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

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

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.

Study Overview

• Status: Completed
• Conditions: Obesity; Pain, Postoperative; Performance; Ultrasound; Thoracic Paravertebral Blocks
• Intervention / Treatment: Procedure: Bilateral Thoracic paravertebral block

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 82

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

• Sampling Method: Non-Probability Sample

Study Population

Patients (obese and non-obese) required reduction mammoplasty surgery and received general anesthesia with TPVB analgesia

Description

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

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Non-Obese Patients (Group NO: body mass index (BMI) <30); 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; The blocks were performed at the T3-T4 level bilaterally to block the dermatomes between the T2 and T6 levels (breast innervation area).; Other Names: TPVBs
Obese Patients (Group O: body mass index (BMI) ≥30); 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; The blocks were performed at the T3-T4 level bilaterally to block the dermatomes between the T2 and T6 levels (breast innervation area).; Other Names: TPVBs

What is the study measuring?

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
Length of hospital stay	Post Anaesthetic Discharge Scoring System (PADSS) (≥9/10)	0-48 hours
Length of stay in postoanesthesia care unit (PACU)	Modified Aldrete Scoring system (≥9/10)	0-1 hours
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
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
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

Collaborators and Investigators

• Sponsor: Istanbul University
• Investigators: Principal Investigator: Emine A Salviz, Assoc Prof, Study Principal Investigator

Publications and helpful links

General Publications

• Kilicaslan A, Topal A, Erol A, Borazan H, Bilge O, Otelcioglu S. Ultrasound-guided multiple peripheral nerve blocks in a superobese patient. Case Rep Anesthesiol. 2014;2014:896914. doi: 10.1155/2014/896914. Epub 2014 Jan 22.
• Franco CD, Gloss FJ, Voronov G, Tyler SG, Stojiljkovic LS. Supraclavicular block in the obese population: an analysis of 2020 blocks. Anesth Analg. 2006 Apr;102(4):1252-4. doi: 10.1213/01.ane.0000198341.53062.a2.
• Kula AO, Riess ML, Ellinas EH. Increasing body mass index predicts increasing difficulty, failure rate, and time to discovery of failure of epidural anesthesia in laboring patients. J Clin Anesth. 2017 Feb;37:154-158. doi: 10.1016/j.jclinane.2016.11.010. Epub 2017 Jan 10.

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2016
• Primary Completion (Actual): February 28, 2020
• Study Completion (Actual): February 28, 2020

Study Registration Dates

• First Submitted: October 18, 2020
• First Submitted That Met QC Criteria: October 18, 2020
• First Posted (Actual): October 22, 2020

Study Record Updates

• Last Update Posted (Actual): October 22, 2020
• Last Update Submitted That Met QC Criteria: October 18, 2020
• Last Verified: October 1, 2020

More Information

Terms related to this study

• Keywords: Obesity; Satisfaction; Thoracic paravertebral blocks; Ultrasound-guidance; Performance difficulty
• Additional Relevant MeSH Terms: Pathologic Processes; Postoperative Complications; Pain; Neurologic Manifestations; Pain, Postoperative
• Other Study ID Numbers: 2020/964

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No