human body production, contains a very small gamble of infectious manual. It is bachelor in 5% (50-m/Fifty) and 25% (250-g/L) solutions and most often is given in a 250-mL followed past a 50-mL volume. Certain religious groups (eg, Jehovah's Witnesses) preclude its utilize. Hydroxyethyl starches (HESs) are the almost widely used semisynthetic resuscitation fluids. Examples include Volulyte (Fresenius Kabi), Hespan (B. Braun Medical Inc), and Voluven (Hospira). HESs are described by their average molecular weight (130-200 kDa) and degree of molar substitution (ie, the proportion of glucose units on the starch molecule replaced by hydroxyethyl units; typically 0.35-0.5). An HES is described further by its concentration in percentage (ie, grams per 100 mL). For case, vi% HES 130/0.4 contains 6% solution of 130-kDa molecules with 0.iv% of the glucose molecules substituted. HESs accept a lower cost per unit of measurement compared to albumin. Dextrans are high-molecular-weight D-glucose polymers that are biosynthesized commercially from sucrose. They are described by average molecular weight: dextran forty and dextran lxx. Dextrans are rarely used in adults. Gelatins are prepared past hydrolysis of bovine collagen. Due to concerns about coagulopathy and haemorrhage, gelatins were withdrawn from the market in the United States in 1978.

Crystalloid Versus Colloid Solutions: The Data

Despite decades of research and study, there has yet to be a big randomized controlled trial to demonstrate that one blazon of fluid is superior to the other. Colloid supporters focus on the large volume of crystalloid needed to achieve intravascular resuscitation goals. Those who favor crystalloids point to the potential side furnishings of colloids, including hematologic derangement and adverse drug reaction, also as the higher cost. As stated, under healthy conditions, colloids are too large to permit passage beyond the capillary membrane and thus restore circulating volume efficiently. However, in the setting of inflammatory atmospheric condition and vascular barrier breakdown, the distribution of colloids looks very similar to that of crystalloids because both drift from the vascular compartment into the interstitial infinite. This physiologic principle likely is the reason that few studies tin can demonstrate superiority of 1 fluid over the other.

Albumin Versus Crystalloids

As the main determinant of oncotic pressure and driver of fluid distribution betwixt compartments in the human trunk, albumin has nifty appeal every bit a resuscitative fluid. Albumin was a staple for volume resuscitation until a meta-analysis in 1998 showed that it was associated with increased mortality. Opinions changed again later publication of the Safe (Saline Versus Albumin Fluid Evaluation) trial in 2005 in which survival, number of days spent in the ICU and hospital, and days spent on mechanical ventilation after receiving 4% albumin versus 0.ix% NaCl solution were shown to exist similar. Subsequent trials have demonstrated albumin'south rubber. In a SAFE subgroup analysis, patients with severe head injury had worse outcomes when treated with albumin, whereas patients with severe sepsis showed some degree of comeback with albumin compared with saline. Albumin should not be given to patients with traumatic brain injury for this reason. Albumin is indicated in spontaneous bacterial peritonitis as another trial demonstrated a do good of albumin to survival of cirrhotic patients with the status. Finally, in dialysis patients who require large-book ultrafiltration, a 250-mL bolus of v% albumin tin can exist invaluable in order to maintain mean arterial pressure. In several minor studies, primarily limited to patients with malaria and dengue fever in resources-poor areas, albumin appeared to exist associated with lower overall bloodshed than saline solution when used as fluid of option for resuscitating critically sick children. Unfortunately, there are no current controlled studies examining colloid versus crystalloid resuscitation in children with sepsis or astringent hypovolemia in adult nations.

Starch Versus Crystalloids

HESs have been under increasing scrutiny in contempo years. In 2008, the VISEP (Efficacy of Volume Exchange and Insulin Therapy in Severe Sepsis) trial showed that patients who received 10% pentastarch (HES 200/0.5) solution were twice as probable to develop AKI and trended toward increased mortality. Subsequent trials, including 6S (Scandinavian Get-go for Severe Sepsis/Septic Shock) and CHEST (Crystalloid Versus Hydroxyethyl Starch Trial), compared lower weight HES with crystalloid solutions and again showed an association betwixt HES exposure and the need for RRT. As a result of these findings, a European task force on colloid therapy recommends that starch solutions not be used outside the context of clinical trials. The present Surviving Sepsis Entrada states that fluid resuscitation should begin with crystalloid, albumin should be considered in patients who continue to crave substantial amounts of crystalloid, and HES should be avoided. Combining the bachelor bear witness, guidelines, and costs, we favor the use of counterbalanced crystalloid solution with sparing apply of albumin for the conditions outlined.

Though less expansive, results from studies in children comparison unbalanced to counterbalanced electrolyte solutions mirror information obtained from adult studies. For case, comparison of HES (HES 130/0.42/6:1) in normal saline solution (ns-HES) to counterbalanced common salt solution (bal-HES) for perioperative resuscitation demonstrated a significantly college incidence of hyperchloremia in the ns-HES grouping and improved condom for bal-HES use in neonates and pocket-size infants.

