Models for teaching emergency medicine skills

METHODS & TECHNIQUES cadavers; education, teaching models

Models for Teaching Emergency Medicine Skills Teaching and retaining psychomotor skills presents problems in emergency medicine. A variety of models, including animals, plastic models,, paid or unpaid volunteers, patients recently pronounced dead, and cadavers (the bodies of people who donate their bodies to science), have been developed to alleviate this problem. Practical and ethical concerns in using these models are discussed, with an emphasis on the cadaver model and on those procedures that are best taught on cadavers. [Nelson MS: Models for teaching emergency medicine skills. Ann Emerg Med March 1990;19:333-335.] INTRODUCTION Learning to perform procedures is an integral part of training in emergency medicine. In their statement on the recommended core skills for undergraduate training in emergency medicine,~ the Society of Teachers of Emergency Medicine (now the Society for Academic Emergency Medicine) identified 26 important procedures with which an emergency physician should be familiar. The problem confronting teachers of emergency medicine is how to best train medical students and residents to perform these and other procedures. Even practicing physicians have skills that may have deteriorated due to low patient volume or decreased clinical time as a result of other commitments, such as administrative responsibilities or research. In addition, the nature of emergency medicine is such that often there is no time to explain slowly and methodically how to perform certain procedures. The patient who presents with an acute upper airway obstruction that needs a cricothyrotomy will not be happy waiting while the physician explains to a resident the pros and cons of various approaches. Patients who are already apprehensive about being cared for by physicians who they do not know and did not choose are unlikely to have their anxiety alleviated by overhearing someone explain to a neophyte how to perform a certain procedure.

Marc S Nelson, MD Stanford, California From the Department of Emergency Services, Stanford University Hospital, Stanford, California. Received for publication May 17, 1989. Revision received August 25, 1989. Accepted for publication October 2, 1989. Address for reprints: Marc S Nelson, MD, FACER Department of Emergency Services -- H1250, Stanford University Hospital, Stanford, California 94305.

MODELS AVAILABLE FOR T E A C H I N G A variety of models exist to assist with teaching procedures. These include live or dead animals, plastic models, paid or unpaid volunteers, patients recently pronounced dead, and cadavers. A brief discussion of these models will show their advantages and disadvantages. The use of animals is a controversial topic in today's society with animal support groups becoming increasingly vocal and influential in their demands to reduce the number of animals used in research and teaching. Aside from the ethical issues involved in using animals, which are not trivial, differences in anatomy and physiology often make animals poor choices for teaching. However, unlike most plastic models and cadavers, animals will bleed when cut and do add a certain realism when performing such procedures as cutdowns. Whether this is necessary for good teaching is disputable. Obviously, plastic models, such as CPR mannequins, avoid normative concerns with regard to consent. When they are well designed and accurately reflect the human body, they can be useful adjuncts. Mannequins exist for teaching everything from venipuncturc and intubation to place-

