Thats a Wrap!

After 24 hours in the incubator, the plates definitely had growth, but there were no distinct differences. 

Before incubation: 

After: 

As you can see, the bacterial growth on all three plates look very similar. For this reason, I concluded that the use of neither the braided vicryl nor monocryl led to increased bacterial presence, and bacterial adherence to both sutures is about the same. This conclusion is not accurate for many reasons. For one, the experiment was not conducted in a sterile environment with sterile tools and surfaces. Also, the sutures were placed in pork which was left out for five days so it is only natural that bacteria associated with rotting meat was apparent. 

Since this will be my last post, I would like to thank all of you for keeping up with my posts these last 12 weeks. I will be presenting my project on May 6th at BASIS Phoenix if anyone is interested in attending!

Week 11: Plating the Sutures

Yesterday, I plated the sutures from the pork meat and put them in the incubator. For the control, I swabbed the meat and rolled it onto the agar. The smell of five days old rotting meat was definitely my favorite part...

Anyways, here is a photo of the plated sutures and control.



Today, I will take the plates out of the incubator and analyze the bacterial growth.

Thoracoscopic Pericardial Window

This week in the OR, I watched a few different surgeries, but I want to focus on the thoracoscopy.

Thoracoscopy

The patient presented with pericardial effusion which is an abnormal build up of fluid around the heart (pictured below).

In order to relieve the pressure and drain the fluid, Dr. Patel performed a thoracoscopy to create a pericardial window (a hole in the pericardium). A drain was placed in the pericardial window to remove excess fluid after surgery. Talcum power was then sprayed around the lungs to prevent this problem from returning. The powder induces an inflammatory reaction which causes the lungs to stick to the inner surface of the chest, leaving no room for fluid build up.

Next week, I will plate the sutures for my suture project and post about the results!

Week 10: Getting Started

I started my suture project on Thursday! After three trips to three different grocery stores, I figured it is nearly impossible to find pork belly anywhere near me, so I improvised with sliced pork with a thick layer of fat on top. It was important to suture something similar to human skin and the layer of muscle underneath, so this made do. To my surprise, I found the layer of fat hard to pass a needle through, so it definitely did a good job simulating skin. 

To start, I cut the pork into three pieces and made a cut in the middle of each. With each suture, I closed the incisions I made using an intradermal suturing technique. I must say, as my first time suturing pork, I am proud of how it turned out...!  

Vicryl (left), Monocryl (middle), and Control (right)

All I have to do now is wait for two more days to remove the sutures and plate them!

Previous Research

When deciding to pursue this new and revised project, I found studies and research papers regarding the instance of infection for monofilament and braided sutures. I will reference these papers, namely the following, during my experiment.

The scientific article that really caught my attention is titled "Bacterial Adherence to Surgical Sutures" (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345192/pdf/annsurg00209-0047.pdf). This article considers and studies that bacterial adherence patterns on braided and monofilament sutures. In the abstract, it states that "nylon bound the least bacteria while bacterial adherence to braided sutures was five to eight folds higher" (they used nylon as an example because it is also a monofilament suture). This is what caught my attention right away, because in cardiac surgery, both monocryl and braided vicryl are commonly used to close the skin. Why would we use braided sutures to close the skin when bacteria adhere to them more frequently and increase the chance of infection? This is what I hope to explore in the last couple of weeks of our research projects. Stay tuned!

Week 9: Vicryl Sutures

Since I changed a few things for my suture project, I am going to post this week about certain aspects of my new idea. In this post, I will talk a bit about Monofilament Vicryl (Monocryl) and Braided Vicryl sutures.

Sutures I will used for my project

I will be using size 4-0 in the Monocryl sutures and size 3-0 in Braided Vicryl because these are the two most common types of sutures used for skin closure. Generally, size 3-0 and 4-0 are the preferable sizes for skin closure because they can withstand the amount of tension put on the skin. Below is a helpful guide to understanding suture sizes:

4-0 Monocryl is a monofilament suture, which means it may be tougher to knot and have a lower knot holding security, unlike 3-0 Braided Vicryl. However, it incites a very low tissue reaction and is thought to harbor less bacteria, so it is great for skin closure (lowers risk of skin irritation, and thus infection). 

Both are absorbable sutures which means they will "dissolve" in the skin as the wound heals. 3-0 Braided will break down anytime between 56-70 days while 4-0 Monocryl will take around 90-120 days. The skin will need a couple of months to thicken and heal completely, but by the time the sutures break down, it will be strong enough to remain closed and resist tearing. 

In my experiment, I will do an intradermal stitch which is used to close the skin after surgery. This type of stitch secures the edges of the wound (chosen mostly for cosmetic and healing purposes).

Intradermal stitch

Tricuspid Valvectomy

This week I watched a Tricuspid Valvectomy. The patient was septic (bacteria in the bloodstream), and had Infective Endocarditis, Hepatitis C, and MRSA. Also as an intravenous drug addict, the patient was prone to these serious complications. Infective Endocarditis is caused by a bacterial infection in the heart and can result in inflammation of the valves, heart failure, and abscesses.



The patient had an abscess near the tricuspid valve and the swelling was preventing it from keeping blood from rushing backwards in the heart. Dr. Patel removed the abscess and the replaced the valve. The patient was given antibiotics after surgery.

Week 8: Suture Project

After a couple hours of research and emailing my advisor, I finally have a solid idea for my suture project. I decided to stick to my original proposal, but I made a few changes to eliminate major problems and flaws in the experiment. 

In this experiment, I will focus on the infection rate of Braided and Monofilament Vicryl sutures used to close the layers of fat and skin over the sternum after open heart surgery. I decided to narrow the list of sutures down to Braided and Monofilament Vicryl because these are designed and most commonly used for skin closure. I have read a few published articles online that state that bacteria adhere and grow on braided sutures more frequently than monofilament sutures. I will conduct my own experiment to see this for myself. Instead of using chicken feet, I will sew the sutures into pork belly because it closely resembles the properties of human skin (resistance, thickness, and texture). After five days, I will plate the sutures and observe bacterial growth. I will also swab pork belly without the sutures in it and plate it as a control because bacteria will be present on meat that has been out for five days. I will differentiate the bacteria attributed to rotting meat from the bacteria attributed to the sutures, and make my conclusions. 

When I saw Dr. Patel's patients postoperatively in his office, some complained of itchiness and irritation near the incision. This could be a sign of developing infection, and I wondered if it might be attributed to the sutures used to close the incision. Of course, there are many things that can cause an infection in the wound, but I may be able to trace it back to the type of suture used by observing bacterial growth.