When you can”t ventilate through an endotracheal tube, we all think esophageal intubation. But could it be severe bronchospasm? Recognizing severe bronchospasm and deciding how to proceed depends on the patient and the circumstances. It’s not always easy.
The Case
The two-month-old baby, born very premature, was only now about the size of a newborn. Weighing in at 4 kg, my thumb dwarfed his tiny hand as I watched my partner anesthesiologist, Dr. X, prepare to induce anesthesia in preparation for inguinal hernia repair. The repair was somewhat urgent because the hernia had almost incarcerated recently. They had manually reduced it two days before.
Premies who spend their first month on a ventilator often suffer some lung damage and this one was no different. The infant, still residing in our hospital nursery, had been on medication for bronchospasm following extubation several days before. He had not needed recent treatment. I stood by during the induction as “an extra pair of hands” due to the baby’s complicated history,
Dr X chose IV induction with propofol and norcuron, rather than risk hypotension with a deep inhalational intubation in a baby so small. She then intubated the baby with a 3.0 tube. I listened for breath sounds — and heard nothing. The chest didn’t rise and there were no breath sounds or end tidal CO₂. Compliance was poor with high peak pressures. Oxygen saturation started to drop. Classic signs of an esophageal intubation.
Extubation #1
Despite observing the tube pass through what appeared to be the vocal cords, Dr X. quickly removed it. At first, manual ventilation with the mask was difficult. Ventilation improved quite a bit with insertion of an oral airway and increasing the concentration of sevoforane.
Intubation/Extubation #2
After the baby’s oxygen saturation reached 100%, Dr. X reintubated. Once again, we observed no chest rise, poor compliance, absent breath sounds, and no end tidal CO2. Visualization confirmed tube placement through the cords, but since ventilation was unsuccessful, she removed the tube again. It’s too easy to miss an esophageal intubation and she erred on the side of caution in case she was wrong.
An infant has little respiratory reserve and will become hypoxic quickly (see 10 Common Pediatric Airway Problems — And Their Solutions). This infant had been easy to ventilate with a mask at the beginning of the case. Therefore, even though Dr X believed she had seen the tube pass through the cords, she decided to remove the tube, ventilate, stabilize and then reintubate.
Severe Bronchospasm Detected
This time I heard a brief, faint wheeze at the end of one of the more forceful manual mask ventilation attempts. Bronchospasm triggered by the endotracheal tube had led to complete airway closure. No air movement meant no breath sounds and no chest wall motion.
Had this been an adult, we undoubtedly would have measured some end tidal CO2 on the capnograph. This 4 kg baby, with a tidal volume far below the usual 40 ml, was unable to exhale enough CO2 for measurement.
Improvising An Aerochamber
Oxygen saturation levels dropped without effective ventilation. I grabbed the albuterol inhaler from the emergency kit and improvised an aerochamber by disconnecting the circuit and spraying three quick puffs through the mask’s top hole. Meanwhile, Dr X held the mask against the baby’s face to maintain a tight seal. We reconnected the circuit promptly to keep the albuterol from escaping before giving a few slow deep breaths.
The makeshift aerochamber delivered bronchodilator to the lungs, breaking the bronchospasm. Musical wheezes became audible on both sides of the chest.
Go No Go
Anesthesia is filled with go-no-go decisions. Once we had diagnosed severe bronchospasm, we needed to decide whether to cancel or proceed. Our surgeon argued against cancelling the surgery. Although the baby currently did not have a bowel obstruction, incarceration had almost occurred. Surgery would be quick and would minimally effect the baby’s respiratory status afterward. We agreed that if the bronchospasm resolved we would proceed.
Oxygen saturation returned to 100%. Dr X intubated the baby for the third time. I heard mild wheezing on auscultation. The bronchospasm resolved quickly with further treatment and deepening the sevoforane. The baby stabilized and surgery proceeded. Dr. X administered IV dexamethasone 0.6 mg/kg IV out of concern for development of potential post extubation croup from the multiple intubations and visualizations. The baby did fine without complications.
In hindsight, pretreating with a bronchodilator closer to the time of induction, and performing more of an inhalational induction before intubation at the outset, might have minimized bronchospasm risk.
Discussion and Differential
When you can’t ventilate through an endotracheal tube the potential reasons include:
- esophageal intubation
- obstruction outside the endotracheal tube
- obstruction inside the endotracheal tube
- breathing circuit malfunction
While you are working through your differential diagnosis go to 100% oxygen. Call for help early. Ventilate by hand. Stop any surgical stimulation. Check tube position, clear secretions, and eliminate circuit occlusion. Always consider allergy or anaphylaxis.
