New phase-lock tracking instrument for foetal breathing monitoring

An instrument has been developed that allows foetal breathing movements to be recorded with a laboratory resolution of about 0·06 mm. The new tracking scheme is described in addition to the complete instrument incorporating a number of these tracking units for multichannel movement monitoring. The multiple tracking scheme is implemented by adapting a commercial real-time array and building a custom or special instrument to process the signals. The instrument is capable of simultaneously tracking up to six separate echo complexes selected on an electronically-switched real-time B-scan image of the foetus. It therefore can provide any permutation of three channels of differential movement at the same time. Early clinical results obtained using the new instrument are presented.