Amorim, Pedro

Correia, Rui P.

Leitão, A.

Nunes, Catarina S.

Rego, J.

Soares, Maria

Vide, Sérgio

English

Repositório Aberto da Universidade Aberta

synapsis of the reflexes across the central nervous system. Opioids affect pupilsize, but do seem not alter light reflex amplitude or constriction velocity andpropofol decrease both the amplitude of the light reflex independently of anychange in pupil size.2In this study, we wanted to assess the possibility of using differentcharacteristics of the PLR to predict loss of consciousness.Methods: This is an observational prospective study, where 25 consec-utive patients were enrolled. Patients scheduled for neurosurgical proce-dures, with general total intravenous anesthesia with propofol andremifentanil were considered when no premedication was used. The PLRwas measured using a portable infrared pupillometer (AlgiScan—IDMed, France) before and after loss of consciousness was achieved. Thepupillometer applied a flash of visible light and measured the minimumdiameter obtained afterwards, the response latency and velocity of con-traction. A logistic regression for loss of consciousness was then calcu-lating using these 3 variables. Data are presented as mean±SD.Results: The logistic regression model showed goodness of fit (Hosmerand Lemeshow test P= 0.921). Velocity of contraction was statisticalsignificant (P< 0.001, Exp(B) 0.98).Receiver operating characteristic curve of the predicted probabilitiesyielded an area under the curve of 0.982 (P< 0.001) (Fig. 1).Discussion: From this preliminary results, it seems that some measurementsrelated to the PLR can be used to detect loss of consciousness. However,further studies are needed to assess if it correlates with the time it ensues.References:1. Bosch L, Fernández-Candila J, León A, et al. Revista Española deAnestesiología y Reanimación. 2017;64:157–167.2. Couret D, Boumaza D, Grisotto C, et al. Crit Car 2016;20:99.[SNACC-105] Pupillary Pain Index correlates with PostoperativePain Scores in Neurosurgical PatientsVide S*, Correia R†, Rego J‡, Soares M†, Nunes C§, Leitão A∥, AmorimP†. *Hospital Pedro Hispano, Matosinhos. †Centro Hospitalar Do Porto.§Universidade Aberta. ∥Faculdade De Engenharia Do Porto, Porto.‡Centro Hospitalar Tamega E Sousa, Penafiel, Portugal.Background: Acute postoperative pain, if inadequately treated, not onlylimits mobility and impairs ventilation, but also increases stress hormonesand the risk for chronic postsurgical pain.1 In contrast, if opioids aregiven in excess they can cause respiratory depression, nausea and vom-iting, ileus, sedation and even hyperalgesia.1Adequate titration of analgesia intraoperatively lacks a widely acceptedmonitor. Nevertheless, some studies have addressed this issue by usingsurrogate variables of the autonomic nervous system to guide opioidadministration.2–3 In this study, we recorded the pupillary dilation re-sponse immediately before extubation and compared it with the ratings ofpatient’s pain reported in the postanesthesia care unit (PACU) using avisual analog scale (VAS).4Methods: Pupillary dilation response was determined through pupillom-etry using AlgiScan and its Pupillary Pain Index (PPI). The PPI consistsin measuring the changes in pupillary dilation in response to a con-tinuously increasing electric stimulus discharge, which then assigns scoresfrom 1 (when pupillary dilation is <5% despite maximal tetanic stim-ulation intensity) to 10 (when pupillary dilation rises above 13% with the10mA).3 Twenty-two patients undergoing neurosurgery were included inthis study. General anesthesia was induced and maintained with propofoland remifentanil, titrated to achieve adequate levels of sedation andanalgesia during the medical procedure. PPI measurements were per-formed after propofol was stopped at the end of surgery and beforeextubation. VAS pain assessment was performed at PACU arrival.Correlation analysis between PPI and VAS was assessed using 2-tailedSpearmen test with significance for P< 0.01. Data are presented asmean±SD.Results: Demographics were: 57± 13 years, 68.3± 9.1 kg, 163±8 cm, 9%ASA I, 82% ASA II, 9% ASA III, 15 females and 7 males. Mean PPIbefore extubation was 6.2± 2.5 and VAS at PACU arrival was 5± 2.6.VAS was correlated with PPI (Spearmen R= 0.57, P= 0.006), and couldbe predicted (adjusted R2= 0.41) as VAS= 0.79×PPI+0.046.Conclusions and Discussion: We found a correlation between pre-extubation PPI and the VAS at PACU arrival. This data suggest that PPIcould be used to titrate analgesia in the end of the intraoperative period,targeting optimal analgesia in the immediate postoperative period.References:1. Larson MD, Sessler DI. Anesthesiology 2012;116(5):980–982.2. Boselli E, Bouvet L, Bégou G, et al. Br J Anaesth. 2014;112(4):715–721.Abstracts J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017556 | www.jnsa.com Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.3. Maurer CA, Walensi M, Käser SA, et al. World J Hepatol. 2016;8(24):1038–1046.4. Gould D, Kelly D, Goldstone L, et al. J Clin Nurs. 2001;10(5):697–706.