Equipment for artificial life support and monitoring of human vital functions
Circadian blood pressure monitoring
Traditionally made when examining patients single measurement of blood pressure (BP) do not always reflect the true value of it, do not give an idea of the daily trend. This approach is not possible diagnosis of hypertension, the selection of antihypertensive agents, assess their effectiveness (especially after a single application) and the ratio of treatment.
In a fairly significant number of patients with a visit to the doctor, a frequently in clinical practice, with single measurements revealed high numbers of blood pressure, sometimes by 20-40 mmHg higher than when measured at home. Sometimes it is mistakenly interpreted as a hypertension, but more frequently - as "white coat effect". Outpatient ambulatory blood pressure monitoring (DMAT) in a normal human life helps to eliminate this effect, improve the quality of diagnosis and define the need and treatment strategy.
Additionally, DMAT helps identify false-negative cases when the disposable blood pressure measurements obtained normal values and are considered as normotensive patients , although in reality are hypertensive , ie at -monitoring them throughout the day are more high numbers of pressure.
In current approaches to the treatment of hypertension (GB) should be selected drugs that are capable of maintaining an adequate level of blood pressure for 24 hours. Thus the importance of DMAT as a method of assessing the quality of antihypertensive therapy can not be overemphasized .
Blood pressure monitoring during the day and more can be used not only for diagnosis and monitoring the effectiveness of treatment of arterial hypertension (AH), but also to study the effect on the blood pressure of various stress, diet, alcohol intake, smoking, physical activity, concomitant drug therapy, etc. etc.
DMAT - the only non-invasive method of examination, which allows:
- Obtain information on the rate and blood pressure fluctuations during the day, during wakefulness and sleep;
- Identify patients with nocturnal hypertension, which increased the risk of organ damage;
- Assess the adequacy of BP reduction between doses of regular doses of the drug;
- Control the absence of excessive blood pressure lowering at peak drug action or lack of decline before the next intake, especially for zastosuvanniprolonhovanyh antihypertensive drugs targeted at single dose per day;
- Identify patients with low or high BP variability (insufficient or excessive decrease it at night) and decide on the recruitment of anti-hypertensive drug, taking into account its effect on blood pressure values not only in the daytime, but at night.
Types of monitors pressure
To achieve the objectives of the doctor and the correct evaluation of DMAT necessary knowledge of the principles and operation of devices used for pressure-monitoring.
The work of all ambulatory pressure meters based on the identification of restoration of blood flow through the artery after perezhymu and subsequent discharge pressure cuff. As used in some monitors principle of measuring the pressure in the injection of air into the cuff gives inflated results as to overcome the elastic artery wall by clamping it necessary to create excess pressure that exceeds the pressure in the vessel, particularly for its hardening.
To determine the restoration of blood flow through the vessel may apply different methods: volumetric or elektropletizmohrafiya, fotopletizmohrafiya (sensors operating in passing or reflected light and react to the appearance of oxyhemoglobin), ultrasonic blood flow detector capacitance transducers pulse sensors that record the clearance of isotopes etc.
Not all of these techniques are applicable in the design nosym devices for blood pressure monitoring. Impedance of the system, for example, where the restoration of blood flow through the arteries is controlled by reohrafichnym not been used in ambulatory practice not only because of the complexity of the operation, but not because of the small dimensions of the devices.
Ultrasonic sensors are based on the Doppler effect, also were used in systems of ambulatory blood pressure monitoring via low robustness and complexity of the positioning sensor on artery blood flow.
The first serial ambulatory pressure monitors used acoustic measurement method is based on the detection of Korotkoff tones with special microphones embedded in the cuff. Overlay Cuff require precise placement of the microphone artery and maintaining its position in all dimensions, it is difficult to provide during the day.
This method, although it became the largest distribution and is considered the benchmark does not always satisfy the users due to lack of precision measuring diastolic pressure (ADT) where errors can reach 10-20%. Also, still not fully elucidated the mechanism of the origin of Korotkoff tones and the dependence of their amplitude and frequency characteristics, as well as the onset and disappearance of the elastic properties of the arteries.
