Measurement techniques of non-invasive blood pressure in animals

30/06/2022

Blood pressure is the reference point for the homeostatic regulation of the cardiovascular system. Non-invasive blood pressure is characterized by simplicity, cheapness, and safer and hygienic use, but the accuracy is lower than that of invasive invasive measurements, and the unit is expressed in mmHg.
(1) Systolic blood pressure: (SBP)
(2) Diastolic blood pressure: (DBP)
(3) Mean arterial pressure: (MAP)





Introduction to the principle of non-invasive blood pressure measurement
Concussion method
Measurement principle: The cuff is inflated to a certain pressure to completely block the arterial blood flow. As the pressure decreases, the arterial blood flow will be completely blocked - gradually opened - completely open, and the pulsation of the arterial blood vessel wall will be in the cuff. Shock waves are generated in the gas. SBP (systolic blood pressure), MBP (mean pressure) and DBP (diastolic blood pressure) can be obtained by measuring and analyzing the pressure vibration waves in the cuff during deflation.

 Produces the first clearest signal - reflecting SBP
 When the oscillation amplitude reaches its peak - reflecting the MAP
 When the pressure in the cuff suddenly decreases - reflecting DBP





clinical significance
Normal blood pressure is the premise of blood circulation, and blood pressure is kept normal under the regulation of various factors, so as to provide sufficient blood volume to various tissues and organs to maintain normal metabolism.
Blood pressure that is too low or too high (hypotension, high blood pressure) can have serious consequences.
Since hypotension is common in animals following surgery, animals should have their blood pressure measured at least once after all surgical activities have been completed.



NIBP procedure for animals:
1) Before measurement, the animal type must be confirmed.
2) Choose a suitable cuff, and tie the cuff to confirm that the cuff has been completely deflated, and then tie it to the upper arm or thigh of the animal. Make sure that the middle part of the balloon just presses the brachial artery, femoral artery, and anterior tibial artery, and make sure that the sleeve is not too tight around the limb, otherwise it may cause limb discoloration or even ischemia
3) Press the NIBP start key to start the measurement

 



Practical tips for blood pressure measurement:
*The width of the cuff should be approximately 40% of the circumference of the measurement point of the limb to be measured;
*A cuff that is too small will result in false high readings, and a cuff that is too large will result in false low readings;
*For all non-invasive blood pressure measurement technologies, only when the blood pressure value measured repeatedly is abnormal, corresponding treatment methods can be used to adjust blood pressure;
* For sick but stable animals, blood pressure should be measured every 4-6 hours;
*In critically ill patients, blood pressure should be measured more frequently, or blood pressure changes should be measured continuously through the arterial catheter.



common problem
1, blood pressure can not be measured
* Determine if the measurement type is selected correctly
*Whether the cuff and airway are connected, whether there is air leakage or blockage,
*Whether the sleeves are tied and the size of the sleeves is suitable
*Whether the cuff inflates and deflates normally after starting the measurement (observe the cuff pressure)
*Whether the animal is special
*Whether the animal has a special constitution
2. Unable to cheer
 *Internal circuit problem
3. Inaccurate blood pressure measurement
 * Confirm that there is no external interference, such as exercise, abnormal mood, etc.