Akademik Veri Yönetim Sistemi
Turk Anesteziyoloji ve Reanimasyon Dernegi Dergisi, cilt.31, sa.7, ss.341-346, 2003 (Scopus)
We aimed to investigate the effects of hyperventilation on cerebral blood flow (CBF) in order to maintain normocapnia following the deflation of the tourniquet in patients undergoing elective lower extremity operation during intravenous general anesthesia (TIVA). In all cases(n=15), anaesthesia was induced by 2 mg kg-1 propofol, 1 μg kg-1 remifentanyl and 1 mg kg-1 vecuronium, and was maintained with the mixture of 50 % air-O2, 6-8 mg kg-1 dk-1 propofol and 0.5 μg kg-1 dk-1 remifentanyl infusions. Patients were randomized into two groups. Group I (n=7) was ventilated by f=10/min and V T=8 mL kg-1. Patients in group II (n=8) were ventilated similarly as group I until the deflation of tourniquet, and following deflation by increasing respiratory frequency adjusted to maintain end-tidal CO 2 (PETCO2) between 30-35 mmHg. Middle cerebral artery (MCA) flow velocity was measured by transcranial Doppler ultrasonography as mean (m-MCA) and peak (p-MCA) values. Data were recorded 5 minutes before tourniquet deflation (control), and every minute in the first 10 minutes following deflation While there has been no difference for p-MCA, m-MCA and PaCO2 in group II, significant increases (p<0.05) in mean MCA flow velocity were obtained in 2nd, 3rd and 4th minutes in group I. Maximum increase was obtained in 3rd minute and determined as 52±7 cm/sec. The increases of PaCO2 were obtained in 2 to 6 minutes (p<0.05) and maximum level was 41±1 mmHg (25 %±3 %) in 3rd minute. We concluded that, the increase of MCA flow velocity and CBF related to the increase of PaCO2 after deflation of the pneumatic tourniquet may be prevented by maintaining normocapnia provided by increasing minute ventilation.