Chapter 21 review

Chapter 21-

🧠 1. SYSTEMS MAP β€” FOUNDATIONAL BLUEPRINT

A. PERFUSION PATHWAY (HEART ↔ TISSUES ↔ KIDNEYS)

  1. Basic flow
    RA β†’ RV β†’ Pulmonary artery β†’ Lungs β†’ Pulmonary veins β†’ LA β†’ LV β†’ Aorta β†’ Systemic arteries β†’ Capillaries β†’ Veins β†’ RA

  2. Cardiac output (CO)

  • CO = HR Γ— SV (4–8 L/min)

  • SV depends on:

    • Preload = volume in ventricles at end-diastole

    • Afterload = resistance the LV pumps against (SVR, BP, stenotic valves)

    • Contractility = squeeze strength

  1. Perfusion + kidneys

  • Adequate CO β†’ good renal perfusion β†’ normal UOP (β‰₯ 0.5 mL/kg/hr) β†’ stable Cr, BUN

  • ↓ CO β†’ ↓ renal perfusion β†’

    • ↓ UOP

    • ↑ Cr, ↑ BUN

    • RAAS activation β†’ vasoconstriction + Na/Hβ‚‚O retention β†’ ↑ preload β†’ can worsen HF

  1. Perfusion β†’ brain / skin

  • ↓ perfusion β†’ AMS, dizziness, syncope, cold/clammy skin, delayed cap refill, weak pulses, hypotension

  • Severe ↓ perfusion = shock.

B. ELECTRICAL CONDUCTION PATHWAY (CV)

  1. Normal pathway
    SA node β†’ internodal pathways β†’ AV node β†’ Bundle of His β†’ R/L bundle branches β†’ Purkinje fibers

  2. Phases of cardiac action potential (ventricular myocyte)
    (You don’t need every ion detail on NCLEX, but this is the logic):

  • Phase 0: Na⁺ in β†’ rapid depolarization β†’ QRS

  • Phase 1: early repolarization

  • Phase 2: Ca²⁺ in (plateau) β†’ contraction (systole)

  • Phase 3: K⁺ out β†’ repolarization β†’ T wave

  • Phase 4: resting membrane potential

  1. Electrolytes & electrical stability

  • K⁺:

    • ↑ K⁺ β†’ tall peaked T waves β†’ widened QRS β†’ risk for VF/asystole

    • ↓ K⁺ β†’ PVCs, VT, VF, U wave, risk of dig toxicity

  • Mg²⁺:

    • ↓ Mg²⁺ β†’ ventricular arrhythmias, torsades

    • ↑ Mg²⁺ β†’ bradycardia, heart block, asystole

  • Ca²⁺:

    • ↑ Ca²⁺ β†’ ↑ contractility, shortened QT, risk of block

    • ↓ Ca²⁺ β†’ ↓ contractility, prolonged QT, HF risk

C. FLUID + ELECTROLYTE CONTROL (RENAL)

  1. Kidneys regulate:

  • Fluid volume (Na/Hβ‚‚O balance)

  • Electrolytes: Na⁺, K⁺, Ca²⁺, Mg²⁺, H⁺/HCO₃⁻

  • Waste: urea, creatinine

  1. CO ↔ GFR link

  • Normal perfusion β†’ normal GFR β†’ normal Cr (0.6–1.2), BUN (8–20)

  • ↓ CO (HF, shock) β†’ ↓ GFR β†’ ↑ BUN/Cr, fluid retention, ↑ K⁺

  1. Renal response to low perfusion

  • Activates RAAS β†’

    • Renin β†’ Ang II β†’ vasoconstriction ↑ BP

    • Aldosterone β†’ Na⁺ & Hβ‚‚O retention, K⁺ loss

  • Chronic activation β†’ HTN, LV hypertrophy, HF progression.

