What is the appropriate choice of intravenous (IV) fluid for adult patients with varying medical conditions and situations, such as trauma, surgery, severe dehydration, significant blood loss, heart failure, or liver disease?

IV Fluid Selection for Adult Patients in Different Clinical Situations

Use balanced crystalloids (Ringer's Lactate or Plasmalyte) as first-line therapy for most critically ill patients, avoiding 0.9% saline for large volume resuscitation and reserving colloids only for highly specific indications.

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General Principles: Crystalloids vs. Colloids

Crystalloids Are Preferred Over Colloids in Most Situations

• Crystalloids should be used rather than colloids for volume expansion in critically ill patients in general, patients with sepsis, acute respiratory failure, and perioperative/bleeding risk patients 1
• Colloid solutions (hydroxyethyl starches, gelatins) show no mortality benefit compared to crystalloids and carry increased risks of renal failure and hemostasis disorders 2
• In hemorrhagic shock specifically, colloids are not recommended compared to crystalloids for reducing mortality or renal replacement therapy requirements 2
• Albumin shows no benefit over crystalloids in trauma patients without traumatic brain injury and is not recommended for hemorrhagic shock 2

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Balanced Crystalloids vs. 0.9% Saline

Balanced Crystalloids Are Superior to Normal Saline

• In critically ill patients, sepsis, and those with kidney injury, balanced crystalloids should be used rather than 0.9% saline 1
• Balanced crystalloids reduce 30-day mortality (OR 0.84,95% CI 0.74-0.95) and major adverse kidney events compared to normal saline, particularly in sepsis patients 3
• The SMART trial of 15,802 ICU patients demonstrated lower mortality and reduced need for renal replacement therapy with balanced crystalloids 3

Why 0.9% Saline Is Harmful in Large Volumes

• Normal saline contains supraphysiologic chloride concentration (154 mmol/L) that causes hyperchloremic metabolic acidosis, leading to renal vasoconstriction and acute kidney injury 3
• Large volumes (>5000 mL) of chloride-rich solutions are associated with increased mortality in observational studies 3
• If normal saline must be used, limit to maximum 1-1.5 L to minimize chloride load 3

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Situation-Specific Recommendations

Hemorrhagic Shock and Trauma

• Use balanced crystalloids as first-line fluid therapy rather than 0.9% NaCl to reduce mortality and adverse renal events 2
• Avoid colloids entirely due to lack of mortality benefit, increased renal failure risk, and hemostasis disorders with increased transfusion requirements 2
• High volumes are often required (regularly exceeding 5000-10,000 mL in first 24 hours), making balanced solutions critical to avoid hyperchloremic acidosis 2

Sepsis and Septic Shock

• Balanced crystalloids are strongly recommended as first-line fluid therapy 3
• Benefits are most pronounced when initiated in the emergency department rather than delayed until ICU admission 3
• Crystalloids should be used rather than albumin (moderate certainty of evidence) 1

Major Surgery and Perioperative Period

• Use balanced crystalloids for resuscitation and intravascular volume maintenance 3
• Registry studies show fewer complications with balanced crystalloids compared to 0.9% saline, with dose-response relationship between saline volume and adverse outcomes 3
• Limit 0.9% saline use, especially in high-risk patients with existing acidosis or hyperchloremia 3

Traumatic Brain Injury (TBI)

• Use isotonic saline rather than albumin 1
• Use isotonic saline rather than balanced crystalloids 1
• Avoid hypotonic balanced solutions to prevent cerebral edema 3

Cirrhosis and Liver Disease

• Albumin should be used rather than crystalloids in patients with cirrhosis 1
• In acute liver failure, albumin serves dual purpose of supporting colloid osmotic pressure and binding excess plasma bilirubin 4
• Removal of ascitic fluid may cause hypovolemic shock requiring albumin infusion to support blood volume 4

Burns (Beyond 24 Hours)

• During first 24 hours, large volumes of crystalloids restore depleted extracellular fluid volume 4
• Beyond 24 hours, albumin 25% can be used to maintain plasma colloid osmotic pressure 4

Hypoproteinemia with Fluid Overload

• In Adult Respiratory Distress Syndrome (ARDS) with hypoproteinemia and fluid volume overload, albumin 25% together with a diuretic may play a role 4
• During major surgery or sepsis, patients can lose over half their circulating albumin; albumin 25% treatment may be valuable 4

Cardiopulmonary Bypass

• Preoperative blood dilution using albumin and crystalloid is safe and well-tolerated 4
• Common practice: adjust albumin and crystalloid pump prime to achieve hematocrit 20% and plasma albumin 2.5 g/100 mL 4

Kidney Stones

• Administer balanced crystalloid solutions (Ringer's Lactate or Plasmalyte) at maintenance rates 5
• Isotonic crystalloids are preferred over colloids in patients at risk for acute kidney injury 5
• Avoid synthetic colloids due to renal dysfunction risk 5

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Clinical Algorithm for IV Fluid Selection

Step 1: Identify Clinical Scenario

• Hemorrhagic shock/trauma → Balanced crystalloids
• Sepsis/septic shock → Balanced crystalloids
• Major surgery/perioperative → Balanced crystalloids
• TBI → Isotonic saline (0.9% NaCl)
• Cirrhosis/liver failure → Albumin
• Burns >24 hours → Albumin 25%
• Hypoproteinemia with fluid overload → Albumin 25% + diuretic

Step 2: Avoid These Pitfalls

• Never use synthetic colloids (hydroxyethyl starch, gelatin) due to renal failure risk 2, 5
• Never use large volumes (>1-1.5 L) of 0.9% saline except in TBI 3
• Never use hypotonic solutions in TBI patients 3
• Never use albumin in chronic nephrosis (promptly excreted with no benefit) 4

Step 3: Monitor Response

• Track urine output, vital signs, and electrolytes 5
• Watch for hyperchloremia if using normal saline 3
• Observe for circulatory overload, especially with albumin 25% (hyperoncotic, expands plasma volume 3-4 times administered volume) 4
• Discontinue nephrotoxins (NSAIDs, aminoglycosides) when administering fluids for kidney-related conditions 5

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Situations Where Albumin Is NOT Warranted

• Chronic nephrosis: Albumin is promptly excreted by kidneys with no relief of edema or effect on renal lesion 4
• Chronic cirrhosis, malabsorption, protein-losing enteropathies, malnutrition: Albumin infusion as protein nutrition source is not justified 4
• General volume resuscitation: No greater clinical benefit than crystalloids 6