MEDICAL EDUCATION

Formal Procedural Skills Training Using a FreshFrozen Cadaver Model: A Pilot Study

JOSEPH J. OCEL, NEENA NATT, ROBERT D. TIEGS, AND AMINDRA S. ARORA*

Mayo Clinic College of Medicine, Rochester, Minnesota

Graduating medical students are expected to be proficient in a number of procedural skills.A structured curriculum is infrequently available. In addition, the use of a mannequintends to be unrealistic and students continue to have some anxiety when performing proce-dures on patients. This pilot study was designed to demonstrate the utility of a fresh frozencadaver model in practicing procedural skills as compared to mannequins. Seven third-yearstudents carried out a number of basic procedural skills using a mannequin model and afresh frozen cadaver. We surveyed the students after they had carried out the procedureson the different models with regards to ease of procedure, the sense of realism and theirsuccess rate. The pilot course improved the overall confidence of the students in perform-ing basic skills. In addition, despite the fact that the mannequin was somewhat easier toperform a number of procedures on, the fresh frozen cadaver was a more realistic modeland the preferred model for practicing the skills. The fresh frozen cadaver is a feasibleand valid instructional tool for training procedural skills and has the advantage of beingmore realistic than a typical mannequin model. Clin. Anat. 19:142–146, 2006.VVC 2005 Wiley-Liss, Inc.

Key words: procedural skills; cadaver; mannequins; pilot study

INTRODUCTION

Research indicates that program directors and

medical staff expect graduating medical students to

be proficient in basic procedural skills (Langdale

et al., 2003). Few medical schools, however, have

structured curricula to ensure that students have

been taught to perform these procedures. Instead,

most medical schools expect students to learn proce-

dural skills while on clinical clerkships or rotations

(Nelson and Traub, 1993). Inconsistent opportunities

to perform procedures, variability in the quality of

supervision, and the reluctance of some patients to

have medical students perform a procedure on them

are some of the limitations of this traditional appren-

ticeship model of learning.

The best educational method(s) to teach proce-

dural skills remains a matter of debate. Mannequins,

animals, human cadavers, and more recently, virtual

or interactive computer programs and simulated

patients (for landmark recognition) have been used

for teaching procedural skills (Weaver et al., 1986;

Kneebone et al., 2002). To our knowledge, the fresh

frozen cadaver (FFC) has not been evaluated as a

tool in this setting. Compared to the traditional

cadaver, FFC may provide a better model for proce-

dural skills training, as tissue planes are not distorted

by the embalming process (Kowlowitz et al., 1990).

This pilot study was conducted as part of the plan

for Mayo Medical School to develop a procedural

skills course for third-year medical students. The

objectives of the study were three-fold: (1) to deter-

mine the perceived impact of a procedural skills

course on student confidence levels; (2) to determine

*Correspondence to: Amindra S. Arora, MD, Mayo Clinic Col-

lege of Medicine, 200 First Street SW, Rochester, MN 55905.

E-mail: arora.amindra@mayo.edu

Received 22 December 2004; Revised 24 February 2005;

Accepted 25 February 2005

Published online 10 November 2005 in Wiley InterScience (www.

interscience.wiley.com). DOI 10.1002/ca.20166

VVC 2005 Wiley-Liss, Inc.

Clinical Anatomy 19:142–146 (2006)

the feasibility of using a FFC model as a novel

instructional method; and (3) to compare a FFC

model to a standard set of M models.

MATERIALS AND METHODS

Seven volunteer third-year medical students at

Mayo Medical School participated in a 3-hr proce-

dural skill laboratory consisting of three mannequin

stations and one fresh frozen cadaver (FFC) station.

The setting was the Procedural Skills laboratory, a

unit specifically designed for faculty, residents and

medical students to learn and perfect clinical proce-

dures on cadaveric specimens. The mannequin

stations comprised venipuncture and intravenous

cannulation (IV), nasogastric tube (NGT) placement,

and lumbar puncture (LP) models. The FFC station

was used for training all of the aforementioned

procedures and urinary catheterization. Students

were provided with an orientation packet of indica-

tions and contraindications, prerequisite equipment,

sterile technique and instructions for each of the

procedures.