D. HEMODYNAMIC RELATIONSHIPS

  • CVP (2–6 mm Hg) = right ventricular preload

    • ↑ CVP β†’ fluid overload, right-sided HF

    • ↓ CVP β†’ hypovolemia

  • PA pressures reflect pulmonary circulation & left heart function

  • PAWP (6–12 mm Hg) ~ LV preload

    • ↑ PAWP β†’ left-sided HF, pulmonary congestion

    • ↓ PAWP β†’ hypovolemia

  • SVR = systemic afterload

    • ↑ SVR (vasoconstriction) β†’ ↑ afterload β†’ ↓ SV

    • ↓ SVR (vasodilation, sepsis) β†’ hypotension, warm skin

E. OXYGENATION CONNECTION

  • CO + Hgb + SaOβ‚‚ = oxygen delivery.

  • ↓ CO OR ↓ Hgb OR ↓ SaOβ‚‚ β†’ tissue hypoxia.

  • Pulmonary congestion (HF) β†’ impaired gas exchange β†’ low PaOβ‚‚/SpOβ‚‚ β†’ more dyspnea, fatigue.

F. COMPENSATORY MECHANISMS

  • SNS activation β†’ ↑ HR, ↑ contractility, vasoconstriction

  • RAAS β†’ Na/Hβ‚‚O retention, ↑ preload

  • Ventricular hypertrophy/remodeling β†’ initially maintain CO β†’ long term β†’ stiff ventricle & HF

  • Natriuretic peptides (BNP): body’s attempt to offload fluid (cause natriuresis, vasodilation).

G. BIOMARKERS, LABS, IMAGING β€” HOW THEY FIT

  • Troponin: myocardial injury (MI, myocarditis, severe HF)

  • BNP: ventricular stretch/volume overload (HF)

  • Lipids, CRP, homocysteine: atherosclerosis / CAD risk

  • CXR: heart size, pulmonary congestion

  • ECG: rate, rhythm, ischemia, electrolyte effects

  • Echo: structure & function (EF, valves, wall motion)

  • Cath: direct visualization + pressures

πŸ”₯ 2. HIGH-YIELD PATTERN RECOGNITION β€” CHEAT CODES

I’m going to give you β€œANY…” patterns you can literally chant.

Perfusion & CO Patterns

  • ANY ↓ CO β†’

    • ↓ kidney perfusion β†’ ↓ UOP β†’ ↑ Cr/BUN

    • cool extremities + weak pulses

    • hypotension + dizziness/syncope

    • fatigue, exercise intolerance

  • ANY ↓ perfusion to brain β†’

    • confusion, restlessness, syncope, change in LOC

  • ANY fluid overload β†’

    • edema + JVD + crackles + weight gain + ↑ CVP/PAWP

  • ANY pulmonary congestion β†’

    • crackles + orthopnea + paroxysmal nocturnal dyspnea + S3 gallop

Electrical Patterns

  • ANY ↑ K⁺ β†’

    • tall peaked T waves β†’ widened QRS β†’ deadly arrhythmia risk

  • ANY ↓ K⁺ β†’

    • U waves, PVCs, VT β†’ risk increases with digoxin

  • ANY prolonged QT (↓ Ca²⁺, ↓ Mg²⁺, some meds) β†’

    • torsades risk

  • ANY severe bradycardia with symptoms (hypotension, AMS, chest pain) β†’

    • think conduction block β†’ need pacing/atropine depending on rhythm.

Fluid & Renal Patterns

  • ANY pre-renal issue (low perfusion, not damaged kidney) β†’

    • ↑ BUN:Cr ratio (>20:1)

    • concentrated urine (↑ specific gravity)

    • low UOP

    • think: dehydration, HF, shock, massive GI losses

  • ANY intrinsic renal damage (AKI/CKD) β†’

    • BUN and Cr both ↑

    • isosthenuria (fixed urine SG)

    • abnormal electrolytes (↑ K⁺, ↑ phosphate, ↓ Ca²⁺)

  • ANY RAAS activation (low perceived volume) β†’

    • HTN + edema + fluid retention β†’ can worsen HF

Pressure / Volume Patterns

  • ANY valve stenosis β†’

    • ↑ pressure upstream β†’ hypertrophy β†’ S4 β†’ HF symptoms

  • ANY valve regurgitation β†’