[SNACC-106] Clinical Epidemiology of Adults With ModerateTraumatic Brain InjuryWatanitanon A, Lyons V, Lele A, Krishnamoorthy V, Chaikittisilpa N,Chandee T, Vavilala M. University of Washington, Seattle, WA.Background: Moderate traumatic brain injury (TBI) is common but un-like mild or severe TBI, little is known about patients with moderate TBI.The aim was to describe the clinical epidemiology of patients specificallywith moderate TBI.Methods: We examined National Trauma Data Bank (NTDB) data be-tween 2007 and 2014 of adults (age older than 18 y) with moderate TBI(TBI ICD 9 codes and admission Glasgow Coma Scale [GCS] 9 to 13).Demographics, mechanism of injury, hospital course, and facility charac-teristics were examined. Admission characteristics associated with dischargeoutcomes were analyzed using multivariable Poisson regression models.Findings: Of 114,066 patients, most were white (62%), male (69%),and had median admission GCS 12 (IQR, 10-13). The leading injurymechanisms were falls (43%) and motor vehicle-related (34%). Seventy-seven percent had isolated TBI. Concussion, which accounted for 25% ofmoderate TBI, was the most frequent TBI diagnosis. Fourteen percentreceived mechanical ventilation and 66% were admitted to intensive careunit. Over 30% were admitted to a nontrauma center and 50% receivedcare at a community hospital. Seven percent died and 32% had a pooroutcome, including those with GCS 13. Compared with patients 18 to44 years, patients 45 to 64 years were twice as likely (aRR, 1.97; 95% CI,1.92-2.02), and patients over 80 years were 5 times as likely (aRR, 4.66;95% CI, 4.55-4.76) to have a poor outcome. Patients with a poor dis-charge outcome were more likely to have had hypotension at admission(aRR, 1.10; 95% CI, 1.06-1.14), lower admission GCS (aRR, 1.37; 95%CI, 1.34-1.40), higher ISS (aRR, 2.97; 95% CI, 2.86-3.09), and poly-trauma (aRR, 1.05; 95% CI, 1.02-1.07), compared with those withoutpoor discharge outcomes.Interpretation: Many patients with moderate TBI deteriorate, requireneurocritical care, and experience poor outcomes, but do not receive careat a trauma center.[SNACC-107] Awake Craniotomy for Cerebral Abscess in aPatient With Unrepaired Cyanotic Congenital Heart DiseaseGoettel N, Hofer A, D’Antico C, Tobler D, Zumofen D, Steiner L.University Hospital Basel, Basel, Switzerland.We report the case of a 39-year-old male with complex cyanotic con-genital heart disease undergoing emergency craniotomy for a cerebralabscess. Maintenance of intraoperative hemodynamic stability andadequate tissue oxygenation during anesthesia may be challenging inpatients with cyanotic congenital heart disease. In this case, we decided toperform the surgery as an awake craniotomy after interdisciplinaryconsensus. We discuss general aspects of anesthetic management duringawake craniotomy and specific concerns in the perioperative care ofpatients with congenital heart disease.[SNACC-108] High Spinal Block in a Patient With a PreexistingVentriculo-Peritoneal Shunt for Normal Pressure HydrocephalusYoung D, Trudeau J, Tang R, Flexman A. University of BritishColumbia, Vancouver, BC, Canada.Spinal anesthesia has been used successfully in patients with ventriculo-peritoneal (VP) shunts and high spinal block has not been previouslyreported in the literature in this population. We describe a 74-year-oldpatient with normal pressure hydrocephalus (NPH) and a functioning VPshunt who presented for transurethral resection of a bladder tumor. Thepatient was obese (body mass index, 45 kg/m2) with a potentially difficultairway. Without sedative premedication, a low dose spinal anesthetic wasadministered with hyperbaric bupivacaine (10mg) and fentanyl (10 mcg).The patient suffered immediate respiratory arrest, followed by loss ofconsciousness, bradycardia and hypotension consistent with a high spinalblock. These adverse effects reversed within 4 hours and the patient wasdischarged with no sequelae. A possible explanation for this un-anticipated high spinal block in the context of NPH and a VP shuntincludes an increased gradient of cephalad flow of cerebrospinal fluid(CSF) due to a persisting compensatory increase in CSF reabsorptionfrom NPH as well as CSF flow through the shunt. Our case demonstratesthe need to consider the potential for high spinal block in in a patient withNPH and a VP shunt.[SNACC-109] Anesthesia Management for an Adult Patient WithMethylmalonic Aciduria Undergoing Complex Spinal SurgeryAl-Tamimi M, Krovvidi H, Ellahee P, Russo A. Queen Elizabeth Hos-pital Birmingham, Birmingham, United kingdom.Long-term survival of patients with methylmalonic aciduria (MMA) toadulthood has significantly improved nowadays. However, this hasbrought new challenges in anaesthesia management of these patients. Wereport a case of MMA with multiple complications who was successfullyoperated for complex cervical spine surgery in 2 different positions.A 33-year-old male with MMA, metabolic stroke at the age of 8, dys-tonia, contractures, degenerative spinal cord compression and myelo-malacia was admitted for elective cervical spine surgery. Preoperativeinvestigations were satisfactory. Intravenous 10% dextrose with potas-sium was started during fasting period to prevent metabolic acidosis. OnJ Neurosurg Anesthesiol  Volume 29, Number 4, October 2017 AbstractsCopyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. www.jnsa.com | 557Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.

