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Please wait while the page loadsNursing Process in Action · Children's Nursing
Year 2Why shock is about perfusion, not blood pressure, how compensated shock tips into decompensated, the seven D NACHOS types, and what inotropes actually do when fluids are not enough.
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Student note
Perfusion means blood actually reaching tissues. An inotrope changes how strongly the heart contracts. A chronotrope changes heart rate. A vasopressor narrows blood vessels to raise blood pressure. CRT is capillary refill time. D NACHOS is a mnemonic for the seven shock types: Distributive, Neurogenic, Anaphylactic, Cardiogenic, Hypovolaemic, Obstructive, Septic.
Core definition
Shock = inadequate tissue perfusion for metabolic demand, not simply low blood pressure.
BP formula
Lowest acceptable systolic BP = age in years × 2 + 70. A minimum threshold, not proof of good perfusion.
Hypotension rule
Hypotension is a late sign in children – by the time it appears, compensation has already failed.
Treatment rule
Treatment depends on the type: fluids, adrenaline, antibiotics, inotropes, or relieving an obstruction.
Why is shock about perfusion, not just blood pressure?
The core problem
Supply vs demand
What oxygen delivery depends on
Why it matters
Clinical pearl
Shock is not "low blood pressure." It is inadequate tissue perfusion – and in children, blood pressure can stay normal for a surprisingly long time while the child is already compensating hard.
What actually changes as shock progresses through each stage?
Compensated
Decompensated
Irreversible
Why hypotension is late
Red flags
Clinical pearl
Do not wait for low blood pressure before worrying. By the time a child is hypotensive, compensation has already failed – that is decompensated shock, not an early warning.
Why does each individual sign of shock actually happen?
Tachycardia
Delayed CRT & cool skin
Reduced urine & altered mental state
Warm shock vs cold shock
Clinical pearl
Cold shock and warm shock look almost opposite at the bedside, but both mean the same underlying problem: blood is not reaching tissues effectively. Do not assume warm, flushed skin rules shock out.
Why does knowing the shock type change what you do next?
Distributive & neurogenic
Anaphylactic & septic
Cardiogenic & hypovolaemic
Obstructive
Clinical pearl
D NACHOS is not just a memory aid – it stops you treating every shock the same way. Hypovolaemic needs volume. Cardiogenic needs caution with fluids. Anaphylactic needs adrenaline. Septic needs antibiotics and support. Obstructive needs the obstruction physically relieved.
What do you actually check, and in what order, in a shocked child?
A & B
C & D
E & the management sequence
Initial treatments
Red flags
Clinical pearl
Shock management is dynamic, not a one-off checklist. After every intervention – oxygen, fluids, antibiotics, an inotrope change – repeat A–E and compare the trend. Improving HR, warmer skin, stronger pulses, more alert, and rising urine output are the signs you actually want to see.
When fluids are not enough, what do these drugs actually do?
The vocabulary
Adrenaline & noradrenaline
Milrinone
Safe administration
Red flags
Clinical pearl
If several infusions are changed together, you cannot tell which one caused an improvement or a problem. Titrating one drug at a time is what makes the response interpretable – and safe.
| Child's age | Formula | Lowest acceptable systolic BP |
|---|---|---|
| 1 year | 1 × 2 + 70 | 72 mmHg |
| 3 years | 3 × 2 + 70 | 76 mmHg |
| 5 years | 5 × 2 + 70 | 80 mmHg |
| 8 years | 8 × 2 + 70 | 86 mmHg |
| 10 years | 10 × 2 + 70 | 90 mmHg |
Exam tip
This formula gives the lowest systolic pressure expected to maintain organ perfusion — it is a minimum safety threshold, not proof a child is well perfused. A child can be compensating and deteriorating well before they become hypotensive.