    • volume overload in chamber β†’ dilation β†’ S3 β†’ HF symptoms

  • ANY tamponade β†’

    • Beck’s triad: JVD + hypotension + muffled heart sounds

    • narrow pulse pressure, pulsus paradoxus

  • ANY shock (late) β†’

    • hypotension, tachycardia, cool clammy skin (except early septic), AMS, oliguria

Symptom Cluster Patterns

  • Right-sided HF β†’ JVD + peripheral edema + hepatomegaly + ascites

  • Left-sided HF β†’ crackles + dyspnea + orthopnea + S3 + fatigue

  • MI (typical) β†’ chest pain + diaphoresis + N/V + SOB + ST changes + ↑ troponin

  • Unstable angina β†’ chest pain at rest, may have ECG changes but no troponin rise.

πŸ”— 3. CROSS-CHAPTER CONNECTIONS

How Chapter 21 (assessment) feeds the other chapters:

  • Ch 22 – Arrhythmias

    • ECG basics, conduction pathway, electrolyte patterns β†’ used to ID AFib, VT, blocks.

    • Telemetry skills & alarm management directly apply.

  • Ch 23 – CAD/MI

    • Understanding ischemia vs infarction β†’ ST changes, troponin trends, chest pain assessment.

    • Stress testing, coronary angiography, biomarkers = core diagnostics.

  • Ch 24 – Structural Disorders

    • Valve anatomy + murmur locations + echo interpretation = key.

    • You already know: stenosis vs regurg β†’ S3/S4, HF signs.

  • Ch 25 – HF & Shock

    • Hemodynamic monitoring (CVP, PAWP, CO) and fluid patterns β†’ management decisions.

    • BNP and CXR findings (pulmonary edema) show decompensation.

  • Ch 26 – PVD

    • Perfusion assessment: pulses, cap refill, skin temp, color changes (pallor, dependent rubor).

    • ABI, doppler use, ulcer characteristics.

  • Ch 27 – HTN

    • BP regulation, RAAS, vessel stiffness, afterload β†’ link to LVH, HF, stroke.

  • Ch 47 – Renal Assessment

    • Perfusion dependence of kidneys, how ↓ CO hits GFR.

    • Lab interpretation: BUN, Cr, electrolytes, UOP.

  • Ch 48 – AKI/CKD

    • Pre-renal vs intra-renal vs post-renal patterns use the perfusion logic you learned here.

    • Electrolyte patterns (↑ K⁺, metabolic acidosis) tie back to cardiac arrhythmia risk.

  • Ch 49 – Urinary Disorders

    • UOP, retention vs obstruction, how post-renal issues can back up and worsen kidney function β†’ impacts volume status and BP.

Big takeaway:
Cardiac function ↔ Perfusion ↔ Renal function ↔ Volume & Electrolytes.
If you mess with one corner, the others move.

🚨 4. INTEGRATED RED-FLAG LIST (DO NOT MISS)

Vitals

  • SBP < 90 or drop > 40 from baseline

  • HR > 130 or < 40 with symptoms

  • RR > 30 or < 8

  • SpOβ‚‚ < 90% on oxygen

  • Temp > 101Β°F in post-cath/ICD/pacer/pacer/valve pt = infection concern

Perfusion

  • New confusion, restlessness, acute change in LOC

  • Cold, mottled extremities, absent pulses

  • Chest pain unrelieved by rest/nitro

Cardiac Instability

  • New-onset AFib with RVR, sustained VT, VF, complete heart block

  • ST elevation in 2+ contiguous leads

  • Symptomatic bradycardia (hypotension, syncope, chest pain)

Renal Decompensation

  • UOP < 30 mL/hr

  • Rapid rise in serum Cr or K⁺

  • New edema + weight gain > 2–3 lb in 1 day or 5 lb in a week in HF pt

Electrolyte Emergencies

  • K⁺ β‰₯ 6 with ECG changes

  • Symptomatic hypokalemia (PVCs, VT + digoxin use)

