摘要:
Apparatus and methods for non-invasively determining cardiac output using partial re-breathing techniques are disclosed in which the apparatus is constructed with an instantaneously adjustable deadspace for accommodating differences in breathing capacities of various patients. The apparatus is constructed of inexpensive elements, including a single two-way valve which renders the apparatus very simple to use and inexpensive so that the unit may be readily disposable. The method of the invention provides a novel means of estimating cardiac output based on alveolar CO2 values rather than end-tidal CO2 values as previously practiced. A program for calculating cardiac output is also disclosed.
摘要:
A system (300) for measuring a metabolic parameter. The system includes an integrated airway adapter (20, 100, 200) capable of monitoring any combination of respiratory flow, O2 concentration, and concentrations of one or more of CO2, N2O, and an anesthetic agent in real time, breath by breath. Respiratory flow may be monitored with differential pressure flow meters under diverse inlet conditions through improved sensor configurations which minimize phase lag and dead space within the airway. Molecular oxygen concentration may be monitored by way of luminescence quenching techniques. Infrared absorption techniques may be used to monitor one or more of CO2, N2O, and anesthetic agents.
摘要:
An apparatus and method of using an end-tidal gas value taken from an non-intubated patient that includes measuring a plurality of gas concentration values, determining an end-tidal gas value from the gas concentration values, and reporting the end-tidal gas value for a breath as the greater of either: (a) a maximum gas concentration values observed during such a breath, or (b) the end-tidal gas value reported for a previous breath decreased by a maximum allowable breath-to-breath percent change.
摘要:
Methods and apparatus for enhancing reliability of, and monitoring, the operation of airway valves to enhance patient safety. Pneumatic control line pressure (positive or negative) for actuation of the airway valve may be specified at a given magnitude or within a selected range and monitored continuously. Reduced or excessive pressure may be compensated by actuation of a pressure source or a bleed valve, and monitoring may be effected so as to warn the user of any deviation from the range, or deviations of selected magnitudes or frequencies or a combination thereof. The inspired volume of CO2 may be monitored using air flow and CO2 sensing, with detection of excessive CO2 volume triggering a warning. Similarly, measured end-tidal or end-inspired CO2 or other appropriate measures of CO2 concentration may be employed as a warning trigger. Other driving energy sources for airway valves, and monitoring thereof, are also disclosed.
摘要:
A method for removing motion artifacts from devices for sensing bodily parameters and apparatus and system for effecting same. The method includes analyzing segments of measured data representing bodily parameters and possibly noise from motion artifacts. Each segment of measured data may correspond to a single light signal transmitted and detected after transmission or reflection through bodily tissue. Each data segment is frequency analyzed to determine up to three candidate peaks for further analysis. Each of the up to three candidate frequencies may be filtered and various parameters associated with each of the up to three candidate frequencies are calculated. The best frequency, if one exists, is determined by arbitrating the candidate frequencies using the calculated parameters according to predefined criteria. If a best frequency is found, a pulse rate and SpO2 may be output. If a best frequency is not found, other, conventional techniques for calculating pulse rate and Spo2 may be used. The above method may be applied to red and infrared pulse oximetry signals prior to calculating pulse rate and/or pulsatile blood oxygen concentration. Apparatus and systems disclosed are configured to perform methods disclosed according to the invention.
摘要:
A method of sampling one or more respiratory profile characteristics and monitoring a variety of respiratory profile parameters. The sampled respiratory characteristics include respiratory flow rate, respiratory pressure, and partial pressure of at least one constituent of a patient's respiration. The method detects patient breaths, determines whether each breath is a spontaneous breath or a ventilator-induced breath, and calculates various respiratory profile parameters based on the sampled measurements. The method displays the respiratory profile parameters in graphic and numeric forms. Preferably, the method allows a user to select the displayed respiratory profile parameters.
摘要:
A method of sampling one or more respiratory profile characteristics and monitoring a variety of respiratory profile parameters. The sampled respiratory characteristics include respiratory flow rate, respiratory pressure, and partial pressure of at least one constituent of a patient's respiration. The method detects patient breaths, determines whether each breath is a spontaneous breath or a ventilator-induced breath and calculates various respiratory profile parameters based on the sampled measurements. The method displays the respiratory profile parameters in graphic and numeric forms. Preferably, the method allows a user to select the displayed respiratory profile parameters.
摘要:
A patient interface for communicating fluids to and/or from a patient's nasal cavity and/or oral cavity is disclosed. In addition, a patient interface for fluid and physiological function monitoring proximate to the patient's nasal cavity and/or oral cavity is disclosed. An apnea monitor and a method for monitoring apnea are also disclosed.
摘要:
An apparatus and method for affording a re-breathing capability to a breathing circuit. The apparatus includes a valve that permits air flow through or re-breathing in the breathing circuit. A CO2 sensor and an air flow sensor detects CO2 a rate of air flow in the breathing circuit, respectively. A processor computes a parameter based on the CO2 waveform feature and a volumetric CO2 waveform feature based on signals from the air flow sensor and/or the CO2 sensor. An alarm is triggered when the parameter deviates from a selected magnitude. In a further embodiment, at least one parameter associated with an energy source for actuating the valve is monitored. Deviation of the value from at least one selected value of the at least one parameter is corrected.
摘要:
A method for removing motion artifacts from devices for sensing bodily parameters and apparatus and system for effecting same. The method includes analyzing segments of measured data representing bodily parameters and possibly noise from motion artifacts. Each segment of measured data may correspond to a single light signal transmitted and detected after transmission or reflection through bodily tissue. Each data segment is frequency analyzed to determine up to three candidate peaks for further analysis. Each of the up to three candidate frequencies may be filtered and various parameters associated with each of the up to three candidate frequencies are calculated. The best frequency, if one exists, is determined by arbitrating the candidate frequencies using the calculated parameters according to predefined criteria. If a best frequency is found, a pulse rate and SPO2 may be output. If a best frequency is not found, other, conventional techniques for calculating pulse rate and SpO2 may be used. The above method may be applied to red and infrared pulse oximetry signals prior to calculating pulse rate and/or pulsatile blood oxygen concentration. Apparatus and systems disclosed are configured to perform methods disclosed according to the invention.