Abstract P113: Correlation between Respiration-related Systolic Arterial Pressure Variability and Amount of Blood Loss during Controlled Hemorrhagic Shock in Rat Model
Objectives: Practical indicator reflecting circulatory blood volume is needed for the treatment of severe hemorrhagic shock. It has been reported that systolic arterial pressure (SAP) variations allow the assessment of cardiac preload. Thus, we aim to investigate whether respiration-related SAP fluctuation is correlated with the amount of blood loss during controlled hemorrhagic shock.
Methods: Fifteen Wistar male rats (214±9g) were anesthetized with sodium pentobarbital intraperitoneally (1.5 mg/kg). Spontaneous respiration was kept in each animal during the study. The left carotid artery was cannulated to draw blood continuously (0.1 ml/min) to induce hemorrhagic shock. SAP was continuously recorded and analyzed by wavelet transform using PC soft ware (FlucletTM, Dainippon-Sumitomo Pharma Co., Ltd., Osaka, Japan). The power spectra were quantified into high-frequency components (HF: 0.74 –2.00 Hz) reflecting the respiration-related SAP fluctuation. Respiratory movement was recorded by a pressure sensor placed under the body.
Results: During controlled hemorrhagic shock (shed blood volume 0 min: 0 ml, 20 min: 2.0ml, 40 min: 4.0 ml, 60 min: 6.0 ml), SAP and HF were gradually decreased (SAP 0 min: 107±14 mmHg, 20min: 70±9, 40min: 57±11, 60min: 48±9, repeated ANOVA P<0.01, HF: 0.92±0.53 ms/Hz0.5, 0.62±0.27, 0.58±0.23, 0.40±0.25, P<0.01), and respiratory rate (RR) was increased (84±13/min, 97±18, 100±17, 98±20, P<0.01). HF was significantly correlated with shed blood volume, SAP, and RR (r=−0.48, P<0.01, r=0.64 P<0.01, r=−0.23 P=0.02, respectively).
Conclusions: During controlled hemorrhagic shock in anesthetized rats, respiration-related SAP fluctuation is well correlated with shed blood volume and SAP. These results may provide a novel possible approach to the non-invasive estimation for blood volume status during hemorrhagic shock.