65.6 Flail chest

This is one of the really grave emergencies. If a patient is thrown forcefully onto the steering wheel of his car, it may push in part of his rib cage, and break several of his ribs at the front and the back. These fractures may be so aligned with one another that they isolate part of his chest wall. When he inspires, this part of his chest wall moves inwards also (paradoxical movement). He breathes with difficulty, because air can now move from one lung to another, instead of being exhaled. The result is dyspnoea, hypoxia, cyanosis, and carbon dioxide retention, which are especially dangerous if he is older or bronchitic. Multiple fractured ribs cause such great pain and muscle spasm that he tries not to cough. This encourages fluid to collect in his lungs and further spoils their function. Tragically, paradoxical respiration is often overlooked.

Figure 65.9: THE MECHANISM OF A FLAIL CHEST. When the patient inspires and his chest expands, the flail section sinks in, and his mediastinum moves towards the normal side. When he expires, the flail section moves out and his mediastinum moves to the other side. The dotted lines show some air moving uselessly from one lung to the other. All this greatly impairs his ability to ventilate his lungs. Adapted from an original painting by Frank H. Netter, M.D. from THE CIBA COLLECTION OF MEDICAL ILLUSTRATIONS. Copyright by CIBA Pharmaceutical Company, Division of CIBA–GEIGY Corporation.

A patient’s fractured ribs may be anywhere. Sometimes, the front or side of his chest moves paradoxically. Or, he may extensive fractures on either side of his spine, which allow large part of his chest wall to be pulled downwards by his diafragm. Paradoxical movement is less severe when he has fractures at the apex of his rib cage, or under his scapulae, because shoulder girdle can splint his broken ribs.

Many broken ribs bleed severely, and cause a large pneumothorax. Sometimes, a patient’s underyling lung is injured so that he has a pneumothorax, perhaps under tension.

The best way of treating the paradoxical movement caused a flail chest is to use internal pneumatic fixation with IPPR, intubation, and tracheostomy. This has to be continued for several weeks while a patient’s ribs unite. IPPR has the added difficulty that it should be combined with careful monitoring of his blood gases. Even if he is skillfully nursed on a respirator, the results of treatment are not good. If IPPR is impractical, you have two alternatives:

(1) You can intubate a patient and control his respiration with a self–inflating bag, while you transfer him to a larger hospital, which has a ventilator.

(2) You can try to fix the floating segment of his chest wall by applying some form of traction for several weeks. Bilateral flail chest is usually fatal without IPPR. But you may be able to treat a patient with a unilateral flail chest, provided he has no serious injures inside his thorax. Unfortunately, most of these patients die. But, if a patient does survive the immediate injury, his outlook is good. Even a permanent dent in his rib cage is unlikely to be important.

A tracheostomy sometimes helvs.