Page 56 - JSOM Fall 2018
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TABLE 2 Pre- and Posttransfusion Thromboelastogram Values
R (s) K (s) (°) M (mm) Lys30
a
BL T+60 BL T+60 BL T+60 BL T+60 BL T+60
Gravity 4.85 ± 2.3 4.2 ± 2.6 1.3 ± 0.6 1.3 ± 0.9 73.1 ± 7.4 74 ± 78.65 ± 5.3 81 ± 1.6 ± 1.1 1.3 ± 0.9
Pressure 5.65 ± 3.9 6 ± 1.7 1.7 ± 0.6 2.05 ± 0.1 69.25± 6.3 63.1 ± 2.3 73.05 ± 5.7 78.5 ± 4.0 1.35 ± 1.9 0.75 ± 1.1
bag
Belmont
Rapid 5.5 ± 3.0 6.1 ± 1.8 1.25 ± 0.8 1.2 ± 0.1 63.9 ± 7.7 60.7 ± 5.7 72.15 ± 7.5 79.9 ± 11.3 1.8± 0.1 1.9 ± 0.0
Infuser
Pushpull 6.35 ± 1.8 5.65 ± 4.3 1.6 ± 0.5 1.4 ± 0.8 66.05 ± 17.4 67.9 ± 42.9 76.2 ± 8.1 74.25± 56.5 0.85 ± 1.1 1.175 ± 1.3
Data are expressed as mean ± standard deviation. All n values based on two subjects.
α, measure of speed at which fibrin builds up and cross linking takes place; BL, baseline averages (three samples per subject); K, time taken to
achieve a certain level of clot strength; Lys30, degree of fibrinolysis; M , ultimate strength of the clot; R, time of latency from the start of the test
a
to initial fibrin formation; T+60, 60 minutes postinfusion (three samples per subject).
TABLE 3 Pulmonary Pathology Findings methodology differs in that we placed the IO access, flushed
Pulmonary 10mL of saline, and immediately began to transfuse. The pre
Arterial vious study delayed transfusion until 20 minutes after initial
Fat Emboli Fat Droplets/ IO insertion. Tactical Combat Casualty Care (TCCC) cur
(Histology or 10 HPF
Transfusion Strategy Oil Red O Stain) (Oil Red O Stain) rently advocates for gravity as an IO transfusion strategy. This
Gravity/pressure bag (UF) 0 18 practice is not supported by the findings of our pilot study.
TCCC instructors anecdotally have reported the resistance en
Gravity/pressure bag (LF) 0 15 countered before IO infusion as a “bone plug” that needs to
Belmont Rapid Infuser (UF) 0 6 be cleared. In our assessment of the bone matrix and effluent
34
Belmont Rapid Infuser (LF) 0 13 from the IO needle, we found no destruction of the matrix or
Pressure bag single site (UF) 0 6 marrow content that suggested a bone plug. However, findings
Pressure bag single site (LF) 0 26 in the literature support the TCCC recommendation of a 10–
Pressure bag double site (UF) 0 8 20mL flush of normal saline before infusion. The physiologic
Pressure bag double site (LF) 0 30 differences between systemic pressure and the pressure within
Pushpull (UF) 0 8 the marrow is likely causal in the resistance encountered be
6,35
Pushpull (LF) 0 22 fore IO transfusion, not a bone plug.
HPF, highpower field; LF, lower lung segment tissue sample; UF, up
per lung segment tissue sample. The major limitation of this pilot study is that it was not pow
ered to detect differences in flow rate or hematologic, osseous,
these juvenile animal models found no evidence of pulmonary or pulmonary complications among the transfusion strategies.
fat embolism. 8,10,11 In the current study, no evidence of pulmo We also lacked the logistic capability to evaluate rates of hemo
nary arterial fat embolism was found. However, in subjects in lysis or renal inflammation as performed in prior research. 8,17
each transfusionstrategy group, we did find varying degrees Future research should include plasmafree hemoglobin to test
of fat globules within the lung parenchyma. for rates of hemolysis and be powered to detect these differ
ences among transfusion strategies that vary by pressure and
Research has suggested IO transfusion may result in pulmo anatomic site. Another limitation is that results from a swine
nary fat embolism. 31–33 More recent research has described fat model may not directly translate to humans. However, swine
emboli from bone marrow intravasation, varying by degree of have very similar bone, cardiovascular, and blood physiology,
33
transfusion pressures. However, these studies did not differ and serve as an excellent model for this type of research. 15,17
entiate between pulmonary arterial fat emboli and presence We studied whole blood, not component therapy, which is
of fat globules within the lung parenchyma. This lack of dis more commonly used in DCR. The use of fresh, whole blood
5
tinction may account for the discrepancy within the literature. is currently isolated to military operations and the results may
Prior research noting fat emboli after IO transfusions has not not be directly translatable to civilian trauma practice, where
reported corresponding physiologic changes consistent with blood is transfused in a 1:1:1 ratio. Another limitation is
36
fat embolism syndrome. The only study following animals out that the timed flow rate period in this study was limited to
8
to 48 hours found no evidence of pulmonary fat emboli. Stud 5 minutes. Flow rates may decrease the longer the infusion
ies evaluating the effects of pressure IO transfusion strategies is studied. The data established in this study were on warm,
in skeletally mature pigs have found periosteal hemorrhage fresh autologous whole blood and pertain only to the device
27
and scattered bone debris among their subjects. We did not and insertion sites studied. These data may not translate di
replicate these findings in our small pilot study. rectly to cold, stored component therapy, other IO devices, or
insertion sites.
Our study also differs from prior studies that used platelet, fi
brinogen, or plasmafree hemoglobin levels to determine rates Conclusion
of hemolysis secondary to transfusion. 8,17 We cannot com
ment directly on hemolysis among our strategies. However, IO blood transfusion by gravity alone cannot meet the require
we evaluated for clotting ability by testing TEG values and ments for rDCR. The optimal strategy currently appears to be
found no physiologically significant difference among strate IO blood transfusion with a 10–20mL flush of normal saline
gies. We report a faster infusion rate than another study on IO followed immediately by transfusion under 300mmHg via a
17
blood transfusion in animals with higher bone density. Our pressure bag with a member of the resuscitation team inflating
54 | JSOM Volume 18, Edition 3 / Fall 2018
