Amplified Inflammatory Response to Sequential Hemorrhage, Resuscitation, and Pulmonary Fat Embolism An Animal Study
ABSTRACT The objective of this study was to assess the role of pulmonary fat embolism caused by intramedullary pressurization of the femoral canal in the development of acute lung injury in the setting of acute hemorrhagic shock and resuscitation.
Thirty New Zealand White rabbits were randomly assigned to one of four groups: (1) nine animals in which hemorrhagic shock was induced by carotid bleeding, resuscitation was performed, and the femoral canal was reamed and pressurized with bone cement to induce fat embolism (hemorrhagic shock and resuscitation/fat embolism [HR/FE] group); (2) six animals in which shock was induced by carotid bleeding, resuscitation was performed, and a sham knee incision was made and closed without drilling, reaming, or pressurization (hemorrhagic shock and resuscitation [HR] group); (3) eight animals in which no hemorrhage or shock was induced but the femoral canal was reamed and pressurized with bone cement to induce fat embolism (fat embolism [FE] group); and (4) seven animals that had a three-hour ventilation period followed by a sham knee incision (control group). The animals were ventilated for four hours following closure. Flow cytometry with use of antibodies against CD45 and CD11b was performed to test neutrophil activation in whole blood. Histological examination of lung specimens was also performed. Plasma and bronchoalveolar lavage fluid were analyzed for monocyte chemotactic peptide-1 and interleukin-8 levels with use of the ELISA (enzyme-linked immunosorbent assay) method.
Three animals in the HR/FE group died immediately after canal pressurization and were excluded. CD11b mean channel fluorescence was significantly elevated, as compared with baseline, only in the HR/FE group at two hours (p = 0.025) and four hours (p = 0.024) after knee closure. Histological analysis showed that only the HR/FE (p < 0.001) and HR (p = 0.010) groups had significantly greater infiltration of alveoli by polymorphonuclear leukocytes as compared with that in the controls. No significant differences in plasma cytokine levels were found between the groups. Only the HR/FE group had significantly higher interleukin-8 (p = 0.020) and monocyte chemotactic peptide-1 (p = 0.004) levels in the bronchoalveolar lavage fluid as compared with those in the controls.
Fat embolism from canal pressurization alone did not activate a pulmonary inflammatory response. The combination of hemorrhagic shock, resuscitation, and fat embolism elicited neutrophil activation, infiltration of alveoli by polymorphonuclear leukocytes, and inflammatory cytokine expression in bronchoalveolar lavage fluid.
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ABSTRACT: The aim of this study was to compare the effect of supine versus lateral position on clinical signs of fat embolism during orthopedic trauma surgery. Dogs served as the current study model, which could be extended and/or serve as a basis for future in vivo studies on humans. It was hypothesized that there would be an effect of position on clinical signs of fat embolism syndrome in a dog model. 12 dogs were assigned to supine (n = 6) and lateral (n = 6) position groups. Airway pressures, heart rate, blood pressure, cardiac output, pulmonary artery pressure, pulmonary artery wedge pressure, right atrial pressure, arterial and venous blood gases, white blood count, platelet count and neutrophil count were obtained. Dogs were then subjected to pulmonary contusion in three areas of one lung. Fat embolism was generated by reaming one femur and tibia, followed by pressurization of the canal. No difference was found in any parameters measured between supine and lateral positions at any time (0.126 < P < 0.856). The position of trauma patients undergoing reamed intramedullary nailing did not alter the presentation of the features of the lung secondary to fat embolism.Indian Journal of Orthopaedics 03/2014; 48(2):203-10. DOI:10.4103/0019-5413.128769 · 0.62 Impact Factor
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ABSTRACT: Numerous experimental studies have been performed to investigate the adverse effects of reamed versus unreamed nailing in isolated or combined trauma models. However, the translational relevance is still discussed controversially.Journal of Trauma and Acute Care Surgery 06/2014; 76(6):1495-506. DOI:10.1097/TA.0000000000000236 · 1.97 Impact Factor
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ABSTRACT: The aim of the present study was to develop an animal model of pulmonary fat embolism (PFE) caused by femoral intramedullary procedures, and to investigate the initial changes in the hemodynamics, cytokines and risk factors of PFE. Sixteen dogs were randomly divided into two groups: Group A (intramedullary reaming and bone cement injection, n=8) and Group B (surgical approach without opening the medullary cavity, n=8). The hemodynamics, arterial blood gases and relevant cytokines were evaluated, and the lungs were examined using Oil Red O staining. In the animals of Group A, the heart rate, central venous pressure, mean pulmonary arterial pressure, pulmonary capillary wedge pressure and extravascular lung water (EVLW) were increased compared with the baseline levels, while the mean arterial pressure was decreased immediately following the reaming and bone cement infusion (P<0.05). Furthermore, there was a significant reduction in the pH and the arterial oxygen tension (PaO2), and a significant increase in the arterial carbon dioxide tension (PaCO2; P<0.05 for all) following the bilateral intramedullary surgery. The EVLW was correlated with the PaO2 (P<0.001) and PaCO2 (P=0.046). Following surgery, there was a significant increase in tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 levels in Group A (P<0.05). However, there were no significant changes in these parameters in Group B. The parameters tested, with the exception of pH, were significantly different in Group A compared with those in Group B (P<0.05) following the bilateral intramedullary surgery. Oil Red O staining was positive for all animals in Group A and negative for those in Group B. Femoral intramedullary surgery may induce PFE and subsequently affect hemodynamics and arterial blood gases. EVLW was correlated with the PaO2 (P<0.001) and the PaCO2 (P=0.046). These results demonstrated that EVLW and cytokines may serve as predictors of the development of fat embolism syndrome (FES).Experimental and therapeutic medicine 08/2013; 6(2):469-474. DOI:10.3892/etm.2013.1143 · 0.94 Impact Factor