Using a Flipped Classroom to Compare 2 Ultrasonography Operating Methods to Improve Practice in Ultrasound Detection Acupuncture

Abstract

Objective:

Ultrasound (US) detection acupuncture (UDA) is an innovative acupuncture technique that uses ultrasonography (USG) to detect the depth of the lung before performing acupuncture on the points around the chest to avoid puncturing the lungs. For acupuncturists to use UDA appropriately, it is crucial to have a good operating method to identify the pleura with USG. This study compared 2 US operating methods through active learning in a “flipped classroom” setting for acupuncture students.

Materials and Methods:

Students and interns were recruited to complete the UDA flipped classroom course and evaluate the operations of 2 US methods on either of 2 simulation models: (1) a single B-mode or (2) a combined M-mode + B-mode. Participants were interviewed and satisfaction surveys were administered to obtain feedback.

Results:

A total of 37 participants completed the course and evaluations. The combined mode had better measurement accuracy, acupuncture safety, and operating time (P < 0.05), and no pneumothoraxes occurred. Among both participant groups, the combined mode allowed the student group to learn quickly and the intern group to become more proficient. Both interviews and satisfaction surveys yielded positive feedback.

Conclusions:

Using a combined mode for UDA can improve its performance greatly. The combined mode is definitely helpful for learning and promotion of UDA.

INTRODUCTION

Acupuncture has been widely used to treat many diseases safely and effectively.¹ As with any medical intervention, acupuncture may also cause adverse effects. For example pneumothorax is caused by acupuncture needles penetrating too deeply and piercing the lungs—even causing death in some cases.

The current authors developed ultrasound (US) detection acupuncture (UDA) to address this issue and improve patient safety. UDA is an innovative acupuncture technique that is used before puncturing at the dangerous acupoints around the chest. The depth of the lung is measured by US, and then a needle shorter than that depth is selected for acupuncture. This needle will naturally not puncture the lung and thus avoid pneumothorax.³ To be proficient in UDA, in addition to participating in the training course, learners must also use simulations to practice. Acupuncture Simulation model GB21 (ASM21) is a simulation with the GB-21 acupoint as the target. The acupuncturist can practice operating UDA in GB-21. When the acupuncture point is punctured or goes deep enough to cause pneumothorax, an alarm is activated.^4,5

For implementation of UDA, the most-important element is accurate identification of US lung images. Given that most acupuncturists have less exposure to US techniques during their training, this aspect of education must be especially strengthened during UDA training. In the initial implementation, based on current clinical practice for ultrasonography (USG), a single mode (a B-mode), was used to identify the hyperechoic reflex caused by the pleura and air in a lung as a method to locate the lungs.^3,6 However, this single-mode method requires a long learning time. Therefore, a combined mode was subsequently proposed, in which the B-mode was used with an M-mode, because a special “seashore sign” can identify the pleura in the M-mode.⁷

Both the single and combined mode can be used for lung identification by UDA, but few studies have compared the effects of these 2 operating methods for acupuncturists to learn to identify the lungs. The flipped classroom has been widely used in many acupuncture settings.^8,9 For health providers, such as acupuncturists, who are extremely busy and have strong self-learning motivation, the flipped classroom is the most-suitable training method. To compare the two US methods, a flipped classroom was used for evaluation.

This study used a flipped classroom to enable students and interns to use US to practice on ASM21 and to compare the 2 US operating methods (single mode and combined mode) for detecting lung depths. The study also enabled the participants to complete their UDA learning. By evaluating the their performance in terms of measurement accuracy, acupuncture safety, operation time, and incidence of pneumothorax, it became possible to compare the pros and cons of the 2 methods.

MATERIALS AND METHODS

Ethics Approval

The institutional review board of Changhua Christian Hospital, Changhua, Taiwan, approved this study (Approval no. 181248).

Participant Recruitment and Involvement

This study recruited 20 students and 20 interns in Traditional Chinese medicine (TCM) from the Changhua Christian Hospital, and China Medical University Hospital, Taichung City, Taiwan. Students who had not taken the acupuncture class were excluded. The participants signed consent forms before study enrollment. After study enrollment, participants underwent precourse interviews and then completed the UDA flipped classroom course. After course completion, a Direct Observation Procedural Skills (DOPS) test of 2 US operating methods were carried out and the scores were recorded. Postcourse interviews and satisfaction surveys were conducted to shed light on the learning experiences of the participants (Fig. 1).

