Interesting case - Possible iatrogenic air embolus

[USCDiver]

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Patient is a 35yo male getting aggressive hydration (250cc/hr) as an adjuct to chemotherapy through a tunneled Hickman CVL. During the night while lying in left lateral decubitus position, the pump alarms for air in the line. He astutely pushes the restart button and goes back to sleep.

About an hour later, the pump alarms again for air in the line, and also that the bag needs to be changed. Nurse comes to the room, changes the bag and restarts the pump. It immediately alarms for air in the line so she takes the line out of the pump chamber and reprimes it. No obvious damage to the line or air leaks.

Patient remains in L lateral decubitus position for another few minutes before rolling on his back. Within a few seconds he has severe coughing attack, worse with deep breath, better sitting up. No chest pain, no subjective dyspnea. Just a persistent dry cough. Vitals are unchanged, no tachypnea, tachycardia or hypoxia. Lung sounds are clear and no peripheral edema. Symptoms improve quickly and completely resolve in about 20 min.

You know all those small air bubbles that we all see running in IV tubing but never worry about because they are small enough to be reabsorbed in the pulmonary vasculature without causing any symptoms? I suspect that because the patient was lying in left lateral decubitus position that several of those small bubbles became trapped in his R atrium and coalesced into a large enough bubble to cause a brief symptomatic air embolus.

Thoughts?

 

[JacobMcCandles]

I have always been told that it takes a large embolus (~100cc) to be symptomatic. Maybe by symptomatic, they meant fatal. Either way, I've yet to see one in real life.

 

[USCDiver]

Yeah, it definitely wasn't a huge volume of air, but who know how much it takes to make you cough. I would think 100cc would be enough to not only cause symptoms, but also some sort of hemodynamic changes.

I just couldn't think what else could cause such rapid symptom onset and resolution without any changes in vitals. Doubt pulmonary edema or pneumonia. He had gotten Malphalan about 12 hours prior and I was able to find a couple of case reports of pneumonitis, but not with a single dose. I suppose the patient is at risk for PE, sedentary with active malignancy, but I would not expect that type of symptomatology with a PE and no other vital sign abnormalities.

 

[TooMuchResearch]

I have always been told that it takes a large embolus (~100cc) to be symptomatic. Maybe by symptomatic, they meant fatal. Either way, I've yet to see one in real life.

I was taught 100 mL for possible fatal air embolus, but 10 mL in pts with PFO.

 

[CATrtb]

I've seen a 100ml air embolus given to a young man during a ct scan (contrast syringe on the injector was an empty used one). He remained asymptomatic, but you could see the giant air bubble in his heart on the images.

 

[Birdstrike]

Patient is a 35yo male getting aggressive hydration (250cc/hr) as an adjuct to chemotherapy through a tunneled Hickman CVL. During the night while lying in left lateral decubitus position, the pump alarms for air in the line. He astutely pushes the restart button and goes back to sleep.

About an hour later, the pump alarms again for air in the line, and also that the bag needs to be changed. Nurse comes to the room, changes the bag and restarts the pump. It immediately alarms for air in the line so she takes the line out of the pump chamber and reprimes it. No obvious damage to the line or air leaks.

Patient remains in L lateral decubitus position for another few minutes before rolling on his back. Within a few seconds he has severe coughing attack, worse with deep breath, better sitting up. No chest pain, no subjective dyspnea. Just a persistent dry cough. Vitals are unchanged, no tachypnea, tachycardia or hypoxia. Lung sounds are clear and no peripheral edema. Symptoms improve quickly and completely resolve in about 20 min.

You know all those small air bubbles that we all see running in IV tubing but never worry about because they are small enough to be reabsorbed in the pulmonary vasculature without causing any symptoms? I suspect that because the patient was lying in left lateral decubitus position that several of those small bubbles became trapped in his R atrium and coalesced into a large enough bubble to cause a brief symptomatic air embolus.

Thoughts?

Interesting. Could be. I guess there's now way you'll ever know.

 

[Rendar5]

...or maybe he just accidentally aspirated a bit of saliva, hate it when stuff goes down the wrong pipe.

 

[glorfindel]

Interesting... very interesting!

I'm inclined to think not, and the reasons are

-cough as the only symptom? If it were an air embolus big enough to be symptomatic, I'd guess that there would be more sx than just cough. An embolus is an embolus whether it's made of air, fat, or clot, and I'd guess that a symptomatic embolus would cause pain, hypoxia, tachycardia, hypotension, etc. and not just cough.

-many other possible explanations for coughing spell. The pretest probability, as they say, is very low. It's anecdotal, but I've had many fits of coughing in my life, yes I have. I doubt any of them were caused by an air embolus. (On the other hand, I can't recall a coughing episode I've had while hooked up to a CVL and the pump is alarming for air in the line...)

Good post

+1

ps: Ask the guy if he's had coughing spells before in HIS life, when HE wasn't hooked up to a line like you described. I'd bet dollars to donuts the answer is "yes."

 

[USCDiver]

He has not previously had anything similar to the spell that he described while hooked up to the IV pump, although the subsequent morning, after sleeping without fluids running, he had similar cough with deep breath. I am now less concerned about air embolus. This is probably some atelectasis from lying in bed too much. Incentive spirometry to the rescue!