Time Stamps

• 02:50 X-ray vs. POCUS vs. CT for pneumothorax diagnosis
• 07:29 Do all pneumothorax need chest tubes?
• 11:55 Explaining pneumothorax to patients
• 14:58 Understanding the pleural drainage system
• 26:11 Monitoring air leaks with the water seal chamber
• 32:27 Managing persistent air leaks

Show Notes

Pearl 1: Diagnosis of Pneumothorax

A pneumothorax is defined as a collection of air within the pleural cavity, between the lung and chest wall.

• There are two main subtypes of pneumothorax:
  • Primary spontaneous pneumothorax: occurs in the absence of underlying lung disease
    • Commonly in tall, thin, young males
  • Secondary spontaneous pneumothorax: occurs in the presence of underlying lung disease
    • Most commonly in the setting of bullous emphysema
    • Other, less common underlying lung diseases include cystic fibrosis, interstitial lung disease, and cystic lung diseases (such as lymphangioleiomyomatosis (LAM))

Chest X-Ray:

• Easy, fast, and available: frequently first-line and initial modality
• Pooled sensitivity 52%, specificity 100% per 2011 meta-analysis (Ding et al.)
• Upright chest X-ray is preferred – more sensitive and more likely to detect small pneumothoraces as compared to supine imaging.
• The deep sulcus sign (sharp, angular lucency of lateral costophrenic angle that extends inferiorly) can be indicative of pneumothorax on supine chest X-ray.
• Other X-ray signs of pneumothorax include tracheal deviation away from affected side, as well as mediastinal shift (especially in case of tension pneumothorax).

Ultrasound:

• Most sensitive (88%) and specific (99%) modality
• Ability to use at point-of-care
• User-dependent for obtaining and interpreting images
• Absence of lung sliding (movement between pleura and chest wall) is diagnostic of pneumothorax
• Identification of the lung point – the transition point between absence and presence of lung-sliding – is a highly specific sign (nearly 100%) for diagnosis of pneumothorax
  • Note: lung sliding may not be present if the pleural surface is disrupted – in patients who have previously undergone pleurodesis or with severe bullous emphysema, lack of lung sliding may be present without pneumothorax
• Using M-mode can be useful to detect lung sliding:
  • Normal, sliding lung will display the sshore sign, indicative of pleural movement with respiration
  • Pneumothorax (and absence of lung sliding) will display the barcode sign, notable for parallel hypoechoic lines without the movement seen in normal tidaling.

CT Chest:

• Gold standard imaging, with ability to determine pneumothorax size, loculations, and underlying parenchymal disease
• Most useful in patients with underlying parenchymal lung disease
• Pearl: In patients with COPD, large bullae can sometimes be mistaken for pneumothorax on chest X-ray or via ultrasound! CT chest can help determine presence or absence of a pneumothorax along with a more detailed assessment of localization and size prior to proceduralization.

Pearl 2: Initial Pneumothorax Management

• Pleuritic chest pain, dyspnea, chest tightness

Signs

• Hypoxemia, tachypnea, tachycardia, unilaterally diminished breath sounds
• Subcutaneous emphysema is a worrisome clinical finding, especially around the neck or upper torso.
  • This can result in dysphagia, dysphonia, and airway compromise!

Tension Pneumothorax

• Results from one-way airflow into the pleural space without outflow, causing compression of structures in the thorax (heart, inferior vena cava)
• Clinically, presents with hypotension, distended neck veins, and tachycardia
• Treatment: emergent needle decompression or chest tube placement
  • Typically performed via angiocath insertion with either an anterior approach (2nd intercostal space at midclavicular line) or lateral approach (5th intercostal space at midaxillary line)
  • If supplies are readily available, emergent chest tube placement is a more durable intervention for tension pneumothorax.

Intervention vs. Monitoring

• Conservative management can be a safe alternative to interventional strategies.
  • Current guidelines from both the European Respiratory Society and British Thoracic Society recommend conservative management for asymptomatic pneumothorax.
  • A 2020 randomized controlled trial published in the New England Journal of Medicine showed conservative management of primary spontaneous pneumothorax is noninferior to interventional management.
    • Open-label, multicenter trial which compared intervention vs. conservative management in moderate-to-large primary spontaneous pneumothorax
• For symptomatic pneumothorax without tension physiology, chest tube placement (tube thoracostomy) is likely indicated.
  • • Practice patterns may vary. Some evidence for no chest tubes in patients with mild to moderate symptoms (see study in Australia).
  • Typically performed via Seldinger technique, often at the bedside.
  • Small bore chest tubes (i.e. pigtails) are generally preferred for pneumothorax, and have been shown to result in fewer complications and less pain as compared to large bore tube placement.

Pearl 3: Understanding the Pleural Drainage System

Once a chest tube is placed, the pleural drainage system ensures patient safety and allows for accurate, real-time monitoring of chest tube output (whether air or fluid).

• Chamber 1: Collection
  • The first chamber is used to quantify fluid draining from the tube – usually in cases of pleural effusion or hemothorax.
• Chamber 2: Water seal
  • This chamber allows outflow of air into a chamber of water, preventing air inflow into the chest, ensuring patient safety.
  • Bubbling in this chamber indicates an air leak.
    • The degree of air leak can serve as a peek inside the pleural space – giving crucial information as to how the pneumothorax is resolving or progressing.
• Chamber 3: Suction
  • The pleural drainage system can be attached to wall suction to increase negative pressure and help promote outflow of air or fluid.
  • This chamber allows for titration and monitoring of the degree of suction applied (typically from -10mmHg to -40mmHg).
  • Typically, an indicator in this chamber is inflated when suction is applied.
  • Pop-off valves open and close to the outside environment to help maintain a consistent pressure.

How does this play into pneumothorax management?

