Anemia is not low blood pressure

WELLNEWS

Victor Romulo Gallardo Dumaguing, MD

If there are two terms in the medical world that are often mistaken for the other, it is anemia and low blood pressure, so that even schooled and educated professionals may use these two words interchangeably thinking that their listener gets their message. It’s highly probable that aggressive advertisements on the trimedia, especially television may have added to the confusion. This column wants to share its one-cent worth of statement with the hope of clarifying the issue.
     A quick look at blood pressure; factors that affect it are cardiac output and total peripheral resistance. Cardiac output in healthy adults is 5 liters of blood circulating in the entire body, which is the product of stroke volume-amount of blood ejected by the heart for its every contraction 70-90 ml; and heart rate normal 60-100 beats per minute. Thus if a person has heart rate of 70 multiplied by stroke volume of 70 would be 4900ml, close to the normal 5000ml cardiac output. From this equation, anything that increases heart rate-anger, fear, pain, would automatically increase the cardiac output raising the blood pressure. Total peripheral resistance is the force exerted on the walls of blood vessels, particularly arteries, with vasoconstriction being balanced by vasodilatation mechanisms. When one is angry the so-called sympathetic nervous system is activated flooding the entire body with hormones adrenaline and nor-adrenaline leading to stronger, faster heart beats and massive vasoconstriction increasing total peripheral resistance, thus BP goes up.
     Everybody wants to hear his/her blood pressure is 120/80; with some slight but not clinically significant variations during the day. The American Heart Association and the American College of Cardiology put the ceiling of normal blood pressure at 140/90mmHg while the European Society of Cardiology has a stricter criterion at 135/85mmHg. Medical practitioners all over the world, Filipino doctors included adhere to these guidelines.
     The numbers for the diagnosis of low blood pressure is more difficult to quantify. Females of the same age, and weight as their male counterparts generally have a lower blood pressure with their systolic readings in the range of 100-110mmHg with a diastolic pressure of 70-80mmHg. It’s not surprising even for a petite skinny lady to have a 90/60 blood pressure without having any signs and symptoms. My cardiologists-friends though say that anything lower than 90/60 should be taken seriously
     Anemia has nothing to do with blood pressure. Standard medical textbooks and hematologists-blood specialists- define anemia as “low red blood cell count, low hemoglobin count or both.
However from a strict clinical standpoint, anemia’s signs and symptoms-pallor/paleness of the conjunctiva of the eyes and other mucous membranes of the body, nail beds, palms; easy fatigability,
Fast heart rate with occasional palpitations, chest pains- are due to low hemoglobin, the protein in the surface of red blood cells that carry life-giving oxygen to the different cells of the body and a carrier of carbon dioxide from the cells to be eventually expelled in the lungs. This is not to diminish the role of the red blood cell count. However, it must be emphasized that patients with COPD-chronic obstructive pulmonary disease- common among long-standing heavy smokers who now have pulmonary emphysema and chronic bronchitis; in fact they have what is called polycythemia- an excess of red blood cell not accompanied by a proportionate increase in the more important hemoglobin carrier of oxygen, a situation which adds another problem because of hyper viscosity- increased thickness of blood which exerts additional burden to the pumping role of the heart
     Dizziness and lightheadedness are symptoms common to both patients with anemia and low blood pressure. The brain needs a constant steady supply of cerebral blood flow- 750 ml per minute, which obviously may not be supplied if the blood pressure is low especially in the upright position.
And even if blood volume is adequate, if it is not loaded with oxygen-carrying hemoglobin as in the case of anemic individuals, then dizziness is a frequent symptom. Remember just how oxygen-dependent the brain is; during CPR –cardiopulmonary resuscitation- the primary concern is to prevent the 6 minutes anoxia or
Continuous no supply or oxygen to the brain cells, to avoid making the patient going into vegetative state.
      So dear readers, I hope you don’t join some smart-alecks who would tease or taunt or laugh at someone who say he is both hypertensive and anemic at the same time. It’s very possible that the patient has both high blood pressure and at the same time quite low in his red blood cell/hemoglobin count.
Next Week: Different Types of Anemia