Serum-neuroproteins, near-infrared spectroscopy, and cognitive outcome after beach-chair shoulder surgery: Observational cohort study analyses.

BACKGROUND: Cerebral hypoxia may occur during surgery but currently used cerebral oxygenation saturation (rSO2) monitors remain controversial with respect to improving clinical outcome. Novel neuroprotein biomarkers are potentially released into systemic circulation and combined with near-infrared spectroscopy (NIRS) could clarify the presence of per-operative cerebral hypoxia. We investigated changes to serum-neuroprotein concentrations post-surgically, paired with NIRS and cognitive outcome, in patients operated in the beach chair position (BCP). METHODS: A prospective cohort in 28 shoulder surgery patients placed in the BCP. Blood samples were collected before induction of anaesthesia, and 2 hours and 3-5 days post-operatively. We analysed blood levels of biomarkers including tau and neurofilament light (NFL). We post hoc assessed the cross-wise relationship between biomarker levels and post-surgical changes in cognitive function and intraoperatively monitored rSO2 from NIRS. RESULTS: Serum-NFL decreased from 24.2 pg/mL to 21.5 (P = .02) 2 hours post-operatively, then increased to 27.7 pg/mL on day 3-5 (P = .03). Conversely, s-tau increased from 0.77 pg/mL to 0.98 (2 h), then decreased to 0.81 on day 3-5 (P = .08). In 14/28 patients, episodic rSO2 below 55% occurred, and the duration < 55% was correlated to change in s-tau (P < .05). The cognitive function z-score at 1 week and 3 mo. correlated to the change in tau (P = .01), but not to NFL. CONCLUSION: Some biomarkers were significantly changed with surgery in the beach chair position. The change was at some points associated to post-operative cognitive decline, and to intraoperative low rSO2. (237).

The Analgesic Effect of Obturator Nerve Block Added to a Femoral Triangle Block After Total Knee Arthroplasty: A Randomized Controlled Trial.

BACKGROUND AND OBJECTIVES: Total knee arthroplasty (TKA) is associated with severe pain, and effective analgesia is essential for the quality of postoperative care and ambulation. The analgesic effects of adding an obturator nerve block (ONB) to a femoral triangle block (FTB) after TKA have not been tested previously. We hypothesized that combined ONB and FTB will reduce opioid consumption and pain compared with those of a single FTB or local infiltration analgesia (LIA). METHODS: Seventy-eight patients were randomized to combined ONB and FTB, single FTB, or LIA after primary unilateral TKA. The primary outcome was morphine consumption during the first 24 postoperative hours. Secondary outcomes included morphine consumption during the first 48 postoperative hours, pain at rest and passive knee flexion, nausea and vomiting, cumulated ambulation score, and Timed Up and Go test. RESULTS: Seventy-five patients were included in the analysis. The total intravenous morphine consumption during the first 24 postoperative hours was 2 mg (interquartile range [IQR], 0-15) in the combined ONB and FTB group, 20 mg (IQR, 10-26) in the FTB group (P = 0.0007), and 17 mg (IQR, 10-36) in the LIA group (P = 0.002). The combined ONB and FTB group displayed reduced pain, nausea, and vomiting compared with the other groups. The ambulation tests showed no statistically significant differences between the groups. CONCLUSIONS: Addition of ONB to FTB significantly reduced opioid consumption and pain after TKA compared with a single FTB or LIA, without impaired ambulation.

[Cerebral infarction can be a consequence of anaesthesia in beach chair position]. / Cerebral infarkt kan være en følge af anæstesi i beach chair-position.

Performing orthopaedic surgery in beach chair position (BCP) is a common procedure in Denmark. In this case report we present a patient, who underwent standard procedure with no variations according to the general anaesthesia. The arterial blood pressure after entering BCP and during surgery was acceptable. In the recovery phase the patient did not gain full consciousness, his blood pressure turned high and he developed seizures. A. cerebri media infarction was identified, and severe brain damage was the consequence. We question the rationale for using BCP as well as the use of phenylephrine for the cerebral hypoperfusion.