Week #3: Brains, babies and bowels

This week began with my very own MRI scan! But don’t worry! I didn’t hurt myself or anything, but rather Dr. Prince opened up the MRI facility for us to learn about the machine. My brain looks healthy and contrary to the belief of some of my peers (not naming any names), I also appear to have a heart (although the image was a bit fuzzy). At the bare minimum, I have a large inferior vena cava (yellow arrow) and in the left image below you can see my kidneys, liver (left) and spleen (right). Not everything was fun and games- one of Dr. Prince’s students scanned my liver in order to optimize a new imaging protocol. My liver and I were happy to be of service.

I am particularly fascinated with the physics behind MRI technology and with how mathematics (Fourier analysis) is used to reconstruct an image from the raw data (k space) containing frequency, phase and signal intensity information. When the body’s water-containing tissues are exposed to an oscillating magnetic field at a specific resonant frequency, excited hydrogen atoms emit radio waves which can be detected. MRI is often the most powerful imaging modality for many applications. 

In addition to brain and body scans, my week was also filled with many interactions with babies, in both the neonatal intensive care unit (NICU) and pediatric intensive care unit (PICU).  In the NICU, I was impressed with how many neonates Dr. Yap’s group evaluated during rounds: ~20 babies! The NICU treats newborns as small as 400 grams (less than one pound) as premature as x22 weeks (gestational age). Since the lungs are one of the last organs to develop, many of the babies need respiratory support and surfactant treatment in order to decrease surface tension and keep the lungs from collapsing. Neonatal hypoglycemia is another common problem that must be treated in order to avoid brain damage. I attended a journal club discussion of “the sugar baby study,” a recent publication assessing whether treatment with dextrose gel was more effective than feeding alone for reversal of neonatal hypoglycemia in at-risk babies. While the study suggested advantages of using the dextrose, it was not without biases and limitations (e.g. failure of the study to reflect the overall population) and the journal club members were reluctant to change their NICU feeding protocol. One thing was clear: there is a need for less invasive, continuous glucose monitoring; otherwise, babies get continuously “sticked,” adding to the many painful procedures already experienced by premature babies.  

After experiencing the NICU, it was time to graduate to the pediatric ICU (PICU) with Dr. Deyin Hsing who was very kind and informative. Two patients stood out during my time there. The first was a girl with Maple Syrup Urine Disease, a disease named for the sweet-smelling urine that contains the lactone, Sotolon which according to Wikipedia may be responsible for the “mysterious maple syrup smell that has occasionally wafted over Manhattan since 2005.” I just thought that smell was rotting garbage. Regardless, this disease particularly affects the Mennonite population and is caused by an inherited mutation in the branched chain alpha keto dehydrogenase complex which is responsible for breaking down the amino acids leucine, isoleucine and valine. It is typically very treatable with dietary modifications, but this patient had a bone marrow transplant and inadequate nutrition. She started catabolizing her own muscle tissue and releasing the amino acids which could not be processed, leading to toxicity in the kidneys and brain. Dr. Hsing informed me that a lab test to detect toxic amino acid levels in blood plasma took days to analyze. Together we explored a solution, utilizing existing data to predict toxicity levels using an osmolal gap concentration calculation (since test for blood osmolality is pretty rapid). Unfortunately, the contribution of amino acid build-up to the serum osmolality was a few orders of magnitude too small to be detectable. Perhaps a solution to this problem can be engineered (project idea???).  

Later in the afternoon, I observed the stabilization of a one-year-old tetralogy of fallot patient following pulmonary valve repair, triscupid repair and PA-plasty. The IV was not woking and a direct line needed to be installed through the femoral. The patient was also “juicy,” meaning that there was a lot of residual bleeding which drained from a set of chest tubes into a Teleflex chest drainage system. I noticed two shortcomings of this system: 1) judicious manual clearing of the (clotting) chest tubes was needed throughout the procedure and 2) a manual calculation of blood loss per hour was needed. While a cost-benefit analysis would be necessary, Dr. Hsing said that a digital readout would beneficial and more precise if available. It took all afternoon and most of the evening to stabilize the patient, but his blood pressure and respiratory function greatly improved by the following day.

To finish off the week, I shadowed the Chair of Surgery, Dr. Fabrizio Michelassi in the OR. The coolest part of this was observing a right hemi-colectomy and having the opportunity to feel the noticeable (order of magnitude) difference in stiffness between bowel tissue and tumor. As someone who studies cellular mechanics, it was incredible to experience this first-hand and to verify what I had learned about cancer biology.