Paediatric Chest Immobilisation Devices

Introduction

The options for paediatric chest radiography are basically erect or supine. Supine paediatric chest radiography has some significant limitations. Whilst paediatric imaging departments have been able to dedicate the resources (equipment and training) to achieving high quality paediatric chest radiography, some non-paediatric institutions that cater for occasional paediatric patients have resorted to developing innovative solutions. This page considers the options for paediatric chest radiography.

Acknowledgement

The content on this page draws heavily from various books, articles and photographs by Catherine Gyll.

The Commercial Paediatric Chest Positioning Aids

The Pigg-o-stat

<a class="external" href="http://www.nationwidechildrens.org/GD/Applications/News/mediafiles/pigostat.jpg" rel="nofollow" target="_blank"></a> <a class="external" href="http://www.nationwidechildrens.org/GD/Applications/News/mediafiles/pigostat.jpg" rel="nofollow" target="_blank">http://www.nationwidechildrens.org/GD/Applications/News/mediafiles/pigostat.jpg</a>

I have never used a pigg-o-stat so I am going to let Jeremy Enfinger do the talking... "If you have an absolutely uncooperative patient that requires immobilization, the pigg-o-stat is the method of choice for radiographers. Most come with different sized adjustable flanks and you may want to sneak a peak at your patient before bringing them into the room to estimate the appropriate size. If you've never used one or seen one, they look like some sort of dark-age torture device, which they could easily turn into if you let the patient sit in them too long. You simply place them into the seat with arms above their head and close the flanks. Make sure to lock them in place. If you have all of this set up in advance, the patient should be in and out in just a few seconds" You can visit Jeremy's entertaining and informative website at <a class="external" href="http://bloggingradiography.blogspot.com/2007/05/pediatric-chest-x-ray.html" rel="nofollow" target="_blank">http://bloggingradiography.blogspot.com/2007/05/pediatric-chest-x-ray.html</a> The manufacturers website lists the following features Seat platform turns on bearings. Cassette carrier has adjustable horizontal and vertical movement for precise positioning of film The scale in degree readings on table top ensures exact duplication of positions for re-check examinations. Adjustable seat in center of table top with openings for patients legs. Seat platform can be rotated horizontally to any degree and position Form-fitting body, head and arm supports of transparent plexiglass are provided. Adjustable for patients from infants to 3-1/2 years of normal size for age Lead shield has adjustable conventional markers and adjusts up and down for various examinations. Elimination of position and immobilizing problems makes it easier to make exposure at proper stage of respiration. Spring-balanced cassette holder accommodates any size cassette needed. Device is easily cleaned and sterilized. <a class="external" href="http://www.piggostat.com/new/about_our_products.asp" rel="nofollow" target="_blank">http://www.piggostat.com/new/about_our_products.asp</a> <a class="external" href="http://images.dotmed.com/cgi-bin/size.pl?t=2&a=3&i=663449_2.jpg" rel="nofollow" target="_blank">http://images.dotmed.com/cgi-bin/size.pl?t=2&a=3&i=663449_2.jpg</a> I have never known a radiographic positioning device to polarise opinion like the pigg-o-stat. I found this to be the case many years ago when I was considering options for paediatric chest imaging, and if the comments on <a class="external" href="http://bloggingradiography.blogspot.com/2007/05/pediatric-chest-x-ray.html" rel="nofollow" target="_blank">Jeremy Enfinger's blog</a> are any indication, the jury is still out on this one!

<a class="external" href="http://recia.files.wordpress.com/2010/04/torture-machine-for-chest-x-ray.jpg" rel="nofollow" target="_blank">http://recia.files.wordpress.com/2010/04/torture-machine-for-chest-x-ray.jpg</a>	Child positioned for PA erect chest radiography using a pigg-o-stat and Philips DR
<a class="external" href="http://recia.files.wordpress.com/2010/04/torture-machine-2.jpg" rel="nofollow" target="_blank">http://recia.files.wordpress.com/2010/04/torture-machine-2.jpg</a>	Child positioned for lateral erect chest radiography using a pigg-o-stat and Philips DR

The DIY Devices

I have seen a few home-made paediatric chest radiography positioning devices in my travels. These are a few of them (including my own).

Papua New Guinea

I found this chair in an X-ray department in Papua New Guinea. This was typical of the innovative spirit of 'radiography in difficult circumstances' that I saw throughout the country. I did not see the chair in use. The chair appears to have the advantage of allowing the child to sit with their knees below their hips. The cassette has height adjustable. The backward slope of the backboard prevented the cassette from falling forwards but probably had undesirable consequences in terms of increased chances of producing a lordotic projection. In spite of this limitation, I give them full points for producing their own innovative device in a context of very limited resources.

The Fuller Chair

This was my own answer to years of frustration with supine paediatric chest radiography. It also addressed most of the limitations that I had found in DIY paediatric chest 'chairs' that I had used previously. The Fuller chair had the following features hook and loop lap strap to keep child in the chair hidden magnetic strip in the backboard to hold the side-marker which also prevented the cassette from falling forwards. Three different heights of cassette lifter for different sized children 1mm lead backing to protect the operator Facility for lateral chest imaging cleanable hardwearing surface The major disadvantage of this type of chair is that it needs to be used with a sponge under the child's bottom. The child's hips should be higher than their knees. I have put together a separate page of Fuller Chair engineering drawings

This photograph shows the Fuller Chair setup for lateral chest radiography. The child does not have to move between AP and lateral projections. I found that it was better to use a 15 degree wedge sponge behind the child rather than the sponge shown in the photograph. The 15 degree sponge tended to lean the child forwards allowing more scope for lifting the child's chin up. It also helped to minimise the tendency to produce an apical projection.