• Suction is often applied to help expedite air removal from the pneumothorax.
  • As more air is evacuated from the pneumothorax, the lung can slowly begin to reexpand.
  • Once fully expanded (and visceral and parietal pleural surfaces are in contact), the pleural defect can begin to heal.
  • However, suction can be a double-edged sword – too much can propagate air outflow from the pleural defect, worsening the pneumothorax.
  • Careful adjustment of suction with frequent monitoring after changes is key!
• Once less suction is required, water seal is the next step.
  • Here, there is no suction adding negative pressure to drive air out of the pneumothorax.
  • Once the air leak has completely resolved, a clamp trial can be considered.

Pearl 4: Air Leak Monitoring

As above, the water seal chamber allows for visualization of air leak, an important diagnostic tool in pneumothorax management.

• Air leak is visualized as bubbling within the water seal chamber.
• This is indicative of air moving from the pleural space into the tube, meaning pneumothorax is still present.
• Air leaks can be quantified easily using the Cerfolio Classification, which grades air leak severity on a scale of I (during forced expiration only) to IV (continuous air leak).
• Observing change in air leak during various parts of the respiratory cycle or with dynamic maneuvers (i.e. deep breathing, coughing, Valsalva) can give helpful information regarding air leak severity!

Tip: Always ensure there is enough water placed inside the chamber itself! If the tube is not submerged beneath a level of water, the one-way function of the chamber will not work and air could flow back into the pleural space.

Tidaling is the visible change in intrathoracic pressure during a normal respiratory cycle, distinct from air leak.

• This can be seen in pleural fluid within the tube itself, or via an indicator ball on the pleural drainage system (typically near the water seal chamber).
• Normally, this will present as fluid moving in (or ball moving up) with inspiration, and out (or down) with expiration.
• Loss of tidaling indicates some disruption in the chest tube itself, like kinking or displacement.

After progression from suction to water seal and resolution of the air leak, clamp trialing is the last step prior to chest tube removal.

Clamp trialing simulates if the chest tube were to be removed.

• This can be dangerous! Development of symptoms can indicate reaccumulation of the pneumothorax, which can continue to progress if the tube is not unclamped.
• Communication with the patient and all relevant members of the medical team about this is key – patients can feel empowered to unclamp their own chest tubes if symptoms like dyspnea or chest pain develop.
• If a clamp trial is successful and following up imaging shows no reaccumulation of pneumothorax, chest tube removal can be considered.

Pearl 5: Persistent Air Leak

• Air leaks are defined as persistent after 5 days.

Options to resolve a persistent air leak include:

• Autologous blood patch:
  • This technique involves instilling a small amount of a patient’s own blood (50-100mL) into the pleural space.
  • Resulting inflammatory and clotting response results in repair of the pleural defect with resolution of the air leak.
  • Adequate evidence basis:
    • 2010 review reported up to 93% success rate in patients with persistent air leak following pulmonary resection or spontaneous pneumothorax
    • Two small randomized controlled trials have also demonstrated this technique is effective (Ibrahim et al 2018; Cao et al 2012)
  • Risks include infection (empyema) and clot obstructing chest tube outflow – care must be taken to ensure a sterile environment during initial blood draw and instillation.
• Endobronchial valves:
  • One-way valves placed via bronchoscope to limit air inflow to and promote air outflow from affected areas of the lung.
  • Case series have shown this to be an effective strategy.
  • Risks include pneumothorax, infection (pneumonia), and valve migration after placement.
• Pleurodesis:
  • Instillation of chemicals or medications that cause inflammation, seal the pleural space, and prevent pneumothorax recurrence.
  • Common agents include talc and doxycycline.
  • Risks include pneumothorax, infection, fever (secondary to inflammatory response).
  • Pearl: This can make subsequent thoracic surgery more challenging – use with caution in patients who may be candidates for lung transplant in the future.

Transcript

Dr. Mihir Parikh: It’s an important topic to go over just because the three chamber system I refer to as the black box, even though it’s a white box, but it feels like a black box because people come into it, take a look at it, they’re not really sure what they’re supposed to be looking at, but they look at it anyway and then they walk out of the room. And so I think it’s important to kind of decipher the black box a little bit.

Dr. Shreya Trivedi: That’s Dr. Mihir Parikh, an Interventional Pulmonologist at BIDMC. Welcome to the CORE IM 5 Pearls Podcast, bringing you high-yield, evidence-based pearls. I’m Dr. Sherya Trivedi.

Dr. Alexander Castro: And I’m Dr. Alexander Castro, an internal medicine resident at BIDMC.

Dr. Shreya Trivedi: Today we’re talking all things about Pneumothorax. All right, let’s get into it. Test yourself by pausing after these questions. And remember, the more you test yourself, the deeper your learning gains.

Dr. Alexander Castro: Pearl 1: Diagnosis of Pneumothorax

Dr. Shreya Trivedi: Which imaging modality is the best for diagnosis? And what types of pneumothorax are important to recognize?

Dr. Alexander Castro: Pearl 2: Initial Pneumothorax Management

Dr. Shreya Trivedi: Who gets a chest tube and who can be conservatively managed?

Dr. Alexander Castro: Pearl 3: Understanding the Pleural Drainage System

Dr. Shreya Trivedi: Do you have a step-by-step approach of looking through a pleural drainage system?+

Dr. Alexander Castro: Pearl 4: Air Leak Monitoring

Dr. Shreya Trivedi: What is an air leak and how do you know how bad it is?

Dr. Alexander Castro: Pearl 5: Persistent Air Leak

Dr. Shreya Trivedi: When we diagnose an air leak as persistent, what are the options that we can use to treat it?

Pearl 1: Diagnosis of Pneumothorax

Dr. Shreya Trivedi: So before we get into imaging pearls in diagnosis a pneumothorax. Let’s start with – what exactly is a pneumothorax?

