Abstract:

Objective

To explore the feasibility and stability of an improved puncture method under multimodal portable ultrasound guidance to prepare a pig iliac artery rupture and bleeding model.

Methods

Six Bama miniature pigs (35-45 kg) were utilized.Under ultrasound guidance, a venous catheter was inserted into the right internal jugular vein for intraoperative fluid administration and anesthesia maintenance.A PiCCO catheter was placed via the common carotid artery to monitor baseline vital signs (blood pressure, heart rate, and body temperature).A heparinized saline solution (12500 units heparin sodium +100 ml saline) was injected around the iliac artery puncture target under portable ultrasound guidance to achieve local heparinization.Subsequently,a disposable biopsy needle was used to puncture the iliac artery under real-time ultrasound guidance for model establishment.Vital signs were continuously recorded before and after modeling.At 0, 10, 20, and 30 minutes post-modeling, multiple portable ultrasound modalities [grayscale ultrasound, color Doppler ultrasound (CDUS),spectral Doppler ultrasound (PW), contrast-enhanced ultrasound (CEUS), and microvascular flow imaging (MFI)]were employed for qualitative and localization diagnosis of active iliac artery hemorrhage, with diagnostic efficacy evaluated.Additionally, cross-sectional area and hemodynamic parameters (peak systolic velocity (PSV), enddiastolic velocity (EDV), mean velocity (Vmean), resistance index (RI), and pulsatility index (PI)) at 1-1.5 cm distal to the puncture site were monitored.Animals were euthanized after 30 minutes for anatomical validation.Paired t-tests were used to compare pre- and post-modeling hemodynamic parameters.The chi-square test (χ² test) and Bonferroni correction method were used to compare the diagnostic efficacy of different imaging modalities between groups.

Results

The modeling in all the six experimental animals was successfully completed at one time.After modeling, the systolic blood pressure, diastolic blood pressure, mean arterial pressure, and body temperature were all lower than those before modeling [(100.33±4.41) mmHg vs (146.17±5.19) mmHg, (70.33±4.97)mmHg vs (115.67±16.51) mmHg, (80.00±2.89) mmHg vs (118.33±3.88) mmHg, and (36.45±0.38)°C vs(37.41±0.41)°C, respectively], and the heart rate was faster than that before modeling [(111.50±2.74) beats/min vs (79.83±6.65) beats/min]; all the differences were statistically significant (t=22.469, 6.657, 17.068, 4.503,and -10.162, P＜0.001, =0.001, =0.001, =0.006, and ＜0.001, respectively).At 0 minutes and 10 minutes after modeling, there were no statistically significant differences in the qualitative and localization diagnosis of active iliac artery bleeding among contrast-enhanced ultrasound (CEUS) combined with microflow imaging (MFI), color Doppler ultrasound (CDUS), CEUS, and MFI (all P＞0.05).At 20 minutes after modeling, the efficacy of CEUS combined with MFI in diagnosing active iliac artery bleeding and locating the bleeding site was significantly higher than that of CDUS (P=0.015), but there were no statistically significant differences when compared with CEUS and MFI (P＞0.05).At 30 minutes after modeling, the efficacy of CEUS combined with MFI in diagnosing active iliac artery bleeding and locating the bleeding site was significantly higher than that of CDUS and MFI (P=0.015 and 0.015, respectively), but there was no statistically significant difference when compared with CEUS (P＞0.05).Meanwhile, the cross-sectional area of the diameter at the distal end of the iliac artery puncture site was smaller than that before modeling [(0.13±0.08)cm² vs (0.38±0.17)cm²], and the systolic blood flow velocity, diastolic blood flow velocity, mean blood flow velocity, resistance index, and pulsatility index at the distal end of the iliac artery puncture site were lower than those before modeling [(65.24±15.76)cm/s vs (115.53±11.25)cm/s, (11.23±5.45)cm/s vs (-21.36±2.45)cm/s, (21.95±11.36)cm/s vs (75.27±12.35)cm/s, (0.74±0.16) vs (1.08±0.25), and(1.13±0.28) vs (1.81±0.36), respectively]; all the differences were statistically significant (t=8.510, -17.608,11.137, 8.470, and 7.605, P＜0.001, ＜0.001, ＜0.001, ＜0.001, and =0.001, respectively).The puncture rupture site could be shown in the gross specimens of the iliac artery after dissection.

Conclusion

The modeling of local heparinized iliac artery puncture bleeding guided by multimodal portable ultrasound is accurate and stable, and can be used to accurately evaluate the bleeding status of the iliac artery in real time, providing an animal model basis for the treatment of vascular trauma bleeding at the junction.

Key words: Multimodal portable ultrasound, Pig, Iliac artery bleeding, Model preparation, Local heparinization