What are the parameters of the patient monitor?

What are the parameters of the patient monitor?

The standard 6 parameters of the monitor are ECG, respiration, non-invasive blood pressure, oxygen saturation, pulse, and body temperature. In addition, optional parameters include: invasive blood pressure, end-tidal carbon dioxide, respiratory mechanics, anesthetic gas, cardiac output (invasive and non-invasive), EEG bispectral index and so on.

ECG

The electrocardiogram is one of the most basic monitoring items of the monitoring equipment. The ECG signal is obtained through electrodes, and the monitoring electrodes are disposable AS-AGCI button electrodes.

Heart Rate

Heart rate refers to the number of times the heart beats per minute. Heart rate measurement is to determine the instantaneous heart rate and average heart rate based on the ECG waveform.

A healthy adult has an average heart rate of 75 beats per minute at rest, and the normal range is 60-100 beats per minute. Under different physiological conditions, the heart rate can be as low as 40-50 beats/min, and as high as 200 beats/min.

The monitor heart rate alarm range: the low limit is 20-100 beats/min, and the high limit is 80-240 beats/min.

Respiration refers to the breathing rate of the monitored patient, that is, the breathing rate. The respiratory rate is the number of times the patient breathes in a unit of time, and the unit is minutes.

There are two measurement methods for respiratory monitoring: thermal and impedance

Thermal breathing measurement uses a thermistor placed in the nostril. When the airflow passes through the thermistor, the thermistor is subjected to heat exchange by the flowing airflow, and the resistance value changes, thereby measuring the frequency of breathing.

Impedance respiration measurement is based on the alternating relaxation of the thoracic and arm muscles, alternating deformation of the thoracic cage, and alternating changes in the electrical impedance of the body tissues. There is a certain relationship between respiratory impedance (lung impedance) and lung capacity. Lung impedance varies with lungs. The increase in capacity increases. Impedance respiration measurement is designed based on changes in lung impedance.

In monitoring measurement, the respiratory impedance electrode and the ECG electrode are used together, that is, the ECG electrode is used to detect the ECG signal and the respiratory impedance at the same time.

IBP

Invasive blood pressure refers to monitoring the patient's central venous pressure, left atrial pressure, cardiac output, and cardiac floating catheter.

The central venous pressure is measured by inserting an intravenous catheter from the jugular vein and femoral vein through the large vein into the junction of the superior and inferior vena cava and the right atrium to measure the central venous pressure.

Left atrial pressure can indicate the ability of left ventricle to fill and discharge. Left heart failure, left and right ventricular blood output decreases, and left atrial pressure increases, which can cause pulmonary congestion and emphysema, but heart output also increases. Therefore, monitoring and maintaining proper left atrial pressure is extremely important for maintaining cardiac output.

The left atrial pressure is measured by inserting a cardiac catheter into the pulmonary artery and measuring the pulmonary artery pressure to measure the left atrial pressure indirectly, or by inserting the cardiac catheter directly into the left atrium through the connection between the upper left pulmonary vein and the left atrium.

NIBP

Non-invasive blood pressure monitoring uses the Korotkoff sound detection method. The brachial artery is blocked with an inflatable cuff. A series of sounds of different tones will appear during the pressure drop at the blocked end. According to the tone and time, the systolic and diastolic blood pressure can be judged, which is Korotkoff sound.

Heart Rate output is an important indicator of heart function. Under certain pathological conditions, cardiac output decreases, which makes the body's nutritional supply insufficient. Cardiac output is the amount of blood ejected by the heart per minute. It is measured by injecting a certain amount of indicator into the blood through a certain method, and after diffusion in the blood, measuring the change of the indicator to calculate the cardiac output.

There are two methods for the determination of cardiac output: FICK method and thermal dilution method.

The FICK method uses oxygen as an indicator in the open blood circulation. Since the oxygen exchange between the pulmonary capillaries and the alveoli is proportional to the pulmonary blood flow, the cardiac output can be measured by measuring the oxygen concentration of the pulmonary artery and pulmonary vein.

The thermodilution method uses cold normal saline as an indicator, and a Swan-Ganz floating catheter with thermistor as a cardiac catheter. The thermistor is placed in the pulmonary artery and cold saline is injected into the right atrium to calculate the cardiac output.

Temperature

Body temperature reflects the result of the body's metabolism and is one of the conditions for the body to carry out normal functional activities. The temperature inside the body is called "core temperature", which reflects the condition of the head or torso. It is generally measured from the mouth, axilla, and rectum. Statistics for Chinese people show that the oral temperature is 36.7-37.7 degrees, the axillary temperature is 36.9-37.4 degrees, and the rectal temperature 36.9-37.9 degrees.

Pulse Rate

Pulse is a phenomenon in which arterial blood vessels pulsate periodically with the dilation and contraction of the heart. Pulse includes changes in various physical quantities such as intravascular pressure, volume, displacement, and vessel wall tension.

The pulse is a signal that changes periodically with the beating of the heart, and the arterial blood vessel volume also changes periodically. The signal change period of the photoelectric transducer is the pulse rate.

Blood gas monitoring mainly refers to partial pressure of oxygen (PO2), partial pressure of carbon dioxide (Pco2) and blood oxygen saturation (Spo2).

Oxygen and carbon dioxide exist in the blood in two states: physical dissolution and chemical combination. It is precisely because of the presence of chemical combination that the blood's ability to transport O2 and Co2 is greatly improved.

Po2 is a measure of the oxygen content in arteries. Pco2 is a measure of the amount of carbon dioxide in the veins.

Blood oxygen saturation is the ratio of oxygen content to oxygen capacity.

The monitoring of blood oxygen saturation is also measured by photoelectric method, and the sensor and pulse measurement are the same.