The Published Inhouse/DIY Devices

Catherine Gyll's Generic Design for 1- 6 months Old Babies

Good radiographs of these babies in the erect position are almost impossible without a special cassette holder. A simple wooden one [left]... is easily made by the hospital carpenters and can stand on the end of the X-ray table. Flat wooden bars of varying height which fit in the slots of the uprights and rest on the crossbar, provide an easy way of raising the height of the cassette. Foam pads of varying thicknesses to cover the seat do the same for the height of the baby. Velcro [hook and loop tape] is stuck all around the sides of the seat. Quoted from Catherine Gyll and Susan Cleaver, A handbook of Paediatric Radiography, Blackwell Scientific Publications, Oxford, 1977, p 25.

Westminster Hospital Chest Stand

Catherine Gyll, Design for A paediatric Chest-stand, Radiography, Feb 1983, Vol 49, No 578, p 35

This is the paediatric chest stand as designed by Catherine Gyll and published in the Radiographer in 1983 (Catherine Gyll, Design for A paediatric Chest-stand, Radiography, Feb 1983, Vol 49, No 578, p 35). The design features the following cheap and easy to construct lead protection for the operator the baby's/child's knees are positioned below the hips Adjustable cassette height accommodate 18 x 24cm (10 x 8 inch) and 18 x 24cm (10 x 12 inch) cassettes Velcro straps to secure patient's legs

Preventing the Lordotic Projection

adapted from Radiography, Preventing Lordotic Projection of the Chest, Catherine Gyll, December 1983, V49, No 588, pp291-293	Catherine Gyll considered the unintentional lordotic positioning error to be of such importance that she wrote an article on the subject. (Radiography, Preventing Lordotic Projection of the Chest, Catherine Gyll, December 1983, V49, No 588, pp291-293) Up to 1/3 of the baby's lung field can be hidden below the diaphragm on AP/PA chest radiography if care is not taken to avoid a lordotic projection. A 15 degree wedge sponge placed behind the baby's chest can assist considerably in avoiding an unintentional lordotic projection.
	A baby child will tend to end up in this position when seated with legs horizontal. This position will result in a lordotic projection.
	If the baby is seated on a small sat and a 15 degree sponge placed behind the child's back, a more satisfactory position is achieved.

Notes on Paediatric Chest Radiography

• Children over the age of 5 years are usually able to be positioned in a PA erect position for chest radiography. (some 4 year olds will be sufficiently compliant for PA/AP erect chest radiography)
• There is very little difference between PA and AP chest radiography in children (Caffey 1978, and Hochschild and Cremin, 1975)
  
• There is very little difference between left and right lateral chest radiography in children

• AP Chest radiography has several advantages over PA chest radiography in children
  
• The radiographer can watch the child's breathing in order to expose on full inspiration
• It is easier to hold a child straight and still
• The child can watch the tube being centred and the beam collimated without turning around
• The child's arms should be held against the side of the child's head with elbows flexed and pointing forwards.
• an 18 x 24cm is suitable for children up to about 2 years
• an 24 x 30cm cassette is suitable for children up to about 7 or 8 years
• movement of the abdomen rather than the chest is watched to ensure exposure on full inspiration
• Exposure time should be less than 0.02 seconds
• A paediatric lead rubber apron should be employed for gonad protection for the child
• The adult holding the child should be protected by at least 0.5mm lead equivalent
  

(Catherine Gyll, Noel Blake, and A Thornton. Paediatric Diagnostic Imaging, 1985, p4,John Wiley and Sons, New York)

• It is undesirable to position the child/baby with the legs horizontal for chest radiography- some kind of seat is preferred such that the child's hips are higher than his/her knees
• When examining children over the age of 3 it is useful to have the child practice taking a deep breath before the exposure.

Case 1

	The child is positioned for AP chest radiography in the erect sitting position. The adult who is holding the child's arms is holding them out to the sides (abducted) rather than as shown below. This position allows the child's head to fall forwards and rotate.
	The child's arms are correctly positioned for the lateral projection.

Case 2

This 6 year old girl presented to the Emergency Department with a temperature of 39 degrees. She was assessed and referred for chest radiography

At 6 years of age the radiographer correctly considered that she would be able to stand against the erect bucky for her chest radiography. At this age AP erect radiography has advantages over PA erect radiography. The radiographer noted what appeared to be abnormal right hilar opacity and abnormal opacity if the RUL. The appearance was not easily accounted for given that the most likely cause of the patient high temperature was infection. The radiographer considered that the unusual appearance of the hilum might reflect malpositioning (unintended lordotic positioning) rather than hilar pathology. The AP erect chest was repeated with the aim of correcting the lordotic malposition	The repeated AP erect position showed considerable improvement- this image is easier to interpret- the patient has a silhouette sign involving the RML and right heart border and abnormal opacity in the RUL (compare with LUL)
The lateral projection image demonstrated evidence of collapse/consolidation of the RML and RUL	The solid line marks the position of the right oblique fissure and the dotted line marks the approximate normal position of the oblique fissure

Comment

This case illustrates the vital link between a radiographer's image interpretation skills and their radiographic skills- it is largely about knowing when to repeat and when not to repeat. The original AP erect chest image demonstrates an abnormal pattern that you would not expect in a child who presents with a high temperature. Common pathologies and patterns of pathology occur commonly and they are looked for first. It was the combination of pattern recognition skills and image evaluation skills that led the radiographer to the conclusion that the patient's pathology had not been demonstrated correctly. The repeat AP erect chest allows for the easy recognition of RML and RUL disease- it is a pattern that is easily recognisable in a correctly positioned AP/PA chest.

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