Dr. Mihir Parikh: Yeah. And so what I do tell patients is that the way I explain to them is that there’s been some injury to the lining of the lung and that has led air to escape from the lung into the space between the lung and the chest wall.

Dr. Alexander Castro: So Dr. Parikh describes pneumothorax as air that escapes from the lung and accumulates between the lung and chest wall, or more formally, for us, the visceral and parietal pleura – outside the lung, but within the pleural cavity. And these are split into two main categories: primary and secondary.

Dr. Mihir Parikh: So the spontaneous pneumothorax is sort of that the run of the mill patient walking down the street all of a sudden develops chest pain and develops a pneumothorax, and that is subdivided into two groups. So this primary spontaneous pneumothorax and secondary spontaneous pneumothorax. So primary spontaneous pneumothorax means that they don’t have any underlying lung disease, whereas secondary spontaneous pneumothorax, it means that they have some underlying lung disease that we think predisposed them to developing spontaneous pneumothorax. Most commonly that’s severe COPD emphysema. But other things can be like cystic lung disease.

Dr. Shreya Trivedi: So primary spontaneous pneumothorax that’s going to occur without underlying lung disease. And then secondary spontaneous pneumothorax, that’s going to be usually in the setting of some underlying lung disease. And hold onto that idea because understanding the underlying lung parenchyma is going to be important in thinking about what’s the best imaging modality for diagnosing pneumothorax.

Dr. Alexander Castro: I think that by far the most common way I’ve seen pneumothorax diagnosed is via chest x-rays. But I was surprised to learn how much positioning matters in making the diagnosis.

Dr. Mihir Parikh: And the point I like to make with plain films is that the sensitivity of a plain film, like a chest X-ray, goes up a lot when you put them into the correct position. So air rises with gravity, right? And so a supine chest x-ray when the patient is lying flat actually has pretty poor sensitivity for pneumothorax. You need to have over 150 or 200 milliliters of air in the chest before you can start seeing that on a supine film. So really getting a patient into an upright position. And most of these are portable films, so not always easy to get the proper PA and lateral, but certainly putting that stretcher into as upright or semi recumbent position as possible, it’s really going to increase the sensitivity of plain film for pneumothorax.

Dr. Shreya Trivedi: And now that he talks about positioning the stretcher upright or semi recumbent, I feel like, duh, why haven’t I coach my patient to do that or write it in the comments so that when I’m ordering that portable chest x-ray, the tech can kind of help operationalize that.

Dr. Alexander Castro: Yeah, totally agree. It’s such a small change that apparently can make such a major difference. So now let’s move on to my favorite ultrasound, which in this case we typically use with a linear probe, a place between the rib spaces.

Dr. Mihir Parikh: And what you want to see is that there is that shimmering or that lung sliding or that ant margin, which correlates with the two pleural surfaces, the visceral and parietal pleural surface of the rubbing up against each other. When you lose that, when there’s a pneumothorax, right, the pleural surfaces have fallen off the chest wall, so you don’t see the visceral and parietal pleural surfaces in contact with each other. You’ll lose that lung sliding, and that’s called the absence of lung sliding or the loss of lung sliding, and that can be suggestive of a pneumothorax.

Dr. Alexander Castro: So just to hammer home the learning point – the ‘lung sliding’ is the movement of the pleura against the chest wall.

Dr. Shreya Trivedi: And so if you lose that sliding or shimmering on ultrasound, that means the pleural surface is no longer fully expanded.

Dr. Alexander Castro: But of course, not all things in medicine are so simple – and so not every loss of lung sliding means a puncture of the lining of the lung.

Dr. Mihir Parikh: I say suggestive of a pneumothorax, because it’s important to say that there are certain situations in which you can lose lung slide and not have a pneumothorax. And so that can happen in situations where the patient’s undergone a prior pleurodesis, right? So if the patient’s going to undergone a pleurodesis, that visceral pleural surface is stuck up to the chest wall, so you’re not going to see that sliding. If there’s poor respiratory motion as well too, you may just not see the patient sort of ventilating enough to move the lung in that shimmering motion. Certain patients with really bad bullous emphysema also can lose lung sliding even though the pleural surfaces are in contact with each other.

Dr. Alexander Castro: So it’s important to sort out any prior pleural procedures or surgeries, or any underlying lung disease before anchoring on pneumothorax as the only cause of a lack of lung sliding.

Dr. Shreya Trivedi: So that’s nuances on ultrasound. we also sat down with Dr. Darlene Nelson, IP at the Mayo Clinic when might you reach for a CT after seeing a pneumo on CXR?

Dr. Darlene Nelson: So if someone has underlying known emphysematous lung disease with a lot of bulla, sometimes on an X-ray, it can look like a pneumothorax, but it’s actually a large bulla and I’ve had several patients present with this and if there is a question, I would encourage a CT scan to make sure that it actually is a pneumo versus a contained bulla because I’ve seen patients come in and have chest tubes placed in bullae inadvertently as opposed to just actually having a pneumothorax.

Dr. Alexander Castro: Yikes, x-rays can fool you because a bullae can look like a pneumothorax and ultrasound could also fool you because bullae can result in loss of lung slider.

Dr. Shreya Trivedi: Exactly. And that CT scan is going to be great in giving us also the exact size of the pneumothorax and for visualizing any loculations in a complex loculated pneumothorax, which could be difficult to see on an X-ray or an ultrasound.

Dr. Alexander Castro: Alright! So to summarize, each major imaging modality for pneumothorax has pros and cons. Chest X-rays are fast and easy to obtain – but optimizing position with an upright image will greatly increase your yield and chances of catching a small pneumothorax. Ultrasound is an excellent and sensitive modality, but is operator-dependent – don’t be fooled by lack of lung sliding, and be sure to look at their one-liner for severe underlying lung disease or a pleurodesis!

