Transversus Thoracis Plane Block Versus Parasternal Intercostal Nerve Plane Block for Cardiac Surgery

Role of Transversus Thoracis Plane Block Versus Parasternal Intercostal Nerve Plane Block in Enhanced Recovery Program After Cardiac Surgery: A Randomized Controlled Study

Traditionally postoperative pain management after cardiac surgery has been based on opiate analgesics. However, opiates have some undesirable dose-related side-effects such as nausea, constipation, vomiting, dizziness, mental confusion and respiratory depression, which substantially influence patient recovery and may delay discharge after surgery.

The American Society of Anesthesiologists has endorsed multi- modal analgesia, involving multiple analgesics with differing modes of action, to reduce the overreliance on opioid-based postsurgical analgesic regimens and the associated adverse effects.

The safety of using the transversus thoracis muscle plane block (TTP) or the parasternal intercostal nerve block (PSI block) for cardiac surgeries allow to make the option of using opioids alone and the possibility of its complications not the rule in post-operative pain relief in cardiac surgeries.

In the current study, improving the quality of the transversus thoracis muscle plane block (TTP) or the parasternal intercostal nerve block (PSI block) for cardiothoracic surgeries by enhancing post-operative pain relief becomes more and more required to cope up with the new surgical modalities.

Enhanced Recovery After Surgery (ERAS) is an international effort to develop perioperative programs aimed at optimizing patient outcomes and healthcare delivery efficiency. These programs are composed of intervention bundles based on the principles of best practice, standardized and consistent healthcare delivery, regular audit, and team feedback, all with a patient-centered focus. Implementation of such programs has resulted in patient and healthcare benefits, including promising early results within the cardiac surgical community.

A perioperative, multimodal, opioid-sparing, pain management plan is classified as B-NR (B-level evidence, nonrandomized studies) in the classification of recommendation and level of evidence. The ERAS Cardiac Society's grading of this recommendation is appropriate because it is a laudable goal that requires additional research. Areas of investigation to refine postoperative pain management include the following: managing patient and provider expectations, individualizing the dose and types of analgesics, consideration of the potential cardioprotective effects of opioids, and incorporating nonpharmacologic approaches to pain management such as regional anesthesia.

Pain after cardiac surgery is caused by several factors; sternotomy, sternal/rib retraction, pericardiotomy, internal mammarian artery harvesting, saphenous vein harvesting, surgical manipulation of the parietal pleura, chest tube insertion and other musculoskeletal trauma during surgery.

Postoperative pain management remains an important clinical challenge in cardiothoracic surgery. Inadequate postoperative pain control may have adverse pathophysiologic sequelae, including increased myocardial oxygen demand, hypoventilation, suboptimal clearance of pulmonary secretions, acute respiratory failure, and decreased mobility, with associated increased risks for thromboembolic events. These adverse events may result in greater perioperative morbidity and mortality.

Despite several multimodal approaches to postoperative pain control, optimal pain management after cardiothoracic procedures remains elusive.

Regional anesthesia (RA) is often included in enhanced recovery protocols (ERPs) as an important component of a bundle of interventions to improve outcomes after surgery. Regional anesthesia techniques, including neuraxial and peripheral nerve block, can provide many benefits for patients in the perioperative period. These benefits include a decrease in postoperative pain (subsequently reducing opioid consumption and associated adverse effects), decrease in nausea and vomiting, improvement in mobilization and recovery of gastrointestinal function, decrease in length of stay (LOS), reduction in surgical stress response, and potentially, reduction in morbidity and mortality. They are therefore commonly used to improve quality of patient care and have also been used as a key component of many enhanced recovery protocols (ERPs).

The transversus thoracis muscle plane block (TTP) is a newly developed regional anesthesia technique which provides analgesia to the anterior chest wall. First described by Ueshima and Kitamura in 2015, the TTP block is a single-shot nerve block that deposits local anesthetic in the transversus thoracis muscle plane between the internal intercostal and transversus thoracis muscles. In the original ultrasound- guided cadaveric study, the TTP block was found to cover the T2-T6 intercostal nerves.

The anterior branches of these intercostal nerves dominate the sensory innervation of the internal mammary region, suggesting this new technique had potential to provide analgesia for surgery of the anterior chest wall.

Another technique for blocking multiple anterior branches of intercostal nerves, named the parasternal intercostal nerve block (PSI block). To perform a PSI block, we inject a local anesthetic between the pectoral major muscle and the external intercostal muscle. Because anterior branches of the intercostal nerve penetrate through these two muscles to innervate the internal mammary area, injection of a local anesthetic to this plane could block anterior branches of intercostal nerves.

Parasternal intercostal nerve blocks using local anesthetic agents have been shown to provide improved postoperative pain control and decreased opioid requirements with fewer potential complications.

This study can reduce economic cost by ENHANCED RECOVERY After Surgery (ERAS) (early extubation, reduce ICU and hospital stay) and improving postoperative analgesia. Implementation of such programs has resulted in patient and healthcare benefits, including promising early results within the cardiac surgical community.

Inclusion Criteria:

• Patient acceptance.
• Sex: both; male and female
• Age (21-60) years old.
• American society of anesthesiology (ASA): II and III.
• Body mass index (BMI) >35 kg/m2
• Elective cardiac surgeries requiring median sternotomy.
• Accepted mental state of the patient.
• Non-smoker or ex-smoker for more than one month.
• Optimal preoperative glycemic control, defined by a hemoglobin A1c level less than 6.5%.

Exclusion Criteria:

• Patient refusal and lack of informed consent.
• Emergency or non-median sternotomy surgery.
• History of allergy to local anesthetics (lidocaine or bupivicaine).
• Coexisting hematologic disorders or malnourished patient.
• Pre-existing major organ dysfunction including hepatic or renal failure, and left ventricular ejection fraction <30%
• Peripheral neuropathy.
• Pregnancy.
• Patients with a diagnosis of cognitive impairment.
• Significant psychiatric illnesses including schizophrenia, bipolar disorder, uncontrolled anxiety, or depression.