Do early ionized calcium levels really matter in trauma patients?

Area of Science:

• Trauma research
• Critical care medicine
• Biochemistry

Background:

• Prognostic indicators in trauma care typically include age, injury severity, and base deficit.
• This study explores the prognostic value of ionized calcium (iCa) levels upon emergency department arrival.

Purpose of the Study:

• To investigate the relationship between initial ionized calcium (iCa) levels and injury severity, acidosis, hypotension, and mortality in trauma patients.
• To compare the predictive power of iCa with established markers like base deficit.

Main Methods:

• Retrospective analysis of adult trauma team activations from 2000-2002.
• Stratification of patients into groups based on initial iCa levels (< or = 1 mmol/L vs. > 1 mmol/L).
• Examination of associations between iCa and various injury severity scores, demographic factors, shock parameters, resource utilization, and mortality.

Main Results:

• Lower iCa (< or = 1 mmol/L) was significantly associated with increased mortality (26.4% vs. 16.7%) and shorter time to death.
• Initial low iCa levels independently predicted mortality and were linked to prehospital hypotension (systolic blood pressure < 90 mmHg).
• The incidence of base deficit was higher in patients with low iCa, but low iCa emerged as a stronger mortality predictor.

Conclusions:

• Initial low ionized calcium is a significant predictor of mortality in trauma patients, surpassing base deficit in predictive accuracy.
• Low iCa is associated with prehospital hypotension, irrespective of injury severity score or sampling time.
• The observed association between base deficit and iCa warrants further investigation due to the complex interplay between acidosis and calcium binding.