Pupillary pain index correlates with postoperative pain scores in neurosurgical patients

Ferreira, A.

Vide, Sergio

Correia, Rui P.

Nunes, Catarina S.

Amorim, Pedro P.

Bloom, Marc

University of Miami: Scholarship@Miami

Assessment of the opioid effect on the pupillary pain index

Ferreira, A.

rupture. The LMA Protector is a recently introduced SGD (www.lmaco.com/products/lmaAE-protector-airway-cuff-pilot-technology), which al-lows controlled ventilation, provides a gastric access port and features aconduit for endotracheal intubation, if required (Fig. 1).Method: We present a series of 4 cases scheduled for elective endovas-cular aneurysm coiling under general anesthesia where the LMA Pro-tector was used for airway management. Patients included had no historyof aneurysm rupture or subarachnoid hemorrhage. Controlled ventilationwas instituted after device insertion and performance tests verified goodplacement. Patient demographic data, ventilator parameters, and adverseevents are shown in Table.Results: The studies and aneurysm treatments were completed withoutincident and periods of apnea were performed as needed. All patientsemerged quickly from anesthesia with minimal coughing and response tocommands.Conclusions: In carefully selected patients the LMA Protector Airwaycan be an effective alternative to ETT for cerebral aneurysm coiling.Adequate ventilation was achieved and placement of ETT via the devicewas not necessary but could have been performed in case of aneurysmrupture. Further randomized trials are needed to provide validation forthe use of this device.References:1. Carron M, Veronese S, Gomiero W, et al. Anesthesiology. 2012;117(2):309–320.2. Teoh WH, Lee KM, Suhitharan T, et al. Anaesthesia. 2010;65:1173–1179.3. Sharma R, Dua CK, Saxena KN. Singapore Med J. 2011;52(12):874–878.[SNACC-104] Predicting Loss of Consciousness Using the Pupil-lary Light ReflexFerreira A*, Vide S†, Correia R‡, Nunes C§, Amorim P‡. *Faculdade DeEngenharia Do Porto. †Hospital Pedro Hispano, Matosinhos. ‡CentroHospitalar Do Porto. §Universidade Aberta, Porto, Portugal.Background:Defining the moment of loss of consciousness is not a consensual.In the clinical practice it is often assessed using clinical endpoints, but in somestudies, pharmacokinetic or EEG-derived parameters have been used. The as-sessment of clinical endpoints can reflect either cortical, subcortical/brainstemand/or spinal functions. From the several brainstem1 reflexes described, one thatcan eventually be used for this purpose is the Pupillary Light Reflex (PLR).PLR is useful, as it reflects the actions of the anesthetics along the 4 differentJ Neurosurg Anesthesiol  Volume 29, Number 4, October 2017 AbstractsCopyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. www.jnsa.com | 555Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.synapsis of the reflexes across the central nervous system. Opioids affect pupilsize, but do seem not alter light reflex amplitude or constriction velocity andpropofol decrease both the amplitude of the light reflex independently of anychange in pupil size.2In this study, we wanted to assess the possibility of using differentcharacteristics of the PLR to predict loss of consciousness.Methods: This is an observational prospective study, where 25 consec-utive patients were enrolled. Patients scheduled for neurosurgical proce-dures, with general total intravenous anesthesia with propofol andremifentanil were considered when no premedication was used. The PLRwas measured using a portable infrared pupillometer (AlgiScan—IDMed, France) before and after loss of consciousness was achieved. Thepupillometer applied a flash of visible light and measured the minimumdiameter obtained afterwards, the response latency and velocity of con-traction. A logistic regression for loss of consciousness was then calcu-lating using these 3 variables. Data are presented as mean±SD.Results: The logistic regression model showed goodness of fit (Hosmerand Lemeshow test P= 0.921). Velocity of contraction was statisticalsignificant (P< 0.001, Exp(B) 0.98).Receiver operating characteristic curve of the predicted probabilitiesyielded an area under the curve of 0.982 (P< 0.001) (Fig. 1).Discussion: From this preliminary results, it seems that some measurementsrelated to the PLR can be used to detect loss of consciousness. However,further studies are needed to assess if it correlates with the time it ensues.References:1. Bosch L, Fernández-Candila J, León A, et al. Revista Española deAnestesiología y Reanimación. 2017;64:157–167.2. Couret D, Boumaza D, Grisotto C, et al. Crit Car 2016;20:99.[SNACC-105] Pupillary Pain Index correlates with PostoperativePain Scores in Neurosurgical PatientsVide S*, Correia R†, Rego J‡, Soares M†, Nunes C§, Leitão A∥, AmorimP†. *Hospital Pedro Hispano, Matosinhos. †Centro Hospitalar Do Porto.§Universidade Aberta. ∥Faculdade De Engenharia Do Porto, Porto.‡Centro Hospitalar Tamega E Sousa, Penafiel, Portugal.Background: Acute postoperative pain, if inadequately treated, not onlylimits mobility and impairs ventilation, but also increases stress hormonesand the risk for chronic postsurgical pain.1 In contrast, if opioids aregiven in excess they can cause respiratory depression, nausea and vom-iting, ileus, sedation and even hyperalgesia.1Adequate titration of analgesia intraoperatively lacks a widely acceptedmonitor. Nevertheless, some studies have addressed this issue by usingsurrogate variables of the autonomic nervous system to guide opioidadministration.2–3 In this study, we recorded the pupillary dilation re-sponse immediately before extubation and compared it with the ratings ofpatient’s pain reported in the postanesthesia care unit (PACU) using avisual analog scale (VAS).4Methods: Pupillary dilation response was determined through pupillom-etry using AlgiScan and its Pupillary Pain Index (PPI). The PPI consistsin measuring the changes in pupillary dilation in response to a con-tinuously increasing electric stimulus discharge, which then assigns scoresfrom 1 (when pupillary dilation is <5% despite maximal tetanic stim-ulation intensity) to 10 (when pupillary dilation rises above 13% with the10mA).3 Twenty-two patients undergoing neurosurgery were included inthis study. General anesthesia was induced and maintained with propofoland remifentanil, titrated to achieve adequate levels of sedation andanalgesia during the medical procedure. PPI measurements were per-formed after propofol was stopped at the end of surgery and beforeextubation. VAS pain assessment was performed at PACU arrival.Correlation analysis between PPI and VAS was assessed using 2-tailedSpearmen test with significance for P< 0.01. Data are presented asmean±SD.Results: Demographics were: 57± 13 years, 68.3± 9.1 kg, 163±8 cm, 9%ASA I, 82% ASA II, 9% ASA III, 15 females and 7 males. Mean PPIbefore extubation was 6.2± 2.5 and VAS at PACU arrival was 5± 2.6.VAS was correlated with PPI (Spearmen R= 0.57, P= 0.006), and couldbe predicted (adjusted R2= 0.41) as VAS= 0.79×PPI+0.046.Conclusions and Discussion: We found a correlation between pre-extubation PPI and the VAS at PACU arrival. This data suggest that PPIcould be used to titrate analgesia in the end of the intraoperative period,targeting optimal analgesia in the immediate postoperative period.References:1. Larson MD, Sessler DI. Anesthesiology 2012;116(5):980–982.2. Boselli E, Bouvet L, Bégou G, et al. Br J Anaesth. 2014;112(4):715–721.Abstracts J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017556 | www.jnsa.com Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.

Predicting loss of consciousness using the pupillary light reflex

Vide, Sergio

Amorim, Pedro P.

