SGEM#129: That Chest Tube…She’s a Beauty

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Date: August 14th, 2015

Guest Skeptic: Dr. Rick Malthaner is the Director of Thoracic Surgery Research, Professor of Surgery, Epidemiology and Biostatistics at the Schulich School of Medicine and Dentistry, Western University, Canada.

Case: A 25-year-old female was allegedly stabbed while standing on the corner minding her own business. She was found unconscious (Glasgow Coma Scale 7) and was intubated by the EMS. On arrival in your emergency department, the vitals are stable, but there is decreased air entry on the right side. You skillfully insert a right chest tube and get back 100 ml of blood. You review the post insertion chest tube x-ray and are somewhat disappointed by the position of your tube. It is hitting the mediastinum and curling back on itself and there is persistent white-out on the right.

Background: The “B” of the ABCs is really “Chest Tube”. Chest tubes didn’t become the standard of care for pneumothorax and hemothorax until the 1950s. The idea of draining the chest has been around since Hippocrates (460-370 B.C.) where he used tin tubes, linen, wine, and oil to drain empyemas.

The first mention of chest tubes for trauma was in the 1200s when a knight named Gawan used a tube of bark from a branch of a linden tree to treat a tension hemopneumothorax in another knight who sustained an injury during a joust.

Controversy existed over whether chest wounds should be left open or closed for the next few centuries. In the 17^th and 18^th century the importance of removing retained blood led to the practice of wound sucking. This was often done by the drummers of the military who sucked the wounds and then applied compresses and bandages.

During the wars of the last century there was debate over drainage systems versus repeated aspirations versus suture closure of open chest wounds. The mortality from chest wounds in World War I was 56%. Repeated chest thoracenteses was the treatment of choice for hemothorax and endorsed by NATO in 1958.

Plastic chest tubes were introduced in 1961 and closed thoracostomy and underwater seal drainage become common during the Vietnam War. The mortality rate dropped to 2.9%.

Current chest tubes are made from clear vinyl or silastic. They have multiple side holes and have centimeter markings to denote depth of insertion. A radiopaque strip allows visualization on chest x-ray. The principle of evacuation of pus, air, blood, and fluid from the pleural cavity that originated in ancient Greece remains the standard to this day.

Triangle of Safety: The triangle of safety is bordered by the anterior axillary line (pectoris major) and posterior axillary line (latissimus dorsi) and the 5^th intercostal space (roughly the level of the nipple in a thin male). The only muscles you need to go through are the serratus anterior and intercostals. The only structure of significance is the long thoracic nerve. If injured it will produce a winged scapula. This is rare. This the first choice for chest tube insertion in trauma.

Question#1: In a trauma patient, how clinically useful is a chest X-ray (CXR) after putting in the chest tube?

Reference: Kong et al. What is the yield of routine chest radiography following tube thoracostomy for trauma? Injury 2015

Population: Adults presenting or referred to a trauma centre who had a CXR after tube thoracostomy
- Group A: No CXR prior to tube insertion
- Group B: CXR prior to tube insertion with clinical concerns
- Group C: CXR prior to tube insertion without clinical concerns
- Excluded: Patients without complete data set
Intervention: CXR following tube thoracostomy
Comparison: None
Outcome: Yield of post CXR tube insertion influencing clinical management

Authors’ Conclusions: “Despite the widely accepted practice of routine CXR following tube thoracostomy, the yield is relatively low. In many cases, good clinical examination post tube insertion will provide warnings as to whether problems are likely to result. However, in the more rural setting, and in resource challenged environments, there is a relatively high yield from the CXR, which alters management.”

Quality Checklist for a Chart Review (Worster et al):

Were the abstractors trained before the data collection? Unsure
Were the inclusion and exclusion criteria for case selection defined? Yes
Were the variables defined? Yes
Did the abstractors use data abstraction forms? Unsure
Was the abstractors’ performance monitored? Unsure
Were the abstractors aware of the hypothesis/study objectives? Unsure
Was the interobserver reliability discussed? No
Was the interobserver reliability tested or measured? No
Was the medical record database identified or described? Yes
Was the method of sampling described? Yes
Was the statistical management of missing data described? Yes – they excluded any patients with missing data
Was the study approved by the institutional or ethics review board? Yes

Key Results:

N=1,004 patients (1,042 tube thoracostomies)
91% were male
Median age 24 years
75% penetrating trauma (3/4 from stab wounds)
- 33% Hemopneumothorax
- 30% Hemothorax
- 25% Pneumothorax
- 8% Tension pneumothorax
- 5% open pneumothorax

Group A: No initial CXR 103/1004 (10%)