Dr. Shreya Trivedi: And then CT can be a helpful tie breaker that gives you the full picture as of the size of the pneumothorax, the location, and then any underlying lung pathology that might be mimicking a pneumothorax like emphysematous disease.

Pearl 2: Initial PTX Management

Dr. Shreya Trivedi: So after we’ve diagnosed a pneumothorax, let’s get into who we should intervene on and who we should not.

Dr. Alexander Castro: Whenever I think about a pneumothorax, I just have this reflex to place a chest tube. I feel that pressure to place the interventional pulmonology consults and try to get that tube in as soon as possible.

Dr. Shreya Trivedi: But this is all good points to bring up. Do all pneumothoraxes get a chest tube? And then does it matter how big is it or is there something else that matters?

Dr. Darlene Nelson: My little maxim, which doesn’t always work – is first, ‘symptoms over size’ – and let me explain that a little further. So if I have a patient with underlying lung disease such as interstitial lung disease or emphysema or COPD, they can have a small pneumothorax, small to moderate, but be very symptomatic having increasing oxygen requirements, increasing tachypnea and in those situations I am going to intervene.

Dr. Shreya Trivedi: Yes, intervene indeed. So I guess what Dr. Nelson is saying is that it’s more about the clinical presentation than how big that pneumothorax is.

Dr. Alexander Castro: Exactly – signs and symptoms that would make you err towards intervening rather than watchful waiting. The most worrisome situation is tension pneumothorax – where air continues to get into the pleural space but can’t escape,and starts to compress structures in the thorax, making it harder to breath and harder for the heart to pump blood to the rest of the body.

Dr. Mihir Parikh: And so those are probably the most important clues you’re going to look for is sort of that combination of tachycardia, hypotension and jugular venous distension, right? The three sort of cardinal signs of tension physiology or something to certainly look out for and with that evidence of respiratory failure. But something to keep an eye out for, especially in the medicine world is evidence of subcutaneous emphysema, especially around the neck and the upper torso and voice changes or difficulty swallowing.

Dr. Shreya Trivedi: So when we get called to the bedside for someone with a pneumothorax, we’re going to look at the vitals to see if there’s any tachycardia, low blood pressure, look at the patient, right? See if there’s any jugular venous distension. And worst of all, look for any subcutaneous emphysema, which is most often under the skin in that neck, chest area.

Dr. Alexander Castro: And so in cases of tension pneumothorax, emergent needle decompression or emergent chest tube placement is going to be the next step.

Dr. Shreya Trivedi: Yeah, I hope I never have to be a part of any emergent decompression or chest tube placement. I haven’t and I hope I never will. But now that we talked about those scary stuff, let’s talk about when it isn’t tension physiology and how do we approach a patient who is a bit more stable?

Dr. Mihir Parikh: There’s actually a large study that came in from Australia and New Zealand. There’s a randomized controlled trial of patients with moderate to large, so not even small, moderate to large spontaneous pneumothorax. And so what they did is they randomized these patients to two arms. The first was routine management, which was I said was the old algorithms where you went based on size or symptoms and put in the tube versus the conservative arm, which was to walk the patients around the emergency room if they were able to do so without difficulty and without desaturating and a repeat chest x-ray done after four hours showed no interval worsening of pneumothorax. They were discharged home with no intervention and they found their primary outcome measures were of course need for additional interventions or return to the emergency room and found no difference between these two groups.

Dr. Shreya Trivedi: Wow. So a moderate to large spontaneous pneumothorax can just be watched. Man, I am so glad there’s some solid data to also back up that ‘symptoms oversized mantra’,

Dr. Mihir Parikh: And you’ll see that reflected now with the newest British guidelines for pneumothorax, for spontaneous pneumothorax don’t actually have a size criteria in their algorithm. It’s more based on symptoms. And so that’s why now I’m starting to move more towards that where even patients with a moderate pneumothorax see how they’re feeling. If they’re having chest pain, discomfort, feeling short of breath, certainly intervene, but if not, watch them for four hours if the pneumothorax isn’t growing and they’re not developing symptoms and I think it’s reasonable to keep an eye on them but not put in a tube.

Dr. Alexander Castro: Definitely – I was surprised that so many patients can just be watched, but I’m glad we don’t have to subject every patient with a pneumothorax to a chest tube.

Dr. Shreya Trivedi: Right – thankful that not putting tubes in aka close monitoring can be part of the treatment plan for asymptomatic PTX! But let’s say our patient is relatively stable but symptomatic, without signs of tension pneumothorax. So all signs are pointing towards a chest tube in the near future. So how should we explain why they need the chest tube

Dr. Alexander Castro: I really liked how Dr. Van Holden, an Interventional Pulmonolgist at the University of Maryland, explains this to her patients:

Dr. Van Holden: So when I explain pneumothoraces to patients, I like to inform patients there is some sort of injury in the lung that is creating a hole, so when you’re breathing in the air, it’s leaking out of this hole into the space between the lung and the rib cage and it’s building up air. The chest tube would be a small tube that would be placed between the ribs in order to help drain that air so that the lung can expand. Again, you can kind of think of the lung as a balloon and when the air is escaping, the balloon is kind of deflating and you’re trying to release that air between the ribs and the lung so that the lung can expand again.

Dr. Shreya Trivedi: Nice it’s good imagery thinking of the lung as a deflating balloon in the chest wall and air is leaking out. That chest tube that we are gonna put in is gonna help drain out the air that is trapped in btw the chest wall and ballon and let the balloon or lung expand again!

Dr. Alexander Castro: And then last but not least the other arm of management is pain control. chest tubes are pretty uncomfortable – and I appreciated hearing Dr Parikh’s his anecdotal experience on who may have more or less pain with chest tube placement.

