Inside the dogs open chest…

Fluid therapy by cannula

I spend hours upon hours reading, studying, visualising and learning from what seems like an endless stream of knowledge. Some of it is stuff I know I will never use but must learn (such as slaughter inspection), then there is stuff that will be used commonly (such as dog vaccinations), and finally the stuff that is really interesting that I won’t use unless I end up a specialist (such as heart bypass protocols).

Now whilst a little more common in the UK, a thoracotomy is not really common here – there have only been 2 in the past 18 months and one of these was traumatic performed by a dog attack. A thoracotomy is where the chest is opened – whether that is for heart or lung surgery or something completely different. This was the first time I have assisted on a thoracotomy where it was intentional…

The case today was different; a dog had got a foreign body stuck in its esophagus. We originally tried endoscopy via the mouth as a minimally invasive approach, whilst we could visualise this foreign object in the esophagus, it was too large to be able to grab or move onwards into the stomach. Unfortunately also when an object has been in place for a while it can also weaken the wall of the esophagus around it so moving it can cause rupture so we have to be very cautious around this as well.

So we went into surgery as an emergency to remove this obstruction from the esophagus. Unfortunately the esophagus mostly lies within the thorax (chest) – it enters the stomach just a few cm’s beyond the diaphragm. This meant that to get to the foreign body meant opening the chest.

Opening the chest is not like it is on TV medical drama’s – there are numerous complications that can occur – and its technical surgery to stop the lungs inflating on the side of the surgery so that there is space to work. Also you have to open in the correct space between ribs to give you access to where you need to be. We open the tissue layers above the space we want to use to gain access to the chest, and then open the space between the ribs.

The pink of the lungs inflating is visible before we deflate them on this side to give us the space to operate. This space is still relatively small, it’s only a small dog, and the ribs will not stretch that far apart. We bring in the rib spreaders – this gives us maybe space 4cm wide to work in, though it sounds like a lot the esophagus is in the center of the chest, maybe 7cm deep. Think about having to operate on the bottom of an empty tin from the top… This is where suturing becomes more fun and demanding, or even dissection, the tip of the scalpel has to be used whilst holding the end of the handle instead of the normal curve of the blade.

Looking up the chest where the lungs are deflated I can see the beating heart – however it is the esophagus that we are interested in – we can see the bulge of the esophagus where the foreign body is. Everything is moving though, and barely seems to stay still.

We use stay sutures to hold the esophagus as close to the wall as we can whilst making an incision into it – opening the muscular layer, and the inner mucosa. We delicately manipulate the foreign object (which looks like a chicken head & neck) from the esophagus. It is larger than we expected so we have to make the incision longer to accommodate it, and then it is out. Time to close – we did this in two separate layers – one for the mucosa and then the muscular layer around this.

One of the tricky things about thoracotomy is getting the chest closed and the lung re-inflated and breathing again. A chest drain can help with this so this is placed. We then place all our sutures into the chest wall around the ribs either side and then let the lungs inflate as we close the wall together before tying these sutures. The wall muscles and skin is then closed.

We remove the excess remaining air through the chest drain to ensure the lung can inflate fully. And then move the dog over to recovery which was surprisingly uneventful.

This has taken maybe 3 hours in total, yet my study around the chest is many hundreds of hours. I know where things are – the vagus nerve runs along the esophagus which is essential we do not damage as it controls so much of the body – the heart, abdomen, throat, swallowing. The major vessels of the aorta and vena cava also run close to the esophagus here so we have to be precise. It’s also important how we open the intercostal space so we do not damage the nerve and vessels that run along the rib. The way the respiration of the animal is compromised when the chest is opened is something that needs to be dealt with – we used a ventilator to keep the patient breathing during surgery.

Now with my latest surgery high finally being beaten by tiredness I am going sleep for the new day tomorrow.