Cerebral Oxygen Saturation Measured by Near-infrared Spectroscopy and Jugular Venous Bulb Oxygen Saturation during Arthroscopic Shoulder Surgery in Beach Chair Position under Sevoflurane-Nitrous Oxide or Propofol-Remifentanil Anesthesia

Abstract

Background:We examined the effects of different anesthetics on cerebral oxygenation and systemic hemodynamics in patients undergoing surgery in beach chair position (BCP). Jugular venous bulb oxygen saturation (SjvO 2 ) and regional cerebral tissue oxygen saturation (SctO 2 ) were determined while patients were placed from the supine to BCP. Whether SctO 2 and SjvO 2 are interchangeable in assessing the cerebral oxygenation was also examined. Methods: Forty patients undergoing shoulder surgery in BCP were randomly assigned to receive sevoflurane-nitrous oxide (S/N) or propofol-remifentanil (P/R) anesthesia. Four patients taking angiotensin II receptor antagonists were excluded post hoc. Mean arterial pressure and heart rate, as well as SjvO 2 and SctO 2 , were measured before (postinduction baseline in supine position) and after BCP. Results: Mean arterial pressure decreased by BCP in both groups. It was, however, significantly higher in S/N (n ϭ 19) than in P/R group (n ϭ 17) at 7 to 8 min after the positioning. SjvO 2 also significantly decreased after BCP in both groups, the magnitude of which was lower in S/N than in P/R group (11 Ϯ 10% vs. 23 Ϯ 9%, P ϭ 0.0006). The incidences of SjvO 2 Ͻ50% and mean arterial pressure less

Cerebral oxygenation in the beach chair position before and during general anesthesia in patients with and without cardiovascular risk factors

“…Collectively, it might be concluded that general anesthesia using sevoflurane in combination with some vasoactive agents including phenylephrine may modulate hemodynamic changes according to the beach chair position. Indeed, a recent study has documented that sevoflurane-nitrous oxide, but not propofol-remifentanil, anesthesia affords an advantage to stabilize the mean blood pressure in the beach chair position [3]. Irrespective of decreases in both blood pressure and heart rate, the beach chair position under general anesthesia did not alter the cerebral TOI values throughout the current study.…”

“…First, sevoflurane, compared with isoflurane, reportedly well preserves dynamic cerebral pressure autoregulation in humans [16]. Sevofluranenitrous oxide, but not propofol-remifentanil, anesthesia keeps up cerebral oxygen saturation measured by near-infrared spectroscopy as well as jugular venous bulb oxygen saturation in the beach chair position [3]. These results suggest that sevoflurane favors maintenance of cerebral oxygenation in the beach chair position.…”

“…However, a possible decrease in cerebral oxygenation related to this position has been suggested by many previous reports, although exact mechanisms of the catastrophic complication remain to be determined [2][3][4].…”

Middle cerebral artery blood flow velocity during beach chair position for shoulder surgery under general anesthesia

“…At the present time, neither SctO 2 nor SvjO 2 has proven to be useful in this setting [9,17]. The threshold to identify cerebral ischemia with SctO 2 and SvjO 2 remains unknown and is influenced by the cerebral metabolic rate for O 2 to cerebral blood flow ratio, patient cerebrovascular disease, and technology-dependent variables.…”

In reply: Management of blood pressure alters cerebral oxygen saturation values in the beach chair position

“…3 The impact of extracranial contamination on cerebral oxygenation values indeed depends on the technology employed. However, changes in jugular venous bulb oxygenation 4 and middle cerebral artery blood velocity 5 were reported in patients in the upright position, suggesting a large intracranial contribution to the measured value.…”