Plaster of Paris (POP) slabs

Used to immobilise injured limb or suspected fracture during transport, while waiting for x-ray, until swelling lessens. Can be used as main support for soft tissue injuries

Attention

  • Examine carefully to accurately diagnose injury and need for immobilisation
  • Give pain relief if needed before positioning limb, putting on plaster
  • Slabs need to be wide enough to fit around curve of limb like a shallow bowl, but not cover more than ⅔ of limb circumference — Figure 10.45

Figure 10.45  

  • Check circulation and sensation — after putting on plaster check hands/fingers, feet/toes for colour, warmth, sensation, movement, capillary refill, peripheral pulses — F 7.1.
    • If any not normal — take slab off straight away
  • If person returns to clinic complaining of pain and/or fingers/toes show signs of poor blood or nerve sensation — take slab off straight away

What you need

  • A helper
  • Plastic aprons — messy procedure, protect person's and your clothing 
  • Blueys or plastic covers
  • Wide bowl or bucket deep enough for plaster bandage to be fully submerged in water — line with plastic bag
  • Cool or slightly warm (tepid) water 
    • Do not use hot water — plaster will set too fast, may cause thermal burns
    • Do not use very cold water — plaster will set too slowly
  • Cotton or wool underlay (also called plaster wool)
  • Crepe bandages (size depends on size of limb), tape
  • Strong scissors or plaster shears
  • Plaster rolls
    • 5cm for hands, 7.5cm for lower arms, 10cm for upper arms and legs
    • Need 5–10 layers of plaster depending on age and size — provide support but keep light 

What you do

  • Cover area around work site with blueys/plastic, put water nearby
  • Put on protective aprons 

Protect skin

  • Put on wool or cotton underlay 
    • Lay gently around limb — Figure 10.46. Do not pull tight, make creases or ridges
    • Each layer should overlap previous by about half. Usually 2 layers for arm, 3–4 layers for leg
    • Tear to shape around joints
    • Use 2 extra layers to protect joints or prominent areas 
    • Bandage 5cm further than area plaster will cover, to fold back over rough ends

Figure 10.46  

Position limb

  • Make sure limb in right position before you start to plaster
  • Keep limb in right position until plaster dries to avoid making creases that can damage skin, cause pressure areas
  • Assistant can be used to help support end of limb (distally), if needed

Measure and cut slab

  • Measure length of slab with crepe bandage or tape measure — Figure 10.47
    • Measure uninjured limb if injury very painful
    • Allow extra 10% as plaster bandage shrinks when wet

Figure 10.47  

Figure 10.48  

  • Lay dry plaster bandage on flat surface to measured length, layer backward and forward until right number of layers (usually 5–10) — Figure 10.48
  • If plaster bandage not wide enough for limb — layers can be fanned out to widen slab — Figure 10.49
    • Fanning layers weakens slab, so use extra layers but no more than 20 — more than 20 can cause burns

Figure 10.49  

  • Hold slab by edges to stop damage to plaster
  • Fold plaster or cut plaster to accommodate thumb if needed
  • Hold slab against limb to check size before putting in water

Wet the slab

  • Lift slab by holding one end, lower into water until whole slab wet — Figure 10.50
  • OR Hold long slabs (eg full arm) in concertina shape so they fit in water bowl — Figure 10.51

Figure 10.50  

Figure 10.51  

  • Hold under water until bubbles stop
  • Lift slab out by holding upright — Figure 10.52
  • Run 2 fingers down length to squeeze out excess water

Figure 10.52  

Apply slab

  • Handle wet or dry plaster bandage with care or it will become damaged and weak
  • Check position of limb, fingers/toes. Ask helper to hold, if needed
  • Lay slab. Start at knuckles/wrist/toes (extremities) and go toward body — Figure 10.53

Figure 10.53  

  • Use flat of your hands to shape around joints and smooth as you go. Smooth from fingers/hands or toes/feet toward body
    • Do not use your fingers — can make dents in plaster that press into person's flesh
  • Warn person slab will feel quite hot as it dries
  • Fold ends of underlay back over ends of slab to protect skin
  • Bandage around slab and limb with crepe bandage to keep slab firmly in place
  • Bandage from end of limb/slab toward body
  • Hold limb in correct position for 3–5 minutes. Plaster will reach full strength in 24–48 hours
  • Put arm in sling or keep leg lifted (eg on pillows)
  • Clear away equipment
    • Never tip POP waste down drain
    • Empty used water on garden, throw away POP waste left in bottom of bag lining water bowl/bucket
  • Check circulation and sensation
  • Organise specialist review