The FFC remained frozen until 24–36 hr before

the study commenced and was fully thawed before

the initiation of the course. The students rotated

around the stations, attempting the procedure on the

mannequin before the FFC. Two physician educa-

tors supervised and provided feedback to students

throughout the course. In the mannequin and FFC

models success in IV insertion was verified when

‘‘back flow’’ of colored fluid was seen in the intrave-

nous line portion. Similarly for the lumbar puncture

procedure, backflow of clear fluid indicated success.

For NGT placement success was determined by

hearing the ‘‘rush of air’’ in the stomach with a

stethoscope placed in the epigastrium and a 50-cc

syringe of air flushed through the NGT.

A pre-procedure questionnaire documented stu-

dents’ prior experience with each procedure. A post-

procedure questionnaire asked students to compare

the mannequin and FFC model for each procedure

in terms of preference and perception of realism. A

5-point Likert scale was used to rate pre- and post-

procedure confidence levels. The Likert scale was

used to rate the confidence from 1–5 where 1 was

least confident and 5 was most confident.

RESULTS

Five students had some prior experience perform-

ing IV cannulation and urinary catheter insertion.

Four students had prior experience performing LPs

and three students had prior experience placing

NGT. The success rate, preference, and perception

of realism for each procedure are shown in Table 1

for the two models.

All students successfully carried out IV cannula-

tion using the mannequin. Only two students suc-

cessfully completed this procedure on the FFC (Fig.

1a,b). Although the procedure was more difficult

using a FFC, six students preferred to perform the

procedure on the FFC model and perceived that it

was a more realistic model than the mannequin. One

student was undecided as to which of the models

was more realistic for this procedure. All students

successfully carried out an LP on both the manne-

quin and FFC models. Once again, the students pre-

ferred performing the LP on the FFC and perceived

that it was more realistic than the mannequin model.

None of the students were successful in placing the

NGT in either the mannequin model or the FFC,

however, although five students preferred attempting

to place the NGT in the FFC because it was per-

ceived to be more realistic. All students successfully

inserted a urinary catheter in the FFC (a mannequin

model was unavailable for this procedure).

Individual and group mean confidence levels pre-

and post-procedure are shown in Table 2 and Figure

2, respectively. The confidence level of all students

tended to increase after performing each proce-

dure, with the exception of NGT placement in

the mannequin model (confidence levels appeared

unchanged). Mean group confidence levels increased

the most after IV cannulation (2.25–3.90) on the

mannequin model.

Analysis of the open-ended questions showed that

the course was well received by all students. Specifi-

cally, the students appreciated the opportunity to

practice procedures in a non-critical environment

and stated that a half-day procedural skills course in

the third-year curriculum would be effective use of

their time, and would aid them in becoming a more

competent member of the healthcare team on clini-

TABLE 1. Comparison of Success Rate, Preference, andRealism for Mannequin Model and Fresh Frozen Cadaver*

IV NGT LP

Man FFC Man FFC Man FFC

Success rate 7 2 0 0 7 7Preference 1 6 2 5 0 7Realism 0a 6 0 7 0 7

*The table demonstrates that the fresh frozen cadaver is pre-

ferred over the mannequin model and is more realistic, though

the success rate may have been higher for the Man model. FFC,

fresh frozen cadaver; Man, mannequin model; IV, intravenous

cannulation; NGT, nasogastric tube; LP, lumbar puncture.aOne student was undecided.

143Procedural Skills Using Cadavers and Mannequins

Fig. 1. A: Student carrying

out an IV cannulation on a stand-

ard Mannequin model. B: Studentcarrying out an IV cannulation on

a fresh frozen cadaver model.

144 Ocel et al.

cal rotations. Furthermore, students believed that a

procedural skill course would save time on clinical

rotations, as residents would not have to spend as

much time teaching the procedures.

