Deterioration of respiratory function is one of the major causes of critical illness and admission to critical care units. It is essential to recognise the early signs of airway and breathing difficulties and know how to manage patients who experience these problems. This chapter will discuss common causes of airway compromise and acute breathlessness and consider management of such patients using the ABCDE approach.

First Impressions

The initial view of the patient as you approach them and introduce yourself can be enlightening. It gives an overview of the patient's general condition. If the patient is sat upright with eyes open, and is able to respond appropriately without pausing to breathe in mid sentence you know that - the airway is patent, they are not in severe respiratory distress, and they are perfusing their brain.

The airway is a hollow passage carrying airflow to the areas which can exchange oxygen and carbon dioxide: the lungs. It is approximately 200mls of redundant space, which means that other than carrying air, it has no absorbent properties. This means that it has to remain clear at all times and any degree of obstruction is dangerous. This can be an incomplete, partial obstruction to a total, complete loss of patency. Such obstructions can be corrected with appropriate care, but can be made worse through inappropriate care or even lack of attention.

The common perception is that the most manageable part of the airway is the upper airway, which lies between the mouth/nose and the pharynx. It is important to remember that the airway stretches down through the larynx, trachea and bronchus to the alveoli and the lower airway can be equally managed.

Look

Look inside the mouth to see if anything is causing an obstruction. If there is mouth soiling, such as vomit, assume that the patient has aspirated. It would be dangerous to perform a blind mouth sweep in case the obstruction is worsened, but if it is safe to do so you may remove any solid foreign body visible in the mouth.

Look for condensation in the oxygen mask. The mask will appear to be steaming up and this is a good sign of air flow.

Listen

Assess for presence of speech: if the patient can speak clearly the airway is patent. Other noises can be indicative of problems with the airway.

Snoring the most recognisable noise – it happens in everyday life when people are sleeping as it is a sign of deep unconsciousness. The noise occurs when air intermittently passes over and behind the collapsed tongue, which under normal circumstances is held in place by muscles attached to the floor of the mouth. The brain regulates and controls these muscles but when the person becomes unconscious, for whatever reason, the tongue falls back against the pharynx causing life threatening obstruction.

Stridor is an inspiratory noise which comes from air flowing through the swollen, narrowed larynx. It can be caused by viral or bacterial infection, anaphylaxis or thick sputum. The underlying problem causing the stridor needs to be resolved whilst the patient is supported with oxygen therapy.

Gurgling the noise made when air is flowing back and forth over fluid. This is usually sputum, but it can also be fluid such as vomit, which can submerge the lungs or irritate them causing aspiration pneumonia. The noise can occur along the length of the airway – in the upper airway they sound like gurgles, and can be removed with a Yankeur Sucker, but they can also be heard on auscultation in the lower respiratory tract, using a stethoscope. Patients who retain secretions can become tired and at some point will deteriorate rapidly. The conscious patient needs to be re-positioned in a semi-upright position, given plenty of humidification and encouraged to take some deep breathes as the stimulus for coughing. You need to promote effective coughing but this may be difficult as it relies upon muscle strength and compliance. If the patient has a weak cough or is unconscious the doctor must be alerted urgently.

Finally, there is the presence of silence. This is a sign of complete obstruction and goes hand in hand with seesaw breathing, and is an imminent sign of respiratory arrest. This is a medical emergency.

Feel

The only recommendation is to feel for airflow by placing your cheek or hand gently over the mouth. This works on the same principle as an oxygen mask which has condensation from breathe – you can feel the airflow and occasionally the moisture from each breath.

Treat

Treat any problems you find with A (Airway) as you go along. Open the airway using head tilt, chin lift. If there are secretions in the oropharynx use the Yankeur Sucker to remove them. If the patient cannot maintain their own airway without you applying head tilt chin lift then insert an oropharyngeal or nasopharyngeal airway. Always apply 100% oxygen at A (Airway) if needed.

It is important that you have successfully managed the airway before moving onto focus upon breathing, otherwise whatever you do will be futile regardless of the correct treatment.

At a very basic level breathing describes the essential exchange of oxygen and carbon dioxide. This is described as External Respiration as it is the point when the atmosphere meets the circulation, at the interface known as the alveolar-capillary membrane. The effectiveness relies upon two working systems, the expansion of the alveoli and the flow of the blood around the lungs, the pulmonary vasculature. In practice, this is known as the V:Q ratio (V for Ventilation and Q for Perfusion) and when assessing a patient it is interesting to consider which side of this equation is being adversely affected as this will help to make sense of the deterioration.

Causes of breathlessness

Patients can sometimes be breathless without having a problem with their lungs. Some disease states cause acid to build up in the blood for example lactic acid in sepsis. The body will try and counteract this acid build up by breathing faster to blow off more carbon dioxide which is also an acid.

All tissues require oxygen for survival and oxygen delivery depends on:

• Adequate ventilation (getting sufficient amounts of air into and out of the lungs)

• Gaseous exchange (oxygen and carbon dioxide need to be able to pass from the alveoli to the blood and visa versa)

• Effective circulatory distribution of the oxygenated blood

Assessment of the breathless patient

A lot of information can be obtained about a patient's breathing from taking a general look at them as you approach them or from the end of their bed. From this initial general look you can gain valuable information, such as the patient's colour, whether they look anxious or relaxed and how hard they have to work to breathe. When you first talk to the patient you will get an impression of how easy they find it to talk. Inability to answer you in full sentences is a sign of severe respiratory distress. The look, listen and feel approach can then be effectively used to evaluate the effectiveness of breathing in more detail.

Look

Check the patient's general colour. Are there any signs of cyanosis (a blue/purple tinge around the lips?) which indicates hypoxia?

