Page 613 - ACCCN's Critical Care Nursing

590 S P E C I A LT Y P R A C T I C E I N C R I T I C A L C A R E

patient population or age group and are encountered oxygen. Any potential detrimental effects are uncommon,
in patients across the lifespan. While dyspnoea is and concentration and time dependent with a slow onset;
commonly associated with respiratory conditions such this allows for monitoring (pulse oximetry, ABG analysis)
as asthma, pneumonia, chronic obstructive pulmonary and clinical review. 55,57
disease (COPD) and cardiac conditions, it has multiple
aetiologies and related to disease in almost any organ
system. A complaint of SOB is a significant symptom CANDIDATE DIAGNOSES AND MANAGEMENT
and is commonly associated with the need for hospital The common diagnoses related to patients who present
admission. 53-55 to ED with shortness of breath are asthma, respiratory
failure and pneumonia.
ASSESSMENT, MONITORING
AND DIAGNOSTICS Asthma
On arrival, patients with respiratory complaints are Asthma is a very common patient presentation to Austral-
assessed quickly using the ABC approach to determine asian EDs. Over 2.2 million Australians have asthma,
any potential life-threatening disturbance that requires with 16% of children and 12% of adults affected by the
immediate medical assessment and/or resuscitative inter- condition. 58-61 Asthma is a chronic inflammatory disease
vention. Initial assessment includes a thorough history of the airways with many cells and cellular elements
focused on the presenting complaints. A detailed history playing a role (mast cells, eosinophils, T lymphocytes,
often identifies the underlying process; however a high macrophages, neutrophils and epithelial cells). Inflam-
index of suspicion should be maintained for other poten- matory changes cause recurrent episodes of wheezing,
tial causes during initial assessment. 53,54 History focuses breathlessness, chest tightness and coughing associated
on the nature of symptoms, the timing of onset of symp- with widespread reversible airflow obstruction of the
toms, associated features, the possibility of trauma or airways. This airflow obstruction or excessive narrowing
aspiration and past medical history (particularly the pres- results from smooth muscle contraction and swelling of
ence of chronic respiratory conditions). During physical the airway wall due to smooth muscle hypertrophy,
examination, the patient assumes a position of comfort inflammatory changes, oedema, goblet cell and mucous
while inspection of the chest is undertaken, followed by gland hyperplasia and mucus hypersecretion. 61
auscultation, palpation and percussion (see Chapter 13 Normally, airways widen during inspiration and narrow
for more detail).
in expiration. In asthma, the above responses combine to
Patients with significant respiratory symptoms are best severely narrow or close the lumen of the bronchial pas-
managed in an acute monitored bed or resuscitation sages during expiration, with altered ventilation and air
area of the department. An initial set of observations trapping. 58-60 The causes of asthma are related to many
58
including heart rate, respiratory rate, blood pressure, factors, including allergy, infection (increased reaction
temperature and oxygen saturation is supported by con- to bronchoconstrictors such as histamine), 58,59 irritants
tinuous monitoring heart rate and oxygen saturation. (e.g. noxious gases, fumes, dusts, dust mites, powders),
Pulse oximetry plays an important role in the monitor- or heredity (although the exact role or importance of any
ing of the patient with a respiratory complaint, as rec- hereditary tendency is difficult to assess). 59
ognition of hypoxaemia is significantly improved when A patient usually has a history of previous asthma
it is used. 56
attacks. Often, an acute episode follows a period of
IV access enables collection of venous blood samples for exercise or exposure to a noxious substance, or a known
full blood count (FBC) and urea, electrolytes, creatinine allergen. 58,60 The onset of the asthma may be charac-
(UEC) where clinically indicated. A chest X-ray (CXR) is terised by vague sensations in the neck or pharynx,
ordered in most instances, and interpreted in relation to tightness in the chest with breathlessness, loose but
55
the clinical history and other examination findings. Spi- non-productive cough with difficulty in raising sputum,
rometry or peak flow measurements enable assessment difficulty breathing, particularly on expiration, with
of peak expiratory flow rate (PEFR), forced vital capacity increasing severity as the episode continues; apprehen-
(FVC) and forced expiratory volume in 1 second (FEV 1 ), sion and tachypnoea may follow as the patient becomes
to determine the nature and severity of the underlying hypoxic, with audible wheezing. 58,60 The characteristics
respiratory condition. These tests are however effort- and and initial assessment of acute mild, moderate and
technique-dependent and may not be able to be per- severe/life threatening asthma in adults and associated
55
formed by a patient who is acutely SOB. An arterial clinical management guidelines are outlined in
blood gas (ABG) is often indicated in patients with a Table 22.5. 61,62
significant respiratory presentation, and provides infor- Be alert to the high-risk patient whose ability to ventilate
mation on oxygenation, ventilation and acid–base is impaired: this is a life-threatening condition. These
status. 55
patients will exhibit an inability to talk, central cyanosis,
Oxygen therapy is commenced early for a patient present- tachycardia, use of respiratory accessory muscles, a silent
ing with signs of acute respiratory compromise, including chest on auscultation, and a history of previous intuba-
those with chronic obstructive pulmonary disease tion for asthma. 55,57-59 See Chapters 14 and 15 for ongoing
(COPD); importantly, patients with acute hypoxia require management.