The Repositório Aberto

rupture. The LMA Protector is a recently introduced SGD (www.lmaco.
com/products/lmaAE-protector-airway-cuff-pilot-technology), which al-
lows controlled ventilation, provides a gastric access port and features a
conduit for endotracheal intubation, if required (Fig. 1).
Method: We present a series of 4 cases scheduled for elective endovas-
cular aneurysm coiling under general anesthesia where the LMA Pro-
tector was used for airway management. Patients included had no history
of aneurysm rupture or subarachnoid hemorrhage. Controlled ventilation
was instituted after device insertion and performance tests verified good
placement. Patient demographic data, ventilator parameters, and adverse
events are shown in Table.
Results: The studies and aneurysm treatments were completed without
incident and periods of apnea were performed as needed. All patients
emerged quickly from anesthesia with minimal coughing and response to
commands.
Conclusions: In carefully selected patients the LMA Protector Airway
can be an effective alternative to ETT for cerebral aneurysm coiling.
Adequate ventilation was achieved and placement of ETT via the device
was not necessary but could have been performed in case of aneurysm
rupture. Further randomized trials are needed to provide validation for
the use of this device.
References:
1. Carron M, Veronese S, Gomiero W, et al. Anesthesiology. 2012;117
(2):309–320.
2. Teoh WH, Lee KM, Suhitharan T, et al. Anaesthesia. 2010;65:1173–1179.
3. Sharma R, Dua CK, Saxena KN. Singapore Med J. 2011;52(12):
874–878.
[SNACC-104] Predicting Loss of Consciousness Using the Pupil-
lary Light Reflex
Ferreira A*, Vide S†, Correia R‡, Nunes C§, Amorim P‡. *Faculdade De
Engenharia Do Porto. †Hospital Pedro Hispano, Matosinhos. ‡Centro
Hospitalar Do Porto. §Universidade Aberta, Porto, Portugal.
Background:Defining the moment of loss of consciousness is not a consensual.
In the clinical practice it is often assessed using clinical endpoints, but in some
studies, pharmacokinetic or EEG-derived parameters have been used. The as-
sessment of clinical endpoints can reflect either cortical, subcortical/brainstem
and/or spinal functions. From the several brainstem1 reflexes described, one that
can eventually be used for this purpose is the Pupillary Light Reflex (PLR).
PLR is useful, as it reflects the actions of the anesthetics along the 4 different
J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017 Abstracts
Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. www.jnsa.com | 555
Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.
synapsis of the reflexes across the central nervous system. Opioids affect pupil
size, but do seem not alter light reflex amplitude or constriction velocity and
propofol decrease both the amplitude of the light reflex independently of any
change in pupil size.2
In this study, we wanted to assess the possibility of using different
characteristics of the PLR to predict loss of consciousness.
Methods: This is an observational prospective study, where 25 consec-
utive patients were enrolled. Patients scheduled for neurosurgical proce-
dures, with general total intravenous anesthesia with propofol and
remifentanil were considered when no premedication was used. The PLR
was measured using a portable infrared pupillometer (AlgiScan—
IDMed, France) before and after loss of consciousness was achieved. The
pupillometer applied a flash of visible light and measured the minimum
diameter obtained afterwards, the response latency and velocity of con-
traction. A logistic regression for loss of consciousness was then calcu-
lating using these 3 variables. Data are presented as mean±SD.
Results: The logistic regression model showed goodness of fit (Hosmer
and Lemeshow test P= 0.921). Velocity of contraction was statistical
significant (P< 0.001, Exp(B) 0.98).
Receiver operating characteristic curve of the predicted probabilities
yielded an area under the curve of 0.982 (P< 0.001) (Fig. 1).
Discussion: From this preliminary results, it seems that some measurements
related to the PLR can be used to detect loss of consciousness. However,
further studies are needed to assess if it correlates with the time it ensues.
References:
1. Bosch L, Fernández-Candila J, León A, et al. Revista Española de
Anestesiología y Reanimación. 2017;64:157–167.
2. Couret D, Boumaza D, Grisotto C, et al. Crit Car 2016;20:99.
[SNACC-105] Pupillary Pain Index correlates with Postoperative
Pain Scores in Neurosurgical Patients
Vide S*, Correia R†, Rego J‡, Soares M†, Nunes C§, Leitão A∥, Amorim
P†. *Hospital Pedro Hispano, Matosinhos. †Centro Hospitalar Do Porto.
§Universidade Aberta. ∥Faculdade De Engenharia Do Porto, Porto.
‡Centro Hospitalar Tamega E Sousa, Penafiel, Portugal.
Background: Acute postoperative pain, if inadequately treated, not only
limits mobility and impairs ventilation, but also increases stress hormones
and the risk for chronic postsurgical pain.1 In contrast, if opioids are
given in excess they can cause respiratory depression, nausea and vom-
iting, ileus, sedation and even hyperalgesia.1
Adequate titration of analgesia intraoperatively lacks a widely accepted
monitor. Nevertheless, some studies have addressed this issue by using
surrogate variables of the autonomic nervous system to guide opioid
administration.2–3 In this study, we recorded the pupillary dilation re-
sponse immediately before extubation and compared it with the ratings of
patient’s pain reported in the postanesthesia care unit (PACU) using a
visual analog scale (VAS).4
Methods: Pupillary dilation response was determined through pupillom-
etry using AlgiScan and its Pupillary Pain Index (PPI). The PPI consists
in measuring the changes in pupillary dilation in response to a con-
tinuously increasing electric stimulus discharge, which then assigns scores
from 1 (when pupillary dilation is <5% despite maximal tetanic stim-
ulation intensity) to 10 (when pupillary dilation rises above 13% with the
10mA).3 Twenty-two patients undergoing neurosurgery were included in
this study. General anesthesia was induced and maintained with propofol
and remifentanil, titrated to achieve adequate levels of sedation and
analgesia during the medical procedure. PPI measurements were per-
formed after propofol was stopped at the end of surgery and before
extubation. VAS pain assessment was performed at PACU arrival.
Correlation analysis between PPI and VAS was assessed using 2-tailed
Spearmen test with significance for P< 0.01. Data are presented as
mean±SD.
Results: Demographics were: 57± 13 years, 68.3± 9.1 kg, 163±8 cm, 9%
ASA I, 82% ASA II, 9% ASA III, 15 females and 7 males. Mean PPI
before extubation was 6.2± 2.5 and VAS at PACU arrival was 5± 2.6.
VAS was correlated with PPI (Spearmen R= 0.57, P= 0.006), and could
be predicted (adjusted R2= 0.41) as VAS= 0.79×PPI+0.046.
Conclusions and Discussion: We found a correlation between pre-
extubation PPI and the VAS at PACU arrival. This data suggest that PPI
could be used to titrate analgesia in the end of the intraoperative period,
targeting optimal analgesia in the immediate postoperative period.
References:
1. Larson MD, Sessler DI. Anesthesiology 2012;116(5):980–982.
2. Boselli E, Bouvet L, Bégou G, et al. Br J Anaesth. 2014;112(4):
715–721.
Abstracts J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017
556 | www.jnsa.com Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.
Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.