Central cyanosis is a bluish or purple tinged appearance to the lips. This occurs when there is more than 5 gm/dl of deoxygenated haemoglobin in aortic blood and is usually detectable when the arterial oxygen saturation is < 85%. It is important to remember if the patient is anaemic cyanosis may not be evident during hypoxia. Common causes of central cyanosis are acute e.g. pneumonia, asthma, pulmonary oedema, and chronic e.g. COPD.

N.B. Cyanosis is a late sign and absence of cyanosis does not mean that the patient is not hypoxic or in respiratory distress.

Look for evidence of 'see saw' breathing pattern also known as paradoxical breathing. In normal breathing the abdomen and the chest move in the same direction during inspiration (outwards) and expiration (inwards). If the airway is obstructed the abdomen and chest move in different directions so on inspiration the abdomen moves inward as the chest moves outward and for expiration the reverse pattern is seen.

Look. Is the patient alert and orientated indicating that the brain is receiving sufficient oxygen, or are they drowsy or unresponsive?

Look. Is the patient frightened and confused? Hypoxia can cause confusion. Patients in severe respiratory distress usually look very frightened and will often become restless and try to remove their oxygen mask saying that they feel the mask is suffocating them and they need air.

Look. What is the patient's posture like? are they leaning forward or are their arms outstretched gripping the cot sides tightly? Both of which can be signs of respiratory distress.

LOOK. Are they using their accessory muscles in the neck and shoulders to breathe? Or are they using their abdominal muscles?

The most sensitive indicator of deterioration in a patient is a rise in respiratory rate.

Also observe depth and rhythm of breathing.

The number of times the chest rises in 60 seconds is the respiratory rate measured as breaths per minute. The normal rate for an adult at rest is 12-18 breaths per minute. The term tachypnoea describes an abnormal fast rate of breathing, usually more than 20 breaths per minute, and is usually the first sign of respiratory distress. Bradypnoea describes an abnormally slow rate of breathing, usually less than 12 breaths per minute. If a patient's respiratory rate is very slow < 8 they may need to have their breathing supported via a bag valve mask with a reservoir bag connected to high flow oxygen.

Listen

Feel

Check if both sides of the chest are expanding. Are there any signs of surgical emphysema? Is the trachea central? Deviation may suggest pneumothorax. Does the patient's skin feel clammy?

A patient's respiratory rate may slow down appropriately in response to treatment but if the underlying problem has not been corrected a slowing respiratory rate may be an indication that a patient is becoming exhausted and moving towards a respiratory arrest.

The patients breathing pattern can be confirmed by placing hands on the chest, one on each side and checking for symmetry and regularity.

Type 1 respiratory failure: describes hypoxia with a normal or low CO₂ and is primarily due to pathology affecting oxygenation alone for example pneumonia or pulmonary embolism.

Type 2 respiratory failure: describes hypoxia with ventilatory failure which causes a high carbon dioxide level (hypercapnia). As carbon dioxide is an acid, high CO₂ levels make the blood more acidic.

The use of pulse oximetry

N.B. Pulse oximetry is a very useful monitoring tool but it does not measure carbon dioxide, this has to be monitored through the analysis of an arterial blood gas.

Whenever blood gases are taken oxygen therapy should not be removed. The amount of oxygen the patient is on when a blood gas is taken should always be recorded in the patient's notes.

Treat

Oxygen therapy

High flow oxygen and the patient with COPD

Nurses and doctors are often reluctant to give COPD patients high concentrations of oxygen in case they are carbon dioxide retainers. Carbon dioxide is our normal stimulus to breathe. If CO₂ rises we breathe more rapidly. However in a small minority of COPD patients who have high CO₂ levels all the time this no longer works and the body then uses a low oxygen level as the stimulus to breathe. If these patients have high concentrations of oxygen they may loose their stimulus to breathe and their respiratory rate will drop and their carbon dioxide levels will rise.

However in the acute situation where a patient is critically ill, it is regarded as safe practice to give high flow oxygen to all patients initially whilst you summon medical help in order to protect the patient from becoming hypoxic. Hypoxia is more dangerous than high carbon dioxide levels and will cause patients to have a cardiac arrest if severe or prolonged. The target saturation level for those with COPD is 88-92% (O'Driscoll et al. 2017).

Prevention of breathing problems

Breathing problems can sometimes be prevented. Good pain relief after abdominal or thoracic surgery helps to ensure that patients can deep breathe and cough effectively which reduces the risks of patients developing hospital acquired pneumonia post operatively. Sitting patients upright and ensuring they are pain free maximises respiratory function. If patients are stable enough sitting out of bed in a chair assists basal expansion. Relieving abdominal distension caused by a paralytic ileus or from ascites will allow the patient to breathe more deeply.

Turning immobile patients regularly not only prevents pressure sores but plays a valuable role in helping to expand different parts of the lungs and mobilise secretions. If patients are receiving high flows of oxygen for prolonged periods humidification will help prevent drying and retention of secretions. Refer any patients with breathing difficulties to the physiotherapist. Patients who are not able to get out of bed should be encouraged to perform deep breathing exercises hourly to help prevent retention of secretions, and basal collapse.

• O'Driscoll, B.R. et al. (2017). BTS guideline for oxygen use in adults in healthcare and emergency settings. Thorax, 72 (Suppl 1), ii1-ii90. http://dx.doi.org/10.1136/ thoraxjnl-2016-209729

• Patel, P.H. Mirabile, V.S. and Sharma, S. (2020) Wheezing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK482454/

• Trauma Care (2014, December 18) Anil Hormis: Trauma Care Conference 2014: Updates & Cases in ‘A’ Airway. [Video file] Retrieved from https://www.youtube.com/watch?v=_KNliNYEVWA