Why should intravenous fluids not be given to a patient with chills and rigors in the absence of hypotension, tachycardia, dehydration, or other evidence of hypovolemia?

Why IV Fluids Should Not Be Given for Chills and Rigors Alone

Intravenous fluids should not be routinely administered to patients presenting with chills and rigors in the absence of hemodynamic instability, signs of shock, or evidence of hypovolemia, because these symptoms alone do not indicate fluid deficit and unnecessary fluid administration risks iatrogenic harm including pulmonary edema and fluid overload. 1, 2

Understanding Chills and Rigors as Clinical Signs

Chills and rigors are physiological responses to fever and infection, representing the body's thermoregulatory response rather than indicators of volume depletion. 2 These symptoms occur when:

• Fever triggers hypothalamic temperature set-point elevation, causing peripheral vasoconstriction and shivering to generate heat 2
• Cytokine release during infection (particularly IL-6 and TNF-alpha) produces systemic inflammatory responses that include rigors 1
• The patient maintains normal intravascular volume despite feeling subjectively unwell 2, 3

When IV Fluids ARE Indicated in Febrile Patients

IV fluid administration becomes appropriate only when specific objective criteria are met, not based on chills/rigors alone:

Hemodynamic Instability

• Hypotension with systolic BP <90 mmHg or MAP <65 mmHg requires immediate crystalloid bolus of 20 mL/kg (maximum 1,000 mL initially in adults) 1
• Tachycardia with evidence of poor perfusion (cool extremities, prolonged capillary refill >3 seconds, altered mental status) indicates tissue hypoperfusion requiring fluid resuscitation 1, 2

Laboratory Evidence of Tissue Hypoperfusion

• Lactate ≥4 mmol/L represents a medical emergency requiring immediate protocolized resuscitation with at least 30 mL/kg crystalloid within first 3 hours 1, 2, 4
• Lactate 2-4 mmol/L indicates potential tissue hypoperfusion warranting aggressive fluid resuscitation even with normal blood pressure 1, 4

Clinical Signs of Dehydration

• Oliguria (<0.5 mL/kg/hour) indicating inadequate renal perfusion 1, 2
• Dry mucous membranes, decreased skin turgor, sunken eyes suggesting true volume depletion 2, 3

The Harm of Unnecessary IV Fluids

Fluid Overload Complications

Excessive fluid administration causes significant morbidity and mortality, particularly in patients with:

• Pre-existing cardiac dysfunction: Rapid fluid boluses can precipitate acute pulmonary edema and cardiogenic shock 1, 5
• Renal impairment: Reduced ability to excrete excess fluid leads to volume overload 2, 5
• Elderly patients: Decreased cardiac reserve and impaired renal function increase vulnerability to fluid overload 2, 5

Evidence Against Routine Fluid Administration

• Pediatric studies show no benefit from routine fluid boluses in "severe febrile illness" without shock (median 76.2 vs 78.1 mL/kg, not significant) 1
• Guidelines explicitly recommend AGAINST routine bolus IV fluids for febrile patients not in shock (weak recommendation, low-quality evidence) 1
• Conservative fluid strategies associate with lower mortality in critically ill patients compared to liberal fluid administration 6

The Correct Clinical Approach

Initial Assessment Algorithm

Step 1: Assess for shock indicators 1, 2

• Measure blood pressure (target MAP ≥65 mmHg)
• Evaluate heart rate and perfusion (capillary refill, extremity temperature)
• Check mental status
• Measure urine output (target ≥0.5 mL/kg/hour)

Step 2: Obtain lactate measurement 1, 4

• Lactate ≥4 mmol/L → immediate resuscitation
• Lactate 2-4 mmol/L → aggressive monitoring and fluid consideration
• Lactate <2 mmol/L → no indication for IV fluids based on lactate alone

Step 3: Evaluate for true dehydration 2, 3

• History of inadequate oral intake
• Ongoing losses (vomiting, diarrhea)
• Physical examination findings of volume depletion

Management Based on Assessment

For chills/rigors WITHOUT hemodynamic compromise:

• Administer antipyretics (acetaminophen or NSAIDs) for symptomatic relief 2
• Encourage oral hydration with reduced osmolarity ORS or clear fluids 2, 3
• Initiate appropriate antibiotics if bacterial infection suspected 1
• Monitor vital signs and clinical status for development of shock 1, 2

For chills/rigors WITH hemodynamic compromise:

• Begin immediate crystalloid resuscitation (20 mL/kg bolus, maximum 1,000 mL initially) 1
• Reassess after each bolus for signs of fluid responsiveness or overload 1
• Consider early vasopressor support (norepinephrine) if hypotension persists after initial fluid bolus 1

Critical Pitfalls to Avoid

Common Errors in Clinical Practice

Do not reflexively administer IV fluids based solely on patient discomfort from chills/rigors without objective evidence of volume depletion 1, 2, 6

Do not use central venous pressure (CVP) to guide fluid administration, as it is completely unreliable for assessing volume status or fluid responsiveness 6

Do not delay vasopressor initiation in hypotensive patients while administering excessive fluid volumes—early norepinephrine after initial fluid bolus improves outcomes 1, 6

Do not ignore signs of fluid overload during resuscitation: increased jugular venous pressure, pulmonary crackles/rales, worsening oxygenation 1

Special Population Considerations

Elderly patients with cardiac history: Limit initial fluid bolus to 250-500 mL over 15 minutes with careful reassessment, as they rapidly develop pulmonary edema 1, 5

Patients with known heart failure: Clinical reassessment for pulmonary edema is mandatory after any fluid administration 1, 3

Pediatric patients: Use 10-20 mL/kg boluses (maximum 1,000 mL) with mandatory reassessment after each bolus 1

Monitoring Strategy When Fluids Are Given

When IV fluids are appropriately indicated, monitor for:

• Urine output trending toward ≥0.5 mL/kg/hour indicating restored renal perfusion 1, 2
• Lactate clearance of ≥10% every 2 hours during first 8 hours of resuscitation 1, 4
• MAP maintained ≥65 mmHg without excessive vasopressor requirements 1
• Signs of fluid overload: increased work of breathing, oxygen desaturation, pulmonary crackles 1