Types of slabs 

  • All plaster slabs are applied on the side with the break — to support and immobilise
  • Make room for the thumb in arm slabs — see
    • Folding slab to accommodate thumb 
    • OR Cutting slab to accommodate thumb

Folding slab to accommodate thumb

  • Measure and layer plaster to make slab
  • Fold down corner of slab — Figure 10.54

Figure 10.54  

Hold fold in place while lowering plaster into water — Figure 10.55

Figure 10.55  

  • Lay plaster on arm starting at knuckles with folded side on the thumb side — Figure 10.54
  • Smooth plaster around thumb and across knuckles
    • For scaphoid bone or first metacarpal fracture — apply plaster around joint at base of thumb so it doesn't move but middle joint is free and can bend
    • For Colles or distal forearm fractures — thumb joint should move freely. Thumb and little finger can meet — Figure 10.56

Figure 10.56  

Cutting slab to accommodate thumb

Lower arm slab — scaphoid

Used for fracture of scaphoid bone or first metacarpal that hasn't moved out of alignment (not displaced). Also for soft tissue injury to/around thumb

  • Put on underlay — around thumb, across palm to middle of elbow
    • Put 2 extra layers around thumb
  • Measure inside of arm from centre of palm to 3 finger widths below crease of elbow
    • Elbow joint must move freely
  • Make slab and cut to fit around thumb and clear knuckles — Figure 10.57

Figure 10.57  

  • Put arm and hand/fingers straight, flex wrist 20° — ask person to hold bandage as shown — Figure 10.58

Figure 10.58  

  • Joint at base of thumb shouldn’t move but middle joint is free
  • Thumb and 3rd finger should just meet — Figure 10.59

Figure 10.59  

Lower arm slab — radial or universal

Used for Colles or distal forearm fractures

  • Put on underlay — from middle of fingers to middle of elbow
    • Put 2 extra layers around wrist and thumb
  • Measure from base of knuckle joints to 3 finger widths below elbow crease — elbow joint must move freely
  • Make slab and cut to accommodate thumb — Figure 10.60 or Figure 10.61

Figure 10.60  

Figure 10.61  

  • Position arm, hand, fingers straight
  • Lay slab on back of forearm from base of knuckles to 3 finger widths below elbow crease
  • With slab applied
    • Thumb joint should be able to move freely, thumb and little finger able to touch — Figure 10.56
    • All fingers should be able to bend

Full arm slab

Used for fracture of middle and proximal thirds of radius or ulnar or lower humerus that hasn't moved out of alignment (not displaced)

  • Person sits in comfortable chair
  • Get helper to hold person’s elbow at 90°, fingers in air — Figure 10.62

Figure 10.62  

  • Put on underlay — from fingers to 3 finger widths below armpit, and another layer from tips of fingers to elbow
    • Put extra layer around elbow
    • Put 2 extra layers around wrist
  • Measure from centre of palm, around outside of elbow, to 3 finger widths below armpit — Figure 10.63

Figure 10.63  

Lower leg slab

Used for fracture of distal tibia, fibula, tarsus or proximal metatarsals that hasn't moved out of alignment (not displaced). Also used for soft tissue injuries to lower leg or foot — Figure 10.64

Figure 10.64  

  • Person lies on bed on stomach with knee and ankle flexed (bent) to 90° — Figure 10.65
  • OR Person sits up or lies back with injured foot over edge of bed and ankle flexed to 90°. Use rolled towel to flex knee slightly (15–20°) on injured side — Figure 10.66

Figure 10.65  

Figure 10.66  

  • Put on cotton or wool underlay — from tip of toes to middle of knee
    • Put 2 extra layers around ankle
  • Measure back of leg from base of toes to 3 finger widths below base of knee — Figure 10.67

Figure 10.67  

  • Make slab. Fan plaster if legs large, or only narrow plaster rolls available — but do not use more than 20 layers
  • Check ankle at 90° and hold in position for several minutes until plaster sets — Figure 10.64