Needle Decompression: Indications, Sites, Needle Length, and Complications Practice Questions

25 multiple-choice questions on Needle decompression: indications, sites, needle length, and complications for paramedic and EMT students, from Chapter 36 (Chest Trauma). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. After a crash, which patient most clearly needs needle decompression?

   1. A. Diminished breath sounds and SBP 130 mmHg
   2. B. Absent breath sounds, JVD, and SBP 70 mmHg
   3. C. Rib crepitus, SpO2 95%, and SBP 120 mmHg
   4. D. Sucking chest wound, SpO2 94%, SBP 118 mmHg
   Show answer

   Answer: B. Absent breath sounds, JVD, and SBP 70 mmHg

   Needle decompression is for a suspected tension pneumothorax with respiratory or circulatory compromise. A stable patient with diminished breath sounds may have a simple pneumothorax, which is monitored rather than decompressed.

2. The traditional anterior site for needle decompression is the:

   1. A. 2nd intercostal space, at the sternal border
   2. B. 5th intercostal space, midclavicular line
   3. C. 7th intercostal space, posterior axillary line
   4. D. 2nd intercostal space, midclavicular line
   Show answer

   Answer: D. 2nd intercostal space, midclavicular line

   The second intercostal space at the midclavicular line is where air collects in a supine patient and is away from the heart. Inserting at the sternal border risks the internal mammary artery.

3. A patient with severe COPD arrests after aggressive bag-valve ventilation. Ventilation becomes very difficult, and breath sounds are absent on one side. You should consider:

   1. A. Normal stiffness of COPD lungs only
   2. B. Tension pneumothorax and decompress
   3. C. A failed bag that needs replacement
   4. D. Giving a fluid bolus and waiting
   Show answer

   Answer: B. Tension pneumothorax and decompress

   Fragile, hyperinflated COPD lungs can rupture under positive pressure, producing a tension pneumothorax even without trauma. Rising resistance, absent unilateral breath sounds, and arrest call for decompression of the affected side per protocol, plus slower ventilation. Assuming normal stiffness or equipment failure delays treatment.

4. Needle decompression improves blood pressure in a tension pneumothorax because it:

   1. A. Drains blood that is compressing the heart
   2. B. Re-expands the collapsed lung to restore oxygenation
   3. C. Relieves pressure that is blocking venous return
   4. D. Reduces afterload on the left ventricle
   Show answer

   Answer: C. Relieves pressure that is blocking venous return

   Releasing the trapped air lowers intrathoracic pressure so blood can return to the heart again. Blood compressing the heart describes tamponade, which needle decompression of the chest does not treat. Better oxygenation follows decompression but is not why the pressure recovers, and tension physiology is a problem of filling, not of left ventricular afterload.

5. You are preparing to decompress the chest of a 90-kg adult with a tension pneumothorax. The recommended catheter is a:

   1. A. 14-gauge, 3.25-inch (8-cm) catheter
   2. B. 18-gauge, 1-inch (2.5-cm) catheter
   3. C. 14-gauge, 1.25-inch (3-cm) catheter
   4. D. 22-gauge, 3.25-inch (8-cm) catheter
   Show answer

   Answer: A. 14-gauge, 3.25-inch (8-cm) catheter

   A large-bore catheter at least 3.25 inches (8 cm) long is needed to reach the pleural space in most adults; some systems use a 10-gauge. A standard 1.25-inch IV catheter often fails to penetrate the chest wall.

6. Short catheters often fail during needle decompression because:

   1. A. The pleura is too tough for a short needle to pierce
   2. B. A longer needle drains blood as well as air
   3. C. Short catheters slide into the mediastinum
   4. D. The chest wall is often thicker than the catheter
   Show answer

   Answer: D. The chest wall is often thicker than the catheter

   Studies show the chest wall at the second intercostal space is thicker than 5 cm in many adults, so a short catheter never reaches the pleural space. The pleura itself is thin and easily punctured once it is reached.

7. You are decompressing a 45-year-old at the second intercostal space, midclavicular line. The needle should be inserted:

   1. A. Straight in, over the top of the 3rd rib
   2. B. Straight in, just under the 2nd rib
   3. C. Angled medially, toward the sternum
   4. D. Angled upward, over the top of the 2nd rib
   Show answer

   Answer: A. Straight in, over the top of the 3rd rib

   The intercostal artery, vein, and nerve run along the lower edge of each rib, so the needle goes perpendicular to the skin just over the upper edge of the rib below. Going just under the 2nd rib aims straight at the neurovascular bundle.

8. Which finding best confirms a successful needle decompression?

   1. A. A flash of blood in the catheter hub
   2. B. A rush of air with improving vital signs
   3. C. Bubbling of the skin around the needle site
   4. D. A loss of breath sounds on that side
   Show answer

   Answer: B. A rush of air with improving vital signs

   Escaping air followed by better ventilation and perfusion confirms the tension was relieved. Blood in the hub suggests a hemothorax or a vessel puncture, not success.

