Retrospective analysis of the effects of hypocalcemia in severely injured trauma patients.

BACKGROUND: It has been suggested that the Lethal Triad be modified to include hypocalcemia, coined as the Lethal Diamond. Hypocalcemia in trauma has been attributed to multiple mechanisms, but new evidence suggests that traumatic injury may result in the development of hypoCa independent of blood transfusion. We hypothesize that hypocalcemia is associated with increased blood product requirements and mortality. METHODS: A retrospective study of 1,981 severely injured adult trauma patients from 2016 to 2019. Ionized calcium (iCa) levels were obtained on arrival and subjects were categorized by a threshold iCa level of 1.00 mmol/L and compared. Univariable and multivariable logistic regression analysis was performed. RESULTS: The hypocalcemia (iCa <1.00 mmol/L) group had increased rate of overall (p = 0.001), 4-hr (p = 0.007), and 24-hr (p = 0.003) mortality. There was no difference in prehospital transfusion volume between groups (p = 0.25). Hypocalcemia was associated with increased blood product requirements at 4 h (p <0.001), 24 h (p <0.001), and overall hospital length of stay (p <0.001). Logistic regression analysis showed increased odds of 4-hour mortality (OR 0.077 [95 % CI 0.011, 0.523], p = 0.009) and 24-hour mortality (OR 0.121 [95 % CI 0.019, 0.758], p = 0.024) for every mmol/L increase in iCa. CONCLUSIONS: This study shows the association of hypoCa and traumatic injury. Severe hypoCa was associated with increased odds of early and overall mortality and increased blood product requirements. These results support the need for future prospective trials assessing the role of hypocalcemia in trauma.

The impact of prehospital whole blood on hemorrhaging trauma patients: A multi-center retrospective study.

BACKGROUND: Whole blood (WB) use has become increasingly common in trauma centers across the United States for both in-hospital and prehospital resuscitation. We hypothesize that prehospital WB (pWB) use in trauma patients with suspected hemorrhage will result in improved hemodynamic status and reduced in-hospital blood product requirements. METHODS: The institutional trauma registries of two academic level I trauma centers were queried for all patients from 2015-2019 who underwent transfusion upon arrival to the trauma bay. Patients who were dead on arrival or had isolated head injuries were excluded. Demographics, injury and shock characteristics, transfusion requirements, including massive transfusion protocol (MTP) (>10 U in 24 hours) and rapid transfusion (CAT3+) and outcomes were compared between pWB and non-pWB patients. Significantly different demographic, injury characteristics and pWB were included in univariate followed by stepwise logistic regression analysis to determine the relationship with shock index (SI). Our primary objective was to determine the relationship between pWB and improved hemodynamics or reduction in blood product utilization. RESULTS: A total of 171 pWB and 1391 non-pWB patients met inclusion criteria. Prehospital WB patients had a lower median Injury Severity Score (17 vs. 21, p < 0.001) but higher prehospital SI showing greater physiologic disarray. Prehospital WB was associated with improvement in SI (-0.04 vs. 0.05, p = 0.002). Mortality and (LOS) were similar. Prehospital WB patients received fewer packed red blood cells, fresh frozen plasma, and platelets units across their LOS but total units and volumes were similar. Prehospital WB patients had fewer MTPs (22.6% vs. 32.4%, p = 0.01) despite a similar requirement of CAT3+ transfusion upon arrival. CONCLUSION: Prehospital WB administration is associated with a greater improvement in SI and a reduction in MTP. This study is limited by its lack of power to detect a mortality difference. Prospective randomized controlled trials will be required to determine the true impact of pWB on trauma patients. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Risk factors for massive transfusion in obstetrical hemorrhage and consideration of a whole blood program.

