Bilateral Thoracic Paravertebral Blocks in Obese and Non-obese Patients Undergoing Reduction Mammaplasty

Study Overview
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Brief Summary
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Aim: Although regional anesthesia (RA) techniques are advantageous in the anesthetic management of obese patients (body mass index (BMI)≥30); their performances can still be associated with technical difficulties and greater failure rates. The aim of this study is to compare the performance properties and analgesic efficacy of ultrasound (US)-guided bilateral thoracic paravertebral blocks (TPVBs) in obese and non-obese patients. Material methods: After obtaining ethics committee approval; data of 82 patients, who underwent elective bilateral reduction mammaplasty under general anesthesia with adjunctive TPVB analgesia between December of 2016 and February of 2020, were reviewed. Patients were allocated into two groups with respect to their BMI scores (Group NO: BMI<30 and Group O: BMI≥30). Demographics, TPVB ideal US image visualization and performance times, needle tip visualisation and TPVB performance difficulties, number of needle maneuvers, surgical, anesthetic and analgesic follow-up parameters, incidence of postoperative nausea vomiting (PONV), sleep duration, length of postanesthesia care unit (PACU) and hospital stay, patient and surgeon satisfaction scores were all investigated and compared.

Detailed Description
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Aim: The number of obese patients (body mass index (BMI)≥30) has increased dramatically worldwide, and we, as anesthesiologists, routinely come up against them in our daily clinical practice. Although the preference of various peripheral and neuroaxial regional anesthesia (RA) techniques seems to be advantageous in the anesthetic management of these patients, their performances can also be associated with technical difficulties and greater failure rates. The aim of this study is to compare the performance properties and analgesic efficacy of ultrasound (US)-guided thoracic paravertebral blocks (TPVBs) in obese and non-obese patients. Material methods: After obtaining ethics committee approval; data of 82 patients, who underwent elective bilateral reduction mammaplasty under general anesthesia with adjunctive TPVB analgesia between December of 2016 and February of 2020, were reviewed. Patients were allocated into two groups with respect to their BMI scores (Group NO: BMI<30 and Group O: BMI≥30). Demographics, TPVB ideal US image visualization and performance times, needle tip visualisation and TPVB performance difficulties, number of needle maneuvers, surgical, anesthetic and analgesic follow-up parameters, incidence of postoperative nausea vomiting (PONV), sleep duration, length of postanesthesia care unit (PACU) and hospital stay, patient and surgeon satisfaction scores were all investigated and compared. Student's t, Mann-Whitney-U and Chi-square tests were used for statistical analysis.

Official Title
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The Performance Properties and Efficacy of Ultrasound-Guided Bilateral Thoracic Paravertebral Blocks in Obese and Non-obese Patients Undergoing Reduction Mammaplasty: A Historical Cohort Study

Conditions
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Pain, Postoperative, Obesity, Thoracic Paravertebral Blocks, Ultrasound, Performance

Intervention / Treatment
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* Procedure: Bilateral Thoracic paravertebral block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists (ASA) physical status of 1-3 Capable of consenting Capable of understanding the instructions for using the NRS pain scores Capable of replying the questions Lack of contraindications to regional anesthesia (allergy to a LA, local infection, and coagulopathy) and especially TPVB Absence of mental/psychiatric disorders Absence of chronic analgesic/opioid use Absence of alcohol/illicit drug use Exclusion Criteria: Patient refusal of RA/TPVB performance American Society of Anesthesiologists (ASA) physical status of 4 Not capable of consenting Not capable of understanding the instructions for using the NRS pain scores Not capable of replying the questions Contraindications to regional anesthesia (allergy to a LA, local infection, and coagulopathy) and especially TPVB Presence of mental/psychiatric disorders Presence of chronic analgesic/opioid use Presence of alcohol/illicit drug use

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Non-Obese Patients (Group NO: body mass index (BMI) <30)<br>Patients received bilateral single injection ultrasound (US)-guided bilateral thoracic paravertebral block (TPVB) at the level of T3-T4 with 20 mL bupivacaine 0.375% per injection/side. | Procedure: Bilateral Thoracic paravertebral block<br>* The blocks were performed at the T3-T4 level bilaterally to block the dermatomes between the T2 and T6 levels (breast innervation area).<br>* Other names: TPVBs;|
| Obese Patients (Group O: body mass index (BMI) ≥30)<br>Patients received bilateral single injection ultrasound (US)-guided bilateral thoracic paravertebral block (TPVB) at the level of T3-T4 with 20 mL bupivacaine 0.375% per injection/side. | Procedure: Bilateral Thoracic paravertebral block<br>* The blocks were performed at the T3-T4 level bilaterally to block the dermatomes between the T2 and T6 levels (breast innervation area).<br>* Other names: TPVBs;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thoracic paravertebral block (TPVB) performance time | Time period between the US probe placement to the right side at T3-T4 level and the needle withdrawal from the left side T3-T4 level | 0-20 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative numeric rating scale (NRS) pain scores | NRS pain scores (0: no pain, 10: worst pain imaginable) through postoperative first 24 hours | 0-24 hours | 
| Ideal US image visualization time | Time period between the US probe placement at T3-T4 level and visualizing the ideal image to perform the block | 0-5 minutes | 
| Difficulty of needle tip visualization | Likert scale: 1-5 (1:very poor, 5:very good) | 0-20 minutes | 
| Number of needle maneuvers to reach the paravertebral space | Number of needle maneuvers to reach the paravertebral space (PVS) | 0-20 minutes | 
| Requirement of additional maneuver due to insufficient local anesthetic spread | Requirement of additional needle maneuver due to insufficient local anesthetic (LA) spread | 0-20 minutes | 
| Difficulty of TPVB according to the anesthesiologists | Likert scale: 1-5 (1:very poor, 5:very good) | 0-20 minutes | 
| Length of stay in postoanesthesia care unit (PACU) | Modified Aldrete Scoring system (≥9/10) | 0-1 hours | 
| Number of patients required fentanyl intraoperatively | If a ≥ 20% increase above preinduction values in MAP or HR was observed during the perioperative period, additional fentanyl dose (1 μg/kg) was applied intravenously. | Intraoperative 2-6 hours | 
| Time to postoperative first pain | Postoperative first pain description (NRS ≥4) until discharge | 0-48 hours | 
| Number of paracetamol requirement through the postoperative first 24 hours | Paracetamol was used when postoperative pain NRS ≥4 in the postanesthesia care unit or on the wards (on postoperative day 1) | 0-24 hours | 
| Number of tramadol requirement through the postoperative first 24 hours | Tramadol was used when postoperative pain NRS ≥4 again after 1 hour of paracetamol application in the postanesthesia care unit or on the wards (on postoperative day 1) | 0-24 hours | 
| Incidence of PONV through the postoperative first 24 hours | Number of feeling nausea or vomiting | 0-24 hours | 
| Duration of sleep through the postoperative first 24 hours | Total hours of sleep at first night | 0-24 hours | 
| Length of hospital stay | Post Anaesthetic Discharge Scoring System (PADSS) (≥9/10) | 0-48 hours | 
| Patient satisfaction | Satisfaction score during hospital discharge: 0: very unsatisfied, 3: very satisfied | 0-48 hours | 
| Surgeon satisfaction | Satisfaction score during hospital discharge: 0: very unsatisfied, 3: very satisfied | 0-48 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obesity, Thoracic paravertebral blocks, Ultrasound-guidance, Performance difficulty, Satisfaction