In medicine,monitoring is the observation of a disease, condition or one or several medical parameters over time.

It can be performed by continuously measuring certain parameters by using amedical monitor (for example, by continuously measuringvital signs by a bedside monitor), and/or by repeatedly performingmedical tests (such asblood glucose monitoring with aglucose meter in people withdiabetes mellitus).

Transmitting data from a monitor to a distant monitoring station is known astelemetry orbiotelemetry.

Monitoring can be classified by the target of interest, including:

• Cardiac monitoring, which generally refers to continuouselectrocardiography with assessment of the patient's condition relative to their cardiac rhythm. A small monitor worn by an ambulatory patient for this purpose is known as aHolter monitor. Cardiac monitoring can also involvecardiac output monitoring via an invasiveSwan-Ganz catheter.
• Hemodynamic monitoring, which monitors theblood pressure andblood flow within the circulatory system. Blood pressure can be measured either invasively through an inserted blood pressuretransducer assembly, or noninvasively with an inflatable blood pressure cuff.
• Respiratory monitoring, such as:
  • Pulse oximetry which involves measurement of the saturated percentage ofoxygen in theblood, referred to as SpO2, and measured by aninfrared finger cuff
  • Capnography, which involves CO₂ measurements, referred to asEtCO2 or end-tidalcarbon dioxide concentration. The respiratory rate monitored as such is called AWRR orairway respiratory rate)
  • Respiratory rate monitoring through a thoracic transducer belt, an ECG channel or via capnography
• Neurological monitoring, such as ofintracranial pressure. Also, there are special patient monitors which incorporate the monitoring of brain waves (electroencephalography), gas anesthetic concentrations,bispectral index (BIS), etc. They are usually incorporated into anesthesia machines. Inneurosurgery intensive care units, brain EEG monitors have a larger multichannel capability and can monitor other physiological events, as well.
• Blood glucose monitoring
• Childbirth monitoring
• Body temperature monitoring through anadhesive pad containing athermoelectric transducer.
• Cancer therapy monitoring throughcirculating tumor cells^[1]

Monitoring ofvital parameters can include several of the ones mentioned above, and most commonly include at leastblood pressure andheart rate, and preferably alsopulse oximetry andrespiratory rate. Multimodal monitors that simultaneously measure and display the relevant vital parameters are commonly integrated into the bedside monitors incritical care units, and theanesthetic machines inoperating rooms. These allow for continuous monitoring of a patient, with medical staff being continuously informed of the changes in general condition of a patient. Some monitors can even warn of pending fatalcardiac conditions before visible signs are noticeable to clinical staff, such asatrial fibrillation orpremature ventricular contraction (PVC).

Amedical monitor orphysiological monitor is amedical device used for monitoring. It can consist of one or moresensors, processing components,display devices (which are sometimes in themselves called "monitors"), as well as communication links for displaying or recording the results elsewhere through a monitoring network.^{[citation needed]}

Sensors of medical monitors includebiosensors and mechanical sensors. For example, photodiode is used in pulse oximetry, Pressure sensor used in Non Invasive blood pressure measurement.

The translating component of medical monitors is responsible for converting the signals from the sensors to a format that can be shown on the display device or transferred to an external display or recording device.

Physiological data are displayed continuously on aCRT,LED orLCD screen asdata channels along the time axis. They may be accompanied bynumerical readouts of computed parameters on the original data, such as maximum, minimum and average values, pulse and respiratory frequencies, and so on.^{[citation needed]}

Besides the tracings of physiological parameters along time (X axis), digital medical displays have automatednumeric readouts of the peak and/or average parameters displayed on the screen.

