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Hyperresonnace is present in both tension and normal pneumothorax?

Discussion in 'Step I' started by str8flexed, 07.31.09.

  1. str8flexed

    str8flexed

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    Is this correct? If a pt has a tension pneumothorax, the lung is overinflated, and could be hyperresonant. Additionally, breathing is absent in this lung so there are decreased breath sounds.

    In a normal pneumothorax, the lung is collapsed, so I'm assuming the space between the lung and pleura causing hyperresonance?
  2. SimonSez

    SimonSez

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    The term Pneumothorax refers to a collection of air within the pleural cavity (i.e between the visceral and parietal pleural layers). This is therefore the case in BOTH Tension Pneumothorax and Simple Pneumothorax.The presence of this air in the pleural space is responsible for the hyperresonance found in both conditions. Also the fact that there is air interposed between the lung tissues and the chest wall (so to speak) there is also diminished breath sounds in both conditions.

    The difference between Tension and Simple Pneumothorax is that in Tension Pneumothorax the air is under tension (pressure) because the underlying cause is a "ball and valve" defect in the pleura (i.e: air can get into the pleural space but cannot leave). This is not the case in a Simple Pneumothorax as the nature of the defect in the pleura is such that air can both enter and leave the pleural space. Thus the air is not under pressure (tension) in a Simple Pneumothorax.

    The accumulation of air under pressure in a Tension Pnuemothorax leads to a shift of mediastinal structures to the contralateral side (i.e the side opposite the pneumothorax). Therefore an important clinical clue that points to a Tension Pneumothorax is DEVIATION OF THE TRACHEA to the contralateral side ( a finding NOT found in a Simple Pneumothorax). Of note: the shifting of the mediastinum can also cause kinking of the great vessels which leads to reduced cardiac output and HYPOTENSION (another possible feature of Tension but NOT Simple Pneumothorax).

    Hope this helps.
  3. Rendar5

    Rendar5

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    Something to note, and I'm not sure if you're tested on this in step 1 or step 2. Tension pneumothorax is a clinical diagnosis, not an X-Ray diagnosis, because of the immediate life-threatening behavior of this entity. You never order an X-ray for it; if you suspect it, you stick a needle in there.

    You would suspect this if the patient has decreased breath sounds and hyperresonance on one side, hypotension, tracheal shift to the opposite side, and jugular venous distension.
  4. braluk

    braluk SDN Surgerynator Moderator Emeritus

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    Just a clarification, is tension pneumothorax caused by a rupture of a subpleural lung bleb (particularly in smokers/atheletes?), while simple pneumothorax is caused by a penetrating knife wound into the pleural cavity?
  5. DeeJay2728

    DeeJay2728

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    I thought Tension Pneumothorax was the broad term used when describing this type of injury. There is always some sort of tension that causes diff breathing, TD, JVD, and a shift in the mediastinum... which are the tell tale signs to look for in tension hemo/pneumothorax. This type of injury is usually caused by some sort of sucking chest wound ie. gsw, stab wound, any type of puncture wound. Tx would be high conc O2, needle decompression, and (I don't know if they do this in the ED) making a flutter valve out of some sort of occlusive dressing with only three sides taped down allowing air to escape but not allowing anymore air in.
  6. Rendar5

    Rendar5

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    Deejay, you're confusing open pneumothorax with tesion pneumothorax. But what you said about each is correct. well, some of this is probably beyond step 1 and possibly 2, but if you guys are interested:

    Non-minor pneumothoraces and all hemothoraces are ultimately treated by chest tube insertion.

    pneumothorax this is just air in the pleural space regardless of the cuase. It comes in 2 flavors regardless of the cause: simple and tension. Tension is immediately life-threatening, simple is not. Tension is defined by mediastinal shift. All pneumothoraces have decreased breath sounds and hyperresonance because you're percussing directly over air. The difference between the two is clinical. Mediastinal shift occurs when air goes in and can't come out by a simple valve mechanism, such as the lung-side pleura being lacerated to form a flap-valve. Clinically, this shift is evidence first by hypotension and increased JVP and lastly by tracheal shift. If you see this, you put a needle in to allow air release and relieve the tension

    hemothorax this is just blood in the pleural space. It comes in 2 flavors: simple and massive. There is no tension form of this. Massive hemothorax is defined by volume of immediate blood return (>1500mL) on chest tube (or by volume of return over the course of an hour or so (forget this alternate definition). Massive is life-threatening, simple is not. Both get chest tubes, but one requires immediate surgical treatment.

    sucking chest wound/open pneumothorax this is a different entity, and occurs when there is a hole in the chest wall from some form of trauma. this hole is larger than 2/3 of the diameter of the trachea. Remember that air flows through the path of least resistance. If there is less resistance here than the trachea, when the diaphragm descends causing negative chest pressure, air flows into the pleural space here, instead of to the lungs through the trachea. This is treated by placing a piece of petroleum gauze on the wound, taping it down on 3 sides. This creates a flap-valve on the outside that lets air out of the pleural space, but won't let air in. Think of this as creating the opposite of a tension pneumothorax.

    EDIT: Everything done here is done in the ED either by the surgeons or the EP's. What would not be done in the ED is definitive repair down the line and surgical repair of a massive hemothorax.
  7. DeeJay2728

    DeeJay2728

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    Thank you for clarifying... But I'm still confused about one thing. Why wouldn't a hemothorax cause tension? Shouldn't anything in the plural space cause such an anatomical disturbance?

    Thanks again!!
  8. Rendar5

    Rendar5

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    Well, the short answer is that this doesn' t happen in real ife regardless of whatever reason. The longer answer is perhaps that there isn't enough blood in the body to create this pressure. Each side of the thoracic cavity can hold 2 liters of blood. When you hit that point, BP is already dropping drastically and you're in stage IV hemorrhagic shock (highest stage). You can pick whichever answer sounds better for you since i'm making them up. Either there isn't enough blood pressure at this point to push the mediastinum to the side. Or there's enough pressure within the pleural space from blood that it equalizes with the open major vessel that's causing the bleed. Or the third possible answer is that there is such an entity as tension hemothorax, but we don't see it because by the time this happens the person expires from exsanguination, so it is not a clinically important entity

    With tension pneumo, there's a relatively infinite amount of air that can keep going into the pleural space with each breath, and the negative pressure generated by the diaphragm is enough to overcome mediastinal pressure to not move.

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