Shivering following cardiac surgery: predictive factors, consequences, and characteristics

Area of Science:

• Cardiovascular Surgery
• Anesthesiology
• Critical Care Medicine

Background:

• Post-cardiac surgery shivering is a frequent occurrence.
• Harmful hemodynamic changes associated with shivering are not well understood.
• Predictors of shivering risk after cardiac surgery require further definition.

Purpose of the Study:

• Identify factors associated with shivering risk post-cardiac surgery.
• Characterize hemodynamic and temperature profiles in shivering versus non-shivering patients.
• Determine if shivering is cold-induced using electromyogram analysis.

Main Methods:

• A descriptive, time-series study design was employed.
• 10 shivering and 10 non-shivering adult patients were monitored for 4 hours post-cardiac surgery.
• Continuous measurements included skin and pulmonary artery temperatures, heart rate, arterial pressure, and intermittent electromyogram recordings.

Main Results:

• Lower skin temperature was a significant predictor of shivering risk.
• Shivering patients exhibited higher initial heart rates (13.6 bpm higher).
• Electromyogram patterns confirmed shivering as cold-induced; nitroprusside use was higher pre-shivering.

Conclusions:

• True shivering occurs post-cardiac surgery, predicted by skin temperature and elevated heart rate.
• Core temperature, age, weight, and surgical duration were not significant predictors.
• Shivering may indicate underlying hemodynamic instability in post-cardiac surgery patients.