Bring life back to your mannequin! - Easy fix for Gaumard in Pulseless Electrical Activity
By SimGHOSTS President Dr Scott Crawford
Has your Gaumard Hal or Susie lost its pulses? No, not because it was part of the scenario, but because of a mechanical failure. Gaumard uses a pneumatic system for pulse generation it its high-fidelity mannequins. This pneumatic pulse is transmitted through a series of 1/16” tubes to provide pulses to the carotid, brachial, radial, and femoral sites for palpation by learners. The system routes this smaller tubing through the arms and torso, even supplying a small pressure regulator (that is not needed) to give a realistic decrease in pulse strength at the distal pulse sites (see figure 1). This thin plastic tubing is adapted into an 1/8” latex tubing section with sufficient elasticity so that it can transmit the pulse wave to the learner through the overlying silicon skin.
Figure 1 - Pressure regulator from Gaumard Hal arm
Many simulation centers have noted a loss of pulses at one or more sites on their mannequins. This does not mean you need to give epinephrine or replace the mannequin. The terminal pulse detection point where the latex tubing exists must be plugged in order to allow the pressure wave to be transmitted through the wall of the latex tubing. This is accomplished at the factory by a small plastic cap inserted into the end of the latex tubing. This cap has been known to fall out or get disconnected during standard use. Any plastic or wooden cap should accomplish this same purpose. This diagnosis can be suspected if your Gaumard mannequin has pulses in some parts of the mannequin, but not others, and may be associated with a “whooshing” sound heard near the expected pulse points.
The carotid pulses are accessible by removing the superficial neck skin and finding the latex tubing routed up through a hole in the deep section of silicon attached to the face of the mannequin. The tubing is then routed across this section of skin and then down through a second hole ~2 cm away. The tubing cap previously described must be placed inside the latex tubing on the underside of this silicon layer, below the upper hole.
Figure 2 - Gaumard Hal elbow pulse connection
The arm sections can be more difficult to evaluate because the skin on the arms is tighter and held in place by elastic forces, and not Velcro, as is the case on the neck. The elbow articulation must be disconnected by using two Allen wrenches. The tubing and electronics bundle are routed through this space and secured inside a section of heat shrink tubing (Figure 2). Once the elbow is separated, the upper arm or lower arm skin can be carefully stretched and pulled down to uncover the hard plastic arm section that houses the pulse tubing and electronics. A systematic approach of evaluating the proximal pulse tubing before trying to fix the distal areas is recommended. The hand skin can be very tight and use of silicone lubricant can assist with both removal and re-application. Once removed, looking into the distal hand opening should reveal a loop of wire (the radio frequency detector) and the tubing for radial pulse detection. Again, because the tubing is routed from inside the arm, out for palpation, and then back inside for plugging, access to place a new plug must occur from the inside of the hand’s hard plastic shell. This is difficult due to the size of the opening offered, but the latex tubing is elastic enough that it can be pulled (carefully) outside of the plastic casing using a pair of pliers or surgical forceps. Once pulled outside of the plastic hand casing, a new plug can be applied. A small dot of superglue was applied during the repair shown in Figure 3 to decrease the chances of a repeat pulse failure.
|Figure 3 - Gaumard- Hal arm with circle showing radial pulse plug||
Figure 4 - Technique for re-applying the arm skin onGaumard Hal. Silicon spray was applied prior to application.
Figure 4 shows a successful technique for re-applying the hand/forearm skin to the mannequin. Place the hand section on a firm surface with the elbow attachment down. Have an assistant to help stabilize the arm. Using baby powder or silicon spray lubricant on the hard plastic arm section, carefully stretch and pull the hand and forearm silicon skin down over the frame. This is the same technique required for replacing the latex tubing used for IV starts if that skill is performed frequently on your mannequins.