Acute respiratory failure in a 68-year-old man

Problem 53 Acute respiratory failure in a 68-year-old man



Stephen W. Lam




Having just finished congratulating yourself for managing your last case so well, you are called to see a 68-year-old man brought into the emergency department by ambulance with severe dyspnoea. He is accompanied by his wife, who states that he has had increasing shortness of breath overnight with some symptoms of an upper respiratory tract infection for the last day or so. Over this time he has also had increasing wheeze and a dry cough with ‘tightness’ of his chest. He has become somewhat agitated this morning.

He is in obvious respiratory distress, unable to utter more than one or two words at a time.

This man obviously needs urgent assessment and treatment. You only have time to elicit the essential parts of the history while you rapidly examine the patient and start the appropriate management.



Q.1


What are the major differential diagnoses to consider immediately?


The patient’s breathing is so laboured that he is unable to answer any of your questions.



Q.2


What are the main points of further information that you would like to elicit from his wife and ambulance officers?


The man’s wife tells you that he has ‘pretty bad’ emphysema. He has no known history of cardiovascular disease.


His medications are:


• Salbutamol inhaler: 2 puffs prn (1–3 times on a typical day).

• Salmeterol: 2 puffs metered dose inhaler bd.

• Fluticasone: 500 µg metered dose inhaler bd.

• Ipratropium bromide: 2 puffs metered dose inhaler bd.

He has smoked heavily for most of his life, but has reduced his current cigarette consumption to about five a day. He does not drink and has no known allergies.


The ambulance officer states that haemoglobin oxygen saturation (measured by pulse oximetry, SpO2) has been around 80% throughout the journey, and that he has been wheezing loudly. He has been given 5 mg nebulized salbutamol in the ambulance.


As you examine the patient, you observe that on 6 L/min of oxygen by face mask, his SpO2 is 78%. He seems irritable, obviously dyspnoeic, and grasping the sleeve of your designer shirt, he utters ‘help …’.


You persist with the examination. His respiratory rate is 30 breaths per minute with a prolonged expiratory phase. The pulse rate is 110 bpm and regular. His temperature is 36.5°C and the blood pressure 110/75 mmHg. He is well hydrated and peripheral perfusion is adequate. His peripheral pulses are all present and of good volume. In the semi-recumbent position his jugular venous pulsation (JVP) is 3–4 cm above the base of the neck. Both heart sounds appear normal and there are no murmurs. His trachea is in the midline. He is barrel-chested and there are reduced breath sounds throughout. There is a diffuse expiratory wheeze and the percussion note is normal, there are no crepitations. His abdomen is soft and non-tender. His calves are normal and there is no pedal or sacral oedema.



Q.3


What investigations should be performed straight away?


An electrocardiogram is performed which shows a sinus tachycardia. His arterial blood gas (ABG) results are as follows:


Investigation 53.1 Arterial blood gas analysis















PaO2 48 mmHg
PaCO2 70 mmHg
pH 7.24
Bicarbonate 29 mmol/L


Q.4


What does his arterial blood gas show?


You adjust his oxygen therapy carefully. He is too dyspnoeic for a peak expiratory flow rate (PEFR) measure. You order an urgent mobile chest X-ray and go on to administer emergency medications to treat this man’s condition.



Q.5


What should you do immediately with his supplemental oxygen therapy?



Q.6


Outline your options for administering supplemental oxygen to his man.


A chest X-ray is performed and is shown in Figure 53.1.


image

Figure 53.1



Q.7


What does the X-ray show? What is your diagnosis?



Q.8


Describe in detail what you would use to treat this man.


The patient starts to improve, but he is still struggling. You call the intensive care team, who admit him to the intensive care unit (ICU). He receives close monitoring of his gas exchange. He is placed on BPAP (bi-level positive airway pressure ventilation by non-invasive face mask) to support his ventilation. A radial arterial line is inserted to monitor blood gases.


The patient responds almost instantaneously with BPAP, reporting a marked reduction in dyspnoea. Oxygen therapy is carefully monitored and adjusted in the ICU. Bronchodilators are continued and he is commenced on a course of oral prednisolone beginning with 50 mg daily. His blood gases stabilize with improvement in his respiratory condition, achieving almost his baseline level of function over several days with PaO2 65 mmHg on 1 L/minute via nasal cannulae, PaCO2 53 mmHg, pH 7.38, bicarbonate 28 mmol/L.


He is discharged after 7 days in hospital to complete a 10-day course of prednisolone (dose to be tapered according to clinical progress), a programme for respiratory rehabilitation and to discontinue smoking, and follow-up appointments in the respiratory medicine clinic with pulmonary function testing.



Answers


A.1 In the absence of an obvious external cause (e.g. chest trauma, upper airways obstruction), the vast majority of cases of acute shortness of breath in adults will be due to one of four conditions:


• Exacerbation of chronic obstructive pulmonary disease (COPD) or asthma.

• Pneumonia/lower respiratory tract infection or irritation (such as aspiration).

• Pulmonary embolism.

• Pulmonary oedema (it is important to look for the underlying causes, e.g. myocardial ischaemia or cardiac arrhythmia, and non-cardiogenic causes).

Spontaneous pneumothorax, while much less common than the conditions above, is also an important diagnosis to consider.


Anaemia and metabolic acidosis may also cause tachypnoea and, along with pulmonary embolism, should be sought particularly in patients with normal-appearing plain chest radiograph.


A.2 You will need to have:


• A brief account of what has happened since the onset of his illness, including his condition on arrival of the ambulance officers and any treatment given so far. It is important to know the current trend of his condition (e.g. rapidly deteriorating, stable, improving, etc.) and response to treatment, as this can give you important clues to the diagnosis and vital information on the urgency and aggressiveness of intervention required.

• A ‘problem list’ of his active and inactive medical conditions.

• A list of his current medications.

• Information about any allergies.

A.3 The most important immediate investigations are:


• Arterial blood gas (ABG) analysis.

• Mobile chest X-ray.

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Apr 2, 2017 | Posted by in GENERAL SURGERY | Comments Off on Acute respiratory failure in a 68-year-old man

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