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PE24.{3,12-14} | Shock Emergency — SDL Guide (Part 3)
Interpretation: Monitoring Response to Resuscitation
Response to fluid resuscitation must be assessed systematically after every bolus, using the same clinical parameters used to diagnose shock. The goal is not simply to give fluids but to restore adequate tissue perfusion, which requires serial re-evaluation. A child who fails to improve after 60 mL/kg total crystalloid (three 20 mL/kg boluses) has fluid-refractory shock and requires vasopressors and intensive care support — continuing to give more fluid without inotropic support will not improve perfusion and risks fluid overload. Understanding the expected trajectory of improvement after each bolus is as important as knowing how to give the bolus: a child in hypovolaemic shock should show measurable improvement in heart rate and CRT within 15 minutes of a 20 mL/kg bolus; failure to improve at all by 15 minutes after the first bolus, or improvement followed by rapid relapse, suggests ongoing losses or a more complex shock physiology (e.g., septic shock with vasodilation requiring vasopressors, or obstructive shock where fluid is irrelevant to the cause).
Clinical endpoints of successful resuscitation (all should trend toward normal after each bolus):
• HR declining toward the upper limit of normal for age (not necessarily normal — some residual tachycardia from fever is expected)
• CRT shortening toward <2 seconds
• BP rising toward normal range for age
• Mental status improving — child becoming more alert, interactive, able to drink
• Peripheral pulses becoming more palpable
• Urine output increasing toward ≥1 mL/kg/h
• Skin warming and mottling resolving
Indicators of fluid-refractory shock (requiring escalation):
• No improvement in HR, CRT, or mental status after 40–60 mL/kg crystalloid
• Persistent hypotension despite adequate fluid volume
• Development of new pulmonary crepitations or worsening respiratory distress (fluid overload)
• Declining or absent urine output
• Bradycardia developing during resuscitation (signifies failing cardiac reserve)
Vasopressor selection when fluid resuscitation is insufficient:
• Dopamine (3–10 mcg/kg/min): increases HR and contractility (beta-1 at lower doses); vasoconstriction at higher doses (alpha-1); commonly first-line in septic shock in resource-limited settings
• Noradrenaline (0.05–2 mcg/kg/min): predominantly alpha-1 vasoconstriction; preferred for warm distributive septic shock (hypotensive with high CO)
• Adrenaline (0.05–1 mcg/kg/min): combined alpha and beta agonist; used when both vasopressor effect and inotropic support are needed (cold septic shock, anaphylactic shock unresponsive to IM adrenaline)
• Dobutamine (3–15 mcg/kg/min): primarily inotropic (beta-1); used for cardiogenic shock with low contractility; avoid in hypovolaemic shock (causes vasodilation)
All vasopressors should be delivered via a central or IO line as a continuous infusion — extravasation into peripheral tissue causes severe skin necrosis.
Applied Practice: Managing Shock in a Simulated Setting
Integrating the recognition, access, and fluid resuscitation skills into a coherent clinical response requires simulation practice under observation. The simulation scenario below is designed for a two-person team — one student performing the primary assessment and a second preparing access and fluids. The scenario can be completed in 10–15 minutes with a paediatric manikin, a simulated IV/IO kit, and a fluid bag. The most common failure mode in simulation is sequential rather than parallel action — students assess the child fully, then call for help, then attempt IV, then calculate the fluid, then give it. In reality, all of these steps happen simultaneously or in rapid succession with team members working in parallel. Practise calling for help at the moment you identify shock, not after you have completed your full assessment. Practise calculating the fluid volume aloud as your partner prepares the line. These parallel habits are what distinguish experienced emergency providers from students who know the content but are slow to act under pressure.
Scenario: A 15 kg, 3-year-old child is found with altered mental status following 24 hours of fever, vomiting, and not feeding. HR 172/min, RR 44/min, BP 78/50 mmHg (below 5th percentile for age = decompensated shock), CRT 5 seconds, skin mottled, cool peripheries, AVPU = P (responds to pain). Two people are available.
