Hyperventilation syndrome
Encyclopedia
Hyperventilation syndrome (HVS; also chronic hyperventilation syndrome or CHVS) is a respiratory disorder, psychologically or physiologically based, involving breathing too deeply or too rapidly (hyperventilation
). HVS may present with chest pain
and a tingling sensation in the fingertips and around the mouth (paresthesia
) and may accompany a panic attack
.
People with HVS may feel that they cannot get enough air. In reality, they have about the same oxygenation in the arterial blood (normal values are about 98% for hemoglobin saturation) and too little carbon dioxide
in their blood and other tissues. While oxygen is abundant in the bloodstream, HVS reduces effective delivery of that oxygen to vital organs due to low--induced vasoconstriction
and the suppressed Bohr effect
.
The hyperventilation is self-promulgating as rapid breathing causes carbon dioxide levels to fall below healthy levels, and respiratory alkalosis
(high blood pH
) develops. This makes the symptoms worse, which causes the person to try breathing even faster, which further exacerbates the problem.
The respiratory alkalosis leads to changes in the way the nervous system
fires and leads to the paresthesia
, dizziness, and perceptual changes that often accompany this condition. Other mechanisms may also be at work, and some people are physiologically more susceptible to this phenomenon than others.
with others including infection, blood loss, heart attack, hypercapnia
or alkalosis
due to chemical imbalances, decreased cerebral blood flow, and increased nerve sensitivity may also underlie this symptom.
In one study, one third of patients with HVS had "subtle but definite lung disease" that prompted them to breathe too frequently or too deeply.
Many people with panic disorder
or agorophobia will experience HVS. However, most people with HVS do not have these disorders.
The same benefits can be obtained more safely from deliberately slowing down the breathing rate by counting
or looking at the second hand on a watch
. This is sometimes referred to as "7-11 breathing", because a gentle inhalation is stretched out to take 7 seconds (or counts), and the exhalation is slowed to take 11 seconds. This in-/exhalation ratio can be safely decreased to 4-12 or even 4-20 and more, as the O₂ content of the blood will easily sustain normal cell function (for several minutes at rest) when normal blood acidity has been restored. However, if a few minutes of this intervention are not effective, the patient should be seen by emergency medical personnel (paramedics or physicians).
Most patients benefit from carefully, deliberately slowing down their breathing twice a day for five minutes at a time. The goal is to reduce breathing to no more than five breaths per minute. This helps retrain their habits and convince them that faster breathing is unnecessary.
Hyperventilation
Hyperventilation or overbreathing is the state of breathing faster or deeper than normal, causing excessive expulsion of circulating carbon dioxide. It can result from a psychological state such as a panic attack, from a physiological condition such as metabolic acidosis, can be brought about by...
). HVS may present with chest pain
Chest pain
Chest pain may be a symptom of a number of serious conditions and is generally considered a medical emergency. Even though it may be determined that the pain is non-cardiac in origin, this is often a diagnosis of exclusion made after ruling out more serious causes of the pain.-Differential...
and a tingling sensation in the fingertips and around the mouth (paresthesia
Paresthesia
Paresthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
) and may accompany a panic attack
Panic attack
Panic attacks are periods of intense fear or apprehension that are of sudden onset and of relatively brief duration. Panic attacks usually begin abruptly, reach a peak within 10 minutes, and subside over the next several hours...
.
People with HVS may feel that they cannot get enough air. In reality, they have about the same oxygenation in the arterial blood (normal values are about 98% for hemoglobin saturation) and too little carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
in their blood and other tissues. While oxygen is abundant in the bloodstream, HVS reduces effective delivery of that oxygen to vital organs due to low--induced vasoconstriction
Vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, small arterioles and veins. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in...
and the suppressed Bohr effect
Bohr effect
Bohr effect is a property of hemoglobin first described in 1904 by the Danish physiologist Christian Bohr , which states that an increasing concentration of protons and/or carbon dioxide will reduce the oxygen affinity of hemoglobin...
.
The hyperventilation is self-promulgating as rapid breathing causes carbon dioxide levels to fall below healthy levels, and respiratory alkalosis
Respiratory alkalosis
Respiratory alkalosis is a medical condition in which increased respiration elevates the blood pH...