Boosted Readings

• »

  Akech Southward, Lederman H, Maitland M. Pick of fluids for resuscitation in children with astringent infection and shock: systematic review. BMJ. 2010;341:c4416.

• »

  Bayer O, Reinhart K, Kohl Grand, et al. Furnishings of fluid resuscitation with synthetic colloids or crystalloids alone on stupor reversal, fluid balance, and patient outcomes in patients with astringent sepsis: a prospective sequential analysis. Crit Care Med. 2012;40(9):2543-2551.

• »

  Brunkhorst FM, Engel C, Bloos F, et al; German Competence Network Sepsis (SepNet). Intensive insulin therapy and pentastarch resuscitation in astringent sepsis. Northward Engl J Med. 2008;358(2):125-139.

• »

  Cochrane Injuries Grouping Albumin Reviewers. Human albumin administration in critically ill patients: systematic review of randomized controlled trials. BMJ. 1998;317(7153):235-240.

• »

  Chowdhury AH, Cox EF, Francis ST, Lobo DN. A randomized, controlled, double-blind crossover study on the furnishings of 2-Fifty infusions of 0.9% saline and Plasma-Lyte R 148 on renal blood flow velocity and renal cortical tissue perfusion in salubrious volunteers. Ann Surg. 2012;256(1):eighteen-24.

• »

  Legrand 1000. Fluid resuscitation does not meliorate renal oxygenation during hemorrhagic stupor in rats. Anesthesiology. 2010:112(1):119-127.

• »

  Maitland K, Kiguli S, Opoka RO, et al; on behalf of the FEAST Trial Group. Mortality afterward fluid bolus in African children with severe infection. N Engl J Med. 2011;364(26):2483-2495.

• »

  Myburgh JA, Finfer Southward, Bellomo R, et al; CHEST Investigators. Hydroxyethyl starch or saline for fluid resuscitation in intensive care. N Engl J Med. 2012,367(twenty):1901-1911.

• »

  SAFE Study Investigators. A comparison of albumin and saline for fluid resuscitation in the intensive care unit. North Engl J Med. 2004;350(22):2247-2256.

• »

  Shaw AD, Bagshaw SM, Goldstein SL, et al. Major complications, mortality, and resource utilization afterward open abdominal surgery: 0.nine% saline compared to Plasma-Lyte. Ann Surg. 2012;255(5):821-829.

• »

  Sort P, Navasa Grand, Arroyo V, et al. Event of intravenous albumin on renal damage and mortality in patients with cirrhosis and spontaneous bacterial peritonitis. N Engl J Med. 1999;341(6):403-409.

• »

  Sumpelmann R, Witt L, Brutt M, Osterkorn D, Koppert Due west, Osthaus WA. Changes in acrid-base, electrolyte and hemoglobin concentrations during infusion of hydroxyethyl starch 130/0.42/six:1 in normal saline or in balanced electrolyte solution in children. Paediatr Anesthesth. 2010;20(i):100-104.

• »

  The 6S Trial Group and the Scandinavian Critical Care Trials Grouping; Perner A, Haase N, Guttormsen AB, et al. Hydroxyethyl starch 130/0.42 versus Ringer's acetate in severe sepsis. N Engl J Med. 2012;367(2):124-134.

• »

  Yunos MM, Bellomo R, Hegarty C, Story D, Ho L, Bailey Thou. Association between a chloride-liberal vs chloride-restrictive intravenous fluid administration strategy and kidney injury in critically sick adults. JAMA. 2012;308(15):1566-1572.

Fluid Management

Targets of Fluid Resuscitation

Securing adequate intravascular book and ensuring optimal perfusion is the primary goal of resuscitation in critical care management. The study by Rivers et al demonstrated that early resuscitation using a goal-directed algorithmic approach improved survival. Although this study has not been validated in a multicentered randomized trial (currently in progress) and many aspects of an early goal-directed therapy protocol have been contested, the importance of recognizing inadequate tissue perfusion and oxygen debt early on is emphasized by this written report'south findings. The fourth dimension-honored method of assessment is based on physical findings, including tachycardia, hypotension, dry mucous membranes, altered mentation, and decreased urine output, are not reliable indicators of intravascular volume. Hypotension is a late indicator of stupor and reflects failure of compensation or book loss > twenty%. Hypotension likewise may reflect pure vasodilation (eg, a side effect of anesthesia) and not volume depletion. In the trial past Rivers et al, boilerplate hateful arterial pressure level in the early on goal-directed therapy group was 76 mm Hg, while the control group'due south was 76 mm Hg, and yet lactate values were > 4 mEq/50, indicating hemodynamic compromise. Urine output is non a reliable indicator either, peculiarly in a setting in which renal blood catamenia alone may non be the cause for oliguria, for case, sepsis-induced AKI.