Monitors, built on the principle of acoustic measurements are not adequately protected from external noise and interference, resulting in friction sleeve located in her microphone against clothing, etc. So were produced combined with simultaneous recording of the ECG, which provided immunity that attaches to the microprocessor pressure values only colors that coincide with the R wave electrocardiosignal and the remaining acoustic phenomena are regarded as artifacts.
Disadvantages pressure monitor with acoustic measurement principle not limited. Built-in cuff sensors are sensitive to mechanical damage, often fail because of the broken crystal piezoceramic or wire failure.
More suitable for use in ambulatory monitor system was recognized oscillometric method. Oscillatory systems, such as monitor AVRM -02 by " Meditech " (Hungary) , were quite widespread , as they practically insensitive to noise , can quickly and easily apply the cuff , without worrying about the accuracy of positioning. An important advantage of oscillator method is to determine the average pressure ( ATsr ) , details of which are necessary for the understanding of the course of development of different forms hipertoniy , depending on the definition of blood pressure from external factors and therapeutic interventions . These monitors are suitable for monitoring blood pressure in patients with weak pulse, deaf Korotkov tones or low blood pressure.
In devices based on the oscillator method , there systolic dimension (ATC ) and average ( ATsr ) blood pressure. For PBX accepted value of pressure in the cuff at the time the first pulsations during decompression , and in ATsr - pressure corresponding to the appearance of oscillations of maximum amplitude [6 ]. Diastolic pressure ( ADT ) based on an automatic analysis of the amplitude and shape pulsations of air in the cuff on algorithms that are usually kept secret Firms developers.
Monitors other designs ATsr often calculated automatically by adding 1 /3 of the pulse pressure to the diastolic .
Recently, there have monitors with pulse-dynamic way of determining blood pressure. For example, the monitors' Dinapuls "American company" PulseMetric ", instead of using the amplitude of the so-called" similar "or outline a way to assess where in the analysis of each oscillation of air in the cuff is made construction, a patented method of pulse wave in the arteries and it is measured by ATS and ADT, and ATsr automatically calculated by adding up to 1/3 systolic 2/3 diastolic.
Displays on the computer screen reconstructed for each individual reduction pulse wave analysis allows the detection of irregular shape (arytmychni) reduction, which helps in assessing accuracy.
By themselves, the value of ATS and ADT defined by any indirect method is not numeric pressure inside the artery. It's more pressure, you want to create a cuff to stop blood flow and pulse wave propagation along the artery or the changing nature plays with her colors. These values are pressure though with true respect in direct proportion , yet are much higher and are purely local and conditional value at the place of the imposition of the cuff , the patient and the type of equipment used . However, ignore these figures should not be, because they may be relevant to the characteristics of the vascular system and blood circulation in general. At the same time , the value ATsr absolute and not dependent on the arterial wall , soft tissue and covered limbs and properties cuff .
Ostsyllometrychni blood pressure monitoring system is also not without drawbacks. If their application is mandatory security at the time of measurement estate limbs, which cuff. Therefore, some firms, including firm "Schiller" (Switzerland), producing oscillating pressure monitors in which to improve noise immunity uses a combination of acoustic and oscillometric methods.
Apparently, the development of blood pressure monitors appropriate to use a combination ostsyllyatornoho and electrocardiography or, in extreme cases, acoustic and electrocardiography, but best of all three methods, as is done in combination monitors " Kardiotehnika -4000 -AD " company " INKART " (St. Petersburg ), for monitoring blood pressure and ECG. It should be noted that the use of monitors, blood pressure, ECG which only serves to control the accuracy of the allocation ripple or ringing Korotkov , cost is not entirely justified, because it requires the purchase of one-time ECG electrodes , which increases the cost of the study. But, due to greater noise immunity, blood pressure through them can be carried out during exercise .
In modern ambulatory blood pressure monitor pumping air into the cuff is automatic to a certain, predetermined value. If this value is significantly higher than the systolic blood pressure or does not reach it, then repeated measurements automatically adjusts the pressure generated in the cuff.