Modern medical display devices commonly usedigital signal processing (DSP), which has the advantages ofminiaturization,portability, and multi-parameter displays that can track many different vital signs at once.^{[citation needed]}

Oldanalog patient displays, in contrast, were based onoscilloscopes, and had one channel only, usually reserved for electrocardiographic monitoring (ECG). Therefore, medical monitors tended to be highly specialized. One monitor would track a patient'sblood pressure, while another would measurepulse oximetry, another the ECG. Later analog models had a second or third channel displayed on the same screen, usually to monitorrespiration movements andblood pressure. These machines were widely used and saved many lives, but they had several restrictions, including sensitivity toelectrical interference, base level fluctuations and absence of numeric readouts and alarms.^{[citation needed]}

Several models of multi-parameter monitors are networkable, i.e., they can send their output to a central ICU monitoring station, where a single staff member can observe and respond to several bedside monitors simultaneously.Ambulatory telemetry can also be achieved by portable, battery-operated models which are carried by the patient and which transmit their data via awireless data connection.

Digital monitoring has created the possibility, which is being fully developed, of integrating the physiological data from the patient monitoring networks into the emerging hospitalelectronic health record and digital charting systems, using appropriatehealth care standards which have been developed for this purpose by organizations such asIEEE andHL7. This newer method of charting patient data reduces the likelihood of human documentation error and will eventually reduce overall paper consumption. In addition,automated ECG interpretation incorporates diagnostic codes automatically into the charts. Medical monitor'sembedded software can take care of the data coding according to these standards and send messages to the medical records application, which decodes them and incorporates the data into the adequate fields.

Long-distance connectivity can avail fortelemedicine, which involves provision ofclinical health care at a distance.

A medical monitor can also have the function to produce an alarm (such as using audible signals) to alert the staff when certain criteria are set, such as when some parameter exceeds of falls the level limits.

An entirely new scope is opened with mobile carried monitors, even such in sub-skin carriage. This class of monitors delivers information gathered in body-area networking (BAN) to e.g.smart phones and implementedautonomous agents.

Monitoring of clinical parameters is primarily intended to detect changes (or absence of changes) in the clinical status of an individual. For example, the parameter ofoxygen saturation is usually monitored to detect changes inrespiratory capability of an individual.

When monitoring a clinical parameters, differences between test results (or values of a continuously monitored parameter after a time interval) can reflect either (or both) an actual change in the status of the condition or atest-retest variability of the test method.

In practice, the possibility that a difference is due to test-retest variability can almost certainly be excluded if the difference is larger than a predefined "critical difference". This "critical difference" (CD) is calculated as:^[2]

${\displaystyle CD=K\times \sqrt{C{V}_a^2+C{V}_i^2}}$

, where:^[2]

• K, is a factor dependent on the preferred probability level. Usually, it is set at 2.77, which reflects a 95%prediction interval, in which case there is less than 5% probability that a test result would become higher or lower than the critical difference by test-retest variability in the absence of other factors.
• CV_a is the analytical variation
• CV_i is theintra-individual variability

For example, if a patient has a hemoglobin level of 100 g/L, the analytical variation (CV_a) is 1.8% and the intra-individual variabilityCV_i is 2.2%, then the critical difference is 8.1 g/L. Thus, for changes of less than 8 g/L since a previous test, the possibility that the change is completely caused by test-retest variability may need to be considered in addition to considering effects of, for example, diseases or treatments.

Critical differences for other tests include early morning urinary albumin concentration, with a critical difference of 40%.^[2]

In a clinical laboratory, adelta check is alaboratory quality control method that compares a current test result with previous test results of the same person, and detects whether there is a substantial difference, as can be defined as a critical difference as per previous section, or defined by other pre-defined criteria. If the difference exceeds the pre-defined criteria, the result is reported only after manual confirmation by laboratory personnel, in order to exclude a laboratory error as a cause of the difference.^[4] In order to flag samples as deviating from previously, the exact cutoff values are chosen to give a balance betweensensitivity and the risk of being overwhelmed by false-positive flags.^[5] This balance, in turn, depends on the different kinds of clinical situations where the cutoffs are used, and hence, different cutoffs are often used at different departments even in the same hospital.^[5]

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The development of new techniques for monitoring is an advanced and developing field insmart medicine, biomedical-aidedintegrative medicine,alternative medicine,self-tailoredpreventive medicine andpredictive medicine that emphasizes monitoring of comprehensive medical data of patients, people at risk and healthy people using advanced, smart, minimallyinvasivebiomedical devices,biosensors,lab-on-a-chip (in the futurenanomedicine^[6][7] devices likenanorobots) and advancedcomputerizedmedical diagnosis and early warning tools over a short clinical interview anddrug prescription.