Ferreira, Ana Isabel Leitão

might help the attending anaesthesiologist to formulate a strategy to allaythe anxiety in these patients. This is the pioneer study highlighting a veryhigh desire for information not only for surgery but also for anaesthesiaamong neurosurgical patients of a developing country. Our study waslimited by recruitment of all the patients from 1 centre so culture andclinic specific factors can alter the findings.[SNACC-120] Evaluation of the PEGASUS Clinical PathwayImplementation on Severe Pediatric Traumatic Brain InjuryPatientsYang J*, King M†, Blayney C†, Johnston B‡, Kim J‡, Vavilala M*,Chesnut R‡. *University of Washington. †Seattle Children’s Hospital.‡Harborview Medical Center, Seattle, WA.Background: Traumatic brain injury (TBI) is a leading cause of disabilityand death and a significant public health problem. Adherence to evidencebased guidelines is associated with improved discharge survival in severepediatric TBI. Three key performance indicators (KPIs), namelyavoidance of unwanted hyperventilation in the absence of herniation,maintenance of all cerebral perfusion pressure (CPP) > 40mmHg, andstart of nutrition within 72 hours, are protective. The Pediatric GuidelineAdherence and Outcomes (PEGASUS) program is a multilevel, im-plementation science guided, comprehensive quality improvement effortdeveloped in 2011 and implemented in 2014 at Harborview MedicalCenter (HMC) that includes clinical protocol (KPIs), value added pro-cesses, and provider perspectives. We hypothesized that implementationof PEGASUS program is associated with improved adherence to KPIsand favorable discharge outcomes.Methods: This is a quasiexperimental, pre-post interventional study. AfterIRB approval, data were extracted from the Harborview Trauma Registryand electronic medical record system. Program phases were Baseline(January 2007 to December 2011), Development (April 2011 to March2014), and Implementation phase (from April 2014 to December, 2016).Inclusion criteria were patients age older than 18 years, TBI, admissionGlasgow Coma Scale (GCS) <9, and abnormal head CT. Patients admittedwith less than severe TBI but who deteriorated were included. KPI ad-herence and favorable discharge disposition (discharge home or re-habilitation) were examined across PEGASUS phases. χ2 and Student t testwere used for univariate tests. P-values are compared with baseline phase.Results: A total of 56 patients from baseline phase (5 y), 103 patients fromdevelopment phase (3 y), and 89 patients from implementation phase(2.75 y) were identified. Avoidance of unwanted hyperventilation in-creased from 12.5% to 61% and 69.2% (both P< 0.0001), all CPPmaintained > 40mmHg remained the same at 69.6%, 62% (P= 0.23),and 60% (P= 0.14), Nutrition initiation within 72 hours increased non-significantly from baseline at 91.1%, to 84% (P= 0.13), and finally to94.2% (P= 0.42). Favorable discharge disposition increased from 55.4%to 70.3% (P= 0.03) and 71.9% (0.01).Discussion: Implementation of the PEGASUS program increased ad-herence to the ventilation KPI and improved discharge outcome. Thechange in nutrition was less sensitive to PEGASUS program im-plementation, possibly due to relatively high baseline adherence rate.CPP maintenance rates did not change but efforts made to increase CPPwere noted by nursing staff.[SNACC-121] Towards Personalized Anesthesia: Predictive Fac-tors for Propofol Requirements for Loss of ConsciousnessNunes C*, Leitao Ferreira A†, Correia R‡, Amorim P‡. *UniversidadeAberta. †Universidade Do Porto. ‡Centro Hospitalar Do Porto, Porto,Portugal.The importance of personalized medicine is becoming increasingly rec-ognized. We previously reported a wide variability in individual patientpropofol requirements for loss of consciousness (LOC).1 The aim of thisstudy was to identify the physiologic variables that may contribute to theobserved interindividual variability.Data of 217 adult patients submitted to neurosurgical procedures wereretrospectively analyzed. Only patients submitted to TIVA with propofoland remifentanil were considered. In all cases 1% propofol was infused ata slow rate (around 200mL/h) with a TCI pump, to allow the preciseidentification of the amount required for LOC. LOC was identified aslack of eye opening to name calling and a tap on the forehead. Variablesconsidered for analysis were: age, weight, height, lean body mass, sex,ASA status, type of surgery, baseline arterial pressure, baseline heart rateand baseline BIS value. The amount of propofol (mg) required for LOC,the propofol predicted effect-site concentration (EC ug/mL) at LOC(Schnider’s PK model), and the induction sequence (propofol or opioidfirst) were also noted. Multivariate Regression Analysis was used to de-termine if any of the patient data and baseline recordings were predictorsof the propofol amount (mg or mg/kg) required for LOC, or of thepredicted propofol EC at LOC.The propofol EC ug/mL at LOC: IQ range (3.1 to 5.3) (71%). The totalamount of propofol in mg at LOC: IQ range (71.8 to 116.3) (62%).Propofol for LOC in mg/kg: IQ range (1.1 to 1.7) (55%).The identified independent predictive factors for the propofol EC at LOCwere: sex (P< 0.001) and baseline SAP (P< 0.001), with R2= 0.25(P< 0.001). For the propofol total amount in milligrams required forLOC the identified independent predictive factors were: age (P< 0.001),sex (P= 0.018), weight (P= 0.009), and baseline SAP (P< 0.001), withR2= 0.31 (P< 0.001). For the propofol total amount in mg/kg the in-dependent predictive factors were: age (P< 0.001), sex (P= 0.045), weight(P< 0.001) and baseline SAP (P< 0.001), with R2= 0.3 (P< 0.001). Forall, the female sex and age decreased the propofol requirements, whilehigher SAP baseline values increased the propofol requirements.We show a wide variability in individual patient propofol requirements toinduce LOC, which is critical. This variability was observed even whenEC were used, although PK models already incorporate sex, age, weight,J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017 AbstractsCopyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. www.jnsa.com | 563Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.and height. Interestingly, the baseline SAP and sex, proved to be in-dependent predictive factors and explained at least 25% of the variability.Acknowledgements: LAETA-INEGI; FCT: SFRH/BD/98915/2013.Reference:1. Walia H, Schloss B, Tobias J. Proceedings from the American Societyof Anesthesiologists; 2015. Abstract 4151.[SNACC-122] A Survey Assessing Attitudes Regarding Neuro-anesthesia Fellowship Amongst Attending Anesthesiologists, Fel-lows and ResidentsRajan S*, Theard M†, Easdown J‡, Pasternak J§. *Cleveland Clinic,Cleveland, OH. †Oregon Anesthesiology Group, Portland, OR. ‡4648 theVanderbilt Clinic, Nashville, TN. §Mayo Clinic, Rochester, MN.Background: Despite advances in the exciting field of neuro-anesthesiology, the number of residents applying for a neuroanesthesiafellowship is still low compared with other anesthesiology fellowshipprograms. We conducted a survey on behalf of the Society for Neuro-science in Anesthesiology and Critical Care (SNACC) NeuroanesthesiaEducation Special Interest Group (SIG) to assess attitudes regardingneuroanesthesia fellowship training.Methods: The survey was administered to all e-mail addresses containedwithin SNACC’s database and was also administered to members ofthe Society for Education in Anesthesiology (SEA) and the Society ofAcademic Anesthesiology Associations (SAAA). Additionally, membersof the SNACC board of directors were asked to distribute the survey toAbstracts J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017564 | www.jnsa.com Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.

