Ventilation:

Mechanical ventilation may be required if pulmonary contusion causes inadequate oxygenation.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 and mechanically 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.
Commotio cordis:Commotio cordis is a sudden disturbance of heart rhythm observed mostly in boys and young men during participation in sports. Commotio cordis is Latin for "commotion of the heart": the term refers to a functional effect of mechanical stimulation in the absence of structural damage, as opposed to myocardial contusion which involves tissue damage.

It occurs as the result of a blunt, non-penetrating impact to the precordial region, often caused by impact of a ball, a bat or other projectile. The impact is transmitted to the heart muscle, and depending on the precise timing in relation to the cardiac cycle, it may affect the heart's electrical activity, causing an arrhythmia, such as an ectopic beat, ventricular tachycardia or ventricular fibrillation.

Pre-existing conditions, such as undetected electrical or structural abnormalities in the heart of these individuals, have been speculated to render individuals more vulnerable, but this view is not currently corroborated by hard evidence. The phenomenon was confirmed experimentally in the 1930s, with research in anaesthetized rabbits, cats and dogs.