Monitor (medicine)
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A monitor in the medical sense (also vital data monitor ) is a device or a combination of devices with which the vital parameters of a living being are measured and monitored.
Monitors are mainly used during anesthesia in operations, for critically ill patients in intensive care medicine , during examinations with sedation or for other clinical pictures that require continuous monitoring ( monitoring ). Mobile devices are available for use with emergency patients .
Depending on the application and legal requirements (e.g. minimum standards of monitoring during anesthesia), the devices are equipped with a different number of measurement parameters, but there are also modular devices that can be expanded by inserting appropriate parameter boxes.
parameter
- ECG for assessing the rhythm and heart rate (abbreviation ECG)
- Blood pressure measured either non-invasively via an upper arm or thigh cuff or invasively via an arterial catheter (a cannula in an artery ) in the radial or femoral artery (abbreviation NIBP or IBP)
- Oxygen saturation which is determined by means of a transcutaneous light sensor by means of absorption measurement, the procedure is called pulse oximetry (abbreviation SpO 2 )
- Body temperature , which is measured using temperature probes that can be inserted into the rectum or esophagus. There is also the possibility of temperature measurement using special indwelling urinary catheters that have an additional temperature probe.
If PiCCO monitoring is available, direct temperature measurement is also available. If the PiCCO system is present, the temperature in the blood is measured. (Abbreviation TEMP)
- Capnometry , the measurement of the carbon dioxide content in the exhaled air (abbreviation etCO 2 = end-tidal CO 2 )
If necessary, this monitoring can be extended to include additional parameters such as B. central venous pressure , intracranial pressure , measurement of cardiac output , pulse contour analysis ( PiCCO ), pulmonary arterial blood pressure values via a Swan-Ganz catheter or special forms of electroencephalography (EEG). In addition to the exhaled CO 2 (etCO 2 ), it is also possible to measure the CO 2 (tcpCO2) circulating in the blood . Various conclusions can be drawn about the gas exchange from the difference between the exhaled CO 2 and the CO 2 circulating in the blood . In order to avoid possible incorrect measurements, a regular blood gas analysis is necessary in addition to measuring the etCO 2 and tcpO2. The measurement of the exhaled CO 2 must also be divided into side stream (via a nasal cannula) and mainstream (e.g. in intubated patients). A side stream measurement is much more susceptible to failure than a mainstream measurement.
equipment
Depending on the intended use, different requirements are placed on the devices, so that various types are in use.
- In anesthesia, monitors are part of the anesthesia machine and are often permanently installed there. In intensive care units, the monitors are networked with one another and connected to a central monitoring station so that all important parameters of all patients can be called up from there.
- In emergency services , in intensive care or in the rescue helicopter to use smaller, more robust monitors or defibrillators , which also have a monitor function.
- Combinations of devices are available for monitoring during rehabilitation , which transmit the measured data to the monitoring center by radio transmission. This makes it possible to monitor the patient in a normal environment ( leisure activity ), so that more specific statements about everyday stress are possible.
There are also special devices that allow monitoring of acute problems in normal life, e.g. B. the transmission of vital functions via cellular phones to medical emergency centers. → Telemonitoring
Alarm limits, documentation of the values
If individually adjustable limit values are undercut or exceeded for the measured parameters or if disturbances such as cardiac arrhythmias are detected in a complex analysis, graduated optical and acoustic alarms can be triggered. These, like the measured parameters, can be transmitted to a central station and other vital signs monitors via a patient monitoring network (PMN). Doctors and nurses thus become aware of critical situations early on and can react quickly.
Almost all vital signs monitors now offer the option of transferring the measured parameters to a patient data management system (PDMS) via interfaces . This makes the documentation much easier and better.
documentation
In clinics, there is a need for complete recording of high-resolution medical data (vital parameters: e.g. heart rate, blood pressure and primary signals: e.g. EKG) from monitoring monitors. This enables a quick overview of the current status of the patient, taking the history into account. By recording over a longer period of time, individual events can be analyzed more precisely in retrospect. These data are used for current patient monitoring (e.g. in intensive care medicine ), for patient documentation and for data analysis in the field of medical research.
Special tools are used for this PC-based patient monitoring. The high-resolution vital data is made available to the hospital network via the serial interface of the monitor and recorded, visualized and saved on the PC. While patient monitors can only store vital data and primary signals for a certain period of time, long-term archiving is possible with such a system.