After craniotomy is performed by the neurosurgeon during frontal orbital advancement in a 6.8 kg 8 month old male with non-syndromic craniosynostosis, you notice that the arterial blood pressure quickly drops to 49/23 from 81/37 and EtCO2 decreases from 37 to 17. What are the most likely cause(s)?
a) sagittal sinus transection
b) transfusion of PRBCs 30 minutes ago
c) venous air embolism
d) a and c
e) all of the above
Answer d. Massive blood loss with hemorrhagic shock and significant venous air embolism are potential causes of severe hemodynamic instability during major craniofacial surgery. Sagittal sinus transection following craniotomy during exposure of the cranial vault during a frontal orbital advancement is a potential source of massive blood loss and should be anticipated. If a significant volume of air is entrained secondary to the relative wide surface area of the osteotomies in this infant, significant hypotension and decreased cardiac output are possible. Citrate toxicity is a potential source of significant hypotension and should be considered in the differential; however, it would be unlikely to rapidly present in the setting of prior blood transfusion as in this case.