Differences in the mechanical properties of intestinal tissue based on preservation freezing duration and temperature.

In this study, tissue samples were stress tested to determine if freezing duration and temperature alter their mechanical properties. Tissue samples taken from the small intestine of pigs were assigned to 5 groups: fresh tissue, -28.9 °C for 7 days, -62.

Testing oxygenated microbubbles via intraperitoneal and intrathoracic routes on a large pig model of LPS-induced acute respiratory distress syndrome.

With a mortality rate of 46% before the onset of COVID-19, acute respiratory distress syndrome (ARDS) affected 200,000 people in the US, causing 75,000 deaths. Mortality rates in COVID-19 ARDS patients are currently at 39%. Extrapulmonary support for ARDS aims to supplement mechanical ventilation by providing life-sustaining oxygen to the patient.

Development of a multi-patient ventilator circuit with validation in an ARDS porcine model.

Purpose: The COVID-19 pandemic threatens our current ICU capabilities nationwide. As the number of COVID-19 positive patients across the nation continues to increase, the need for options to address ventilator shortages is inevitable. Multi-patient ventilation (MPV), in which more than one patient can use a single ventilator base unit, has been proposed as a potential solution to this problem.

Preperitoneal insufflation pressure of the abdominal wall in a porcine model.

Background: Most complications and adverse events during laparoscopic surgery occur during initial entry into the peritoneal cavity. Among them, preperitoneal insufflation occurs when the insufflation needle is incorrectly placed, and the abdominal wall is insufflated. The objective of this study was to find a range for static pressure which is low enough to allow placement of a Veress needle into the peritoneal space without causing preperitoneal insufflation, yet high enough to separate abdominal viscera from the parietal peritoneum.

Computational optimization of a novel atraumatic catheter for local drug delivery in coronary atherosclerotic plaques.

Early identification and treatment of high-risk plaques before they rupture, and precipitate adverse events constitute a major challenge in cardiology today. Computational simulations are a time- and cost-effective way to study the performance, and to optimize a system. The main objective of this work is to optimize the flow of a novel atraumatic local drug delivery catheter for the treatment of coronary atherosclerosis.

Preliminary Evaluation of the Viability of Peritoneal Drainage Catheters Implanted in Rats for Extended Durations.

: In developing a novel peritoneal oxygenation therapy, catheters implanted into the peritoneal cavity became obstructed with omental tissue and prevented the infusion and removal of fluid from the peritoneal cavity. The obstruction of peritoneal catheters is a significant failure in researching various peritoneal treatments as further fluid administration is no longer possible. The purpose of this preliminary study was to determine the most effective catheter design for infusion and removal of fluid into the peritoneal cavity of rats.

Design and Validation of a Biosensor Implantation Capsule Robot.

We have proposed a long-term, noninvasive, nonrestrictive method of delivering and implanting a biosensor within the body via a swallowable implantation capsule robot (ICR). The design and preliminary validation of the ICR's primary subsystem-the sensor deployment system-is discussed and evidence is provided for major design choices. The purpose of the sensor deployment system is to adhere a small biosensor to the mucosa of the intestine long-term, and the modality was inspired by tapeworms and other organisms that employ a strategy of mechanical adhesion to soft tissue via the combined use of hooks or needles and suckers.

Design of a Wireless Medical Capsule for Measuring the Contact Pressure Between a Capsule and the Small Intestine.

A wireless medical capsule for measuring the contact pressure between a mobile capsule and the small intestine lumen was developed. Two pressure sensors were used to measure and differentiate the contact pressure and the small intestine intraluminal pressure. After in vitro tests of the capsule, it was surgically placed and tested in the proximal small intestine of a pig model.

Design and preliminary evaluation of a self-steering, pneumatically driven colonoscopy robot.

Colonoscopy is a diagnostic procedure to detect pre-cancerous polyps and tumours in the colon, and is performed by inserting a long tube equipped with a camera and biopsy tools. Despite the medical benefits, patients undergoing this procedure often complain about the associated pain and discomfort. This discomfort is mostly due to the rough handling of the tube and the creation of loops during the insertion.

Intestinal Manometry Force Sensor for Robotic Capsule Endoscopy: An Acute, Multipatient In vivo Animal and Human Study.

Goal: Development of a new medical device class generally termed robotic capsule endoscopes (RCE) is currently being pursued by multiple research groups. These maneuverable devices will allow minimally invasive diagnosis and treatment of intestinal pathologies. While the intraluminal pressures related to the migrating motor complex (MMC) are well understood, no previous study has measured the active contact forces exerted by the human small bowel wall on a solid, or near solid bolus such as an RCE.

Design and Preliminary Experimental Investigation of a Capsule for Measuring the Small Intestine Contraction Pressure.

A tethered pressure measurement capsule was developed for measuring the small intestine contraction pressure to assist in locating capsules within the gastrointestinal (GI) tract and quantifying the contact force between the capsule and the small intestine lumen. The capsule was calibrated statically and dynamically in depth-controlled water at body temperature (37-38 °C). In vitro tests were performed on an intestinal simulator to verify the measurement function of the capsule.

A bio-inspired attachment mechanism for long-term adhesion to the small intestine.

To achieve long-term attachment of capsule endoscopes (CEs) and miniature biosensors in the human gastrointestinal (GI) tract, a tissue attachment mechanism (TAM) was designed, optimized and tested for safety and adhesive capabilities on excised tissue in vitro and in vivo on a live pig model. Six TAMs were tested for their attachment strength in an in vitro attachment tensile experiment in which each TAM was tested on three different proximal intestine tissue samples. The maximum strength and average value are 8.

