Serratus Planus Block After Minimally Invasive Cardiac Surgery

Many patients receiving MICS (minimally invasive cardiac surgery) suffer from significant postsurgical pain. While systemic analgesic therapy has been proven to be insufficient in a great number of patients, significant unwanted side effects might occur. Therefore, the investigation of peripheral nerve blocks such as SAPB with potential for high benefit and low risk for adverse effects as new treatment options for thoracotomy-pain is relevant. Previous randomized double-blind investigations of this novel technique are lacking. At this moment our department's current standard of care is that, SAPB is performed in patients after MICS in our department if the treating anesthetist is experienced in the procedure and the patient receives i.v. analgesia only without nerve block is he or she is not. If we are able to show a benefit for patients in the SAPB arm, the nerve block may constitute a new standard of care for all MICS patients no only in our department but also after MICS in general. Patients ≥18 years of age, being treated in the cardiothoracic ICU after elective cardiac surgery performed via lateral minithoracotomy (mitral valve, tricuspid valve, atrial septal defect closure) will be included after signed informed consent before surgery. Allocation concealment is guaranteed by opening of the concealed envelope and performance of the ultrasound guided SAPB or ultrasound only by medical personnel not involved in any of the study procedures. Randomization will be carried out by a web-based software ('randomizer,). The intervention will be performed after ICU arrival but under sedation and analgesia before extubation to minimize patient discomfort and to ensure double blinding. Efficacy will be evaluated using Pain Scoring by visual analogue scale (VAS), opioid requirements, postoperative complications, need for rescue analgesia, lung function tests and markers of myocardial stress and inflammatory parameters in the early postoperative period according to our cur