CleveMed Blogs

On New Years Eve 2009, Travis Pastrana found himself sitting in a rally car, mentally preparing to jump 269 feet across a body of water to break the world record for longest rally car jump. His instructions were clear: begin on the Pine Street Pier in Long Beach, California, take off on a ramp, fly approximately 50 feet above the water, and successfully land on a floating barge about 300 feet away. In the event of failure, he had a scuba tank, as well as rescue crews on the water.

CleveMed had the opportunity to use the BioRadio and BioCapture software to collect physiological data, as well as the car’s acceleration relative to free-fall, during Pastrana’s practice runs. Electrocardiogram (ECG) electrodes and a respiratory effort belt were attached to Pastrana, and the BioRadio was set up to measure G-forces in the car and characteristics such as heart rate and breathing rate were derived. The BioRadio monitored Pastrana’s entire jump, and physiological data collected provided fascinating information about the physiological response Pastrana experienced related to performing such a dangerous and adrenaline-filled stunt.

So, here’s the physiology of Travis Pastrana’s 269-foot jump:

As Pastrana sat waiting to accelerate forward his heart rate was elevated at approximately 107 beats per minute (bpm). His breathing patterns were relatively normal at this time, but his respiratory rate was also elevated.

As Pastrana began his approach, heart rate increased to 110 bpm. Additionally, right as he began to accelerate he took a very deep breath. After this initial breath Pastrana’s breathing was very shallow and rapid.

Upon reaching the end of the ramp where the rally car began its flight, Pastrana’s heart rate was 122 bpm. In addition, at the moment the car reached the edge of the ramp, Pastrana held his breath, and continued to hold it the entire time in the air. During this mid-air flight, Pastrana’s heart rate was approximately 130 bpm.

When the rally car landed on the opposite ramp, Pastrana exhaled deeply, and was quickly followed by a deep inhale and gradually slower respiration rates. In addition, when his rally car made impact with the ramp, Pastrana’s heart rate was 138 beats per minute. Once the car began decelerating, his heart rate gradually decreased until reaching the average normal resting heart rate. This physiological data is significant because it provides insight into the body’s reaction to extreme stress.

But other explanations for Pastrana’s physiological response could be attributed to the physical forces he experienced during his rally car’s flight. It was seen that as Pastrana began accelerating, his car was under approximately 1G of force, and at take-off it was as high as 5G’s. You can read about it here, from “The Physiology of a 269-foot Jump” as seen in BioRadio Research & Education Quarterly, Summer 2010. You can also see a screen-shot of Pastrana’s physiological data collected by BioRadio here!

In conclusion, BioRadio provided a clear image of the physiological response of an extreme sportsman. Even though Pastrana has been performing dangerous stunts for over a decade, it is evident that he still experiences stress and probably excitement during his jaw dropping stunts!

Last week, I wrote about the new GSR sensor that will expand BioRadio’s applications, and now it’s time to discuss, yet another new accessory that CleveMed is offering for the BioRadio: the skin temperature sensor.

In 1833 Michael Faraday noticed the resistance of silver sulfide decreased dramatically as temperature increased. This was the first documented observation of a compound that could be used as a thermistor. However, thermistors were difficult to produce and therefore commercial production did not begin until the 1930s with the technology vastly improving since then. The second new accessory integrated into the BioRadio is a skin/surface probe that can detect temperatures in the range of 70°F through 110°F. This probe, which is a thermistor, derives measurements based on a resistor whose resistance varies with changing temperature.

Thermistors can be used in a variety of applications relating to skin temperature measurements. First, it could be used to monitor dangerous physiological reactions, such as heat stroke in applications such as athletics and emergency workers. Next, thermistors could be used in a research setting involving the skin temperature of first responders, such as firefighters. If a new or improved material is developed for safety gear, the thermistor could be used to demonstrate the gear’s efficacy at shielding firefighters from heat. Similarly, thermistors could be used in the military to examine potential safety gear for personnel who are fighting in a war. Thermistors could also be used in sports medicine measurements, such as exploring the body’s ability to thermoregulate while performing a variety of strenuous activities for an extended period of time. Additionally, similar strategic experimental sensor placements could be executed in order to determine if and how certain behaviors, experiences, and actions affect body temperature. Such findings could provide a deeper understanding of mental and physiological processes that could ultimately be used for a variety of therapeutic and pharmacological interventions.

