title: Hypocalcemia in trauma patients receiving massive transfusion.
abstract: BACKGROUND
  Massive transfusion protocol (MTP) is increasingly used in civilian trauma resuscitation. Calcium is vital for coagulation, but hypocalcemia commonly occurs during massive transfusion due to citrate and serum calcium chelation. This study was conducted to determine the incidence of hypocalcemia and severe hypocalcemia in trauma patients who receive massive transfusion and to compare characteristics of patients with severe versus nonsevere hypocalcemia.
  
  
  METHODS
  This was a retrospective study of trauma patients who received massive transfusion between January 2009 and November 2013. The primary outcome was the incidence of hypocalcemia (ionized calcium [iCa] < 1.12 mmol/L) and severe hypocalcemia (iCa < 0.90 mmol/L). Secondary outcomes included calcium monitoring, calcium replacement, and correction of coagulopathy.
  
  
  RESULTS
  There were 156 patients included; 152 (97%) experienced hypocalcemia, and 111 (71%) had severe hypocalcemia. Patients were stratified into iCa ≥ 0.90 (n = 45) and iCa < 0.90 (n = 111). There were no differences in demographics or baseline laboratories except the severe hypocalcemia group had higher baseline activated partial thromboplastin time (29.7 [23.7-50.9] versus 25.8 [22.3-35.9], P = 0.003), higher lactic acid (5.8 [4.1-9.8] versus 4.0 [3.1-7.8], P = 0.019), lower platelets (176 [108-237] versus 208 [169-272], P = 0.003), and lower pH (7.14 [6.98-7.28] versus 7.23 [7.14-7.33], P = 0.019). Mortality was higher in the severe hypocalcemia group (49% versus 24%, P = 0.007). Patients in the iCa < 0.90 group received more blood products (34 [23-58] versus 22 [18-30] units, P < 0.001), and calcium chloride (4 [2-7] versus 3 [1-4] g, P = 0.002), but there was no difference in duration of MTP or final iCa. Neither group reached a median iCa > 1.12.
  
  
  CONCLUSIONS
  Hypocalcemia is common during MTP, and vigilant monitoring is warranted. Research is needed to effectively manage hypocalcemia during massive transfusion.
authors.affiliation: Department of Pharmacy, Orlando Regional Medical Center, Orlando, Florida. Electronic address: amanda.giancarelli@orlandohealth.com.
authors.forename: Amanda
authors.initials: A
authors.lastname: Giancarelli
authors.affiliation: Department of Pharmacy, Orlando Regional Medical Center, Orlando, Florida.
authors.forename: Kara L
authors.initials: KL
authors.lastname: Birrer
authors.affiliation: Department of Surgical Education, Orlando Regional Medical Center, Orlando, Florida.
authors.forename: Rodrigo F
authors.initials: RF
authors.lastname: Alban
authors.affiliation: Department of Pharmacy, Orlando Regional Medical Center, Orlando, Florida.
authors.forename: Brandon P
authors.initials: BP
authors.lastname: Hobbs
authors.affiliation: Department of Pharmacy, Orlando Regional Medical Center, Orlando, Florida. Electronic address: xi.liu@flhosp.org.
authors.forename: Xi
authors.initials: X
authors.lastname: Liu-DeRyke
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001803:Blood Transfusion / Q000379:methods; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D012720:Severity of Illness Index; D065227:Transfusion Reaction; D014947:Wounds and Injuries / Q000628:therapy*; D055815:Young Adult
keywords: Blood coagulation; Blood transfusion; Calcium; Hypocalcemia; Resuscitation; Trauma