The correlation between the Trendelenburg position and the stroke volume variation

Area of Science:

• Anesthesiology
• Critical Care Medicine
• Cardiovascular Physiology

Background:

• Stroke volume variation (SVV) is a dynamic parameter used to assess fluid responsiveness in mechanically ventilated patients.
• SVV is influenced by various factors, including patient positioning.
• Understanding these influences is crucial for accurate interpretation of SVV.

Purpose of the Study:

• To evaluate the effect of Trendelenburg (T) and reverse Trendelenburg (RT) positions on SVV.
• To elucidate the relationship between different degrees of table slope and SVV.
• To provide insights into the impact of posture on SVV readings.

Main Methods:

• Forty-two patients undergoing elective surgery were included.
• Standardized anesthesia and volume-controlled ventilation were applied.
• Patients were positioned supine, T-Trendelenburg (-5° to -15°), and RT-Trendelenburg (5° to 15°), with SVV, cardiac output (CO), and peak airway pressure (PAP) recorded at each position.

Main Results:

• SVV significantly decreased with steeper T-positions and increased with steeper RT-positions (P=0.000).
• A 5° increase in table slope correlated with a 1% increase in SVV.
• CO and PAP showed significant changes with T and RT positions (P=0.045, P=0.027).

Conclusions:

• Patient posture significantly affects SVV measurements.
• Clinicians must consider patient positioning when interpreting SVV for fluid therapy decisions.
• These findings highlight the need for positional adjustments in SVV-guided fluid management.