BACKGROUND: Postpartum hemorrhage (PPH) is one of the leading causes of obstetric complications. The goal of this study was to identify risk factors for obstetric (OB) massive transfusion (MT) and determine the feasibility of developing a low-titer group O RhD-positive whole blood (LTO + WB) protocol for OB hemorrhage. STUDY DESIGN AND METHODS: A retrospective study of OB patients who received transfusion within 24 h. MT patients were those who received >3 U of pRBC within 1 h or > 10 U in 24 h. Patient demographics, OB history, comorbidities, blood type, antibody status, and known risk factors for PPH and maternal-fetal outcomes were compared. Logistic regression was used for univariate and multivariate analyses. RESULTS: Of the 610 transfused OB patients, 12.0% (n = 73) required MT. Groups were well matched for body mass index (BMI), maternal comorbidities, and history of spontaneous vaginal deliveries. The incidence of the previous cesarean section was higher in the MT group. Exactly 93.9% of patients were RhD-positive and 3.77% of all patients possessed an antibody on pretransfusion testing. Patients with MT had a longer length of stay (LOS), higher rate of intensive care unit (ICU) admission, fetal death, and hysterectomy. Multivariate analysis found age >35, PPH, placenta percreta, accreta, and increta to be significant (p < .05) risk factors for MT. DISCUSSION: Patients over 35 years and those with abnormal placentation are at increased risk of requiring MT. With a time to delivery of 2 days, potential MT patients can be identified early, and with a 94% rate of RhD-positive+, they are eligible to receive low-titer O whole blood (LTOWB) providing hemostatic resuscitation with reduced donor exposure.

The effects of hypocalcemia in severely injured pediatric trauma patients.

INTRODUCTION: The role of calcium is ubiquitous in human physiology. Emerging evidence suggests that the lethal triad be revised to include hypocalcemia (hypoCa) and thus be known as the lethal diamond . There are data showing that traumatic injury may result in hypoCa independent from the mechanism of calcium chelation by citrate-based blood preservatives. Minimal literature exists analyzing the role of hypoCa in pediatric trauma patients. We hypothesize that there is an independent association of hypoCa with increased blood product requirements and mortality. METHODS: A retrospective cohort study of severely injured pediatric trauma patients was conducted. Trauma registry data were collected from January 2016 to August 2021. Ionized calcium (iCa) levels were obtained from arrival blood draws. Subjects were categorized into two groups by a threshold iCa level of 1.00 mmol/L and compared. Shock Index Pediatric Adjusted scores were used to adjust for age-specific differences in vital signs. RESULTS: A total of 142 patients were compared, of which 46.5% were hypocalcemic (iCa <1.00 mmol/L). Patients were well matched in terms of demographics and injury severity. The hypocalcemic group had lower systolic blood pressure and a higher percentage of Shock Index Pediatric Adjusted-positive patients. Weight-adjusted transfusion volumes were significantly higher in the hypocalcemic group at both the 4-hour and 24-hour time points without a difference in prehospital transfusion requirements. There was no observed difference in early or in-hospital mortality. CONCLUSION: This study contributes to the body of literature regarding the association between hypoCa and traumatic injury in the pediatric population. Hypocalcemia was associated with increased blood product requirements without a difference in prehospital transfusion requirements, suggesting a possible independent association. Further prospective studies are needed to better understand this relationship. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

Prehospital whole blood reduces early mortality in patients with hemorrhagic shock.

BACKGROUND: Low titer O+ whole blood (LTOWB) is being increasingly used for resuscitation of hemorrhagic shock in military and civilian settings. The objective of this study was to identify the impact of prehospital LTOWB on survival for patients in shock receiving prehospital LTOWB transfusion. STUDY DESIGN AND METHODS: A single institutional trauma registry was queried for patients undergoing prehospital transfusion between 2015 and 2019. Patients were stratified based on prehospital LTOWB transfusion (PHT) or no prehospital transfusion (NT). Outcomes measured included emergency department (ED), 6-h and hospital mortality, change in shock index (SI), and incidence of massive transfusion. Statistical analyses were performed. RESULTS: A total of 538 patients met inclusion criteria. Patients undergoing PHT had worse shock physiology (median SI 1.25 vs. 0.95, p < .001) with greater reversal of shock upon arrival (-0.28 vs. -0.002, p < .001). In a propensity-matched group of 214 patients with prehospital shock, 58 patients underwent PHT and 156 did not. Demographics were similar between the groups. Mean improvement in SI between scene and ED was greatest for patients in the PHT group with a lower trauma bay mortality (0% vs. 7%, p = .04). No survival benefit for patients in prehospital cardiac arrest receiving LTOWB was found (p > .05). DISCUSSION: This study demonstrated that trauma patients who received prehospital LTOWB transfusion had a greater improvement in SI and a reduction in early mortality. Patient with prehospital cardiac arrest did not have an improvement in survival. These findings support LTOWB use in the prehospital setting. Further multi-institutional prospective studies are needed.