The principal target of resuscitation in children may simply be timely resuscitation. Unfortunately, volume correction in children offers several unique challenges that are not nowadays in adults. Robust data, starting with a landmark study by Carcillo et al demonstrating a marked improvement in survival in patients with septic shock who received 40 mL/kg of fluid in the starting time hr versus those who did not, support instituting early on and rapid correction of volume deficit in children. More recent retrospective studies published in the by 3-five years support the use of early on and rapid infusion of fluids. Unfortunately, rapid infusion of fluids in children oftentimes is easier said than done. Catheter properties limit the speed of fluid commitment secondary to Poiseuille's law, which states that resistance is inversely proportional to the radius to the fourth power, a concrete principle that becomes pregnant with the 20-, 22-, and 24-gauge peripheral lines that sometimes are necessary in modest children presenting in extremis. Additionally, this assumes that admission can exist obtained readily, which oftentimes is not the example in a small unstable patient. Second, the availability of proper infusion equipment is not widespread. The rapid infusers that are used with some regularity in adult medicine are not ordinarily used outside of tertiary-care pediatric trauma bays, operating theaters, and ICUs. Knowledge of the speed of fluid delivery of standard intravenous fluid pumps also is defective (eg, about providers would be unaware that a 20-mL/kg bolus in a kid weighing 15 kg would take eighteen minutes to complete for a pump running at "maximum": 999 mL/h). Finally, the need to obtain access and institute fluids rapidly is not universally appreciated in pediatric care, an oversight that global sepsis and shock recognition movements are now addressing.

Clinical examination plays a relatively larger office in resuscitating children. Cess of volume and oxygenation debt by thorough exam of the critically ill child consists of a precise time-stamped inspection of perfusion, capillary refill, pare temperature, skin turgor, mucous membranes, lung auscultation, cardiac examination, mental status examination, and vital signs. Owing in part to the inability to obtain reliable invasive measurements (described in some detail next), pre- and post- examinations of children with fluid resuscitation rest on the cornerstones of changes in these physical test findings.

Unlike concrete signs and symptoms, using surrogates of oxygen delivery, including mixed venous oxygen saturation (Svo ₂), fundamental venous oxygen saturation (Scvo ₂), and serum lactate concentration, better represents the imbalance between the body's metabolic demands and the adequate commitment of oxygen to body tissues. The Svo ₂ measurement is acquired from the distal port of a pulmonary artery catheter (PAC). Oxygen consumption exceeding its supply or oxygen delivery existence compromised reduces subsequent oxygen venous return to the correct side of the heart. An Svo ₂ < 65% (reference range, 65%-75%) reflects an imbalance. An Scvo ₂ level obtained from the distal port of a subclavian or internal jugular central catheter can act as a surrogate for the PAC-derived Svo ₂. Although the two values (Svo ₂ and Scvo ₂) are non equivalent, they have been shown to correlate well. Scvo ₂ < 70% denotes inadequate oxygen delivery and should trigger an intervention. High serum lactate concentration and the inability to clear this lactate can reverberate mitochondrial dysfunction, frequently as a consequence of inadequate oxygen delivery. As demonstrated by the written report past Rivers et al, a high lactate level can occur even in the setting of normal blood pressure and heart rate, and therefore one should have a very depression threshold for obtaining a lactate level in a patient who meets systemic inflammatory response syndrome criteria. If lactate level is high (in general we use a cutoff of 2.0 mmol/Fifty), fluid resuscitation followed by rechecking the value six hours later to ensure clearance is a reasonable arroyo. Studies have shown that lactate clearance ≥ 10% is associated with improved outcomes and is the basis for this strategy.

Assessment of Fluid Resuscitation Targets

Overview

Given adequate hemoglobin and oxygen saturation levels, cardiac output is the main determinant of oxygen delivery. Therefore, fluid management should be based on whether giving a bolus of fluid infusion augments cardiac output and thus improves perfusion and oxygen delivery (ie, whether cardiac output is fluid responsive). This relationship between preload and cardiac performance is depicted by the Frank-Starling curve, whereby a modify in preload will produce a significant alter in cardiac output only if both ventricles operate on the ascending limb of the Frank-Starling curve (Figs 3 and iv). Conversely, if preload value is depression, yet operates on a flat portion of the Frank-Starling curve, volume expansion will not improve cardiac performance and will but contribute to volume overload. It is this physiologic concept that governs why a static value of preload does not predict the extent that stroke volume volition respond to a book challenge.

Effigy 3 Patient A has a steeper Starling curve than patient B. Although patients A and B have the same initial preload value and identical changes in preload (ie, fluid bolus), patient A has a greater increase in stroke volume (SV) than patient B. Patient A is said to be "book responsive."

Reproduced from Davison & Junker ("Advances in critical intendance for the nephrologist: hemodynamic monitoring and volume direction." Clin J Am Soc Nephrol. 2008;3[ii]:554-556) with permission of the American Social club of Nephrology.

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Figure 4 Patient C is on the steep portion of the curve. Patient D is on a apartment portion. Identical changes in preload (ie, fluid bolus) issue in different stroke volumes (SVs).