The measurements are usually performed for a given program during decompression that occurs on different algorithms. Some monitors rate of discharge pressure in the cuff is uneven - first pressure dropped slowly, and after determining PBX - faster, in other uniform rate - 2-3 mmHg pulse to punch in the third it is automatically adjusted depending on the pressure and heart rate , which is better because of the constant uniform tightening procedure drop blood pressure , especially in the rare pulse and cause discomfort to the patient. Increasing the speed of decompression can lead to errors in the measurements , more noticeable when bradycardia.
Accuracy pressure monitors are not usually controlled by the user , as guaranteed by the manufacturers of compliance with international requirements and standards. Patient safety is ensured by monitors software or mechanical means to automatically turn off the power of the compressor and dump the cuff pressure in excess of the maximum value of pressure or time compression limbs controlled by built-in real time clock. In addition, the monitors can be equipped with the manual emergency shutdown of the compressor and pressure relief .
Daily monitoring CARDIAC ACTIVITY
Holter-monitoring - a method to evaluate the patient's cardiac function in terms of the traditional way of life.
As a result of physician cardiologist can watch the reaction of the heart to physical and emotional stress, to determine possible myocardial ischemia as heart during sleep and during the day. Also, the method allows to determine the cause of syncope and presyncope. Research conducted in the outpatient mode, so the patient is free to go about their everyday business. This technique is highly informative and completely safe for the patient.
Circadian blood pressure monitoring and cardiac activity
Monitor blood pressure and electrocardiosignal designed for simultaneous monitoring changes in blood pressure and heart.
The main components of the monitor are:
?span style='font:7.0pt "Times New Roman"'> electronic unit,
?span style='font:7.0pt "Times New Roman"'> compression Cuff AT the shoulders
?span style='font:7.0pt "Times New Roman"'> Cable EX.
Daily monitoring of blood oxygen saturation
Pulse Oximeter - Medical diagnostic device for measuring the oxygen saturation in capillary blood. There are many pathologies involving hypoxia (lack of oxygen in the blood). In such cases, the need to constantly monitor the saturation.
In pulse oximeter has two LEDs that emit red and infrared light, and photodetector (photodetector) that it takes light. The changes in the ratio of absorption of red and infrared light receiver during systole and diastole, pulse oximeter determines the content of oxygenated hemoglobin in arterial blood, as infrared light absorbs oxygenated hemoglobin and red light - deoksyhenovannyy hemoglobin.
Saturation, pulse oximeter designate certain characters - SpO2. If saturation measured by laboratory (invasive) by (so-called true saturation), it denoted symbols - SaO2. Normal values of saturation (SpO2) - 95-98%.
Whatever the correct figure numbers saturation can be compared with the partial pressure of oxygen in the blood (PaO2).
? Since saturation (SpO2) 95-98% answers - 80-100 mm Hg. century. (PaO2).
? carbonation (SpO2) of 90% corresponds to - 60 mmHg (PaO2).
? carbonation (SpO2) of 75% corresponds to - 40 mmHg (PaO2).
Monitoring equipment for obstetrics and gynecology
Incubators the newborns
Incubators the newborns especially designed to create conditions newborns with extremely low body weight ranging from 500 g. The incubator is able to automatically maintain a stable temperature inside the incubator to maintain the temperature at a given level of the child's body and automatically maintain the humidity level inside the incubator without infecting with the child, even if prolonged nursing. Incubator at work exclude all factors adverse effect on the child while nursing.
Infant incubators with air temperature control and humidity system provides automatic control of oxygen supply. The system has a feedback device, such as an oximeter. Oxygen regulator is designed as a solenoid valve, input is connected to a source of fresh oxygen, and out - of incubator.
Emergency care is a complex open-type incubators for newborns. Infrared lamp automatically maintains a stable body temperature regardless of the child's environment. This system keeps the most severe children, who often need to manipulate. The system has an effective infrared heater that measures the temperature of the child 40 times in 1 second with an accuracy of 0.01 deg C and heat capacity changes. The system allows its use even as an operating table for surgery in infants. For stabilize body temperature need only specify the desired body temperature and observe the current temperature and alarms.
