Risk of Hypotension

Risk of Hypotension

a group of people was asked to close their eyes and relax. After a minute, they were told that a poisonous spider was crawling up the wall towards them. They had to open their eyes for three seconds to swat it away with a magazine before resuming their ‘relaxing’ activity.

These people would say that they saw the same number of spiders as those who had not been under stress beforehand. However, if you *did* see one more spider after being stressed out, what does this tell us about the heightened perception of risk?

The heightened perception of risk is due to an increased awareness of stimuli in the surrounding environment induced by stress hormones which lead to overestimation of these stimuli. This increase in risk perception can be affected by many physiological factors; the cardiac output, respiratory rate, and muscular response could all cause this heightened risk perception.

causes of hypotension:

1. Fear

2. Hypovolemia(blood volume deficit)

3. Vasodilation(relaxation of blood vessels)

4. High cardiac output(this is bad…it must be below…)

5. Pain relief medicines

6. Hypothyroidism -slow heartbeat, decreased blood volume, dilated blood vessel’s( to feel cold)

orthostatic hypotension:


2. Inactivity(lying down)

3. Exposure to cold weather…not for people who live in tropics but, if they get out of it and their body temperature drops so much the heart struggles to pump blood up to the brain which will result in a fainting spell or a worse scenario is brain damage due to lack of oxygen going up there.

4a.Pregnancy – not recommended since this stresses your heart a lot and during pregnancy, you have a high progesterone level that relaxes smooth muscles around your blood vessel’s..this puts pressure on the vessels…hence, less blood flow going up towards the brain…in other words, you can easily faint while pregnant(no offense meant).

5. Fluid replacement ( if you are sweating like crazy or vomiting like there is no tomorrow..you need to get drops of salts and liquids).

6. Smoking(it relaxes your blood vessel)

what is dangerously low blood pressure:

1. 30/10, this is when you have a blood pressure of 30 over 10…it is too low…

2. lower than 90(in most cases the patient will be in a coma)

3. 60/30 or less..this can cause brain damage and death if not attended to immediately

hypotension treatment:

1. If blood pressure is on the high side…get fluids to infuse(if they can afford it)

2. Vasoconstriction – using medications to constrict the blood vessels ( this will help but, not in most cases because, most of these drugs are very expensive and most people don’t have access to them).

3. If low..give saline infusion(as mentioned above) + dopamine drip(for kidney failure patients but, can be used for hypotension too)

4. Blood transfusion / artificial oxygenation ( this is urgent if patients don’t respond to treatment or if they are unconscious).

5. O2 mask/humidified air

6a.CPR (cardiopulmonary resuscitation) if the patient is not responding and there is absolute unresponsiveness(a flat line for the pulse is a sure shot indication that, CPR is needed).

low blood pressure:

1. Shock – the patient will be pale, cold but sweaty and clammy( because vasoconstriction is there), rapid heart rate, low blood pressure, oxygen deficiency which may lead to death.

2. Hypovolemia – this is when there is a large amount of fluid lost e.g vomiting, diarrhea, and so on…this causes hypotension and the skin will be moist and cold due to vasodilation(relaxation of blood vessels).

3. Vasodilation- same as above but in vasodilation it happens gradually not suddenly like shock…the patient also has little sweating/clammy feeling

4a. POTS – postural orthostatic tachycardia syndrome..when your body is in an upright position, blood rushes to your head…this makes the heart work harder so it speeds up…hence when you suddenly change positions(from lying down or sitting to standing) this causes a sudden drop of blood pressure and the reflex regulates by speeding up which in turn increases the risk for cardiac arrest.

4b. Inactivity -lying down after a while results in the same effect as above- blood rushing to the head but not much regulation takes place….hence, low blood pressure.

5a. Lying down – when you are in bed all day long..you suffer from hypotension because there is no gravity reshaping your vessels….they become very loose due to lack of usage hence; less blood flow resulting in low blood pressure.

