29. C o n t r o l of t he t r o l l e y and p a t i e n t i s o n l y p o s s i b l e wi t h t he si de l oad method.
30 . The c a r r y handl es ar e c o n s i d e r e d t oo s h o r t but t h e i r l engt h i s de t e r mi n e d by t he amount of f l e x when l i f t i n g t he t r o l l e y .
31. The t r o l l e y f l e x e s l e n g t h wi s e when l i f t e d g i v i ng t he appear ance of weakness though w i t h i n t he B r i t i s h STandard. 32. Ther e i s a r i s k of i n j u r y from t he s l i d e s on t he l ower f r ame. E l e v a t i on 33. The t r o l l e y i s capabl e of e l e v a t i o n as recommended. - 9 9 -
34. The t r o l l e y i s s t a b l e but does not appear so w i t h movement e s p e c i a l l y end t o end.
35. I t can be wheel ed w h i l e e l e v a t e d but t h i s has been banned due t o an a c c i d e n t .
36. The r a t c h e t l ock p r o v i d e s seven p o s i t i o n s but t h e r e a r e no s a f e t y f e a t u r e s and f a i l u r e can o c c u r .
3 7 . The e l e v a t i n g mechanism can be o p e r a t e d from bot h s i d e and end p o s i t i o n s but t h e end handl e becomes bent and i t i s not o p e r a b l e when t he t r o l l e y i s i n t he T r e n d e l e n b e r g p o s i t i o n . 3 8 . As s t a t e d above t he o p e r a t i n g han dl e s cannot
be used w i t h t he t r o l l e y i n t he T r e n d e l e n b e r g p o s i t i o n .
39. These handl e s a r e not al ways a c c e s s i b l e i n t he ambul ance.
B a c k r e s t
4 0 . When o p e r a t i n g t he b a c k r e s t t h e r e i s a danger of t r a p p i n g hands e s p e c i a l l y when l o w e r i n g i t . 41 . See 4 0 .
42. The r e a r e no s a f e t y l ocks on t he mechani sm. 43. Fi v e t o seven p o s i t i o n s ar e p r o v i d e d bet ween
h o r i z o n t a l and 60°
44 . The s he e t e d base of t he b a c k r e s t i s c o n s i d e r e d a de quat e s up por t f o r c a r d i a c massage.
Hype r - e x t e n s i on
45. T hi s f a c i l i t y t akes t oo long t o o p e r a t e . 46. I t may p r o v i d e adequat e t i l t t o m a i n t a i n an
open a i r w a y .
47 . I t s o p e r a t i o n i n t he ambul ance i s unknown as t h e r e ar e no r e p o r t s of i t s use.
T r e n d e l e n b e r g p o s i t i o n
48 . Thi s p o s i t i o n p r o v i d e s a t i l t of 10° t o t he h o r i z o n t a l .
49. I t can be used o u t s i d e but i s v e r y d i f f i c u l t t o o p e r a t e in t he ambul ance.
50. Access t o t he o p e r a t i n g handl es i s d i f f i c u l t when t he t r o l l e y i s i n i t s l owest p o s i t i o n . Fowl er s pos i t i on
51. Thi s p o s i t i o n i s a v a i l a b l e .
52. I t i s p o s s i b l e t o o p e r a t e t he mechanism f o r t he p o s i t i o n out of t he ambul ance but v e r y d i f f i c u l t i n i t .
53. I t does not cause any embarrassment t o t he c a s u a l t y .
54. The r e i s no access t o t he handl es i n t he ambu l a n c e .
Mat t ress
55 . The m a t t r e s s i s r e p o r t e d c o m f o r t a b l e i n most c a s e s , though t h e r e were a few r e p o r t s of d i s c o m f o r t .
56 . The con t ou r ma t t r e s s i s c o n s i d e r e d t o p r o v i d e a de quat e s e c u r i t y from s l i p p i n g but t he C . P . R . m a t t r e s s i s s l i p p e r y .
57. The a b i l i t y of t he m a t t r e s s t o c o n t o u r round t he p o s i t i o n s i s d i c t a t e d by t he foam t h i c k ness.
