Comparison of Ultrasound-Guided Erector Spinae Plane Block and Transversus Abdominis Plane Block in Acute Pain Management after Colectomy in Colon Cancer Patients: A Randomized Controlled Clinical Trial

Faculty Development Competitive Research Grant Program 2021-2023

The purpose of the Project
Our hypothesis
Erector spinae plane block (ESP block) will provide superior analgesia compared to transverses abdominis plane block (TAP block) in patients undergoing colectomy due to colon cancer (3-rd stage).
Objectives
The primary objective of this study is compare ESP block and TAP block for postoperative analgesia in patients who have undergone colectomy.
Secondary objectives will be:
1.Incidences of the following side effects:
a)Postoperative nausea and vomiting (PONV);
b)Respiratory depression;
c)Local anesthetic toxicity;
2.Total opioid consumption in postoperative period in hospital (from the end of surgery up to 24 hours after the end of surgery);
3. Sensory blockade assessment;
4.Quality of sleep (Pittsburgh Sleep Quality index)
5.Physiological parameters (blood pressure, pulse, arterial oxygen saturation) during first 24 hours while the patient is in ICU.
6. Overall patient satisfaction at discharge (short assessment of patient satisfaction);
7.Postoperative cognitive dysfunction;
8.Postoperative delirium;
9. Average pain scores, persistent surgical site pain and analgesic drug use at 1 month postoperatively;
Research methods
This prospective, double-blinded, randomized, controlled study will be conducted in the department of anesthesiology and intensive care of National Research Oncology Center.
Ethics
Each patient will sign an informed consent form for block interventions and participation in the study.

