Pulmonary contusion medical therapy

Overview
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No treatment is known to speed the healing of a pulmonary contusion; the main care is supportive. Attempts are made to discover injuries accompanying the contusion, to prevent additional injury, and to provide supportive care while waiting for the contusion to heal. Monitoring, including keeping track of fluid balance, respiratory function, and oxygen saturation using pulse oximetryis also required as the patient's condition may progressively worsen. Monitoring for complications such as pneumonia and acute respiratory distress syndrome is of critical importance. Treatment aims to prevent respiratory failure and to ensure adequate blood oxygenation. Supplemental oxygen can be given and it may be warmed and humidified. When the contusion does not respond to other treatments, extracorporeal membranous oxygenation may be used, pumping blood from the body into a machine that oxygenates it and removes carbon dioxide prior to pumping it back in.

Ventilation
Positive pressure ventilation, in which air is forced into the lungs, is needed when oxygenation is significantly impaired. Noninvasive positive pressure ventilation including continuous positive airway pressure (CPAP) and bi-level positive airway pressure (BiPAP), may be used to improve oxygenation and treat atelectasis. In both, air is blown into the airways at a prescribed pressure via a mask fitted tightly to the face; in BiPAP the pressure changes between inhalation and exhalation, while in CPAP the pressure is the same during both. Noninvasive ventilation has advantages over invasive methods because it does not carry the risk of infection that intubation does, and it allows normal coughing, swallowing, and speech. However, the technique may cause complications; it may force air into the stomach or cause aspiration of stomach contents, especially when level of consciousness is decreased.

People with signs of inadequate respiration or oxygenation may need to be intubated andmechanically ventilated. Mechanical ventilation aims to reduce pulmonary edema and increase oxygenation. Ventilation can reopen collapsed alveoli, but it is harmful for them to be repeatedly opened, and positive pressure ventilation can also damage the lung by overinflating it. Intubation is normally reserved for when respiratory problems occur, but most significant contusions do require intubation, and it may be done early in anticipation of this need. People with pulmonary contusion who are especially likely to need ventilation include those with prior severe lung disease or kidney problems; the elderly; those with a lowered level of consciousness; those with low blood oxygen or high carbon dioxide levels; and those who are going to be operated on and need anesthesia.

Pulmonary contusion or its complications such as acute respiratory distress syndrome may cause lungs to lose compliance (stiffen), so higher pressures may be needed to give normal amounts of air and oxygenate the blood adequately. Positive end-expiratory pressure (PEEP), which delivers air at a given pressure at the end of the expiratory cycle, can reduce edema and keep alveoli from collapsing. PEEP is considered necessary with mechanical ventilation; however, if the pressure is too great it can expand the size of the contusion and injure the lung. When the compliance of the injured lung differs significantly from that of the uninjured one, the lungs can be ventilated independently with two ventilators in order to deliver air at different pressures; this helps avoid injury from overinflation while providing adequate ventilation.

Fluid therapy
The administration of fluid therapy in individuals with pulmonary contusion is controversial. Excessive fluid in the circulatory system (hypervolemia) can worsen hypoxia because it can cause fluid leakage from injured capillaries (pulmonary edema), which are more permeable than normal. However, low blood volume (hypovolemia) resulting from insufficient fluid has an even worse impact, potentially causing hypovolemic shock; for people who have lost large amounts of blood, fluid resuscitation is necessary. A lot of the evidence supporting the idea that fluids should be withheld from people with pulmonary contusion came from animal studies, not clinical trials with humans; human studies have had conflicting findings on whether fluid resuscitation worsens the condition. For people who do require large amounts of intravenous fluid, a catheter may be placed in the pulmonary artery to measure the pressure within it. Measuring pulmonary artery pressure allows the clinician to give enough fluids to prevent shock without exacerbating edema. Diuretics, drugs that increase urine output to reduce excessive fluid in the system, can be used when fluid overload does occur. Furosemide, a diuretic used in the treatment of pulmonary contusion, also relaxes the smooth muscle in the veins of the lungs, thereby decreasing pulmonary venous resistance and reducing the pressure in the pulmonary capillaries.

Supportive care
Retaining secretions in the airways can worsen hypoxia and lead to infections. Thus, an important part of treatment is pulmonary toilet, the use of suction, deep breathing, coughing, and other methods to remove material such as mucus and blood from the airways. Chest physical therapy makes use of techniques such as breathing exercises, stimulation of coughing, suctioning, percussion, movement, vibration, and drainage to rid the lungs of secretions, increase oxygenation, and expand collapsed parts of the lungs. People with pulmonary contusion, especially those who do not respond well to other treatments, may be positioned with the uninjured lung lower than the injured one to improve oxygenation. Inadequate pulmonary toilet can result in pneumonia. People who do develop infections are given antibiotics. No studies have yet shown a benefit of using antibiotics as a preventative measure before infection occurs, although some doctors do recommend prophylactic antibiotic use even without scientific evidence of its benefit. However, this can cause the development ofantibiotic resistant strains of bacteria, so giving antibiotics without a clear need is normally discouraged. For people who are at especially high risk of developing infections, the sputum can be cultured to test for the presence of infection-causing bacteria; when they are present, antibiotics are used.

Pain control is another means to facilitate the elimination of secretions. A chest wall injury can make coughing painful, increasing the likelihood that secretions will accumulate in the airways. Chest injuries also contribute to hypoventilation (inadequate breathing) because the chest wall movement involved in breathing adequately is painful. Insufficient expansion of the chest may lead to atelectasis, further reducing oxygenation of the blood. Analgesics (pain medications) can be given to reduce pain. Injection of anesthetics into nerves in the chest wall, called nerve blockade, is another approach to pain management; this does not depress respiration the way some pain medications can.