A c c e s s o r i e s
58. I n f u s i o n st ands and oxygen b o t t l e h o l d e r s a r e a v a i l a b l e but are not al ways p r e s e n t i n t he ambul ance when needed and can cause h a n d l i n g p r o b l e ms . The c a r d i a c mo n i t o r st and i s not avai l a b l e .
59. L i f e suppor t i s onl y p o s s i b l e o u t s i d e t he
ambul ance by t he use of t he above equi pment or a d d i t i o n a l s t a f f a i d .
3 . 5 . 3 The above e v a l u a t i o n shows t h a t a l t h o u g h t he e x i s t i ng t r o l l e y per f or ms a l l t he r e q u i r e d f u n c t i o n s i n t h e o r y , i t i s not al ways p o s s i b l e t o use them i n p r a c t i c e , p a r t i c u l a r l y i n t he ambul ance. T hi s
t r o l l e y has been in s e r v i c e f o r t en y e a r s and though i t has i mproved handl i ng and p a t i e n t comf or t t h e r e ar e ar ea s where improvements can be made.
4 F I RS T PROTOTYPE
4. 1 New d e s i g n - I n t r o d u c t i o n
4 . 1 . 1 From t h e e v a l u a t i o n of t he e x i s t i n g t r o l l e y i t be came a p p a r e n t t h a t t h e r e were many a r e a s where im pr ovement s would i n c r e a s e p a t i e n t comf or t and
s e c u r i t y and t he t r o l l e y u s a b i l i t y . The i n t e i — f a c e w i t h t he ambulance body t oday r emai ns one of t he maj or probl em ar eas and a l t h o u g h t h i s cannot be c o m p l e t e l y sol ved w i t h a new desi gn of t r o l l e y i t i s p o s s i b l e t o mi ni mi se t h e adv er se e f f e c t by r e c o g n i z i n g t hese r e s t r i c t i o n s and d e v e l o p i n g t h e new t r o l l e y t o accommodate them. I t woul d seem u n l i k e l y t h a t a new ambul ance body w i l l be d e v e l o p ed i n t h e near f u t u r e t h a t w i l l remove most o f t he p r e s e n t r e s t r i c t i o n s , but even i f one were d e v e l o p ed i t would s t i l l be n e c e s s a r y f o r t he t r o l l e y t o be u s a b l e i n an e x i s t i n g ambul ance. I t was
d e c i d e d , t h e r e f o r e , t h a t i t woul d be n e c e s s a r y t o pay c a r e f u l a t t e n t i o n t o t h e way i n whi ch v a r i o u s mechanisms ar e o p e r a t e d and t o t he p o s i t i o n of t h e o p e r a t i n g l e v e r s , as e i t h e r one of t h e s e i n f l u e n c e s t he o t h e r . Thi s shoul d i n c r e a s e t he u s a b i l i t y of t he t r o l l e y e n a b l i n g i mproved p a t i e n t c omf o r t and s e c u r i t y and b e t t e r h a n d l i n g q u a l i t i e s t o be
o b t a i n e d .
4 . 1 . 2 When t h e e x i s t i n g range of t r o l l e y s c u l m i n a t i n g i n t h e ' Supe r 4' model i s exami ned i t i s p o s s i b l e t o t r a c e an e v o l u t i o n a r y p a t t e r n t h a t shows how
a d d i t i o n a l f e a t u r e s have been added t o each v e r s i o n of t he t r o l l e y i n t u r n t o c r e a t e a new model .
Thi s has r e s u l t e d i n many of t he h a n d l i n g pr obl ems and t he i n c r e a s e d wei ght of t he t r o l l e y t o d a y .
As t he wei ght was c o n s i d e r e d a maj or pr obl em i t was f e l t i mp o r t a n t t o a c h i e v e we i g ht r e d u c t i o n w i t h o u t
loss of s t r e n g t h . A t t e n t i o n s h o u l d , t h e r e f o r e , be gi v e n t o t he i n t e g r a t i o n of t he d i f f e r e n t f u n c t i o n s i n t o a whole desi gn and t o t he way in which
components were a t t a c h e d , as a r e d u c t i o n i n t he number of c a s t i n g s used would a f f e c t some we i g ht s a v i n g . S i m i l a r l y , i t was f e l t t h a t an
e x a m i n a t i o n of t he s t r u c t u r e of t he t r o l l e y and