Reproduced from Davison & Junker ("Advances in critical intendance for the nephrologist: hemodynamic monitoring and volume direction." Clin J Am Soc Nephrol. 2008;3[ii]:554-556) with permission of the American Guild of Nephrology.

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In children, the response of the myocardium to volume resuscitation is different than in adults. The myocardium in neonates and infants is immature secondary to numerous central properties: a lower contractile to noncontractile ratio, unlike shape (more circular than elongated/fibrillar), less extracellular matrix elements that confer more tensile strength, decreased myocardial compliance, and less set regulation of calcium current for depolarization. Though the Starling mechanism is intact, the bend is shifted to the left and requires less volume loading to achieve higher force per unit area. In amass, volume loading the young myocardium leads to a relatively decreased effect on augmenting cardiac output compared to the mature heart. In improver, the maturation procedure and relative compliance of the ventricles, along with intraventricular dependence, change dramatically in the first year of life. Though the correct ventricle is always more than compliant than the left ventricle, the relative abundance of contractile elements in the correct ventricle decreases significantly relative to the left within the first three months of postnatal development. Finally, it is of import to recognize the inverse relationship of center rate and stroke volume (or rather, the incomplete changed human relationship) in neonates and infants. Because the myocardium is limited in tensile strength, neonatal and babe hearts are more than dependent on heart rate as a means to augment cardiac output. Taken together, backdrop of the myocardium are important to recognize because a meaning proportion of mortality from shock and volume depletion in children occurs in the neonatal flow.

Static measurements

Static markers of preload include pulmonary artery apoplexy pressure (or "wedge") and cardinal venous pressure. Despite their common use in the disquisitional care setting, these parameters are poor surrogates of volume status and fail to predict fluid responsiveness, as demonstrated by numerous studies. In clinical practice, central venous pressure is used as a surrogate for right atrial and correct ventricular volumes. Also, in theory, pulmonary artery occlusion pressure represents the volume of the left side of the centre. Utilise of these filling pressures equally a parameter of volume status assumes a constant relationship between pressure and volume. Nonetheless, at that place are several clinical scenarios in which this relationship is contradistinct. In the noncompliant "stiff" heart, cardinal venous pressure and pulmonary artery occlusion pressure may be elevated even if the ventricles are underfilled. The high pressure values would point that the patient is book replete when in authenticity, cardiac performance may yet benefit from volume. External pressures, including high ventilator pressures, abdominal compartment pressures, and vascular compliance, can alter the relationship between central venous pressure, pulmonary artery apoplexy pressure, and ventricular volume, making them an inaccurate gauge of volume condition. Use of cardinal venous pressure level measurement to gauge fluid dynamics in children outside the immediate postoperative congenital cardiac surgery setting has no literature support. In addition, the relatively higher pressure level of the right ventricle in neonates and infants (vs the left as a function of age) affects the reliability of the static central venous pressure level measurement.

We strongly recommend against the use of static preload markers to define book condition or guide resuscitation.

Dynamic measurements

Dynamic markers consist of variations in stroke book and arterial pressure that issue from middle-lung interactions during positive pressure ventilation. Many studies have documented that these parameters ameliorate predict whether book assistants will improve cardiac performance. Mechanistically, dynamic measurements are acquired equally follows. With each positive pressure jiff, at that place is a decrease in venous return. If the correct ventricle is preload dependent, there also will be reduced right ventricular outflow. In that location is a subsequent decrease in left ventricular outflow (subsequently a few cardiac cycles, given the ii-second transit fourth dimension for blood to pass through the lungs). The opposite occurs during exhalation: venous return is increased and cardiac output is amplified. This circadian variation in stroke volume and blood pressure is most pronounced when stroke volume is preload dependent. Therefore, high variations suggest that hemodynamics will benefit from volume expansion. Clinically, these markers include systolic force per unit area variation, pulse force per unit area variation, and stroke volume variation. An example of this physiologic concept is depicted in Fig v. These values tin be measured on an arterial wave form tracing (systolic pressure variation and pulse pressure variation) or calculated and displayed continuously by hemodynamic devices (described next). At our institution, nosotros use stroke volume variation as a guide to volume expansion. Stroke volume variation greater than 10%-13% indicates that the patient is fluid responsive. If a patient has a stroke volume variation < 10% and cardiac output unresponsive to volume, that patient's hypotension would be managed with either vasopressors alone or inotropes, depending on cardiac role (Fig six).

Figure v Dynamic markers. Pulse pressure (PP) variation relative to tiptop airway pressure level (Manus) during inspiration and expiration.

Reproduced from Davison & Junker ("Advances in critical treat the nephrologist: hemodynamic monitoring and volume management." Clin J Am Soc Nephrol. 2008;3[two]:554-556) with permission of the American Society of Nephrology.

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The use of dynamic markers to predict fluid responsiveness has limitations. These markers are near authentic when used in a mechanically ventilated patient with consistent breaths, which usually occur during deep sedation or paralysis. Few studies have validated its utilize in spontaneously breathing patients. Similarly, in the open-chest patient, ventilator-induced variation in stroke volume loses its accuracy. Stroke volume variation is not accurate in patients with arrhythmias.

