In cardiac surgery, the most common cause of pain during the first two days postoperatively is median sternotomy. In a study in which 705 patients who had undergone cardiac surgery were followed up prospectively, postoperative 24 hours pain scores ranging from 5.3 to 6.5 out of 10 with deep breathing and coughing were shown. In these patients, it may increase the frequency of atelectasis due to reasons such as failure in pain control, weak coughing, and limitation of movement, and these may lead increase in morbidity and hospital stay. Although nonsteroidal analgesics and opioids are used successfully in the control of this severe pain, they are far from being ideal analgesics alone due to their side effects such as kidney damage, bleeding risk, sedation, respiratory depression, itching, nausea, and vomiting. The complications of neuraxial techniques seem to be the disadvantages of these methods. Erector spinae plane (ESP) block is one of the regional anesthesia techniques that has been shown to be effective in reducing sternotomy pain in sternotomy-guided cardiac surgeries.~The Erector spinae plane (ESP) block was first described by Forero in 2016. In this block technique, a local anesthetic is given to the plane between the erector spinae muscle and the vertebral transverse process. The dorsal and ventral branches of the spinal nerves are blocked in this plane. However, due to individual regional anatomical differences, there is not enough data to determine the optimum volume at which the appropriate spread of local anesthetic will occur. Volume-based cadaver studies have some handicaps since they do not have the characteristics of living tissue.~This study aims to compare the postoperative analgesic efficacy of ESP block applied at the same dose but with different local anesthetic volumes in cardiac surgeries to be performed with sternotomy.
Even though erector spinae plane (ESP) block is shown to be efficient in cardiac surgery, it is still controversial how much volume is necessary for efficient analgesic effect for sternotomy and drain tube pain relief. This study aims to investigate the optimal local anesthetic volume (20 mL versus 30 mL) with ESP block for open-heart cardiac surgery.