Dr. Mihir Parikh: I have found that I think patients with normal lungs, like normal lungs tend to have more pain. I think the reason for that is patients with sort of secondary spontaneous pneumothoraces, they have underlying disease lungs, they’ve probably had some interventions in their chest or have had some underlying lung pathology. So the pleural surface I think does become sort of like chronically abnormal over time, whereas patients who have normal lungs therefore have normal pleural surfaces tend to have more because I think their pleural surfaces just tend to get irritated more often. And these primary spontaneous pneumothoraces tend to be in these lanky young men. And I don’t know if it’s just our own biases about their pain tolerance, but they do tend to need more pain control than other patients I’ve found.

Dr. Shreya Trivedi: Yeah i’m glad we brought this up. Refreshing to check our own biases about how different pleura may response to chest tube and relatively “normal” pleural surfaces may be more sensitive than pleural surfaces that have already seen a lot of disease

Dr. Alexander Castro: So to summarize PTX mgmt – ‘symptoms over size’ is the name of the game. For patients with little to no symptoms, regardless of size, even large PTX, conservative management can be a reasonable strategy! But for patients with signs or symptoms like dyspnea, tachypnea, and tachycardia, placing a chest tube makes sense. And don’t forget to keep a close eye out for signs of hypotension, tachypnea, jugular venous distension, and subcutaneous emphysema – which suggest tension physiology and warrant immediate intervention.

Pearl 3: Understanding the Pleural Drainage System and What to Monitor

Dr. Shreya Trivedi: All right, Ah, man, let’s get into all things about the different causes. Limbs of the chest tube, aka the plural drainage system. And this whole section was just a wonderful eureka moment to me, to the point where I look back, I’m like, Did I ever know any of this before? I thought I did. I used to use these words, and I think just speaks to you know how great some of the discussions were.

Dr. Alexander Castro: Totally agree! Water seals, pressures, gradients, suction adjustments – where to start when bending down & looking at the chest tube chamber, and then where to go based on what you see.

Dr. Shreya Trivedi: Yeah, I love the way Dr PARIKH broke down each chamber. Or maybe another way to think about it, is there, you know, there’s three different parts of the drainage system. And now the drainage system is kind of inverted. We’re going to look at it going from right to left. And so the first chamber, which is where air from the patient’s lung goes into, is on the right side, and then we’re going to move left. So that first chamber is called the collection chamber, and there’s three different columns on the right side.

Dr. Mihir Parikh: The first chamber is the collection chamber, so that’s the chamber that comes off the patient first, and it’s literally just a collection chamber. It’s a glorified graduated cylinder. I say it’s really a way for us to measure plueral fluid output per unit time, less relevant in a discussion of pneumothorax, but certainly important in other patients like with a hemothorax or a pleural effusion for some other reason where you really want to get a sense of how much fluid’s coming out per hour per day and so on.

Dr. Shreya Trivedi: So that first column chamber is those three columns, and they can hold up to 2000 CCS. And this is where we’re going to see markings from nurses with dates and hours and timings to track how much fluid might be collected out of the drainage system. Now, typically we could ignore this collection chamber in a pneumothorax, but just to say it out loud, our body does produce 10 to 50 cc’s of pleural fluid a day, so don’t be alarmed if you see a little bit of pleural fluid there.

Dr. Alexander Castro: Exactly. And for pneumothorax, what you really want to look at is the second chamber, which is also known as the water seal chamber. In most drainage systems this is usually in the corner, usually a vibrant blue color because it’s literally filled with water. And this has two major purposes, the first is protective, and the second is diagnostic. So let’s start by understanding how this chamber helps protect our patients.

Dr. Mihir Parikh: The second chamber is the water seal. And so this is an important one because this is the way that we protect patients when they have a chest tube in place. Remember that intrapleural pressure is negative to the ambient environment. And so if you just had a tube coming out from the patient’s chest in the pleural space, there would be a gradient for air to move into the chest because pleural pressure is negative and that would cause you to have a pneumothorax again and sort of defeat the purpose of putting in a chest tube to begin with. And so that’s where the water seal comes in. So the water seal is just a thin column of water that is pretty easy for for air or fluid or air to displace away from the patient. And so that’s the beauty of the water seal. It really only allows air to move in one direction away from the patient.

Dr. Shreya Trivedi: So the water seal is a one-way valve that allows air to exit the pleural cavity during exhalation but does not allow it to re-enter during inhalation.

Dr. Alexander Castro: And so because this chamber is such an important protective mechanism, one thing to make sure of is that there’s actually water in the chamber itself. Make sure it hasn’t spilled or evaporated. Or that someone didn’t forget to put water in there

Dr. Shreya Trivedi: But yeah, I think the real money when it comes to water seals is the diagnostic portion of it, and when it comes to the water seal chamber, it’s particularly diagnostic for something, what we call air leak. And it’s something that’s a term we throw around all the time, but just crystal clear, what is an air leak.

Dr. Alexander Castro: So an air leak is literally bubbling within the water seal chamber itself. And if you see bubbling, that represents that there’s still a pneumothorax present. More precisely, an air leak means that air is still flowing from the pleural cavity and then into the chamber.

Dr. Shreya Trivedi: Yes so it sounds like there’s still more air being trapped in that pleura. When we see that bubbling

Dr. Mihir Parikh: The water seal is where we’re going to look for the air leak. So that’s really something to keep an eye on when you’re examining patients with pneumothorax every day because that’s going to really help you if the air leak persists. But that’s where you’re looking to see if there’s ongoing air moving out of the chest or moving out of the pleural space, which is consistent with an air leak, meaning the hole in the lung hasn’t healed yet. So it’s always good to just do a quick look to make sure that, is there water in the water seal and are you seeing bubbling to suggest an air leak?

