JOURNAL OF SURGICAL RESEARCH 76, 17–21 (1998)ARTICLE NO. JR985264

Swine and Dynamic Ultrasound Models for TraumaUltrasound Testing of Surgical Residents

J. Ali, M.D., M.Med.Ed., FRCS(C), FACS,1 Joan P. Campbell, M.D., Theo Gana, M.D., Ph.D.,Peter N. Burns, Ph.D., and M. Gage Ochsner, Jr., M.D., FACS

University of Toronto, Toronto, Canada; and the Memorial Medical Centre, Savannah, Georgia

Presented at the Annual Meeting of the Association for Academic Surgery, Dallas, Texas, November 6–8, 1997

INTRODUCTIONBackground. Trauma ultrasound workshops have been

recommended for training surgical residents. We as-The role of ultrasound in blunt torso trauma assess-sessed the teaching effectiveness of the workshop, com-

ment is increasing [1–3]. Previous studies have shownparing swine and dynamic patient ultrasound models.that nonradiologists can be effectively taught this tech-Materials and methods. MCQ exams on ultrasoundnique for assessing the multiply injured patient [4–7].physics and practical skills tests with and withoutWe have also shown [6] that surgical residents improvepericardial or peritoneal fluid using four swines andtheir ability to detect intraabdominal and pericardialeight dynamic patient ultrasound videos were used tofluid following the trauma ultrasound workshop.compare pre- and postworkshop performance in 18

The Advanced Trauma Life Support (ATLS) pro-surgical residents (Group I) and a matched controlgram is widely accepted as a method of teaching physi-group of 18 (Group II). Paired t tests and unpaired t

tests for paired and unpaired data, respectively, were cians the concepts of trauma resuscitation [8–10]. In-used for analysis with a P õ 0.05 being considered sta- corporation of the teaching of the principles of traumatistically significant. ultrasound assessment utilizing the swine model dur-

Results. Mean scores (% correct response) { SD were ing the Advanced Trauma Life Support course for sur-as follows (*P õ 0.05 vs Group I). gical residents has been reported [11]. It has been

suggested that with very minimal extension of thetime allotted for the standard ATLS program it is pos-

MCQ Video Swine sible to effectively introduce surgical residents to theprinciples of trauma ultrasound assessment during aGroup Pre Post Pre Post Pre Post

standard ATLS course [11]. The most recent versionI 26.1 { 6 85.0 { 9 22.2 { 15.8 89.6 { 9.8 14.6 { 7.1 53.2 { 11.8 of the ATLS manual has included a brief introductoryII 27.8 { 6 26.1 { 7* 23.6 { 9.5 18.8 { 8.8* 14.3 { 5.2 12.2 { 5.4*

video and a brief discussion of the role of the ultra-sound in assessing the multiply injured patient [12].

For the swine model, the best scores were with pericar- In one study [11] the swine model was used not onlydial fluid (25.0% pre vs 69.4% post in Group I) and the for teaching but also for testing the surgical residents’worst scores were with RUQ fluid (5.6% pre vs 22.2% ability to detect pericardial and intraperitoneal fluid.post in Group I). Postworkshop dynamic video scores We have also reported previously on the use of staticwere always higher than the swine model scores in ultrasound images for testing the effectiveness of theGroup I (100% correct video scores for pericardial fluid). trauma ultrasound workshop for surgical residents

Conclusions. This study confirms the trauma ultra- [6]. The role of the dynamic ultrasound video for test-sound workshop teaching effectiveness. For testing, ing and teaching trauma ultrasound assessment re-the swine model (especially RUQ) was more difficult. quires clarification. We were interested in determin-In postcourse evaluation, the dynamic human video ing the merits of using the swine model as opposedwas considered more relevant, realistic, and less costly to a dynamic ultrasound video model for testing thefor repeated testing of the residents. q 1998 Academic Press effectiveness of this program. We compared the perfor-

Key Words: trauma ultrasound; resident education; mance of surgical residents in a multiple choice exami-ultrasound workshop.nation, a swine model, and a dynamic ultrasoundmodel before and after a standardized trauma ultra-sound workshop consisting of didactic ultrasoundphysics sessions, equipment demonstration, litera-1 To whom correspondence should be addressed at Department ofture, and methodology review as well hands-on prac-Surgery, University of Toronto, Room 311-100 College St., Toronto,

Ontario, Canada, M5G 1L5. tice with human models [4, 5].

17 0022-4804/98 $25.00Copyright q 1998 by Academic Press

All rights of reproduction in any form reserved.

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{ 6.5% (NS). Postworkshop scores were 85.0 { 9% forGroup I and 26.1 { 7.0% (P õ 0.05) for Group II. Theresidents who completed the trauma ultrasound work-shop, therefore, had a statistically significant improve-ment in MCQ scores after the workshop.