5b. Sudden change in positions – when you stand up after lying down for a while, your body position changes which causes a sudden drop in blood pressure since there is no regulation to compensate for the loss of gravity on your veins and arteries..hence, hypotension.

low bp symptoms:

1. When you have low blood pressure most of the time, it causes headaches and nausea..these are symptoms of hypotension.

2. Vomiting/diarrhea…it is a signal from your body that you need more fluids to compensate for the lost liquids…this causes further lowering of blood pressure resulting in dizziness, vision problems, and other health complications like; seizures, stroke, etc

3a. Dizziness-the center of balance is controlled by your cerebellum( which is responsible for equilibrioception)…when there is not enough fluid around hence; lower blood pressure..that part will slow down causing imbalance.

3b. Vision problems-imbalance affects the ability to concentrate on what you see hence; you cant focus and this causes headaches and dizziness…vision problems is a symptom of hypotension

3c. Seizures- there is not enough glucose around the brain cells because there are no sufficient liquids( see dehydration)….this affects cognitive functions..cognitive functions regulate neuronal excitability hence; seizures

4a. Stroke – when blood pressure drops too much or too often, it can cause stroke due to oxygen deficiency….in case of a stroke…always perform CPR first before doing anything if possible(if they are having a heart attack also).

4b. Other complications – diabetes, renal failure, PTSD asthma attacks, etc.. asthma attack is caused by low blood pressure since the fewer amount of nutrients go to your lungs as a result of hypotension…

5. Pulse – when you are in hypotension most of the time, your pulse becomes weak and thread…this is a sign of low blood pressure.

low blood pressure causes:

Any overactive thyroid gland. The release of thyroxine stimulates many processes in your body, including increased heart rate and rapid or forceful contractions of the heart muscle (cardiac output).

The increase also raises your metabolic rate, which can lead to lower than normal blood pressure. Although this effect is usually mild, it may be severe enough to cause symptoms such as fatigue and weight loss. This disorder can easily be treated with medications that reduce thyroid activity.

Normal blood pressure:

Normal blood pressure is defined as a systolic reading of between 100-129 mmHg and a diastolic reading of 60 or less.

7. Diagnosis:

The diagnosis of hypotension relies on the person’s signs, symptoms, history, physical examination findings, blood tests, electrocardiogram (ECG), and echocardiogram (echo). Blood tests may reveal low levels of sodium and chloride, which can be associated with dehydration.

Electrolyte imbalances may also be seen in chronic heart failure and liver disease. An ECG will show abnormal conducting pathways that reflect damage to the myocardium. Echo may show dilation of the left ventricle, reduced ejection fraction and decreased myocardial contractility.

8a. Treatment:

treat hypotension by having the patient lie down if she is feeling faint or dizzy, rate her pulse, and inspect for signs of shock. Make sure the patient is warm and comfortable. Administer oxygen if available. If she has hiccups, ask her to take a few deep breaths. The rise in esophageal pressure can stop hiccups, which are not dangerous but may further lower blood pressure.

If the patient has nausea or vomiting or excessive sweating, move her to a cool area with fans or air conditioning, raise her feet slightly higher than the level of her head, and offer antacids. Treat shock promptly by raising the person’s legs about 12 inches (30 cm) and keeping her warm. Administer oxygen if available, and keep the patient calm.

8b. Prevention :

eat foods with high sodium content to help your body retain fluid… this includes fruits as well as vegetables(e.g., celery , cucumbers , lettuce ). In addition, avoid caffeine as it causes the loss of liquid from the bloodstream.- drink 3 liters of water a day- exercise daily- take more salt during summer months

9a. Diagnosis :

The most common cause of hyponatremia is dehydration . This condition can also result from excessive use of alcohol or having a psychiatric disorder that causes excess fluid intake without adequate salt replacement, such as anorexia nervosa. In some cases, hyponatremia results from increased secretion of vasopressin (antidiuretic hormone). This can be caused by a hypothalamus disorder or as a side effect of certain drugs.

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