hyperventilatingJohn Laszlo presents a detailed analysis of hyperventilating in practice.

Moving on from the common faint, the next medical emergency is the hyperventilating patient. This patient often appears either in, or after, a state of panic.

In many ways there are similar triggers to the faint, with anxiety being the most common of these. It is a frequent occurrence in the dental practice and can be extremely distressing for the patient. Only very rarely can hyperventilation lead to complications but only if this medical emergency is not managed correctly.


The patient will feel dizzy and may complain of being anxious or fearful. Not only of the dentist or clinician, but of what they think you are about to do to them.

The patient will have tingling or numbness in the face, hands and feet. This is even before you have laid your healing hands on or near them.

Signs to look for

  1. The patient will be rapidly breathing
  2. A flushed appearance
  3. The patient’s pulse will be rapid
  4. There will be tetany and spasticity of the hands and possibly the larynx too
  5. With laryngeal spasm, the patient’s airway can become obstructed. And this may lead to cerebral vasoconstriction, with collapse of the patient rapidly following from this.

Under no circumstances should you treat a dental patient who is hyperventilating as anything less than a medical emergency.



Your calming, professional and reassuring approach to all patients should reduce to a minimum, if not completely eliminate the presentation of this medial emergency from your dental clinic.

If a patient starts to hyperventilate, then stop whatever you are doing, that may have initiated the hyperventilating.

Perhaps you were trying to gain consent for an extraction of a periodontally involved tooth. However, to the patient your explanation came across as nothing less than a radio hemo-headectomy.

Even trying to explain the need for a hygiene appointment to a nervous patient may seem like a horrible message of doom.

Therefore, a calming empathic approach, with a modicum of sympathy as you are carefully and actively noting the effect your words are having on the patient, is essential to avoid a panic attack and ensuing hyperventilation.

If a patient starts to hyperventilate, then soon after stopping whatever you were doing that was scaring the patient, gently lift the patient’s hands to their mouth and while cupping their hands (not yours) to their mouth, get them to breathe into and out of their cupped hands.

Whatever you do, do not put your hands over their mouth. That can be taken as restraint, rather than reducing their radially raised respiratory rate. And it will only increase it further.

The paper bag method

At present, there is a perceived wisdom and a widely accepted opinion that a patient who is hyperventilating should re-breathe into a paper bag (Greenwood, 2009; Thornhill et al, 2010).

However, there is not a paper bag in your dental practice emergency drug box. Thinking about this critically, can we accept that the attempting to attach a paper bag to a hyperventilating patient’s head is perhaps as likely as Scotland winning the football world cup, but we live in hope it just might be possible.

But returning to hyperventilation; convincing your distressed patient to breath into and then out of a paper bag could be clumsy as well as difficult to do and possibly dangerous too.

Certainly, in 2017 the British Thoracic Society Guidelines did not recommend this practice, saying: ‘Re-breathing from a paper bag can be dangerous and is not advised as a treatment for hyperventilation (BTS guideline 8.13.3, 2017).

Traditionally, re-breathing from a paper bag was thought to allow carbon dioxide levels in the blood to normalise, but doing so can cause hypoxaemia with potentially fatal consequences (Callaham, 1989).

Good practice points to considering, then either diagnosing or excluding organic illness in the hyperventilating patient and from monitoring of oxygen saturation to take place.

Despite the evidence…

The accepted wisdom of using paper bags remains entrenched in academia, embedded in dental schools and ingrained in textbooks on medical emergencies, where drawing (not photographs) representing such a procedure can be found (Thornhill et al, 2010). Certainly, if it works and you can find evidence to support this technique, then a paper bag must be placed in the dental practice emergency drug box.

However, in the absence of a paper bag, then please apply the evidenced approach and support your patient by holding their cupped hands in yours.

More than anything else, your empathic manner reduces hyperventilation away from a potential medical emergency and towards an occurrence that can be entirely and easily managed.

Physiology of the hyperventilating patient

A patient who is hyperventilating is not breathing in either a coordinated or efficient manner. There will be rapid inspiration and expiration of air both into and out of the lungs and the stomach too.

Given the different concentrations of oxygen and carbon dioxide in the air, more carbon dioxide will leave the blood across the alveolar membranes than will be normally produced by the body. The pH of blood will rise, for example it becomes more alkaline and a state of respiratory alkalosis results, producing the tingling sensations, the dizziness and other symptoms.

In extreme case, the involuntary muscle contractions or carpo-pedal spasms will result in uncontrolled movement of hands and feet. Only in very rare cases can laryngeal spasm and airway obstruction occur. However, this is an exceedingly rare complication of hyperventilation.

In contrast to fainting, with hyperventilation, the alkalosis results in blood vessel wall constriction. Cerebral blood flow will then rapidly drop. Loss of consciousness does not often follow, as the cerebral hypoxia results in blood vessel dilation and an adequate blood flow returning.

Alkalosis reduces the respiratory rate and then breathing slows down as the blood gas ratio of oxygen to carbon dioxide normalises again (Scully, 2010).

Physiology of the hyperventilating patient

An adult at rest will have a respiratory rate of eight-14 breaths per minute and a mean tidal volume of 500mL per breath. The arterial carbon dioxide tension, the Pa CO2 is maintained between 4.6 and 6.0 kPa. A useful definition of hyperventilation is that the patient is breathing at a rate in excess of their metabolic requirements (Jack et al, 2004).

