New Technology II: Helping Paraplegics and Quadriplegics to Walk
The second company that makes a device to assist walking in spinal cord injured patients is Berkeley Bionics. Their exoskeleton is lighter (45 pounds) and more form-fitting, making it easier to maneuver indoors. It can operate for up to 6 hours between charges. The unit does require operator assistance in the form of a pair of canes for balance.
Prices were not available for the products from both Berkeley and Rex. However, the technology looks promising for several reasons. It allows the subject to stand upright, putting weight on their feet. This helps increase muscle tone and maintain joint flexibility. It also decreases pressure problems caused by remaining seated.
These devices are in an early stage right now. As the technology advances, expect to see smaller bionics with better (smoother) computer control, and more access for people with higher spinal cord injuries.
Disclaimer: I have no financial interest in Berkeley Bionics.
New Technology I: Helping Paraplegics and Quadriplegics to Walk
Several companies are working on technology to enable people with spinal cord injuries to walk again. Dave MacCalman, a New Zealand Paralympian with a cervical cord injury, recently purchased a robotic exoskeleton from Rex Bionics. This device allowed him to walk for the first time in 30 years.
This exoskeleton is somewhat bulky (84 pounds), and allows only slow movement. The unit does not use crutches, but does require a modest amount of arm strength to use. It allows walking up slopes and building standard stairs with a handrail. To go down stairs, the user steps down facing backwards. The power supply lasts 3-4 hours.
This technology has only been in development for nonmilitary use for a few years. I expect that great strides (!) will be made as more companies join the fray. Tomorrow I’ll feature an exoskeleton from a US company, and point out the pros and cons of the two devices.
Disclaimer: I have no financial interest in Rex Bionics.
Fatigue is a major problem for many healthcare providers, from prehospital those working in post-discharge institutions. Some interesting and underappreciated statistics about work-related injuries and shift work:
- Work related injuries increase on off-shifts. Compared to day shift, 15% more injuries occur on evenings and 28% more on nights.
- When working long shifts, there is a 13% increase in injuries after 10 hours, and a 30% increase after 12 hours.
- When working consecutive nursing shifts, there is an 8% increase in injury risk the 2nd night, a 38% increase the 3rd night, and a 70% increase the 4th night.
We know sleep deprivation and fatigue are bad. The laundry list of adverse effects is lengthy and includes confusion, memory problems, depression, weight gain, headache, diabetes, cardiovascular disease, and as we’ve discussed all week, serious performance problems.
What can be done about it? The key is to raise awareness, along with acceptance of the remedies. Many hospital workplaces are doing something about it. Here are some successful interventions that reduce workplace fatigue:
- Authorize a real break system. A break is a 30 minute period which is ideally away from the immediate work setting, where there are no disturbances (phone, pager)
- Ensure effective “handoffs” between co-workers when taking breaks
- Encourage workers to identify fatigue in their co-workers and find ways to decrease it
- Modify schedules to adhere to the Institute of Medicine’s standards
* No more than 20 hours of overtime a week
* Limit the number of 12 hours shifts
* No double shifts
Some workplaces are unfortunately not as progressive, and the work culture takes pride in showing how individuals can “power through” even when tired. Just remember, this is bad for you and bad for your patients. As you grow older, it becomes even more difficult and dangerous. It’s only a matter of time before someone, somewhere goes too far, and they or their patient will end up “dead tired.”
We’ve all experienced it. That moment of wandering attention. The semi-blank stare. You can’t remember that question you were going to ask. It’s the “zoning out” phenomenon. It happens more frequently when you are fatigued or sleep-deprived. What is really happening in your head when you go blank? Your’re neither asleep nor fully awake.
The University of Wisconsin at Madison has been able to shine a little light on this problem. While we are awake, neurons in the cerebral cortex fire irregularly, which results in rapid fluctuations on an EEG. As we sleep, the brain alternates periods that look like an awake EEG with periods where the neurons stop firing altogether.
The researchers monitored activity in focal areas of rat brains (tough to extrapolate this one). They found that after prolonged sleep deprivation, small random areas of the brain would switch off and look like they were asleep. However, the animal appeared to be awake, and the EEG looked like that of an awake rat. If neurons switched off in the motor strip while tasks were being performed, performance errors increased dramatically.
The lead investigator believes that these “tired neurons” may be responsible for attention lapses, poor judgment, mistakes and irritability when we haven’t gotten enough sleep, but don’t feel sleepy. This phenomenon may represent a global state of neural instability, and individual neurons switch off to save energy or restore themselves.
Reference: Nature 472:443-447, April 27, 2011.
The effects of fatigue on the surgeon have been looked at a number of times over the years. Most of this work focuses on resident physicians, however. Another problem with the majority of these studies is that they did not test the surgeon or resident on tasks that reflect real life practice.
A study from Arizona State University used a laparoscopic simulation that tested both psychomotor and cognitive skills that would be called on during real surgical procedures. In addition to the purely manual task of stacking varied sizes of rings using laparoscopic instruments, exercises were developed and validated that tested attention, tracking and other critical components. Monitored parameters included hand and tool movement, smoothness and economy of motion, and time required to complete the task. An overall proficiency score was calculated.
Five residents and nine attending physicians were tested. They were all given 4 practice sessions with the simulator before the study began. Sleep hours and caffeine use during call were recorded using a questionnaire. Each individual was then tested three times prior to being on call and three times post-call.
As would be expected, attending surgeons showed higher proficiency scores than residents both pre-call and post-call. However, both groups experienced significant declines in proficiency and significant increases in cognitive errors post-call. Interestingly, attending surgeons made 25% fewer cognitive errors post-call when compared to residents, and their psychomotor skills were unchanged. This suggests that the attendings were focused on skills at the expense of decision making.
Two other interesting items from this paper:
- Errors increased exponentially with subjective reported fatigue in the attending surgeons. This means that a small amount of attending surgeon fatigue led to a large increase in errors. The implication is that the older attendings had less reserve, and that their greater skills and experience could be quickly overwhelmed.
- Caffeine intake had no effect on motor skills or cognitive errors.
Bottom line: Fatigue from post-call sleep deprivation impedes psychomotor and cognitive functions, as well as performance. Residents are affected more than attending surgeons, but attending performance declines more rapidly as they grow fatigued. As any post-call surgeon knows, activities the day after call should be limited to the mundane to optimize patient safety.
Reference: The effect of fatigue on cognitive and psychomotor skills of trauma residents and attending surgeons. Am J Surg 196(6):8133-820, 2008.