Dynamic markers of fluid responsiveness have not been assessed fairly in infants, children, and adolescents. Pulse pressure variation and systolic force per unit area variation analysis in neonates and infants is discrepant from children and adolescents secondary to the differences in chest wall elasticity and lung compliance as a function of age.

Other functional dynamic measurements

Ii other dynamic mechanisms by which fluid responsiveness tin be measured include the passive leg enhance and variation in inferior vena cava (IVC) bore. During the passive leg enhance exam, a recumbent patient raises the lower extremities above the eye, which increases right and left cardiac preload. If no other monitoring device is present, the effect of passive leg heighten on claret pressure and center rate is used to guide the decision of whether more fluid is indicated. The passive leg raise test reproduces the effects of a volume claiming and therefore besides plays a therapeutic function. The passive leg enhance examination has proved accurate in nonintubated patients, which differentiates it from the other dynamic parameters. The passive leg raise examination cannot be performed in immobilized patients (eg, those who accept traumatic brain injury or open up abdomen). IVC diameter measured past echocardiogram is some other method to measure fluid responsiveness. Similar the other dynamic parameters, variation in IVC diameter depends on the variation in venous render as a upshot of changes in thoracic pressure level during mechanical ventilation. Variation in IVC diameter is calculated equally the change in IVC bore during inspiration compared with expiration (approximately >20% variation indicates book responsiveness). Measuring IVC bore variation requires echocardiography, which is highly dependent on operator skill. Neither passive leg raise exam results nor IVC bore variation can be measured in a continuous fashion and therefore are not useful for ongoing assessment of hemodynamic instability. Tests of reliability for IVC bore measurement in children accept non been performed and informal assessments of interuser consistency demonstrate a lack of appropriate standards. However, in children, in lieu of a passive leg heighten examination, direct force per unit area applied to the inferior surface of the liver edge often is used as a test of volume responsiveness.

Devices Used for Fluid Management at the Bedside

Pulmonary Artery Catheter

Monitoring devices that display cardiac output and facilitate the measurement of volume responsiveness can allow for more precise resuscitation and minimize unwanted side furnishings. The gold standard for measuring bedside cardiac output is the PAC. The PAC uses the thermodilution technique to calculate cardiac output, and it is the mechanism against which all other devices are measured. Central venous pressure level, right atrial pressure, pulmonary artery pressures, pulmonary artery apoplexy pressure, and Scvo _two also can be obtained from the PAC. Newer fiberoptic PACs let for continuous cardiac output monitoring, which adds significant clinical value when monitoring trends and changes in intervention. Use of PACs has declined in the past xx years for ii major reasons. First, despite a big body of research, the PAC has never been shown to better outcomes. Second, the advent of newer devices that are less invasive and provide dynamic parameters to appraise volume responsiveness are making the PAC increasingly obsolete. Though no bear witness demonstrates proven efficacy of the PAC at reducing mortality beyond the wide range of critically sick children, there also is no solid testify indicating an increase in mortality or complications. The available data support using PACs in select children (those with pulmonary hypertension and refractory shock). Pediatric critical care practitioners continue to use PACs, though at lower numbers, driven past clinical context.

Less Invasive Hemodynamic Devices

Echocardiography

Echocardiography is a noninvasive technique that uses ultrasound waves to generate real-time images of the heart. Information technology is used increasingly by intensivists to gain a snapshot of ventricular role and volume status. It rarely is used in a continuous fashion outside the operating room and therefore has its limitations for ongoing direction of critically ill patients.

Esophageal Doppler

This technique estimates aortic blood flow through a Doppler ultrasound inserted into the esophagus. It is based on the physiologic concept that the velocity of claret flow through the aorta is inversely proportional to aortic bore and directly related to flow. This technique requires that the patient be intubated on insertion and that flow is laminar throughout the aorta. Turbulent menstruum secondary to atherosclerosis or an aneurysm will misconstrue the calculations of cardiac output. This technique as well relies heavily on operator skill for proper placement of the device in the esophagus. Despite these drawbacks, information propose that esophageal Doppler is a reliable mensurate of continuous cardiac output.

Thoracic electrical bioimpedance

Bioimpedance is the electric resistance of the thorax to an alternating electrical electric current transmitted through the chest. This is accomplished by 8 electrodes placed on the patient's thorax and continued to the thoracic electric bioimpedance device. The patient'southward cardiac output is calculated using the impedance of the thoracic aorta, which varies with blood menses. Thoracic electrical bioimpedance is noninvasive; yet, it loses accuracy in the settings of pulmonary edema, pleural effusions, and chest wall edema due to the fluid interference. Studies have not demonstrated that thoracic electrical bioimpedance is an accurate mensurate of cardiac output; it should be used in only a select set of patients.

