Low blood pressure
Learning objectives • • • • • •
What is hypotension Normal blood pressure Types of hypotension Signs & symptoms Causes of hypotension Treatment & care
What is hypotension •
•
•
•
•
Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is defined by Systolic (whether the heart muscle is contracting) & diastolic (when heart muscle is relaxed in between beats). Hypotension, the exact opposite to hypertension, is generally considered systolic blood pressure less than 90 millimetres of mercury (mm Hg) or diastolic less than 60 mm Hg. Neurologic conditions that can lead to low blood pressure include changing position from lying to more vertical (postural hypotension), stroke, shock, lightheadedness after urinating or defecating. Non-neurologic conditions that can cause low blood pressure include bleeding, infections, dehydration, heart disease, adrenal insufficiency, pregnancy, prolonged bed rest, poisoning, toxic shock syndrome, and blood transfusion reactions. defecating, Parkinson's disease, neuropathy and simply fright. Hypotensive drugs include blood pressure drugs, diuretics (water pills), heart medications (especially calcium antagonists- nifedipine / Procardia, beta blockers-propranolol / Inderal and others), depression medications (such as amitriptyline / Elavil), and alcohol.
Normal blood pressure
• • •
•
Ideally, we should all have a blood pressure below 120 over 80 (120/80). This is the ideal blood pressure for people wishing to have good health. At this level, we have a much lower risk of heart disease or stroke. If your blood pressure is optimal, this is great news. A blood pressure reading has a top number (systolic) and bottom number (diastolic). The normal blood pressure is less than 120 over 80 (120/80). Only one of the numbers low blood pressure as to be lower than it should be to count as. In other words: – if the top number is 90 or less (regardless of the bottom number) this may be low blood pressure – If the bottom number is 60 or less (regardless of the top number) this may be low blood pressure.
Types of hypotension •
There are three major types of hypotension: •
Orthostatic Hypotension - Occurs when standing up from a sitting or lying down position. You may feel dizzy or light-headed, or you may even faint. It happens if your body isn't able to adjust blood pressure and blood flow fast enough for the change in position. The drop in blood pressure usually lasts only for a few seconds or minutes after you stand up. Occur in all age groups. However, it's more common in older adults, especially those who are frail or in poor health
•
Neurally Mediated Hypotension - blood pressure drops after you've been standing for a long time. You may feel dizzy, faint, or sick to the stomach as a result. NMH also can occur as the result of an unpleasant, upsetting, or scary situation. NMH affects children and young adults more often. Severe Hypotension Linked to Shock - Shock is a life-threatening condition in which blood pressure drops so low that the brain, kidneys, and other vital organs can't get enough blood to work well. Blood pressure drops much lower in shock than in other types of hypotension. Causes are major blood loss, certain severe infections, severe burns and allergic reactions, and poisoning. May prove fatal.
•
Signs & symptoms •
•
Low blood pressure can sometimes mean there's not enough blood flowing to your brain and other vital organs, which can lead to symptoms such as: – dizziness – lightheadedness – unsteadiness, or feeling of loss of balance – fainting – blurred vision – a rapid, or irregular heartbeat (palpitations) – confusion – feeling sick (nausea) – general weakness If you experience symptoms of low pressure after changing positions, such as standing up, it is known as postural, or orthostatic, hypotension.
•
Causes... Common conditions that might result in low blood pressure : – Dehydration: Dehydration caused from diarrhoea or vomiting along with nutritional deficiency may lead to lowering of BP, which might cause you to faint or lighheadedness. – Pregnancy: Some pregnant women might experience low blood pressure during their first few weeks of pregnancy. This is due to the presence of high levels of hormone progesterone in the blood, which dilates the blood vessels – Hormonal problems: People suffering from hormonal complications such as hypothyroidism, hyperthyroidism and low blood sugar levels have been found to experience low blood pressure. – Medications: Drugs that cause hypotension include painkillers, antidepressants and medications used to treat heart diseases and anxiety disorders. – Diseases: Clinical conditions that lower your blood pressure levels include heart failure, anaemia (due to vitamin B12 deficiency) abnormal heart rate, liver disorders and anaphylaxis. In some cases, severe blood infections (such as sepsis) and widening or dilation of blood vessels may result in hypotension. – Other conditions: There is a sudden drop in your blood pressure levels due to heat stroke and changes in body temperature (low or high body temperature)
Treatment: • • • • • •
• • • •
•
•
Eat a diet higher in salt. Drink lots of nonalcoholic fluids. Limit alcoholic beverages. Visit the doctor for proper medication Get regular exercise to promote blood flow. Be careful when rising from lying down or sitting. To help improve circulation, pump your feet and ankles a few times before standing up. Then proceed slowly. When getting out of bed, sit upright on the edge of the bed for a few minutes before standing. Elevate the head of your bed at night by placing bricks or blocks under the head of bed. Avoid heavy lifting. Avoid straining while on the toilet. Avoid prolonged exposure to hot water, such as hot showers and spas. If you get dizzy, sit down. To avoid problems with low blood pressure and lessen episodes of dizziness after meals, try eating smaller, more frequent meals. Cut back on carbohydrates. Rest after eating. If needed, use elastic support (compression)like stockings that cover the calf and thigh. These may help restrict blood flow to the legs, thus keeping more blood in the upper body.