Severe pelvic fracture-related bleeding in pediatric patients: does it occur?

PURPOSE: Pediatric pelvic fractures are rare and less likely to cause hemodynamic instability than similar injuries in adult patients. The associated injuries are common, and they have a major impact on mortality. The aim of the present study was to evaluate the risk of life-threatening hemorrhage associated with unstable pelvic fractures in children. METHODS: We identified retrospectively all pediatric pelvic fractures (ring and acetabulum) treated at Helsinki University Central Hospital during a 10-year period (1998-2007). Stable A-type fractures (fractures not involving the pelvic ring) were excluded. All available pre- and in-hospital medical records were reviewed. The collected data consisted of patient characteristics, mechanisms of injury, vital signs, laboratory tests, care given, other injuries diagnosed, and the 30-day survival rate. RESULTS: There were 71 (40 males) pediatric patients (median age 14, range 1-16 years) with unstable pelvic fractures; 66 pelvic ring and 5 acetabulum fractures. The most common mechanism of injury was traffic accident (69%). Four patients had life-threatening bleeding. All had fracture of a mature pelvic ring, but the source of massive bleeding was pelvic ring fracture in only two patients (2.8% of all patients). No acetabulum fracture-related major pelvic bleeding was observed. One patient (age 16 years) required emergency surgery and angioembolization for pelvic bleeding. No life-threatening pelvic bleeding was seen among patients with immature bony pelvis. Pelvic ring fractures were surgically treated in 25 patients. Two patients died from head injuries (overall mortality 2.8%), but there were no bleeding-related deaths. CONCLUSIONS: We conclude that life-threatening bleeding from pelvic or acetabular fractures in pediatric patients is rare (2.8%), and does not contribute to the overall mortality.

Adaptive optical array receivers for detection of surface acoustic waves.

Adaptive interferometric detection systems based on two-wave mixing in photorefractive crystals have been configured as distributed optical receivers. The spatial distribution of the detection laser power on the sample surface is controlled by use of phase gratings and amplitude masks. The responses of point, line, array, and chirped optical receivers to propagating surface acoustic waves (SAW's) are discussed theoretically and demonstrated experimentally. It is shown that by use of different object beam footprints it is possible to configure adaptive holographic SAW receivers that are either broadband or narrow band and that are preferentially sensitive to SAW's propagating in given directions. The receivers also allow for the distribution of laser power over the sample, eliminating the excessive heating or surface damage that can occur in some materials when high power, point-focused, detection lasers are used.

Holographic recording of complex images by double phase conjugation in Bi(12)TiO(20) fiberlike crystal.

Volume holographic recording of complex images with a double phase-conjugation mirror in a fiberlike Bi(12)TiO(20) single crystal, mutually pumped by two separate He-Ne lasers, is experimentally demonstrated. Complex images can be stored and reconstructed by use of even a partial input image. The advantages of the small-cross-section, light-confining photorefractive sample in comparison with bulk crystal are a wider spatial bandwidth of recorded images and the possibility of recording holograms by application of smaller ac voltages.