All posts by TheTraumaPro

Does Initial Hematocrit Predict Shock?

Everything you know is WRONG!

The classic textbook teaching is that trauma patients bleed whole blood. And that if you measure the hematocrit (or hemoglobin) on arrival, it will approximate their baseline value because not enough time has passed for equilibration and hemodilution. As I’ve said before, you’ve got to be willing to question dogma!

The trauma group at Ryder in Miami took a good look at this assumption. They drew initial labs on all patients requiring emergency surgery within 4 hours of presentation to the trauma center. They also estimated blood loss in the resuscitation room and OR and compared it to the initial hematocrit. They also compared the hematocrit to the amount of crystalloid and blood transfused in those areas.

Patients with lower initial hematocrits had significantly higher blood loss and fluid and blood replacement during the initial treatment period. Some of this effect may be due to the fact that blood loss was underestimated, or that prehospital IV fluids diluted the patient’s blood counts. However, this study appears sound and should prompt us to question the “facts” we hear every day.

Bottom line: Starling was right! Fluid shifts occur rapidly, and initial hematocrit or hemoglobin may very well reflect the volume status of patients who are bleeding rapidly. If the blood counts you obtain in the resuscitation room come back low, believe it! You must presume your patient is bleeding to death until proven otherwise.

Reference: Initial hematocrit in trauma: A paradigm shift? J Trauma 72(1):54-60, 2012.

Pet Peeve: “High Index of Suspicion”

How often have you heard this phrase in a talk or seen it in a print article:

“Maintain a high index of suspicion”

What does this mean??? It’s been popping up in our work for at least the last 20 years. And to me, it’s meaningless.

An index is a number, usually mathematically derived in some way. Yet whenever I see or hear this phrase, it doesn’t really apply to anything that is quantifiable. What the author is really referring to is “a high level of suspicion”, not an index. 

This term has become a catch-all to caution the reader or listener to think about a (usually) less common diagnostic possibility. As trauma professionals, we are advised to do this about so many things, it really has become sad and meaningless.

Bottom line: Don’t use this phrase in your presentations or your writing. It’s stupid. And feel free to chide any of your colleagues who do.

Reference: High index of suspicion. Ann Thoracic Surg 64:291-292, 1997.

Blunt Aortic Injury And New Cars

Car crashes are a significant cause of trauma death worldwide. Aortic injury is the cause of death in somewhere between 16% and 35% of these crashes (in the US). Over the years, automobile safety through engineering improvements has been rising. A recent poster presented at EAST 2012 looked at the effect of these improvements on mortality from aortic injury.

The authors analyzed the National Automotive Sampling System – Crashworthiness Data System database (NASS-CDS) for car model years dating from 1994 to 2010. They included any front seat occupants age 16 or more. Over 70,000 cases were reviewed.

Interesting findings:

  • Overall mortality from aortic injury was 89%
  • 75% of deaths occurred prior to arrival at a hospital
  • Risk for suffering an aortic injury was statistically associated with age >=60, being male, being the front seat passenger, position further back from the steering wheel, and ejection from the vehicle
  • The injury was more likely to occur when speed was >= 60mph, impact occurred with a fixed object, and in SUV vs pickup truck crashes
  • Newer cars protected occupants from aortic injury in side-impact crashes, but the incidence actually increased in frontal-impact crashes

Bottom line: Aortic injury will remain a problem as long as we find ways to move faster than we can walk. Engineers will continue to make cars safer, but the increase in aortic injury in frontal impact in late model cars is puzzling. This phenomenon needs further analysis so that safety can be improved further. Trauma professionals need to keep this injury in mind in any high energy mechanism and order a screening chest CT appropriately.

Related posts:

Reference: Aortic injuries in new vehicles. Ryb et al, University of Maryland and Johns Hopkins. Poster presented at EAST Annual Meeting, January 2012.

Alert! CDC Identifies Major Binge Drinking Problem

The Centers for Disease Control (CDC) released a report on binge drinking in the US last week that is quite alarming. It provides a host of facts that should alarm any trauma professional. And I’m fairly certain that these statistics apply to just about any other country as well.

The study indicated that 1 in 6 adults in the USA is a binge drinker! My understanding of the term binge is that 5 or more alcoholic beverages are consumed at one sitting. Obviously, this behavior puts one at risk for trauma, including interpersonal violence, car crashes, and injuries due to falls. About 80,000 people per year die due to this, and it costs our economy over $200B per year.

Here are some of the factoids that were uncovered:

  • The highest number of binge drinkers was in the 18-34 year age group 
  • The 65+ year age group drank the most during a binge (!!) 
  • Most alcohol-impaired drivers were binge drinking (!!!) 
  • The average highest number of drinks consumed during a binge was 8. In an average drinker, the resulting blood alcohol concentration would be about 0.24 mg/dl, or 3 times the legal limit. 
  • The northern tier states tended to have the most binge drinkers (18-25%)

What can trauma professionals do? In the US, all Level I and II trauma centers verified by the Amican College of Surgeons are required to screen all patients for problems with alcohol. This requirement should be adopted at all centers, regardless of country or level. Additionally, specific prevention programs should be developed, and existing community programs should be supported.

Reference: CDC Vital Signs -Jan 2012