FIG. 1.

Study flow chart. UDA, Ultrasound detection acupuncture; DOPS, Direct Observation Procedural Skills.

UDA Flipped Classroom

A preliminary draft of the course was designed by US clinicians, clinical acupuncturists, and medical-education experts, and the DOPS test was created to assess the participants' skills. The DOPS test is an assessment tool used to evaluate the performance of a trainee in learning a practical procedure.¹⁰ DOPS records were used to generate 4 major parameters to compare the performances: (1) measurement accuracy; (2) acupuncture safety; (3) occurrence of pneumothorax; and (4) operating time. Measurement accuracy refers to the depth of the acupuncture simulation model's lung minus the participant's measured lung depth. Acupuncture safety refers to the depth of the acupuncture simulation model's lung minus the length of the needle selected by the participants. These definitions were used as the basis to evaluate the results.

The UDA course consisted of 3 main components: (1) medical education by self-directed learning; (2) patient safety and importance of chest acupuncture points, and (3) practice of UDA. Practice of UDA was taught as a 1-hour hands-on class to demonstrate the 2 US operating methods (single and combined modes). The actual practice was performed by the participants with the ASM21, a US-penetrable acupuncture model that can be used for UDA practice. The ASM21, an acupuncture simulator model of GB-21, was developed to help the trainees to manage this acupoint easily. (Fig. 2). The ASM21 model was designed with a sensor that detects whether the needle is placed in the correct position and within a safe depth; an alarm sounds when the needle reaches the lung. Given that this model was constructed with material that is penetrable by US, the trainees could also measure the safe needle depth when the model was used together with a US machine (Fig. 3).

FIG. 2.

Acupuncture simulator model of GB-21 (ASM21).

FIG. 3.

Ultrasound images in the combined mode and single mode. Left: B-mode (A shows high echo reflex). Right: B-mode + M-mode (B shows “seashore” line ).

Single mode indicates use of the B-mode alone to display a highly reflective image of the pleura to confirm the lung depth. This method is generally used in clinical practice.³ The combined mode—B-mode + M-mode—uses the B-mode and the seashore line visualized on the M-mode to confirm the lung depth. Chest specialists commonly use this method.⁴ The current study used the Leltek US machine (Leltek, New Taipei, Taiwan), a portable wireless product. On completion, the assessments and satisfaction survey were administered to the participants.

Five experts were invited to evaluate the course with questionnaires containing 15 items. Inter-rater reliability and a generalizability coefficient were used for statistical analysis based on the scores given by the raters.^11,12 Course validity was calculated using the content validity index, which determined the ratio of experts who agree with each other.¹³ Participants first identified GB-21 on the ASM21 and scanned the surface of the GB-21 using the Leltek US. Next, they measured the depth of the lung via the single or combined mode. Then, each participant chose a needle with a length that did not exceed the measured depth to prevent pneumothorax. Finally, the instructor recorded the measured depth, needle length, total operating time, and occurrence of pneumothorax.

Evaluation

Satisfaction survey

A satisfaction survey form was issued after the course. In addition, a section was provided for participants to express their opinions and suggestions.

Evaluation of 2 US operations

The DOPS recorded the operation time, US measurement of lung depth, and if each participant selected the appropriate needle length based on the US measurement. These records were used for the 4 major parameters to compare the performances (measurement accuracy, acupuncture safety, pneumothorax occurrence, operating time). For measurement accuracy (depth of simulation model's lung minus participant's measured lung depth), values closer to 0 indicated a more-accurate measurement. For acupuncture safety (depth of simulation model's lung minus participant's selected needle length), a negative value indicated a lung puncture. Finally, the operation time represented the time of the entire UDA operation. The shorter the operating time was, the easier it was for the student or intern to master the operation. These factors were used as the basis for evaluating the results.

