| Ch 16 | Page 9 / 16 | |
| Cancer emergencies |
Respiratory emergencies | |
In acute respiratory insufficiency, an important fall in arterial oxygen pressure is observed with a major increase of C02 pressure.
Clinical symptoms are hypoxia, dyspnoea, tachycardia, peripheral vasoconstriction, agitation, confusion and even obnubilation with cyanosis leading to respiratory distress.
Acute respiratory insufficiency has many causes ranging from mechanical tracheal disorders to alveoli exchange disorders or neurological disorders altering the respiratory mechanism.
A precise evaluation of the mechanisms of respiratory insufficiency is necessary to decide on a potentially efficient treatment.
Among the various aetiologies:
- Pulmonary infection related to cancer or to its therapy (chemotherapy)
- Alveolar pneumonia in relation to bacteria, virus, fungi, after radiotherapy or chemotherapy
- Carcinomatous lymphangitis,
- Swallowing disorders and endobronchial fluid aspiration,
- Multiple embolism,
- Atelectasia in relation to a bronchial tumour,
- Brain metastases or cerebral oedema with compression of respiratory centres,
- Quadriplegia,
- Pneumothorax,
- Metastatic pleural effusion,
- Major opioid intoxication with hypoventilation and hypercapnia,
A fulminating form of respiratory insufficiency syndrome may occur either spontaneously or after lengthy evolution of existing respiratory insufficiency.
It associates a very rapidly developing hypoxia, with diffuse multilobular infiltration at chest x-ray, similar to non-cardiogenic pulmonary oedema, with diminution of pulmonary compliance and arteriovenous shunt.
It is a diffuse alveolar disease and a non-specific lung reaction to major aggression.
Such acute respiratory insufficiency requires patient admission into an intensive care unit.
Its prognosis is very poor: nearly 90% of patients with lung cancer, 40% with breast cancer who are admitted into an intensive care unit for respiratory assistance die in the month following their admission. Such a high mortality rate may question the appropriateness of admission of these patients into intensive care units.
In fact, treatment is symptomatic with high oxygen supply which almost always requires endotracheal intubation, multiple aspirations, and machine-assisted ventilation in order to maintain oxygen saturation over 90%. Other cardiovascular rehabilitation measures and antibiotics are also necessary.
Cancer is the most frequent cause of massive pleural effusion which may be complicated by cardiovascular decompensation. Pleuresia is generally a sign of the incurability of lung cancers (however not for lymphoma or other highly chemosensitive cancers).
Pleural puncture can be both of diagnostic and therapeutic value with a clear improvement of dyspnoea. It can be complicated by pneumothorax, haemorrhage, empyema or cancer cell sowing along the puncture path.
In the case of frequent or rapid relapse, intrapleural chemotherapy may be proposed (if such chemotherapy is potentially effective) or simple talc pleurodesis which will allow the drying of pleural effusion over a long period of time.
We can distinguish obstruction of the upper airways (hypopharynx, larynx, trachea down to the carena) and lower airways (bronchial and lower airway).
Obstructive lesions are manifested by coughing, dyspnoea, stridor, cyanosis, atelectasia and possibly death.
Upper airway obstruction
Upper airway obstruction constitutes a genuine medical emergency.
They are due either to the intrabronchial aspiration of food or saliva, or to tracheal stenosis, tracheomalacia, oedema or a complication related to treated tumours (in particulare oedema).
Diagnosis is evoked by major inspiration difficulties with intercostal muscle retraction and major psychological distress. Acute transformation may be very rapid: the patient becomes cyanosed, unable to speak and extremely agitated before dying within a few minutes.
The endoscopic examination should be carried out quickly in order to find out the cause of the obstruction and to treat it if possible (removal of a foreign body, aspiration of a mucous mass). Occasionally, rapid tracheotomy needs to be performed.
As soon as the risk of asphyxia has been removed, all necessary measures should be taken to avoid any feared relapse of such acute obstruction.
Lower airway obstruction
It is rarely such an acute phenomenon. It is generally due to bronchial carcinoma or a metastatic endobronchial lesion.
The obstruction usually provokes hemoptysis, dyspnoea and fever with obstructive pneumonia.
Fiber bronchoscopy generally allows the evaluation of the endobronchial lesion and consequently the proposal of appropriate treatment (surgery, radiotherapy, chemotherapy or an association).
A symptomatic treatment may also be proposed (laser, endobronchial brachytherapy, endobronchial stent).
It is a common life-threatening syndrome for aged bedridden people, confused patients or patients suffering from swallowing disorders as well as those fed with naso-gastric tubes in supine position.
The risk involved in lung aspiration of a gastric liquid with a low pH, especially for intubated patients or tube fed patients, is the constitution of alveolar lesions associated with super-infection due to aspirated food.
Massive aspiration can provoke death by suffocation.
Most often, after the initial endobronchial aspiration, the patient coughs and ejects most of the inhaled material; however a few hours later, an increasing dyspnoea accompanied by coughing, fever, hypoxemia and pulmonary oedema signifies the onset of an acute respiratory distress syndrome.
Occasionally, the endobronchial inhalation of alimentary liquid remains totally unnoticed and a chronic infection appears a few days later.
Treatment includes respiratory rehabilitation, antibiotics, tracheobronchial aspiration and bronchoscopic washings with physiological fluid.
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