Saturday, March 25, 2017
Bedside (Point of Care) Ultrasound of the Lung--So Good
I've blogged on and on about my undying love for ultrasound at the bedside as a part of my physical exam. It keeps being powerful. It saves peoples' lives. It keeps me from making stupid mistakes. I am eternally grateful.
This week it helped with the usual things--hearts and bellies and bladders and lumps and bumps. I was able to tell patients what was going well and not so well, in real time, and show them pictures.
But ultrasound of the lung needs a little advertisement. Ultrasonographers and radiologists are terrific at imaging the internal organs, even those of tiny babies. Cardiologists and echocardiogram technicians are amazing in their ability to image the heart and describe its innermost workings. Although I leverage my ultrasound abilities by using my other exam and history taking skills, I do not have the extensive training in imaging that these people do. But in the US, only clinicians such as myself look at the lungs. Radiologists may look at the bases of the lungs for fluid, in order to more accurately sample or drain that fluid. But they don't look for pneumonia or pneumothorax (popped lung) or make predictions about the quality of pleural fluid based on what it looks like. So there is no question that the lung belongs to us, the non-radiologists.
This is a collection of 5 patients whose lung ultrasounds made an important difference in their care:
1. An ancient man, whose esophagus was completely non-functional, had continued to eat food despite the sneaking suspicion that it wasn't going down all the way. When he finally became too uncomfortable, his esophagus was packed with several meals and he was unable to swallow even his own saliva. The obstruction was relieved, but he then had a fever. Ultrasound of the lung showed the aspiration pneumonia that I suspected and I was able to decide on the appropriate treatment. He was so out of it after his procedure that he probably would not have been able to take a deep breath and the chest x-ray would probably have been inconclusive, and the ability to diagnose his condition with ultrasound meant that he did not need to be disturbed.
2. A woman arrived with a low oxygen level, kidney dysfunction and a bit of a wheeze. She had an elevated white blood cell count but no fever. Her ultrasound showed normal appearing kidneys and a left sided pneumonia. She responded well to antibiotics for community acquired pneumonia with increasing strength, no further need for oxygen and normalization of kidney function.
3. An octogenarian with endstage lung disease was short of breath a day after being started on bipap (bilateral positive airway pressure via mask). The nurses were unable to hear breath sounds in one of his lungs and were worried he might have a pneumothorax. A very quick check for lung sliding with my pocket ultrasound machine (the two layers of pleura moving against each other) proved to me, the nurse and the respiratory therapist that his problem was worsening airway obstruction rather than a pneumothorax. The patient was also happy with the attention. He was better by the next day.
4. A previously healthy young man came in with shortness of breath and a test positive for influenza. His ultrasound showed pretty significant pneumonia, due entirely to his influenza. It was clear that he needed to be hospitalized rather than sent home. His chest x-ray was equivocal. Ultrasound is definitely more sensitive for pneumonia than a plain chest radiograph, though determining the meaning of a wet area or consolidation depends on paying attention to other clinical information.
5. A patient hospitalized for another problem began to have increasing leg swelling and a slightly lower oxygen level. Ultrasound showed pleural fluid collections and he responded well to an increase in his medication for heart failure. Emergency decompensation averted. What I knew about the patient as well as the quality of the pleural fluid on ultrasound made it clear that this was related to his fluid status and not infection.
Radiologists do not look at the lung with ultrasound because normal lung looks like nothing, just gray fuzz with some horizontal stripes.This is because lung is filled with air like a slab of micro-bubble wrap and does not transmit sound well. They also have other imaging techniques, such as x-ray and CT scan which give them better static pictures. I'm sure they could develop advanced techniques for detecting pathology using ultrasound if they set their minds to it, but for now it belongs to us.