Inclusion Criteria:
1.Male and Female patients aged 18-70 years - body mass index less 35 kg/m2
2. Elective colectomy (laparotomic approach) due to colon cancer (stage III).
3. American Society of Anesthesiologists physical status class I - III
4. Signed informed consent;
The exclusion criteria
1. Presence of coagulation disorder;
2. Infection at the injection site of the block;
3. Known allergy to local anesthetics;
4. Advanced hepatic or renal failure;
5. Chronic opioid consumption;
6. Body mass index (BMI) ≥ 35 kg m−2;
Patient randomization
Patients will be randomly allocated into two groups based on a randomization table created by a researcher who will be not involved in the study. For each randomized patient, the anesthesiologist will take the corresponding sealed envelope from a folder, indicating the treatment to be assigned to the patient.
Blinding
All investigators, staff, and patients will be blinded to the treatment groups. The study medication will be prepared by an anesthesiologist who is not involved in the study or in the care of the patient. Both solutions and syringes will appear identical. Unless medically indicated, unmasking will occur only after statistical analysis has been completed.
Sample size calculation
Single shot ESPB could achieve the mean postoperative pain score of 1 to 3 points on the NRS (ESP block group) and patient receiving TAP block reach the pain intensity of approximately 2-4 points on the NRS. We consider a reduction in mean pain scores by 1 point to be clinically meaningful. Therefore, we decided to set the sample size at 50 per group.
Anesthesia
In the operating room (OR), a standard monitoring with electrocardiography, non-invasive blood pressure, peripheral oxygen saturation and bi-spectral index monitoring will be applied to all patients. After the placement of a 22-gauge intravenous line, a 15 mL kg−1 isotonic saline infusion was started. The anesthesiologists will perform anesthesia inductions with intravenous propofol 2–3 mg kg−1, fentanyl 1 μg kg−1 and rocuronium bromide 0.6 mg kg−1, and when the patients' BIS scores decreased to 40–60, endotracheal intubation will be performed. Maintenance of anesthesia will be provided with total intravenous anesthesia: propofol I.V., low-dose ketamine infusion, fentanyl.
Study interventions
Following intubation, patients in the first group (ESP) will be placed in the lateral decubitus position. The anesthesiologist will place the ultrasound probe in longitudinal orientation at the level of the T7 spinous process and then move the probe 3 cm laterally from the midline. The ultrasound landmarks, which included the T7 transverse process and the overlying erector spinae muscle, will be identified. Under aseptic conditions, a 80-mm 21-gauge block needle (Stimuplex(R) B-Braun medical, Melsungen, Germany) will be inserted in-plane at an angle of 30–40° in cranial-to-caudal direction until the tip contacted the T7 transverse process. After hydro-dissection with 2–3 mL of isotonic saline solution anesthesiologist will confirm the correct needle tip position, then the anesthesiologist will inject 20 mL of 0.375% ropivacaine deep to the erector spinae muscle. The same procedure will be repeated with 20 mL of 0.375% ropivacaine solution on the contralateral side. In the second group, patients will receive ultrasound–guided bilateral TAP block. We will use 40 mL (20 mL for left and 20 mL for right side) of 0.375% ropivacaine (Astra-Zeneca AB, Sweden) for injection into the transversus abdominis plane under ultrasound guidance).
The probe will be positioned across the posterior axillary area, and 3 typical abdominal wall muscles will be identified. The needle will be directed in plane from anterolateral side to posteromedial side followed by a negative aspiration test with 2 ml normal saline to confirm the position. Next, 20 ml 0.375% ropivacaine will be injected on each side between the posterior junction of transversus abdominous muscle and the anterolateral border of quadratus lumborum. The contralateral block will be performed using the same technique.
Outcomes
Primary outcome and measurement
The primary outcome of this study will be to compare the resting pain scores after initial stabilization. The pain will be assessed at 4,8,16, 48 and 72 hours after surgery (end of surgery).
Pain scores will be measured using the patient-reported numeric rating scale (NRS), where 0 is no pain and 10 the worst pain imaginable.
Secondary outcomes and measurement
The following secondary outcomes will be collected during the in-hospital stay and follow-up of study patients:
1.Total opioid consumption in hospital (until discharge): (morphine equivalent dosage) for analysis will be measured (from the end of surgery up to 24 hours).
2. Incidence post-operative complications:
a) Moderate to severe PONV will be collected and assessed using PONV Score : 1 to 3 (1- No nausea, 2- Nausea, 3- Vomiting) PONV Score (3 points).
b) Incidence of respiratory depression will be assessed by continuous monitoring of SpO2;
c)Local anesthetic toxicity will be diagnosed based on clinical symptoms and signs.
3. Sensory assessment will be performed a trained nurse.
4.Quality of sleep (Pittsburgh Sleep Quality index)
5.Physiological parameters (blood pressure, pulse, arterial oxygen saturation) during first 24 hours while the patient is in ICU.
6. Overall patient satisfaction at discharge (using a 7-item Likert scale)
7.Postoperative cognitive dysfunction ( will be assessed at 4. 8,16, 24, 48, 72 hours)
8.Postoperative delirium ( will be checked at 4, 8,16, 24, 48, 72 hours)
Ramsay Sedation Scale (RSS) 1 to 6 (1- Awake and Agitated, 2- Awake but calm to 6- Asleep and no response to loud auditory stimulus Sedation score of patients: Ramsay Sedation Scale (6 points).
a)Awake; agitated or restless or both.
b)Awake; cooperative, oriented, and tranquil.
c)Awake; but responds to commands only.
d)Asleep; brisk response to light glabellar tap or loud auditory stimulus.
e)Asleep; sluggish response to light glabellar tap or loud auditory stimulus.
f)Asleep; no response to glabellar tap or loud auditory stimulus.
9. Average pain scores, persistent surgical site pain and opioid use at 1 month postoperatively; (Patients will be contacted by telephone at 1 month to assess the presence of pain (NRS 0-10), use of analgesics)
Evaluation of pain
The NRS will be used for the assessment of postoperative pain in both groups. The NRS is a scale consisting of integers from 0 through 10; 0 means ‘no pain’ and 10 means ‘worst pain imaginable’.
Postoperative analgesia
At the end of the surgery, an intravenous patient-controlled analgesia (PCA) device will be used for postoperative analgesia. The PCA device will administer 10 mg tramadol as a bolus dose with a 20-minute lock-time and no basal infusion. When the NRS scores were ≥ 6 while coughing, patients will receive intravenous morphine (4 mg) as a rescue analgesic.
Total tramadol consumption at the postoperative 24th hour, intraoperative fentanyl, NRS scores at each time-point, total rescue analgesic consumption in the first 24 postoperative hours, and the incidence of complications were recorded.