¾ thought to be tension pneumothorax clinically and had needle decompression before tube thoracostomy
¼ thought to be simple pneumothorax clinically
Nine had their clinical management changed post CXR
- Five had kinked tubes that needed adjustment
- Four tubes were too shallow and needed new tubes

Group B: Initial CXR but clinically not well post tube thoracostomy 191/1004 (19%)

Clinical concerns included:
- 42% were outside the triangle of safety
- 39% tubes were not draining or swinging
- 10% still symptomatic
- 7% tube dislodged prior to post-CXR
- 1% blood post simple pneumothorax
- 1% gastric contents
111/191 (58%) post tube CXR had clinical management changed:
- 40% New Tube: 17% Subcutaneous, 16% tube was kinked and 7% non re-expansion of lung
- 14% Tube Adjusted: Tube not inserted far enough
- 4% Operating Room: 2% violated the diaphragm, 1% hemothorax post tube and 1% gastric cannulation
Specifically they mention 5 out of the 6 iatrogenic injuries had the tube thoracostomy done in a rural hospital and referred to the trauma centre

Group C: Initial CXR but no clinical concern post tube thoracostomy 710/1004 (71%)

32/710 (5%) had clinical management influenced post CXR
- 27/32 (84%) Tube was too deep
- 5/32 (16%) Tube on wrong side
- 4/5 Tube on wrong side were done in a rural hospital and referred to the trauma centre

It is always important to question dogma. ATLS has limited data to support its recommendation of routine CXR after tube thoracostomy. This study had a good objective of trying to shed some light on this area of trauma care.

Dr. Rick Malthaner

This study had a some limitations

Abstractors: We do not know much about the abstracting methods from reading the paper. However, Dr. Kong was contacted and he graciously provided more information. The data was collected prospectively and then retrospectively abstracted by one abstractor (Dr. Kong).
Exclusion: The problem of missing data is an interesting one. They just excluded all the patients whose data was not complete or missing a CXR. Dr. Kong reported via personal communication that only a few patients were ultimately excluded from the study due to missing data.
Referral Bias: They make reference to five out of six iatrogenic injuries who had their tube thoracostomies done in rural centres. Dr. Kong informed us that these were not emergency medicine physicians but rather a variety of physicians placing the chest tubes.
Small Numbers: The number of complications was low in this data set and was probably even lower than they reported. They reported 152 patients (15%) had their management impacted by the post procedure CXR. However, 59 patients just needed the tube adjusted. This leaves only 93/1,004 (9%) patients that really had their management changed. Group A had four patients who needed a new tube. Group B had 84 patients who needed a new tube (78) or were taken to the operating room (6). Group C had five patients who had the tube inserted on the wrong side.
- If the patient was doing well I would be tempted not to make an adjustment to the tube. If the tube is in the pleural space, it is working, i.e. fluctuating with respiration, draining and the lung is up, leave it alone. Repositioning a tube is rarely needed. Treat the patient not the CXR. The small numbers also impacts on their conclusions about rural tube thoracostomy. A retrospective chart review with only a handful of rural complications should be viewed with appropriate caution. However, placing the tube on the wrong side does seem like a significant error that should be avoided.
External Validity: This was a single trauma center study done in South Africa and the results may or may not be transferable to a North American health care environment. Although ATLS is a world wide training program, how well is it implemented in another country with a different health care system is not known?

Comment on Authors’ Conclusion Compared to SGEM Conclusion: We agree with the authors that the post tube thoracostomy CXR yield is too low to change management, but it is not zero. If the tube is draining and the patient is doing well the post CXR will probably not alter management.

SGEM Bottom Line: Put the tube on the correct side, within the triangle of safety, and within the pleural space. Continue to obtain a CXR post chest tube knowing it will probably not change management. Be more concerned if the patient is doing poorly or the tube is not draining.

Clinically Application: CXR post tube thoracostomy still seems like a reasonable test to continue to request.

Similar dogma has existed in trauma world about location of chest tube placement based on the injury pattern. The traditional teaching has been:

Pneumothorax – superior and anterior
Hemothorax – inferior and posterior
Avoid the Fissures

Question#2: Does chest tube location matter?

Reference: Benns et al. Does chest tube location matter? An analysis of chest tube position and the need for secondary interventions. J Trauma Acute Care Surg 2015

Population: All patients presenting to the emergency department requiring a chest tube with confirmed placement by CT scan
- Excluded: No CT scan, died early (<24hrs) or had thoracotomy (<24hrs)
Intervention: Location of chest tube (rib level and position of the tube relative to the lung parenchyma)
Comparison: None (observational trial)
Outcome: Duration of chest tube (clinical judgement: no air leak, radiographic resolution or <200ml drainage in 24hrs) and need for secondary intervention

Authors’ Conclusions: “Chest tube location does not influence the need for secondary interventions as long as the tube resides in the pleural space. The severity of chest injury is the most important factor influencing outcome in patients undergoing tube thoracostomy for trauma. Tube thoracostomy technique should focus on safe insertion within the pleural space and not on achieving a specific tube location.”