Transpulmonary thermodilution

The transpulmonary thermodilution technique uses thermodilution similar to that of the PAC. Nonetheless, information technology requires utilize of a standard central venous catheter in the internal jugular or subclavian vein, as well as a distal thermistor tip in the femoral artery. Cold injectate is infused into the fundamental line and the temperature change as measured in the downstream femoral artery thermistor is used to calculate cardiac output. Assuming minimal loss of injectate and merely one laissez passer from the proximal to distal thermistor, this is an accurate mensurate of cardiac output. A unique feature of the transpulmonary thermodilution technique is that it also allows for adding of global end-diastolic book and extravascular lung water, which reflect cardiac filling and pulmonary edema, respectively. Studies have shown this technique to be a reliable measure of cardiac output in the critically ill patient population.

Lithium dilution

In this technique, a bolus of lithium is injected into a venous catheter. Blood so is drawn from a distal arterial catheter that contains a lithium sensor. The dilutional curve over fourth dimension is used to judge cardiac output. Dissimilar the transpulmonary thermodilution technique, lithium dilution does not require a central venous catheter, but it requires arterial access and is dependent on accurate sodium and hemoglobin concentrations. Lithium dilution is contraindicated in patients receiving lithium therapy, those who weigh <40 kg, and those who are pregnant. Lithium dilution as well can calculate extravascular lung h2o and compares well when measured against other thermodilution techniques.

Pulse contour assay

Pulse contour assay is a unique monitoring system that displays cardiac output and cardiac alphabetize, stroke volume and stroke volume alphabetize, and the dynamic mark stroke volume variation, all in a continuous fashion. Pulse contour analysis is based on the notion that the pulse pressure arterial waveform is proportional to stroke volume and inversely related to compliance of the vessel. Cardiac output is calculated from the analysis of the pulse contour. PICCO (Pulsion Medical Systems), PulsCO (LidCO Ltd), and FloTrac (Edwards Lifescience LLC) are the 3 pulse contour analysis devices available on the market place. We use the FloTrac at our institution, which is the only device that does not depend on recalibration and requires merely an arterial line. PICCO must be recalibrated using the transpulmonary thermodilution technique and therefore requires both central venous admission and a femoral arterial catheter. PulsCO must be recalibrated every 8 hours and uses the lithium dilution technique to do so. Although most studies take demonstrated that the pulse contour analysis technique is accurate and reliable, there are some limitations. Because it relies on the shape of the arterial waveform, a dampened arterial line tracing, the presence of atherosclerosis, or any arrhythmias, including frequent premature ventricular contractions, can generate inaccurate information. Alterations in chest wall compliance or certain ventilator settings (eg, elevated positive stop-expiratory pressure level) can affect the accurateness of pulse contour analysis. This monitoring system has non been validated in spontaneously animate patients. Concluding, these devices tin exist costly and therefore might not available in settings in which resources are limited.

Optical-based assessment of tissue perfusion

Most-infrared spectroscopy is a transcutaneous monitoring system that acts as a surrogate for tissue metabolism. Displaying results every bit regional oxygen saturation, near-infrared spectroscopy technology relies on the emission of infrared light to millimeters deeper than the traditional pulse oximeter. This technique differentiates between oxygenated and deoxygenated moieties (not simply blood-red blood cells). The algorithm within the private nigh-infrared spectroscopy devices is able to find changes in deoxy/oxy components of the subdermal microcirculation and acts as a existent-fourth dimension sensor of oxygen delivery and consumption. Though rigorous study and evaluation of near-infrared spectroscopy currently is unavailable, there are numerous reports of near-infrared spectroscopy monitoring systems foretelling astute decompensation events, almost-infrared spectroscopy values responding to vigorous resuscitations (ie, code events) and fluid resuscitations, and cerebral near-infrared spectroscopy being a sensitive indicator of acute brain attacks (strokes). However, this technology remains unproved versus gold-standard measurements.

Additional Readings

• »

  Busse L, Davison D, Junker C, Chawla LS. Hemodynamic monitoring in the disquisitional care surround. Adv Chronic Kidney Dis. 2013;xx(one):21-29.

• »

  Carcillo J, Davis A, Zaritsky A. Role of early fluid resuscitation in pediatric septic shock. JAMA. 1991;266(9):1242-1245.

• »

  Davison D, Junker C. Advances in critical care for the nephrologist: hemodynamic monitoring and volume management. Clin J Am Soc Nephrol. 2008;iii(ii):554-561.

• »

  Harvey Yard, Parker M. Fluid resuscitation targets, how do we get there? McMaster University Med J. 2009;2(9):39-41.

• »

  Jones AE, Shapiro NI, Trzeciak S, Arnold RC, Claremont HA, Kline JA. Lactate clearance vs. central venous oxygen saturation as goals of early sepsis therapy. JAMA. 2010;303(viii):739-746.

• »

  Lin SM, Huang CD, Lin HC, Liu CY, Wang CH, Kuo HP. A modified goal-directed protocol improves clinical outcomes in intensive care unit patients with septic daze: a randomized controlled trial. Shock. 2006;26(half dozen):551-557.

• »

  Marik PE, Baram K. Noninvasive hemodynamic monitoring in the intensive intendance units. Crit Care Clin. 2007;23(three):383-400.