Dr. Shreya Trivedi: And because this water seal chamber is so important in the management pneumothorax, we’re going to dedicate a whole Pearl, our next Pearl, into what we’re actually looking at when we look at the water seal chamber to see how bad that air leak is, or is it just normal titling, but before we get into there, let’s round out our discussion on the three different parts of the adrenal system with a third and last part, which is the suction control chamber.

Dr. Alexander Castro: So suction is extra negative pressure that’s used to help air flow out of the pleural space. One key point to understand about how the chest soup works is that air moves from areas of high to low pressure. Hence why interventional pulmonology is asking you to set the suction to digits in the negative to create that gradient for air to move through.

Dr. Shreya Trivedi: Man, I had such a big aha, because I think I never really understood why they were paging me, you know, or my team to change it to a negative 30 suction or negative 20. But then when I relearned, or the six. So humbling, like when you relearn the basics, and like, why you had to relearn it in the first place, when I relearned the basics, that the interplural pressure of is usually negative four or negative five. Your point that air moves from high pressure to low pressure, made so much sense, because, of course, we need to set the suction to something lower than negative five or negative four, and so that’s going to be more effective to move that air from the intrapleural space to the drainage system.

Dr. Mihir Parikh: Most times when you’re connecting the chest tube to suction the chest tube or the pleurevac is set at minus 20 centimeters of water. That’s just an arbitrary setting that we set it at, whereas when it’s actually connected to the wall, the wall suction is routinely set it negative a hundred or sometimes negative 200, or sometimes it’s just cranked to max depending on whoever’s in the room setting it up. And so let’s give a hypothetical example in which that suction control chamber didn’t exist and we just connected chamber number two directly up to the wall suction and therefore exerted negative a hundred to negative 200 centimeters of water pressure on the chest. And remember that normal pleural pressure is probably about negative four or negative five. So if you were to put someone with a chest tube to negative a hundred negative 200, that’s going to be extremely painful and probably pretty dangerous as well too because you’re going to rip open the wall. And so that’s where that section control chamber really comes into handy because what that is is a sort of intermediate step between the water seal and the wall suction.

Dr. Shreya Trivedi: So to break that down, we really need that suction control to be that middle man between the water seal chamber and the wall suction, which can be set to crazy high pressures, like negative 200 which would be pretty dangerous for our patients.

Dr. Alexander Castro: And so if you’re curious as to how the suction control chamber protects our patients from those really negative pressures, the suction control chamber actually has a pop off valve that’s open to the ambient environment. And once the system has hit a certain level of suction or of negative pressure, this valve opening and closing regulates the pressures.

Dr. Shreya Trivedi: Great. I’m glad we’re talking about this, because I think, practically speaking, now when I go look at the chest tube of the pleural drain system, I’m going to look for that circle knob again. There’s different types of pleural drain systems, if it’s a dry suction chamber. Usually on the top left there’s a circle knob, and I can just exactly see, you know, what the suction is set to. And I think the other thing that interventional palm often pages this about is to move that suction to this member, and then move it down, and then move it up, and then sometimes it just feels like a cycle. And I think I never really appreciated the nuances as to why

Dr. Van Holden: When chest tubes are placed for pneumothoraces, it’s really this balance between having the lung expanded with suction, however that airflow with suction is going to perpetuate that airflow gradient across the alveolar-pleural fistula, which may impair its ability to heal. So the amount of suction is you want to remove enough air for the lung to expand, but not so much that it’s not going to allow the fistula to heal. So removing patients off of suction as quickly as possible is the goal.

Dr. Alexander Castro: So suction is really a double edged sword. It can help remove air from the pneumothorax more quickly and cause the lung to re expand, that can also drive more air from the actual lung into the pneumothorax itself. And if the suction is too strong, it might impair the healing of the actual defect in the pleura.

Dr. Mihir Parikh: So that’s why sometimes we’ll go up to minus 30 and minus 40, we’ll see the bubbling continue, but really no improvement in the lung not coming up. We’ll say, okay, that didn’t work. Let’s go down on this suction now. And so we’ll start working our way down from minus 30 to minus 20, minus 10, maybe minus five. And again, try to get to a point where we’re able to remove enough air from the chest without the patient becoming symptomatic, but also allowing that hole to kind of slowly seal itself off as we decrease the gradient for air to move across that pleural defect. And that’s where there’s a lot of talking to the patient just saying, Hey, we’re just doing a little bit of trial and error to see if we can balance getting the air out of your chest with getting this hole to heal.

Dr. Shreya Trivedi: So that anticipatory guidance that we’re trying to find that fine balance between getting as much air out but also allowing the hole to heal.

Dr. Mihir Parikh: And so that’s what we’re looking for every day. And what we’re trying to do is get that air leak to slowly resolve to get the patient on less and less suction and then get ’em off to water seal the benefit of getting a patient off of suction onto water seal. And that means that when we say that patient’s on water seal, it just means that they’re not on suction anymore, they don’t need to be on suction. And the benefit of that is that that usually means that the air leak has improved to a certain point that the patient’s able to tolerate just being on water seal, meaning that if you take ’em off so much air is not generating is being generated in the chest, that their water seal can keep up with it, that you actually need to exert more suction onto them. And the benefit of that, as I was saying, was really to allow patients to be free of the wall because when they’re on suction, they’re just literally tethered to the wall or they need some sort of portable suction device.

Dr. Shreya Trivedi: And just to say it loud, if interventional palm says, you know, let’s put the patient off suction. That means, by default, the patient is going to be then put on water seal and here with water. Seal. Its gravity alone is enough to help the pneumothorax resolve. Again, the such a high yield teaching on the different section of the drainage system. And every time we go through, I’m like, Ah, another point, clicks browser, why don’t you summarize?

