Sildenafil prevents cardiovascular changes after bone marrow fat embolization in sheep.
BACKGROUND
Sudden, intraoperative cardiovascular deterioration as a result of pulmonary embolization of bone marrow fat is a potentially fatal complication during total hip and knee arthroplasty, intramedullary nailing, and spine surgery. Anesthetic management is challenging in the presence of increased right ventricular afterload due to pulmonary hypertension. Selective pulmonary vasodilation may be an appropriate prophylactic or therapeutic measure. The effect of sildenafil (phosphodiesterase inhibitor) on cardiovascular deterioration after bone marrow fat embolization was therefore investigated.


METHODS
Bone cement (polymethylmethacrylate) was injected into three lumbar vertebrae in 12 sheep. Invasive blood pressures and heart rate were recorded continuously until 60 min after the last injection. Cardiac output and arterial and mixed venous blood gas variables were measured at selected time points. Before the first cement injection, 6 animals received a bolus injection (0.7 mg/kg) of sildenafil, with continuous infusion (0.2 mg . kg . h) thereafter. Postmortem lung and kidney biopsies were taken for semiquantitative analysis of intravascular fat.


RESULTS
Fat embolism was associated with a transient increase (21 +/- 7mmHg) in pulmonary arterial pressure. A transient decrease in arterial blood pressure and temporary increases in central venous pressure and dead space were also observed. No significant changes in any cardiovascular variable were observed after fat embolism in the sildenafil group. There was significantly (P < 0.05) less intravascular fat in the lungs of the sildenafil (median count of 5 emboli per microscopic view) compared with the control group (median count of 1).


CONCLUSIONS
Administration of sildenafil prevented the acute cardiovascular complications after bone marrow fat embolism in sheep.
Krebs
Jörg
J
MEM Research Center, Institute for Surgical Technology and Biomechanics, Medical Faculty, University of Bern, Bern, Switzerland. jorg.krebs@MEMcenter.unibe.ch
Ferguson
Stephen J
SJ
Nuss
Katja
K
Leskosek
Boris
B
Hoerstrup
Simon P
SP
Goss
Ben G
BG
Aebli
Nikolaus
N
D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects; D001843:Bone Cements / Q000633:toxicity*; D001853:Bone Marrow / Q000473:pathology*; D002302:Cardiac Output / Q000187:drug effects; D004620:Embolism, Fat / Q000150:complications* / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000517:prevention & control*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000627:therapeutic use*; D019904:Polymethyl Methacrylate / Q000633:toxicity*; D011652:Pulmonary Circulation / Q000187:drug effects; D011687:Purines / Q000627:therapeutic use; D012756:Sheep; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*; D014655:Vascular Resistance / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
D001843:Bone Cements; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014665:Vasodilator Agents; D019904:Polymethyl Methacrylate; D000068677:Sildenafil Citrate