Clinical trial NCT04596163: Transversus Thoracis Muscle Plane Block for Sternotomy Pain in Cardiac Surgery
Official title: Transversus Thoracis Muscle Plane Block for Acute and Chronic Pain Management in Cardiac Surgical Patients Requiring Sternotomy: a Prospective Randomized Controlled Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Pain, Postoperative
Surgical Wound
Cardiac Event
Keywords: Regional anaesthesia
Cardiac surgery
Lead sponsor: Chinese University of Hong Kong
Sponsor class: OTHER
First posted: 2020-10-22
Enrollment: 86
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Single-centred, double-blinded, randomized, placebo-controlled trial
Primary purpose: TREATMENT

Brief summary: Sternotomy pain is usually significant after cardiac surgery. Analgesic options for sternotomy in cardiac surgery are often limited. Poorly controlled acute pain is an important factor to development of chronic postsurgical pain. The transversus thoracis muscle plane (TTP) block is a novel technique that provides analgesia to anterior chest wall. A double-blinded RCT is conducted to assess the efficacy of applying TTP block as an adjunct to analgesia in cardiac surgery.

Detailed description: Chronic postsurgical pain (CPSP) is defined as the persistence of pain at surgical site or referred area, at least 3 months following the surgical procedure. CPSP after median sternotomy is not uncommon after cardiac surgery. The reported incidence ranges from 28% to 56% up to 2 years postoperatively. A number of factors can contribute to the variation in incidence, including the variations in presentation of chronic post-sternotomy pain and under-reporting from patients. Given the nature of cardiac surgery and considerable anxiety of patients at perioperative period, patients would tend to live with the chronic pain and rationalize it as a normal consequence of the surgery. Patients therefore may not report any symptoms, resulting in a delay in diagnosis of chronic post-sternotomy pain.

The mechanisms for development of CPSP after sternotomy are not fully known. The up-regulation, activation and neural sensitization during the acute pain phase are important factors to the development of chronic pain. Causes of pain from sternotomy include neuropathy from anterior intercostal nerves entrapment or injury during surgical dissection and internal mammary artery harvesting, musculoskeletal injury from surgical incision and dissection, sternal fracture or incomplete bone healing, and development of sternal wound infections. Poorly controlled acute pain in the perioperative period can trigger central sensitization, a stepwise modification of spinal pain pathways involving protein synthesis and synaptic strength, which can lead to hyperalgesia and chronic pain. Therefore, good perioperative acute pain control not only provides postoperative pain relief, but also prevents occurrence of chronic pain.

In most centres, opioids such as fentanyl and morphine are used mainly for the management of acute pain after cardiac surgery. However, perioperative opioids are known to be associated with dose-dependent side effects such as nausea and vomiting, pruritis, respiratory depression, postoperative chronic opioid use and increased risk of chronic pain. Multimodal approach such as the use of NSAIDs may not be optimal after cardiac surgery due to the risk of bleeding and renal failure. Regional analgesia has opioid-sparing effect and seems to be a good choice for perioperative anaglesia. Regional techniques such as thoracic epidural and paravertebral blocks have been described but they are not ideal due to the potential complications from systemic heparinization in cardiac surgery. Erector spinae plane (ESP) block was reported to decrease perioperative morphine consumption and early postoperative pain score. However, the transverse process tip is not always easy to visualize on ultrasound, especially in obese patients, resulting in variation in ESP block efficacy.

Transversus thoracis muscle plane (TTP) block covers the anterior branches of intercostal nerves T2 to T6. It has been described in cardiac surgical patients that provides analgesia for sternotomy. TTP block is a superficial block and therefore is relatively safe when compared with thoracic epidural and paravertebral nerve block during heparinization. The investigators hypothesized that pre-emptive TTP block can provide effective perioperative analgesia and prevent the occurrence of CPSP in cardiac surgical patients requiring median sternotomy. A prospective, double-blinded randomized controlled trial was conducted to assess the analgesic efficacy of TTP block in open cardiac surgery.

Eligibility criteria: Inclusion Criteria:

* Elective CABG, aortic valve repair/replacement, mitral valve repair/replacement, or combined CABG/valve procedure

Exclusion Criteria:

* emergency surgery
* redo surgery
* history of thoracotomy or mastectomy
* history of chronic pain or regular analgesic use (except paracetamol and NSAID)
* history of psychiatric illnesses or illicit drug use
* renal failure with eGFR \<30ml/min or on renal replacement therapy
* mortality or require re-sternotomy within 24h after operation
* intraoperative use of remifentanil
* unable to provide informed consent

Primary outcomes:
measure: Opioid consumption
timeFrame: Once at the end of the surgery
Secondary outcomes:
measure: Percentage blood pressure change
timeFrame: From 5 minutes before skin incision to 10 minutes after skin incision at 1 minute interval ( a total of 15 time point)
measure: Percentage heart rate change
timeFrame: From 5 minutes before incision to 10 minutes after skin incision at 1 minute interval (a total of 15 time points)
measure: Morphine consumption
timeFrame: up to 72 hours postoperatively
measure: Length of hospital stay
timeFrame: Immediately after the surgery up to the day of patient discharge
measure: Intensive Care unit (ICU) stay
timeFrame: Immediately after the surgery up to the time of ICU discharge
measure: Pain score
timeFrame: At 8, 12, 24, 48 and 72 hours after TTP block and on day 7 after surgery (6 time points).
measure: Peak expiratory flow rate
timeFrame: Once as baseline on the day before operation and at 6 time points after surgery (ie. at 8, 12, 24, 48, 72 hours after block and on day 7 after surgery).
measure: Forced expiratory volume in 1 second
timeFrame: Once as baseline on the day before operation and at 6 time points after surgery (ie. at 8, 12, 24, 48, 72 hours after block and on day 7 after surgery).
measure: Brief Pain Interference Scale
timeFrame: at 3-month and 6-month after surgery
measure: Pain Catastrophizing Scale
timeFrame: at 3-month and 6-month after surgery
Other outcomes:
Locations:
city: Hong Kong
country: Hong Kong
facility: Prince of Wales Hospital
Study officials:
affiliation: Chinese University of Hong Kong
name: Henry Man Kin Wong, MBChB
role: PRINCIPAL_INVESTIGATOR
References: