Elsevier

Injury

Volume 43, Issue 5, May 2012, Pages 608-612
Injury

Systemic fat embolism and the patent foramen ovale—A prospective autopsy study

https://doi.org/10.1016/j.injury.2010.08.027Get rights and content

Abstract

A fat embolism is a known and common complication of blunt force injuries, especially pelvic and long bones fractures. The aim of this study was to determine the importance of a patent foramen ovale (PFO) in developing systemic fat embolism (SFE) and eventually fat embolism syndrome (FES) in patients suffering from orthopaedic blunt injuries and consequent lung fat embolism. The sample was divided: 32 subjects with a sealed foramen ovale (SFO), and 20 subjects with a PFO. In our sample, there was no difference in either the incidence of renal fat embolism in subjects with PFO compared to those with SFO (Fisher's exact test 0.228, p = 0.154) or in the grade of renal fat embolism (Pearson Chi-square 2.728, p = 0.435). However, there was a statistically significant correlation between the grade of lung fat embolism and the number of fractured bones for the whole sample (Spearman's rho 0.271, p = 0.052), but no correlation between the grade of lung fat embolism and the ISS or NISS (Pearson correlation 0.048, p = 0.736, and 0.108, p = 0.445, respectively). In our study, the presence of fat emboli in the kidney, i.e. SFE, could effectively be predicted by the grade of lung fat embolism (the moderate and slight grades of lung fat embolism were better predictors than the massive one: logistic regression – Wald. Coeff. = 11.446, p = 0.003, Wald. Coeff. = 10.553, p = 0.001, and Wald. Coeff. = 4.128, p = 0.042), and less effectively by presence of PFO (Wald. Coeff. = 2.850, p = 0.091). This study pointed out that lung and SFE are not pure biomechanical events, so the role of a PFO is not crucial in developing a lung fat embolism into a systemic embolism: the fat embolism is more of a biochemical and pathophsyiological event, than a biomechanical one. The appearance of a patent foramen ovale associated with a systemic fat embolism should be less emphasised: maybe arteriovenous shunts and anastomosis between the functional and nutritive, i.e. systemic circulation of lungs play a more important role in developing a SFE than a PFO.

Introduction

A fat embolism refers to the presence of fat globules in the lung parenchyma and peripheral circulation.7 It is a known and common complication of blunt force injuries, especially pelvic and long bones fractures. The occurrence of a post-traumatic fat embolism in autopsy reports in these trauma patients is up to 96–100%.5, 15, 30 A post-traumatic lung fat embolism is usually a subclinical event: fat globules from site of fracture are intravasated into the venous system and are sequestered in the lungs.26 From the lungs, fat globules can enter the systemic circulation and reach all body organs. The systemic fat embolism (SFE) associated with progressive respiratory distress and a deteriorating central nervous system function is fat embolism syndrome (FES).7 Clinically, only 1–10% of patients develop FES, with a mortality rate of 5–10%.6, 11 The clinical picture is very variable and is often missed, and all too often the diagnosis is made post-mortem.16 It is not fully understood why some individuals are susceptible to FES whilst others are not.26

The presence of fat emboli in pulmonary and systemic blood vessels in the autopsy does not necessarily mirror a clinical manifestation of FES. The true incidence of FES is probably notably higher than reported and is merely masked by the associated injuries in more severely injured persons. It can be assumed that FES is most likely to be associated with a massive fat intravasation or alternatively with an abnormal patient reaction to the fat intravasation.18

Some authors suggest that the presence of a patent foramen ovale is a risk factor for developing more severe manifestations of FES.1, 33 There are reports of a reduction in systemic fat emboli during orthopaedic surgery after foramen ovale closure.13 Other authors consider that it is reasonable to believe that SFE and FES associated with a patent foramen ovale should be less emphasised.19

The aim of this study was to determine the importance of a patent foramen ovale in developing SFE and eventually FES in patients suffering from orthopaedic blunt injuries and consequent lung fat embolism.

Section snippets

Methods

A prospective autopsy study was performed. Subjects who suffered blunt force injuries were included in the study, especially orthopaedic trauma: each deceased had a fracture of the pelvic and/or long bones of the lower limbs – femur and/or tibia. All the injured died in the hospital, no less than 18 h and no more than 2 weeks after admission. Only subjects older than 18 years were included in the study: the incidence of FES in children is said to be up to 100 times lower than in adults.38

During

Results

The sample included 52 subjects that fulfilled the listed criteria. Most of the deceased died due to head injuries – 17 of them. Chest and abdominal injuries were a less common cause of death – 4 and 3 subjects, respectively. Prolonged hemorrhagic shock was the cause of death in 8 persons. Complications due to the injuries were the cause of death in 20 of the subjects observed.

The sample was divided into two subgroups: with a sealed foramen ovale (SFO) – 32 subjects, and with a patent foramen

Discussion

After blunt force injury and the fracture of the pelvic and long bones, fat globules from the bone medullary channel reach the right part of the heart and lungs through ruptures of veins within the injury zone. Veins within the marrow cavity are held apart by their osseous attachments, allowing fat to enter with relative ease.18 In our sample, all the subjects suffered from post-traumatic lung fat embolism as a consequence of the pelvic bone and/or long bone fractures.

If the quantity of fat

Conclusions

Our survey is the first prospective autopsy study dealing with the role of a patent foramen ovale in the appearance of systemic fat embolism, in patients with pelvic and/or long bone fractures, i.e. sustained blunt force trauma. This study pointed out that lung and systemic fat embolism are not pure biomechanical events, so the role of a patent foramen ovale is not crucial in developing a lung fat embolism into a systemic embolism: the fat embolism is more of a biochemical and

Conflict of interest statement

The authors declare that there are no conflicts of interest.

Acknowledgements

Study was supported by Ministry of Science and Technological Development of Republic of Serbia as a part of the project “Age related microarchitectural and mechanical bone properties: Implications for increased fragility” Gr. No. 45005.

References (38)

  • R. Byrick

    Fat embolism: a central nervous system problem

    Semin Cardiothorac Vasc Anesth

    (2002)
  • R.J. Byrick et al.

    Transpulmonary systemic fat embolism. Studies in mongrel dogs after cemented arthroplasty

    Am J Respir Crit Care Med

    (1994)
  • L. Cabanes et al.

    Atrial septal aneurysm and patent foramen ovale as risk factors for cryptogenic stroke in patients less than 55 years of age: a study using transesophageal echocardiography

    Stroke

    (1993)
  • Collard M. Fettembolie. Baden-Baden Bruessel: Verlag Gerhard Witzstrock GmbH;...
  • T.C. Fabian et al.

    Fat embolism syndrome: prospective evaluation in 92 fracture patients

    Crit Care Med

    (1990)
  • G. Falzi et al.

    On pulmonary fat embolism after injuries with different periods of survival

    Munch Med Wochenschr

    (1964)
  • A.M. Forteza et al.

    Endovascular closure of a patent foramen ovale in the fat embolism syndrome: changes in the embolic patterns as detected by transcranial Doppler

    Arch Neurol

    (2002)
  • T. Fracasso et al.

    Immunohistochemical identification of revalent right ventricular ischemia causing right heart failure in cases of pulmonary fat embolism

    Int J Legal Med

    (2009)
  • T.A. Gitin et al.

    Pulmonary microvascular fat: the significance?

    Crit Care Med

    (1993)
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