Abstract: A medical device is described having a handle, a shaft coupled to the handle and an end effector coupled to the shaft. In one embodiment, the device includes an ultrasonic transducer and is arranged so that ultrasonic or electrical energy can be delivered to a vessel or tissue to be treated. Various novel sensing circuits are described to allow a measure of the drive signal to be measured and fed back to a controller. An active fuse circuit is also described for protecting one or more batteries of the device from an over-current situation.

Abstract: A medical device is described having a handle, a shaft coupled to the handle and an end effector coupled to the shaft. In one embodiment, the device includes an ultrasonic transducer and is arranged so that ultrasonic or electrical energy can be delivered to a vessel or tissue to be treated. Various novel sensing circuits are described to allow a measure of the drive signal to be measured and fed back to a controller. An active fuse circuit is also described for protecting one or more batteries of the device from an over-current situation.

Abstract: A medical device is described having a handle, a shaft coupled to the handle, an end effector coupled to the shaft and an ultrasonic transducer coupled to the end effector for delivering ultrasonic energy to tissue or a vessel to be treated. A drive circuit is provided for generating a drive signal that is applied to the ultrasonic transducer. In one embodiment, the drive circuit includes a resonant circuit and a controller that varies the period of the drive signal passed through the resonant circuit in order to control the power supplied to the ultrasonic transducer.

Abstract: A medical device is described having a handle, a shaft coupled to the handle and an end effector coupled to the shaft. In one embodiment, the device includes an ultrasonic transducer and is arranged so that ultrasonic or electrical energy can be delivered to a vessel or tissue to be treated. Various novel sensing circuits are described to allow a measure of the drive signal to be measured and fed back to a controller. An active fuse circuit is also described for protecting one or more batteries of the device from an over-current situation.

Abstract: This disclosure relates to medical fluid sensors and related systems and methods. In certain aspects, a nuclear magnetic resonance device includes a support frame, a first magnet connected to the support frame, a second magnet connected to the support frame in a manner such that the second magnet is disposed within the magnetic field of the first magnet and a magnetic attraction exists between the first magnet and the second magnet, and a spacer disposed between the first magnet and the second magnet. The spacer is configured to maintain a space between the first magnet and the second magnet.

Abstract: This disclosure relates to medical fluid sensors and related systems and methods. In some aspects, a circuit includes a radio frequency coil tuned to at least one frequency and at least one switching circuit directly connected to the radio frequency coil. The radio frequency coil is characterized by a high impedance.

Abstract: This disclosure relates to medical fluid sensors and related systems and methods. In certain aspects, a method includes reading an indicia of a medical fluid cartridge to determine a volume of a fluid passageway of the medical fluid cartridge indicated by the indicia, receiving radio frequency energy generated by excited atoms in medical fluid in the fluid passageway of the medical fluid cartridge, and determining a concentration of a substance in the medical fluid based on the determined volume of the fluid passageway of the medical fluid cartridge indicated by the indicia and the received radio frequency energy generated by the excited atoms in the medical fluid in the fluid passageway of the medical fluid cartridge.

Abstract: This disclosure relates to medical fluid sensors and related systems and methods. In certain aspects, a method includes reading an indicia of a medical fluid cartridge to determine a volume of a fluid passageway of the medical fluid cartridge indicated by the indicia, receiving radio frequency energy generated by excited atoms in medical fluid in the fluid passageway of the medical fluid cartridge, and determining a concentration of a substance in the medical fluid based on the determined volume of the fluid passageway of the medical fluid cartridge indicated by the indicia and the received radio frequency energy generated by the excited atoms in the medical fluid in the fluid passageway of the medical fluid cartridge.

Abstract: A medical device is described having a handle, a shaft coupled to the handle and an end effector coupled to the shaft. In one embodiment, the device includes an ultrasonic transducer and is arranged so that ultrasonic or electrical energy can be delivered to a vessel or tissue to be treated. Various novel sensing circuits are described to allow a measure of the drive signal to be measured and fed back to a controller. An active fuse circuit is also described for protecting one or more batteries of the device from an over-current situation.

Abstract: A medical device is described having a handle, a shaft coupled to the handle, an end effector coupled to the shaft and an ultrasonic transducer coupled to the end effector for delivering ultrasonic energy to tissue or a vessel to be treated. A drive circuit is provided for generating a drive signal that is applied to the ultrasonic transducer. In one embodiment, the drive circuit includes a resonant circuit and a controller that varies the period of the drive signal passed through the resonant circuit in order to control the power supplied to the ultrasonic transducer.

Abstract: This disclosure relates to medical fluid sensors and related systems and methods. In certain aspects, a method includes reading an indicia of a medical fluid cartridge to determine a volume of a fluid passageway of the medical fluid cartridge indicated by the indicia, receiving radio frequency energy generated by excited atoms in medical fluid in the fluid passageway of the medical fluid cartridge, and determining a concentration of a substance in the medical fluid based on the determined volume of the fluid passageway of the medical fluid cartridge indicated by the indicia and the received radio frequency energy generated by the excited atoms in the medical fluid in the fluid passageway of the medical fluid cartridge.

Abstract: This disclosure relates to medical fluid sensors and related systems and methods. In some aspects, a circuit includes a radio frequency coil tuned to at least one frequency and at least one switching circuit directly connected to the radio frequency coil. The radio frequency coil is characterized by a high impedance.

Abstract: This disclosure relates to medical fluid sensors and related systems and methods. In certain aspects, a nuclear magnetic resonance device includes a support frame, a first magnet connected to the support frame, a second magnet connected to the support frame in a manner such that the second magnet is disposed within the magnetic field of the first magnet and a magnetic attraction exists between the first magnet and the second magnet, and a spacer disposed between the first magnet and the second magnet. The spacer is configured to maintain a space between the first magnet and the second magnet.