Vasoconstrictors are often given to raise blood pressure. That they do is seductively reassuring. Vasoconstrictors increase the resistance to blood flow. This raises the blood pressure by reducing blood flow. This reduction in blood flow is not apparent and is not detected even as it happens. We might see in the short term an initial rise in blood pressure which is easily measured, mistakenly reassuring, but we should expect the worsening of perfusion. We generally can’t measure or test that the perfusion is decreasing. Blissfully we are unaware of it mistakenly deceived by the increase in blood pressure.
Blood Pressure Redistribution
Blood Pressure and flow may be redistributed to different vascular beds. If the flow is redistributed to the brain this may may in the short term be noticed. In other vascular beds the worsening of perfusion will be noticed later as will an overall deterioration in the condition of circulation and perfusion. Swapping short term improvement for long term deterioration is seductive. This is true in many situations, the reversal of fortune where short term results are perceived as an overall benefit.