  • Mg out of range with arrhythmias

  • Ca so low or high that QT massively abnormal or tetany/arrhythmias appear

Shock Indicators

  • Hypotension + tachycardia + cool clammy skin (early septic = warm)

  • Worsening lactate (when you get into sepsis territory in later chapters)

  • Oliguria + AMS

Conduction Failures

  • 3rd-degree block

  • New bundle branch block with chest pain

  • Loss of pacer spikes or failure to capture

Lab Red Flags

  • Rising troponin

  • Sudden ↑ in BNP with worsening dyspnea

  • Sudden ↑ in BUN/Cr after contrast or hypotension

  • Platelets < 100k on heparin/antiplatelet therapy β†’ think HIT risk

Time-Sensitive Symptoms

  • MI: chest pain > 20 min, radiating, diaphoresis, N/V β†’ rapid ECG + troponin + MONA-type approach.

  • Stroke: FAST changes (face, arm, speech, time).

  • AKI: oliguria after hypotension, contrast exposure, or sepsis.

All of the above = CALL THE PROVIDER / RAPID RESPONSE.

πŸ’‰ 5. DRUG Γ— ASSESSMENT Γ— PATHO TIE-IN GRID

A. How Assessment Chooses the Drug

  • Signs of fluid overload (high CVP/PAWP, crackles, edema) β†’

    • Diuretics (loop, thiazide) to ↓ preload

  • High BP / high afterload β†’

    • ACEI, ARB, CCB, Ξ²-blocker, vasodilators (hydralazine, nitrates)

  • Angina/MI chest pain β†’

    • Nitrates + morphine + Ξ²-blockers + antiplatelets + statins

  • Low HR or block β†’

    • Hold Ξ²-blockers, NDHP CCBs (dilt, verapamil), digoxin

  • AFib with RVR β†’

    • Rate control (Ξ²-blocker, diltiazem) Β± anticoagulation

  • HF with reduced EF β†’

    • ACEI/ARB/ARNI, Ξ²-blockers, diuretics, aldosterone antagonists, SGLT2i (later chapters)

B. How Drugs Change Assessment Findings

  • Diuretics β†’

    • ↓ edema, ↓ crackles, ↓ weight, improved breathing

    • BUT watch: ↓ K⁺, ↓ Na⁺, hypotension, dehydration

  • ACEI/ARB β†’

    • ↓ BP, ↓ afterload, improved EF over time

    • BUT: ↑ K⁺, ↑ Cr, cough/angioedema (ACEI)

  • Ξ²-blockers β†’

    • ↓ HR, ↓ BP, ↓ chest pain, ↓ arrhythmia risk

    • BUT: bradycardia, hypotension, bronchospasm (nonselective)

  • Nitrates β†’

    • ↓ chest pain, ↓ preload, ↓ BP

    • BUT: headache, hypotension, do NOT give with PDE5 inhibitors (Viagra).

  • Inotropes (dobutamine) β†’

    • ↑ CO (↑ BP, warm extremities, ↑ UOP), but risk of tachyarrhythmias.

C. Renal Function & Drug Clearance

  • ↓ GFR/↑ Cr β†’

    • Adjust or avoid: many antibiotics, digoxin, ACEI/ARB (cautious), metformin, contrast, NSAIDs

    • Avoid nephrotoxins (NSAIDs, certain abx, contrast)

D. How Symptoms Tell You Therapy is Working

  • HF: ↓ dyspnea, ↓ edema, stable weight, improved activity tolerance

  • HTN: BP within target, no symptoms of hypotension

  • Angina: chest pain relieved with nitro/rest, no ST changes

  • Diuretics: weight down, crackles improving, but not hypotensive or severely hypokalemic.

πŸ“˜ 6. MINI CASE (INTEGRATED)

Case:
A 72-year-old with history of HTN, CAD, and CKD stage 3 comes to ED with SOB and orthopnea.
Findings:

  • BP 170/96, HR 112, RR 26, SpOβ‚‚ 90% on 2 L

  • JVD, bilateral crackles, 3+ pitting edema in legs

  • UOP 15 mL/hr, weight gain 6 lb in 3 days

  • BNP 1200 pg/mL, Cr 2.3 (baseline 1.6), K⁺ 5.6

  • ECG: sinus tachycardia with peaked T waves

Question: What is your priority problem to address first?
(You can answer if you want; I’ll hold rationale unless you ask.)

