Cardiovascular Disorders – Surgical Patient Management (Comprehensive Study Notes)

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Scope & Integration with Other Chapters
• Chapter 6 should be studied in parallel with Chapters 7 (Shock) and 8 (Monitoring).
• Focus: clinical assessment, diagnosis and first‐line management of cardiac disorders in surgical patients.

Why Early Recognition Matters
• Even with a patent airway & adequate ventilation, any fall in cardiovascular efficiency → ↓O$_2$ delivery → cellular hypoxia → organ failure.
• Pathologies span:
– ↓ circulating volume (eg haemorrhage).
– “Pump” failure (eg myocardial ischaemia, arrhythmias).
– After-load anomalies (eg sepsis → vasodilatation / vasoconstriction).
• Early signs can be subtle (slight change in pulse or BP).
• National Early Warning Score (NEWS) advocated for prediction & prevention.

Learning Outcomes

1. Judge adequacy of CVS function.
2. Decide if CVS is root cause of illness.
3. Allocate correct location & urgency of treatment.
4. Start evidence-based management of common cardiac pathologies.
5. Escalate & communicate with specialists promptly.

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NEWS as a ‘Trigger’ Tool
• Detect derangements → mandate review or escalation.

Principles of Examination
• Must be systematic, well-documented, and repeated to gauge response to interventions (eg fluid bolus).
• Consider usual cardiac drugs & comorbid organs (renal, CNS).
• Plan for route of admin when patient is $\text{NPO}$.

Immediate Assessment – ‘Two Layers’

1. Rapid ABCDE to rule out need for CPR.
2. Full CCrISP algorithm while resuscitating.

Maintain Diagnostic Openness – Don’t force findings to fit a favourite diagnosis; hypovolaemia, sepsis, pump failure & PE need very different therapies.

Cardio-Respiratory Interdependence
• Dyspnoea ↑ suspicion of either system.
• Eg: Tension pneumothorax ⟹ CVS signs; LV failure ⟹ respiratory signs.
• Renal & CNS functions are sensitive end-organ markers of perfusion; confusion suggests cerebral hypoperfusion/hypoxia.

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Identifying Life-Threatening CVS Disorders
• LOOK – pallor, poor peripheral perfusion, CVP clues, overt/hidden haemorrhage, soft-tissue swelling.
• LISTEN – patient’s subjective cues: thirst, orthostatic faintness (hypovolaemia); orthopnoea (pulmonary oedema); chest or new cavity pain.
• FEEL – central pulses (carotid/femoral) if radial absent; assess rate, quality, regularity; palpate for distension, tenderness, ischaemia; check cap-refill & skin temperature.

Practice Points
• Auscultate heart: normal sounds? gallop? new murmur?
• Unwell surgical pts benefit from $15\;\text{L min}^{-1}$ O$_2$ + a prompt fluid challenge during assessment.

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Full Patient Assessment: Note & Chart Review
• Do charts before in-depth dialogue → unbiased data set.
• Review baseline comorbidity & peri-op course.
• Evaluate absolute values and trends:
– RR, FiO$2$, SpO$2$
– HR & rhythm
– BP (sys/diast)
– CVP (if present)
– Temp
– UO
– IV line details
– Fluids prescribed vs given
– All drain outputs.

• Scan drug chart for cardio-active drugs; check POC or lab results.

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Respiratory Rate – The Sentinel Sign
• Most sensitive; earliest to change.
• Low RR → opiate/CNS depression or low CO.
• High RR → any shock, resp. disease, cardiac failure, hypoxia, metabolic acidosis.

Heart Rate & Rhythm
• HR rises to maintain $CO = HR \times SV$.
• β-blockers / pacing may blunt response.
• Autonomic triggers: pain, fear, fever.
• Watch for dysrhythmia as first clue to biochemical issues or MI.
• Tachy/arrhythmia ↓ diastolic time ⟹ ↓ myocardial perfusion → silent ischaemia.

Blood Pressure
• Late marker. Think organ perfusion rather than numbers.
• Correlate with urine output: “renal barometer.”
• For a chronic hypertensive (baseline $180/100\;\text{mmHg}$), $110/70$ = profound hypotension.

