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European Society of Anaesthesiology
ESA Poster: Japanese Version
Effects of IH Cookers on SCS and Protective Clothing for SCS Patients
Hiroshi Igarashi, Yoko Kume, Shigehito Sato, Genichi Matsumoto, Hideki Matsui
Department of Anesthesiology and Resuscitation, Hamamatsu University School of Medicine / Osaka Research Institute of Industrial Science and Technology / Medical Aid Co., Ltd.
Background
Spinal Cord Stimulation systems (SCS) are widely used to treat chronic pain patients. Meanwhile, electrical appliances such as IH cookers that emit strong magnetic fields have also become widespread. While the effects of such appliances on pacemakers have been widely reported, little is known about their effects on SCS. This report investigates the influence of IH cookers on SCS.
Case
A 59-year-old female patient. She developed vasospastic angina at age 48 and began SCS therapy at 53. After purchasing an IH cooker at 59, she complained of severe discomfort in the neck and back each time it was used, which disappeared when she moved two meters away from the cooker.
Materials and Methods
To evaluate the effects of IH cookers on SCS, two experiments were conducted:
Experiment 1
We evaluated the effect of IH cookers and the effectiveness of protective clothing using a phantom model and oscilloscope. The phantom was a resin hollow body filled with 0.18% saline to mimic human electrical resistance (Irnich model, Fig. 1). The SCS was placed in the same location as it would be in a patient. With the IH cooker output at 1350W, we brought it near the phantom, with and without protective clothing, and measured voltage generated in the SCS (Fig. 2). The protective clothing used was one commonly available in Japan for pacemakers.
Experiment 2
This experiment was approved by the ethics committee and conducted with patient consent. The patient tested three types of clothing: (1) standard pacemaker shield, (2)(3) improved types (Fig. 3). With three postures (upright, forward-bent, backward), the IH cooker was set to 1530W and run for 10 minutes or until symptoms appeared (Fig. 4).
Results 1
When the IH cooker was brought close to the SCS in the phantom, small wave-like noise appeared on the oscilloscope. These waves had varying frequencies overlaid on a base wave of 60Hz—matching local AC frequency. When shielded with protective clothing, the wave disappeared.
Results 2
| Patient Posture | Upright, Facing Forward | Forward-Bent | Upright, Backward |
|---|---|---|---|
| (1) Pacemaker Protective Garment | Symptoms after 2.5 min * | Symptoms after 30 sec * | No effect |
| (2) Improved Garment (Single long shield) | Symptoms after 3 min ** | Symptoms after 1 min ** | Symptoms after 1 min ** |
| (3) Improved Garment (Dual shield) | No symptoms for 10 min *** | No symptoms for 10 min *** | No symptoms for 10 min *** |
Figure 1: Effectiveness of protective garments against IH cookers for SCS patients
* Chest discomfort, ** Pressure on left shoulder, *** No symptoms
Discussion
In Experiment 1, current was induced in the SCS by the IH cooker, but no malfunction occurred. The discomfort was assumed to result from electromagnetic induction stimulating the spinal cord. To prevent this, shielding the lead loop portion of the SCS system was found to be essential (Fig. 5).
Experiment 2 showed the pacemaker garment was insufficient. The single long shield improved performance but didn’t fully block induction, especially from behind. When the garment was redesigned with two shields, one covering the chest and one the back left, the patient reported no symptoms. Further studies will be conducted to verify effectiveness.
Conclusion
The IH cooker did not affect the SCS generator directly, but had an electromagnetic effect on the coiled SCS leads. Proper protective clothing successfully blocked this influence, preventing discomfort and ensuring patient safety.
References
1) Irnich, W.: Interference in pacemakers. Pacing Clin Electrophysiol. 1984 Nov;7(6 Pt 1):1021-48