Objective—To evaluate the usefulness of Doppler ultrasonography as a method to assess changes in digital vascular dynamics in horses with systemic inflammatory response syndrome (SIRS) or laminitis.
Animals—42 adult Andalusian horses.
Procedures—Group 1 included 9 healthy horses, group 2 included 19 horses with SIRS without (n = 9) or with (10) a palpable increase in digital pulse intensity, and group 3 included 14 horses with laminitis without (8) or with (6) radiographic evidence of rotation or distal displacement (sinking) of the third phalanx. Qualitative spectrum characteristics and quantitative Doppler measurements of the lateral palmar digital artery were obtained for horses in each group.
Results—4 spectra, characterized by a positive systolic peak followed by several positive diastolic peaks, were observed in group 1 horses, group 2 horses, and group 3 horses that lacked radiographic changes. In the group 3 horses that had radiographic changes, laminar blood flow was detected. Diameter of the lateral palmar digital artery was significantly larger in the group 3 horses than in the group 2 horses; blood flow was significantly higher in the group 2 horses that had an increase in digital pulse intensity than in the group 2 horses without an increase in digital pulse intensity; velocity-time integral and acceleration time were significantly lower in group 3 horses, compared with group 2 horses.
Conclusions and Clinical Relevance—Results suggested that Doppler ultrasonography may be a useful complementary tool to detect digital blood flow changes of horses with SIRS, especially if they have a palpable increase in digital pulse intensity, or laminitis.
Objective—To compare measurements of blood flow
in the common femoral artery obtained by duplex
Doppler ultrasonography (DDU) and a reference ultrasonic
transit-time flow (TTF) method and to examine
the impact of Doppler spectral waveform measurement
techniques on volumetric estimates.
Animals—5 healthy female pigs.
Procedure—Femoral arterial blood flow was measured
simultaneously in anesthetized pigs by use of a
TTF probe (left femoral artery) and transcutaneous
DDU (right femoral artery). A range of flow states was
induced pharmacologically by using xylazine,
bradykinin, dobutamine, and isoflurane. Volumetric
blood flow was calculated from DDU waveforms,
using the product of the flow velocity integral (FVI),
the cross-sectional vessel area, and heart rate. Three
calculations of FVI were obtained by manually tracing
the Doppler spectral envelopes at the outer envelope,
the modal, and the inner envelope of the spectral dispersion
pattern. Data analysis included calculation of
Pearson correlation coefficients and Bland-Altman
limits of agreement.
Results—Blood flow measured by DDU was more
closely correlated with TTF measurements when the
modal or inner envelope tracing method was used
( r, 0.76 and 0.78; limits of agreement, –100 to 54.2
and –48.5 to 77.0 mL/min, respectively). Limits of
agreement for the outer envelope tracing method
were –238.5 to 64 mL/min.
Conclusion and Clinical Relevance—Transcutaneous
DDU is a reliable noninvasive technique for
measuring blood flow in the femoral artery of pigs
over a range of flow states. Tracing the inner envelope
of the Doppler spectral dispersion pattern provided
the best estimate of blood flow in this study.
(Am J Vet Res 2003;64:43–50)