Towards personalized anesthesia: predictive factors for propofol requirements for loss of consciousness

Vide S*, Correia R†, Amorim P†, Nunes C‡. *Hospital Pedro Hispano,Matosinhos. †Centro Hospitalar Do Porto, Porto, Portugal. ‡UniversidadeAberta, Porto, Portugal.Background: The importance of personalized medicine is becomingincreasingly recognized in anesthesia. Titration of the different drugsused in anesthesiology has become possible due to monitors that allowus to measure the different effects. However, regarding the analgesiceffect, there are not many available solutions yet. The Pupillary ReflexDilation has been studied as a surrogate for measuring the nociception/antinociception balance of patients, both in the operating theater aswell as in intensive care.1 The aim of this study was to assess thePupillary Pain Index (PPI) association with different concentrations ofremifentanil.Methods: This was an observational prospective study, where 34 con-secutive patients were enrolled. Patients scheduled for neurosurgicalprocedures, with general TIVA anesthesia with propofol and remifentanilwere considered when no premedication was used. Induction began withan infusion of remifentanil targeted for a constant concentration usingMinto PK Model and then an infusion of propofol at 200mL/h wasstarted until loss of consciousness was observed. Afterwards, an infraredportable pupillometer (AlgiScan—IDMed, France) was used to assess thePupillary Dilation Reflex and its derived index PPI. Following thismeasurement, remifentanil concentrations could be increased or de-creased if deemed necessary by the anesthesiologist. The PPI consists inmeasuring the pupillary dilation in response to a continuously increasingelectric stimulus discharge, that stops when > 13% dilation from baselineis achieved, or when 60mA is reached. PPI measurements were takenafter loss of consciousness and before surgery, at moments when no otherstimulus were present. For each measure of PPI the predicted effect-siteconcentration (EC) of remifentanil (Minto PK model) and of propofol(Schnider PK Model); and the BIS value were noted. Data are mean±SD or %.Results: A total of 78 measures of PPI were done. Patients’ data were:57± 15 years; 73± 21 kg; 162±8 cm; 60% female; 11.5% ASA I; 80.8%ASA II; Remifentanil EC 2.4± 1.5 ng/mL; propofol EC 3.7± 1.3 ug/mL;BIS 46.1± 8.2; PPI 4.8 ± 3. A correlation was observed between the re-mifentanil EC and PPI (R=−0.46, P< 0.001), but not between PPI andpropofol EC or BIS. A correlation was observed between BIS and pro-pofol CE (R=−0.26, P= 0.028), but not with remifentanil. Tukey HSDtest showed that the different is mainly due to concentrations <3 versus≥ 3 ng/mL.Conclusions: We found a significant correlation between the remifentanilconcentration and PPI, showing that PPI discriminates different levels ofanalgesia. No correlation was found with propofol or BIS. However,there was no clear discrimination between all levels of remifentanil con-centrations analyzed. Further research should be done, with more dataand more stratified levels of remifentanil.ACK: LAETA-INEGI.Reference:1. Barvais L, Engelman E, Eba JM, et al. Br J Anaesth. 2003;91:347–352.[SNACC-50] Analgesic Interpatient Variability of RemifentanilAssessed Through Pupillary Dilation ReflexVide S*, Correia R†, Nunes C‡, Amorim P†. *Hospital Pedro Hispano,Matosinhos. †Centro Hospitalar Do Porto. ‡Universidade Aberta, Porto,Portugal.Background: Although there has been significant focus on unconsciousnessand amnesia, identifying the neural signatures of effective analgesia has re-ceived less attention.1 Currently, appraisal of intraoperative nociception ismostly done through the assessment of the autonomic response to noxiousstimuli, whether it is through heart rate variability, heartbeat intervals, ple-thysmographic pulse wave amplitude, skin conductance or pupillary re-sponse.2 The known wide inter-patient variability of the hypnotic effect,namely in the amount of propofol needed to achieve loss of consciousness, ledus to question if this variability also happened for the analgesic effect. In thisJ Neurosurg Anesthesiol  Volume 29, Number 4, October 2017 AbstractsCopyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. www.jnsa.com | 523Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.study, we evaluated the interpatient variability of the Pupillary Dilation Reflex(PDR) response to different levels of remifentanil, administered using targetcontrolled infusion with the Minto Pk Model.Methods: This is an observational prospective study, where 34 consecutivepatients were enrolled. Patients scheduled for neurosurgical procedures, withTIVA (using target controlled infusion systems) with propofol and re-mifentanil were considered when no premedication was used. Induction beganwith a constant remifentanil concentration using Minto PK Model and thenan infusion of propofol at 200mL/h was started until loss of consciousnesswas observed. Afterwards, an infrared portable pupillometer (AlgiScan—IDMed, France) was used to assess the Pupillary Dilation Reflex and itsderived index Pupillary Pain Index (PPI). Remifentanil concentrations couldbe increased if deemed necessary by the anesthesiologist. The PPI is calculatedfrom the PDR to a continuously increasing electric stimulus discharge. PPImeasurements were taken after loss of consciousness and before surgery, atmoments when no other stimulus were present. For each measure of PPI thepredicted effect-site concentration (EC) of remifentanil and of propofol(Schnider PK Model); Data are mean±SD or %.Results: Thirty-four consecutive patients were enrolled, and a total of78 measures of PPI were done. Figure 1 shows the PPI variability fordifferent levels of remifentanil EC and Table 1 shows the PPI values forthe four levels of remifentanil. The variability found ranged from 80% to500%, depending on the effect site concentration of remifentanil. Thehigher the concentration, the larger the variability. The mean PPI is thedifference between the different Remifentanil EC levels (ANOVAP< 0.001).Conclusions: The variability of the analgesic effect was as high as 500%.This suggests that more attention should be paid to the individualizationof intraoperative analgesia, as different patients have different analgesicneeds, and these need cannot be predicted only through PK-PD models.Further research should be done, with more data and more stratifiedlevels of remifentanil.ACK: LAETA-INEGI.References:1. Mashour GA. Anesthesiology. 2013;118:239–240.2. Edry R, Recea V, Dikust Y, et al. Anesthesiology. 2016;125:193–203.[SNACC-51] The Effect of Sevoflurane-Air Versus Sevoflurane-Nitrous Oxide Anesthesia on Length of ICU and Hospital Stayin Patients Undergoing Cerebellopontine Tumour Surgery: ARandomized Controlled TrialBindu B, Pandia M, Singh G. All India Institute of Medical Sciences, NewDelhi, Delhi, India.Background: Nitrous oxide (N2O), a unique anaesthetic agent, has bothadvantages and disadvantages, especially in neurosurgical patients.Various studies evaluating the use of N2O in different surgical pop-ulations have been inconclusive so far.Objectives: To compare duration of ICU and hospital stay in patientsreceiving sevoflurane based general anesthesia with/without N2O, for elec-tive cerebellopontine angle (CPA) tumor excision surgery. Secondarily, weAbstracts J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017524 | www.jnsa.com Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.