| Type | Core problem | Typical clue |
|---|---|---|
| Distributive | Excessive vasodilation, poor blood distribution | Includes septic, anaphylactic, neurogenic |
| Neurogenic | Loss of nervous system control of HR/BP/temperature | Follows CNS, brain, or spinal cord injury |
| Anaphylactic | Histamine release causing vasodilation, leak, airway swelling | Rash, swelling, wheeze/stridor after exposure |
| Cardiogenic | The heart pump itself fails | Poor feeding, hepatomegaly, crackles – caution with fluids |
| Hypovolaemic | Not enough circulating volume | Bleeding, vomiting, diarrhoea, burns, dehydration |
| Obstructive | Mechanical block to flow into/out of the heart | Sudden deterioration, tamponade/pneumothorax clues |
| Septic | Infection-triggered inflammatory cascade | Fever or hypothermia, altered behaviour, poor perfusion |
| Drug | Main action | Dose range (from lecture slides) | Watch for |
|---|---|---|---|
| Adrenaline | Beta effects (↑HR, contractility) at low dose; alpha (vasoconstriction) at higher dose | 0.01–1.5 mcg/kg/min | Tachyarrhythmias, ↑myocardial O₂ demand, ↓renal blood flow |
| Noradrenaline | Alpha and beta-1 effects; potent vasoconstrictor | 0.02–1 mcg/kg/min | Excess vasoconstriction, perfusion, rhythm |
| Milrinone | Supports cardiac function; causes vasodilation | 0.3–1 mcg/kg/min | Hypotension (from vasodilation) |
Student note
These figures are transcribed from lecture slides for revision purposes. Always check your local trust protocol and the current BNF for Children before any real administration — this page does not replace clinical teaching or prescribing guidance.
| Step | What is happening |
|---|---|
| Infection | A pathogen enters the body or bloodstream. |
| Cytokine release | Immune chemicals call more infection-fighting cells – helpful locally, dangerous if excessive body-wide. |
| Vasodilation | Blood vessels relax and widen; pressure falls. |
| Capillary leak | Fluid moves out of the bloodstream into tissues; effective circulating volume falls. |
| Poor perfusion | Organs receive less oxygenated blood; lactate may rise. |
| Organ dysfunction | Brain, kidneys, lungs, circulation, or clotting become affected – this is what makes sepsis life-threatening. |
Clinical pearl
Sepsis is not just “a bad infection.” It is what happens when the body's own response to infection becomes harmful: pathogen enters → immune response becomes excessive → vessels dilate and leak → perfusion falls → organs become hypoxic and dysfunctional. Septic shock is a type of distributive shock.
| Case | Presentation | Reasoning | Response |
|---|---|---|---|
| Annabel, age 3 | Sudden fever, given diclofenac, rash 30 minutes later. HR 160, BP 78/40, SpO₂ 68%. | Rash after drug exposure + hypoxia + hypotension → anaphylactic shock. | 15 minutes after IM adrenaline: HR 142, BP 106/52, SpO₂ 92%. |
| Jack, age 4 | 5-day vomiting history, 2-day fever >39.5°C, represented drowsy and confused. HR 170, BP 90/50, SpO₂ 88%, RR 30. | Fever + vomiting (volume loss) + tachycardia + drowsiness → likely septic/dehydration picture. | Priorities: repeat A–E, oxygen, sepsis/shock pathway, bloods/cultures/lactate, antibiotics, escalate early. |
D NACHOS
Distributive, Neurogenic, Anaphylactic, Cardiogenic, Hypovolaemic, Obstructive, Septic
3 stages
Compensated (normal BP) → decompensated (hypotensive) → irreversible (organ failure)
Warm vs cold
Cold = vessels constricted (mottled, delayed CRT). Warm = vessels too relaxed (flushed, bounding)
One at a time
Titrate one inotrope change at a time so the response stays interpretable
Sources & References
Resuscitation Council UK (2021) — 2021 Resuscitation Guidelines – paediatric shock and sepsis recognitionNICE (2016, updated 2024) — Sepsis: recognition, diagnosis and early management (NG51)NICE (2011, updated 2019) — Anaphylaxis: assessment and referral after emergency treatment (CG134)BNF for Children — Current dosing guidance – always verify against the live BNFc before clinical useAlso practice with