Tension Pneumothorax
If you’re a new paramedic wanting to learn more about trauma and tension pneumothorax, or a seasoned medical provider wanting to refresh on a skill they have performed numerous times… you’re in the right spot.
Today, let's discuss tension pneumothorax and all the fun things that encompass this very important diagnosis. Not only is identifying a tension pneumothorax critical and time-sensitive, it is also very important that we know how to perform a needle decompression appropriately, effectively, and efficiently.
Anatomy and Physiology
We have to know what we are dealing with and why we are doing what we are doing, and that starts with anatomy. Our chest contains our thoracic cavity which starts at the lower airway (trachea) to the start of the diaphragm. In the thoracic cavity, we house some pretty important organs that are vital to our existence. Two major cavities in the thoracic cavity include the pleural cavity and the mediastinum
The Mediastinum is the space between the lungs that contains our great blood vessels, the heart, and the trachea. This space starts at the clavicle and extends to the diaphragm. Major blood vessels include the inferior and superior vena cava feeding into the right atrium, pulmonary arteries and veins, and the aorta. The heart sits in the mediastinum with the apex of the heart extending into the left side of the chest.
The pleural cavity contains our lungs, two to be exact. The apex of the lung is located under the clavicle with the base of the lungs resting on the diaphragm at about the 6th rib. The right lung contains three lobes and the left lung contains two due to the heart taking up some of that left side. Normally, the thoracic cavity is occupied by the lung, held to the chest wall by the pleural membrane’s surface tension. The Pleurae is a membrane that separates the lungs from the chest wall. The Visceral pleura lines the outside of the lungs and the Parietal pleura lines the inside of the chest wall. Between these two membranes is a lubricating fluid. This fluid is like putting a thin layer of water between two pieces of glass, they glide smoothly but are difficult to pull apart. Along with negative pressure, the lubricating fluid helps hold the lungs tight against the chest all while sliding smoothly during respiration. (4)
During respirations, we use our diaphragm and our intercostal muscles for both inspiration and expiration. When we draw a breath in, our diaphragm and intercostal muscles contract. Our diaphragm flattens and our intercostal muscles pull our rib cage out. The lungs are forced to comply and expand. This creates a negative pressure compared to our atmosphere. Air then rushes in to help equalize this pressure in your lungs compared to the atmosphere. Expiration on the other hand is passive. Once the diaphragm relaxes, a positive pressure is created and air flows out.
Tension Pneumothorax
Pneumothorax is a condition that occurs when air enters the thoracic cavity between the Visceral and parietal pleura via a one-way valve. This could be caused by a leak in the lung and/or a hole in the chest wall. The air disrupts the surface tension being held by the parietal and visceral and the lung collapses.
A Tension Pneumothorax is when that air accumulates in the thoracic cavity and not only collapses the lung but also places pressure on the mediastinum, compressing the heart, decreasing venous return, shifting the mediastinum, and compressing the opposite lung. Hypoxia and obstructive shock are two of the biggest issues with a tension pneumothorax
Hypoxia: Gas exchange occurs across the respiratory membrane of the alveoli. When our lungs is collapsed, our alveoli are not open and gas exchange of CO2 and Oxygen doesn’t happen.
Obstructive shock: With a mediastinum shift, our heart and vena cava is compressed. This produces a significant decrease in venous return, decreased preload and the heart is unable to contract properly. Cardiac output is significantly decreased.
Signs and Symptoms
When assessing our patient for a tension pneumothorax there are quite a few signs and symptoms to look for. Along with indications for a pneumothorax such as trauma, we have tachypnea, tachycardia, absent breath sounds on the affected side, hypoxia, anxiety and air hunger are very good initial assessments that we can gather. As the tension pneumothorax progresses or worsens, we develop signs of obstructive shock. Our heart is inhibited from filling, contracting, and producing adequate cardiac output. We develop cyanosis, confusion, profound hypotension, jugular vein distension (JVD), and tracheal deviation to the unaffected side. Tracheal deviation and JVD are late- late finding and honestly, I hate mentioning them because they should be the last things we are looking for, and hopefully we have diagnosed the problem by then.
I’m going to make a bold statement that may make us feel uncomfortable. However, a tension pneumothorax is a life-threatening condition and treatment/intervention should not be delayed for diagnostics such an x-ray or monitoring.
**A tension pneumothorax can be identified without our monitor. **
Let’s touch on this real quick. Think about it, we arrive at our patient we gather our “across the room assessment”, and before we ever apply a monitor, we assess our ABCs, right? (in theory). Across the room, do they appear anxious or air hungry? Is our breathing asymmetrical with noted or known trauma and absent breath sounds? Is our circulation cool, diaphoretic, and pale with possible cyanosis noted? How about our radial pulses? Are they present? There we have it, assessing for a tension pneumothorax without a monitor… like a boss!
I would like to add: follow your local guideline and protocols. Of course, if you are not hitting all or most of these “checks” on your assessment, apply your monitor. The goal is simple, delay treatment as little as possible.
PEARLS
Air Medical transport: The importance of identifying a simple pneumothorax prior to transport is imperative. Altitude can result in an expansion of the simple pneumothorax leading to a tension pneumothorax. This is related to Boyle’s law.