Evaluation of peritoneal microbubble oxygenation therapy in a rabbit model of hypoxemia.

Alternative extrapulmonary oxygenation technologies are needed to treat patients suffering from severe hypoxemia refractory to mechanical ventilation. We previously demonstrated that peritoneal microbubble oxygenation (PMO), in which phospholipid-coated oxygen microbubbles (OMBs) are delivered into the peritoneal cavity, can successfully oxygenate rats suffering from a right pneumothorax. This study addressed the need to scale up the procedure to a larger animal with a splanchnic cardiac output similar to humans.

Intestinal biomechanics simulator for robotic capsule endoscope validation.

This work describes the development and validation of a novel device which simulates important forces experienced by Robotic Capsule Endoscopes (RCE) in vivo in the small intestine. The purpose of the device is to expedite and lower the cost of RCE development. Currently, there is no accurate in vitro test method nor apparatus to validate new RCE designs; therefore, RCEs are tested in vivo at a cost of ∼$1400 per swine test.

Systemic oxygen delivery by peritoneal perfusion of oxygen microbubbles.

Severe hypoxemia refractory to pulmonary mechanical ventilation remains life-threatening in critically ill patients. Peritoneal ventilation has long been desired for extrapulmonary oxygenation owing to easy access of the peritoneal cavity for catheterization and the relative safety compared to an extracorporeal circuit. Unfortunately, prior attempts involving direct oxygen ventilation or aqueous perfusates of fluorocarbons or hemoglobin carriers have failed, leading many researchers to abandon the method.

Measurements of the contact force from myenteric contractions on a solid bolus.

The development of robotic capsule endoscopes (RCEs) is one avenue presently investigated by multiple research groups to minimize invasiveness and enhance outcomes of enteroscopic procedures. Understanding the biomechanical response of the small bowel to RCEs is needed for design optimization of these devices. In previous work, the authors developed, characterized, and tested the migrating motor complex force sensor (MFS), a novel sensor for quantifying the contact forces per unit of axial length exerted by the myenteron on a solid bolus.

Small intestine mucosal adhesivity to in vivo capsule robot materials.

Multiple research groups are investigating the feasibility of miniature, swallowable, in vivo, untethered robots that are capable of traversing the small intestine for the purpose of acquiring biometrics and performing simple surgical procedures. A mathematical model of the intraluminal environment will speed the development of these so-called Robotic Capsule Endoscopes (RCEs), and to this end, the authors, in previous work, initiated a comprehensive program for characterizing both the active and passive forces exerted by the small intestine on an RCE-sized solid bolus. In this work, forces due to adhesivity between RCE materials and the mucosa are investigated.

Characterization and experimental results of a novel sensor for measuring the contact force from myenteric contractions.

The intraluminal pressures and traction forces associated with the migrating motor complex are well understood; however, the contact forces directly exerted by the bowel wall on a solid, or near solid, bolus have not previously been measured. Quantifying contact forces is an important component to understanding the net force experienced by an in vivo robotic capsule endoscope. In this paper, we develop a novel sensor, the migrating motor complex force sensor (MFS), for measuring the contact force generated by the contracting myenteron of the small intestine.

Single-port-access surgery with a novel magnet camera system.

In this paper, we designed, built, and tested a novel single-port access laparoscopic surgery (SPA) specific camera system. This device (magnet camera) integrates a light source and video camera into a small, inexpensive, portable package that does not compete for space with the surgical tools during SPA. The device is inserted through a 26-mm incision in the umbilicus, followed by the SPA port, which is used to maintain an insufflation seal and support the insertion of additional tools.

Preliminary mechanical characterization of the small bowel for in vivo robotic mobility.

In this work we present test methods, devices, and preliminary results for the mechanical characterization of the small bowel for intra luminal robotic mobility. Both active and passive forces that affect mobility are investigated. Four investigative devices and testing methods to characterize the active and passive forces are presented in this work: (1) a novel manometer and a force sensor array that measure force per cm of axial length generated by the migrating motor complex, (2) a biaxial test apparatus and method for characterizing the biomechanical properties of the duodenum, jejunum, and ileum, (3) a novel in vitro device and protocol designed to measure the energy required to overcome the self-adhesivity of the mucosa, and (4) a novel tribometer that measures the in vivo coefficient of friction between the mucus membrane and the robot surface.

Single port access surgery with a novel Port Camera system.

In this work, the authors designed, built, and tested a novel port camera system for single port access (SPA) laparoscopic surgery. This SPA Port Camera device integrates the monitor, laparoscopic camera, and light source into an inexpensive, portable cannula port. The device uses a 2-channel SPA port inserted through an umbilical incision, similar to traditional SPA.

An integrated port camera and display system for laparoscopy.

In this paper, we built and tested the port camera, a novel, inexpensive, portable, and battery-powered laparoscopic tool that integrates the components of a vision system with a cannula port. This new device 1) minimizes the invasiveness of laparoscopic surgery by combining a camera port and tool port; 2) reduces the cost of laparoscopic vision systems by integrating an inexpensive CMOS sensor and LED light source; and 3) enhances laparoscopic surgical procedures by mechanically coupling the camera, tool port, and liquid crystal display (LCD) screen to provide an on-patient visual display. The port camera video system was compared to two laparoscopic video systems: a standard resolution unit from Karl Storz (model 22220130) and a high definition unit from Stryker (model 1188HD).