The main goals of neuroanesthesia are to maintain adequate cerebral perfusion pressure (CPP) and, consequently, cerebral blood flow (CBF) to guarantee sufficient oxygenation of the brain and to provide good surgical conditions for the neurosurgeon. This thesis aimed to examine critical aspects of neuroanesthesia with regard to CBF, CPP, blood coagulation, and transfusion of blood products. In our material the requirement of intraoperative blood product transfusion was low during surgery for ruptured arterial aneurysm. Intraoperative red blood cell transfusion (RBCT) seems to be preemptive in nature according to the hemoglobin levels prior to transfusion. RBCT is associated with intraoperative rupture of an aneurysm. Intraoperative RBCT may itself worsen SAH patients neurological outcome. In the event of sudden intraoperative rupture of an aneurysm, adenosine-induced asystole can be used to stop the bleeding and facilitate clipping of the aneurysm. Early infusion of fresh frozen plasma instead of crystalloids should be considered to compensate for expected excess bleeding in neurosurgery to preserve normal coagulation capacity. The potentially less harmful effect of hypertonic saline (HS), relative to mannitol, on blood coagulation may shift the decision towards HS when choosing an optimal solution for treatment of elevated ICP or brain swelling, at least when excess bleeding occurs. However, the clinical relevance of this finding remains unclear and warrants further study. Reliability of end-tidal concentration of carbon dioxide (EtCO2) as an estimate of arterial carbon dioxide partial pressure (PaCO2) after anesthesia induction is not adequate, as seen in the correlation between a decrease in mean arterial pressure and EtCO2-PaCO2 difference in our study. Optimal ventilation after induction of anesthesia should be confirmed by arterial blood gas analysis in patients undergoing neurosurgery to prevent a potentially harmful increase in PaCO2, and consequently, in CBF. Anesthesia in both sitting and prone positions is associated with changes in blood pressure and cardiac function. However, preemptive goal-directed therapy with either Ringer s acetate or hydroxyethyl starch (HES) solutions before positioning enables a stable hemodynamic state during neurosurgery in both positions. The fluid requirement did not differ between the two positions. Slightly less HES is needed to achieve comparable hemodynamics, but is it questionable whether this advantage outweighs the recent concerns regarding colloid safety.
|Status||Publicerad - 2015|
|MoE-publikationstyp||G5 Doktorsavhandling (artikel)|
- 3126 Kirurgi, anestesiologi, intensivvård, radiologi