Comparative Study of the Efficacy and Safety of Ultrasound-guided and Landmark-based Paravertebral Block Technique in Patients undergoing Elective Unilateral Breast Surgery

Abstract

Introduction: Identifying the Paravertebral Space (PVS) by its anatomical landmarks is associated with high failure rates and complications. With the advent of Ultrasonography (USG), failure rate has decreased leading to an increased interest in performing USG-guided Thoracic Paravertebral Block (TPVB). Aim: To assess the efficacy and safety of ultrasound guided TPVB and its comparison with the landmark-based technique, in patients undergoing elective unilateral breast surgery. Materials and Methods: This cross-sectional study was carried out at Command Hospital, Pune from July 2014 to December 2015, on females between 18-70 years, accepted in American Society of Anaesthesiology (ASA) I-III for unilateral breast surgeries. Patients were divided into two groups with 40 subjects in each group. Group A subjects were treated with anatomical landmark technique and group B subjects with Ultrasound-guided (USG-guided) technique. The p-value 0.05 using Fisher’s-Exact test). Mean (SD) time taken for performing the block in group A was 371.10 (10.37) seconds while it was 613.73 (37.15) seconds in group B (p-value <0.05 by two independent sample t-tests). No statistically significant difference was seen in haemodynamic parameters, except for the Heart Rate (HR) at 70, 80, 90 minutes after administering the block and at the end of surgery. Correlation analysis for quantitative variables with PVS depth (dependent variable), measured sonologically, showed very good linear correlation of PVS depth with weight (Pearson’s correlation coefficient, r=0.819, p-value <0.001). BMI (r=0.884; p-value <0.001). Conclusion: The success rate is higher with ultrasound-guided TPVB compared to the landmark technique, though statistically insignificant. But it is recommended to use ultrasound-guided TPVB for advantages such as lesser requirement of opioid supplementation, real time visualisation of the spread of drugs in PVS with lesser complication rates.

Keywords

• anatomic landmark
• heart rate
• paravertebral
• thoracic
• ultrasonography