Swine Model Overall Scores

The percentage of correct responses for all locationsusing the swine model is summarized in Fig. 2. Thecontrol group had a preworkshop score of 14.3 { 5.2%compared to a postworkshop score of 12.2 { 5.4% (NS).The group attending the workshop had a preworkshopscore of 14.6 { 7.1% with a statistically significant in-crease in score to 53.2 { 11.8% following completion ofthe workshop. There was no difference in the prework-shop scores between the two groups and the postwork-shop score was not statistically different from the pre-workshop score in the control group.

Dynamic Video Overall ScoresFIG. 1. MCQ scores. The control group did not improve theirscores while the workshop group had a statistically significant im- The overall dynamic video scores for all locations areprovement in MCQ scores after the workshop.

summarized in Fig. 3. The control group showed nosignificant change in scores (pre 23.6 { 9.5% vs. post18.8 { 8.8%). The residents completing the ultrasoundMETHODSworkshop had a preworkshop overall dynamic videoscore of 22.2 { 15.8% which was not statistically differ-Eighteen surgical residents (Group I) from the University of To-

ronto attended a standard trauma ultrasound workshop as outlined ent from the prevideo scores of the control group. How-above. This group and a matched control group (n Å 18, Group II) ever, the postworkshop scores in this group were statis-which did not attend the ultrasound workshop had an MCQ test tically significantly higher with a score of 89.6 { 9.8%.consisting of 10 items, each with a stem and five choices. The MCQ

The overall scores in the dynamic video were alwaysexam was administered prior to the workshop and repeated afterstatistically significantly higher than the scores achievedthe workshop.

A swine model was used to mimic hemopericardium or hemoperito- using the swine model in both control and workshopneum by instilling 100 ml/kg of saline into the peritoneal cavity and groups.10 ml/kg into the pericardial sac [11]. With appropriate placementof the ultrasound probes the residents were asked to identify whether Scores for the Four Separate Probe Locationsfluid was present or not in the standard locations: right upper quad-rant, left upper quadrant, suprapubic, and pericardial locations. Four The scores for peritoneal (P), right upper quadrantanesthetized swines weighing between 18.8 and 22.4 kg were used (R), left upper quadrant (L), and suprapubic (S) loca-with one swine containing both pericardial and peritoneal fluid, an-other having only pericardial fluid but no peritoneal fluid, a thirdwith peritoneal but no pericardial fluid, and a fourth without fluidin the peritoneal or pericardial cavity.

Eight dynamic ultrasound videos which were taped from real pa-tients were also used for testing the residents. The videos consistedof two in each position, one being with and the other without pericar-dial or peritoneal fluid. The residents were randomly assigned thetesting stations and were individually requested to indicate theirresponse on an answer sheet. They were requested to indicatewhether fluid was present or not. The percentage of correctly identi-fied fluid in the different locations was calculated and the scoreswere compared by paired t tests and unpaired t tests for paired andunpaired data, respectively. A P õ 0.05 was considered statisticallysignificant.

RESULTS

The data are reported as means { standard deviation.

MCQ Scores

Figure 1 summarizes the MCQ scores for both groupsof residents. As indicated, there was no difference be- FIG. 2. Overall swine model scores. The precourse scores weretween the two groups in the preworkshop scores with similar for both groups but the workshop (experimental) group

showed a statistically significant improvement in postcourse scores.Group I having scores 26.1 { 6.1% and Group II 27.8

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FIG. 3. Overall video scores. The overall dynamic video scoresFIG. 5. Scores for the four separate probe locations in the work-were statistically significantly higher in the workshop (experimental)

shop (experimental) group. After the workshop the performance forgroup after the workshop. There was no improvement in the controleach probe location was improved. The suprapubic and pericardialgroup and the precourse scores were similar for both groups.locations provided the highest scores.

tions of the probe are summarized in Fig. 4 (controlgroup) and Fig. 5 (workshop group). These are the the two sets of scores for any of the locations. Also, thescores obtained utilizing the swine model. In the con- scores were lowest in the right upper quadrant locationtrol group the pericardial scores were 26.4 { 13.5% in the swine model.pre- with a postworkshop score of 18.1 { 14.4% (NS). The residents completing the workshop showed noCorresponding scores for the right upper quadrant in statistically significant difference in the preworkshopthis group were 4.2 { 9.6% pre and 5.6 { 10.7% post scores compared to the control group with preworkshop(NS). The left upper quadrant scores were 9.7 { 15.2% scores of 25.0 { 12.1% for the pericardial location, 5.6pre and 11.1 { 12.8% post (NS). The suprapubic scores { 10.7% for the right upper quadrant location, 9.7 {in the swine model for the control group were 16.7 { 12.5% for the left upper quadrant location, and 18.1 {12.1% pre and 13.9 { 12.8% post (NS). The control 14.4% for the suprapubic location. Postcourse scores ingroup showed no improvement in performance between this group were 69.4 { 22.0% for the pericardial loca-

tion (P õ 0.05), 22.2 { 16.9% for the right upper quad-rant (P õ 0.05), 51.4 { 16.0% for the left upper quad-rant (P õ .05), and 70.8 { 26.1% (P õ 0.05) for thesuprapubic location. The lowest scores were againnoted in the right upper quadrant for the residentscompleting the ultrasound workshop with the highestscores being in the pericardial and suprapubic locationsin the swine model.

