Article:
Lyons NB, Abdelhamid MO, Collie BL, et al. Small versus large-bore thoracostomy for traumatic hemothorax: A systematic review and meta-analysis. J Trauma Acute Care Surg. 2024;97(4):631-638. doi:10.1097/TA.0000000000004412
Background and Results:
Tube thoracostomy is generally the recommended treatment for a traumatic hemothorax. However, there is no consensus on optimal catheter size. In recent years, there has been a move from using small bore tube thoracostomy (SBTT) for pneumothorax. SBTT provide increased patient comfort and seem to be equally as effective for pneumothorax. That said, what does the literature say about SBTT for hemothorax? Lyons et al. performed a systematic review and meta-analysis from inception up until November 2022 looking for randomized controlled trials or cohort studies that included adult trauma patients with hemothorax who received a tube thoracostomy. Their primary outcome was failure rate, defined as incompletely drained or retained hemothorax requiring a second intervention. They defined small bore as less than 14 French and large bore as over 20 French. Earlier research had shown that SBTT could possibly be effective in hemothorax, though more recent and robust literature has since been published that the authors wanted to review and include. Overall, there were 2,008 articles identified, with 11 ultimately included in the systematic review. Of the 11 included articles, there were three RCTs, three prospective cohort studies, and five retrospective cohort studies. Lyons et al. found that there was no significant difference between small and large bore tubes in failure rate, mortality, or overall complication rates. However, SBTT had a higher rate of insertion-related complications. They saw that SBTT required less VATS procedures, had better initial drainage, and fewer tube days.
Discussion:
It is interesting that SBTT had higher output than LBTT. The authors proposed that, because SBTT are often placed in a less emergent manner, it may give time for blood to collect, resulting in a higher output once inserted. Another proposed explanation was that SBTT are often placed under ultrasound guidance, allowing for more precise placement into the hemothorax. Further studies would be beneficial to assess large versus small bore tube efficacy when placed at the same time and to record and compare output.
Furthermore, the analysis showed no difference in the rate of overall mortality. However, patients who are more clinically stable are generally afforded more time to gain clinical information and potentially select a smaller tube size. In patients who are sicker, a trauma surgeon may resort to quickly placing a LBTT given that that is the classic teaching and the surgeon may want a quicker and more definitive fix in a crashing patient. Thus, the rates of mortality could be confounded by the fact that more stable patients may receive SBTT while sicker patients receive LBTT. Lastly, limitations include that only 3 of the studies were RCTs, and a few of the studies included patients with concomitant pneumothorax, which could have effects on outcomes.
Overall, it seems that SBTT may be as effective and recommended for patient's with traumatic hemothorax that do not require emergent chest tubes. However, in an emergent setting with patients in extremis, it may be prudent to select for a LBTT. Further work needs to be done to compare small versus large bore tube thoracostomy for hemothorax in trauma patients.
Expert Opinion for Trauma Surgery (Dr. Will Brigode):
Highly injured patients presenting in extremis are going to be more definitively managed at an earlier stage, so most emergency medicine and trauma surgeon physicians tend to use LBTT when clinical data is limited and there is limited understanding of a patient’s physiology. An old mantra that guided historical management of patients is that no blunt patient died without a tube in the trachea (intubation) and each chest (bilateral LBTT). With better access to ultrasound and portable x-ray, this is decreasing in prevalence but sometimes is necessary.
Despite the evolving literature that suggests SBTT are more well tolerated and possibly as effective as LBTT , many surgeons interpret the data differently, so I suspect many of these studies have significant selection bias. Table 1 supports these differences; some studies have differences in ISS (Injury Severity Score) and mechanism of trauma (SBTT more prevalent in blunt). Table 2 shows a marginal association with mortality in LBTT. While surgeons may have their opinions on chest tube size and efficacy, nobody would reasonably suspect that LBTT causes increased mortality, and the data support that sicker patients get LBTT.
One final confounder to this situation is best exemplified with a blunt trauma patient who presents with rib fractures. Not infrequently, patients present after a fall and sustain rib fractures, which are detected on CXR or CT. If there is no obvious hemopneumothorax on CXR or only a small (<2cm) hemothorax on CT (hemothorax size leading to chest tube selection is an entirely different clinical question), oftentimes these patient do not receive initial chest tubes of any type. Many patients are discharged with analgesia and no chest tube. A common progression of these patients is the development of a delayed hemothorax or rib fractures causing a pleural effusion based on inflammation of the pleura. Many of these patients develop fluid that is serosanguinous (bloody, but liquid). If it is liquid, the chest tube size does not particularly matter, as liquid is easily evacuated via a tube. This is different than an initial hemothorax that may have coagulated and is difficult to evacuate via any tube. Essentially, it’s easier to aspirate water through a straw than Jello. Many of these patients who present late have higher volumes but can be easily aspirated with a pigtail. This is based on experience but backed up by the statistical data they show where SBTT have higher initial volume than LBTT.
One final thing is the size within the distinction of small vs large. Within pigtails, I have a strong opinion that anything smaller than 14-16 is not useful. Many hospitals have “pericardial drains” that are 6-8 French in size that may decompress a pneumothorax, but I think are not appropriate for hemothorax or pleural effusion. They clog frequently even in just a pneumothorax so are fraught with failures. I recommend that if using a pigtail, use 14 French, which is commonly supplied in a “Wayne Pneumothorax Kit.” Regarding “large bore” chest tubes, there were prior recommendations to always use the biggest possible (36-40 French). There is data similar to what is presented here that shows no superiority of 36-40 French over 24-28 French. In addition, when you measure the intercostal distance on most humans (male or female) it does not accommodate 36-40 French tubes. If you measure the diameter, it is larger than the intercostal distance, so de facto will be collapsed into an ellipse which can cause kinking and occlusion. Therefore, in most patients there is no reason to go larger than a 28 French Tube.
Dr. Brigode’s overall practice:
“Medium Bore Chest Tube” (my term for something in the 20s, 28 French is my preferred 20-24 if 28 is unavailable):
Patient in extremis
Stable patient with a CXR showing obvious hemothorax
Stable patient with a large hemothorax on CT (>2-3cm): I worry about the coagulated blood clogging a pigtail
Small bore or 14 French Pigtail Catheter:
Stable patient with a delayed presentation and large pleural effusion that appears radiographically less consistent with coagulated blood and more consistent with effusion, or mixed density: trial of 14 French pigtail, counsel patients on possible need for re-intervention
Stable patient with isolated pneumothorax
Observation:
Stable patient with <1-2cm thick hemothorax
Authored by Kathryn McGregor, MD; Taylor Wahrenbrock, MD; Eric Leser, MD; and William Brigode, MD.