PNEUMOTHORAX

LOOK FOR (1)

Difficulty with ventilation/respiratory distress
Desaturation
Hypotension
Heart rate changes
Unilateral chest expansion
     Expose, inspect, palpate (2)
     Auscultate, percuss
Abdominal distension
Distended neck veins, raised CVP
Tracheal deviation

PRECIPITATING FACTORS (3)

Any needle or instrumentation, even days previously (4)
     In or near the neck or chest wall
     Down the trachea/bronchial tree
External cardiac compression
Fractured ribs, crush injury
Blunt trauma/deceleration injury
Problem with pleural drain already sited
Airway overpressure, obstructed ETT
Emphysema or bullous lung disease
Vigorous coughing followed by hypoxaemia (5)

EMERGENCY MANAGEMENT

Inform the surgeon
Turn off the nitrous oxide
Inspect the abdomen, or the diaphragm from below if visible
Insert an IV cannula into the affected side (6)
Insert a pleural drain at the same site (7)
Continuously observe the bottle for bubbling and/or swinging
Be vigilant for further deterioration in the patient; it may be due to:
     Increased or continuing air leak
     Kinked/blocked/capped/clamped underwater seal drain
     Contralateral pneumothorax
     Misplaced pleural drain tip
     Trauma caused by drain insertion
     Misconnection of drain apparatus

FURTHER CARE

If the problem persists, consider cardiac tamponade
Consider pericardiocentesis and/or opening the chest.
Arrange a chest X-ray (8) and look for:
     -state of re-expansion of the lung
     -mediastinal shift
     -position of the tip of the drain
Explain the nature of the problem to the patient before discharge from the recovery ward.
See  - After the Crisis

NOTES:
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The figures reported here are based on an analysis of 24 confirmed cases of pneumothorax reported in the first 4000 AIMS anaesthesia incidents.
(1) The diagnosis is one of exclusion.
In 63% of 65 incidents where the diagnosis was considered, it was not the cause. 71% of the confirmed cases occurred under general anaesthesia: Detection in this subgroup was by - hypotension 47%, desaturation 41%,
NOTE:: Clinical observation is NOT reliable. See (2).
The commonest cause of unilaterally decreased breath sounds is endobronchial intubation.
(2) A sign for tension pneumothorax described in the Russian literature should be specifically sought. This involves detection by palpation of widening of the intercostal spaces on the affected side. Demonstration of the sign requires that the patient be positioned symmetrically. The tips of one or two fingers are then inserted in the mid axillary line and a comparison is made from one side to the other at an identical level. The wider side has the pneumothorax. (Ref: Tsarev NI, Pugachev AF, Shelest AI. Diagnosis and treatment of spontaneous pneumothorax. Voen Med Zh 1987;8:51-52.)
(3) Following chest wall/clavicular region blocks - 25%; Whilst under general anaesthesia - 71%. Of the GA sub-group: Post CVC insertion - 41%. Associated with tracheostomy/base of neck procedures - 24%.
(4) Cronen MC, Cronen PW, Arino P, Ellis K. Delayed pneumothorax after subclavian vein catheterisation and positive pressure ventilation. Br J Anaesth 1991; 67:480-482.
(5) Choy MCK, Pescod D. Pneumothorax in association with spontaneous ventilation general anaesthesia – an unusual case of hypoxaemia. Anaesth Intensive Care 2007; 35(2): 270-273.
(6) Do not wait for confirmation by chest X-ray if the patient is rapidly deteriorating [see (7) below]. Insert the cannula just cephalad to the third rib in the midclavicular or midaxillary line, and swiftly withdraw the needle as its tip may lacerate a moving lung.
(7) Emergency management of severe trauma (EMST) recommends underwater seal drain placement just anterior to the midaxillary line, as this avoids the internal mammary artery which may be punctured using the mid-clavicular approach, and allows drainage of blood.
Always use blunt dissection to penetrate the parietal pleura. Use of finger to sweep away any structures near the opening and then insert the drain.
(8) It should be noted that a chest X-ray may not detect a non-tension pneumothorax in a supine patient. Inspiratory AP and lateral views are preferable; a CT scan is the definitive test.

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