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Chest Tube Size Doesn’t Matter?

It’s great when you read a study that supports your own biases. But it’s not pleasant at all when you find one that refutes what you’ve been teaching for years. Well, I found one of those and I wanted to share it with you.

I’ve always said that there are only two sizes of chest tube for trauma, big (36Fr) and bigger (40Fr). Although there was no good literature, it seemed that a large tube would help ensure drainage of bigger clots if hemothorax was present.

A multicenter observational study was carried out that looked at 353 chest tube insertions. This work monitored retained hemothorax or pneumothorax, the need for tube reinsertion or invasive procedure due to incomplete drainage, and pain during insertion.

They had roughly 50:50 large (36-40Fr) vs small (28-32Fr) tubes. Tubes inserted for hemothorax were also 50:50 for large vs small. The initial amount of blood out was small and about the same for both groups. There was no significant difference in pneumonia, retained hemothorax, or empyema. The need for an invasive procedure (VATS or thoracotomy) was about 11% in both groups. Interestingly, there was no difference in visual analog pain score between the groups either.

Basically, large tube and small tube were the same.

Bottom line: Chest tube size selection probably doesn’t matter as much as we (I?) think. So it seems to make sense to select a tube size based on your patient’s chest wall, not dogma. Although subjective pain seems to be the same as well, pain and sedation management are key because this is not a fun procedure for the patient, regardless of tube size.

Reference: Does size matter? A prospective analysis of 28–32 versus 36–40 French chest tube size in trauma. J Trauma 72(2):422-427, 2012.

Pelvic Fractures: OR vs Angio In The Unstable Patient

One of the cardinal rules of trauma care is that hemodynamically unstable patients can only go the the operating room from the ED. No trips to CT, xray, etc. Trauma professionals occasionally try to make exceptions to the rule, but it usually doesn’t work out.

Well, what about the patient with severe pelvic fractures who is or becomes unstable? Pelvic fracture bleeding is not always easy or even possible to control in the OR, and angiography offers a way to identify and stop the bleeding, right?

The trauma group at Ryder in Miami did a lengthy (13 year) retrospective review of their experience with these patients. They looked at every patient who underwent angiography, then identified the subset that went to the OR followed by angiography. There were 134 angio patients and 49 OR to angio patients on whom they based their analysis. Obviously, there is plenty of opportunity for bias in this study, and many of the study patients identified had to be excluded due to incomplete records.

Patients who went to the OR first tended to have similar injury severity but were sicker than the angio alone group. Crystalloid and blood resuscitation volumes were significantly higher in the OR group as well. Most of these patients underwent a laparotomy, and 64% had active intra-abdominal bleeding. None died in OR, and most were left with a damage control abdominal closure.

In the angio group, there were really 2 subsets: angio alone, and angio followed by OR. Mortality in the angio alone group was similar to the OR-angio group. But deaths skyrocketed in those who went from angio to OR (67% vs 20%). This is likely due to them failing angiographic management of bleeding. Three patients died in the angio suite.

Bottom line: There’s a lot of data in this paper, and some of the results can be explained by selection bias. However, they appear to support algorithms released by EAST and the WTA (see diagram above). In general, a trauma patient with severe pelvic fractures and hemodynamic instability needs to go to OR to identify and treat any source of intra-abdominal bleeding. If pelvic bleeding remains a problem, preperitoneal packing may be considered, followed by a trip to angio at that point. The rule that unstable patients should only go to OR (or an ambulance bound for a trauma center if there is no OR) still holds!

Reference: Operating room or angiography suite for hemodynamically unstable pelvic fractures? J Trauma 72(2):364-372, 2012.

Quiz: There is just one extremely rare reason that I know of to move to CT with a hemodynamically unstable trauma patient. Leave a comment with your guess.

Central Line Insertion Causes Hypercoagulability?

Again, I’m not a fan of animal studies. But this one, presented at EAST 2012, involves both pigs and humans and is so intriguing I just have to share it. The authors have a track record of studying coagulation issues with thromboelastography (TEG) in both animals and people. They previously showed that hypercoagulability detectable by TEG occurs after insertion of pulmonary artery catheters in swine and critically ill humans.

In this follow-on study, they looked at TEG profiles in 16 healthy swine and 8 critically ill humans after insertion of a central venous catheter (CVC). They found that CVC insertion induced the same type of hypercoagulable state. TEG clotting time and initial clot formation time decreased, and fibrin cross-linking accelerated. The changes were somewhat less in humans, but were still significant in both groups. All coag tests (PT, PTT, INR) and measured coag factors (von Willebrand, AT III) were unchanged.

Interestingly, in the animal group the hypercoagulable state persisted for at least 3 hours after CVC removal. And the hypercoagulability could be prevented with enoxaparin, but not heparin.

Bottom line: The idea that hypercoagulability could be induced by central arterial or venous catheter placement is intriguing, although this work has not been replicated by others yet. What if hypercoagulability occurs with any invasion of the vascular system? We may eventually discover that the increased incidence of DVT we have been fighting in the hospital setting is in part due to our ubiquitous use of IVs and routine blood draws.

Reference: Insertion of central venous catheters induces a hypercoagulable state. Presented at the 25th Annual Scientific Assembly of EAST, Orlando FL, 2012.