Adverse effects on the brain in connection with isoflurane‐induced hypotensive anaesthesia

Abstract

As a marker of brain cell injury, adenylate kinase (AK) was measured in cerebrospinal fluid (CSF) in 10 patients given anaesthesia with isoflurane-induced hypotension for corrective surgery of dentofacial deformities. Nine out of 10 patients displayed a marked increase in CSF-AK postoperatively compared with preoperative values. The postoperative mean value displayed a 400% increase compared to the corresponding preoperative value. This difference was statistically significant (P = 0.001). The rise in CSF-AK was most probably the result of an enhanced efflux of AK into CSF subsequent to a presumed hypoxic injury to brain cells.

Occurrence of Adenylate Kinase in Cerebrospinal Fluid after Isoflurane Anaesthesia and Orthognathic Surgery

“…Confirmatory of a previous study the present work indicated an adverse metabolic effect on the brain in connection with isoflme-induced hypotension and orthognathic surgery (9). This was indicated by the release of a biochemical marker most probably originating from brain cells into the CSF in 24 of 37 patients (65%), and also indicated by a deterioration in psychometric tests in 4 patients out of 17 (24%) analysed.…”

“…Thus, under normal conditions the CSF-activity of this enzyme is zero or very low, <0.040 U/L (28). The previously observed enhanced efflux of AK into CSF in association with isoflurane-induced hypotensive anaesthesia was considered to be due to hypoxic brain cell injury secondary to hypotension (9). However, conflicting reports have been presented concerning the adverse effects of induced hypotensive anaesthesia on the brain (7,13,22,29).…”

“…A study population of 36-40 patients was deemed necessary by calculating data from a previous pilot study, and making the assumption of a mean group difference in CSF-AK of at least 0.040 U/L at the 5% significance level and with a statistical power of minimum 80% (9). An unpaired, two-sided t-test was used.…”

“…An increase in the activity of adenylate kinase (AK) in cerebrospinal fluid (CSF) has been demonstrated in connection with isoflurane-induced hypotensive anaesthesia in 9 out of 10 patients investigated pre-and postoperatively (9). Increased CSF-AK activity has been associated with disturbances of brain cell integrity under different pathophysiological conditions, including meningitis, dementia, brain tumour necrosis, stroke, resuscitation, asphyxia in newborns and open heart surgery (8,10,24,25,28,30,32,33).…”

Effect of age on brain oxygenation regulation during changes in position

“…In this setting, modest hypotension or hypocapnia can accentuate brain hypoxic changes (Enlund et al, 1989;Hampson et al, 1990;Torella and McCollum, 2004). However, pathophysiological factors that may magnify this effect are unclear (Artru et al, 1998;Mehagnoul-Schipper et al, 2003).…”