Performance checklist:
| Step | Expected action |
|---|---|
| 1 | Call for help; assign one person to airway/assessment, one to access/fluids |
| 2 | Call PICU/senior — 'paediatric septic shock, decompensated, needs vasopressors' |
| 3 | Apply oxygen (NRM 15 L/min) |
| 4 | Attempt peripheral IV × 1 attempt; if not within 90 s → IO at proximal tibia |
| 5 | Draw blood (blood culture, glucose, FBC, electrolytes) before first bolus |
| 6 | Calculate fluid bolus: 20 mL/kg = 20 × 15 = 300 mL isotonic crystalloid |
| 7 | Run 300 mL 0.9% NS/Ringer's via syringe/gravity push over 10–15 min |
| 8 | Reassess at 15 min: HR, CRT, BP, mental status, breath sounds |
| 9 | Check blood glucose — treat hypoglycaemia (glucose <2.6 mmol/L) promptly |
| 10 | Give broad-spectrum antibiotics (IV ceftriaxone 50–100 mg/kg if bacterial sepsis suspected) |
| 11 | If no improvement after first bolus: repeat 20 mL/kg bolus × 2 (total 60 mL/kg max) |
| 12 | If no improvement after 60 mL/kg: start dopamine or noradrenaline infusion |
Self-monitoring during simulation:
• Did you verbally calculate the fluid volume aloud and confirm with your partner?
• Did you reassess after EVERY bolus before giving the next?
• Did you check blood glucose — hypoglycaemia is a life-threatening concurrent problem in septic shock?
• Was your IO insertion confident and correctly landmarked?
Self-Assessment: Shock Emergency
The following self-assessment questions span the full scope of this module — from recognising the phase of shock, to calculating fluid volumes, to differentiating shock types by their distinguishing features. Work through each question before reviewing the answers. The volume-calculation questions require you to show your arithmetic: dose × weight = volume. This practice prevents errors in clinical settings. The shock-type differentiation question (question 4) is high-yield for clinical reasoning and MBBS short-answer questions — a child with warm, bounding pulses and fever is in a different category to a child with cold, clammy skin and hypovolaemia, even though both are in shock. Remember that the neonatal exception (10 mL/kg) and the DKA exception (10 mL/kg) will be specifically tested because they represent cases where the default 20 mL/kg rule could cause harm; committing the exception list to memory is as important as the default rule. Question 5 requires you to describe the IO landmark in words precise enough that a colleague could perform the procedure from your description — this is the standard set by clinical skill assessments at the MBBS level.
- A 5-year-old child (18 kg) has HR 178/min, CRT 3.5 s, BP 95/60 mmHg. Is this child in compensated or decompensated shock? What is your first fluid bolus (volume and type)?
- A 2-month-old infant (4.5 kg) is in shock from sepsis. What is the correct fluid bolus volume? Why is it different from an older child?
- What is the maximum total crystalloid bolus volume (in mL/kg) before you should escalate to vasopressors?
- A child in shock has warm, flushed skin, bounding peripheral pulses, and a high fever. What type of shock is most likely? Contrast this with the findings expected in hypovolaemic shock.
- At which landmark do you insert an IO needle in a child? Describe the two confirmatory signs of correct IO placement.
- Why should you NOT use 5% dextrose as a resuscitation fluid in shock?
Answers:
1. Compensated shock (BP normal for a 5-year-old: lower limit = 70+2×5 = 80 mmHg; 95 is normal; but tachycardia and prolonged CRT indicate poor perfusion). First bolus: 20 mL/kg × 18 = 360 mL isotonic crystalloid (0.9% NS or Ringer's lactate) over 5-15 min.
2. Neonates and young infants: 10 mL/kg = 10 × 4.5 = 45 mL; neonatal myocardium has limited reserve and cannot tolerate rapid large-volume expansion — risk of intraventricular haemorrhage and NEC.
3. 60 mL/kg total (three boluses of 20 mL/kg), reassessing after each.
4. Warm distributive (septic) shock — early 'warm phase': vasodilation + high CO. Hypovolaemic shock presents with cold peripheries, poor pulse volume, pallor/mottling, collapsed veins, and history of fluid losses.
5. 1–2 cm distal and medial to the tibial tuberosity on the anteromedial flat surface of the proximal tibia. Confirmatory signs: needle stands unsupported, marrow aspirate obtained (or 5 mL saline flushes freely without subcutaneous swelling).
6. 5% dextrose is hypotonic — distributes into intracellular space rather than remaining in the intravascular compartment; does not restore circulating volume effectively and can worsen hyponatraemia and cerebral oedema.