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JVP / CVP vs Capillary Refill Time (CRT)
• Ward CVP uncommon; CRT (press nail/sternum $5\,\text{s}$) is quicker.
• Collapsed neck veins at $45^{\circ}$ = low CVP; distended = high.
• Best guide is dynamic response to fluid bolus, not single reading.

When to Insert CVP Line
• Persistent hypotension despite fluids & no bleeding.
• Threshold to involve Critical Care should be low.

Box 6.1 Highlights
• Prolonged CRT ⇒ hypovolaemia, continued bleed, sepsis vasodilatation, low CO.
• High CVP ⇒ overload, RV failure, PE, tamponade, chronic lung disease.

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Temperature Nuances
• Low-grade pyrexia post-MI or endocarditis (look for new murmur, anaemia).
• Circadian rise in warm ward.

Fluid Balance
• Compare cumulative ins/outs; UO trend more useful than absolute.
• Watch for gradual ↓ UO rather than acute anuria (often blocked catheter).
• Early ↓ UO often correlates with earlier subtle vitals changes—construct timeline.

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Lines, Drains & Tubes
• Need large-bore IV for rapid bolus.
• “Tissued” cannula = dual harm (extravasation injury + therapeutic failure).
• Maintain asepsis—line sepsis = major HAI.
• Drains: non-swinging chest tube ⟹ possible tension PTX; abdominal drain stops ⟹ concealed blood/pus.
• Smelly, green/brown fluid → GI leak.
• Surgical patients usually hypovolaemic > overloaded; oedema in elderly may still mask hypovolaemia.
• Give small, repeated boluses in tenuous hearts; consider HDU/ICU.

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Drug Chart Review
• Missed regulars (β-blocker, ACE-I, digoxin) while NPO → rebound HTN, arrhythmia.
• Renal injury → drug accumulation (eg digoxin toxicity).

Case Notes & History
Gather time course, nature of pain, dyspnoea, exercise tolerance. Use nurses & relatives to fill gaps.

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Focused Examination (CVS Section of Full Assessment)
Look – Alertness after O$_2$? Colour? Peripheral oedema? JVP visible?

Listen – Basal creps (LVF), cardiac wheeze (early LVF), extra sounds or new murmurs (time to carotid pulse; diastolic murmurs always pathological).

Feel – Limb temp, CRT, hepatomegaly/ascites (RHF). See Box 6.2 for low-CO indicators: cool clammy skin, thready pulse, cyanosis, oliguria, confusion, metabolic acidaemia.

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Laboratory & Imaging Essentials
• Minimum set: Hb, WCC, platelets, $K^+$, $Mg^{2+}$.
• Re-check if deterioration occurred since last sample.
• Hb target $\approx80\,g\,L^{-1}$ stable; higher if bleeding or acute cardiac event.
• Electrolytes vital—low $K^+$/$Mg^{2+}$ favour arrhythmia.
• Troponin I/T at $\ge6\,\text{h}$ post symptom onset; interpret in sepsis/CRF with caution (false positives).
• BNP helpful where available.

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Chest Radiography
• Distinguish cardiac vs respiratory causes; always compare old films.
• Portable CXR preferred for unstable pts.

Electrocardiography Basics
• Bedside monitor rhythm strip ≠ diagnostic; obtain 12-lead.
• Routine reading algorithm (Table 6.1): Axis → Rhythm → Rate → P → PR → QRS → ST → T → U.

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Electrical Axis & Precordial Morphology
• Normal R wave progression V1→V6; S wave depth inversely mirrors.
• Heart rotates around near-vertical axis ⇒ varying QRS polarity (non-pathological).
• Axis determined via hexaxial reference; example in Figure 6.3.

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Axis Interpretation
• More deviation toward a lead → larger deflection in that lead.
• Example stresses comparing Lead II vs aVL.

