After a car crash, women are more likely to go into shock than men, even when their injuries are less severe, new research shows.

“Women are arriving to the trauma bay with signs of shock more often than men, regardless of injury severity,” said study leader Susan Cronn, a researcher at the Medical College of Wisconsin in Milwaukee. “We need to look further into how and why this is happening.”

For the study, her team looked at clinical injury data from more than 56,000 car crash victims — half men, half women. 

Even though men had more injuries overall, women suffered more injuries to the pelvis and liver, they found. More importantly, women surpassed a shock index greater than 1.0 more often than men. This was true even for those with fewer, less severe injuries. 

Healthy adults have a normal shock index between 0.5 and 0.7. 

Higher numbers may be a warning sign of a life-threatening condition called hemorrhagic shock, in which blood pressure, heart rate and body temperature plummet. Often caused by heavy blood loss, it can be a predictor of premature death.

“Our findings might mean that women’s bodies have less capacity to function when physiological changes occur, that some injuries might have more impact on female bodies, or that female bodies handle blood loss differently than male bodies,” Cronn said. “It might also be that we have been assuming that normal vital signs are the same for everyone regardless of sex, and that we need to re-visit our definition of normal.”

If their results prove to be clinically relevant, researchers said a sex-differentiated shock index may change how first-aid responders and clinicians treat patients. 

They also hope their results will spur car safety improvements. Safety equipment was originally designed with male bodies in mind, researchers noted. As such, women in the front seat are more likely to be trapped in crashed cars and to suffer severe or fatal injuries.

These factors prompted the study, which was published March 14 in the journal Frontiers in Public Health.

“We hope we can delineate the impact of sex on crash injury further, so that vehicle safety engineering can consider important male and female body differences in their design, and that they provide insight for legislation and regulations as needed for equity in car safety design,” Cronn said in a journal news release.

Researchers noted that their findings had some limitations. For one, the data they used did not include diastolic blood pressure data, which would make shock index calculations more precise. 

Also not known were vehicle size, type of crash and complete information on crash dynamics. Researchers said these factors might have shed even more light on sex differences in crashes.

More information

The National Library of Medicine has a primer on shock.

SOURCE: Frontiers, news release, March 15, 2024

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