This post is an adaptation from “New GSR & Skin Temp Sensors Expand BioRadio Applications” as seen in BioRadio Research & Education Quarterly, Summer 2010.

CleveMed will soon be offering two new accessories for the BioRadio — galvanic skin response (GSR) and skin temperature sensors. These accessories further expand the possibilities of the BioRadio for research and educational applications. Ranging from psychology-related fields, in exploring connections between behavior and emotion, to sports medicine fields, in exploring the correlations between exercise and physiological response, these new accessories can provide valuable information for a broad range of applications. (This week, I will be writing about the new GSR sensor, and we’ll discuss the skin temperature sensor next week.)

In ancient China, a suspect would hold rice in the mouth during a prosecutor’s speech. If at the end the suspect could not successfully spit out all the rice, they were considered guilty. It was believed a lack of salivation was attributed to anxiety and therefore guilt. With today’s technology, there is no need for rice! Biomedical sensors can measure skin conductivity from the fingers and/or palms to provide a modern mechanism to measure emotions. The GSR sensor is highly sensitive to emotions in some people and can be used as a polygraph, or lie detector test. GSR has also been used as an index for those who need some measurable parameter of a person’s internal “state”. Physiologically, GSR quantifies sweat gland activity and changes in the sympathetic nervous system. Measured from the palm or fingertips, there are changes in relative conductance of a small electrical current between the electrodes. The activity of sweat glands in response to sympathetic nervous stimulation (increased sympathetic activation) results in an increase in conductance. There is a relationship between sympathetic activity and emotional arousal, although one cannot identify the specific emotion being elicited. Fear, anger, startle response, orienting response and sexual feelings are all among emotions which may produce similar GSR responses. This new accessory offers research labs and schools a new interface to use to provide insightful information about emotional response in a variety of applications.

This post is an adaptation from “New GSR & Skin Temp Sensors Expand BioRadio Applications” as seen in BioRadio Research & Education Quarterly, Summer 2010.

"You get what you pay for" – an idiom that has been around just about forever. It suggests that the quality of a product improves or increases with the amount of money one pays for that product. But for medical devices, quality products need to equate to more than a just a price tag.

Quality medical devices need to equate to a commitment – a commitment from top executive management that the products a company produces, not only meet “customer” requirements, but are safe and effective for their intended use. This commitment is to be communicated to all individuals at all levels of the organization who need to "buy–in" to it - and since this commitment is driven from the top down, employee resistance or "push back" should be reduced into the "slim to none" category!

Because they know their job functions best, employees need to become actively involved in the development of processes and procedures specific to their area of responsibility. These processes and procedures will evolve into the company’s "bible" or Quality System that guides and directs the operation.

"Customers" can be "internal" (engineering may be a customer of marketing, manufacturing may be a customer of sales) as well as external (regulatory agencies are customers of the Quality & Regulatory department, the end user or patient is a customer of sales or product support). A quality medical device is produced when customer requirements and specifications are translated into attainable and realistic design inputs. These inputs will develop into a finished medical device which, prior to being released to market, must go through extensive verification/validation testing to ensure the medical device functions according to specifications and is indeed safe and effective.

Consistency is paramount. Adhering to those employee developed processes and procedures such as purchasing items used in manufacturing only from pre-determined, experienced and competent suppliers are instrumental in maintaining the quality of a medical device.

Lastly, the commitment to quality cannot ever become stagnant. Customer requirements, customer feedback, processes and procedures used in product design and manufacturing as well as the infrastructure of the business itself must be continuously monitored, assessed, measured and improved upon if the medical device organization is to remain competitive, profitable and compliant with regulatory agencies.

Notice that throughout this blog cost was never mentioned? Sometimes you get a lot more than what you pay for!