The Effect of Superficial Parasternal Intercostal Plane Block on Pulmonary Function Tests After Cardiac Surgery (PIPACS)

The Effect of Superficial Parasternal Intercostal Plane Block on Pulmonary Function Tests After Cardiac Surgery

The Effect of Superficial Parasternal Intercostal Plane Block on Pulmonary Function Tests After Cardiac Surgery (PIPACS Trial): a Prospective, Double-blind, Randomised Controlled Trial.

In adult patients undergoing cardiac surgery, does adding an sPIP block to standard care compared to standard care alone result in a smaller decrease in PFTs?

Postoperative pulmonary complications pose a significant concern after cardiac surgery. Post-sternotomy pain plays a key role in impaired pulmonary function tests, ultimately increasing the risk of postoperative pulmonary complications. Parasternal intercostal plane blocks have recently emerged as a promising analgesic modality for cardiac surgery. However, the impact of parasternal intercostal plane blocks on pulmonary function tests remains unexplored. In this prospective, single-centre, double-blind, randomised controlled trial, a total of 100 participants undergoing elective cardiac surgery will be recruited. Prior to surgery, baseline pulmonary function tests will be measured. Throughout the surgical procedure, all participants will receive identical anaesthesia and surgical protocols. At the end of the surgery and after sternal wound closure, participants will be randomly assigned to one of two research arms in a 1:1 ratio. The treatment arm will receive a superficial parasternal intercostal plane block in addition to standard care, while the control arm will receive standard care alone. Pulmonary function tests, pain scores, and opioid consumption will be recorded daily until the third postoperative day. The primary outcome is the difference between pre and postoperative PFTs values. Secondary outcomes are pain scores, opioid consumption, the incidence of postoperative pulmonary complications during current hospitalisation, cardiothoracic intensive care unit, hospital length stay, and 30-day mortality. Pulmonary function tests were selected as the primary outcome due to their practicality and relevance to the postoperative course. The superficial parasternal intercostal plane block was chosen as the study intervention due to its simplicity and feasibility. The hypothesis posits that the addition of this intervention to standard care compared to standard care alone results in a smaller decrease in pulmonary function tests.

In addition to standard care, the treatment arm will receive an ultrasound-guided bilateral single-shot superficial parasternal intercostal plane block at two levels.

Anaesthesia will be induced using midazolam (0.1-0.15 mg kg-1), fentanyl (5-10 μg kg-1), and rocuronium (0.6-1.2 mg kg -1); then, after tracheal intubation, anaesthesia will be maintained using isoflurane at one MAC, along with continuous fentanyl (3-5 μg kg-1 h-1) and midazolam (20-50 μg kg-1 h-1). Moreover, patients will receive intravenous multimodal analgesics, including paracetamol 1 g, tramadol 100 mg, and dipyrone 1 g. In the cardiothoracic intensive care unit, anaesthesia will be maintained using continuous fentanyl (2-5 μg kg-1) until tracheal extubation. After tracheal extubation, patients will receive intravenous multimodal analgesic drugs around the clock, including paracetamol 3 g day-1, tramadol 300 mg day-1, and dipyrone 3 g day-1. If the patients are still in pain, rescue doses of intravenous morphine 5 mg will be administered.

The difference between daily PEFR measurements until the third postoperative day compared to baseline values

The difference between daily FEV1 measurements until the third postoperative day compared to baseline values

The difference between daily FVC measurements until the third postoperative day compared to baseline values

Postoperative pulmonary complication, based on the European perioperative clinical outcome (EPCO) criteria

Inclusion Criteria: Patients who are scheduled to undergo elective cardiac surgery via sternotomy (i.e., coronary artery bypass graft, valve replacement, valve repair). Body Mass Index (BMI) above 20 and below 40 kg m-2. Age above 18 years. Eligible to sign informed consent. Exclusion Criteria: Redo surgery. Off-pump surgeries. Pregnancy. Preoperative mechanical circulatory support (i.e., intra-aortic balloon pump, extracorporeal membrane oxygenation, ventricular assist devices). Preoperative chronic pain (i.e., fibromyalgia, post-sternotomy pain syndrome, chronic neuropathic pain). Contraindication for regional analgesia (i.e., known allergy to local anaesthetics, skin lesions in the injection site). Known allergy to one or more of the components of multimodal analgesia (i.e., opioids, paracetamol, tramadol, dipyrone). Preexisting severe pulmonary disease (i.e., an obstructive lung disease with FEV1 below 49%, restrictive lung disease with FVC below 49%, pulmonary hypertension). Criteria For Discontinuing (Postoperative Exclusion Criteria): Prolonged cardiopulmonary bypass (CPB) of more than three hours. Transfusion of more than three units of blood products. Severe coagulation disturbance requiring prothrombin complex concentrate or recombinant factor VII. Left ventricular failure with vasoactive-inotropic score (VIS) at the end of the surgery of ≥ 20. Right ventricular failure requires inhaled nitric oxide. Need for mechanical circulatory support (i.e., intra-aortic balloon pump, extracorporeal membrane oxygenation).