Page 48 - JSOM Summer 2023

TABLE 3 Secondary Outcomes impact of a calcium supplement prior to blood transfusion is
Hypocalcemia Entire Cohort, poorly defined. 18
Variables Group, n (%) n (%)
Abnormal INR , n (%) 25 (8.7) 32 (11.2) This retrospective analysis completed at a single-center, level I
1
INR >1.5, n (%) 6 (2) 9 (3) trauma, and SOCM training facility had similar outcomes in
Acidosis , n (%) 22 (15) 34 (23) comparison to previous literature, in which ionized calcium
2
Severe acidosis, pH <7.2 1 (<1) 2 (1.4) was utilized (Table 4). Of the 370 trauma patients included
3
Elevated lactic , n (%) 17 (6.7) 21 (8) in the final analysis, 189 (51%) patients had an iCa level of
Hypothermia 6 (1.7) 9 (2.5) <1.13mmol/L, and among these patients, only two patients ex-
4
(Temp. <35°C), n (%) perienced severe hypocalcemia. These patients did not receive
Normal lab ranges: INR 0.8–1.13, PT 9.0–13.5, iCa (mmol/L) 1.13– any blood products prior to their ED arrival. Interestingly, the
1.32, pH 7.36–7.46, and lactic acid 0.4–2.00. data of this cohort also showed that nine (90%) patients in the
1 n = 286 for PT and INR; n = 147 for pH; n = 253 for lactic acid; gunshot wound group experienced hypocalcemia, as indicated
3
2
4 n = 358 for temperature. in Table 2. Zero patients in the GSW group received a blood
transfusion, and these patients were normotensive in the ED.
FIGURE 2 ISS distribution of hypocalcemic trauma patients.
Hypovolemic shock could be one of the causes of hypocalce-
mia. However, a larger sample size is needed to confirm this
relationship.
Other elements of the Diamond of Death—coagulopathy, ac-
idosis, and hypothermia—were also assessed in this cohort.
Only six (2%) hypocalcemic patients had acute traumatic co-
agulopathy defined as INR >1.5 (Table 3). Our findings differ
from those found by Vasudeva et al. This group of authors
reported that there was an independent association between
hypocalcemia and acute traumatic coagulopathy, and INR
levels were 1.3 and 1.7 in normocalcemic and hypocalcemic
groups, respectively, with a p-value of 0.03. With respect to
12
acidosis, 22 (15%) of the hypocalcemic patients had pH <7.36
with one case of severe acidosis. Vivien et al. reported a di-
ISS = Injury Severity Score. rect relationship between iCa level and arterial pH level with
a correlation coefficient of 0.76. Finally, six (1.7%) patients
13
Discussion in the hypocalcemic group had initial temperature of <35°C.
Unfortunately, the direct relationship between calcium and hy-
Hypocalcemia was not considered a major contributing factor pothermia is not clearly understood.
in trauma-related deaths until recently. In 2019, the Trauma
Triad was updated to include hypocalcemia and has been re- Recently, Blackney et al. and Leech et al. recommend starting
named the Lethal Diamond. It is crucial to understand how empiric calcium treatment in hypovolemic trauma patients in
1,2
hypocalcemia interacts with other components of the Lethal whom blood transfusion is anticipated. 15,16 However, there is
Diamond. First, calcium is a necessary ion in hemostasis and insufficient evidence to support the use of supplement calcium
coagulation cascade. It plays a significant role in platelet ad- in trauma patients prior to blood transfusion. In our cohort,
14
hesion and intrinsic function of factors II, VII, IX, X, and pro- only 14 (7.4%) patients required blood transfusion upon their
teins C and S in the coagulation cascade. Second, declining presentation to the ED. Literature has shown that mortality is
calcium level results in lowering pH, which leads to increased higher in patients with an abnormal calcium level either from
clot formation time. Third, hypothermia decreases the metab- primary injury or overcorrection. Due to the lack of evidence
18
olism of citrate in the liver, which contributes to accumulation describing the relationship of calcium dysregulation in severely
of citrate and subsequent hypocalcemia. A healthy liver can injured patients, the impact of transfusion and calcium supple-
metabolize approximately 3g of citrate every 5 minutes. How- mentation, empiric calcium treatment in hypovolemic trauma
ever, liver injuries due to trauma or critical illness reduce ci- patients should not be initiated in the prehospital setting until
trate metabolism, and citrate begins to accumulate and chelate more evidence is available.
with free ionized calcium in serum, leading to hypocalcemia. 2
Numerous studies over the past 30 years have observed high This study has several limitations. First, this is a retrospective
mortality rates in trauma patients with hypocalcemia, and the and observational study completed at a single-center facility.
correlation of blood transfusion and hypocalcemia in hypo- Second, laboratory ranges were preset ranges according to the
volemic trauma patients is well-established. However, the facility and may vary in comparison to other level I trauma
5–9
relationship of calcium hemostasis in severe injuries and the centers. This study was completed during winter months,

TABLE 4 Ionized Hypocalcemia in Trauma Patients Among Different Studies
Vivien et al. 13 Cherry et al. 11 Magnotti et al. 10 Webster et al. 14 Vasudeva et al. 12 This study
(2005) (2006) (2011) (2016) (2019) (2022)
Sample Size (n) 212 396 591 55 226 370
Study Site France Pennsylvania, USA Tennessee, USA UK Australia Missouri, USA
Hypocalcemia, % 74 23 56 55 50 51

46 | JSOM Volume 23, Edition 2 / Summer 2023