Fetal (embryonic) CTG fetal monitor registration
Fetal monitor to record cardiac activity (heart rate), motor activity of the fetus and uterine activity during pregnancy with automatic analysis of antenatal CTG (cardiotocography), taking into account gestational age ranging from 24 weeks to the development of regular labor.
PRINCIPLES OF RECEIPT OF MONITORING
Ultrasound
Pulsed Doppler directed system works with sensors 1.5 and 2.0 MHz. The sensor is fully internally shielded to minimize high-frequency emissions and interference of ultrasound.
Uterine.
For the convenience of the patient and ensure the accuracy of measuring the strength of uterine contraction using lightweight, flat protective ring tokodynamometr Cmita such as straps and buckles, as well as for the ultrasonic sensor.
Aktohrama.
To register, fetal movements using low-frequency component of the Doppler ultrasound signal using ultrasound transducer 1.5 MHz. Graphic curve is low frequency Doppler signals (which reflect the speed of less than 4 cm / s).
Apparatus for artificial respiration BEAR CUB 750psv focused on the use of infants with birth weight ranging from 300-400 grams. It has 14 possible modes of ventilation, allowing the unit to adapt to any condition of the newborn with respiratory disorders with minimal consequences of artificial ventilation. The device is supplied fully automatic humidifier that maintains heating and humidifying respiratory gas to the desired physiological level. A special sensor measures the tidal volume connector directly to the patient, allowing exactly 0.1 mL of shahom maintain standards of ventilation. In addition, the device allows to adapt to the child's spontaneous breathing, while the machine takes your breath synchronized with the patient's breathing efforts.
BRIEF ORGANIZATION intensive care
Need help in the intensive care can occur in any environment. The life of the victim in this case will depend on whether the person who assisted method has resuscitation (external cardiac massage and artificial respiration). Of course, full resuscitation may hold only a medical professional.
Established that the human body continues to function even after the cessation of breathing and heart activity, although it stops the supply of oxygen to the cells as a precondition for the existence of a living organism. Different tissues respond differently to the lack of blood supply to them and oxygen, so their extinction occurs at different times. Therefore, restoration of blood circulation and breathing with the help of a set of measures called resuscitation may bring a patient with a terminal condition.
Terminal condition can be caused by various reasons: shock, myocardial infarction, large blood loss, airway obstruction or asphyxia, electrical, drowning, falling asleep underground, etc.
In a terminal state distinguish 3 phases or stages:
?span style='font:7.0pt "Times New Roman"'> preagony condition;
?span style='font:7.0pt "Times New Roman"'> agony;
?span style='font:7.0pt "Times New Roman"'> clinical death.
In the state of consciousness of the patient preahonalnomu still exists, but it confused, blood pressure drops to zero, the pulse accelerated sharply and becomes threadlike, shallow breathing, shortness, skin pale.
During the throes of blood pressure and heart rate are not defined, eye reflexes (corneal, pupil reaction to light) disappear, breathing character gets swallowed air.
Clinical death - short transitional stage between life and death, duration of 3-6 minutes. Breathing and heart function absent zenytsi extended, skin cold, no reflexes. During this short period is still possible to restore vital functions by means of resuscitation. In later periods, irrevocable changes in tissues and clinical death enters the biological or real.
After returning the body from a state of clinical death initially reduced cardiac performance, respiration, and later self only later, when gone dramatic changes in metabolism and acid-base status may recover brain function.
The period of recovery of brain function is the longest. Even after short-term hypoxia and clinical death (less than a minute) consciousness may be absent for a long time.
Organizing a special cabinet in the clinic, pharmacy, any medical point where you need to have reanimatolohichnyy set is very important.
