Premium
Epileptiform EEG during sevoflurane mask induction: Effect of delaying the onset of hyperventilation
Author(s) -
Vakkuri A.,
Jäntti V.,
Särkelä M.,
Lindgren L.,
Korttila K.,
YliHankala A.
Publication year - 2000
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1034/j.1399-6576.2000.440609.x
Subject(s) - hyperventilation , anesthesia , medicine , unconsciousness , heart rate , electroencephalography , sevoflurane , mean arterial pressure , blood pressure , psychiatry
Background: Hyperventilation during sevoflurane‐N 2 O‐O 2 mask induction in adults is associated with a hyperdynamic circulatory response and epileptiform electroencephalogram (EEG). We tested the hypothesis that delaying onset of hyperventilation will prevent severe (periodic) epileptiform EEG and hyperdynamic response. Methods: Thirty patients were randomized to receive either delayed (group D, n=15) or immediate (group I, n=15) onset of hyperventilation during sevoflurane (8% in N 2 O 50%) mask inhalation induction with single‐breath method for unconsciousness. Fifteen patients were allowed to breathe spontaneously for 2 min after loss of consciousness and controlled hyperventilation (ETCO 2 <4%) was started thereafter. In 15 patients controlled hyperventilation was started immediately after loss of consciousness. EEG was recorded, and mean arterial pressure (MAP) and heart rate (HR) registered. Results: Epileptiform EEG patterns were seen in 13 patients in group I and in 9 patients in group D (n.s.). Periodic epileptiform discharges (PED) tended to occur more often in group I ( P =0.07). Heart rate and MAP were higher in group I than in group D from 2 min to 3 min ( P <0.05), and both HR and MAP rose significantly from the baseline in group I. In group D, HR but not MAP rose significantly from baseline. Conclusion: Regardless of its timing, hyperventilation at a high sevoflurane concentration produced severe epileptiform EEG with a hyperdynamic response. PED tended to occur more often with immediate onset of hyperventilation ( Note ).