• »

  McGee WT. A unproblematic physiologic algorithm for managing hemodynamics using stroke volume and stroke volume variation: physiologic optimization programme. J Intensive Care Med. 2009;24(6):352-360.

• »

  Perkin R, Anas North. Pulmonary artery catheters. Pediatr Crit Care Med. 2011;12(4 suppl):S12-S20.

• »

  Pinsky MR. Hemodynamic evaluation and monitoring in the ICU. Chest. 2007;132(6):2020-2029.

• »

  Price JF. Unique aspects of centre failure in the neonate. In: Shaddy R, ed. Heart Failure in Congenital Heart Affliction. 2nd ed. Philadelphia, PA: Springer Publishing; 2011.

• »

  Rivers E, Nguyen B, Havstad S, et al. Early goal-directed therapy in the treatment of sepsis and septic shock. Due north Engl J Med. 2001;345(19):1368-1377.

• »

  Scheeren TW, Schober P, Schwarte LA. Monitoring tissue oxygenation by well-nigh infrared spectroscopy (NIRS): background and current applications. J Clin Monit Comput. 2012;26(4):279-287.

Dangers of Fluid Resuscitation

As emphasized, early targeted fluid resuscitation to optimize tissue perfusion is the key to managing patients who are hemodynamically unstable. However, continued book resuscitation across what will ameliorate hemodynamics has detrimental effects. Increasing testify is demonstrating that a positive fluid balance is associated with worse outcomes. Single-heart data initially suggested that increased fluid overload percentage at the time of RRT initiation was associated with higher bloodshed in 2001. Since that time, data from more xiii separate centers in the Prospective Pediatric Continuous Renal Replacement Therapy (ppCRRT) Registry comprising 300 patients continues to indicate that a high fluid overload percentage is associated with worsened outcomes (higher mortality and longer duration of mechanical ventilation). Notation that the calculation for fluid overload percentage (FO%) is: FO% = (cumulative fluid in− cumulative fluid out)/weight (kg). Information from adults have paralleled this finding. A summary of the organ-specific consequences of overzealous fluid therapy is next.

Vasculature

Mediated by atrial natriuretic peptide release, excess fluid can lead to deposition of the glycocalyx barrier, ultimately increasing vascular permeability and promoting tissue edema. A viscious cycle of repeated boluses to maintain intravascular volume may ensue, which further contributes to the underlying pathophysiology.

Cardiac

Increased ventricular wall stretch, functional mitral and tricuspid insufficiency, resultant pulmonary hypertension, and exacerbation of diastolic dysfunction are all consequences of fluid aggregating.

Lungs

The consequence of fluid overload is most apparent in the lungs, in which pulmonary congestion causes increased workload and reduced compliance. The FACTT (Fluids and Catheters Treatment Trial) demonstrated that patients who received a restricted fluid regimen compared to a liberal regimen spent less fourth dimension on the ventilator and less time in the ICU. Similar findings were seen in an observational report of brain-dead organ donors in which a restricted fluid strategy resulted in an increase in number of lung procurements. The fluid restriction did not negatively affect kidney transplant function. In a single-center study of 80 mechanically ventilated children, fluid overload began to be correlated positively and independent with worsening oxygenation alphabetize at fifteen% relative volume aggregating.

Kidneys

As an encapsulated organ, the kidney has limits of expansion when edematous. On a mechanistic level, an increase in kidney venous pressure due to fluid overload decreases kidney arterial perfusion, increases interstitial force per unit area, and stimulates the renin-angiotensin arrangement, which worsens fluid accumulation. There are convincing data to show that volume overload at the time of dialysis initiation is associated with heightened mortality and decreases the likelihood of recovering kidney office. Moreover, no randomized controlled trials have demonstrated that a positive fluid residue prevents kidney injury during astute illness, whereas a v%-10% increase in h2o weight is associated with worsening organ function in patients with AKI.

Gastrointestinal/Abdominal Compartment

Postoperative ileus and malabsorption are prolonged as a consequence of fluid overload. A restricted fluid strategy has been shown to be associated with decreased incidences of complications after colorectal surgery, including anastomotic leaks, pulmonary edema, wound infection, and AKI. Intra-intestinal hypertension and intestinal compartment syndrome are major consequences of imprudent resuscitation. Intra-intestinal hypertension causes decreased venous render, decreased ventilator compliance, reduced renal blood menstruum, and subsequent evolution of shock and AKI.

Tissue Edema

Once thought of as simply a cosmetic concern, tissue edema at present is linked to impaired oxygen diffusion, obstruction of capillary blood flow and lymphatic drainage, poor wound healing, and the development of pressure level ulcers.

Immune System

The innate immune response, particularly to sepsis, may be abnormal in fluid overload states. Responses of humoral cytokines such every bit TNF-α, IL-four, IL-6, IL-10, and monocyte chemotactic poly peptide i reportedly have been altered in animal models of sepsis with fluid overload. Additionally, response of the Toll-like receptor family to pathogen-associated molecular patterns may be hampered in fluid overload states.