DISCUSSION

This pilot study highlights the benefits of a proce-

dural skills course in the third year of Mayo Medical

School’s undergraduate curriculum. The increased

confidence experienced by students at the end of

the course may make them more likely to volunteer

to perform procedures in the clinical setting. The

acquisition of procedural skills in a more structured

environment during the early stages of training has

been shown to have a long-term effect on the level

of competence in procedural skills and self-rated

confidence (Liddell et al., 2002). The procedural

skills session also provided the opportunity to per-

form procedures in a safe, non-critical, and sup-

ervised learning environment devoid of the time

pressure often associated with performing procedures

during clinical rotations. In keeping with other stud-

ies, students welcomed the opportunity to practice

their skills in this setting (Das et al., 1998; McLeod

et al., 2001).

The results of the study indicate that the FFC is

a feasible and valid instructional tool for training

procedural skills and has the advantage of being

more realistic than a typical mannequin model.

When compared to the latter, the FFC carried out

equally well in terms of success rate for completing

the studied procedures, with the exception of IV

cannulation. The major drawback when using the

FFC for this procedure was vein slippage. The man-

nequin model for IV cannulation was perceived as

being unrealistic (the vein in the mannequin arm

was clearly marked and did not behave like a typical

vein in a patient). The FFC and mannequin, there-

fore, should have a complementary role in a proce-

dural skills course. The pilot helped to identify the

strengths of each model for the procedures that were

studied.

There have been a number of studies highlighting

the deficiencies associated with learning to perform

procedures in the clinical setting and advocating the

use of formal procedural skills training for medical

students (Remmen et al., 2001; van der Vlugt and

Harter, 2002; Elnicki and Fagan, 2003; Fincher and

Lewis, 1994; Oxentenko et al., 2003). Despite these

studies, there continues to be a paucity of such

courses in the undergraduate curriculum. This may

be due to a reluctance to add a new course in an

already packed curriculum or concerns about the

cost of such training. Research has indicated, how-

ever, that clinical skills centers can be cost-effective

(Hao et al., 2002). In addition, cost can be mini-

mized if the FFC is used to practice a variety of pro-

cedures multiple times.

This pilot study has a number of limitations. The

sample size was small as a consequence of the lim-

ited availability of fresh frozen cadavers and physi-

cian educators at the time the study was conducted.

Consequently, statistical analysis could not be

applied to the results. Although it was not an objec-

tive of this study, a study could be designed to

assess the process (i.e., counseling skills and sterile

technique) in addition to the outcome (i.e., success

Fig. 2. Improvement in confidence level before (Pre) and after

(Post) attempt of the various procedural skills for mannequins and

cadavers.

TABLE 2. Change in 5-Point Likert Scale Rating*

Man FFC

IV NGT LP IV NGT LP UC

Pre-procedureconfidence 2.25 3.35 2.88 2.63 3.38 3.25 3.38

Post-procedureconfidence 3.90 3.35 3.65 2.88 3.63 3.95 3.98

*For the FFC and Mannequin (Man) model the mean pre- and

post-procedure confidence levels improved for each procedure

for the seven students. Likert Scale: 1 is least confident and 5 is

most confident. FFC, fresh frozen cadaver; Man, mannequin

model; IV, intravenous cannulation; NGT, nasogastric tube; LP,

lumbar puncture; UC, urinary catheterization.

145Procedural Skills Using Cadavers and Mannequins

vs. failure). We demonstrated, however, that the

FFC model is a realistic and acceptable model to

use in teaching procedural skills.

In conclusion, a formal procedural skills course is

a means of exposing students to common procedures

in a supervised and controlled environment before

their exposure to such procedures in the hospital

and clinic setting. Building such a course into the

undergraduate curriculum may provide the means to

close the gap between expectations of program

directors and the actual experience of medical school

graduates relative to basic, procedural skills. Manne-

quin and FFC models can have a complementary

role in teaching procedural skills.

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