Dynamic Video Scores for the Different ProbeLocations

The dynamic video scores for each of the probe loca-tions for the control group are shown in Fig. 6 and forthe workshop group in Fig. 7.

Scores for the pericardial location of the probe inthe control group were identical pre- and postworkshop(36.1 { 23.0%). The right upper quadrant scores forthis group were 16.7 { 24.3% preworkshop and 8.3 {19.2% (NS) postworkshop. The scores for the left upperquadrant probe location were 16.7 { 24.3% pre and

FIG. 4. Scores for the four separate probe locations (control 11.1 { 21.4% post (NS). The suprapubic location scoresgroup). The scores were highest in the pericardial location and therefor the control group were 27.8 { 25.6% pre and 19.4were no differences in the control group between the pre- and post-

workshop scores. { 25.1% post (NS).

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FIG. 6. Dynamic video scores—control group. The scores did not FIG. 8. Scores when only one of three peritoneal sites were cor-improve for any of the probe locations among the control group. rectly assessed. The control group showed no improvement in perfor-

mance whereas the experimental (workshop) group showed an over-all improvement after the workshop to a 70% correct response.

The group completing the ultrasound workshopshowed scores similar to those of the control group prior trol group and the scores were always higher utilizingto the workshop with pericardial scores of 30.6 { the dynamic video model as opposed to the swine25.1%, right upper quadrant scores of 19.4{ 25.1%, left model. The best performance following the workshopupper quadrant scores of 13.9 { 23.0%, and suprapubic was in the identification of pericardial fluid utilizingscores of 25.0 { 25.7%. All 18 residents who completed the dynamic video.the program correctly identified pericardial fluid afterthe workshop. Other scores in this group were 91.7 { Scores When Any One of Three Peritoneal Sites19.2% with the right upper quadrant, 80.6 { 25.1% Were Correctly Assessedfor the left upper quadrant, and 86.1 { 23.0% for the

By design, the random assignment of the residentssuprapubic probe location. All these scores were statis-to the swines and probe locations required that theytically significantly higher than the scores in the con-determine whether fluid was present or not at only onelocation at a time without knowing whether they hadpreviously identified fluid in another peritoneal site inthe same animal. Thus, in the same animal a residentmay detect, for example, right upper quadrant fluid butnot suprapubic fluid. In the clinical trauma scenario itmay be argued that the detection of fluid in any of thethree peritoneal sites is considered a positive ultrasoundassessment for hemoperitoneum. For practical pur-poses, therefore, if the resident fails to identify fluid inone location but identifies it in another location this maynot be a significant clinical error. With this in mind, weanalyzed the data further by assigning a correct re-sponse if any one of the three locations within the perito-neal cavity was correctly identified as containing fluid.

The results of this analysis are shown in Fig. 8. Thecontrol group had a preworkshop score of 29.0 { 3.0%compared to a postworkshop score of 33.0 { 5.1% (NS).The preworkshop score of the experimental (workshop)group was not different from that of the control group(29.1 { 4.0%). However, the postworkshop score in theswine model for the experimental group was 70.1 {4.2% which was a statistically significant improvementcompared to the preworkshop scores.

FIG. 7. Dynamic video scores—experimental (workshop) group.Postcourse evaluation. The residents were re-The postworkshop scores were improved for all locations with a 100%

correct response in the pericardial location. quested to complete a questionnaire at the end of the

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21ALI ET AL.: TRAUMA ULTRASOUND TESTS

workshop. There was 100% completion of this question- quired) utilizing the swine model, the performance inthe dynamic video model was much better and part ofnaire and in it the objectives of improving their ability

to identify intraperitoneal and pericardial fluid using the reason may be because it more accurately representsthe real clinical trauma situation. Our study suggeststhe ultrasound technique were considered to be met in

100% of the cases. All the residents considered this skill that this technique of utilizing the dynamic ultrasoundvideo could prove very useful in testing the effectivenessto be an essential component of trauma assessment and

recommended that it be incorporated as a standard of the ultrasound trauma workshop for surgical resi-dents. Conceivably, this may also be extended to testingpart of our resident training program.

When asked to compare the dynamic video with the the effectiveness of trauma ultrasound workshops forfully qualified practicing surgeons who participate inswine model, 94% of the trainees indicated that the

dynamic video was much more relevant and 89% con- this program.sidered it more realistic.

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