Fluid is a drug and should be treated as ane. Given the body of evidence reviewed, we suggest that intravenous fluid be viewed every bit a prescribed medication with indications, contraindications, and side effects. The correct "dose" is specific to each private based on his or her physiologic needs and can change dramatically inside hours of illness presentation. Recognizing and maintaining adequate oxygen delivery with fluid administration early in the grade of illness will better outcomes. Yet, when a patient is volume replete, we advise a strategy of fluid restriction and diuresis to foreclose or manage volume overload. Likewise oftentimes, fluid direction is left to the discretion of an inexperienced physician who indiscriminately gives a fluid bolus to the hypotensive or oliguric patient. Based on dynamic parameters and hemodynamic monitoring, this patient may benefit from other interventions, such every bit pressors, inotropes, or diuresis. Effigy 6 provides a schematic algorithm that can help the bedside clinician in ensuring organ perfusion while avoiding volume overload.

Additional Readings

• »

  Arikan AA, Zappitelli M, Goldstein SL, Naipaul A, Jefferson LS, Loftis LL. Fluid overload is associated with impaired oxygenation and morbidity in critically ill children*. Pediatr Crit Intendance Med. 2012;13(3):253-258.

• »

  Bouchard J, Soroko SB, Chertow GM, et al. Fluid accumulation, survival and recovery of kidney function in critically sick patients with acute kidney injury. Kidney Int. 2009;76(4):422-427.

• »

  Boyd JH, Forbes J, Nakada T, Walley KR, Russell JA. Fluid resuscitation in septic shock: a positive fluid balance and elevated cardinal venous pressure are associated with increased mortality. Crit Care Med. 2011;39(2):259-265.

• »

  Goldstein SL. Advances in renal replacement therapy in children. Semin Nephrol. 2011;24(2):187-191.

• »

  Miñambres E, Rodrigo E, Ballesteros MA, Llorca J, Ruiz JC, Fernandez-Fresnedo G. Impact of restrictive fluid balance focused to increase lung procurement on renal function after kidney transplantation. Nephrol Punch Transplant. 2010;25(7):2352-2356.

• »

  Payen D, de Pont AC, Sakr Y, et al. A positive fluid balance is associated with a worse outcome in patients with acute renal failure. Crit Intendance. 2008;12(iii):R74.

• »

  Sutherland SM, Zappitelli One thousand, Alexander SR, et al. Fluid overload and mortality in children receiving continuous renal replacement therapy: the Prospective Pediatric Continuous Renal Replacement Therapy Registry. Am J Kidney Dis. 2010;55(2):316-325.

• »

  Vincent JL, Sakr Y, Sprung CL, et al. Sepsis in European intensive care units: results of the Soap Study. Crit Care Med. 2006;34(2):344-353.

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  Weidemann HP, Wheeler AP, Bernard GR, et al. Comparison of two fluid-management strategies in astute lung injury. Due north Engl J Med. 2006;354(24):2564-2575.

Have Home Points

Without evidenced-based guidelines to straight volume management, information technology is essential to empathise the underlying physiology, including vascular integrity and fluid shifts, in order to make a rational choice of the type, amount, and mechanism by which to monitor fluid therapy.

In today's wellness care environment, in which toll savings and patient safe are paramount, focusing on the overall cost and side furnishings of each individual fluid should be the main determinant of which fluid to cull. Nosotros recommend using balanced crystalloid solutions for resuscitative purposes, with the addition of albumin in select patients.

Securing adequate intravascular volume to optimize the delivery of oxygen to tissues is the master goal of resuscitation. Using surrogates of commitment and extraction, including Svo ₂, Scvo ₂, and lactate levels, tin assistance place patients with global oxygen debt.

The chief determinant of oxygen commitment to organs is cardiac output. Static measurements, including fundamental venous pressure and pulmonary artery occlusion pressure, are not valid markers of intravascular volume status. Dynamic monitors better assess whether volume volition better cardiac output and the delivery of oxygen to tissues.

Monitoring devices that brandish dynamic variables and cardiac output in a continuous fashion tin can exist instrumental to ensuring that bolus administration is both timely and appropriate.

Continued volume resuscitation beyond what volition improve hemodynamics has detrimental furnishings. Fluid is a drug and is prescribed, dosed, and delivered similar all other medications. Overdose is a possibility and as well often is a reality. When hemodynamic goals have been met, one should consider a strategy of fluid restriction or diuresis.

Resuscitation of children must take into consideration the unique features of children's physiology, particularly in neonatal and infant patients who have less myocardial and pulmonary reserve in addition to young capabilities of treatment salt and water.

Acknowledgements

Support: None.

Financial Disclosure: The authors declare that they accept no relevant fiscal interests.

Article Info

Publication History

Published online: December 13, 2013

Accepted: Oct 15, 2013

Received: July 9, 2013

Identification

DOI: https://doi.org/x.1053/j.ajkd.2013.10.044

Copyright

© 2014 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

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Source: https://www.ajkd.org/article/S0272-6386%2813%2901427-3/abstract

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