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TEACHING SKILLS Nelson

FIGURE 1. Procedures for which the cadaver is an e x c e l l e n t t e a c h i n g model. m e n t of urinary catheters and emergency c h i l d b i r t h . M a n y accessories, s u c h as a r t i f i c i a l blood, u r i n e a n d a m n i o t i c fluid, are available to add to t h e r e a l i s m of t h e s e d e v i c e s . T h e d r a w b a c k s to s u c h d e v i c e s are, of course, an obvious lack of r e a l i s m in even the best models. The uniform i t y of m o d e l s is q u i t e u n l i k e the variety encountered among human beings. In a d d i t i o n , e v e n t h e b e s t m o d e l s are far from perfect. For exa m p l e , t e a c h i n g a c h i n - l i f t or jawthrust m a n e u v e r is next to impossible on even the n e w e s t CPR m a n n e quins. In addition to being expensive to p u r c h a s e i n i t i a l l y (eg, $500 to $1,000), s u c h d e v i c e s m a y b r e a k d o w n and u s u a l l y r e q u i r e p e r i o d i c m a i n t e n a n c e to f u n c t i o n o p t i m a l l y . H o w e v e r , t h e y are a p p r o p r i a t e for many procedures, especially those taught to large groups of people, such as CPR. Volunteers, e i t h e r paid or unpaid, are another alternative. W i t h volunteers, the question of consent is obviated, except for v o l u n t e e r s w h o are being paid and are " v o l u n t e e r i n g " for purely financial reasons. T h e use of volunteers is c o m m o n in p h y s i c a l diagnosis courses, p a r t i c u l a r l y for t h e teaching of pelvic examinations. Unf o r t u n a t e l y , as p r o c e d u r e s b e c o m e m o r e p a i n f u l a n d p o t e n t i a l l y dangerous, fewer v o l u n t e e r s are l i k e l y to be found. A l t h o u g h it often occurs in subtle ways, few p h y s i c i a n s can deny having seen a p a t i e n t w h o was suffering a c a r d i a c a r r e s t u s e d for " t e a c h i n g purposes." This m a y occur after the p r o n o u n c e m e n t of a p a t i e n t w h e n s t u d e n t s p r a c t i c e i n t u b a t i n g or less o b v i o u s l y by c o n t i n u i n g to a t t e m p t to r e s u s c i t a t e a p a t i e n t w h o c l e a r l y has no chance of recovery. Thus, a 90-year-old patient with a "downt i m e " of 20 m i n u t e s w h o has been in asystole for 30 m i n u t e s before arrival may, for example, get intubated, have central IV lines placed, and have cutd o w n s p e r f o r m e d . C l e a r l y , t h e patient has given no consent for practicing these procedures. Unfortunately, it is a very effective w a y to teach, so despite ethical issues, 2,3 it is l i k e l y to continue. The last m o d e l to be considered is c a d a v e r s . A l t h o u g h n o t w e l l de176/334

Airway Management

Endotracheal intubation (oral, nasal, tactile) Placement of nasopharyngeal and oropharyngeal airways Placement of EOAs Use of McGill forceps Cricothyrotomy Chin-lift or jaw-thrust maneuver Wound Care

Suturing (simple, complex lacerations) Local anesthesia Nerve blocks Chest Procedures

Needle thoracostomy Thoracostomy Thoracotomy Pericardiocentesis Abdominal Procedures

Nasogastric tubes Peritoneal lavage Neurologic or Neurosurgical Procedures

Gardner-Wells tongs Burr holes Miscellaneous

Foley catheters Arthrocentesis Cutdowns Nasal packs (anterior, posterior) Nail removal scribed in e m e r g e n c y m e d i c i n e literature, their use in teaching has been n o t e d by surgeons4, s and internists. 6 Cadavers (for our purposes), either fresh or preserved, are the bodies of p e o p l e w h o h a v e s p e c i f i c a l l y given t h e i r c o n s e n t for t h e i r bodies to be used for teaching or research. The issue of consent is therefore moot, and such cadavers are useful for a variety of teaching purposes. There are very few procedures t h a t cannot be done as w e l l on a fresh cadaver as t h e y could be on a live h u m a n being. Unfortunately, fresh cadavers do present some disadvantages, such as the potential for t r a n s m i s s i o n of the AIDS virus. The risk, however, is no higher than w i t h live p a t i e n t s and can be reduced by taking appropriate precautions. In fact, the risk m a y even be less as n e i t h e r t h e t e a c h e r nor the s t u d e n t should feel any sense of urgency that m i g h t prevent being espec i a l l y careful. T h e use of preserved cadavers is m u c h less o p t i m a l as procedures are m o r e r e a l i s t i c on fresh cadavers; however, in certain circums t a n c e s t h e y c a n s t i l l be e f f e c t i v e teaching models. Cadavers are, of course, l i m i t e d in a v a i l a b i l i t y and, in c e r t a i n i n s t i t u Annals of Emergency Medicine

tions, expensive. At the Stanford U n i v e r s i t y School of M e d i c i n e , the a v e r a g e c o s t of a f r e s h c a d a v e r is about $400. M o s t fresh cadavers will not last m o r e than a few days, and it is wise to plan laboratory sessions so that the chest and a b d o m e n are not entered u n t i l the last day.

