UTILIZING SPECTRAL TRANSCRANIAL DOPPLER TO CHARACTERIZE CEREBRAL HEMODYNAMICS IN A NON-HUMAN PRIMATE (RHESUS MACAQUE)
Abstract
Background: Hemodynamic resuscitation methods are employed to attenuate tissue hypoxia and maintain circulatory homeostasis during hemorrhagic shock. There is increasing advocacy for permissive hypotension resuscitative methods to prevent exsanguination. While data supports this strategy to decrease hemorrhage, questions remain regarding its physiologic effect on the brain. Transcranial Doppler (TCD) ultrasonography is a non-invasive modality that can be used to monitor cerebral perfusion during resuscitation. Utilizing a non-human primate (NHP) model, our goal was to use TCD ultrasonography to characterize normal cerebral hemodynamics, allowing for future comparative analyses of cerebral hemodynamics in animal models of polytraumatic hemorrhagic shock. Materials and Methods: Concurrent with an ongoing NHP protocol, the ophthalmic artery (OA) was insonated to establish baseline TCD values. A transorbital acoustic window was used, imaging was obtained with a 2.0 MHz transducer probe. OA was chosen as the transtemporal window for middle cerebral artery (MCA) resulted in suboptimal waveforms. Results: The following TCD results represent the mean standard deviation, n = 10. Pulsatility index (1.66+-0.33), mean flow velocity (MFV) (21.64+-5.48 cm/s), peak systolic velocity (45.46+-5.48 cm/s), end diastolic velocity (9.84+-3.91 cm/s) and resistance index (0.79+-0.08). Conclusions: We discovered that Rhesus macaques are absent of an adequate transtemporal acoustic window for MCA insonation, and normal resting OA MFV pressure in NHPs mimics reported OA MFV in humans. This data is foundational for our future studies to evaluate cerebral hemodynamics during hemorrhage and the degrees of severity in hemorrhagic shock. Our future goals include the utilization of TCD technology to elucidate a safety threshold for permissive hypotensive resuscitation or aggressive fluid resuscitation as it pertains to cerebral blood flow.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 16, 2017
- Accession Number
- AD1039543
Entities
People
- Forest R. Sheppard
- G. Iii A. Pratt
- Jacob J. Glaser
Organizations
- Naval Medical Research Unit—San Antonio