Asbiomedical research,nanotechnology andnutrigenomics advances, realizing the human body'sself-healing capabilities and the growing awareness of the limitations ofmedical intervention by chemicaldrugs-only approach of old school medical treatment, new researches that shows the enormous damage medications can cause,^[8][9] researchers are working to fulfill the need for a comprehensive further study and personal continuousclinical monitoring of health conditions while keeping legacy medical intervention as a last resort.

In many medical problems, drugs offer temporary relief of symptoms while theroot of a medical problem remains unknown without enough data of all ourbiological systems^[10]. Our body is equipped with sub-systems for the purpose of maintaining balance and self healing functions. Intervention without sufficient data might damage those healing sub systems.^[10] Monitoring medicine fills the gap to prevent diagnosis errors and can assist in future medical research by analyzing alldata of many patients.

The development cycle in medicine is extremely long, up to 20 years, because of the need for U.S.Food and Drug Administration (FDA) approvals, therefore many of monitoring medicine solutions are not available today in conventional medicine.

Blood glucose monitoring

In vivoblood glucose monitoring devices can transmit data to a computer that can assist with daily life suggestions forlifestyle ornutrition and with thephysician can make suggestions for further study in people who are at risk and help preventdiabetes mellitus type 2 .^[11]

Stress monitoring

Bio sensors may provide warnings when stress levels signs are rising before human can notice it and provide alerts and suggestions.^[12] Deep neural network models using photoplethysmography imaging (PPGI) data from mobile cameras can assess stress levels with a high degree of accuracy (86%).^[13]

Serotonin biosensor

Futureserotonin biosensors may assist withmood disorders anddepression.^[14]

Continuous blood test based nutrition

In the field ofevidence-based nutrition, alab-on-a-chipimplant that can run 24/7blood tests may provide a continuous results and a computer can provide nutrition suggestions or alerts.

Psychiatrist-on-a-chip

In clinical brain sciencesdrug delivery and in vivoBio-MEMS basedbiosensors may assist with preventing and early treatment of mental disorders

Epilepsy monitoring

Inepilepsy, next generations oflong-term video-EEG monitoring may predictepileptic seizure and prevent them with changes of daily life activity likesleep,stress,nutrition andmood management.^[15]

Toxicity monitoring

Smart biosensors may detect toxic materials suchmercury andlead and provide alerts.^[16]

• Medical equipment
• Medical test
• MECIF Protocol
• Nanoelectromechanical system (NEMS)
• Functional medicine
• Wireless ambulatory ECG

• Monitoring Level of Consciousness During Anesthesia & Sedation, Scott D. Kelley, M.D.,ISBN 978-0-9740696-0-9
• Healthcare Sensor Networks: Challenges Toward Practical Implementation, Daniel Tze Huei Lai (Editor), Marimuthu Palaniswami (Editor), Rezaul Begg (Editor),ISBN 978-1-4398-2181-7
• Blood Pressure Monitoring in Cardiovascular Medicine and Therapeutics (Contemporary Cardiology), William B. White,ISBN 978-0-89603-840-0
• Physiological Monitoring and Instrument Diagnosis in Perinatal and Neonatal Medicine, Yves W. Brans, William W. Hay Jr,ISBN 978-0-521-41951-2
• Medical Nanotechnology and Nanomedicine (Perspectives in Nanotechnology), Harry F. Tibbals,ISBN 978-1-4398-0874-0

• Media related toMedical monitoring at Wikimedia Commons

• Medical monitoring
• Nanomedicine
• Intensive care medicine
• Anesthesia

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