⚑ 7. ULTRA-HIGH-YIELD EXAM SHEET (1-PAGE CRAM)

Must-Know Numbers

  • CO: 4–8 L/min

  • EF: 55–65% (HF if < 40%)

  • CVP: 2–6 mm Hg

  • PAWP: 6–12 mm Hg

  • BNP: >100 = HF likely

  • K⁺: 3.5–5.0 mEq/L

  • Mg²⁺: 1.8–2.6 mg/dL

  • Ca²⁺: 8.8–10.4 mg/dL

  • BUN: 8–20 mg/dL | Cr: 0.6–1.2 mg/dL

  • UOP goal: β‰₯ 0.5 mL/kg/hr (~30 mL/hr)

Must-Know Labs / Biomarkers

  • Troponin = #1 test for MI

  • BNP tracks HF severity

  • Lipids + CRP = CAD risk

  • BUN/Cr ratio:

    • High = pre-renal (low perfusion)

    • Both high = intrinsic renal damage

Must-Know Symptoms & Patterns

  • Left HF: crackles, SOB, orthopnea, S3

  • Right HF: JVD, edema, hepatomegaly, ascites

  • Tamponade: JVD + hypotension + muffled heart sounds

  • Fluid overload: edema + JVD + crackles + weight gain

  • Pre-renal AKI: oliguria + ↑ BUN/Cr ratio + history of low perfusion

  • ACS/MI: chest pain, diaphoresis, N/V, ST changes, ↑ troponin

Must-Know Red Flags

  • ST elevation, chest pain not relieved by nitro

  • Troponin trending up

  • K⁺ β‰₯ 6 or ECG changes with any K abnormal

  • UOP < 30 mL/hr, rapidly rising Cr

  • Hypotension + tachycardia + AMS

  • New onset AFib with RVR, VT, VF, complete HB

Must-Know Drug Warnings

  • ACEI/ARB: watch K⁺ & Cr, cough/angioedema (ACEI)

  • Diuretics: watch K⁺, Na⁺, BP, weight & UOP

  • Ξ²-blockers: hold if HR < 60 or SBP < 90 (or per order)

  • Nitrates: no Viagra, watch BP, headache

  • Digoxin: toxic with ↓ K⁺; monitor HR & dig level

Must-Know Compensatory Mechanisms

  • SNS: ↑ HR, ↑ contractility, vasoconstriction

  • RAAS: Na/Hβ‚‚O retention β†’ ↑ preload/afterload

  • Natriuretic peptides (BNP): body trying to dump fluid

Risk β†’ Outcome Chains

  • HTN β†’ LVH β†’ HF β†’ ↓ CO β†’ renal hypoperfusion β†’ CKD

  • CAD β†’ ischemia β†’ MI β†’ ↓ EF β†’ HF β†’ arrhythmia risk

  • Sepsis β†’ vasodilation β†’ ↓ SVR β†’ ↓ BP β†’ organ hypoperfusion β†’ AKI

  • Volume overload (HF, CKD) β†’ ↑ BNP, edema, crackles, HTN

Assessment Priorities

  • ABCs first (airway, breathing, circulation)

  • Vitals trends, mental status, UOP

  • Heart sounds (S3/S4, murmurs), lung sounds, JVD, edema, pulses

  • Labs: troponin, BNP, K⁺, Cr/BUN, ABGs if respiratory issue

Intervention Priorities

  • Unstable: oxygen, IV access, ECG, notify provider/rapid response

  • Relieve ischemia: nitro, morphine, antiplatelets as ordered

  • Optimize preload/afterload/contractility based on assessment

  • Protect kidneys: monitor UOP, avoid nephrotoxins, manage volume

  • Continuous reassessment: vitals, symptoms, labs.