Dr. Alexander Castro: Sure. So after the collection chamber, which is less important for a pneumothorax, the next chamber will be the water seal. Remember, the intrapleural pressure is negative, and air flows from high to low. So the water seal chamber ensures air only flows out of the pleural space. It prevents the pneumothorax from expanding. On top of that, it allows for visualization of an air weak which is diagnostically useful for pneumothorax.

Dr. Shreya Trivedi: And the last one is a suction chamber, which is usually on the left hand side. And depending on the system you’re using, it might be a circled knob so suction is added to help draw out more air from the chest, and this chamber looks like a dial to show what degree of suction is being applied. And it also is needed, because once the specific pressure is set, the valve pops off and closed to ensure that the amount of pressure is stable to prevent patient injury.

Pearl 4: Air Leak Monitoring

Dr. Shreya Trivedi: So now that we’re oriented to the three different parts of the drainage system, let’s get to what we really are going to be looking at every day in a patient with a pneumothorax, which is that second chamber, the water seal part. Now we’ve already mentioned the water seal is where we’re going to check to see if there’s bubbling and if there’s an air leak. But I think there’s so many questions here, right? Like, is all air bubbles mean air leak.

Dr. Alexander Castro: All good questions, but first things first, and or near that water seal chamber, there’s usually a small white ball. And if you see that ball moving up and down with respiration, this is called tidal wave, and that’s to be expected with normal breathing.

Dr. Mihir Parikh: And what you want to see that is that with the respiratory cycle, you want to see that fluid kind of moving in and out a little bit. And sometimes it’s a subtle movement, sometimes it’s a very exaggerated movement, but you do want to see some motion as the patient breathes in and out because as the patient breathes in, pleural pressure gets a little negative, the fluid moves towards the chest as the patient breathes out, pleural fluid, pleural pressure gets a little positive, fluid moves away towards the PLE back, and you want to see that.If you’re not seeing that, then that might be another indication that the chest tube is kinked or for some reason someone clamped it and didn’t realize that they did.

Dr. Shreya Trivedi: So tidaling is just a visual demonstration of pressure changes with normal breathing. Typically a fluid in the chest tube itself, and so water in that water seal with a little white ball should rise towards the chest with inhalation and fall away from the chest with exhalation, that’s indicating that the chest tube is working properly.

Dr. Alexander Castro: So this movement of fluid up and down is different from bubbling. And bubbling is bad. And bubbling means there is an air leak, which means there’s still a pneumothorax, but there’s a surprising amount of depth to how we can measure and quantify this to get a sense of what’s going on in the pleural space.

Dr. Mihir Parikh: And so the one thing that I’d like to explain to teams as well as patients too is sort of how do we measure the air leak? How do we know that there’s still air coming out of the chest, meaning that pleural defect, that hole in the pleural surface is still there. And so that’s where we’re looking for bubbling in the water seal. And the way that we try to, we’ve come to quantify that is something called our Cerfolio classification for air leaks, which is a really simple classification system. It’s really easy, really reproducible, and so it’s sort of become the standard for monitoring or measuring air leaks. And so the worst is a grade four or a continuous air leak. And so that’s regardless of if the patient’s breathing in, breathing out, holding their breath, you just see a constant stream of bubbles in the water seal that’s a continuous or a grade four air leak.

Dr. Shreya Trivedi: And now you can always look up this Cerfolio classification, quantify air leaks. And grade four being the worst compared to grade one or having no air leak. You don’t have to memorize these, but I did find it helpful, at least for me, to hear the differences and understand the IP speak a little bit more.

Dr. Mihir Parikh: A grade two air leak is an intermediate, it’s called an intermittent expiratory air leak. And so this is where you don’t see continuous air leak anymore. The leak’s gotten a little bit better. So the patient breathes intrathoracic pressure drops a little bit, so you see the air leak resolves, you don’t see bubbles, patient breathes out or exhales, and you’ll see a couple of bubbles as intrathoracic pressure goes up a little bit. So you sit there and watch the patient just kind of breathe comfortably for a couple of respiratory cycles and you’ll see no bubbles and inspiration bubbles, expiration no bubbles, inspiration bubbles, expiration. So that’s a grade two. The grade one is the smallest air leak, and so that’s called a forced expiratory air leak. So when you come into the room, just talk to the patient or if they’re just breathing comfortably tidally, you’ll look at the PLE vac and you won’t see any bubbles at all, but you’ll ask the patient to do a forced expiratory maneuver. So take a deep breath in and blow out as far as you can cough or maybe bear down and do a Valsalva and that’ll spike into thoracic pressure and you’ll see a couple of bubbles come out. And so that’s what I explain to the patients when I’m examining them, just say, I’m just trying to measure how bad the leak is in terms of how much pressure it’s required for you to generate to get some bubbling to create this air leak. So what we like to see every day is from the patient to go from a continuous to an intermittent expiratory air leak to a grade one or a forest expiratory air leak, that means that the air leak is improving.

Dr. Shreya Trivedi: I feel like, before I heard this, I would just like, kind of squint at the water seal part and see, like, how much bubbling I was seeing. Is it less bubbling than what I remember yesterday? But it sounds like I should be really looking at that bubbling and how it compares to the respiratory cycle. I curious. Alexander, is it something like you’ve actually. Done, and I don’t know, like, I can imagine some patients, like, is that inhalation? Is that exhalation?

Dr. Alexander Castro: Yeah, I’ve definitely seen pulmonologists ask patients to do all of these maneuvers, deep breathing, bearing down, or even just normal talking and then staring at the drainage system throughout to try to track these changes with where they’re occurring in the respiratory cycle.

Dr. Shreya Trivedi: So big picture here is every day we’re trying to move the needle forward for our patient, helping them go from suction to being off suction, aka being on water seal, and then from there, hopefully having no air leak enough to do something called a clamp trial. This is our last step before removal of that chest tube, and it’s basically a test run for the patient to see how they would do without that chest tube, without actually taking the chest tube out.

