Assessment of phantom-based needling training in improving the performance of ultrasound-guided transversus abdominis plane (TAP) block by anaesthesia residents – A pre- and post-intervention study

INTRODUCTION The ultrasound (USG)-guided regional blocks require a triad of interconnected skills: image acquisition, anatomical interpretation and hand–eye coordination. These need not only lectures and demonstrations, but also the skill of good hand–eye coordination.[1] Phantom-based hands-on training can create an appropriate environment to develop the skills needed to perform USG-guided blocks. This study aimed to assess the effectiveness of phantom-based needling training in improving the performance of anaesthesia residents in USG-guided transversus abdominis plane (TAP) block compared to the conventional training method. The primary objective was to compare the total duration of time taken for the block performance before and after training in the phantom-based model. The secondary objectives were to compare the needle visibility score, the number of needle insertions and redirections, overall confidence and performance scores as measured by the Likert scale. METHODS This study was conducted at a tertiary care institute after getting Institutional Ethics Committee approval (vide approval number JIP/IEC/2019/484, dated 18th February 2020) and the trial registered at the Clinical Trials Registry - India (CTRI) (vide registration number CTRI/2021/05/033881, www.ctri.nic.in). The study was conducted from June 2021 to December 2021. Written informed consent was obtained from all individual participants for participation in the study and use of the data for research and educational purposes. The study was carried out in accordance with the 1964 principles of the Declaration of Helsinki and its later amendments or comparable ethical standards. Patients of the American Society of Anesthesiologists physical status (ASA-PS) I–III, aged 18–70 years and posted for elective abdominal surgeries requiring TAP block were included in the study. Parturients and patients with coagulation abnormalities, local abdominal wound infections or allergies to local anaesthetics were excluded. Residents underwent conventional training, including video-based lectures and live demonstrations over human volunteers using a high-frequency (15-6 MHz) linear probe. In addition, they had to demonstrate the sonoanatomy of the TAP needle insertion technique for proper image acquisition to the attending anaesthesiologist before proceeding with the block. The supervising anaesthesiologist documented the primary outcome, the total duration taken for completion of the block, which was the time noted from the time of needle insertion to deposition of local anaesthetic in TAP. They also noted the secondary outcomes, such as needle insertions and redirection, which are the number of times the resident inserts the needle and the number of times the resident redirects the needle after insertion without withdrawing the needle out, respectively. As assessed by the attending anaesthesiologists, the overall confidence score was noted on the Likert scale as follows: 1- strongly not confident, 2- not confident, 3- undecided, 4- confident and 5- strongly confident. In addition, the overall block performance score was noted on the Likert scale as follows: 1- excellent, 2- good, 3- fine, 4- bad and 5- very bad. Following conventional training, the residents underwent training using the phantom model (CAE Blue Phantom™ Regional Anaesthesia Ultrasound Training Block Model; ©CAE Healthcare Inc., Quebec, Canada) 20 min a day for one week. During the end of the training period, the residents were expected to demonstrate the USG-guided needling technique with adequate needle visibility. They were allowed to perform a block in patients under the guidance of a supervising anaesthesiologist, and all of the parameters related to the block performance were reassessed and documented. Based on a previous study, the mean ± standard deviation (SD) block performance time was 6.8 ± 4.1 min. After simulation training, assuming a 40% decrease in procedure time, which was 4.1 ± 2.8 min, with an alpha of 5% and power of 80%, the minimum required sample size was 15.[2.3] It was calculated using the nMaster version 2.0. The data were collected using Statistical Package for the Social Sciences (SPSS) version 20.0. (International Business Machines Corporation, Armonk, New York, United States). Continuous variables like age and duration of nerve block were summarised as mean ± SD or median (interquartile range [IQR]) based on the type of distribution. Categorical variables were summarised as frequency and proportion. The normality was performed using the Shapiro–Wilk test and the association between study groups and the outcome variables was found using the Mann–Whitney U test. RESULTS Fifteen residents and 30 patients undergoing elective abdominal surgery were recruited for the study. The duration, number of needle insertions and redirections, needle visibility score, performance score and confidence score are expressed as median (IQR) [Table 1].Table 1: Study parameters in the two groupsThere was a significant decrease in the duration of performance of the block in the postintervention group compared to the preintervention group (P value < 0.001). There was also a significant difference in needle visibility, number of attempts and improvement in the performance and confidence scores. DISCUSSION We observed a decrease in the total time taken to perform the USG-guided TAP block after phantom-based training. A decrease in the number of needle insertions following training, a improvement in the needle visibility and performance scores was observed following training in the phantom model. The study also revealed that phantom-based training improved the residents’ confidence scores. In a study by Vial et al.[2] involving anaesthesiology residents performing TAP blocks, it was found that the duration of block and number of needle repositions were significantly reduced after performing 20 procedures compared to the beginning of the training. In another study, Kwon et al.[4] used a gelatin-based phantom model to improve the skill of cervical plexus block for the participants allocated to the training and control groups. The time was significantly reduced, and the performance score was significantly higher in the training group compared to the control group. In a similar study on novice anaesthesia residents using a porcine model for USG-guided TAP block, Park et al.[5] found that the performance, level of comfort and confidence score based on the Likert scale significantly improved in the post-training period compared to the pretraining period. A systematic review of USG-guided regional nerve block simulation, which included 12 studies by Chen et al., also signified the importance of simulation-enhanced training compared to non-simulated training.[6] Our study has some limitations. It was a pre - and post-intervention comparison study, not a randomised controlled trial. The difference in the previous experience of the residents in performing the block could have also influenced the result. Inadequate sample size is also another area for improvement. CONCLUSION The phantom-based training of anaesthesiology residents significantly decreased USG-guided TAP block performance duration. It also significantly improved needle visibility and confidence scores among anaesthesiology residents. Financial support and sponsorship This research was supported by intramural funding of the institute (Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India). Conflicts of interest There are no conflicts of interest. Study data availability De-identified data may be requested with reasonable justification from the authors (email to the corresponding author) and shall be shared after approval as per Authors’ Institution policy.

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