9. A potential complication of needle decompression is:

   1. A. Tension pneumothorax developing in the opposite lung
   2. B. Bleeding into the opposite chest
   3. C. Laceration of the lung or intercostal vessels
   4. D. Delayed development of traumatic asphyxia
   Show answer

   Answer: C. Laceration of the lung or intercostal vessels

   The needle can lacerate the lung, intercostal vessels, or, if placed too medially or low, the heart and abdominal organs. A single needle on one side cannot injure the opposite lung or bleed into the other chest, and it does not compress the chest, so it does not cause traumatic asphyxia.

10. Ten minutes after a successful decompression, a patient again has falling BP and absent breath sounds on the same side. The most likely cause is that:

    1. A. The pneumothorax converted to a hemothorax
    2. B. The catheter has kinked or become occluded
    3. C. Tension formed on the opposite side instead
    4. D. Tamponade developed from the needle
    Show answer

    Answer: B. The catheter has kinked or become occluded

    Catheters often kink, clot, or dislodge, letting tension re-accumulate. Absent breath sounds returning on the same side do not fit tension on the opposite side or tamponade, which leaves breath sounds equal, and recurrence of the same signs points to the catheter.

11. You decompress the left chest of a large adult at the 2nd intercostal space, midclavicular line, with a 3.25-inch catheter. No air escapes, and he remains hypotensive with absent left breath sounds and JVD. The best next step is to:

    1. A. Leave it and wait for a chest tube in the ED
    2. B. Decompress the right chest instead of the left
    3. C. Give a fluid bolus and reassess in 10 minutes
    4. D. Decompress again at the left lateral site
    Show answer

    Answer: D. Decompress again at the left lateral site

    The most common reason for a failed decompression is a catheter that does not reach the pleural space, especially in large patients at the anterior site. Persistent tension signs call for a second attempt, and the 4th or 5th intercostal space just anterior to the midaxillary line has a thinner chest wall and lower failure rates. Waiting for a chest tube leaves an obstructive shock untreated. The findings are on the left, so decompressing the right chest treats the wrong side and can create a new pneumothorax. Fluid may support preload briefly, but it does not relieve the trapped air, and a 10-minute delay can end in arrest. (ATLS 10th ed.; TCCC Guidelines; Laan et al., Injury 2016.)

12. A 130-kg man has signs of tension pneumothorax, and you are concerned an anterior needle will not reach the pleura. A reasonable approach is to:

    1. A. Use the lateral site, where the wall is often thinner
    2. B. Use the sternal border, where the wall is the thinnest
    3. C. Use a shorter needle to avoid hitting the lung
    4. D. Avoid decompression because of his body size
    Show answer

    Answer: A. Use the lateral site, where the wall is often thinner

    The 4th or 5th intercostal space at the anterior axillary line often has a thinner chest wall than the anterior site, especially in large patients. The sternal border risks the internal mammary vessels and heart.

13. On the left side, keeping the needle at or lateral to the midclavicular line helps avoid the:

    1. A. Phrenic nerve and the diaphragm
    2. B. Esophagus and the thoracic duct
    3. C. Heart and internal mammary vessels
    4. D. Trachea and recurrent laryngeal nerve
    Show answer

    Answer: C. Heart and internal mammary vessels

    Medial placement risks hitting the heart or the internal mammary artery, which runs about 1 to 2 cm from the sternum. The phrenic nerve and diaphragm are not near the second intercostal space.

14. When using the lateral decompression site, placing the patient's arm above the head helps by:

    1. A. Increasing venous return to the heart
    2. B. Widening the rib spaces and exposing the site
    3. C. Pushing the collapsed lung away from the needle path
    4. D. Reducing pain from the needle insertion
    Show answer

    Answer: B. Widening the rib spaces and exposing the site

    Abducting the arm opens the intercostal spaces and moves the arm and axillary tissue out of the way. It does not move the lung, which is collapsed away from the chest wall by the tension anyway.

15. You are decompressing a 60-year-old at the lateral site. Inserting the needle below the fifth intercostal space risks injury to the:

    1. A. Subclavian artery or vein
    2. B. Brachial plexus nerves
    3. C. Liver, spleen, or diaphragm
    4. D. Internal mammary artery or vein
    Show answer

    Answer: C. Liver, spleen, or diaphragm

    The diaphragm can rise to the fifth intercostal space, so going lower can enter the abdomen. The subclavian vessels and brachial plexus lie near the clavicle, far above the lateral site.

16. If needle decompression is done on a patient who has no pneumothorax, it can:

    1. A. Create a new pneumothorax
    2. B. Cause tension in the other lung
    3. C. Cause immediate cardiac tamponade
    4. D. Do nothing, so it is harmless
    Show answer

    Answer: A. Create a new pneumothorax

    Puncturing a normal pleura lets air in and creates a pneumothorax, which is why decompression requires real signs of tension. It is an invasive procedure with real complications, not a harmless test.

