(O-L2) Does Hyperglycemia Predict Hypocalcemia in Critically Injured Trauma Patients?

Objectives: The purpose of the current study is to evaluate if a relationship exists between glucose and ionized calcium (iCa) and whether specific glucose levels can determine a predictive threshold for identification of hypocalcemia (iCa < 4.40 mg/dL) and severe hypocalcemia (iCa < 3.60 mg/dL).

Background: Hypocalcemia is frequently encountered in severely injured trauma patients and is associated with increased mortality. Alongside acidosis, hypothermia, and coagulopathy, hypocalcemia forms a key component of the “lethal diamond” [1,2]. Hyperglycemia in critically ill trauma patients is also associated with increased morbidity and mortality, potentially reflecting a hypermetabolic stress response [3,4,5]. However, calcium is also important in insulin secretion [6]. Early identification of hypocalcemia is important in the management of critically ill trauma patients. Although point-of-care testing devices are available, these devices are not typically available on ground EMS (GEMS) units. However, almost every GEMS unit has a glucometer.

Methods: This study was an IRB-approved retrospective chart review of trauma patients presenting to the St Marys Hospital emergency department by GEMS and Helicopter EMS (HEMS) between 1/1/2011 – 12/31/2021. Inclusion criteria included age > 18, acute traumatic injury, primary transport from the scene, severe trauma (prehospital hypotension (SBP < 90 mm Hg) and shock index > 1), and trauma service evaluation. First recorded laboratory values upon arrival in the emergency department were abstracted into an Excel database.

Results: A total of 10,974 trauma patients were transported during the study period, of which 96 GEMS and 40 HEMS were included in the final cohort. One hundred and twenty two patients (89.7%) sustained blunt trauma. Overall mortality was 16.9%; no difference was noted HEMS vs GEMS (p = 0.54, Chi Square). Mean (SD) iCa was 4.32 (0.66) mg/dL; 4.44 (0.67) GEMS vs 4.11 (0.60) HEMS (p = 0.02, T test). Forty patients (29.4%) were hypocalcemic on arrival while 13 (9.6%) were severely hypocalcemic: HEMS patients were more likely to be hypocalcemic (p < 0.001, Chi Square) and severely hypocalcemic (p = 0.06, Chi Squared). Mean (SD) serum glucose was 185.77 (83.12) mg/dL; 157.15 (71.34) GEMS vs 219.69 (78.91) HEMS (p = 0.08, T test). The best fit line for iCa versus Glucose was [iCa] = -0.0036[Glc] + 4.9939. Using this best fit line, serum glucose of 200 mg/dL corresponds with iCa of 4.27 mg/dL (95% CI: 3.98 – 4.56). Glucose cut-offs for hypocalcemia and severe hypocalcemia are 166 mg/dL (95% CI: 118 - 276) and 387 mg/dL (95% CI: 276 - 648) respectively. Pearson’s correlation coefficient is -0.46.

Conclusions: Although this study utilized a small, regional, retrospective cohort of severe trauma patients and analyzed laboratory values determined in the ED, the data suggest that use of a glucometer may permit early identification of hypocalcemia in these patients, thereby providing an opportunity to intervene in the prehospital environment. Further studies are required to validate the results of this study.

References (Optional): 1. Wray JP, Bridwell RE, Schauer SG, Shackelford SA, Beberta VS, Wright FL, Bynym J, Long B. The Diamond of Death: Hypocalcemia in Trauma and Resuscitation. Am J Emerg Med 2021; 41: 104-109.
2. Ditzel RM, Anderson JL, Eisenhart WJ, Rankin CJ, DeFeo DR, Oak S, Siegler J. Transfusion- and Trauma-Induced Hypocalcemia: Is it Time to Change the Lethal Triad to the Lethal Diamond? J Acute Care S
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4. Di Luzio R, Dusi R, Mazzotti A, Petroni ML, Marchesini G, Bianchi G. Stress Hyperglycemia and Complications Following Traumatic Injuries in Individuals with/without Diabetes: The Case of Orthopedic Surgery. Diabetes, Metabol Syndrome Obesity 2020; 13: 9 – 17.
5. Laird AM, Miller PR, Kilgo PD, Meredith JM, Chang MC. Relationship of Early Hyperglycemia to Mortality in Trauma Patients. J Trauma 2004; 56: 1058-1062.
6. Levine M, Boyer EW, Pozner CN, Geib A-J, Thomsen T, Mick N, Thomas SH. Assessment of Hyperglycemia after Calcium Channel Blocker Overdoses Involving Diltiazem or Verapamil. Crit Care Med 2007; 35: 2071-2075

Funding (Optional): No funding