All posts by TheTraumaPro

Fatigue Week: Sleep Deprivation Changes The Way We Make Risky Decisions

I’m kicking of Fatigue Week today, where I’ll be dealing with the issues surrounding lack of sleep. As you all know, trauma professionals are expected to perform even if they have not had adequate sleep. This can occur with certain shift schedules, long periods of work, or due to call schedules and duration of call. What do we really know about the effects of sleep deprivation on us?

Today, we’ll talk about decision making. Neuroscientists at Duke looked at how we approach risky decisions when we are sleep deprived. A total of 29 adults (average age 22) were studied. They were not allowed to use tobacco, alcohol and most medications prior to sleep deprivation, which lasted for 24 hours. They were given a risky decision making task (a controlled form of gambling), and two other tests while in a functional MRI unit to watch areas of brain activation.

The researchers found that, when well rested, the subjects had a bias toward avoiding loss in the gambling test. After a single night of sleep deprivation, this shifted to pursuing gain. The MRI also showed an increased activity in the reward anticipation parts of the brain. Overall decreased vigilance was noted, but this did not correlate with the shift away from risk avoidance.

Bottom line: Sleep deprivation appears to create an optimism bias. Fatigued individuals act like positive outcomes are more likely and negative consequences are less likely. One of the most common and important things that trauma professionals do is to make decisions that may affect patient outcome (e.g. choose a destination hospital, intubate, order and interpret a test, move to the operating room, choose a specific operative procedure). We all have a set of thresholds that help us come to the “right” decision based on many variables. It appears that a single night of sleep deprivation has the potential to skew those thresholds, potentially in directions that may not benefit the patient.

Reference: Sleep deprivation biases the neural mechanisms underlying economic preferences. J Neuroscience 31(10):3712-3718, March 9, 2011.

How Significant is Pneumomediastinum in Children?

Pneumomediastinum seen on chest x-ray after blunt trauma always attracts attention. Possible sources may be related to very serious injuries to the aerodigestive tract. When seen in children, it causes considerable anxiety, which usually results in a very detailed workup and lots of imaging.

Children’s Hospital of Boston looked at the National Trauma Data Bank, as well as 19 years worth of their own records to see whether all the attention is justified. They found 193 patients in the NTDB that met their criteria, and most were in their late teens and had other significant injuries. Of the 17 with isolated pneumomediastinum, none had any other significant injury.

When reviewing their own patient records, they found 18 with pneumomediastinum, and all but one was seen on plain chest x-ray. Most were transferred to the hospital from referring centers, and had been involved in sports-related mechanisms. Half had undergone studies in addition to a chest x-ray before transfer. All were discharged home without any surgical interventions.

Bottom line: Pneumomediastinum is rare in children, even older ones. If associated with significant aerodigestive injuries, it was never an isolated occurrence. Other signs or symptoms were present. Pediatric patients presenting with an isolated pneumomediastinum can be safely observed, using chest x-ray and physical examination alone. More sophisticated studies (CT, barium studies) are not indicated.

Reference: Clinical outcomes and diagnostic imaging of pediatric patients with pneumomediastinum secondary to blunt trauma  to the chest. J Trauma, epub, 2011.

Image Sources for the Trauma Professional’s Blog

I’ve had some questions about where I come up with some of the images I post in this blog. I have a number of sources, including the good old internet as well as my own personal collection. If I do use my own images, I strictly follow these guidelines:

  • They are not related to patients I have taken care of at Regions Hospital.
  • They are at least 10 to 15 years old. If more recent, I will have obtained a consent for it.
  • They are anonymous. There is no identifying information whatsoever.

In order to avoid any confusion in the future, I will provide source info for any images I post.

Thanks, and keep reading!

Trauma 20 Years Ago: Continuous Epidural Analgesia for Rib Fractures

Rib fractures are painful, and lots of rib fractures not only hurt, but can lead to complications or death. We take for granted all the modalities we now have for pain relief with rib fractures:

  • IV narcotics
  • epidural analgesia
  • rib blocks
  • intrapleural analgesia
  • lidocaine patches
  • fracture fixation techniques
  • and more!

In April 1991, we were still trying to figure out if epidural analgesia was any better than IV narcotics. A small prospective study of 32 patients who were awake and alert and had at least 3 rib fractures were given either IV or epidural fentanyl. The drug was administered as an initial bolus, followed by a continuous infusion. A visual analog pain scale was used for titration.

Vital capacity increased significantly in both groups. Epidural analgesia also led to an improvement in maximum inspiratory pressure (which we now know as NIF). IV analgesia led to somewhat troubling increases in pCO2 and decreases in pO2, whereas epidural administration did not. Pain relief was better with the epidural, while side effects were similar.

The authors concluded that epidural analgesia offers several advantages over IV, and stated that it should be the preferred method for patients at high risk for complications following multiple rib fractures. This paper started us on the path to using the epidural for pain management with significant rib fractures.

Reference: Prospective evaluation of epidural and intravenous administration of fentanyl for pain control and restoration of ventilatory function following multiple rib fractures. J Trauma 31(4):443-451, 1991.

IOM Report: Nutrition and Traumatic Brain Injury (TBI)

The Institute of Medicine (IOM) released a report last week summarizing a project that examined the impact of nutrition on head injury. The Department of Defense requested this review because of the significant morbidity and mortality incurred by our armed forces caused by TBI.

The IOM convened a panel of experts that reviewed the available data. As with most such panels, there is a recommendation to engage in additional research. They went a step further, though, and recommended several specific avenues of research, including:

  • Determine optimum levels of blood glucose
  • Study the benefits of insulin therapy
  • Determine the optimal goals for nutrition
  • Look at the effects of supplements and various diets, CDP-choline, creatine, n-3 fatty acids, fish oil and zinc supplements

The most pressing recommendation they made was a call to standardize the feeding regimen for severe TBI patients very early after injury. Specifically, they recommend that nutritional support be started within 24 hours of injury, consisting of 50-100% of the total energy expenditure with 1 to 1.5 g protein per kg body weight. This should be continued for the first 2 weeks after injury. It appears that this intervention limits the intensity of the inflammatory response after TBI and improves outcomes. 

Reference: Nutrition and Traumatic Brain Injury: Improving Acute and Subacute Health Outcomes in Military Personnel. Click to access the document on the IOM site.