Patient state index and cerebral blood flow changes during shoulder arthroscopy in beach chair position

• Published in: Brazilian journal of anesthesiology (Elsevier) Vol. 66; no. 5; pp. 470 - 474
• Main Authors: Buget, Mehmet Ilke, Atalar, Ata Can, Edipoglu, Ipek Saadet, Sungur, Zerrin, Sivrikoz, Nukhet, Karadeniz, Meltem, Saka, Esra, Kucukay, Suleyman, Senturk, Mert N.
• Format: Journal Article
• Language: English
• Published: Brazil Elsevier Editora Ltda 01-09-2016; Sociedade Brasileira de Anestesiologia; Elsevier
• Subjects: Adult; ANESTHESIOLOGY; Arterial Pressure; Arthroscopy - methods; Beach chair position; Cerebral; Cerebral blood flow; Cerebral Cortex - blood supply; Cerebral Cortex - diagnostic imaging; Cerebrovascular Circulation; Conscious Sedation; Electroencephalography; Female; Fluxo sanguíneo cerebral; Heart Rate; Humans; Male; Middle Aged; Patient Positioning - methods; Patient state index; Pilot Projects; Posição de cadeira de praia; Prospective Studies; Shoulder - surgery; Ultrasonography, Doppler, Transcranial; Patient state index; Posição de cadeira de praia; Cerebral; Beach chair position; Fluxo sanguíneo cerebral; Cerebral blood flow; Patient State Index
• ISSN: 0104-0014; 1806-907X; 0104-0014
• DOI: 10.1016/j.bjane.2015.02.002

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.
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.
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.
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.
O objetivo do estudo foi demonstrar as possíveis alterações hemodinâmicas e do fluxo sanguíneo cerebral (FSC) em pacientes que foram posicionados de supinação para cadeira de praia (CP) e detectar se a mudança de posição causa alguma alteração na atividade cortical como mensurado pelo monitor de EEG com 4 canais.
No total, 35 pacientes foram incluídos. Antes da indução, os valores da PAM e do IEP foram registrados (T0). Após a intubação, ultrassonografias com Doppler da carótida interna e artérias vertebrais dos pacientes foram avaliadas para adquirir os valores do FSC a partir da fórmula. Em supinação, os valores da PAM, IEP e FSC foram registrados (T1) e o paciente foi posicionado em CP. Após 5 minutos, todas as mensurações foram repetidas (T2). As mensurações do IEP e PAM foram repetidas após 20 (T3) e 40 minutos (T4).
Houve uma diminuição significativa entre T0 e T1 na FC (80,5±11,6 vs. 75,9±14,4 bpm), PAM (105,8±21,9 vs. 78,9±18,4mmHg) e IEP (88,5±8,3 vs. 30,3±9,7) (p<0,05 para todos). A PAM diminuiu significativamente após a mudança de posição e permaneceu diminuída em relação a T1. A análise global dos valores do IEP (T1-T4) não mostrou nenhuma mudança significativa, mas a comparação de apenas T1 e T2 resultou em redução estatisticamente significativa do IEP. Houve redução significativa do FSC após o posicionado em CP.
O posicionado em CP foi associado à diminuição do FSC e dos valores do IEP. O IEP foi afetado pela mudança gravitacional do FSC; no entanto, ambos os fatores não estavam diretamente correlacionados entre si. Além disso, a diminuição do valor do IEP foi transitória e voltou aos valores normais dentro de 20 minutos.