Analgesic interpatient variability of remifentanil assessed through pupillary dilation reflex

analysis for MTNR1B receptor SNP, rs10830963, as part of a larger
study. Using a validated method, CHART-DEL, all charts were reviewed
and scored for the likelihood of delirium without knowledge of the results
of the MTNR1B gene polymorphism. CHART-DEL has a sensitivity of
74%, specificity of 83%.5,6 It was decided a priori patients rated as
probable and definite delirium would be categorized as having delirium.
The Fisher exact was used for analysis.
Results: Genotyping for the MTNR1B gene was acceptable in 80 subjects
of which 18 (22.5%) had delirium. Four (57.1%) of patients with the risk
genotype had delirium versus only 14 (19.2%) without the genotype,
P= 0.04.
Conclusions: Although our study was limited to cardiac surgery, has
relatively small sample size, and retrospectively assessed for the pres-
ence of delirium, the significant correlation of the risk geno-
type of the MTNR1B melatonin receptor with delirium is intriguing and
warrants further prospective studies. Our data supports a role for the
MTNR1B melatonin receptor in the pathogenesis of postoperative
delirium.
Supported by NIH grants 1R21NS061074-01A2 and T32 GM112596.
References:
1. Guenther U, Theuerkauf N, Frommann I, et al. Ann Surg. 2013;257
(6):1160–1167.
2. Gosselt AN, Slooter AJ, Boere PR, et al. Crit Care 2015;19:346.
3. de Jonghe A, de Rooij S, Tanck MWT, et al. Dement Geriatr Cogn
Disord. 2012;33(5):306–310.
4. Hu C, Jia W. Diabetes. 2016;65(6):1490–1492.
5. Inouye SK, Leo-Summers L, Zhang Y, et al. J Am Geriatr Soc.
2005;53(2):312–318.
6. Saczynski JS, Kosar CM, Xu G, et al. J Am Geriatr Soc. 2014;62
(3):518–524.
[SNACC-48] The Impact of Hypotension During Stroke Inter-
vention May Depend on Type of Anesthesia and Stroke Severity
Tang L, Whalin M. Emory University School of Medicine, Atlanta, GA.
Introduction: Recent studies have linked intraprocedural hypotension to
poor neurological outcomes in stroke patients receiving thrombectomies
under both monitored anesthetic care (MAC)1 and general anesthesia
(GA).2 The GA study included only 60 patients so those authors were
unable to examine blood pressure thresholds for GA patients. We hy-
pothesized that decreases in MAP would have a similar effect in patients
whether they received MAC or GA.
Methods: We retrospectively examined patients who were successfully
reperfused (modified thrombolysis in cerebral infarction scores of 2b or 3)
at our institution from 2010 until 2015. We identified 439 such patients
with complete anesthetic, hemodynamic, and outcome data. Percentage
MAP drop was defined based on the change from baseline to the lowest
recorded MAP before mTICI 2b/3 reperfusion. Stroke severity was based
on the admission NIH stroke scale (NIHSS) score. Good outcome was
defined as a modified Rankin score (mRS) at 90 days of 0 to 2, which
corresponds to functional independence.
Results: In our cohort the rate of good outcome was 58% in the 297
patients who received MAC and 39% in the 142 patients who received
GA. MAP fell more than 20% from baseline in 62% of MAC cases and
84% of GA cases. As shown in the figure, in patients with strokes of
intermediate severity (NIHSS 16 to 20) keeping MAP within 10% of
baseline was associated with substantially more good outcomes for both
GA and MAC patients. In those with severe strokes (NIHSS> 20) tight
hemodynamic control appeared to have a smaller impact on outcome for
both anesthetic groups. For less severe strokes (NIHSS< 16) hypotension
appeared to have a more profound impact for GA patients than for MAC
patients.
Conclusions: Maintaining MAP within 10% of baseline was associated
with higher rates of good outcome in all subgroups studied. Our analysis
was limited by the small proportion of patients who maintained MAP
within 10% of baseline, especially in the GA group. However, such tight
hemodynamic control seemed to be particularly beneficial to all patients
with NIHSS 16 to 20 and patients with NIHSS< 16 who received GA.
Anesthesiologists should try to maintain MAP within 10% of baseline
values for both MAC and GA cases.
References:
1. Whalin MK, Halenda KM, Haussen DC, et al. AJNR Am J Neuro-
radiol. 2017;38(2):294–298.
2. Treurniet KM, Berkhemer OA, Vlmmink RV, et al. J Neurointerv Surg.
2017. Doi:10.1136/neurintsurg-2017-012988. [Epub ahead of print].
[SNACC-49] Assessment of the Opioid Effect on the Pupillary
Pain Index
Abstracts J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017
522 | www.jnsa.com Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.
Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.
Vide S*, Correia R†, Amorim P†, Nunes C‡. *Hospital Pedro Hispano,
Matosinhos. †Centro Hospitalar Do Porto, Porto, Portugal. ‡Universidade
Aberta, Porto, Portugal.
Background: The importance of personalized medicine is becoming
increasingly recognized in anesthesia. Titration of the different drugs
used in anesthesiology has become possible due to monitors that allow
us to measure the different effects. However, regarding the analgesic
effect, there are not many available solutions yet. The Pupillary Reflex
Dilation has been studied as a surrogate for measuring the nociception/
antinociception balance of patients, both in the operating theater as
well as in intensive care.1 The aim of this study was to assess the
Pupillary Pain Index (PPI) association with different concentrations of
remifentanil.
Methods: This was an observational prospective study, where 34 con-
secutive patients were enrolled. Patients scheduled for neurosurgical
procedures, with general TIVA anesthesia with propofol and remifentanil
were considered when no premedication was used. Induction began with
an infusion of remifentanil targeted for a constant concentration using
Minto PK Model and then an infusion of propofol at 200mL/h was
started until loss of consciousness was observed. Afterwards, an infrared
portable pupillometer (AlgiScan—IDMed, France) was used to assess the
Pupillary Dilation Reflex and its derived index PPI. Following this
measurement, remifentanil concentrations could be increased or de-
creased if deemed necessary by the anesthesiologist. The PPI consists in
measuring the pupillary dilation in response to a continuously increasing
electric stimulus discharge, that stops when > 13% dilation from baseline
is achieved, or when 60mA is reached. PPI measurements were taken
after loss of consciousness and before surgery, at moments when no other
stimulus were present. For each measure of PPI the predicted effect-site
concentration (EC) of remifentanil (Minto PK model) and of propofol
(Schnider PK Model); and the BIS value were noted. Data are mean±
SD or %.
Results: A total of 78 measures of PPI were done. Patients’ data were:
57± 15 years; 73± 21 kg; 162±8 cm; 60% female; 11.5% ASA I; 80.8%
ASA II; Remifentanil EC 2.4± 1.5 ng/mL; propofol EC 3.7± 1.3 ug/mL;
BIS 46.1± 8.2; PPI 4.8 ± 3. A correlation was observed between the re-
mifentanil EC and PPI (R=−0.46, P< 0.001), but not between PPI and
propofol EC or BIS. A correlation was observed between BIS and pro-
pofol CE (R=−0.26, P= 0.028), but not with remifentanil. Tukey HSD
test showed that the different is mainly due to concentrations <3 versus
≥ 3 ng/mL.
Conclusions: We found a significant correlation between the remifentanil
concentration and PPI, showing that PPI discriminates different levels of
analgesia. No correlation was found with propofol or BIS. However,
there was no clear discrimination between all levels of remifentanil con-
centrations analyzed. Further research should be done, with more data
and more stratified levels of remifentanil.
ACK: LAETA-INEGI.
Reference:
1. Barvais L, Engelman E, Eba JM, et al. Br J Anaesth. 2003;91:347–352.
[SNACC-50] Analgesic Interpatient Variability of Remifentanil
Assessed Through Pupillary Dilation Reflex
Vide S*, Correia R†, Nunes C‡, Amorim P†. *Hospital Pedro Hispano,
Matosinhos. †Centro Hospitalar Do Porto. ‡Universidade Aberta, Porto,
Portugal.
Background: Although there has been significant focus on unconsciousness
and amnesia, identifying the neural signatures of effective analgesia has re-
ceived less attention.1 Currently, appraisal of intraoperative nociception is
mostly done through the assessment of the autonomic response to noxious
stimuli, whether it is through heart rate variability, heartbeat intervals, ple-
thysmographic pulse wave amplitude, skin conductance or pupillary re-
sponse.2 The known wide inter-patient variability of the hypnotic effect,
namely in the amount of propofol needed to achieve loss of consciousness, led
us to question if this variability also happened for the analgesic effect. In this
J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017 Abstracts
Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. www.jnsa.com | 523
Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.


