Re-expansion pulmonary edema is an uncommon event after chest tube insertion. Typically, patients have had symptoms of pneumothorax for several days, usually 3 or more. It occurs most often if a large amount of air (or blood) is evacuated at once. The patient will typically become symptomatic within an hour, with decreased oxygen saturation and subjective breathing difficulty.
Although the mechanism is not entirely clear, it appears that the small blood vessels in the lung become more permeable if they are collapsed for an extended period. Mechanical stress from rapid re-expansion further damages the vessels, allowing them to leak. This leads to oxygenation and ventilation problems if severe.
- Check the history. Most of these patients have had their pneumothorax for 3 or more days.
- Check the xray. Complete pneumothorax (or large hemothorax) puts the patient at high risk.
- Modify your chest tube insertion technique. Clamp the distal end of the tube so the pneumothorax is not evacuated suddenly as the tube goes in.
- Modify the collection system. Do not use suction initially; only set up for water seal. Clamp the tubing on the patient side. Every 10-15 minutes release the clamp and briefly let some of the air out of the chest, then reclamp. Repeat this until all air has bubbled through the water seal chamber.
- Watch your patient. If they cough excessively, start to desaturate or become dyspneic, get your respiratory adjuncts. Give higher inspired oxygen by appropriate means, and consider BiPap or CPAP. In extreme cases intubation may be needed. If the patient does not have any difficulties after about an hour, connect the collection system to suction and proceed as you normally would.
Reference: Reexpansion pulmonary edema. Ann Thoracic Cardiovasc Surg 14:205-209, 2008.
Placing the chest tube collection system to water seal can be a valuable tool in determining if it’s time to remove the tube. The idea is that removing suction from the system will help identify a slow air leak that may not be obvious while watching the collection system. Typically, water seal without suction is maintained for 6 hours and a chest xray is obtained to look for a new (or larger) pneumothorax.
Here’s a way to detect a small air leak faster. When you enter the patient room, disconnect the suction tubing from the collection system. Chat with your patient, and do your usual thorough exam. Take your time. When you are done, slowly slip the suction tubing back onto the collection system. Watch the water seal chamber closely for any bubbles that try to sneak under the partition (above).
If the fluid level slowly lowers, but no bubbles pass the partition, there is no significant leak. On occasion, I’ve seen a single bubble creep under, and this is probably okay. However, if a train of bubbles passes, an air leak is present and it is premature to consider pulling the tube. Place the system back on suction.
Like so many tests, this one is only helpful if a leak is seen. It means that a significant amount of air has accumulated in the short time you’ve been examining your patient. If there are no bubbles, there still could be a very slow leak, so they will still need a formal water seal test, if indicated. See the protocol below for details.
So a young male jammed a handlebar into his abdomen, and a CT image demonstrating his problem was shown. But what did it actually show?
By now, you probably realize that clinical information is key. On exam, he had an obvious bulge in his left lower quadrant, more obvious with straining. Looking at the CT (now with a nice arrow), there is a problem over the left side of the abdomen.
This child has so little fat, that it’s difficult to see the problem. If you track the thin layer of fat across the abdomen to the right side of the image, you’ll see that it disappears over the bowel gas. This represents a complete tear through all fascial layers, not just a Spigelian hernia as some readers guessed.
Management consisted of primary repair of the defect. An uneventful recovery can be expected. Unless more bicycle tricks are anticipated.
Reference: Traumatic handlebar hernia: a rare abdominal wall hernia. J Ped Surg 39(10):e20-e22, 2004.
Yesterday’s puzzle involved a young male who drove a handlebar into his abdomen. Little additional information was given, other than one slice of his abdominal CT scan. So what’s the problem?
The textbooks always associate handlebars with pancreatic and duodenal injuries, and these should always be looked for. However, the scan slice in this case was taken lower, within the pelvis. Too low to show you either of those organs.
As I’ve said before, be systematic when reading xray images. We automatically focus on the viscera and bones. Look at those areas, make sure you can identify each structure that you see, and look for any anomalies.
But don’t forget the soft tissue! In this case, the child doesn’t have much. Take a closer look at the same slice and see if you can figure it out by tomorrow.
You figure it out. As usual, you get limited information up front.
An early teenage male was doing some crazy stuff with his bicycle. Unfortunately, he slipped, striking his abdomen on the handlebar.
Using this image alone, figure out the problem. Comment below or tweet your guesses! More tomorrow and Thursday.