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Old 03-30-2009, 17:39   #13
Pacer
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Join Date: Dec 2007
Location: Pennsylvania
Posts: 7
Quote:
Originally Posted by swatsurgeon View Post
An open wound BTW is a safe wound just like a 'simple' PTX....air exchanges and based on negative pressure ventilation (our usual method of breathing) vast majority of patients will do fine....if any problems, BVM or intubate and provide positive pressure ventilation then the open chest is a100% non-issue.
Controlling contamination is another but related issue.
ss

I'm going to go out on a limb here, and amplify/ expound just a little, as a NON THORACIC NON Surgeon.

I believe the concept of negative vs positive pressure ventilation is germane here. A physiology experiment/ analysis of formula, etc, suggest (note the language) that a chest wall defect that is continuously communicating (ie you can see lung or space) with a cross sectional area (Pi R squared) > 2/3 the same cross sectional area of the individals glottis will allow air to preferentially enter the chest wall (pleura) with NEGATIVE PRESSURE breathing (sucking, like all we humans do natively). While a simple Pneumothorax is often only mildly symptomatic in a sedate patient (dyspnea) and usually results in no hemodynamic effect other that hypoxemia (single lung ventilation, no time for physiologic compensation).

Note that many penetrating wounds (lo velocity, pistol or knife/ice pick) will self seal the chest wall as the tissue planes slide depending on the position of the arms, torso etc.

Just like a flail chest, where the chest wall segment compromises the negative thoracic pressure if large enough, POSITIVE PRESSURE VENTILATION (bag valve mask/intubation and ventilator) temporizes /treats the problem, but is less practical in a care under fire, mass casualty, disaster triage type environment (or cave rescue, mountain SAR without evac capacity).

A 'seal of choice" in the Hospital environment with adequate monitoring personnel is typically either to stuff it /over it with vaseline guaze, (later repair by the surgeon)

A tension pneumothorax (with very different hemodynamic consequences when the heart shifts and "crimps" the IVC/SVC) will only develop if gas can escape into the space (typically from the lung or bronchus) and cannot escape. Unfortunately, in high velocity GSW, explosive /IED,etc, or Hilar injuries, or under Blast overpressure/POSITIVE PRESSURE BREATHING, explosive decompression, etc, we are PROVIDING the pressure to faciliate such communication. Thats why we "prefer' to decompress "expectantly' in Fixed Wing Air Evac, (altitude and baro pressures are more severe than rotocraft, thought the problem can happen there to), and our surgical colleques may find SOME chests that require multiple garden hose chest tubes (36 Fr) to high suction to successfully re-inflate a lung (bronch-pulmonary fistula).

The easiest way, I agree SWAT Surgeon, is to release the seal and rethink the solution. Takes training and decisonal capacity, as well as being willing to spin the OODA loop and near continuosly monitor the individual patient (hard to do when the unit has another mission, and mulitple patients)

I "trained" as an Emergency Physician, in a knife and gun trauma center, after being a medic. If a tension pneumothorax requires decompression, what do you use if there is no external chest wound? recent Journal of trauma article challenges our "logic" and expediency, as a human study yield both inadequacies and complications from the "5 cm " (2 in) Jelco.

That's why the Trauma Surgeon (via ATLS) will usually dissect the tract for the chest tube, and stick a finger in there to make sure s/he is in the chest (and not the liver/stomach...) Air services might choose to use a "McSwain dart", though as a blind percutaneous "brutane" maneuver, has the same complications as the Jelco (IV Needle")

Just some thoughts.

Thanks for listening

B

Last edited by Pacer; 05-09-2009 at 19:22. Reason: typos
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