ĐO HA ĐỘNG MẠCH XÂM LẤN

ĐO HA ĐỘNG MẠCH XÂM LẤN Chỉ định Chia thành nhóm chính: Khơng đo huyết áp động mạch khơng xâm lấn Cần theo dõi huyết áp động mạch liên tục: Bệnh lý cần theo dõi huyết động liên tục Phẫu thuật hay thủ thuật tim, mạch Lấy máu xét nghiệm liên tục (khí máu) NIHON KOHDEN SPACELABS  Nối module vào máy Nihon Kohden vò trí Press1  Nối module vào máy Spacelabs T1-2 ◦ Pha heparin 1000Ul (0,2ml heparin) vào dung dòch NaCl 0,9% 500ml ◦ Khóa dây dòch truyền, cắm bầu chứa vào chai Nacl ◦ Xả dòch vào khỏang 1/3bầu ◦ Mở khóa xả đuổi khí hệ thống day, sau khóa lại ◦ Đặt chai dòch vào túi áp lực treo lên giá ◦ Nối dây vào dây nối tranducer ◦ Mở chia ◦ Bóp nhẹ khóa màu xanh để làm dòch chảy qua tranducer ◦ Tiếp tục bóp nút xanh dòch chảy vào hệ thống day nối dài để đuổi khí ◦ Bơm túi tạo áp lực lên mức 300 mmHg, với áp lực trên, tốc độ dòch 2-4 ml/giờ, ◦ Pha 50 ml NS + 0,02 ml heparin ◦ Gắn vào đầu tranducer ◦ Tăng tốc độ bơm để đuổi khí hệ thống dây ◦ Tốc độ trì 2ml/giờ ◦ Nối dây đo áp lực vào nắp chụp cho that khít ◦ Kiểm tra lại tất mối nối  The dicrotic notch recorded directly from the central aorta is termed the incisura (from the Latin, “a cutting into”) The incisura is sharply defined and is undoubtedly related to closure of the aortic valve.[61]  In contrast, the peripheral arterial waveform generally displays a later, smoother dicrotic notch that only approximates the timing of aortic valve closure and depends more on properties of the arterial wall  Note that the systolic upstroke of the radial artery pressure trace does not appear for 120 to 180 msec after inscription of the ECG R wave (see Fig 40-11 ) This interval reflects the sum of times required for spread of electrical depolarization through the ventricular myocardium, isovolumic left ventricular contraction, opening of the aortic valve, left ventricular ejection, transmission of the aortic pressure wave to the radial artery, and finally, transmission of the pressure signal from the arterial catheter to the  If the monitoring system has a natural frequency that is too low, frequencies in the monitored pressure waveform will overlap the natural frequency of the measurement system As a result, the system will resonate and pressure waveforms recorded on the monitor will be exaggerated or amplified versions of true intra-arterial pressure ( Fig 40-4 ) This phenomenon is the familiar arterial pressure waveform that displays overshoot, ringing, or resonance In these instances, the recorded systolic blood pressure overestimates true intra-arterial pressure  Most catheter-transducer systems are underdamped but have an acceptable natural frequency that exceeds 12 Hz If the system's natural frequency is lower than 7.5 Hz, the pressure waveform is often distorted, and no amount of damping adjustment can restore the monitored waveform to adequately resemble the original waveform.[47] If, on the other hand, the natural frequency can be increased sufficiently (e.g., 24 Hz), damping will have minimal effect on the monitored waveform, and faithful reproduction of intravascular pressure is achieved more easily (Figs 40-6 and 40-7 [0060] [0070]) In other words, the lower the natural frequency of the monitoring system, the more narrow the range of damping coefficients that can be tolerated to ensure faithful reproduction of the pressure wave For example, if the monitoring system's natural frequency is 10 Hz, the damping coefficient must be between 0.45 and 0.6 for accurate monitoring of the  From these considerations it follows that a pressure monitoring system will have optimal dynamic response if its natural frequency is as high as possible.[51] In theory, this is best achieved by using short lengths of stiff pressure tubing and limiting the number of stopcocks and other monitoring system appliances Blood clots and air bubbles trapped and concealed in stopcocks and other connection points will have similar adverse influences on the system's dynamic response As a general rule, adding air bubbles to monitoring systems will not improve their dynamic response because any increase in system damping is always accompanied by a decrease in natural frequency  To assess the amount of distortion existing in a pressure monitoring system, the fast-flush test provides a convenient bedside method for determining the system's dynamic response [47] [49] [51] To perform this test, the fast-flush valve is opened briefly, and the resulting flush artifact is examined Natural frequency is inversely proportional to the time between  when blood pressure is lower in one arm than in the other or when the pulses are weaker on one side, one should never insert an arterial catheter on the side with the weaker pulse because determination of blood pressure from this site will probably underestimate true aortic pressure In addition to atherosclerosis, other pathologic conditions such as arterial dissection or embolism preclude accurate monitoring of pressure from the affected sites ... thành nhóm chính: Khơng đo huyết áp động mạch khơng xâm lấn Cần theo dõi huyết áp động mạch liên tục: Bệnh lý cần theo dõi huyết động liên tục Phẫu thuật hay thủ thuật tim, mạch Lấy máu xét nghiệm... Khóa chia lại •  Máy sẵn sàng đo áp lực động mạch ◦ Điều chỉnh giới hạn báo động  Nhấn menu  press  press p1 alarm  Nhấn sys, dia hay mean  nhấn vào mức hay để điều chỉnh  Nhấn nut ... dòch 2-4 ml/giờ, ◦ Pha 50 ml NS + 0,02 ml heparin ◦ Gắn vào đầu tranducer ◦ Tăng tốc độ bơm để đuổi khí hệ thống dây ◦ Tốc độ trì 2ml/giờ ◦ Nối dây đo áp lực vào nắp chụp cho that khít ◦ Kiểm tra