Statistical analysis

A paired t-test was used to compare the differences between the 2 US operating methods for all participants. The results of the 2 methods were also separately calculated for the student and intern groups using a Wilcoxon signed-rank test. The results of the 2 groups for both the single and combined modes were compared using a Mann–Whitney-U test. Finally, the participants' measurement failure rates for both operating methods were expressed.

This study used the statistical software packages Microsoft Excel 2019 and GNOVA version 3.1 to perform the calculations. A web-based statistics program Social Science Statistics was also used.^*

RESULTS

Participants

The 39 participants recruited into the study included 20 fourth-year medical students of TCM and 19 interns from the Hospital. Of the 20 medical students, 2 were unable to complete the course due to health problems. Thus, a total of 37 participants completed the course and assessment (Table 1). The interns had taken US classes in school before the study, and the students had not done so.

Table 1.

Participants' Characteristics

		Sex
Participant group	n or N	Female	Male	Age	Previous ultrasound class
Student	18	10	8	24.58 ± 6.35	No
Intern	19	8	11	28.95 ± 2.86	Yes
Total	37	18	19	26.76 ± 5.39	—

UDA Flipped Classroom Course

The UDA course contained 2 online classes and 1 hands-on class. The first 2 classes were (1) medical education via self-directed learning and (2) patient safety and importance of chest acupuncture points. The third class was involved with practice of UDA with the 2 US operations. Five experts evaluated all 3 classes and reached a high agreement regarding the UDA flipped course. The generalized coefficient was 0.71, and the content validity index was 1.0. Both values indicated good reliability and validity.

Satisfaction Survey

A total of 24 satisfaction questionnaires were completed by 6 of the 19 interns and all 18 of the 18 students. The average stratification of 5 points for the teacher part were 100, 98.9, 100, 97.8, and 100; for the course part, they were 97.8, 96.7, 98.9, 97.8, and 98.9. Overall, average satisfaction was very high, indicating that the participants were very satisfied with the course.

Evaluation of the 2 US Operating Methods

The DOPS scores of the 2 US operating methods were recorded and calculated, with the following statistical results.

Participants performed well in the combined mode for measurement accuracy, acupuncture safety, and operating time, achieving statistical differences. Although the average value of the single mode was close to 0 in terms of measurement accuracy, it showed that the participants' measured lung depth was closest to the real model lung depth. However, this average was obtained by averaging many positive and negative values. Thus, not all participants measurements were accurate (Table 2).

Table 2.

Comparison of the 2 Operating Methods for All Participants (N = 37) by Paired t-Test

Evaluation	Single mode (B-mode)	Combined mode (B-mode + M-mode)	P-value
Measurement accuracy (mm)	0.68 ± 11.00	7.27 ± 6.38	0.00631*
Acupuncture safety (mm)	8.84 ± 7.05	13.32 ± 4.78	0.00144*
Operating time (sec)	76.65 ± 51.60	52.76 ± 30.68	0.00435*
Pneumothorax occurrence	5.4% (2/37)	0% (0/37)	—

^* Statistically significant.

sec. seconds.

Measurement accuracy showed that the combined mode made it easier for participants to meet the requirements for accurate measurement. (Table 3) The single-mode negative value of the average value resulted from the inaccurate measurement by many participants. The measured lung depth was even higher than that in the actual model lung. The depth was so deep that a negative value appeared after the subtraction.

Table 3.

Comparison of the 2 Operating Methods in the Student Group Versus the Intern Group

Evaluation	Groups Student (18) Intern (19)	Single mode (B-mode)	Combined mode (B-mode + M-mode)	P-value
Measurement accuracy (mm)	Students	−6.72 ± 8.21	5.89 ± 7.47	0.00544*
	Interns	7.68 ± 8.46	8.58 ± 5.00	0.65994
Acupuncture safety (mm)	Students	5.89 ± 5.89	12.33 ± 5.34	0.00496*
	Interns	11.63 ± 7.05	14.26 ± 4.12	0.23014
Operating time (sec)	Students	81.00 ± 56.48	58.83 ± 35.32	0.07346
	Interns	72.53 ± 47.71	47.00 ± 25.15	0.01352*
Pneumothorax occurrence	Students	11.1% (2/18)	0% (0/18)	—
	Interns	0% (0/19)	0% (0/19)	—

^* Statistically significant.

sec, seconds.