Esophageal Intubation
The most common explanation of being unable to hear breath sounds after intubation is an esophageal intubation. When all signs pointed to esophageal intubation the anesthesiologist made the logical choice to pull out the endotracheal tube, mask ventilate the patient and repeat the intubation.
After a second suspected esophageal intubation, the anesthesiologist repeated laryngoscopy to confirm tube placement through the vocal cords. Despite this, she still couldn’t ventilate the baby. After the second intubation Dr X had several choices:
- Leave the tube in, keep trying to ventilate and troubleshoot
- Have someone else check the position of the tube
- Extubate, ventilate with a mask, and troubleshoot
- Cancel the surgery, wake the baby and come back another day
Anatomical landmarks for intubation are not always obvious. The esophagus is close to the trachea. The infant trachea is short. It’s very easy for the tube to slip into the esophagus with small movements of the head and neck. In this sort of emergency, when time is short for trouble shooting and anatomical landmarks may not be clear you should always question whether the tube is still in the trachea. In this case there were no chest wall expansion, breath sounds, or end tidal CO2. Dr. X erred on the side of caution, even though she thought she saw the tube passing through the cords after the second intubation.
For a case of near miss esophageal intubation see: Unplanned Extubation: What Goes In Can Easily Come Out
Obstruction Inside the Endotracheal Tube
Endotracheal tubes can become plugged or kinked. Small bore pediatric tubes can easily kink inside the mouth. Try suctioning through the tube. Failure to pass an appropriately sized suction catheter means obstruction until proven otherwise. I have seen endotracheal tubes obstructed with organized blood clot and with dried secretions which prevented ventilating through a properly placed endotracheal tube. See: A Case of Endotracheal Tube Obstruction
Always have the appropriately sized suction catheters available in the room. You don’t have to open them, but you do have to have them.
Obstruction Below the Endotracheal Tube Tip
Is something preventing air from entering the patient’s lungs? Consider:
- bronchospasm
- obstructing foreign body or mucous plug beyond the tip of the ETT
- pneumothorax
- severe pneumonia
- aspiration
In this case severe bronchospasm initially prevented all attempts at ventilation. I have seen bilateral tension pneumothorax mimic esophageal intubation because breath sounds were poorly heard on both sides of the chest and ventilation was impossible. See: Bilateral Tension Pneumothorax: Harder To Diagnose
Malfunction in the Breathing Circuit
If the tube is in the trachea, it’s not plugged or kinked, and the patient’s lungs are okay is the problem you breathing circuit? Your breathing circuit and anesthesia machine can both malfunction. Can you ventilate the patient with an ambu bag? If you can then the problem is in the circuit, not the tube or the patient.
I once had a manual ventilation bag with the pop-off valve incorrectly assembled. It looked like it was working but I couldn’t ventilate at all. Another time the mother board on a new electronic anesthesia machine we were trialing failed in the middle of surgery on a baby. I couldn’t ventilate using the machine circuit because an internal switch had been thrown — but I could ventilate easily with an ambu bag. In that case I maintained anesthesia using propofol until my team swapped out the trial machine for a trusty old-fashioned one.
Circuit malfunction is rare, but don’t ignore the possibility. Always have an ambu-type bag immediately available.
Laryngospasm
In the event the patient is not intubated, always consider laryngospasm. Laryngospasm can be severe enough to prevent all ventilation. For a discussion of laryngospasm see: Laryngospasm is a Life-Threatening Emergency
Bronchospasm
Bronchospasm may happen on its own or as part of severe reactions such as anaphylaxis during general anesthesia. It is marked by symptoms like longer exhalation, wheezing, and higher airway pressures while ventilating the patient. If not treated, it can lead to hypoxia, low blood pressure, and increased risk of sickness or death. Quick evaluation and treatment are vital, with ongoing care focused on addressing the root cause.
Bronchospasm can occur for a wide variety of reasons, including:
- history of asthma, COPD, or other bronchospastic diagnoses
- upper or lower respiratory infection
- allergy and anaphylaxis
- histamine release from drug exposure (for example morphine or atracurium which can occur without allergic reaction)
- beta blocker administration
- airway soiling or aspiration
- tactile stimulus such as an endotracheal tube in a predisposed patient
The severity and timing of this baby’s bronchospasm was unusual and initially led to a wrong diagnosis of esophageal intubation. Always remember that intubation can not only cause bronchospasm, it can make pre-existing bronchospasm worse. And it can be severe enough to totally prevent ventilation. Be prepared to treat it. Having the means of giving inhaled bronchodilator immediately available is smart and can be lifesaving.
Treating severe bronchospasm itself is beyond the scope of this article. For more information see:
It can be difficult to recognize severe bronchospasm. Be alert.
