title: [Patient state index and cerebral blood flow changes during shoulder arthroscopy in beach chair position].
abstract: OBJECTIVE
  The aim of the study were to demonstrate the possible hemodynamic changes and cerebral blood flow alterations in patients who were positioned from supine to beach chair position; and to detect if the position change causes any cortical activity alteration as measured by the 4-channeled electroencephalography monitor.
  
  
  METHODS
  35 patients were included. Before the induction, mean arterial pressure and patient state index values were recorded (T0). After the intubation, doppler-ultrasonography of the patients' internal carotid and vertebral arteries were evaluated to acquire cerebral blood flow values from the formula. In supine position, mean arterial pressure, patient state index and cerebral blood flow values were recorded (T1) and the patient was positioned to beach chair position. After 5min all measurements were repeated (T2). Measurements of patient state index and mean arterial pressure were repeated after 20 (T3), and 40 (T4)min.
  
  
  RESULTS
  There was a significant decrease between T0 and T1 in heart rate (80.5±11.6 vs. 75.9±14.4beats/min), MAP (105.8±21.9 vs. 78.9±18.4mmHg) and PSI (88.5±8.3 vs. 30.3±9.7) (all p<0.05). Mean arterial pressure decreased significantly after position change, and remained decreased, compared to T1. The overall analysis of patient state index values (T1-T4) showed no significant change; however, comparing only T1 and T2 resulted in a statically significant decrease in patient state index. There was a significant decrease in cerebral blood flow after beach chair position.
  
  
  CONCLUSIONS
  Beach chair position was associated with a decrease in cerebral blood flow and patient state index values. Patient state index was affected by the gravitational change of the cerebral blood flow; however, both factors were not directly correlated to each other. Moreover, the decrease in patient state index value was transient and returned to normal values within 20min.
authors.affiliation: İstanbul University, Istanbul Medical Faculty, Department of Anaesthesiology, İstanbul, Turquia. Electronic address: mbuget@yahoo.com.
authors.forename: Mehmet Ilke
authors.initials: MI
authors.lastname: Buget
authors.affiliation: İstanbul University, Istanbul Medical Faculty, Department of Orthopedics and Traumatology, İstanbul, Turquia.
authors.forename: Ata Can
authors.initials: AC
authors.lastname: Atalar
authors.affiliation: İstanbul University, Istanbul Medical Faculty, Department of Anaesthesiology, İstanbul, Turquia.
authors.forename: Ipek Saadet
authors.initials: IS
authors.lastname: Edipoglu
authors.affiliation: İstanbul University, Istanbul Medical Faculty, Department of Anaesthesiology, İstanbul, Turquia.
authors.forename: Zerrin
authors.initials: Z
authors.lastname: Sungur
authors.affiliation: İstanbul University, Istanbul Medical Faculty, Department of Anaesthesiology, İstanbul, Turquia.
authors.forename: Nukhet
authors.initials: N
authors.lastname: Sivrikoz
authors.affiliation: İstanbul University, Istanbul Medical Faculty, Department of Anaesthesiology, İstanbul, Turquia.
authors.forename: Meltem
authors.initials: M
authors.lastname: Karadeniz
authors.affiliation: İstanbul University, Istanbul Medical Faculty, Department of Anaesthesiology, İstanbul, Turquia.
authors.forename: Esra
authors.initials: E
authors.lastname: Saka
authors.affiliation: İstanbul University, Istanbul Medical Faculty, Department of Anaesthesiology, İstanbul, Turquia.
authors.forename: Suleyman
authors.initials: S
authors.lastname: Kucukay
authors.affiliation: İstanbul University, Istanbul Medical Faculty, Department of Anaesthesiology, İstanbul, Turquia.
authors.forename: Mert N
authors.initials: MN
authors.lastname: Senturk
keywords: Beach chair position; Cerebral; Cerebral blood flow; Fluxo sanguíneo cerebral; Patient State Index; Patient state index; Posição de cadeira de praia