(high blood pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
) develops. This makes the symptoms worse, which causes the person to try breathing even faster, which further exacerbates the problem.
The respiratory alkalosis leads to changes in the way the nervous system
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...
fires and leads to the paresthesia
Paresthesia
Paresthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
, dizziness, and perceptual changes that often accompany this condition. Other mechanisms may also be at work, and some people are physiologically more susceptible to this phenomenon than others.
Causes
Hyperventilation syndrome is believed to be caused by psychological factors and by definition has no organic cause. It is one cause of hyperventilationHyperventilation
Hyperventilation or overbreathing is the state of breathing faster or deeper than normal, causing excessive expulsion of circulating carbon dioxide. It can result from a psychological state such as a panic attack, from a physiological condition such as metabolic acidosis, can be brought about by...
with others including infection, blood loss, heart attack, hypercapnia
Hypercapnia
Hypercapnia or hypercapnea , also known as hypercarbia, is a condition where there is too much carbon dioxide in the blood...
or alkalosis
Alkalosis
Alkalosis refers to a condition reducing hydrogen ion concentration of arterial blood plasma . Generally, alkalosis is said to occur when pH of the blood exceeds 7.45. The opposite condition is acidosis .-Causes:...
due to chemical imbalances, decreased cerebral blood flow, and increased nerve sensitivity may also underlie this symptom.
In one study, one third of patients with HVS had "subtle but definite lung disease" that prompted them to breathe too frequently or too deeply.
Many people with panic disorder
Panic disorder
Panic disorder is an anxiety disorder characterized by recurring severe panic attacks. It may also include significant behavioral change lasting at least a month and of ongoing worry about the implications or concern about having other attacks. The latter are called anticipatory attacks...
or agorophobia will experience HVS. However, most people with HVS do not have these disorders.
Diagnosis
Hyperventilation syndrome is a remarkably common cause of dizziness complaints. About 25% of patients who complain about dizziness are diagnosed with HVS. The gold-standard diagnostic technique is to have the patient breathe rapidly for two minutes. This will trigger the symptoms and convince the patient that overbreathing is responsible for the symptoms. This test can only be performed at a time when the patient is not already experiencing symptoms.Treatment
While traditional intervention for an acute episode has been to have the patient breathe into a paper bag, causing rebreathing and restoration of CO₂ levels, this is not advised or taught. When patients hyperventilate, they change their blood chemistry toward alkalosis. In alkalosis, hemoglobin binds more securely to the oxygen ('alkalotic O₂ clamping', also called the 'Bohr effect'), so the patient's cells become relatively hypoxic. Restricting inspired oxygen worsens this hypoxia and is detrimental to the patient. If attempting to calm the patient does not work within a few minutes, and the patient's condition is deteriorating, the hyperventilation may be caused by a medical condition (some of which are life threatening such as head injuries or drug overdose).The same benefits can be obtained more safely from deliberately slowing down the breathing rate by counting
Counting
Counting is the action of finding the number of elements of a finite set of objects. The traditional way of counting consists of continually increasing a counter by a unit for every element of the set, in some order, while marking those elements to avoid visiting the same element more than once,...
or looking at the second hand on a watch
Watch
A watch is a small timepiece, typically worn either on the wrist or attached on a chain and carried in a pocket, with wristwatches being the most common type of watch used today. They evolved in the 17th century from spring powered clocks, which appeared in the 15th century. The first watches were...
. This is sometimes referred to as "7-11 breathing", because a gentle inhalation is stretched out to take 7 seconds (or counts), and the exhalation is slowed to take 11 seconds. This in-/exhalation ratio can be safely decreased to 4-12 or even 4-20 and more, as the O₂ content of the blood will easily sustain normal cell function (for several minutes at rest) when normal blood acidity has been restored. However, if a few minutes of this intervention are not effective, the patient should be seen by emergency medical personnel (paramedics or physicians).
Most patients benefit from carefully, deliberately slowing down their breathing twice a day for five minutes at a time. The goal is to reduce breathing to no more than five breaths per minute. This helps retrain their habits and convince them that faster breathing is unnecessary.