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Normal ECG Ranges (Table 6.2)
• $QRS <0.12\,\text{s}$; tachy $>100\,\text{bpm}$; brady <60.
• Electrical axis normal $+90^{\circ}\to -30^{\circ}$ (vertical in tall, horizontal in stocky).
• Normal QT $\approx0.35\,\text{s}$ but rate-dependent.
• Normal T upright except aVR; may invert III, V1-2.

Figures 6.4–6.5 illustrate PQRST labelling and a normal 12-lead.

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From Data to Decision
• Synthesize findings → working dx → plan → treat → reassess.
• CVS has huge reserve; overt signs mean advanced pathology—act, don’t watch.

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Hypotension
• Most common CVS issue in surgical wards; differential broad.

Tachyarrhythmias (Table 6.3)
• Rule out “4 H’s”: hypovolaemia, hypoxia, hypokalaemia, hypomagnesaemia.
• Check usual meds (eg digoxin).
• Valsalva may terminate SVT temporarily.

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Pharmacologic Caveats
• Know drug actions & contraindications; if unsure, don’t give—seek help.
• Long-term AF/flutter → consider anticoag after acute phase (not surgical trainee’s remit).
• DC cardioversion for rapid rate or compromise; less effective in chronic AF.
• Pacing/ablation = specialist domain.

Ventricular Tachyarrhythmias
• Distinguish VT vs SVT with aberrancy (Figures 6.6–6.7; Table 6.4).
• VT needs urgent cardioversion, esp. if compromised.
• SVT may respond to adenosine $6\,mg$ → $12\,mg$ (avoid in asthma, with dipyridamole).

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Ventricular Ectopics (VEs)
• Uni- vs multifocal; danger is $R\text{ on }T$ → VF.
• Treat if >1 VE per 6 beats or multifocal; search for triggers: sepsis, hypo-electrolytes, MI.

Common Atrial Tachycardias

1. Sinus Tachy (gradual onset, normal Ps, rate ≤$160$): treat cause.
2. Paroxysmal SVT (rate $150–250$, often no visible P): may need adenosine/verapamil.
3. Atrial Fibrillation: irregularly irregular; postoperative causes = hypovolaemia, hypoxia, $K^+$/$Mg^{2+}$ loss.
   • If adverse signs (hypotension, CHF, chest pain) → DC shock or IV amiodarone.
   • Otherwise correct triggers & consider digoxin/amiodarone.
4. Atrial Flutter: saw-tooth $300\,\text{min}^{-1}$; treat like SVT or cardiovert.

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Chamber Hypertrophy & Bundle Branch Blocks
• LVH: tall R in I, aVL, V4-V6; deep S in V1-3; causes = HTN, AS.
• RVH: right axis dev, tall R in V1; causes = pulmonary HTN, cor pulmonale.
• LBBB: ‘M’ QRS in V5-6; masks MI patterns.
• RBBB: ‘M’ in V1-3; with left axis deviation = bifascicular block → consider pacing.

Bradyarrhythmias (Box 6.4)
• Autonomic (pain, ICP, drugs) vs non-autonomic (MI, sepsis, hypoxia, hypothyroid).
• Symptomatic → atropine $0.6–1.2\,mg$, maybe pacing.

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Myocardial Infarction
• Peri-operative MI has high mortality; silent presentation common (dyspnoea, confusion, hypotension).
• Classic ECG:
– Anterior: ST↑ V1-4.
– Inferior: ST↑ II, III, aVF with reciprocal ST↓ I, aVL.
• ST elevation >1\,mm significant; remember early normal ECG does not exclude MI.

Immediate Management

1. ABCDE + $15\,L\,\text{min}^{-1}$ O$_2$.
2. Morphine $1–2\,mg$ IV q2 min titrated (+ anti-emetic).
3. GTN (spray/tab).
4. Aspirin $300\,mg$ PO/PR if surgical bleeding risk acceptable.
5. Correct anaemia & electrolytes.
6. Serial ECGs & troponins.

Definitive Reperfusion (Cardiology led)
• Primary PCI ± heparin / GP IIb/IIIa inhibitor preferred.
• Fibrinolysis (alteplase) if PCI unavailable and bleeding risk acceptable.

