Median sternotomy is commonly used in cardiac surgery and is associated with significant intraoperative and postoperative pain, often requiring substantial opioid administration. High opioid use during cardiac surgery may contribute to adverse effects such as respiratory depression, delayed extubation, postoperative nausea and vomiting, and prolonged intensive care unit stay. Therefore, effective opioid-sparing strategies are an important component of modern perioperative care.

The deep parasternal intercostal plane (DPIP) block is a regional anesthesia technique that targets the anterior cutaneous branches of the intercostal nerves, which are responsible for transmitting pain from the sternum and adjacent tissues. When performed under ultrasound guidance, this block allows precise local anesthetic deposition while minimizing the risk of pleural or vascular injury.

The purpose of this randomized controlled study is to evaluate whether a preoperative ultrasound-guided DPIP block reduces intraoperative opioid consumption in adult patients undergoing elective cardiac surgery via median sternotomy. Patients will be randomly assigned to receive either a bilateral DPIP block in addition to standard general anesthesia or standard general anesthesia alone.

The primary outcome of the study is total intraoperative opioid consumption. Secondary outcomes include time to extubation, postoperative opioid consumption within the first 24 hours, postoperative pain scores, and the incidence of opioid-related adverse effects. The results of this study may help define the role of the DPIP block as part of a multimodal, opioid-sparing analgesic strategy in cardiac surgery.

Adequate pain control during and after cardiac surgery via median sternotomy remains challenging despite advances in perioperative care. Opioids continue to be the mainstay of analgesia; however, excessive intraoperative opioid administration has been associated with delayed extubation, respiratory complications, postoperative nausea and vomiting, and prolonged intensive care unit stay. As part of enhanced recovery protocols, regional anesthesia techniques that provide effective opioid-sparing analgesia are increasingly emphasized.

The deep parasternal intercostal plane (DPIP) block is a relatively novel ultrasound-guided regional anesthesia technique that targets the anterior cutaneous branches of the intercostal nerves within the fascial plane between the internal intercostal and transversus thoracis muscles. Compared with more proximal neuraxial or paravertebral techniques, the DPIP block offers a more localized and anatomically specific approach to sternotomy-related pain while potentially reducing the risk of serious complications.

In this prospective, randomized controlled trial, adult patients scheduled for elective cardiac surgery via median sternotomy will be allocated to one of two parallel groups. Patients in the intervention group will receive a bilateral ultrasound-guided DPIP block performed preoperatively after induction of general anesthesia, in addition to standardized general anesthesia management. Patients in the control group will receive standardized general anesthesia alone, without a regional block. Perioperative anesthetic management, including opioid administration, will follow institutional protocols and will be guided by routine clinical parameters.

The primary objective of the study is to assess the effect of the preoperative DPIP block on total intraoperative opioid consumption. Secondary objectives include evaluation of early recovery parameters such as time to extubation, postoperative opioid requirements within the first 24 hours, postoperative pain intensity, and the occurrence of opioid-related adverse events. Safety outcomes related to the block procedure will also be recorded.

This study is designed to provide clinically relevant data on the role of the DPIP block as part of a multimodal analgesic strategy in cardiac surgery. By focusing on intraoperative opioid consumption and early recovery outcomes, the trial aims to clarify whether preoperative application of this targeted regional technique can contribute to improved perioperative management and opioid-sparing anesthesia in patients undergoing median sternotomy.

Inclusion Criteria:

Adults aged 18 to 65 years Scheduled to undergo elective cardiac surgery via median sternotomy Planned general anesthesia Able to provide written informed consent

Exclusion Criteria:

Known allergy or contraindication to local anesthetics Coagulation disorders or ongoing anticoagulant therapy that contraindicates regional anesthesia Infection at or near the planned injection site Pre-existing chronic pain conditions requiring long-term opioid use Severe cognitive impairment or inability to communicate pain intensity Emergency surgery Refusal or inability to provide informed consent

Individual participant data will not be shared, as the study is a single-center clinical trial and data sharing was not included in the original study protocol or approved by the institutional ethics committee. De-identified aggregate data will be reported in scientific publications.

Participants will be blinded to group allocation, as the deep parasternal intercostal plane block will be performed after induction of general anesthesia. Postoperative outcome assessments, including pain scores, opioid consumption, and time to extubation, will be conducted by an independent outcome assessor who is blinded to group assignment. The anesthesiologist performing the regional block will not be blinded due to the nature of the intervention.