The EC90 of remifentanil for blunting cardiovascular responses to head fixation for neurosurgery under total intravenous anesthesia with propofol and remifentanil based on bispectral index monitoring: estimation with the biased coin up-and-down sequential method

Abstract

BackgroundHead fixation can induce hemodynamic instability. Remifentanil is commonly used with propofol for total intravenous anesthesia (TIVA) during neurosurgery. This study investigated the 90% effective concentration (EC90) of remifentanil for blunting of cardiovascular responses to head fixation during neurosurgery via bispectral index (BIS) monitoring.MethodsFifty patients undergoing neurosurgery requiring head fixation were enrolled. This study was performed using the biased coin up-and-down design sequential method (BCD). After tracheal intubation, the effect-site target concentration (Ce) of remifentanil was adjusted to achieve hemodynamic stability and reset to the level preoperatively assigned to each patient, according to the BCD method, approximately 10 min before head fixation. Baseline hemodynamic values were recorded before head fixation. An ineffective response was defined as a case with a > 20% increase in hemodynamic values from baseline. Otherwise, the response was determined to be effective. The EC90 of remifentanil was calculated as a modified isotonic estimator.ResultsForty-three patients completed this study. The EC90 of remifentanil for blunting cardiovascular responses to head fixation was estimated to be 6.48 ng/mL (95% CI, 5.94–6.83 ng/mL).ConclusionsAdjustment of the Ce of remifentanil to approximately 6.5 ng/mL before head fixation could prevent noxious cardiovascular responses in 90% of neurosurgical ASA I-II patients aged 20 to 65 years old during propofol target-controlled infusion titrated to maintain BIS between 40 and 50.Trial registrationClinicalTrials.gov Identifier NCT01489137, retrospectively registered 5 December 2011.

Optimal Dexmedetomidine Dose to Prevent Emergence Agitation Under Sevoflurane and Remifentanil Anesthesia During Pediatric Tonsillectomy and Adenoidectomy

“…Dixon’s UDM was designed to estimate the median threshold, including the ED50 or EC50 (Dixon, 1991; Oron, 2006; Pace and Stylianou, 2007), it has many advantages such as small sample size, simple operation, and relatively accurate results. And it can estimate the ED90/EC90 or ED95/EC95 by extrapolation in a UDM study (Lee et al, 2017). Kim’s group reported that a dexmedetomidine bolus (0.38 μg/kg) could prevent 95% of 2- to 12-year-old pediatric EA cases after tonsillectomy and adenoidectomy with desflurane anesthesia (Kim et al, 2015).…”

Predicting the optimal concentration of remifentanil for skull pin fixation with hemodynamic and analgesia nociception index monitoring

“…Anesthesiologists may encounter hemodynamic changes that require pharmacological intervention due to a noxious stimulus resulting from skull pin fixation. Acute arterial hypertension may lead to intracranial hemorrhage and induce intracranial hypertension and cerebral edema in patients with intracranial tumor 2 , 3 . Thus, various strategies such as local anaesthetics, opioids, and scalp blocks have been used to blunt hemodynamic responses induced by skull pin fixation 2 , 4 – 7 .…”

“…Acute arterial hypertension may lead to intracranial hemorrhage and induce intracranial hypertension and cerebral edema in patients with intracranial tumor 2 , 3 . Thus, various strategies such as local anaesthetics, opioids, and scalp blocks have been used to blunt hemodynamic responses induced by skull pin fixation 2 , 4 – 7 . Though scalp block or local infiltration may provide adequate analgesia and hemodynamic stability, it requires extra time and is not our routine practice 2 .…”

“…Thus, various strategies such as local anaesthetics, opioids, and scalp blocks have been used to blunt hemodynamic responses induced by skull pin fixation 2 , 4 – 7 . Though scalp block or local infiltration may provide adequate analgesia and hemodynamic stability, it requires extra time and is not our routine practice 2 . Total intravenous anesthesia (TIVA) is a standard and widely used method of GA, especially for evoked potential monitoring during intracranial surgery 2 .…”

“…Though scalp block or local infiltration may provide adequate analgesia and hemodynamic stability, it requires extra time and is not our routine practice 2 . Total intravenous anesthesia (TIVA) is a standard and widely used method of GA, especially for evoked potential monitoring during intracranial surgery 2 . Due to its pharmacodynamic and pharmacokinetic characteristics, such as a very short context-sensitive half-time and minimal effects on cardiovascular system, remifentanil is a commonly used opioid in conjunction with propofol for TIVA 2 , 8 .…”