14 April 2008

Shadowing cardiac anesthesia

First thing this morning I was standing in the middle of an honest to god surgical code.

The day started at 7:15am in the neonatal intensive care unit (NICU) for closure of a persistent ductus. The ductus arteriosus is a fetal vessel that connects the pulmonary artery to the aorta. It generally closes in the first few days of life; failure to do so can cause congestive heart failure. During the surgery, the ductus was severed from the aorta before it had been clipped, leading to massive bleeding (3-4x the infant's blood volume); the infant had no blood pressure or pulse for several minutes.

Here I should make several observations. First, the vessels in question are extraordinarily small and fragile in a newborn; looking at them wrong can cause them to tear (this was not a case of surgical malpractice). Second, it is not the surgeon who leads the resuscitation, it's the anesthesiologist. The surgeon is, of course, trying to stop the bleeding, but the person pushing blood and drugs through and controlling the chaos is the anesthesiologist. Third, codes are messy. By the time the infant was back there were empty syringes littering the floor and all available surfaces. At least 6 people had streaks of blood on them from loading or handling the syringes (they don't have needles, they are screwed into the IVs), there were towels everywhere, and there were twice as many physicians present at the end than when it all started. It's all hands on deck and I now understand why the prep beforehand is so specific and organized: everything gets labeled, unpacked, laid out in order, etc.

We went straight from the NICU to the OR, where the patient was already prepped and under for a VSD patch and interrupted arch repair. A VSD is a ventricular septal defect (hole in the wall between the two large heart chambers) and it gets covered by a small graft. An interrupted arch is a little more complicated (a gap between the ascending and descending aorta) to fix (create the missing piece of aorta out of native and other tissue) and requires bypass and deep hypothermic circulatory arrest (DHCA). The body is cooled to 18 deg. C and all blood flow is stopped while the aorta is repaired. It turns out that shadowing the anesthesiologist gives you an unparalleled view of the surgical field so I was staring straight into the chest the whole time (photo, right) and watched the heart be cut open, closed, cannulated for bypass, decannulated, and an aorta fashioned, all in less than 3 hours.

At this point we took a break to get some juice and crackers on the way back to the NICU to check on the morning baby - doing well (needs a head ultrasound to check for bleeding). We then headed up the cardiac ICU (CICU) to debrief the interrupted arch parents and meet our afternoon case.

The afternoon case was a pacemaker placement due to heart block. The parents were of the most over-zealous and anal retentive type and both the parents and the patient were all very heavy. Seriously, this kid had 20kg on me. This time I was there from the beginning and so witnessed prep and induction of anesthesia (including intubation). A sternal approach was chosen, which quickly proved difficult due to the child's weight. The surgeon was quite literally up to his wrists in adipose (fat) tissue before he could visualize any heart muscle (the leads are placed on the heart, the generator (photo, left) is placed at the lower edge of the ribcage). The first lead went on the first try. The second lead took two tries, but, success! The surgeon then hollowed out about a 1/3 cup of adipose tissue to make a pocket for the generator, which is about the size of a post-it note.

What struck me about both surgeries is now physical it is (breathing through a mask and standing still in one place for hours turns out to be harder than it looks) and how many more stitches it takes. If you think of a laceration that might bring you into the ER, you will get one layer of stitches. Closing the chest requires at least three layers of sutures; closing takes a good 15 minutes (depending on the size of the incision). I also noticed all the surgeons wore these nifty magnifiers clipped onto their glasses (no one seems to wear contacts) and headlights even with the the bright overheads. Lastly, the temperature in the OR is largely determined by the procedure - in a DHCA case the OR is cooled to help with cooling and then heated to help with rewarming. Oh - and no one played music.

Photos from google images. More about patent ductus arteriosus. More about interrupted aortic arch.

1 comment:

Andrew said...

When I was younger, I asked my dad whether he'd get contacts, as they were becoming more common.

He said that he'd been saved by his glasses numerous times from getting stuff splashed in his eyes in the OR.