Central Venous Pressure (CVP) is the pressure within the thoracic vena cava near the right atrium, reflecting right ventricular preload (volume status) and venous return to the heart.
Normal Central Venous Pressure (CVP) Range
👉2–8 mmHg (or 4–12 cm H₂O depending on the system used, Normal value varies in some countries.)
Clinical Significance Central Venous Pressure (CVP)
CVP helps assess:
👉Fluid volume status
👉Right-sided heart function
👉Venous return
👉Effectiveness of fluid resuscitation
High CVP Causes:
👉Fluid overload (hypervolemia)
👉Right heart failure
👉Pulmonary hypertension
👉Cardiac tamponade
👉Tension pneumothorax
👉Tricuspid valve disease
Low CVP Causes
👉Hypovolemia (bleeding, dehydration)
👉Vasodilation (e.g., septic shock)
👉Third-spacing (burns, trauma)
Measurement of Central Venous Pressure (CVP)
👉Via central line (e.g., subclavian, internal jugular)
👉Transducer leveled at the phlebostatic axis (4th intercostal space, mid-axillary line)
👉Patient should be in supine position
👉Must be zeroed and calibrated properly
👉Measured at end-expiration
Physiological Concepts Central Venous Pressure (CVP)
1. Venous Return and Preload
👉CVP reflects the amount of blood returning to the heart (venous return).
👉It also represents right ventricular end-diastolic pressure (RVEDP) in the absence of tricuspid valve disease.
👉Venous return must match cardiac output in a steady state. CVP helps regulate this balance.
2. Starling’s Law of the Heart
👉The greater the venous return (preload), the more the right ventricle stretches → stronger contraction → increased cardiac output.
👉But excessive CVP can mean the heart is overloaded and struggling to pump efficiently.
3. Intrathoracic Pressure Effects
👉Spontaneous inspiration ↓ intrathoracic pressure → ↓ CVP (suction effect).
👉Positive pressure ventilation ↑ intrathoracic pressure → ↑ CVP (can falsely elevate readings).
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Waveform Physiology of Central Venous Pressure (CVP)
The CVP waveform correlates with right atrial pressure changes during the cardiac cycle:
👉a wave – Atrial contraction
👉c wave – Tricuspid valve bulging during ventricular systole
👉x descent – Atrial relaxation
👉v wave – Passive venous filling of the atrium
👉y descent – Tricuspid valve opening and ventricular filling
Clinical Relevance
👉Low CVP → Consider fluid resuscitation
👉High CVP → Evaluate for fluid overload or right heart dysfunction
👉Always interpret in context with BP, urine output, mental status, and other hemodynamic data
Nursing Considerations for Central Venous Pressure (CVP)
👉Monitor for signs of infection at central line site
👉Maintain sterile dressing changes
👉Ensure transducer is zeroed and leveled correctly
👉Document waveform and pressure reading
👉Correlate with other vital signs (BP, HR, urine output)
