CL Ultrasound Transducer: Wireless Technology for Continuous, Flexible, and Reliable Fetal Monitoring
The CL Ultrasound Transducer (Ref. 866076) is a next-generation ultrasound sensor developed by Philips for the Avalon fetal monitoring systems. This wireless transducer is part of the Avalon CL system, allowing pregnant patients to benefit from continuous fetal heart rate (FHR) monitoring while maintaining complete mobility, including during water immersion. This device represents a major technological advancement in perinatal monitoring, combining comfort, safety, and efficiency.
Unlike traditional transducers, which transmit analog signals to the monitor for processing, the CL Ultrasound Transducer contains its own microprocessor and signal processing unit. This Smart Transducer technology allows the signal to be converted and processed directly at the source, and then sent digitally to the Avalon monitor. This process enhances signal quality, reduces electromagnetic interference, and significantly improves system reliability. Its modular design also allows multiple transducers to be connected to a single monitor without any drop in performance—even when monitoring multiple fetuses (up to three).
The ultrasound sensor features an optimized crystal layout with seven crystals (six arranged around the edge and one in the center) placed in equilateral triangle formations. This geometry ensures uniform signal coverage, improves the accuracy of cardiac detection, and minimizes the need for repositioning the transducer. Compared to systems that use more crystals in non-uniform layouts, Philips’ approach offers the ideal balance between performance, cost, and reliability.
One of the key features of the CL Ultrasound Transducer is its built-in Finder LED—a blue light that activates to identify the transducer in use. This function is especially useful when repositioning is needed, particularly in multiple pregnancy monitoring scenarios. The Avalon monitor automatically assigns a channel (FHR1, FHR2, FHR3) to each transducer, regardless of which port is used, simplifying setup and minimizing human error.
The transducer supports Cross-Channel Verification (CCV), which compares FHR signals in real time and alerts the clinician if any suspicious overlap between maternal and fetal heart rates is detected. This critical safety feature helps reduce the risk of misinterpretation and potential diagnostic errors.
Additionally, the CL Ultrasound Transducer supports Fetal Movement Profile (FMP), an exclusive Philips parameter that evaluates both fetal heart rate and gross body movements simultaneously. This comprehensive monitoring capability is especially beneficial in high-risk pregnancies and has been shown to reduce unnecessary secondary testing. FMP contributes to better cost-effectiveness and improved clinical outcomes.
This transducer also features an ergonomic design for enhanced maternal comfort, is fully waterproof, and is compatible with all Avalon monitors (FM20, FM30, FM40, FM50), provided the software version is J.3x.xx or later. By enabling a more mobile, safer, and more comfortable fetal monitoring environment, the CL Ultrasound Transducer is an essential tool for maternity units that support physiological or active labor.