A further description is: an increase in alveolar ventilation that is more than the level required to maintain an ideal balance of blood gasses. This will results in a fall in Pa CO2 and the development of respiratory alkalosis. Hyperventilation is not the same as tachypnoea, as patients may have an increased respiratory rate but a low tidal volume, thus maintaining a normal Pa CO2.

Despite such physiological explanations, the precise mechanisms behind hyperventilation remain controversial and are often considered to be either, the result of anxiety, hypochondria or both (Gardner, 1996). Alternatively, in those patients displaying chronic idiopathic hyperventilation, there could be a resetting of the patient’s sensitivity to their CO2 levels (Jack et al, 2004). Hyperventilation may also be present in patients with chronic respiratory or cardiac disease that is either well-controlled or subclinical.

A mixture of symptoms

There are three forms of hyperventilation and patients can present with a mixture of these (Robson, 2017).

These include:

  1. Acute hyperventilation, which is episodic and often termed a panic attack
  2. Chronic hyperventilation during which the Pa CO2 is always below the normal range but the patient may nevertheless experience a few symptoms
  3. Hyperventilation during or immediately after short intense periods of exercise.

The hyperventilation syndrome

Hyperventilation can be considered as a syndrome of over-breathing when the body does not need more oxygen, yet received it. This may be either chronic or recurrent. Your patient associates this syndrome with symptoms which they report as very frightening and unpleasant but if managed correctly, are not harmful.

The hyperventilation syndrome is very common. It’s reported more in females in the age range of 15-55 and in asthmatics. Strong emotions such as anger, fear, excitement or panic can induce hyperventilation (Lenfant, 2010). As noted  above and for your memory: hyperventilation causes the concentration of carbon dioxide normally carried in your blood to drop rapidly leading to the sensations and symptoms you will see.

Symptoms of hyperventilation syndrome

  1. Respiratory symptoms: breathlessness, chest tightening with fast and frequent breathing
  2. Tetanic symptoms: a feeling of tingling in the fingers, arms and mouth, muscle stiffness and trembling in the hands. In addition, the hands and feet can become quite cold with shivering
  3. Cerebral symptoms: dizziness, blurred vision, faintness and headaches. In addition there can be fatigue, lethargy and a feeling of tense anticipation, even a feeling of impending death
  4. Cardiac symptoms: palpitations, irregular heart beat and tachycardia
  5. Gastrointestinal symptoms: sickness and abdominal pains.

Should your dental patient present with these symptoms, deal with them as outlined above. In addition, it then becomes incredibly important to exclude any other more serious and life threatening causes. The main cause of the hyperventilation syndrome is anxiety from stress. A dental patient could be a natural worrier and that can be their normal mental state. Or there may be a recent stressful life changing event such as a bereavement or any incident that was perceived as being life-threatening that can lead to hyperventilation becoming a chronic feature of their lives.

Different people respond to stress in different ways. People who hyperventilate often tense their upper thoracic musculature in response to stress. As a result, the ability of their diaphragm to function fully and freely will be limited. In turn, this places additional pressure on their already tense thoracic muscles to maintain a normal breathing pattern. After only a few minutes, the overuse of these muscles leads to the feeling of breathlessness, tightness in the chest and even a sensation of suffocation.

The innate reaction to these unpleasant symptoms is to hyperventilate; breathing becomes rapid, shallow and ineffective and a state of deep anxiety follows. Patients also report stress and frustration with their symptoms. A cycle of worsening symptoms leads to further hyperventilation and irregular breathing.

Treatment of the hyperventilating patient

You must recognise the symptoms of hyperventilation and then control them. While the symptoms are very real and are unpleasant, they are not immediately life-threatening.

Controlling the symptoms of hyperventilation is often a matter for the patient’s personal management.

You can cope with and control hyperventilation with breathing and relaxation exercises.

Firstly, it is necessary to cope with hyperventilation.

Secondly, it is necessary for the patient to be in control of potentially stressful situations.

Physiotherapists, clinical psychologists and specialist nurses can all provide the necessary input to help the patient to develop the desired breathing and relaxation skills to prevent hyperventilation.

For our patients and perhaps and perhaps ourselves, learning to breathe slowly and deeply is especially important for people who are at risk of hyperventilating. This means breathing with the chest muscles and not just the diaphragm.


Gardner WN (1996)The pathophysiology of hyperventilation disorders. Chest 109:516-534

Greenwood M (2009) Medical emergencies in dental practice: 2 management specific medical emergencies. Dental Update June 36(5):262-4,266-8

Jack S, Rossiter HB, Pearson MG (2004) Ventilatory responses to inhaled carbon dioxide, hypoxia and exercise in idiopathic hyperventilation. Am J Respir Crit Care Med 170:118-125

Lenfant C (2010) Chest pain of cardiac and non-cardiac origin. Metabolism Oct 59

Robson A (2017)  Dyspnoea, hyperventilation and functional cough: a guide to which tsts help sort them out. Breathe 13(1):45-50

Scully C (2010) chapter 1: Medical emergencies, managing emergencies in medical problems in dentistry 6th edition pp7-8. Edinburgh. Churchill Livingstone

Thornhill MH, Pemberton MN, Artherton GJ (2010) Medical emergencies in the conscious patient. Management of Medical emergencies for the dental team 2nd edition pp54-55 London S Hancocks Ltd