Ambulance shall be equipped with all necessary for the resuscitation and even for operations such as tracheostomy, cannulation of veins, arteries and heart, direct cardiac massage and others
Modern ambulances are equipped with:
1. doctor chair with back and headrest;
2. two-position automatic safety belt;
3. ambulatory table without electric hydraulic principle of;
4. stretcher with a possible function of transporting a patient from the accident to the bed;
5. Professional Series Defibrillator with:
?span style='font:7.0pt "Times New Roman"'> biphasic pulse of rectangular shape with innovative technology stabilization amperage (CCD),
?span style='font:7.0pt "Times New Roman"'> High contrast LCD monitor,
?span style='font:7.0pt "Times New Roman"'> 3-channel ECG
?span style='font:7.0pt "Times New Roman"'> cardioversion mode (synchronization with ECG)
?span style='font:7.0pt "Times New Roman"'> automatic ECG analysis,
?span style='font:7.0pt "Times New Roman"'> defibrillation in manual and automatic modes
?span style='font:7.0pt "Times New Roman"'> integrated pulse oximeter
?span style='font:7.0pt "Times New Roman"'> transthoracic pacemaker
?span style='font:7.0pt "Times New Roman"'> multiple adult / child electrodes for defibrillation ("utyuzhkamy")
?span style='font:7.0pt "Times New Roman"'> built-in thermal printer,
?span style='font:7.0pt "Times New Roman"'> Automatic storage of data on the memory card (ECG, duration of resuscitation, defibrillation episodes, audio);
6. apparatus for maintaining vital functions of the patient for machines intensive care in an emergency;
7. apparatus for oxygen inhalation, oxygen cylinders;
8. artificial lung device;
9. mount for 2 infuzytsiynyh bottles;
10. ?/span>Power socket for connecting an incubator for babies;
11. Power equipment from AC (230V), board the car and mains power.
APPARATUS FOR PROVIDING ARTIFICIAL human life
Artificial respiration
Штучна вентиляція легені?- ШВ?- (контролирует? механическ? вентиляция - ЦМ? - мето? за допомого?якого відновлюються ?підтримуються порушена функція легень - вентиляція ?газообмі?
The essence of mechanical ventilation (respirator) is compulsory introduction of air into the lungs. It is used in cases of respiratory failure, and the presence of incorrect or almost imperceptible breath. Artificial ventilation is designed to solve problems that normally perform the respiratory muscles. This task includes ensuring oxygenation and ventilation (removal of carbon dioxide) lung patient. With a beating heart effective CPR quickly improves patient. Skin acquire natural color, there is a pulse, blood pressure begins to manifest.
In the late 80-ies of XX century for prolonged ventilation proposed a new method of respiratory support - non-invasive or auxiliary ventilation via nasal and facial masks (NSHVL).
Apparatus "artificial kidney"
Hemodialysis - a mechanical cleansing the blood of waste salts and fluids necessary for patients whose kidneys are healthy enough to do the job. Hemodialysis is the most common method for the treatment of severe renal insufficiency. This procedure will help the patient to lead an active life, despite the disruption of the kidney.
Hemodialysis is usually awarded when a kidney patient can perform only 10-15% of the work. Hemodialysis takes over part of the functions of the kidneys - it controls the blood pressure of the patient, and maintains the normal balance of electrolytes in the body fluids. It also helps maintain a healthy acid-alkaline balance.
Hemodialysis is carried out using the apparatus "artificial kidney", whose main task is to clean the blood from a variety of toxic substances, including metabolic products. The volume of blood in the limits of the body remains constant.
The method is based on the principle of diffusion and convection substances of low and medium molecular weight through a semipermeable membrane, which allows you to remove toxic substances from blood and metabolic products. The need for dialysis occurs in severe kidney disease, or if you receive a large amount of blood toxins. ?/span>
Apparatus "artificial kidney" consists of the following components: a device for giving blood, a device for preparing and submitting dializuyuchoho solution, monitor dialyzer. The most important role is played by dialyzer. It contains a semi-permeable membrane based on cellulose or synthetic polymers. The membrane has a surface area of 0.2 to 2 m ², width 8, 11, 15 or 30 mm, pore diameter from 0.5 to 5 nm. It divides the inner space of the dialyzer into two parts (for blood and solution), each of which has its own entrance and exit. Blood vessels taken from the patient enters the dialyzer and is located on one side of the membrane, on the other side there is a solution that is similar to electrolyte composition of the blood.
By diffusion in the direction of lower concentration through the membrane material is removed with a small molecular weight (electrolytes, urea, creatinine, uric acid, etc.). By ultrafiltration removes excess water and substances with high molecular weight (30,000). The treated blood is returned to the blood vessels of the patient.