For acupuncture safety, the combined mode was safer, and no pneumothoraxes occurred in the model. For student group, given that the students had not taken US courses before and were unfamiliar with US operations, there was no difference in the operation times between the 2 methods. However, the single mode still tended to take more time, indicating that the combined mode was still easier to master for student group. For intern group, they had already taken the US course, so there was no difference in the measurement accuracy between the 2 methods for intern group, and the performance was good. However, the combined mode made it easier to identify the lungs, so the operation time was shorter to achieve a statistical difference for intern group (Table 3).

The performance of the intern group was particularly notable for measurement accuracy, reaching statistical differences. Although the other 2 measured parameters did not reach statistical significance, the intern group still showed a trend of better performance. Based on these findings, no differences were noted in the 4 parameters between the intern group who had taken the US course and the student group who has not taken the US course. Operation of the combined mode was easier to learn and master, which effectively reduced the learning threshold (Table 4).

Table 4.

Comparison of Single mode Versus Combined mode for Students and Interns

Evaluation	Mode	Students (18)	Interns (19)	P-value
Measurement accuracy (mm)	Single	−6.72 ± 8.21	7.68 ± 8.46	0.00*
	Combined	5.89 ± 7.47	8.58 ± 5.00	0.36282
Acupuncture safety (mm)	Single	5.89 ± 5.89	11.63 ± 7.05	0.01684
	Combined	12.33 ± 5.34	14.26 ± 4.12	0.36812
Operating time (sec)	Single	81.00 ± 56.48	72.53 ± 47.71	0.4965
	Combined	58.83 ± 35.32	47.00 ± 25.15	0.37886
Pneumothorax occurrence	Single	5.4% (2/37)	0% (0/37)	—
	Combined	5.4% (2/37)	0% (0/37)	—

^* Statistically significant.

In the evaluation of the US operating method, measurement accuracy was obtained by subtracting the lung depth of the real model from the participant's lung depth measured. The closer the value was to 0, the higher the accuracy was. However, some participants had inaccurate measurements and even negative values. Data analysis showed interesting phenomena. The student group had a high error rate due to their unfamiliarity with US manipulation, with 72.2% (13/18) with the single mode but 11.1% (2/18) with the combined mode. The intern group performed better with the single mode, with an error rate of 21.1% (4/19), but the error rate with the combined mode decreased to 5.3% (1/19). Both of these findings showed that the combined mode greatly improved the ability of the participants to manipulate their needles (Table 5).

Table 5.

Participants' Measurement Failure Rates Using the 2 Operating Methods

Participant group	Single mode (B-mode)	Combined mode (B-mode plus M-mode)
Students (18)	72.2% (13/18)	11.1% (2/18)
Interns (19)	21.1% (4/19)	5.3% (1/19)

Availability of Data and Material

The data from this study is available on Google Drive for reference.^†

DISCUSSION

The advantages of low cost, bedside availability, and no radiation exposure make US an indispensable diagnostic tool in modern pulmonary medicine.¹⁴ Therefore, this study used US as an auxiliary tool to reduce pneumothorax caused by acupuncture, which is in line with the trend in previous research. Based on this principle, this study also developed a method to detect the integrity of the pleura by the seashore line in the M-mode and provided it for use in acupuncture practice. Many specialists use US to diagnose lung disease, and US is used in emergency and intensive care units as well.^15–17 Saraogi et al. proposed the presence of pleural lines, lung sliding, A-lines in 2-dimensional imaging, and the seashore sign in M-mode as a US operating method to detect the complete shape of the lung.⁵ However, the current authors specifically propose using the seashore sign in M-mode together with the B-mode as a standard method of assessing the lungs for acupuncture practice.

The combined mode was easier to learn. Statistical analysis showed that all 37 participants using the combined mode performed better than with the single mode in terms of measurement accuracy, acupuncture safety, and operating time. Between the 2 participant groups, it was better for the student group to use the combined mode in terms of measurement accuracy and acupuncture safety, and for the intern group to use the combined mode in terms of operating time.

