Friday, July 17, 2009
Max is normally a goofy, joyous Labrador, (are there any other kind?) always so happy to visit us for whatever reason-vaccines, ear infections, even getting neutered-you name it. He was always jumping and wiggly and just full of energy. But last week when he came in, things were markedly different for poor Max. He was struggling with something we all take for granted-Max couldn't breathe! Well, not without extreme effort on his part, any ways. He was panting, extending his neck, and just couldn't get comfortable. His owner reported that he couldn't lie down for any period of time and therefore hadn't slept in days. She and her family had actually been gone the week prior and Max had been looked after by a friend during that time. That friend noticed the problem developing towards the end of his stay, but couldn't pinpoint exactly when it started and couldn't tell us what might have triggered it. We were concerned that this could actually become a life-threatening issue, so we worked to get to the bottom of just what was causing the condition known medically as "dyspnea"-literally abnormal breaths.
Max didn't want to leave his owner's side, but we worked gently with him and encouraged him to allow us to work with him. Usually treats would have been welcome, but Max didn't want anything to do with food-it was all he could do just to get air in and out of his body. We had to figure out if this was because of an obstruction in his throat or airway, an infection in his lungs such as pneumonia, or if the dyspnea was secondary to some other condition. Pain and fear often cause our patients to stress so badly as to cause panting when we see them, but Max was having these breathing difficulties at home, too, where presumably he wasn't stressed. Pain was still possible, so we set out to find a possible source of that.
Max's blood work was perfectly normal-surprising since he hadn't eaten in so long. I expected at least some electrolyte abnormalities, but even they were just fine. We did find, though, that whenever we worked with him, Max became cyanotic-his tongue and gums became a distinctly blue or purple color due to the lack of oxygen traveling through those tissues, a very scary finding. We placed a mask over his nose and delivered oxygen to him-he didn't like the smell of that very much, but he evidently liked how it made him feel and he stopped resisting the mask pretty quickly when he realized it meant he could actually breathe with it around.
Next we put Max on the x-ray table and got some radiographs of his chest. It was difficult to get good films because he just couldn't lie in the positions required for very long at all. His blue tongue and distressed/panicked demeanor had us rush the process, but the diagnosis became evident despite the less than ideal positioning. Max had developed a pneumothorax.
Pneumothorax is free air in the space in the chest outside and around the lungs. It may result from trauma to the chest as when ribs become broken when animals are hit by a car, for example. We also see pnemothorax in patients who develop excessive pressure on their lungs, therby overinflating the lungs and rupturing the little alveoli or air sacs of the lungs. Underlying lung disease (asthma, chronic obstructive pulmonary disease, etc.) can also cause pneumothorax, again because the alveoli are damaged and air leaks out of them into the thorax. In some cases, we never do find out the cause of the pneumothorax-that is very frustrating because then we don't know if this will be something that will reoccur (and therefore how we might prevent it.) The problem with pneumothorax is that the air surrounding the lungs doesn’t allow the lungs to inflate normally, so dogs and cats with this condition can have difficulty breathing (the dyspnea we saw in Max), increased respiratory rate, exercise intolerance, chest pain, cyanosis, collapsed lungs, etc. If only a tiny bit of air gets inside the chest cavity, it can be resorbed and the pet can heal without medical help. If there is a lot of air in the chest cavity, however, it must be removed medically. If severe cases are left untreated, or it is progressive as happens with big holes in the chest, the pneumothorax can be fatal.
Max's chest was FULL of air-this was a pretty severe case of pneumothorax, but it did not appear to be progressing rapidly. If it had, he likely wouldn't have still been alive. We searched teh x-rays to find a cause for the free air in his chest cavity. There were no obvious broken bones or other evidence of trauma. We certainly would have hoped his dog-sitters would have told us if he had been hit by a car or had experienced some other massive trauma or had been exposed to any toxins or the like. His blood work hadn't indicated any raging infections as a possible cause, and we didn't see this on the radiographs, either. We were facing an unknown cause of his condition, but at least we knew how to help him. We had to take the air surrounding his lungs out of his chest, and we could do this with a long needle and a great big syringe. Some patients require the palcement of an indwelling valved chest tube, allowing for the continued evacuation of the free air while the patient's body heals from whatever condition caused the air leakage or production in the first place. My biggest concern was that after evacuating Max's chest of all that free air, what would prevent it from coming right back? We just would have to wait and see and hope that it was a one time thing and that his otherwise young and healthy body would be able to heal.
The process of inserting a needle into the chest in order to aspirate and remove the free air is called thoracocentesis. It is important that anytime you insert a needle into the chest cavity that you don't inadvertantly introduce bacteria into it, so we did a surgical prep of Max's skin over his rib cage on both sides of his chest. This involved clipping the hair off and scrubbing the skin with an antimicrobial solution. We inserted a needle into his chest, attached some tubing and a syringe, and pulled some air off his chest-and continued to do this over and over and over for well over an hour. we finally got negative pressure on the syringe after almost 10,000 mls of free air was drawn off the left side of his chest and another 1000 mls was taken off his right side. I suspect the two sides were communicating with each other and the "little" extra taken off the second side was just found in a pocket there, but regardless, it was an impressive volume-over 2 1/2 gallons of air where it shouldn't have been!
It was pretty darned cool to watch Max during his thoracocentesis procedure. Initially, it was very difficult for him to sit still for us; there just wasn't any position where he was comfortable and he became cyanotic very frequently from stuggling/panicking. He required oxygen by the face mask, but we had to just keep forging ahead. As more and more air was removed, Max became visibly more comfortable. At first, we noticed he was simply breathing through his nose; he was no longer open-mouthed breathing or panting. Then he became more and more relaxed to the point he rested his head in his nurse's lap, sighing deeply, and even shutting his eyes a bit. He was exhausted, the poor thing, and relieving the air gave him the freedom to stop struggling and just rest. We all felt so good for him.
We never did find out the cause of Max's pneumothorax, but he was lucky. We sent him home and over night and through the next day, there was no evidence that the pneumothorax was returning. We never did have to place a chest tube, but we did put him on some antibiotics and some antiinflammatory medications. We had Max come in that next day and we listened to his chest, but you could just tell by looking at his face and reading his demeanor that he was back to his happy, rested self-no longer preoccupied with where his next breath was going to come from. His owners were please and very relieved, and it looked like they were able to finally get some sleep, too. Breathing is a good thing.