1. The monitor is a device or system to measure and control the patient's physiological parameters, and can be compared with the known set values, if there is an exceeding of the standard
can be issued an alarm.
2. The monitor is different from the monitoring and diagnostic equipment, it must be 24 hours continuous monitoring of the patient's physiological parameters, detect the trend of change,
pointing out the critical situation for the doctor's emergency treatment and the basis for treatment, so that complications to minimize to alleviate and eliminate
the purpose of the disease.
The purpose of the monitor is not only to measure and monitor physiological parameters, but also to monitor and handle the conditions before and after medication and surgery.
3. Monitor optional parameters: cardiac, respiratory, blood pressure (non-invasive and invasive two kinds), oxygen saturation, pulse rate, body temperature, end of respiratory carbon dioxide, respiratory mechanics, anesthesia gases, cardiac output (invasive and non-invasive), EEG dual-frequency index, etc.
Two. Scope of clinical application of the monitor
In surgery, post-surgery, trauma care, coronary heart disease, critically ill patients, neonates, preterm infants, hyperbaric oxygen chambers, labor and delivery
rooms and so on.
III. Monitor classification
1. According to the structure is divided into four categories: portable monitors, plug-in monitors, telemetry monitors, HOLTER (24-hour ambulatory electrocardiogram) cardiac monitors.
2. According to the function is divided into three categories: bedside monitor, central monitor, leaving the hospital monitor (telemetry monitor).
Bedside monitor is set up in the bedside with the patient connected to the instrument, the patient's various physiological parameters or some state of continuous monitoring, to be displayed on the alarm or record, it can also be with the central monitor to form a whole to work.
Central monitor, also known as the central system monitor, which is composed of the main monitor and a number of bedside monitors, through the main monitor can control the work of the bedside monitors, the situation of a number of monitored objects at the same time for monitoring, one of the important task is to complete the abnormal physiological parameters and the automatic recording of medical records.
Leaving the hospital monitor (telemetry monitor) so that the patient can carry a small electronic monitor, can be in and out of the hospital on the patient's some kind of physiological parameters for continuous monitoring, for doctors to carry out non-real-time examination.
Four. Measurement of physiological parameters of monitoring
1. ECG is one of the most basic monitoring instrument monitoring project, ECG signal is obtained through the electrode, monitoring electrodes
is a disposable AS-AGCI button electrode.
2. Heart rate is the number of heart beats per minute. Heart rate measurement is based on the electrocardiogram waveform, which determines the instantaneous heart rate and the average heart rate.
Healthy adults in the quiet state average heart rate is not 75 beats / min, the normal range of 60-100 beats / min. Under
different physiologic conditions, the heart rate can be as low as 40-50 beats/min and as high as 200 beats/min.
Monitor heart rate alarm range: the low limit of 20-100 beats / min, the high limit is 80-240 beats / min.
3. Breathing refers to the monitoring of the patient's respiratory rate, that is, respiratory rate. Respiratory rate is the number of times the patient breathes in a unit of time
in minutes.
When breathing calmly, it is 60-70 breaths/minute for newborns and 12-18 breaths/minute for adults.
There are two types of measurements for respiratory monitoring: thermal and impedance
Thermal respiratory measurements are made with a thermistor placed at the nostrils. When airflow passes over the thermistor, it is subjected to heat exchange from the flowing airflow and the resistance value is changed, thus the respiratory rate is measured.
Impedance type respiratory measurement is based on the human respiratory movement, the chest and arm muscles alternately flaccid, the thorax is also alternately deformed, the electrical impedance of the muscle tissue is also alternately changed, the respiratory impedance (pulmonary impedance) and the lung capacity of the existence of a certain relationship between the lung impedance with the increase in lung capacity and increase. Impedance respiratory measurement is designed according to the change of pulmonary impedance.
The respiratory impedance electrode is used in conjunction with the ECG electrode in monitoring measurements, i.e., the ECG electrode is used to detect both the ECG signal and the respiratory impedance.
4. Invasive blood pressure is the monitoring of the patient's central venous pressure, left atrial pressure, cardiac output and cardiac floatation catheter.
Central venous pressure is the large thoracic venous pressure or right atrial, which is more reflective of overall venous return than localized venous pressure, which is 6.7-10.7 KPA in normal subjects and up to 22.7 KPA in patients with cardiac 3 failure.
Central venous pressure is measured by inserting an intravenous catheter from the jugular vein and femoral vein, and entering the junction of the superior and inferior vena cava and the right atrium through the large vein.
Left atrial pressure can indicate the ability of the left ventricle to fill and discharge, left heart failure, the left look forward to the ventricle's blood discharge is reduced, the left atrial pressure is elevated, can cause pulmonary stasis and emphysema,,, but the cardiac discharge is also increased. Therefore, monitoring and maintaining an appropriate left atrial pressure is extremely important for maintaining cardiac output.