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Acute Coronary Syndromes (ACS)
Spectrum: STEMI, Non-STEMI, Unstable Angina.
Pathophysiology: plaque rupture → thrombosis → platelet aggregation & spasm.

ACS Treatment Pillars (after surgical discussion):
• Dual antiplatelet (aspirin + clopidogrel/prasugrel).
• Anticoagulation (heparin/LMWH).
• β-blockade (if no CCF/brady/hypotension).
• Tight glycaemic control (\text{glucose}<11\,mmol\,L^{-1}).
• Early cardiology review for risk stratification ± angiography.

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Cardiac Failure – Pathophysiology Review
• Determinants:

1. Preload (ventricular filling).
2. Intrinsic Contractility.
3. Afterload (resistance).
   • Frank-Starling: in failure, curve shifts ↓ & →; tachycardia decreases diastolic time → worse filling & coronary flow.

Common Post-op Triggers (Box 6.6)
• Fluid overload (most frequent).
• Ischaemia/MI, arrhythmia.
• Pneumothorax, tamponade, PE, valve lesions.

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Cardiogenic Pulmonary Oedema
• Presentation: acute dyspnoea, orthopnoea, pink frothy sputum, basal creps, gallop, high BP.
• CXR: fluid in horizontal fissure, bat-wing perihilar shadow, Kerley B lines.

Management (ABCDE-based)

1. Sit upright, O$_2$, consider CPAP.
2. IV furosemide $40–80\,mg$.
3. Small IV opioids (morphine $2.5–5\,mg$) for preload/afterload reduction & anxiety.
4. Nitrates (patch or IV).
5. Stop unnecessary infusions; monitor CVP.
6. If refractory → HDU/ICU, invasive monitoring, inotropes/vasodilators.

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Cardiogenic Shock
• Defined: SBP $<90\,mmHg$ or $>30\,mmHg$ below baseline + evidence of low perfusion.
• Spiral: ↓CO → hypotension → organ hypoxia → ↑catecholamines → tachycardia → ↑afterload & O$_2$ demand → worse ischaemia.
• Requires invasive monitoring, judicious fluids, inotropes, vasodilators, early intensivist input.

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Surgical Risk After Recent MI
• Reinfarction risk: $60\%$ <3 wk; $27\%$ 3 mo; $11\%$ 3–6 mo.
• Delay elective ops if feasible.
• Continue cardiac meds peri-op (except ACE-I/ARB morning of surgery).
• Assess reserve via echo or CPET.

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Hypertension
• Avoid abrupt cessation of long-term agents (except ACE-I/ARB pre-induction).
• Hypertensive crisis ≥$220/120\,mmHg$ + organ signs → urgent cardiology.

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Pacemakers & Surgery
• Pre-op cardiology check mandatory; ICD function may need suspension.
• Diathermy precautions: place earth pad far from generator, use short bursts, prefer bipolar.
• Continuous ECG during procedure.

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Bradycardia & Heart Block
• High-risk (eg bifascicular block) need elective pacing.
• Atropine first-line; isoprenaline infusion under specialist guidance.

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MI ECG Timing Table
• Peaked T: seconds.
• ST elevation: hours.
• Pathological Q: hours–days.
• T inversion: hours–days.
ECG examples illustrated (anterior vs inferior vs posterior).

NICE CG167 – interventional pathway summary.

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Heart Failure Treatment Steps Recap

1. ABCDE + O$_2$.
2. Halt IV fluids if overload.
3. Pharmacology: loop diuretic, GTN, diamorphine.
4. Identify precipitant (arrhythmia, PE, tamponade).
5. Consider CPAP & CVP monitoring.
6. Early HDU transfer.

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Key Take-Home Messages
• Early correction of abnormal signs prevents collapse.
• Normal obs do not guarantee normal perfusion—validate with trends & adjunct tests.
• Always formulate a written management plan with timed reassessment.
• Escalate to higher care proactively in chronic or newly unstable CVS disorders.
• Involve anaesthetics, cardiology, critical care without delay.

Suggested Guidelines for Further Reading
• NICE QS68 (ACS), CG167 (STEMI), CG187 (Acute Heart Failure), CG180 (AF).