The respiratory topics discussed in Parts I and II dealt with problems that could occur on board with the same or even less frequency as they would on land. In Part III, however, we will examine two related respiratory emergencies that have a higher likelihood of occurring in the marine environment. In this section we will discuss chest trauma, specifically rib fractures and a collapsed lung (pneumothorax).
Before going over these problems in depth, a brief review of breathing mechanics is in order. Respiration is merely the movement of air in and out of the lungs. In this cycle, oxygen is exchanged for carbon dioxide in the tiny air sacks of the lung (alveoli) and then the oxygen is transported to the cells of the body.
The components that make up the respiratory system include the airways (trachea, bronchi and bronchioles), the lungs, the diaphragm and the thoracic cavity (including the ribs and chest muscles). In addition, a lining known as the pleura covers the lungs themselves. This lining folds back on itself and covers the inside of the chest cavity. Between the lung pleura and the chest pleura, there is a small space that is filled with fluid, which allows the lungs to move back and forth within the chest with virtually no friction. The mechanics of the respiratory cycle are based on changes in pressure. When we breathe in (inspiration), the diaphragm moves downward and the chest muscles retract to pull the ribcage outward. These coordinated movements increase the internal volume of the thoracic cavity and thereby decrease the pressure within the chest (there is actually a negative intrathoracic pressure). Since a gas (air) will flow from an area of higher pressure to an area of lower pressure, air will move from the outside the body through the airways to an area of lower pressure inside the lungs. When breathing out passively (expiration), the respiratory muscles simply relax and air moves back out. Knowing how this cycle works will make it easier to understand the specifics of lung injuries.
Trauma to the chest is not an uncommon injury suffered by the sailing population. While I do not have specific statistics on the number of chest injuries occurring in the offshore environment, personal experience would indicate that chest trauma is a problem you will eventually have to deal with if you venture offshore with some frequency. The vast majority of these injuries are not life-threatening and even the more severe injuries can be managed effectively until the sailboat makes landfall.
While I once viewed stanchions, winches and Dorades as equipment specifically designed to cause damage to toes and feet, I now see them as potential culprits for chest injury--especially in heavy weather. The on-deck environment during rough conditions is fraught with hazard and even a harnessed and tethered crewmember can lose his or her footing and be thrown against one of the aforementioned structures. Below decks is not much better, if at all. While below, we are typically not harnessed (though you should be) and more importantly, we are not as keenly aware of impending boat motion since we do not constantly look out the ports to anticipate the next wave collision. Impacting the chest against a solid object can easily generate enough force to cause significant chest trauma.
Probably the most common injury is a chest-wall contusion. This is basically a bruise to the thorax without any damage to the underlying structures. A chest contusion, while painful, will rarely result in difficulty breathing or compromise of the respiratory cycle. Beyond a contusion, a rib fracture will result if sufficient force is concentrated in a small area, such as striking a solid vertical object. A rib fracture should be suspected if the patient has had a significant blunt injury to the chest and has chest-wall pain at the site of impact with deep inspiration, movement and/or palpation of the area. There may also be crepitus (a grating sensation) at the fracture site when palpated. The management of an uncomplicated rib fracture centers on pain relief and prevention of further complications.
Narcotic analgesics (Percocet, Darvocet) are effective in reducing the pain. The goal is to achieve adequate pain control while not oversedating the patient since shallow respirations and suppression of the cough reflex can lead to secretion retention, atelectasis (collapse of the alveoli) and possibly pneumonitis. With sufficient pain control, the patient should be encouraged to do deep breathing and coughing to keep the lung on the affected side functioning properly.
The greatest concern with a rib fracture is the high potential for damage to the underlying structures, mainly the lungs. If the sharp end of a fractured rib punctures the lung, it may collapse--a condition known as pneumothorax. The lung may only collapse a small portion or the entire affected side may go down. The patient condition can range from completely asymptomatic to marked respiratory distress. I have seen young, healthy patients with a totally collapsed lung in no distress at all and other, usually older patients, with a 20 percent pneumothorax and moderate to severe symptoms.
In addition to the signs and symptoms listed for the simple rib fracture, there are a few other findings that may lead you to suspect a collapsed lung. First, if there is a large enough pneumothorax, you may hear decreased or absent breath sounds on the affected side when you listen to the chest with a stethoscope. Tapping on the chest with your finger (percussion) will also reveal a drumlike sound when compared to the unaffected side. Keep in mind that the lung can be significantly collapsed and these two findings will be subtle at best. There may also be some subcutaneous emphysema of the chest wall. When air leaks out of the lung through a puncture, not only will the lung collapse, but the escaping air can find its way into the surrounding soft tissue. This subcutaneous air will feel like Rice Krispies under the skin when palpated and can extend over the entire chest area.
The management of a traumatic pneumothorax is beyond the scope of this forum. Suffice to say that a traumatic injury to the chest with associated symptoms of difficulty breathing, decreased breath sounds on the affected side and subcutaneous emphysema is reason for seeking immediate advanced medical care. It is best to keep the patient below, sitting upright on the lee side. This will make it the easiest for breathing while preventing further injury. Watch for signs of increasing distress such as coughing up blood, an increasing heart and respiratory rate and decreasing alertness. These can all be associated with a deteriorating condition.
As we mentioned, the definitive treatment of a collapsed lung exceeds the scope of the recreational sailor. Therefore, the most important task is to thoroughly evaluate a chest injury, have a high index of suspicion for a rib fracture given the mechanism of injury and maintain vigilance for deterioration of the patient's condition. Hopefully, this will be a problem you only read about here in FIRST AID.