Quality Checklist for a Chart Review (Worster et al ):

Were the abstractors trained before the data collection? Unsure
Were the inclusion and exclusion criteria for case selection defined? Yes
Were the variables defined? Yes
Did the abstractors use data abstraction forms? Unsure
Was the abstractors’ performance monitored? Unsure
Were the abstractors aware of the hypothesis/study objectives? Unsure
Was the interobserver reliability discussed? Unsure
Was the interobserver reliability tested or measured? Unsure
Was the medical record database identified or described? Unsure
Was the method of sampling described? Yes
Was the statistical management of missing data described? No
Was the study approved by the institutional or ethics review board? Yes

Key Results: The data set consisted of 291 patients who had chest tubes placed in the emergency department with CT scans confirming position. There were 571 patients excluded because they died, had a thoracostomy or did not have a post tube CT scan. Most of the patients were male (81%) with a mean age of 40 years. Two-thirds of the patients had blunt trauma.

Duration of chest tube did not matter on location. Need for secondary intervention was also not associated with location.

Location did not matter.

A total of 48/291 (17%) of patients required secondary intervention. The most common thing needed was an additional chest tube (59%). Multivariate analysis demonstrated that AIS score, penetrating mechanism and initial chest tube output were significant risk factors.

This was another retrospectives study challenging some chest tube dogma about location, location, location. Some limitations include:

Retrospective: This type of study can only demonstrate association not causation.
Abstractors: Again we know very little about who these people were, how were they trained, how they performed and did they agree with each other.
Missing Data: Always important to know how researchers handle missing data. There is no perfect study and there is always some missing data. This can significantly influence the results of a study.
Selection Bias: Decision was based on clinical grounds or findings on portable CXRs. Perhaps patients with loculated fluid or air or less severe injuries (small pneuothoraces) would benefit with a chest tube directed to the anterior/superior location.
Exclusion Criteria: No CT scan, died early (<24hrs) or had thoracotomy (<24hrs). I understand if they do not have a CT scan they will not know exact tube placement. However, what I want to know is does location matter for patients who require a chest tube in the ER due to injury/trauma. It should be consecutive patients. We don’t really know if chest tube malposition may have contributed to death or the need for thoracotomy. Perhaps location did matter for those who die early or needed a thoracotomy. It would have been great to get confirm tube placement on all of those patients and compare it to all the patients who survived.

Comment on Authors’ Conclusion Compared to SGEM Conclusion: We generally agree that location does not appear to matter as long as you get the tube into the pleural space.

SGEM Bottom Line: Safely put the chest tube in the pleural space.

Case Resolution: The tube you placed appears to be fluctuating with breathing, has a small air leak, and continues to drain a small amount of blood. It appears to be working, so you leave it alone. Because of the persistent “white-out” you wonder if there may be something else going on such as a bronchial injury. You consult your friendly thoracic surgeon who confirms your suspicious with a bronchoscopy. The patient is taken to the operating room for repair and the patient recovers well. He informs you that your tube was in good position.

Clinical Application: Focus on getting the chest tube placed in the triangle of safety and try to place it superiorly and posteriorly, but don’t worry too much if it is not “perfect” on the post insert CXR. What matters most is if the patient is doing well post procedure.

What Do I Tell My Patient? In this case the patient was intubated so I would be speaking to her family. I would let them know she was stabbed in the chest that resulted in some internal bleeding and possibly a collapsed lung. The emergency department physician expertly put in a chest tube that drained out the blood. However, the CXR showed something else was going on. We therefore needed to take her to the operating room to repair an injury to the lung. This was done successfully and she is doing well. tube in the chest to drain fluid out of the chest. This resulted in blood in their chest a tube needed to be placed to drain the blood. The emergency physician expertly put in a chestThis did not work and she was taken to the operating room and we needed to put in a tube to drain the blood and re-expand the lung. WE NEED TO FIX THIS

Keener Kontest: Last weeks’ winner was Ilja Osthoff and anesthesiologist from Bavaria. Ilja knew Bill Finger is the un-credited second creator of Batman.

Listen to the podcast to hear this weeks’ keener question. If you know the answer email TheSGEM@gmail.com with keener/gunner in the subject line. The first person with the correct answer will receive a cool sceptical prize.