17. You have just decompressed the right chest of a 30-year-old and heard a rush of air. You should now:

    1. A. Remove the catheter and tape gauze over it
    2. B. Pull the catheter out once air stops
    3. C. Connect the catheter to wall suction
    4. D. Leave the catheter in place and secure it
    Show answer

    Answer: D. Leave the catheter in place and secure it

    The needle is withdrawn, but the catheter stays in place and is secured so trapped air can keep escaping. Removing the catheter allows tension to re-accumulate.

18. During decompression, bright red blood flows from the catheter instead of air. This suggests:

    1. A. Successful relief of the tension
    2. B. A hemothorax or a lacerated vessel
    3. C. Correct placement within the lung
    4. D. Placement in the subcutaneous fat
    Show answer

    Answer: B. A hemothorax or a lacerated vessel

    Blood return means a hemothorax or an intercostal or internal mammary vessel injury, so the patient needs rapid transport for a chest tube or surgery. A successful decompression releases air, not blood.

19. After a crash, a patient has a BP of 70/40 mmHg, a heart rate of 136 beats/min, distended neck veins, and absent breath sounds on the left. The anterior decompression site should be the:

    1. A. Right 2nd intercostal space, midclavicular
    2. B. Left 2nd intercostal space, at the sternum
    3. C. Left 7th intercostal space, midaxillary
    4. D. Left 2nd intercostal space, midclavicular
    Show answer

    Answer: D. Left 2nd intercostal space, midclavicular

    The tension is on the side with absent breath sounds, so the left chest is decompressed at the 2nd intercostal space, midclavicular line. The tracheal deviation, if present, points away from the injured side, which leads some students to choose the wrong side.

20. Needle decompression for a suspected tension pneumothorax should be performed:

    1. A. As soon as tension is identified clinically
    2. B. After an x-ray confirms the diagnosis
    3. C. After arrival at the receiving trauma center
    4. D. After the SBP falls below 60 mmHg
    Show answer

    Answer: A. As soon as tension is identified clinically

    Tension pneumothorax is a clinical diagnosis, and waiting for imaging or deeper shock can lead to arrest. Delaying until the BP is very low wastes the window in which decompression works best.

21. When finding the lateral needle decompression site, the anterior axillary line can be located by following the:

    1. A. Center of the armpit straight down
    2. B. Back edge of the armpit down
    3. C. Front edge of the armpit downward
    4. D. Nipple line across to the side
    Show answer

    Answer: C. Front edge of the armpit downward

    The anterior axillary line runs down from the front fold of the axilla, formed by the lateral edge of the pectoralis major. The midaxillary line runs from the center of the armpit, and the posterior axillary line from the back fold. The nipple line marks roughly the 4th intercostal space level in men, not a vertical line.

22. In most adult men, the 4th or 5th intercostal space at the lateral site is at about the level of the:

    1. A. Clavicle
    2. B. Sternal angle
    3. C. Costal margin
    4. D. Nipple
    Show answer

    Answer: D. Nipple

    The nipple in men usually lies over the 4th intercostal space, making it a quick landmark for the lateral site. The clavicle and sternal angle mark the levels of the 1st and 2nd ribs, and the lateral costal margin lies well below the safe zone, where a needle could enter the abdomen.

23. Needle decompression converts a tension pneumothorax into a:

    1. A. Simple pneumothorax
    2. B. Massive hemothorax
    3. C. Pulmonary contusion
    4. D. Tension hemothorax
    Show answer

    Answer: A. Simple pneumothorax

    Venting the pressure leaves air in the pleural space without tension, and the patient still needs a chest tube at the hospital. Decompression does not cause a hemothorax unless a vessel is injured.

24. A 2-year-old has signs of a tension pneumothorax, and you will decompress at the 2nd intercostal space, midclavicular line. The most appropriate device is:

    1. A. A 10-gauge, 3.25-inch adult decompression needle
    2. B. A steel butterfly needle left in the chest
    3. C. An 18- to 20-gauge over-the-needle catheter
    4. D. A 24-gauge catheter to limit any lung injury
    Show answer

    Answer: C. An 18- to 20-gauge over-the-needle catheter

    A toddler's chest wall is only about 1 to 2 cm thick, so a standard 18- to 20-gauge over-the-needle IV catheter reaches the pleural space and vents the air while limiting injury to the lung, heart, and great vessels. A 10-gauge, 3.25-inch adult needle is two or more times longer than the chest wall is thick and risks puncturing the heart or great vessels. A steel butterfly needle left in place can lacerate the lung as it re-expands; the needle is withdrawn and only the soft catheter stays. A 24-gauge catheter is too narrow to vent air quickly and kinks easily. Sizes vary by protocol (some use 14- to 16-gauge in older children). (PALS 2020; Terboven et al. 2019; ATLS 10th ed.)

25. The anterior decompression site is preferred in a supine patient partly because:

    1. A. The heart lies directly beneath that point
    2. B. Air rises to the anterior chest when supine
    3. C. Blood pools there when a patient lies supine
    4. D. The diaphragm is highest at that point
    Show answer

    Answer: B. Air rises to the anterior chest when supine

    In a supine patient, free air collects at the highest point, the front of the chest, so an anterior needle reaches it. Blood pools posteriorly, which is why it is detected at the back and bases.