Prosedure of hemodialysis
Before the procedure, an artificial kidney machine washed, sterilized, with attached canister concentrate salts dialyzer attached to the patient, the system is administered heparin to prevent clotting. To the patient device can join veno-venous or arteriovenous way. If necessary, reusable patient implanted external arteriovenous shunt. With screen monitor and regulate the chemical composition, pH, blood pressure in the office and more. Patient safety provide special devices that protect it from air embolism, excessive ultrafiltration bacterial contamination. Duration of hemodialysis 5 - 6 hours.
Defibrillator
Ventricular fibrillation - the most common cause of sudden cardiac arrest in adults. Initial resuscitation (cardiac massage and artificial respiration) in these patients can not translate fibrillation to normal rhythm. Only the timely (early) defibrillation is the only chance to restore hemodynamic effective heart rate and save a patient with cardiac arrest from certain death. Timely defibrillation - is defibrillation, which is carried out in the first 5 minutes after the onset of cardiac catastrophe. With each minute of delay the chances of survival drop by 10-15%. After 7-10 minutes after the occurrence of atrial fibrillation patients return to life is almost impossible.
When electrical defibrillation through the patient's body by two spaced electrodes on the chest passed a short (0,01 seconds) electrical discharge of high voltage (7000 V), causing momentary depolarization of the maximum number of cardiomyocytes, which allows arrest existing cardiac arrhythmias and gives possibility of driver restore normal heart rhythm course excitement.
Possible causes of inefficiency defibrillation:
− Erroneous imposition of electrodes;
− Grease the electrodes is absent or very low (high resistance of the skin);
− Electrodes sufficiently tightly to the chest;
− Very low energy defibrillation;
− Lack of myocardial oxygen saturation.
Power the unit on AC 220 V, 50 Hz power supply provided 220-18, and in the absence of the network - from the onboard battery, a charge which takes place on the network through the power supply 220 V, 18 V and battery charger. Transducer (10-20) B - 5, +15, -15 V generates the necessary voltage to the machine. The unit charge high voltage (VV) capacitor is fed directly from the power supply 220 V, 18 V and provides a controlled explosive charge controller capacitor. Controller using capacitor energy explosives, pulse shaper via BB latches submits bipolar electrodes pulse with defined parameters and amplitude of the first half-wave selected on the electrode - the dispenser. Display provides information on the power supply, the battery when powered by battery, the battery charging status and performance of the apparatus.
Description of the electrical circuit defibrillator. After turning on the defibrillator high voltage switch S charges the capacitor C (capacitance of a capacitor depends on the amount of electricity injected into the patient, and the duration of the pulse defibrillation). The charged capacitor is disconnected from the power source and through the inductor is connected to the defibrillator electrodes. Capacitor discharge occurs only after pressing the buttons S1 and S2, which are located at the electrodes so that the doctor can just push them in a position where it does not touch your hands or metal electrodes or the patient's body. Inductance L in terms of discharge rounds off the top of the pulse and increases the length of its front (it is believed that defibrillation is critical in the first half-wave, the effect of subsequent "negative" current until finally clarified).
Short pulses of high-used for defibrillation, is produced by the accumulation capacitor discharge.
Charging process obeys the formula:
.
The voltage of the charged capacitor is given by:
The energy defibrillation ?in the absence of losses in an electric circuit, electrodes, etc. can be determined from the expression:
Defibrillator discharge process obeys the formula:
.
During discharge only a small part of the energy affects the heart due to the presence of different levels of resistance (impedance) of the chest. The value of energy required during defibrillation (defibrillation threshold) increases with time after cardiac arrest. For resuscitation of adults used empirically chosen level of 200 joules for the first two categories and 360 J for the following. Discharges DC must be applied at the correct formulation of the electrodes and good contact with the skin. The polarity of the electrodes is not crucial, since in their correct positions "breast" and "tip" on the screen projected defibrillator correct orientation of the complex. Electrode that is applied to the breast, placed on top of the right half of the chest under the collarbone. Electrode affixed to the top of the heart is located slightly lateral point of the normal projection of the apical impulse, but not for breast cancer in women. If unsuccessful, may apply other provisions of the electrodes, for example, at the top and the back surface of the chest.
