Here’s a short video that shows you everything you need to know. Enjoy!
This short (10 minute) video demonstrated the technique for inserting small chest tubes, also known as “pigtail catheters.” It features Jessie Nelson MD from the Regions Hospital Department of Emergency Medicine. It was first shown at the third annual Trauma Education: The Next Education conference in September 2015, for which she was a course director.
Please feel free to leave any comments or ask any questions that you may have.
Yesterday I gave a little perspective on the use of CT in assessing the diaphragm after penetrating injury. Today, I’ll break it down into some practical steps you can follow the next time you see one.
Step 1. Stable or unstable? If your patient arrives with unstable vital signs, and there is no other source but the abdomen, the answer is simple. Go to the OR for a laparotomy. Period. They are exsanguinating and the hemorrhage needs to be stopped.
Step 2. Mark the sites of penetration and take a chest x-ray. This will let you evaluate the potential trajectory of the object, and will give you your first glimpse of the diaphragm.
Step 3. Examine the abdomen. Actually, you should be doing this at the same time you are setting up for Step 2. If your patient has peritoneal signs, no further evaluation is needed. Just go to the OR for laparotomy. Look at the chest x-ray once you get there.
Step 4. Right side? If your appreciation of the path of penetration involves just the liver, take the patient to CT for evaluation of chest, abdomen, and pelvis. You need to see all three of these areas to assess for blood and fluid in both body cavities. After the study, if you still think the injury is limited to the liver, admit the patient for observation.
Step 5. Left side? Look at that chest x-ray again. If there are any irregularities at all, strongly consider going to the OR and starting with diagnostic laparoscopy. These irregularities can be glaring, like in the x-ray above. But they can be subtle, like some haziness above the diaphragm or small hemothorax. Obviously, if the injury is as clear as on the x-ray above, just open the abdomen. But if in doubt, start small. And remember my advice on “lunchothorax.”
Step 6. Admit and observe. Check the abdomen periodically, and repeat the chest x-ray daily. If anything changes, consider diagnostic laparoscopy. As a general rule, I don’t keep patients NPO “just in case.” Most will pass this test, and I don’t see a reason to starve my patients for the low likelihood they need to go to the OR.
Step 7. Make sure your patient gets a follow up evaluation. See them in your outpatient clinic, get a final chest x-ray and abdominal exam before you completely clear them.
Penetrating injury to the diaphragm, and specifically stab wounds, have been notoriously hard to diagnose since just about forever. Way back in the day (before CT), we tried all kinds of interesting things to help figure out if the patient had a real injury. Of course, we could just go to the OR and lap the patient (laparoscopy did not exist then). But the negative lap rate was significant, so we tried a host of less invasive techniques.
Remember diagnostic peritoneal lavage? Yeah, we tried that. The problem was that the threshold for red cells per cubic mm was not well defined. Some would supplement this technique with a chest tube to see if lavage fluid would drain out. And one paper described instilling nuclear medicine tracer into the abdomen and sitting the patient under a gamma camera for a few hours to see if any ended up in the chest. Groan!
We thought that CT would save us. Unfortunately, resolution was terrible in the early years. If you could actually see the injury on CT, it was probably because a large piece of stomach or colon had already fallen through it. But as detectors multiplied and resolution improved, we could begin to see some smaller defects. But we still missed a few. And the problem is that left-sided diaphragmatic holes slowly enlarge over time (years), until the stomach or colon falls through it. (See below)
A group of radiologists and surgeons in a Turkish trauma hospital recently published a modest series of patients with left-sided diaphragm injuries evaluated by CT. They looked at about 5 years of their experience in a group of patient who were at risk for the injury due to a thoraco-abdominal stab wound. Unstable patients were immediately taken to OR. All of the remaining patients underwent an initial CT scan, followed by diagnostic laparoscopy after 48 hours if they remained symptom free.
Here are the factoids:
- A total of 43 stable patients with a left thoraco-abdominal stab were evaluated
- 30 patients had a normal CT, and 13 had the appearance of an injury
- Of those who were CT positive, only 9 of 13 (69%) actually had the injury at operation
- Two of the 30 (7%) who were CT negative were found to have a diaphragm injury during followup laparoscopy
- So in the author’s hands, there was 82% sensitivity, 88% specificity, a positive predictive value of only 69%, and a negative predictive value of 93%
Bottom line: The authors somehow looked at the numbers and concluded that CT is valuable for detecting left diaphragm injury. Huh? They missed 7% of injuries, only finding them later at laparoscopy. And they had a 31% negative laparotomy rate.
Now, it could be that the authors were using crappy equipment. Nowhere in their paper do they state how many detectors, or what technique was used. Since it took place over a 5 year period, it is quite possible that the earlier years of the study used equipment now considered to be out of date, or that there was no standardized technique.
CT may not yet be ready for prime time. But it can be a valuable tool. Tune in tomorrow for some tips on how and when to look for this insidious injury.
Reference: Evaluation of diaphragm in penetrating left thoracoabdominal
stab injuries: The role of multislice computed tomography. Injury 46:1734-1737, 2015.
I recently wrote about how the completion chest x-ray can lie after insertion of a chest tube. The chest x-ray image is a 2-D representation of the patient, but you really can’t tell where the tube lies in the third dimension (front to back). That’s how a trauma professional can get suckered into thinking they just put a perfect chest tube in, when in reality they have not.
How can you be sure of the position as you are putting it in? It’s a nuisance to have to reposition it after you’ve taken down your sterile field. Here are a few suggestions, but pay particular attention to the last one. I think it’s the best.
- Make the incision large enough so that you can visually confirm that the last hole is inside the thoracic cavity. This option is somewhat okay for thinner patients. But it leads to a larger than necessary incision, especially in patients who are obese. Not a great idea.
- Estimate proper depth before insertion. Hold the tube over the patient’s chest, and note the distance mark printed on the tube when the tip is placed halfway across the hemithorax (just medial to the nipple). This does take into account the amount of soft tissue on the lateral chest, but is not terribly accurate and you may accidentally contaminate the tube. The usual depth for a patient with normal body habitus is 12-14 cm at the skin. A better choice.
- Use the “bamboo flute” technique. Once you have entered the pleural space and placed the end of the tube into it, locate and place your finger firmly over the last hole, like you were playing a flute. Keep it there as you slide the tube in until your finger contacts the ribs around the insertion point. It should be at a right angle to the chest wall. Then push it in another 2-4 cm. As long as you have performed a nice dissection down to the chest wall, this technique is close to foolproof. And double-check by making sure that the tube is at least 12-14 cm at the skin. IMHO, this is the best technique.
This is not a chest tube!