TITLE:
The Cardiac Function in the Beach Chair Position under General Anesthesia
AUTHORS:
Kumiko Tanabe, Yuko Yamada, Kiyoshi Nagase, Nobuo Terabayashi, Hiroki Iida
KEYWORDS:
Beach Chair Position, Cardiac Function, Cerebral Perfusion
JOURNAL NAME:
Open Journal of Anesthesiology,
Vol.8 No.1,
January
29,
2018
ABSTRACT:
Background: Shoulder surgery is performed in the beach chair position
(BCP). The systemic arterial blood pressure (BP) must be increased to prevent
cerebral hypoperfusion. However, it is not clear how the cardiac function is
affected when BP increase to maintain cerebral perfusion pressure in anesthetized
patients. Methods: An analysis was performed using the data from 13
patients. We prepared a parallel circuit using a FloTrac Sensor transducer and
an arterial BP transducer. Following the transfer of the patient to the BCP
under general anesthesia, the FloTrac Sensor transducer was placed at the level
of the fourth intercostal space, the arterial BP transducer was placed at the
external auditory meatus level. We selected two points before surgery (120 s
apart), during which the mean arterial BP (mABP) at the level of the brain
was stable and at which the values in the supine position and the BCP were
within 5 mmHg. Results: While the patients were in the supine position, the
mean mABP at the mid-axillary level was 65.7 mmHg. In the BCP, the mean
mABP was 66.5 mmHg at the external auditory meatus and 80.7 mmHg at the
fourth intercostal space. The cardiac index changed from 2.2 (supine position)
to 2.5 l/min/m2 (BCP). The stroke volume index was significantly increased
from 35.8 to 42.3 ml/m2 (P = 0.003). The heart rate changed from 63.0 to 58.6
beats/min. The stroke volume variation was significantly decreased from
12.4% to 8.8% (P = 0.024). Conclusion: In order to ensure patient safety,
close attention should be paid to the systemic cardiovascular changes that occur
when the BP is increased.