Over recent years, semi-and automatic defibrillators. In conjunction with the patient, such devices are able to self-assess heart rate and perform the required level.
Some also allow you to evaluate the resistance of the chest in order to select the required amperage discharge. The latest generation of defibrillators using two-and three-phase waveform energy for successful defibrillation at lower energy force.
Daily monitoring of blood pressure, cardiac activity and blood oxygen saturation
Blood pressure monitoring. Traditionally made when examining patients single measurement of blood pressure (BP) do not always reflect the true value of it, do not give an idea of the daily trend. This approach is not possible diagnosis of hypertension, the selection of antihypertensive agents, assess their effectiveness (especially after a single application) and the ratio of treatment.
In a fairly significant number of patients with a visit to the doctor, a frequently in clinical practice, with single measurements revealed high numbers of blood pressure, sometimes by 20-40 mmHg higher than when measured at home. Sometimes it is mistakenly interpreted as a hypertension, but more frequently - as "white coat effect". Outpatient ambulatory blood pressure monitoring (DMAT) in a normal human life helps to eliminate this effect, improve the quality of diagnosis and define the need and treatment strategy.
Additionally, DMAT helps identify false-negative cases when the disposable blood pressure measurements obtained normal values and are considered as normotensive patients , although in reality are hypertensive , ie at -monitoring them throughout the day are more high numbers of pressure.
In current approaches to the treatment of hypertension (GB) should be selected drugs that are capable of maintaining an adequate level of blood pressure for 24 hours. Thus the importance of DMAT as a method of assessing the quality of antihypertensive therapy can not be overemphasized .
Blood pressure monitoring during the day and more can be used not only for diagnosis and monitoring the effectiveness of treatment of arterial hypertension (AH), but also to study the effect on the blood pressure of various stress, diet, alcohol intake, smoking, physical activity, concomitant drug therapy, etc. etc.
DMAT - the only non-invasive method of examination, which allows:
- Obtain information on the rate and blood pressure fluctuations during the day, during wakefulness and sleep;
- Identify patients with nocturnal hypertension, which increased the risk of organ damage;
- Assess the adequacy of BP reduction between doses of regular doses of the drug;
- Control the absence of excessive blood pressure lowering at peak drug action or lack of decline before the next intake, especially for zastosuvanni prolonhovanyh antihypertensive drugs targeted at single dose per day;
Identify patients with low or high BP variability (insufficient or excessive decrease it at night) and decide on the recruitment of anti-hypertensive drug, taking into account its effect on blood pressure values not only in the daytime, but at night.
Types of monitors pressure
To achieve the objectives of the doctor and the correct evaluation of DMAT necessary knowledge of the principles and operation of devices used for pressure-monitoring.
The work of all ambulatory pressure meters based on the identification of restoration of blood flow through the artery after perezhymu and subsequent discharge pressure cuff. As used in some monitors principle of measuring the pressure in the injection of air into the cuff gives inflated results as to overcome the elastic artery wall by clamping it necessary to create excess pressure that exceeds the pressure in the vessel, particularly for its hardening.
To determine the restoration of blood flow through the vessel may apply different methods: volumetric or elektropletizmohrafiya, fotopletizmohrafiya (sensors operating in passing or reflected light and react to the appearance of oxyhemoglobin), ultrasonic blood flow detector capacitance transducers pulse sensors that record the clearance of isotopes etc.
Not all of these techniques are applicable in the design nosym devices for blood pressure monitoring. Impedance of the system, for example, where the restoration of blood flow through the arteries is controlled by reohrafichnym not been used in ambulatory practice not only because of the complexity of the operation, but not because of the small dimensions of the devices.
Ultrasonic sensors are based on the Doppler effect, also were used in systems of ambulatory blood pressure monitoring via low immunity and difficulties with blood flow sensor positioned over the artery.
The first serial ambulatory pressure monitors used acoustic measurement method is based on the detection of Korotkoff tones with special microphones embedded in the cuff. Overlay Cuff require precise placement of the microphone artery and maintaining its position in all dimensions, it is difficult to provide during the day.