CADAVERS I N T E A C H I N G The successful use of cadavers requires a certain a m o u n t of training, skill, and b a c k g r o u n d knowledge. Alt h o u g h t h e r e is s o m e f l e x i b i l i t y in h o w m a n y s t u d e n t s can w o r k on the same cadaver, there are also limitations, m a i n l y depending on the proc e d u r e s t h a t are b e i n g t a u g h t . We have found t h a t as in a n a t o m y laboratory, groups of five or six students are ideal. W i t h c e r t a i n p r o c e d u r e s , s u c h as e n d o t r a c h e a l i n t u b a t i o n , more students may practice; with other procedures, such as saphenous vein cutdowns, the l i m i t m a y be as low as two. O b v i o u s l y , t h e n u m b e r of t i m e s each s t u d e n t practices is important. W h i l e c a d a v e r s are e x c e l l e n t for t e a c h i n g a v a r i e t y of p r o c e d u r e s , clearly some things w o r k better t h a n o t h e r s . P r o c e d u r e s t h a t w o r k ex19:3 March 1990

Placement of central lines Subclavian, internal jugular, femoral Orthopedic procedures Casts Splints Reduction of dislocations Intraosseous infusions Removal of corneal foreign bodies Lumbar taps

2

Arterial blood gases Peripheral IV lines Incision and drainage of abscesses Mouth-to-mouth or mouth-to-nose resuscitation 3

t r e m e t y well are listed (Figure 1). Alm o s t every technique used in managing airways can be well taught w i t h t h e cadaver model; the o n l y exception is m o u t h - t o - m o u t h resuscitation (although this d e m o n s t r a t e s the advantage of m o u t h - t o - m a s k resuscitation, a t e c h n i q u e t h a t w o r k s quite w e l l w i t h c a d a v e r s and gives stud e n t s an o p p o r t u n i t y to p r a c t i c e a c h i n - l i f t or j a w - t h r u s t m a n e u v e r ) . Virtually every aspect of w o u n d care also can be taught, and the chance to s u t u r e f a c i a l l a c e r a t i o n s or o t h e r c o m p l e x lacerations is very valuable. A v a r i e t y of c h e s t p r o c e d u r e s also m a y be practiced, a l t h o u g h w e reco m m e n d f i l l i n g t h e p e r i c a r d i a l sac w i t h fluid before a t t e m p t i n g pericardiocentesis. Subcutaneous emphys e m a can easily be produced by perf o r m i n g a n e e d l e t h o r a c o s t o m y and t h e n v e n t i l a t i n g the patient. Arthrocentesis generally works best w h e n the joints are filled w i t h m e t h y l e n e blue. We generally inject one half of the cadaver while leaving t h e o t h e r h a l f in i t s n a t u r a l state. T h i s gives the s t u d e n t a c h a n c e to c o m p a r e ease of e n t r y and to v i e w n o r m a l joint fluid. The p l a c e m e n t of u r i n a r y c a t h e t e r s a l s o is e a s i l y taught. M a n y cadavers have urine in t h e i r b l a d d e r s ; h o w e v e r , in its abs e n c e it is e a s y to i n j e c t a s m a l l a m o u n t of w a t e r colored w i t h y e l l o w food coloring. Although there are many proc e d u r e s t h a t are t a u g h t v e r y successfully using cadavers (Figure 1 is by no m e a n s exhaustive), there are a few that do not w o r k nearly as well 19:3 March 1990

FIGURE 2. P r o c e d u r e s for w h i c h t h e c a d a v e r i s a f a i r or g o o d t e a c h i n g model.

FIGURE 3. P r o c e d u r e s for w h i c h t h e cadaver is a poor teaching model.

(Figure 2). P l a c e m e n t of central lines can often be difficult to teach. A l t h o u g h i n t e r e s t i n g m o d i f i c a t i o n s have been d e v e l o p e d to m a k e t h i s m o r e successful, 7 t h e y can be quite t i m e cons u m i n g . W h e n p r o p e r l y done, t h i s w o r k s w e l l ; w h e n u n s u c c e s s f u l , it can be e x t r e m e l y frustrating, often l e a d i n g to c u t d o w n s to l o c a t e t h e vein. O r t h o p e d i c procedures also can be a problem. The cold, c l a m m y skin of the cadavers often makes casting t e c h n i c a l l y as w e l l as a e s t h e t i c a l l y difficult. Reduction of dislocations is easily taught, although after the first few t r i e s t h e j o i n t o f t e n m o v e s so easily it loses s o m e realism. Also, it is s o m e t i m e s d i f f i c u l t to d i s l o c a t e joints. Lumbar taps can be practiced, but it is difficult to o b t a i n spinal fluid. O p h t h a l m o l o g i c procedures are difficult s e c o n d a r y to the loss of intraocular pressure. Finally, there are some procedures (Figure 3) that for a n u m b e r of reasons do n o t w o r k . N o t e , h o w e v e r , that this list is e x t r e m e l y limited.

