Ultrasound-guided erector spinae plane block (ESPB) is an interfascial blockade during thoracic anesthesia, first described by Forero in 2016, and is highlighted by technically feasibility and less complication rate. The patient is placed as decubitus position. The anesthesiologists use echo to identify the ipsilateral transverse process at T5 level, and insert the needle to 2-3 cm lateral to the spinous process until contact the transverse process. Then the injected local anesthetic will penetrate via erector spinae muscle to paravertebral space to affect and relieve pain.

Inclusion Criteria:

• adult patients, over 20 years old, u
• undergoing elective uniportal VATS lobectomy.

Exclusion Criteria:

• patient refusal,
• body mass index > 35 kg/m2,
• American society of anesthesiologists (ASA) grade above 3,
• contraindication to nerve block,
• allergy to analgesic agents,
• regular opioid used for chronic pain prior to this time surgery,
• conversion to thoracotomy or VATS procedure,
• postoperative intubation,
• postoperative intensive care unit admission.