Ventilator: Positive pressure ventilation can exacerbate an air leak or an already weakened pleural tissue. Positive pressure ventilation is correlated with high peak inspiratory pressures (PIP), high tidal volumes, and the development or worsening of a pneumothorax. A simple pneumothorax or a tension pneumothorax that has been relieved with needle thoracostomy can worsen and become a tension pneumothorax, or re-tension with positive pressure ventilation. Be cognizant of your ventilator and their settings when placing a patient on the ventilator. Monitor your patient’s vital signs closely watching for: tachycardia, hypoxia, hypotension, decreasing ETCO2, and high frequency versus rate set in conjunction with elevated PIPs and Pplats. (2)
Percussion: HA-HAHAHA, because we can all hear the hyper resonance in the back of an ambulance, helicopter, or a noisy trauma bay. Sorry, I had to say it. All I can imagine is some guy standing over a patient dying and percussing his chest, intently listening while everyone watches the patient circle the drain. Moving on. 😑🙄
Interventions: These range from simple BLS interventions to ALS/Critical care interventions. Applying an NRB at 15L plus, performing a needle decompression, chest tube, or finger thoracotomy with guidelines permitting, are all appropriate interventions that we can do for a tension Pneumothorax.
Needle Thoracostomy
Needle thoracostomy is the passage of an angiocatheter into the pleural space to allow air that has accumulated under pressure to be released. This life-saving intervention allows a tension pneumothorax to evacuate a majority of the air, reversing the hemodynamic compromise that would have resulted in a patient expiring. The pressure on the mediastinum and lung is relieved, leading to a rapid improvement of venous return, oxygenation, and ventilation. If you have never needle decompressed a tension pneumothorax you’re in for a real treat. It is something really fascinating to watch.
According to this article, “Complications of needle thoracostomy: A comprehensive clinical review”, ineffective catheter placement is the most common complication which is associated with 22-50% failure rates (7). There are many factors according to this study that affects this which include: chest wall thickness, needle length, and patient characteristics (breasts, or obesity). This makes not only knowing how to perform a needle decompression difficult but also knowing how to adjust for anatomy purposes difficult.
We have to know our landmarks and how to identify them. There are three main landmarks that are commonly used. For purposes of consistency, we will be talking about needle thoracostomy being performed with the standard 3.75-in 14-G/10G angiocatheter. (moans and groans, I know people!) While needles that are longer have a higher success rate, they also have an increased risk of injury to underlying structures, but also noted that shorter needles have a higher fail rate. What poison are you going to pick?
With each landmark, we will take the same approach with our angiocatheter. With palpation of the correct rib/ intercostal space, we insert our angiocatheter at a 90-degree angle, above the rib of our identified intercostal space. This is to avoid the neurovascular bundle underlying each rib. By placing the angiocatheter above the rib, we avoid disruption and damage to the neurovascular bundle.
Our most commonly used sites:
1. Midclavicular: 2nd intercostal space.
2. Mid axillary: 4th /5th intercostal space.
3. Anterior Axillary: 4th /5th intercostal space.
Next with insertion of the needle, we are trying to feel for a pop or sudden decrease in resistance with insertion. This should signal to us that we are in the pleural space and now we can advance our catheter off of the needle and into the pleural space, removing the needle. (5) DO NOT hesitate to re-needle if you are not seeing improvement, or if you suspect you are re-tensioning again.
I cannot tell you which site to use as I’m not here to debate that. What I can do is two things. Tell you to follow your protocols and guidelines and give you resources to decide for yourself. REBELEM did a great job breaking down failure rates of each placement as well as catheter length associated with injury and success rates (6). REBELEM.
Conclusion
A tension pneumothorax is a life-threatening condition and recognition with rapid treatment is critical. My first experience seeing someone with a tension pneumothorax was very eye-opening. I really hope that by reading this blog, you were able to learn something new or reinforce something you have already learned.
Thanks for reading. Peace out. ✌️
Brittany Grandfield. Flight Nurse.
Citation
1. Advanced Trauma Life Support: Student Course Manual. American College of Surgeons, 2018.
2. Hsu, Chien-Wei, and Shu-Fen Sun. “Iatrogenic Pneumothorax Related to Mechanical Ventilation.” World Journal of Critical Care Medicine, Baishideng Publishing Group Co., Limited, 4 Feb. 2014, www.ncbi.nlm.nih.gov/pmc/articles/PMC4021154/.
3. Huggins, John. “Thoracostomy Tubes and Catheters: Placement Techniques and Complications.” Uptodate, 4 May 2021, www.uptodate.com/contents/thoracostomy-tubes-and-catheters-placement-techniques-and-complications?search=needle+thoracostomy&source=search_result&selectedTitle=1~69&usage_type=default&display_rank=1#H3199420612.
4. Jarvis, Carolyn. Physical Examination & Health Assessment /: 7th Edition. Elsevier, 2016.
5. McEvoy, Mike, et al. Critical Care Transport. Jones & Bartlett Learning, 2018.
6. Rezaie, Written by Salim. “What Is the Best Anatomic Location for Needle Thoracostomy?” REBEL EM - Emergency Medicine Blog, 21 Mar. 2019, rebelem.com/what-is-the-best-anatomic-location-for-needle-thoracostomy/.
7. Wernick, Brian, et al. “Complications of Needle Thoracostomy: A Comprehensive Clinical Review.” International Journal of Critical Illness and Injury Science, Medknow Publications & Media Pvt Ltd, 2015, www.ncbi.nlm.nih.gov/pmc/articles/PMC4613415/.
8. Holleran, Renee, et al. Patient Transport - Principles and Practice. 5th ed., Elsevier - Health Sciences Div, 2018.