Isolated Brain Trauma in Cats Triggers Rapid Onset of Hypovolemia.
BACKGROUND
Hemodynamic instability responsive to fluid resuscitation is common after a traumatic brain injury (TBI), also in the absence of systemic hemorrhage. The present study tests if an isolated severe TBI induces a decrease in plasma volume (PV).


METHODS
The study was performed in three groups of anesthetized and tracheostomized male cats (n = 21). In one group (n = 8), the cats were prepared with a cranial borehole (10 mm i.d) used to expose the brain to a fluid percussion brain injury (FPI) (1.90-2.20 bar), and two smaller cranial boreholes (4 mm i.d) for insertion of an intracranial pressure (ICP) and a microdialysis catheter. To differentiate the effect of FPI from that of the surgical preparation, a sham group was exposed to the same surgical preparation but no FPI trauma (n = 8). A control group had no brain trauma and no surgical preparation (n = 5). PV was determined by a125I-albumin dilution technique. PV, electrolytes, pH, BE (base excess), hematocrit (Hct), PaO2, and PaCO2were measured at baseline and after 3 h. Mean arterial pressure (MAP) was measured continuously. ICP was measured in the FPI and the sham group.


RESULTS
In the FPI group, PV decreased by 11.2 mL/kg from 31.7 mL/kg (p < 0.01) with a simultaneous increase in Hct and decrease in pH. In the sham group, PV decreased by 5.7 mL/kg from 32.7 mL/kg (p < 0.01). The control group showed no PV reduction.


CONCLUSIONS
The results support that an isolated severe head trauma triggers a significant and rapid reduction in PV, most likely due to vascular leak.
Department of Clinical Sciences, Anesthesiology and Intensive Care, Helsingborg Hospital, Lund University, Lund, Sweden.|Department of Clinical Sciences, Anesthesiology and Intensive Care, Lund University Hospital, Lund University, 22185, Lund, Sweden.
Peter
P
Bentzer
Department of Clinical Sciences, Anesthesiology and Intensive Care, Lund University Hospital, Lund University, 22185, Lund, Sweden. per-olof.grande@med.lu.se.
Per-Olof
PO
Grände
D000818:Animals; D000070642:Brain Injuries, Traumatic / Q000097:blood*; D002415:Cats; D004195:Disease Models, Animal; D020896:Hypovolemia / Q000097:blood*; D008297:Male
Blood pressure; Fluid percussion trauma; Intracranial pressure; Plasma volume; Traumatic brain injury; Vascular leak