Closed-Loop Control for Anesthesia Delivery

Earlier today I commented on my optimism concerning closed-loop control for glucose management.  A different application but somewhat analagous system (i.e., closed-loop) has been developed and tested for anesthesia delivery:

We have developed a proportional-integral-derivative controller allowing the closed-loop coadministration of propofol and remifentanil, guided by a Bispectral Index (BIS) monitor, during induction and maintenance of general anesthesia. The controller was compared with manual target-controlled infusion.

The controller allows the automated delivery of propofol and remifentanil and maintains BIS values in predetermined boundaries during general anesthesia better than manual administration.

You can see the system in action below (video uploaded by Medgadget):

Artificial Pancreas and Closed Loop Control – is it really that far off?

For many years academic researchers and device companies alike have investigated, developed and studied that artificial pancreas.   The system isn’t really a pancreas per se but rather a multi-component system that  continuously measures glucose (via a subcutaneous sensor), uses a computerized closed loop controller to determine the proper insulin infusion rate and and then automatically adjusts insulin delivery via a subcutaneous insulin pump.

Many of these automatic feedback control systems are in clinical trials and there has been enthusiasm generated by NIH and JDRF sponsored research in this field.

I don’t think the artificial pancreas is far off at all, although the first generation may not be the fully automated high performing system that we dream about.  Insulin pumps are reliable and sophisticated control systems have been developed that optimize insulin delivery decisions using a personalized predictive model (i.e., determines future glucose response via an adaptive nonlinear PK/PD equation).   The weak link, in my opinion, is the glucose sensing system.  Continuous glucose monitors have improved but may not be at the point were tight glycemic control is possible.  However, some level of autonomous action does seem feasible – today.


The Cure – devices, transplants, stem cells and stopping beta cell attackers

I’m a proud techno-geek.  As a result, when I think about diabetes I tend to gravitate to technology oriented device solutions.  An Artificial Pancreas, a non-invasive blood glucose meter and interchangeable/inter-operable pumps and meters.

And, I like data, lots of data.

While technology is very important, the holy grail of diabetes research is not the future medical device with Star Trek capability unless it is able to promote and bring about a cure.

Pancreas and islet transplants have benefit individuals but have not yet provided a treatment that is worth the risk for most individuals.  And, even if the risks were mitigated, the lack of suitable donors is another impediment.

To me, the ideal is the development of implantable islets from adult stem cells take from the same individual who will receive them.  Rejection of the islets would be minimized and the us of immunosuppressive drugs, I would guess, could be minimize.  In short, Autologous Stem Cell Therapy Transplant requiring no immunosuppression

[Read more...]

Here’s your chance – DiabetesMine Design Challenge

DiabetesMine, a leading informational and community web site for people with diabetes, recently announced the kickoff of the 2011 DiabetesMine Design Challenge, a competition that fosters innovation in the creation of new tools designed to improve life with diabetes.

This annual web-based competition, hosted at here, calls for fresh ideas for new devices, web applications, or other instruments designed to help people live better with diabetes. The contest is underwritten by the California HealthCare Foundation (CHCF), an independent philanthropy committed to improving the way healthcare is delivered and financed in California and beyond. It is also supported by the global design and innovation firm IDEO, headquartered in Palo Alto, CA, and endorsed by, the Internet journal of emerging medical technologies.


Read the announcement at DiabetesMine!

Gastric Bypass Surgery Reverses Heart Ailments!

gastric-bypass-surgery.jpgThis is fairly significant news…. gastric bypass does help lose weight and treat diabetes (more here):

Well- who is a candidate for these procedures? Usually patients with a BMI of over 40 or over 35 with health consequences that are obesity related. Does gastric bypass have any effect on diabetes? In a series of 1000 patients, 150 of whom had diabetes, 83% experienced resolution of their diabetes (defined by a normalization of A1c and coming of medications for diabetes) after the surgery

However, there now appears to be additional benefits:

A new report from the Journal of the American College of Cardiology reports that patients who had received gastric bypass surgery not only lost weight but had maintained healthier cardiac health, while also reducing previous cardiac complications spurred by obesity.

Often times when a patient is obese, an increase in the largest portion of the heart, the left ventricle can become larger in mass causing the heart to work harder to pump blood into the body. According to the study, echocardiograms, or ultrasounds of the heart showed a remodeling of the heart structure which included a reduction of left ventricular mass and right ventricular cavity area in patients that had received Gastric Bypass Surgery, a procedure Texas Bariatric Specialists performs.

“Patients now have another reason to add to their check-off list of the benefits of a gastric bypass. Why would anyone severely obese wait any longer when the health risks are too high,” says Texas Bariatric Specialists founder Dr. Nilesh A Patel.
A gastric bypass is a bariatric procedure that is the single largest contributor to these findings and is offered at Texas Bariatric Specialists. In the Laparoscopic gastric bypass surgery procedure, the surgeon makes a small stomach pouch at the top of the stomach, the pouch is later connected to the small intestine bypassing the larger stomach. The gastric bypass can result in complete resolution in type 2 diabetes, hypertension, high blood pressure, sleep apnea, and the loss of 65 percent of excess body fat.

Source: press release

Your new permanent gadget?

The Greener Gadgets Conference suggested a gadget concept that is ‘tattooed’ under your skin and runs on blood by turning glucose and oxygen into electricity. I’m not sure I like the permanence of this system unless, perhaps, it is a glucose meter.
Details here

A Non-invasive Glucose Sensor?

non-invasive-glucose.jpgAnother report of the long sought after non-invasive glucose meter… this one is the size of a cell phone and will be available in a year:

Hong Kong scientists have invented a device to help diabetics measure their blood sugar painlessly for the first time – without pricking their fingers.
The size of a mobile phone, the instrument emits a weaker form of infrared, or near-infrared, which penetrates the skin on the finger and homes in on the bloodstream.
Out of the many components in the blood, the beam is able to identify bits of glucose through the frequency, or wavelengths, they transmit and the amount of blood sugar present would be displayed on the instrument in 10 seconds. 

Considering the near-infrared train wrecks that have preceeded this announcement, the device (if real) is quite an accomplishment. Unfortuantely, there is precious little information available regarding the system although their patent suggests the device does the following:

To predict the blood glucose level of the person using the NIR spectral scan an evaluation model was found based on a population of test subjects. The evaluation model relates NIR absorbance of blood vessels at a first and a second group of wavelengths to a glucose level of the blood vessels . The graph in figure 2 shows the relationship between the NIR absorbance of blood of a body part of the test subjects and the mean value of laboratory tested glucose levels of the test subjects at three sample wavelengths of 940nm, 1310nm and 1550nm. The reference glucose levels are obtained using proven standard laboratory tests on blood samples from the test population. The linear relationship is found using a least squares method. The standard deviation on the mean value of the tested glucose levels for the test population was 10% to 20%. 

Quite remarkably, the measurement system claims to use only six wavelenghts to measure glucose, a trace constituent, amid a background of interferring analytes.
I’m sorry, but I’m not going to hold my breath on this one but will certainly wish the scientific team “good luck, your technology will provide a substantial benefit to glucose testers.”

Medical Device Reduces Blood Pressure

Researchers at the University of Rochester Medical Center are the first in the nation to test an investigational medical device that lowers blood pressure by activating the body