Postoperative Analgesia and Ventilation After Cardiac Surgery

Overview

Cardiac surgery performed via median sternotomy is associated with significant postoperative pain due to extensive tissue trauma, sternal bone healing, and mediastinal retraction. Inadequately controlled postoperative pain represents an important source of morbidity in these patients and may adversely affect respiratory mechanics, leading to hypoventilation, atelectasis, and hypoxemia. These complications can delay extubation, prolong the duration of mechanical ventilation, and increase the length of stay in the intensive care unit (ICU). In addition, insufficient pain control may trigger sympathetic activation, resulting in increased myocardial oxygen consumption, a higher risk of arrhythmias, and impaired immune function. Traditionally, systemic opioids have been the cornerstone of postoperative pain management in cardiac surgery; however, opioid-based analgesia is associated with several adverse effects, including respiratory depression, sedation, nausea and vomiting, gastrointestinal dysfunction, and prolonged mechanical ventilation. These limitations have led to increasing interest in multimodal analgesia strategies aimed at improving postoperative pain control while reducing opioid consumption and related complications. In this context, regional analgesia techniques have emerged as important components of multimodal pain management protocols in cardiac surgery. The aim of this study was to evaluate the effects of fascial plane blocks used as part of postoperative analgesia on postoperative pain control, opioid consumption, respiratory parameters, mechanical ventilation duration, and early oxygenation in patients undergoing open heart surgery via median sternotomy, compared with patients receiving conventional analgesic management.

Cardiac surgery is a major surgical discipline performed on hundreds of thousands of patients worldwide and is becoming increasingly common with technological advances. Median sternotomy remains the standard surgical approach for open-heart procedures, most notably coronary artery bypass grafting (CABG) and valve reconstruction or replacement.1,2 The pain resulting from sternotomy-associated extensive tissue injury, sternal bone regeneration, and mediastinal retraction is both severe and multidimensional in nature, arising from widespread irritation of the thoracic wall, pericardium, pleura, and the involved neural structures.3 Inadequately controlled postoperative pain is a significant source of morbidity in cardiac surgery and leads to serious clinical consequences. Acute pain adversely affects respiratory mechanics, predisposing patients to hypoventilation, atelectasis, and hypoxemia; it prolongs the extubation process and increases the duration of intensive care unit (ICU) stay.4,5 Insufficient analgesia can also increase myocardial oxygen demand through sympathetic activation, heighten susceptibility to arrhythmias, and compromise immunological integrity.6 In the long term, the risk of acute pain transitioning into chronic post-sternotomy pain cannot be overlooked; this condition is known to permanently impair patients' quality of life and significantly restrict functional capacity.7 Systemic opioids have traditionally formed the cornerstone of postoperative pain management in cardiac surgery. However, opioid-based analgesia is associated with a range of adverse effects including respiratory depression, sedation, nausea and vomiting, ileus, and prolonged mechanical ventilation.8 These adverse effects are particularly consequential in the vulnerable patient population of cardiac surgery, contributing to increased clinical complexity, greater utilization of hospital resources, and potential increases in mortality.9 In this context, multimodal analgesia strategies aimed at reducing opioid consumption, limiting side effects, and accelerating postoperative recovery are gaining increasing importance.10 Regional anesthesia techniques have been rapidly integrated into cardiac surgical practice in recent years as an indispensable component of multimodal analgesia protocols. Although thoracic epidural anesthesia and paravertebral block have long been established methods with proven efficacy, their use is significantly limited by factors such as coagulopathy, systemic heparinization in cardiac surgery, and high bleeding risk.11,12 Superficial fascial plane blocks, developed alongside the widespread adoption of ultrasound technology, offer a more favorable safety profile and are attracting increasing interest in cardiac surgical applications.13 The pecto-intercostal fascial plane block (PIFB) is a relatively novel technique based on local anesthetic injection into the fascial plane between the pectoralis major muscle and the external intercostal muscles. By targeting the intercostal nerve branches of the anterior thorax and afferent fibers of the cutaneous pectoral branches, PIFB provides effective analgesia along the sternotomy incision adjacent to the sternum.14,15 The serratus anterior plane block (SAPB), on the other hand, blocks the intercostobrachial nerve and thoracic intercostal nerve branches innervating the lateral thorax through local anesthetic injection into the fascial plane between the latissimus dorsi and serratus anterior muscles and the ribs.16,17 The combination of these two blocks establishes a complementary analgesic coverage encompassing the sternotomy incision, the parasternal region, and the lateral thoracic wall.18 Both techniques possess characteristics that distinguish them in cardiac surgical patients: superficial anatomical targets, ease of ultrasound-guided application, and a safe-use profile even during anticoagulation.19 Nevertheless, studies evaluating the combined application of PIFB and SAPB in open-heart surgery remain very limited in number, and comprehensive data assessing the impact of this combination on postoperative pain control, opioid consumption, and respiratory function are still insufficient. The aim of this study is to evaluate the effect of fascial plane block on postoperative pain scores, opioid consumption, respiratory parameters, and ICU outcomes in patients undergoing open-heart surgery via sternotomy, in comparison with patients receiving conventional analgesia.