Prevention Of Bone Cement Implantation Syndrome By Inferior Vena Cava Filter

Bone cement has contributed greatly since invented, especially to total/semi hip replacement of senior patients. It enhances the stability of prosthesis and strengthens the vertebral, establishing it irreplaceable role in prosthesis fixation. However, bone cement application could cause fatal side effects called bone cement implantation syndrome (BCIS), which manifests temporary hypotension, desaturation of blood oxygen, cardiac arrhythmia, pulmonary embolism, bleeding and asthma, etc. Sometimes it could lead to cardiac arrest and sudden death. It is important clinically to find an optimal way to prevent BCIS. Inferior vena cava filter (IVCF) is mainly designed to prevent acute pulmonary embolism. Few studies involve BCIS prevention by IVCF. The present study observed the preventive effects of IVCF against BCIS. The main results are as follows.1. BCIS model was successfully establishedFemur was truncated and bone cement was stuffed into the bone marrow cavity. Concomitantly, we monitored the pressure inside the bone marrow cavity and the degree of BCIS (blood pressure ,pulse oxygen saturation and fat embolism), which showed that the severity of BCIS is closely related to the pressure in femur cavity. When the pressure from 0 to 150 mmHg, the mean artery pressure (MAP) decreased from 95±4 mmHg to 80±6 mmHg (P<0.05), but there was not a significant change in pulse oxygen saturation (from (97±2) % to (92±4) %). With the pressure being reached to 300 mmHg, the MAP sharply fall to 60±11 mmHg (P<0.01 vs the MAP at 0 mmHg of femur cavity pressure) and oxygen saturation decreased to (85±5) % (P<0.01 vs the MAP at 0 mmHg intra-cavity pressure). By echocardiography, we measured the emboli in right atrium finding that the number and size of the emboli emerged when the intra-cavity pressure was 120 mmHg, became notable with the pressure of 150 mmHg and snow flask-like with 300 mmHg. sheep could simulate BCIS reliably under present conditions.2. IVCF was successfully implanted into inferior vena cava.IVCF was implanted and released into inferior vena cava of experimental sheep at the site 5 cm below kidney inferior pole monitored by 1250 mA fluoroscopic machine. Radiogragh and autopsy demonstrated the successful implantation of IVCF.3. Preventive effects of IVCF against BCISTen male sheep weighing 25-30 kg were randomly divided into 2 groups, IVCF (IVCF+BCIS) group and control (BCIS) group. For IVCF group, BCIS was established after IVCF implantation; for control group, vena cervicalis was cannulated but with no IVCF implantation. Ten ml bone cement (BC) was stuffed into bone marrow cavity, and intra-cavity pressure was gradually raised. Concomitantly, blood pressure (BP), heart rate (HR), central vena pressure and blood gas were monitored, and heart chamber changes were monitored by echocardiography. The lung was sliced and stained with oil red for fat embolis observation after surgery.1) The effects of IVCF on hemodynamic disorder induced by BCISIn the second series of experiments, we investigated the changes of artery and venous pressures with time. The data showed that artery systolic pressure dropped after bone cement implantation, from 132±9 mmHg 5 min after implantation to 132±9 mmHg 25 min after implantation. While pre-implantation of IVCF significantly postponed the decrease of artery systolic blood pressure (from 135±12 mmHg to 120±11 mmHg). The pulse pressure changed similarly with artery systolic pressure. On contrast, central venous pressure changed to another direction. Central venous pressure climbed up both in BCIS group and IVCF+BCIS group, with the change of the later is much more significant.2)Influences of IVCF on the changes of blood gas induced by BCIS.Our results showed that PaO2 decreased during bone cement implantation both in the BCIS and IVCF+BCIS groups. But the decrease of PaO2 dropped faster in the BCIS group, developing a respiratory failure 20 min after implantation in all the 4 sheep. Ten minutes after bone cement implantation, BCIS group manifested pH decreas, PaCO2 increase and HCO3 decrease, which suggested type 2 respiratory failure happened, with respiratory acidosis combined with metabolic acidosis. Furthermore, potassium in BCIS group was also increased in BCIS group, but not in IVCF+BCIS group.3) Preventive effects of IVCF on pulmonary embolism caused by bone cement implantation.As mentioned above, bone cement implantation caused uneven dotted echoes in right atrium of BCIS group when the intra-cavity pressure increased to 120 mmHg. The echoes were exaggerated to snow-flask-like with the increase of intra-cavity pressure. On contrast, such echoes were invisible even when the intra-cavity pressure increased to 300 mmHg and 400 mmHg. Oil red staining demonstrated that many fat emboli were present in lungs of BCIS group, but not in IVCF+BCIS group.In conclusion, IVCF is able to prevent BCIS during bone cement implantation.