Yadav Kavita, Jaryal Ashok Kumar, Coshic Poonam, Chatterjee Kabita, Deepak K K
Department of Physiology, All India Institute of Medical Sciences, Room no. 2009, Teaching block, Second floor, Ansari Nagar, New Delhi, India.
Transfusion Medicine (Blood Bank), All India Institute of Medical Sciences, New Delhi, India.
High Blood Press Cardiovasc Prev. 2016 Mar;23(1):25-30. doi: 10.1007/s40292-016-0130-y. Epub 2016 Feb 16.
Blood volume is an important determinant of the efficacy of the negative feedback mechanisms that maintain blood pressure. However, its effect on time profile and magnitude of the responses remain unstudied.
To study the effect of mild hypovolemia on time profiles and magnitude of changes in blood pressure and heart rate in healthy subjects before and after blood donation.
Fifty six healthy volunteer donors who signed up for blood donation were recruited (age 35 ± 7 years; weight 75 ± 9 Kg). Baseline beat to beat blood pressure and Lead II ECG was recorded for 5 min followed by orthostatic challenge for 3 min before and after blood donation.
The donation of 450 ml of blood did not lead to any changes in the resting systolic, diastolic or mean blood pressure. However, there was a significant decrease in pulse pressure after blood donation along with an increase in the heart rate. During orthostatic challenge, after blood donation there was a greater fall in systolic, diastolic, mean and pulse pressure along with a greater increase in heart rate as compared to before the blood donation. The latency to response and the total time to recovery of blood pressure and heart rate increased significantly after blood donation.
Maintenance of blood pressure after orthostatic challenge is not compromised after mild hypovolemia produced by donation of 450 ml of blood. However, mild hypovolemia results in increase in latency of response and is accompanied with larger magnitude of fall in blood pressure during orthostatic challenge.
血容量是维持血压的负反馈机制功效的重要决定因素。然而，其对反应的时间进程和幅度的影响仍未得到研究。
研究轻度血容量不足对健康受试者献血前后血压和心率变化的时间进程及幅度的影响。
招募了56名报名献血的健康志愿者（年龄35±7岁；体重75±9千克）。在献血前后，记录5分钟的逐搏血压和II导联心电图基线，随后进行3分钟的直立位挑战。
捐献450毫升血液并未导致静息收缩压、舒张压或平均血压发生任何变化。然而，献血后脉压显著降低，同时心率增加。在直立位挑战期间，与献血前相比，献血后收缩压、舒张压、平均血压和脉压下降幅度更大，心率增加幅度也更大。献血后反应潜伏期以及血压和心率恢复的总时间显著增加。
在捐献450毫升血液导致轻度血容量不足后，直立位挑战后的血压维持并未受到损害。然而，轻度血容量不足会导致反应潜伏期增加，并伴有直立位挑战期间更大幅度的血压下降。
