Nivedha Senthil

During the first week of the Clinical Immersion Program, my teammates and I had the opportunity to shadow different physicians in the surgical department at UI Health. During this time, we observed various devices, workflows, and equipment used by medical professionals and tried to identify positive aspects of the device and aspects that could be improved.

Good Design: Video Laryngoscope

Activity:

This video laryngoscope was used to intubate patients under general anesthesia. In this setting, it was operated by the anesthesiologist or Nurse Anesthetist (CRNAs) who intubated the patient. To intubate the patient using this device, the anesthesiologist first tested the light and camera mounted at the tip of the laryngoscope blade. After this, they inserted the blade into the patient’s mouth and visualized the vocal cords. The screen to the left of the patient displayed the video captured by the camera on the laryngoscope, allowing the anesthesiologist to clearly see the vocal cords and guide the intubation tube into the trachea.

Environment:

Generally speaking, the video laryngoscope can be used in any clinical environment where the larynx and vocal cords need to be visualized. However, since we were primarily shadowing surgeons, we saw it being used while prepping the patient in the operating room.

Interaction:

The most relevant interaction between the laryngoscope and the user occurs when the user inserts the blade into the patient’s mouth to visualize the vocal cords. The camera allows for real-time visualization of the vocal cords on a screen next to the patient. This helps the user navigate the pharynx and larynx of a patient as they insert the intubation tube.

Object:

Objects in this environment that directly interact with the laryngoscope include the cable and wire that connect the laryngoscope camera to a screen and socket, as well as the intubation tube. Indirectly, anything that affects the orientation and position of the patient can also affect how the laryngoscope interacts with the environment. Some examples of this include the bed the patient is lying on and cushions that lift the patient’s head.

Users:

The primary users of this equipment are people certified and trained to intubate patients. In a clinical environment, this includes (but is not limited to) anesthesiologists, other physician specialties, CRNAs, respiratory therapists, and Advanced Practice Registered Nurses. In this case, the patients are on the receiving end of this equipment, and thus, it is important to keep patient safety and comfort in mind when designing this tool.

Bad Design: Portable Pulse-Oximeter

Activity:

The portable pulse oximeter was used to monitor the vitals of a patient while transferring them from the outpatient operating room to the recovery room. The pulse oximeter was securely attached to the patient’s finger using tape and was connected to an output screen via a long cable (we didn’t get to measure the length of the cable).

Environment:

The device was placed inside the stretcher next to the patient. In this scenario, the environment of the device is limited to the stretcher, but it could be used in other clinical settings.

Interaction:

When young pediatric patients come out of general anesthesia, they are restless, constantly moving and turning in their stretcher. This caused the wire connecting the pulse oximeter to the output screen to wrap around the patient and blankets, posing a danger to the patient. To prevent this, the nurse repeatedly removed the cable from the patient and tried to secure it to the side of the stretcher.

Object:

Objects in this environment that directly interacted with the pulse oximeter device were blankets. As mentioned before, the cable wrapped around the blankets and patient as the patient turned around.

Users:

The primary user of this equipment is the patient. Medical professionals indirectly use it by observing and monitoring vital signs.

Extra: 

Overall, the device was easy to carry and move while the patient was being transported. However, there were some limitations when using the device on pediatric patients.

This week, we shadowed a myriad of general surgery cases ranging from neonatal patients to geriatric patients. From an engineering perspective, the resection of non-palpable breast lesions particularly stood out to me. These types of lesions cannot be identified or felt during physical breast examinations; because of this, they can only be identified via a mammogram, ultrasound, or MRI. During surgery, surgeons used a variety of detection and imaging tools to identify and completely remove the lesion because they cannot feel a distinction between normal breast tissue and the lesion. I discuss the steps in more detail in my storyboard.

Step 1: Mammogram

The patient either comes into the clinic for a mammogram. Some pain points in this step are explained below. Non-palpable breast lesions can only be identified using a mammogram, MRI, or ultrasound. Thus, detection of these lesions relies on a patient noticing and recognizing other symptoms of breast lesions such as pain or discharge and having access to imaging systems such as the ones listed above.

Step 2: Imaging reveals non-palpable breast lesions.

Imaging (MRI, mammogram, or ultrasound) should reveal irregularities in the breast tissues. According to the literature, this can come in many different forms such as masses, calcifications, masses with calcifications, or architectural distortion.

Step 3: RFID Tag is inserted into the lesion

The morning of the operation, the surgeon, using ultrasound, inserts an RFID Tag into the lesions. The RFID Tag is a passive device that can receive energy from radio waves generated by the detection probe. This allows the detection probe to locate the tag and, by extension, the location of the non-palpable lesion during surgery. Some pain points in this step are explained below. The patient has to undergo another procedure hours prior to surgery in which a two-inch incision is made. Although it is less invasive, it still puts them at a greater risk. Moreover, the chip is increasingly difficult to place in dense breast tissue, making it more difficult to apply and track during the procedure.

Step 4: Surgeon determines the location and positioning of RFID Tag while the patient is being prepped in the operating room.

While the patient is being prepped and positioned in the operating room, the surgeon uses a probe that measures the distance between the RFID Tag and the surface of the skin. Using this device, the surgeon estimates the location of the lesion.

Step 5: Surgeon removes the lesion.

After the patient is prepped and ready for surgery, the surgeon excises the lesion from the body, using the RFID Tag and detection probes as guides in locating and excising the tumor. Pain points in this include general complications of surgery such as bleeding from incision or nerve pain. Moreover, the RFID Tag is surrounded by glass to prevent interactions between the tag and electric bovie. However, this also poses a risk to the patient as too much pressure on the tag can break the glass and pierce the skin.

