Tag Archives: tension pneumothorax

Flying Or Diving After Traumatic Pneumothorax

Patients who have sustained a traumatic pneumothorax occasionally ask how soon they can fly in an airplane or scuba dive after they are discharged. What’s the right answer?

The basic problem has to do with Boyle’s Law (remember that from high school?). The volume of a gas varies inversely with the barometric pressure. So the lower the pressure, the larger a volume of gas becomes. Most of us hang out pretty close to sea level, so this is not an issue. But for flyers or divers, it may be.

Flying

Helicopters typically fly only one to two thousand feet above the ground, so the air pressure is about the same as standing on the earth. However, flying in a commercial airliner is different. Even though the aircraft may cruise at 30,000+ feet, the inside of the cabin remains considerably lower though not at sea level. Typically, the cabin altitude goes up to about 8,000 to 9,000 feet. Using Boyle’s law, any volume of gas (say, a pneumothorax in your chest), will increase by about a third on a commercial flight.

The physiologic effect of this increase depends upon the patient. If they are young and fit, they may never know anything is happening. But if they are elderly and/or have a limited pulmonary reserve, it may compromise enough lung function to make them symptomatic. And having a medical problem in an aluminum tube at 30,000 feet is never good.

Commercial guidelines for travel after pneumothorax range from 2-6 weeks. The Aerospace Medical Association published guidelines that state that 2-3 weeks is acceptable. The Orlando Regional Medical Center reviewed the literature and devised a practice guideline that has a single Level 2 recommendation that commercial air travel is safe 2 weeks after resolution of the pneumothorax, and that a chest x-ray should be obtained immediately prior to travel to confirm resolution.

Diving

Diving would seem to be pretty safe, right? Any pneumothorax would just shrink while the diver was at depth, then re-expand to the original size when he or she surfaces, right?

Not so fast. You are forgetting why the pneumothorax was there in the first place. The lung was injured, most likely via tearing it, penetration by something sharp, or popping a bleb. If the injured area has not completely healed, then air may begin to escape through it again. And since the air used in scuba diving is delivered under pressure, this could result in a tension pneumothorax.  This is disastrous underwater!

Most injuries leading to pneumothorax heal completely. However, if there are bone spicules stuck in the lung or more complicated parenchymal injuries from penetrating injury, they may never completely heal. This makes the diver susceptible to a tension pneumothorax anytime they use their regulator.

Bottom line: Most patients can safely travel on commercial aircraft 2 weeks after resolution of pneumothorax. Ideally, a chest xray should be obtained shortly before travel to confirm that it is gone. Helicopter travel is okay at any time, since they typically fly at 1,500 feet or less.

Divers should see a physician trained in dive medicine to evaluate their injury and imaging prior to making another dive.

References:

  • Divers Alert Network – Pneumothorax – click to download
  • Practice Guideline, Orlando Regional Medical Center. Air travel following traumatic pneumothorax. October 2009.
  • Medical Guidelines for Airline Travel, 2nd edition. Aerospace Medical Association. Aviation, Space, and Environmental Medicine 74(5) Section II Supplement, May 2003.

Advanced Needle Thoracostomy

In the past, I’ve written about the merits of needle vs finger thoracostomy. One of the arguments against needle thoracostomy is that it may not reach into the chest cavity in obese patients. As I mentioned yesterday, use the right needle!

Obviously, the one on top isn’t going to get you very far. The bottom one (10 gauge 3 inch) should get into most pleural spaces.

But what if you don’t have the right needle? Or what if the patient is massively obese and the longer needle won’t even reach? Pushing harder may seem logical, but it doesn’t work. You might be able to get the needle to reach to the pleural space, but the catheter won’t stay in it.

Here’s the trick. First, make the angiocatheter longer by hooking it up to a small (5 or 10cc) syringe. Now prep the chest over your location of choice (2nd intercostal space, mid-clavicular line or 5th intercostal space, anterior axillary line) and make a skin incision slightly larger than the diameter of the syringe. Now place the syringe and attached needle into the chest via your incision. It is guaranteed to reach the pleura, because you can now get the hub of the catheter down to the level of the ribs. Just don’t forget to pull out the catheter once you’ve placed the chest tube!