This finding meant that the combined mode could help the performance of students with no experience in US operation and can shorten the operation time of more-experienced interns—that is, the combined mode can speed up the entry of junior learners and improve the proficiency of senior learners. Although the 2 groups of students and interns had different learning backgrounds in US because the measurement of lung depth used in this study is not the major part of US in school, the interns did not learn these 2 methods. However, interns have a better grasp of US instruments and operations, which makes them perform better in learning. Between-group comparison showed that, with the single mode (which is more difficult to master) the intern group performed better than the students. However, between-group comparison for the combined mode (which is easier to master) showed that the performance of the 2 groups was similar. This finding demonstrated that the combined mode could improve learning efficiency.

The most interesting study results were the measurement-failure rates. Compared with the single mode, use of the combined mode versus for both the student (72.2%; 11.1%) and intern groups (21.1%; 5.3%) reduced the failure rate significantly. This approach is undoubtedly a great boon for learners. Regarding the incidence of pneumothorax, the single mode still had 2 occurrences, whereas the combined mode had none, indicating its superiority further. There was better accuracy, better safety, and shorter operating time with the combined mode, supporting that all participants mastered the skill more easily. These results are beneficial for promoting UDA as well. In summary, both methods could be used to measure lung depth, but the combined mode has better safety and is easier to learn. Thus, the combined mode is a helpful tool for promoting UDA.

Participants agreed with the use of the flipped classroom in courses such as acupuncture that require hands-on practice. This finding is in line with those of Liebert et al., who reported that medical students had a very positive view regarding simulation-based flipped classrooms in surgical practice. The flipped classroom method can be applied successfully to the surgical-practice environment and may provide additional benefits, compared with traditional courses.¹⁸

The current study participants were unanimously positive about the introduction of US to enhance the effectiveness of acupuncture. Participants all expressed that US reduced the psychologic pressure of using acupuncture at dangerous acupoints and improved their clinical skills.

Students were also satisfied with the flipped classroom learning model, which allowed them to choose time freely for prepreparation and to watch and study the class repeatedly. The participants controlled their learning paces and methods.¹⁹ Therefore, more practice time is needed in future courses.

Canellas et al. investigated students' opinions about the flipped classroom learning model for US and found that the flipped classroom was an effective and desirable method to learn US without increasing the burden of the class.²⁰ Interestingly, Bashir et al. compared US teaching in the flipped classroom with traditional face-to-face teaching.²⁰ They found similar learning outcomes between the 2 approaches, but students in the flipped classroom maintained a better self-learning effect 2 months after the end of the teaching.²¹ Cheng et al. also used TCM students as participants to observe the effectiveness of a flipped classroom.²² That study found that students benefited from flipped classrooms, and a questionnaire survey also showed that most participants made relatively more-serious preparations before class and actively participated in the classroom learning activities.

However, our research targeted TCM students and used acupuncture as a learning project, which enabled better understanding of the impact of the flipped classroom method on TCM professionals' learning.²² Meng et al. used the flipped classroom method in bilingual education for acupuncture, which improved students' acupuncture and English proficiency. However, the course did not specifically focus on the acupuncture technique, which was different from the innovative acupuncture technology proposed in this present research.²³ Obviously, the combined mode was more beneficial to the beginners. In the future, the study sample size could be increased and clinical acupuncturists could be recruited.

CONCLUSIONS

The use of UDA in the combined mode can reduce measurement failure rate greatly and improve learning efficiency. The results of this study showed that the combined mode is definitely helpful for learning and promoting UDA.

AUTHORs' CONTRIBUTIONS

All authors contributed to the study conception and design. Material preparation, and data collection and analysis were performed by Drs. Hou, Chang, and Huang. The first draft of the article was written by Dr. Chen, and all authors commented on subsequent versions of the article. All authors read and approved the final article.

AUTHOR DISCLOSURE STATEMENT

No financial conflicts of interests exist.

FUNDING INFORMATION

This work was supported by the Ministry of Science and Technology (MOST 108-2511-H-371-001-MY2) and Changhua Christian Hospital (108-CCH-IRP-063).