Dr. Mihir Parikh: And the important thing about a clamped tube is it’s basically not having a chest tube at all. And so you really want to be mindful of monitoring that patient and communicating with everybody about what you’ve done, including the patient. And so when I’m clamping a chest tube, I will show them, I’ll say, Hey, this is me clamping your chest tube. If you start having chest pain, if you start having shortness of breath, if you don’t feel good, call for help and unclamp your chest tube and this is how you unclamp it. And so in most patients, they’re able to be empowered to do that on their own.

Dr. Alexander Castro: And so the biggest takeaway about a clamp trial is that patients should be able to look out for any symptoms like shortness of breath or chest pain that might indicate they’re not quite ready for the tube to come out yet, and they should feel empowered if they’re able to even reclamp the tube themselves if these symptoms come out. All

Dr. Shreya Trivedi: Alright, this has been a lot of great information, and so why don’t we summarize what we’ve learned so far?

Dr. Alexander Castro: So the water seal chamber is where you can visualize titling, as well as an air leak up and down, movement of fluid within the tube or of the indicator ball with respiration indicates a normal chest tube function. But loss of this titling with the indicator ball can indicate kinky in the chest tube, or displacement of the tube.

Dr. Shreya Trivedi: Right. And then if you see any bubbling, that means that there is an air leak, a hit, the pneumothorax is still present. And I think I’ve learned that if I ask a patient to take a slow breath in and how I can better characterize the degree of bubbling and how bad that air leak is.

Pearl 5: Persistent Air Leak Management

Dr. Shreya Trivedi: So now we discuss the back and forth between suction and water seal that could happen, but say this air leak is just not going away. Every day we’re going in, we’re still seeing that bubbling in that water seal chamber. What do we do?

Dr. Mihir Parikh: Usually we will start doing these maneuvers over the first four or five days because once we hit day five, that’s where we start hitting the definition of what we call a persistent air leak. That’s just some sort of arbitrary time point day five where we call it a persistent air leak. And we say, okay, now we need to start doing some of these other things to start, try to get this moving along so we can get this patient home.

Dr. Alexander Castro: So five days is typically the mark to think about. And at that point, there are three major options, blood patches, endobronchial valves and pleurodesis.

Dr. Mihir Parikh: One of the things that we commonly think employ something called a blood patch, and it’s an autologous blood patch, and so we’re using the patient’s own blood in that scenario, not a lot of evidence to support its use, but the case series that have been reported so far have shown some success. So what we do is we literally take a hundred to 120 ccs of the patient’s own blood and that inserted by the chest tube into the pleural space, but the goal being that blood will hopefully find its way to this pleural defect and create a clot over it that will then sort of patching a tire. There’s also some pleurodesis that happens because blood is a partial PLE agent, and so you will get some pleurodesis as well too to get the lung to stick up to the chest wall. The biggest risk to a blood patch is infection, and it’s because it’s basically like adding culture media to wherever you’re putting it.

Dr. Shreya Trivedi: So basically a blood patch is using a little bit of that patient’s blood, about like a third of a soda can, you know, 120 CC. And then interventional pulmonologists are putting that blood through the chest tube to help patch up the hole in the lung. Hence, it’s called a blood patch.

Dr. Darlene Nelson: This can be done several times, so sometimes if you look in the literature it would suggest upwards of a 70 80% success rate with initial blood patches. Clinically speaking, I haven’t found it to be that high on initial trial, but sometimes on a second try we’ve gotten a lot more success or sometimes even a third. So blood patch is a good option. One thing to think about with that is that if a patient’s on anticoagulation, so if they’re on a apixaban or if they’re on a heparin infusion, that’s going to make your blood patch less effective than if they’re not on anticoagulation.

Dr. Shreya Trivedi: And hopefully anticoagulation can be held long enough so that the blood patch can do its thing. But yeah, this seems like a real advantage in trying something that’s not invasive and less permanent than some of the other options.

Dr. Mihir Parikh: The other options are endobronchial valves, which is something that’s really come a long way in the last five to 10 years as a wonderful tool for patients with persistent air leaks. And so these are one-way valves and they’re placed bronchoscopically, and so they allow, in whatever segment you place them, they allow air to move approximately so for air to come from the lungs to the central airways and breathe out, but they don’t let any further air go out into that segment.

Dr. Shreya Trivedi: So an endobronchial valve is another great tool, but again, it does require an invasive bronc, and risks come with that, of course, with sedation and all.

Dr. Alexander Castro: Lastly, pleurodesis is an option for both persistent air leak as well as for prevention of pneumothorax recurrence.

Dr. Darlene Nelson: So if a patient’s air leak is persistent but low so that they can have some time off suction, again, you can give four grams of sterile talc into the pleural space. Caveat to know about talc pleurodesis as it can be painful. So typically we’ll have access to pain medications for the patients and we also instill 300 milligrams of lidocaine into the pleural space before administering the talc to help make it less painful.

Dr. Shreya Trivedi: So to summarize, air leaks are defined as persistent after five days, and there’s a variety of different ways we can deal with it. One is a blood patch where we’re literally using the patient’s blood to help patch up the hole in the pleura. Second is an endobronchial valve placement, which requires an invasive bronch procedure. And then lastly, pleurodesis, where the tout can be quite painful, and each come with its different risks and may be suited for different patients

Dr. Alexander Castro: So that wraps up our episode on pneumothorax.

Dr. Shreya Trivedi: And if you got any value from this podcast, our ask is to please share this with at least one other colleague that could also use a nice aha moment. I know I certainly had tons of actually eureka moments from this. Thank you to our peer reviewers, Dr Laura Frye and Dr Daniel Dunlap. And as always, we love hearing feedback, so please email us at [email protected] opinions expressed our own and do not represent the opinions of any affiliated institutions. Thank you. Take care.

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