A 5-year-old girl with acute leukemia presents with fever, tachycardia, and signs of shock (capillary refill > 3 seconds, weak pulses). Regarding the pathophysiology and management of pediatric hypovolemic shock, all of the following are correct EXCEPT:

Explanation

## Pediatric Hypovolemic Shock: Pathophysiology and Management ### Phases of Hypovolemic Shock **Key Point:** Pediatric hypovolemic shock progresses through compensated and decompensated phases, each with distinct clinical and metabolic features. ### Compensated Shock **High-Yield:** In compensated shock: - **Sympathetic activation** → ↑ heart rate (tachycardia), ↑ contractility, ↑ peripheral vasoconstriction - **Blood pressure maintained** despite reduced circulating volume - Skin: cool, pale, mottled; capillary refill > 2 seconds - Urine output: reduced but present - Mental status: may be altered (irritability, confusion) - **Lactate begins to rise** (early tissue hypoperfusion) ### Decompensated Shock **Clinical Pearl:** Decompensated shock represents **failure of compensatory mechanisms**: - **Hypotension** (late, ominous sign in children) - **Bradycardia** (due to severe hypoxia, acidosis, or myocardial depression) - Severe **metabolic acidosis** (pH < 7.2, high lactate > 4 mmol/L) - Weak or absent pulses - Altered mental status → unresponsiveness - **This phase is reversible only with aggressive intervention** ### Fluid Resuscitation: First-Line Agent **High-Yield:** Initial fluid for hypovolemic shock depends on **cause and acuity**: | Scenario | First-Line Fluid | Dose | Rationale | |----------|------------------|------|----------| | **Hemorrhagic shock (trauma, GI bleed)** | **Isotonic crystalloid (0.9% NaCl or RL)** | **20 mL/kg bolus over 15–30 min** | Rapid volume expansion; crystalloid is initial choice | | **Hemorrhagic shock (unresponsive to 2 crystalloid boluses)** | **Packed RBC (pRBC)** | **10 mL/kg** | Restores oxygen-carrying capacity; given AFTER crystalloid failure | | **Non-hemorrhagic hypovolemic shock (diarrhea, burns)** | **Isotonic crystalloid** | **20 mL/kg bolus** | First-line for all non-hemorrhagic causes | **Warning:** Packed RBCs are **NOT first-line** for initial hypovolemic shock resuscitation. Isotonic crystalloid is always the first fluid bolus. pRBC is reserved for: - Hemorrhagic shock unresponsive to 2 crystalloid boluses - Ongoing significant hemorrhage - Hemoglobin < 7 g/dL in shock state ### Concurrent Management of Ongoing Losses **Key Point:** Hypovolemic shock resuscitation must address **both**: 1. **Bolus resuscitation** (20 mL/kg crystalloid ± pRBC) 2. **Ongoing loss replacement** (maintenance fluids + deficit correction + ongoing losses) **Clinical Pearl:** Failure to replace ongoing losses (e.g., continued diarrhea, active hemorrhage, burn evaporation) will result in recurrent shock despite initial resuscitation. ### Reassessment After Resuscitation **High-Yield:** After each bolus: - Capillary refill (goal < 2 sec) - Heart rate (should normalize) - Blood pressure (age-appropriate) - Urine output (goal > 1 mL/kg/hr infants; > 0.5 mL/kg/hr older children) - Lactate clearance (goal < 2 mmol/L) - Mental status If shock persists after 2 crystalloid boluses (40 mL/kg), consider: - Transfusion (if hemorrhagic) - Inotropic support (dopamine, epinephrine) - Vasopressors (norepinephrine if hypotensive) [cite:Pediatric Advanced Life Support (PALS) 2020; American College of Surgeons ATLS 10e] ### Why Option 3 is Incorrect Packed RBCs (10 mL/kg) are **NOT first-line** for initial hypovolemic shock. Isotonic crystalloid (0.9% NaCl or Ringer's lactate) 20 mL/kg is the first fluid bolus in all cases of hypovolemic shock. pRBC is given only after crystalloid boluses fail or if hemorrhage is ongoing and hemoglobin is critically low.