Step 6: Use X-Ray to confirm the RFID Tag is removed from the patient.

An X-ray of the removed mass is taken to confirm that the surgeon appropriately removed the RFID Tag. This is to ensure that both the lesion and RFID Tag are fully removed from the patient. To do this, the surgeon used the Faxitron OR Specimen System – a portable cabinet x-ray system inside the operating room.

Step 7: Close the incision.

After the removal of the lesion, the surgeons closed the incision using a combination of sutures in the dermal and epidermal layers of the skin and Dermabond. If the skin is not sutured properly, the patient is at risk of infection, scarring, and improper healing.

Step 8: The patient is moved into the recovery rooms.

After the procedure, the patient is moved into the recovery room where they are monitored overnight for complications.

Summary of Peer-Reviewed Review Paper:

I found a review paper that compares outcomes of wire-guided localization and RFID Tags in removing non-palpable breast lesions. In this paper, they included 7 studies consisting of a total of 1151 patients and 1344 tags. They found that the re-excision rate was comparable at 13.9% and that only one complication was found for both methods. Overall, they concluded that RFID Tags were a safe and effective alternative to the traditional wire-guided localization method used.

Citation: Tayeh, S., Wazir, U., & Mokbel, K. (2021). The Evolving Role of Radiofrequency Guided Localisation in Breast Surgery: A Systematic Review. Cancers, 13(19), 4996. https://doi.org/10.3390/cancers13194996

After three weeks of observing pediatric surgery and the NICU, I noticed that many of the tools and equipment used in pediatrics are adult equipment adapted for pediatrics. For instance, even the smallest intubation tubes were too heavy for the baby, with the weight of it dragging the baby’s head. To overcome this, they propped the side of the baby’s head with towels and tried to elevate the tubing to alleviate some of the drag. Another example I saw was in the operating room when the anesthesiologist was securing the pulse-oximeter on the baby. The flexible pulse-oximeter was too large to be easily positioned or wrapped around the baby’s fingers and toes. Because of this, it took the anesthesiologist quite a while to get it properly secured and working, increasing the time the patient is under anesthesia. I developed my need statement from this observation.

First Iteration:

Physicians cannot accurately measure oxygen-saturation in newborn and NICU patients due to poor securing of the pulse-oximeter on the patient, so physicians need a better way to more accurately measure oxygen-saturation.

Population: Physicians

Opportunity: Securing Pulse-Oximeters on NICU and Newborn Patients.

Outcome: More accurately measure oxygen-saturation

Second Iteration:

Anesthesiologists cannot accurately measure oxygen-saturation in newborn and NICU patients due to poor securing of the pulse-oximeter on the patient’s fingers and toes, so physicians need a better way to more accurately measure oxygen-saturation.

Population: Anesthesiologists

Opportunity: Securing Pulse-Oximeters on NICU and newborn Patients.

Outcome: More accurately measure oxygen-saturation

Third Iteration:

Anesthesiologists cannot accurately measure oxygen-saturation in babies under a certain size  and take a greater amount of time to secure the pulse-oximeter around the baby’s fingers or toes because the pulse-oximeter cannot efficiently be positioned and secured on the fingers and toes of these patients, thus they need a better way to secure the pulse-oximeter which reduces the time spent on securing the device and increases the accuracy of the oxygen-saturation readings.

Population: Anesthesiologists

Opportunity: Securing pulse-oximeters on babies under a certain size (I don’t know the exact size range at the moment) and reduce time it takes to secure the pulse-oximeter

Outcome: More accurately measure oxygen-saturation and reduce time spent securing the device.

For my patent search this week, I decided to research methods to secure gastrostomy tubes, or g-tubes for short. The need statement is written below.

Pediatric surgeons require a method to secure g-tubes to the patient’s abdomen to prevent accidental removal of the device, thus increasing patient safety and decreasing the number of g-tube replacements needed.

The current method of securing gastroenterology tubes includes a small balloon-like device that is attached to the end of the tube (the place of insertion) and inflated upon insertion of the tube into the stomach, along with a tape and lock mechanism that secures the tube and opening to the abdomen. These devices secure and limit the movement of the g-tube, making it less likely to be accidentally removed. However, in young children, this method is not enough; as the product naturally wears over time, children can remove this device from their stomach with force, which is dangerous for the child and forces surgeons to replace the device.

I found a patent (6019746) that modified the device to more easily install and adjust it. The device consists of three parts: a bolster portion with an inflation valve, an apple-shaped balloon member, and a tubular member. From my understanding, the device is inserted into the patient’s stomach and inflated using the inflation valve on the outside of the abdomen. To use the device for feeding, a tube is secured to the cap member through a twist and lock fashion, thereby securing the tube to the gastrostomy device. The short design and the shape of the balloon increase the durability and comfort of the device. They have 11 claims regarding the design and integration of parts.

Currently, this is a commercially available product. However, as we saw in the clinic, the balloon device needs to be continually checked and inflated; deflation of the balloon leads to children easily tampering with and removing the device from their stomach.

Patients require a method to prevent accidental dislodgment of gastrostomy tubes to reduce complications and replacements, as well as to ensure adequate nutritional intake.

To calculate the Total Addressable Market (TAM) of gastrostomy tubes, we multiply the number of gastrostomy tubes placed per year by the cost of the product. Research shows that approximately 200,000 gastrostomy tubes are placed every year, with balloon gastrostomy tubes (the most common type) needing replacement every 6 months. This results in approximately 400,000 gastrostomy tubes being placed each year. 

According to Cook County Health Standard Charges, the average cost of g-tube placement is $532.00. Thus, the TAM is equal to 400,000 units/year * $532 per unit = $212,800,000.