This is a sample of what a typical traumatic lecture page looks like. We've made it accessible so that you can get an idea of whether or not this format works for you. Take some time to read through the material. Videos help explain complex concepts; remember to turn your audio on.

Respiratory Distress & Arrest

This page focuses on understanding the pathophysiology, assessment, and treatment of traumatic injuries to the chest and respiratory system. The material on this page is summarized for field use in the Trauma section of the Wilderness Medicine Handbook.

Contents

Normal Anatomy & Physiology

Normal Anatomy & Physiology
The function of the respiratory system is to supply the blood with oxygen and remove carbon dioxide (carbon dioxide is acidic and its removal helps to maintain blood pH). Air enters and leaves the lungs via a set of air chambers (nasal and/or oral pharynx) and tubes (trachea, and bronchi). The lungs are a combination of air tubes (bronchi) and blood vessels that interface at tiny air sacks (alveoli) where the gas exchange takes place. The air tubes, blood vessels, and alveoli are held together by elastic connective tissue and surrounded by a resilient membrane called the visceral pleura. A second membrane, the parietal pleura, lines the interior of the chest cavity and is attached to the intercostal muscles and diaphragm. The parietal pleura is separated from the visceral pleura by a lubricating fluid. During respiration, the two are held together by the surface tension of the fluid.
Picture
Click to enlarge.
Breathing
Rising carbon dioxide levels stimulate chemoreceptors in the brain stem that signal the diaphragm and intercostal muscles to contract. Once triggered, the chest and lungs expand. As the intrathoracic space enlarges a negative pressure begins to build internally; and, in a process similar to that of expanding bellows, air is pulled into the lungs through the mouth or nose. The air passes through a series of smaller and smaller tubes (trachea, bronchi, bronchioles) until it fills microscopic air sacs (alveoli) and the pressure is equalized. The alveoli are enveloped by capillary beds and it is through the thin walls of the alveoli and the adjacent capillaries that the gas exchange takes place.

While inspiration is an active process, expiration is passive. During expiration the muscles relax, intrathoracic pressure increases, and air is expelled. Normal respirations are smooth, easy and quiet.

Respiratory Distress

Respiratory Distress
In addition to “knocking the wind out” of a patient, chest trauma may also break their ribs and/or damage their lung(s), making it difficult for them to breathe; penetrating chest trauma can directly damage the lungs. Medically, this is referred to as respiratory distress. If the patient’s lungs are severely damaged, the respiratory distress may progress to respiratory arrest.
Respiratory Distress S/Sx
  • Complains of difficulty breathing.
  • Cannot carry on a normal conversation without gasping for breath.
  • Assumes sitting or standing tripod position.
  • Attempts to sit up and often requires assistance.

Fractured Ribs

Fractured Ribs
If a rib is broken, the patient will report a stabbing knife-like pain each time they attempt to breathe and move their rib cage.  The pain will make it difficult for them to catch their breath and breathe easily until they learn to keep their chest quiet and breathe with their diaphragm (belly breathe). A broken rib becomes obvious as soon as the patient attempts to move or take a deep breath.

Lung damage is possible. A patient with multiple rib fractures has absorbed more kinetic energy from the blow and is in greater danger of developing lung damage than someone with an isolated rib fracture. Multiple ribs, each broken in two or more places (flail chest), may present with the broken section moving in opposite directions to the chest — in with inspiration and out with expiration — during respirations.

Lung Damage

Lung Damage
Lung damage and subsequent respiratory distress may result from bruised lung tissue or delamination of the pleura.

Pleural delamination—medically known as pneumothorax, hemothorax, hemopneumothorax or tension pneumothorax—results from air, blood, or a combination of air and blood leaking between the lining of the chest cavity (parietal pleura) and the lung stuff sack (visceral pleura) after one (or in extremely rare cases, both) pleura ruptures under the traumatic impact. A plerua delamination may also occur due to penetrating trauma (a knife, stick, ice axe, bullet, etc.).

If a patient’s pleura delaminates they will continue to have, or eventually develop, respiratory distress. If the damage to their lung(s) is severe enough, the patient will progress to respiratory arrest.
If the impact breaks the small capillaries that surround the alveoli, blood will leak into the tissue, causing a bruise that displaces air within the alveoli and respiratory distress. While lung bruises are rarely life threatening, they are impossible to distinguish from a lung delamination in the field.
Because a patient’s pulse increases proportionally with the severity of their respiratory distress, it is difficult—impossible without a blood pressure cuff—to rule out volume shock in the field.

Assessment & Treatment Summary

Basic Life Support Assessment & Treatment
Initial Patient Assessment
Upon arrival at the scene the patient is in respiratory distress and initially:
  • Complains of difficulty breathing.
  • Cannot carry on a normal conversation without gasping for breath.
  • Assumes sitting or standing tripod position.
  • Attempts to sit up and often requires assistance.
BLS Treatment
  • Reassure awake patients; if needed, assist them to a comfortable sitting position.
  • Maintain eye contact, coach patient to slow their respiratory rate and to belly breathe. 
  • Allow time for patient to calm down and for their respiratory rate to return to normal. 
Follow-up Assessment & Treatment
Assessment Summary
Trauma can temporally paralyze the diaphragm and intercostal muscles, making it difficult for the patient to catch their breath. If there is no physical damage, their breathing will return to normal within a few minutes.

If a rib is broken, the patient will report a stabbing knife-like pain each time they attempt to breathe and move their rib cage.  The pain will make it difficult for them to catch their breath and breathe easily until they learn to keep their chest quiet and breathe with their diaphragm (belly breathe). A broken rib becomes obvious as soon as the patient attempts to move or take a deep breath. Monitor for lung damage and internal bleeding.
Picture
Click image to enlarge
If the patient’s lungs have been been bruised or delaminated, they will continue to have difficulty breathing OR their breathing may appear to return to normal and they may develop respiratory distress gradually over the next few hours or days. Patient's with lung damage often complain of a "ball" in their lungs.

Lung delaminations due to penetrating trauma will become obvious during BLS or your physical exam.
Treatment Summary
If the patient presents with respiratory distress that resolves spontaneously within a few minutes, pain and tenderness are minimal, and the MOI is significant, monitor for potential lung damage and internal bleeding; consider a Level 3 Evacuation.

If the patient presents with the S/Sx of a broken rib and their initial respiratory distress resolves within a few minutes with belly breathing, begin a Level 3 Evacuation and monitor for potential lung damage and internal bleeding. Do NOT bind suspected rib fractures, instead, encourage the patient to take a deep breath every 20 minutes. This will help prevent a secondary pneumonia.

Immediately, cover open wounds associated with penetrating chest trauma and a lung delamination with an occlusive dressing and bandage; commercial chest seals with a one-way valve are preferred. (Remember to check for and cover both entrance and exit wounds.) You will need to "burp" dressings without a one-way valve if the patient's respiratory distress worsens: Lift the dressing briefly to allow the pressure to escape; you should see an immediate improvement in the patient's breathing.

If the patient's respiratory distress does not resolve on its own within a few minutes, does not resolve with belly breathing if a rib fracture is suspected, or if it reappears at any time:
  • Begin—or upgrade to—a Level 1 Evacuation.
  • DO NOT permit the patient to exercise.
  • Transport them in sitting position or on their injured side.
  • Assist their breathing with oxygen (if available).
  • CPR is NOT indicated if cardiac arrest is present.