Infrared Thermography to Evaluate the Effect of Paravertebral Block

Changes of Skin Temperature for Evaluation of Paravertebral Block: A Prospective Observational Study Using Infrared Thermography

The aim of this prospective observational study was to evaluate the changes of skin temperature after the paravertebral block measured by infrared thermography.

Methods: Patients scheduled for elective surgery with paravertebral block will receive infrared thermography measures 5 min before the block and continous to 20 min after the block. The sensitivity, specificity of infrared thermography as diagnostic methods will be determined by receiver operator characteristic analysis.

Inclusion Criteria:

• With informed consent
• American Society of Anesthesiologists physical status Ⅰ-Ⅱ
• Undergo elective surgery with planned paravertebral block

Exclusion Criteria:

• Refusal to participate in the study
• pre-existing infection at the block site
• younger than 18-yr-old
• BMI>35
• significant thoracic kyphoscoliosis
• Those who had taken vasodilatory drugs before surgery
• history of previous thoracic or breast surgery
• Preoperative analgesic medications
• Any contraindications to peripheral nerve block such as coagulation abnormalities, allergy to local anaesthetics, peripheral neuropathy.