An apparatus for monitoring EMG signals of a patient's laryngeal muscles includes an endotracheal tube having an exterior surface and a first location configured to be positioned at the patient's vocal folds. A first electrode is formed on the exterior surface of the endotracheal tube substantially below the first location to receive EMG signals primarily from below the vocal folds. A second electrode is formed on the exterior surface of the endotracheal tube substantially above the first location to receive EMG signals primarily from above the vocal folds. The first and second electrodes are configured to receive the EMG signals from the laryngeal muscles when the endotracheal tube is placed in a trachea of the patient.

Methods, systems and devices for estimating the position and orientation of an invasive surgical devices, for example, a catheter guidewire or endoscope, surgical catheter, or self-guided electrophysiology catheter, relative to a reference frame, are described. An example system comprises one or more permanent magnets mounted on the surgical device, a plurality of magnetometer sensors at fixed location providing a reference frame that are configured to perform magnetic field measurements of the direct current superposition field of the permanent magnets, and computational means for receiving the input signals and calculating the position and orientation of the permanent magnets mounted on the surgical device.

There is provided a system for monitoring a heart of a subject and monitoring impedance-related parameters, comprising: a feeding tube, an electrode disposed(s) on a distal end of the feeding tube, a controller that performs, while the feeding tube is in located in an esophagus and feeding is delivered to a subject via the feeding tube, in a plurality of iterations: continuously measuring voltage at the electrode(s) of the feeding tube, applying alternating current(s) between the electrode(s) of the feeding tube and at least one other electrode, computing impedance measurement(s) from the electrode(s) of the feeding tube according to the applied alternating current(s) and the measured voltage, computing impedance-related parameter(s) based on the impedance measurement(s), terminating the application of the alternating current(s), obtaining an electrocardiogram (ECG) measurement based on the voltage measured at the electrode(s) of the feeding tube, and providing the impedance-related parameter(s) and the ECG measurement.

A method of estimating a spatial relationship between at least a part of a patient esophagus and a heart chamber, including: measuring at least one electric parameter at one or more positions within the heart chamber to obtain measured values; and estimating the spatial relationship based on the measured values.

A method of estimating a spatial relationship between at least a part of a patient esophagus and a heart chamber, including: measuring at least one electric parameter at one or more positions within the heart chamber to obtain measured values; and estimating the spatial relationship based on the measured values.

A method includes, receiving from a calibration probe multiple data points acquired in an organ of a patient, each data point including (i) a respective position of the calibration probe, and (ii) a respective set of electrical values indicative of respective impedances between the position and multiple electrodes attached externally to the patient. A mapping between sets of the electrical values and respective positions in the organ is constructed, by performing for each received data point: if the mapping already contains one or more existing data points in a predefined vicinity of the data point, the one or more existing data points are adjusted responsively to the received data point, and if the predefined vicinity does not contain any existing data points, the received data point is added to the mapping. A position of a medical probe is subsequently tracked in the organ using the mapping.

A method includes, receiving from a calibration probe multiple data points acquired in an organ of a patient, each data point including (i) a respective position of the calibration probe, and (ii) a respective set of electrical values indicative of respective impedances between the position and multiple electrodes attached externally to the patient. A mapping between sets of the electrical values and respective positions in the organ is constructed, by performing for each received data point: if the mapping already contains one or more existing data points in a predefined vicinity of the data point, the one or more existing data points are adjusted responsively to the received data point, and if the predefined vicinity does not contain any existing data points, the received data point is added to the mapping. A position of a medical probe is subsequently tracked in the organ using the mapping.

In some embodiments, a body cavity shape of a subject is reconstructed based on intrabody measurements of voltages by an intrabody probe (for example, a catheter probe) moving within a plurality of differently-oriented electromagnetic fields crossing the body cavity. In some embodiments, the method uses distances between electrodes as a spatially calibrated ruler. Positions of measurements made with the intrabody probe in different positions are optionally related by using spatial coherence of the measured electromagnetic fields as a constraint. Optionally, reconstruction is performed without using a detailed reference (image or simulation) describing the body cavity shape. Optionally, reconstruction uses further information to refine and/or constrain the reconstruction; for example: images, simulations, additional electromagnetic fields, and/or measurements characteristic of body cavity landmarks. Optionally, reconstruction accounts for time-dependent cavity shape changes, for example, phasic changes (e.g., heartbeat and/or respiration), and/or changes in states such as subject hydration, edema, and/or heart rate.

In accordance with some non-limiting examples of the disclosed subject matter, an ingestible system configured to acquire physiological information from an interior of a subject is provided, comprising a substrate and at least one physiological sensor. The at least one physiological sensor can be coupled to the substrate and configured to capture physiological data from at least one of an internal area or an orientation in a digestive tract of the subject. The system can include a controller coupled to the substrate and configured to receive the physiological data and prepare the physiological data for one of transmission from the subject or analysis of the physiological data. The substrate, including the at least one physiological sensor and the controller coupled thereto can be configured to self-orient within the digestive tract of the subject, during ingestion of the system by the subject. The substrate can additionally orient the at least one physiological sensor in the at least one of the internal area or the orientation in the digestive tract of the subject.

In accordance with some non-limiting examples of the disclosed subject matter, an ingestible system configured to acquire physiological information from an interior of a subject is provided, comprising a substrate and at least one physiological sensor. The at least one physiological sensor can be coupled to the substrate and configured to capture physiological data from at least one of an internal area or an orientation in a digestive tract of the subject. The system can include a controller coupled to the substrate and configured to receive the physiological data and prepare the physiological data for one of transmission from the subject or analysis of the physiological data. The substrate, including the at least one physiological sensor and the controller coupled thereto can be configured to self-orient within the digestive tract of the subject, during ingestion of the system by the subject. The substrate can additionally orient the at least one physiological sensor in the at least one of the internal area or the orientation in the digestive tract of the subject.