ADDITIONAL CONSIDERATIONS T h e use of cadavers need not, of c o u r s e , be l i m i t e d to p r o c e d u r e s . There are few emergency physicians w h o will n o t benefit from taking an old, d u s t y a n a t o m y book and spending a few hours dissecting a h a n d or reviewing the a n a t o m y of the chest or abdomen. N e w i n s t r u m e n t s , such as flexible laryngoscopes or nasopharyngoscopes, m a y be used to increase staff f a m i l i a r i t y and c o m f o r t before t h e y are used in an e m e r g e n c y setting. F i n a l l y , s t u d e n t e v a l u a t i o n s conf i r m faculty observations of the value of cadavers. The students u n i f o r m l y rate the cadaver laboratories as excellent.

ETHICAL DILEMMAS The ethical concerns in using anim a l s or r e c e n t l y d e c e a s e d p e o p l e have b e e n briefly discussed, and it w o u l d be remiss not to m e n t i o n furAnnals of Emergency Medicine

ther s o m e of t h e problems w i t h using cadavers, from b o t h a s t u d e n t ' s and teacher's perspective as w e l l as from a more global perspective. The attitude of m e d i c a l students toward cadavers has been a m p l y discussed by Fox,8, 9 a m o n g others, w h o s h o w e d that although students believed t h e y were doing s o m e t h i n g disrespectful, t h e y u n d e r s t o o d i t was for a g o o d cause. T h e use of the h u m a n body for t e a c h i n g as a p h i l o s o p h i c a l c o n c e r n is b e y o n d the scope of this article. Readers w i t h a further interest in the subject should study the articles by Kass 1° and Feinberg. n

SUMMARY W h e t h e r it is m a i n t a i n i n g s e l d o m l y used skills in the already pract i c i n g e m e r g e n c y p h y s i c i a n or t h e teaching of n e w skills to medical students and residents, cadavers provide a suitable model. Unlike animal models or patients w h o have just suffered a cardiac arrest, t h e r e are few ethical d i l e m m a s in using the body of a person who has consented to don a t e his body to science. T h e w i d e v a r i e t y of p r o c e d u r e s t h a t m a y be taught with a correspondingly high degree of r e a l i s m m a k e s cadavers a t e a c h i n g t o o l t h a t s h o u l d n o t be overlooked.

REFERENCES

1. Society of Teachers of Emergency Medicine: Core content for undergraduate education in emergency medicine. Ann Emerg Med 1985;14: 474-476. 2. Iserson KV: Using a cadaver to practice and teach. Hastings Cent Rep 1986;3:28-29. 3. Culver CM: Using a cadaver to practice and teach. Hastings Cent Rep 1986;3:29. 4. Fullerton LR, Pratzman RN, Wincheski J: Arthroscopy training. Am J Sports Med 1981;9: 38-39. 5. Narwani KP, Reid EC: Teaching transurethral prostatic resection using cadaver bladder. J Urol 1969;101:101. 6. Weaver ME, KyrovacJP, Frank S, et ah A cadaver workshop to teach medical procedures. Med Educ 1986;20:407-409. 7. Reid JDS, Vestmp JA: Use of a simulation to teach central venous access. J Med Educ 1988;3: 196-197. 8. Fox RC: The autopsy: Its place in the attitude-learning of second-year medical students, in Essays in Medical Sociology. New York, John Wiley & Sons, 1979, p 51-77. 9. Lief HI, Fox RC: Training for "detached concern," in Lief HI, Lief VF, Lief NR (eds}: The Psychological Basis of Medical Practice. New York, Harper and Row, 1963, p 12-35. 10. Kass LR: Thinking about the body. Hastiugs Cent Rep 1985;1:20-30. 11. FeinbergJ: The mistreatment of dead bodies. Hastings Cent Rep 1985;1:31-37. 335/177