Comparison of USG guided with Anatomical Landmark guided TAP Block following Total Abdominal Hysterectomy

Introduction

Most surgical patients frequently experience soreness following their surgery. Effective pain management is essential for the patient to begin normal activities earlier and prevents severe physiological and psychological effects that could arise from uncontrolled postoperative pain. The main goals of postsurgical pain relief are to mitigate the adverse effects of acute pain after surgery and enable a smoother return to normal functioning.¹ Opioid analgesic medications have been used as the mainstay of postoperative pain treatment. There is an increasing need for research into pain management techniques which employ a multimodal strategy, given the recent increase in fatalities and morbidity related to opioid addiction.²

The Transversus Abdominis Plane (TAP) block is a component of a comprehensive anaesthetic approach intended to provide both visceral and somatic analgesia and expedite recovery from lower abdominal procedures. Anatomical landmarks like the Triangle of Petit or ultrasound guidance can be utilized for delivering the TAP block.³ The duration of postoperative pain relief can be extended by combining local anaesthetics such as bupivacaine with adjuvants like the opioid agonist-antagonist Nalbuphine.⁴ Compared to the anatomical landmark technique employing the Triangle of Petit, ultrasound guidance for the TAP block ensures a quicker onset of action, lowers the chance of failures, requires a lesser volume of drug, and prolongs the duration of effect.⁵

To evaluate the comparative efficacy of anatomical landmark technique and ultrasound-guided TAP block in terms of postoperative analgesic effects following total abdominal hysterectomy, this study will use injections of 0.25% Bupivacaine along with 10 mg Nalbuphine to make an overall volume of 20 ml on each side. The period of analgesia is the primary outcome measure. The duration of sensory block, variations in hemodynamic parameters, the frequency of block failures, the time to administer the first rescue analgesics, and adverse effects will constitute secondary outcomes.

Methods

The research will be conducted in the JNMC Department of Anaesthesiology, Datta Meghe Institute of Higher Education & Research, Sawangi (M), Wardha. The DMIHER Institutional Ethics Committee has granted approval for the research [Ref.No. DMIHER (DU)/IEC/2023/888] on 31^st March, 2023. We shall obtain the participants’ signed informed consent before the commencement of the study. A departmental steering group will also supervise and track the study’s advancement until its completion.

Research design – Prospective, comparative design.

Study area – Department of Anaesthesiology JNMC & AVBRH.

Study period – 2 years

Patient allotment – Computer-generated randomization.

Study population – Patients undergoing Total Abdominal Hysterectomy surgeries.

Methods

A pre-operative evaluation will be performed on each patient one day preceding the surgery. Relevant patient data, such as demographics, medical history, current symptoms, and a thorough physical examination, will be requested. Appropriate laboratory tests and blood tests will be ordered. The study’s goals, advantages, and possible disadvantages will be explained to the patients. Each patient who wishes to participate in the study must provide written informed consent. Prior to surgery, patients have to follow a minimum eight-hour fasting period. An electrocardiography (ECG), blood pressure monitor, and an oxygen saturation probe will be affixed to the patient on the day of the surgery and baseline vital parameters will be constantly monitored. After securing an 18-gauge intravenous (IV) line, 10 to 15 millilitres of Ringer lactate solution will be injected intravenously per kilogram. A 75–100 mcg/kg injection of ondansetron will be injected intravenously ten minutes before the anaesthetic procedure. The patients will be administered spinal anaesthesia under strict aseptic precautions at L3-L4 interspace. After the abdomen is closed following the total abdominal hysterectomy performed under a subarachnoid block with 3.5 millilitres of 0.5% bupivacaine, the TAP block will be administered based on the study groups to which the patient belongs. If the patient is conscious, lignocaine will be used to anaesthetize their skin before a 21-gauge block needle will be inserted to identify the TAP compartment via the Triangle of Petit or sonographically utilizing an ultrasound probe.

