You’re managing a 57-year-old male who presented after a fall from a 20-foot ladder. He landed hard on his right side. He is hypoxic to the high 80s, and he has diminished breath sounds on the right side but is otherwise stable. You complete your primary survey and obtain a chest x-ray. It reveals classic findings of a right-sided hemothorax. Your resident has already seen the film and has gowned up for the chest tube. As you look at his tray, you see a 36-French tube ready to go.
“Wait…I think we can go smaller.” Your resident, of course, looks at you with waning confidence, until you pull over the computer and show him some recent studies looking at just this topic.
That’s Not What We Were Taught!
The traditional teaching is just that – if you’re going to be draining blood, you need to be using a large size tube. Traditionally this has meant a 36- to 40-French open chest tube. The conventional thinking was that in order to effectively drain blood without clotting up the tube, you need one with a large diameter.
Inaba et al were amongst the first to challenge this. In a provocatively titled paper (“Does size matter?”), their group prospectively compared the traditional 36-40-French tubes (large) to 28-32-French (small) ones. Over three years they had about 275 chest tubes (144 small, 131 large) placed for hemothorax. The volume of blood drained initially and the total duration of tube placement were similar for both groups (small: 6.3 ± 3.9 days vs. large: 6.2 ± 3.6 days; adjusted (adj.) p = 0.427). In addition, they found no statistically significant difference in tube-related complications, including pneumonia (4.9% vs. 4.6%; adj. p = 0.282), empyema (4.2% vs. 4.6%; adj. p = 0.766), or retained hemothorax (11.8% vs. 10.7%; adj. p = 0.981). Although the groups were pretty similar, those getting larger tubes were more likely to be sicker (i.e.,hypotensive, unconscious, or with higher injury severity scores).
You might think 28-32-French is still pretty big, and you’d be right. So can we go smaller? Bauman et al looked at prospectively comparing 14-French pigtail catheters for hemothorax and pneumohemothorax as compared to the usual size chest tubes. Over 7 years, this group reviewed 496 patients (307 chest tube; 189 pigtail). They did note pigtails were used in older patients and placed on average a day later than standard chest tubes. However, they found no significant differences in tube-related complications or failure rates. In fact, they found the initial drainage volume was actually significantly higher in the pigtail group (425 mL [IQR 200-800 mL] vs. 300 mL [IQR 150-500], P < 0.001).
Want More Evidence?
A group of investigators out of the University of Arizona just published their multicenter randomized clinical trial (the P-CAT trial) in the Journal of Trauma and Acute Care Surgery. This group used block randomization to determine outcomes (primary outcomes: failure rate defined as retained hemothorax needed an additional procedure; secondary outcomes of daily drain output, number of tube days, ICU and hospital length of stay, and any attempt to define procedure tolerance using a 1-5 scale called the insertion perception experience score or IPE).
They studied patients over a five-year period. Inclusion criteria included adult patients (>18) with hemothorax or hemopneumothorax requiring drainage. Exclusion criteria included placement with patient in extremis, placement as part of an operative procedure, and refusal to participate.
Of 119 patients, 56 were randomized to the pigtail group. The primary outcome (failure rate) was similar between both groups (11% pigtail catheters vs. 13% chest tubes, P = 0.74). All secondary outcomes were similar, except that patients receiving the pigtail catheter were more likely to report a better perceived experience than those receiving a standard chest tube.
There are of course some caveats with this study. Overall, despite good methodology, only a small number were recruited. The authors cite some institutional challenges in physicians adopting pigtails as a viable alternative to chest tubes as one of the reasons for low recruitment numbers. The COVID pandemic also caused a premature closure of the study. Also, the scoring system for perceived experience was not one that has been validated elsewhere.
My Additional Thoughts
One caveat I would highlight also is that pigtails in several of these studies were placed in patients outside of emergent situations. Whether these results hold up in that situation is yet to be determined, although one can reasonably assume with the building evidence that it is likely going to be the same outcome.
- Most trauma patients with hemothorax do not require large chest tubes
- More emerging evidence supports the use of 14-French pigtail catheters as opposed to larger, traditional chest tubes
- The drainage rates and incidence of complications appear to be at least equal, and your patient may well thank you for using the smaller tube
- Inaba K, Lustenberger T, Recinos G, et al. Does size matter? A prospective analysis of 28-32 versus 36-40 French chest tube size in trauma. J Trauma Acute Care Surg. 2012 Feb;72(2):422-427. PMID: 22327984
- Bauman ZM, Kulvatunyou N, Joseph B, et al. A prospective study of 7-year experience using percutaneous 14-French pigtail catheters for traumatic hemothorax/hemopneumothorax at a Level-1 trauma center: size still does not matter. World J Surg 2018 Jan;42(1):107-113. PMID: 28795207
- Kulvatunyou N, Bauman ZM, Edine SBZ, et al. The small 14-French (Fr) percutaneous catheter vs. large (28-32Fr) open chest tube for traumatic hemothorax (P-CAT): a multicenter randomized clinical trial. J Trauma Acute Care Surg. March 16, 2021. Epub ahead of print. PMID: 33843831