The semiconductor laser element comprises, from bottom to top, the p-AlxGa1xAs upper clad layer, p-AlyGa1yAs resistance control layer, and p-GaAs cap layer. Different emitted audible signals are sequentially emitted in response to receiving an activation signal. The circuit also includes a filter with a capacitive-summing junction to equalize the signals. The nasogastric tube comprises a tube having one or more interior bores or lumina and a guide element capture structure.