Abstract
Aim
To demonstrate the effect of location of the split of the plaster on the raised intercompartmental pressure in the volar and dorsal compartments.
Methods
Artificial forearm skeleton was used along with two half litre saline bags on ether side representing volar and dorsal forearm compartment. A single layer of cotton wool with half width overlap was applied followed by three rolls of 10cm x 2.5 m plaster of paris. This was then left to dry for four hours. Both the saline bags had an eighteen gauge catheter inserted that was connected to the central venous pressure monitoring line on the anaesthetic machine. Baseline pressure in mmHg was recorded. Normal saline was then injected in both the bags so as to raise the pressure to 50 mmHg in each compartment. POP cast was then split, spread and then the wool was cut down to the saline bags while continually monitoring the pressures. The respective change in the pressure at the end of each step was recorded. Six simulated forearm models had dorsal splits and an equal number had volar splits. The effect of the site and various steps of splitting on the drop in respective compartment pressures was compared.
Results
The mean drop in pressure was 24mmHg after all the steps of splitting were completed. This was independent of the site of the split of the cast. The mean drop in ICP after spreading the cast was statistically significant (P=0.01) when compared to cutting cast and cutting wool.
Conclusions
Split in cast has similar effect on both, same side and opposite side, compartments in reducing the ICP. Spreading of the cast is the most effective step in reducing the raised ICP and should not be missed.