Related posts:

The Right Way to Treat Tension Pneumothorax

Tension pneumothorax is an uncommon but potentially lethal manifestation of chest injury. An injury to the lung occurs that creates a one-way valve effect, allowing a small amount of air to escape with every breath. Eventually the volume becomes so large as to cause the lung and mediastinum to push toward the other side, with profound hypotension and cardiovascular collapse.

The classic clinical findings are:

  • Hypotension
  • Decreased or absent breath sounds on the affected side
  • Hyperresonance to percussion
  • Shift of the trachea away from the affected side
  • Distended neck veins

You should never diagnose a tension pneumothorax with a chest xray or CT scan, because the diagnosis is a clinical one and the patient may die while these procedures are carried out. Having said that, here’s one:

image

The arrow points to the completely collapsed lung. Note the trachea bowing to the right.

As soon as the diagnosis is made, the right thing to do is to “needle the chest.” A large bore angiocath should be placed in the second intercostal space, mid-clavicular line, sliding right over the top of the third rib. The needle should then be removed, leaving the catheter.

The traditional large bore needle is 14 gauge, but they tend to be short and flimsy. They may not penetrate the pleura in an obese patient, and will probably kink off rapidly. Order the largest, longest angiocath possible and stock them in your trauma resuscitation rooms.

image

The top catheter in this photo is a 14 gauge 1.25 inch model. The bottom (preferred at Regions) is a 10 gauge 3 inch unit. Big difference! 

The final tip to treating a tension pneumothorax is that a chest tube must be placed immediately after inserting the needle. If the patient is on a ventilator, the positive pressure will slowly expand the lung. But if they are breathing spontaneously, the needle will change the tension pneumothorax into a simple open pneumothorax. Patients with other cardiovascular problems will not tolerate this for long and may need to be intubated if you dawdle.

Related post:

Another Way To Treat Tension Pneumothorax

Kenji Inaba and colleagues have done a lot of work on tension pneumothorax (tPTX) in the past few years. They’ve looked for the best devices and the best positions on the chest to quickly and effectively treat this emergency. Now, they’ve published a study on using what looks like a “better mousetrap” for relieving tension physiology.

Previous work from this lab has shown that up to a quarter of needle thoracostomies fail within 5 minutes due to mechanical reasons. This leaves a small window for insertion of the real chest tube. And even though much of the pressure may be relieved, a significant amount of air may be left in the chest, impeding recovery from PEA arrest.

They looked at the use of a 5mm laparoscopy port for relief of tension pneumothorax in Yorkshire swine. The exact size of the pigs was not listed, but these animals weigh 25 pounds at 6 weeks of age, and the pictures in the article show a reasonable sized animal. I’m not sure they were 70kg, though.

Here are the factoids:

  • Five animals were used, and 30 episodes of tPTX and 27 episodes of PEA arrest from tPTX
  • Tension pneumothorax was created by insufflating the chest with CO2 using a 10mm laparoscopic trocar
  • tPTX was completely relieved by insertion of the 5mm trocar in 100% of trials, with all physiologic measures returning to baseline within 1 minute
  • Circulation was restored to normal within 30 seconds in 100% of trials
  • There was no damage to heart or lung from trocar placement in any of the 5 animals

image

Bottom line: Once again, Inaba and crew have added some interesting tidbits to our knowledge base. You already know I’m not a fan of animal studies like this, but this one lays the ground work for some work in humans. We still need to know how the “usual American body habitus” will affect the use of this device. The only downside is the expense of the trocar, which is a lot more than a simple long needle. But if it is as efficacious in humans as it is in pigs, it may be worth it!

Related posts:

Reference: Standard laparoscopic trocars for the treatment of tension pneumothorax: A superior alternative to needle decompression. J Trauma 77(1):170-175, 2014.