Left atrial pressure is measured by inserting a cardiac catheter into the pulmonary artery and determining the pulmonary artery pressure to indirectly determine the left atrial pressure, or by inserting a cardiac catheter directly into the left atrium through the left upper pulmonary vein and left atrial junction.
5. Non-invasive blood pressure monitoring uses the Koch sound detection method, using an inflatable cuff to block the circumflex artery, in the process of the pressure drop at the end of the block
a series of sounds of different pitches will appear, according to the pitch and time can be judged by systolic and diastolic blood pressure, that is, the Koch
sound.
When monitoring, a microphone is used as the sensor, and when the cuff pressure is higher than the systolic pressure, the blood vessels are flattened, the blood
fluid under the cuff stops flowing, and the microphone has no signal. When the microphone measures the first kurtosis, the pressure corresponding to the cuff is systolic.
The microphone then measures the kurtosis again from the decrescendo phase to the silent phase, and the pressure corresponding to the cuff is diastolic.
6. Cardiac output is an important measure of cardiac function, which is reduced in certain pathologic conditions, leaving the myocardium with an inadequate supply of nutrients
. Cardiac output is the amount of blood ejected from the heart per minute, and it is measured by injecting a certain amount of
knowledge agent into the bloodstream in a certain way, and after diffusion in the bloodstream, the change in the indicator is measured to calculate the cardiac output.
There are two methods of cardiac output measurement: the FICK method and the thermodilution method
The FICK method uses oxygen as an indicator in the open circulation, and since the amount of oxygen exchanged between the pulmonary capillaries and alveoli
is directly proportional to the pulmonary blood flow, it is possible to measure cardiac output by measuring the concentration of the itch in the pulmonary arteries and pulmonary veins.
The thermodilution method uses cold saline as the indicator and a Swan-Ganz floating catheter with a thermistor as
a cardiac catheter. The thermistor is placed in the pulmonary artery and cold saline is injected into the right atrium to calculate cardiac output.
7. Body temperature reflects the results of the body's metabolism and is one of the conditions for normal functional activity.
The temperature inside the body is called "body core temperature", reflecting the condition of the head or trunk, generally measured from the mouth, axilla, rectum, the Chinese statistics
Meter shows that the oral temperature 36.7-37.7 degrees, axillary temperature 36.9-37.4 degrees, rectal temperature 36.9-37.4 degrees, and the temperature of the rectum 36.9-37.4 degrees. 37.4 degrees, rectal temperature 36.9-37.9 degrees.
8. Pulse is the phenomenon of the periodic pulsation of arterial blood vessels in response to the contraction and expansion of the heart. Pulse consists of changes in a number of physical quantities, such as intravascular pressure, volume, displacement, and
wall tension.
Optoelectronic volumetric pulse measurements are the most common of the monitoring measurements, and the sensor consists of a light source and an optoelectronic transducer
which is clamped to the patient's fingertip or auricle. Light source selection of arterial blood in the oxygenated hemoglobin selectivity of a certain wavelength
long, preferably with light-emitting diodes, whose spectrum in the 6 * 10-7 * 10 M. This beam of light through the peripheral vasculature of the human body, when the volume of arterial
vein congestion changes, change the transmittance of this beam of light by the optoelectronic converter receives by the tissue transmittance or reflection of
light, converted into an electrical signal, the light is transmitted to the patient's finger or ear.
Light is transformed into an electrical signal and sent to an amplifier for amplification and output, thus reflecting the change in arterial vasculature volume.
Pulse is a signal that changes periodically with the heart's beat, and the volume of the arterial vasculature also changes periodically, and the cycle of the signal change of the photoelectric converter
is the pulse rate.
9. Blood gas monitoring focuses on partial pressure of oxygen (Po2), partial pressure of carbon dioxide (Pco2), and oxygen saturation (Spo2).
Oxygen and carbon dioxide exist in the blood in both physically dissolved and chemically bound states, and it is the chemical binding that makes the blood much more capable of transporting O2 and Co2.
Po2 is a measure of the oxygen content of the arterial blood vessels.
Pco2 is a measure of the amount of carbon dioxide in the venous vasculature.
In O2 transportation, O2 mainly exists with hemoglobin in the form of binding in the red blood cells, the amount of dissolved is very small, so per 100 ml of blood, the maximum amount of hemoglobin binding oxygen is called Oxygen Content (OCP), the amount of oxygen that hemoglobin actually binds is called Oxygen Content (OCN).
Blood oxygen saturation is the ratio of oxygen content to oxygen capacity.
Monitoring of oxygen saturation is also measured by photoelectric method, with the same sensor as for pulse measurement. Blood is bright red when Po2 is high and dark red when Po2 is low. The photoelectric converter has a low-pass characteristic. When light passes through blood with different Po2, the photoelectric converter accepts different frequencies of light, and due to the low-pass characteristic of the photoelectric converter, different frequencies of light pass through the photoelectric converter with different sensitivities. By measuring the sensitivity of the photoelectric converter, Po2 can be determined, and then Spo2 can be determined according to the oxygen separation curve.