In both techniques, the transversus abdominis and rectus abdominis muscles will separate as the drug is administered, allowing the TAP compartment to be dissected.⁷ Postoperative pain reduction will be achieved with the prompt administration of the TAP Block following the surgical operation.⁸ Primary parameters deciding the efficacy of the procedure such as the hemodynamic parameters, time taken for the drug to act, cost-effectiveness, effectiveness of the block whether partial or total block, patient satisfaction etc. will be noted down and data analysis will be done. It is noteworthy that the TAP Block covers a non-dermatomal field. We will take note of the following information - The sensory blockade, level of sedation, postoperative pain relief measured by the visual analogue scale, timing of administration of rescue analgesia, and adverse effects. Patients will be moved to the monitoring ward after the surgery, where they will be observed every 10 minutes, 20 minutes, 30 minutes, 60 minutes, 120 minutes, 150 minutes and 180 minutes after the procedure. In the event that a patient is in severe pain, rescue analgesics will be given. When the patient’s pain level, as measured by the Visual Analogue Scale (VAS), reaches four or above, intravenous paracetamol will be administered at a dosage of 15-20 mg per kilogram. In the ultrasound-guided procedure, drug deposition is visualized, and in the anatomical landmark technique, medication flows freely from the needle, confirming the sensory block. The time it takes the patient to request their first dosage of rescue analgesia can be used to estimate the duration of the sensory blockade. The Ramsay Modified Sedation score will assess the degree of sedation during the TAP block and 30 and 60 minutes after it is administered. Following surgery, the patient’s sedation score will be assessed every ten minutes for a maximum of 180 minutes and whenever the patient feels pain.

Discussion

TAP Block is a non-dermatomal field block used to provide relief from both visceral and somatic pain by blocking the nerve inputs from the thoracolumbar spinal nerve plexus, including the intercostal nerves, subcostal nerves, ilioinguinal, and iliohypogastric nerves.⁹ In research comparing the efficacy of the USG-guided TAP block to the Anatomical landmark technique for postsurgical analgesia after total abdominal hysterectomy, the USG-guided approach produced better outcomes than the Anatomical landmark technique. The study used 0.25% Bupivacaine and 10mg Nalbuphine, with a volume of twenty ml on each side (bilateral). It demonstrated fewer failures, needed less medication, had a quicker onset of pharmacological effect, and had a longer half-life. By attaching to kappa receptors in the central nervous system, Nalbuphine inhibits the release of pain-related neurotransmitters such as substance P. It also functions as a partial agonist or antagonist at mu receptors and a competitive opioid agonist at kappa receptors. It is an adjuvant to bupivacaine, an amide local anaesthetic that lowers sodium permeability and raises the action potential threshold to impede nerve impulse conduction. Nalbuphine improved the effectiveness of TAP Block and offered better pain management without changing the patients’ hemodynamic profile. The interval between an injection and a Visual Analogue Scale (VAS) score of less than four was used to measure adequate analgesia. As a prior study has shown, there were no incidences of respiratory depression, drowsiness, nausea, pruritus, or vomiting—all commonly linked to mu receptor activity. Moreover, neither of the two evaluated procedures indicated dermatomal involvement in our investigation.

Patients receiving USG-guided TAP block had considerably low discomfort at rest, with lower VAS scores at four, twelve, and twenty-four hours, and a decreased need for postoperative morphine within the first 24 hours, according to a study comparing USG-guided with blind TAP block in hernia patients.¹⁰ The time to request the first dose of analgesic post surgery was prolonged in the group receiving the USG-guided hernia block (7.22 hours) than in the group receiving the landmark-guided TAP block (6.80 hours) in another study comparing the two procedures.¹¹

It was demonstrated in a meticulously executed double-blinded, randomized controlled clinical trial that the addition of twenty milligrams of Nalbuphine in a supraclavicular brachial plexus block with bupivacaine considerably prolonged the length of the motor and sensory blocks, and the period of analgesia.¹²

The research results will highlight the benefits of ultrasound-guided TAP blocks, especially when paired with bupivacaine and Nalbuphine for patients with total abdominal hysterectomy. The findings might prove this method is safe, effective, and linked to extended pain relief, decreased need for opioids, and few adverse effects. This work will add to the increasing amount of data that shows TAP Blocks can be a practical part of multimodal postoperative pain treatment plans.