analysis for MTNR1B receptor SNP, rs10830963, as part of a largerstudy. Using a validated method, CHART-DEL, all charts were reviewedand scored for the likelihood of delirium without knowledge of the resultsof the MTNR1B gene polymorphism. CHART-DEL has a sensitivity of74%, specificity of 83%.5,6 It was decided a priori patients rated asprobable and definite delirium would be categorized as having delirium.The Fisher exact was used for analysis.Results: Genotyping for the MTNR1B gene was acceptable in 80 subjectsof which 18 (22.5%) had delirium. Four (57.1%) of patients with the riskgenotype had delirium versus only 14 (19.2%) without the genotype,P= 0.04.Conclusions: Although our study was limited to cardiac surgery, hasrelatively small sample size, and retrospectively assessed for the pres-ence of delirium, the significant correlation of the risk geno-type of the MTNR1B melatonin receptor with delirium is intriguing andwarrants further prospective studies. Our data supports a role for theMTNR1B melatonin receptor in the pathogenesis of postoperativedelirium.Supported by NIH grants 1R21NS061074-01A2 and T32 GM112596.References:1. Guenther U, Theuerkauf N, Frommann I, et al. Ann Surg. 2013;257(6):1160–1167.2. Gosselt AN, Slooter AJ, Boere PR, et al. Crit Care 2015;19:346.3. de Jonghe A, de Rooij S, Tanck MWT, et al. Dement Geriatr CognDisord. 2012;33(5):306–310.4. Hu C, Jia W. Diabetes. 2016;65(6):1490–1492.5. Inouye SK, Leo-Summers L, Zhang Y, et al. J Am Geriatr Soc.2005;53(2):312–318.6. Saczynski JS, Kosar CM, Xu G, et al. J Am Geriatr Soc. 2014;62(3):518–524.[SNACC-48] The Impact of Hypotension During Stroke Inter-vention May Depend on Type of Anesthesia and Stroke SeverityTang L, Whalin M. Emory University School of Medicine, Atlanta, GA.Introduction: Recent studies have linked intraprocedural hypotension topoor neurological outcomes in stroke patients receiving thrombectomiesunder both monitored anesthetic care (MAC)1 and general anesthesia(GA).2 The GA study included only 60 patients so those authors wereunable to examine blood pressure thresholds for GA patients. We hy-pothesized that decreases in MAP would have a similar effect in patientswhether they received MAC or GA.Methods: We retrospectively examined patients who were successfullyreperfused (modified thrombolysis in cerebral infarction scores of 2b or 3)at our institution from 2010 until 2015. We identified 439 such patientswith complete anesthetic, hemodynamic, and outcome data. PercentageMAP drop was defined based on the change from baseline to the lowestrecorded MAP before mTICI 2b/3 reperfusion. Stroke severity was basedon the admission NIH stroke scale (NIHSS) score. Good outcome wasdefined as a modified Rankin score (mRS) at 90 days of 0 to 2, whichcorresponds to functional independence.Results: In our cohort the rate of good outcome was 58% in the 297patients who received MAC and 39% in the 142 patients who receivedGA. MAP fell more than 20% from baseline in 62% of MAC cases and84% of GA cases. As shown in the figure, in patients with strokes ofintermediate severity (NIHSS 16 to 20) keeping MAP within 10% ofbaseline was associated with substantially more good outcomes for bothGA and MAC patients. In those with severe strokes (NIHSS> 20) tighthemodynamic control appeared to have a smaller impact on outcome forboth anesthetic groups. For less severe strokes (NIHSS< 16) hypotensionappeared to have a more profound impact for GA patients than for MACpatients.Conclusions: Maintaining MAP within 10% of baseline was associatedwith higher rates of good outcome in all subgroups studied. Our analysiswas limited by the small proportion of patients who maintained MAPwithin 10% of baseline, especially in the GA group. However, such tighthemodynamic control seemed to be particularly beneficial to all patientswith NIHSS 16 to 20 and patients with NIHSS< 16 who received GA.Anesthesiologists should try to maintain MAP within 10% of baselinevalues for both MAC and GA cases.References:1. Whalin MK, Halenda KM, Haussen DC, et al. AJNR Am J Neuro-radiol. 2017;38(2):294–298.2. Treurniet KM, Berkhemer OA, Vlmmink RV, et al. J Neurointerv Surg.2017. Doi:10.1136/neurintsurg-2017-012988. [Epub ahead of print].[SNACC-49] Assessment of the Opioid Effect on the PupillaryPain IndexAbstracts J Neurosurg Anesthesiol  Volume 29, Number 4, October 2017522 | www.jnsa.com Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.Vide S*, Correia R†, Amorim P†, Nunes C‡. *Hospital Pedro Hispano,Matosinhos. †Centro Hospitalar Do Porto, Porto, Portugal. ‡UniversidadeAberta, Porto, Portugal.Background: The importance of personalized medicine is becomingincreasingly recognized in anesthesia. Titration of the different drugsused in anesthesiology has become possible due to monitors that allowus to measure the different effects. However, regarding the analgesiceffect, there are not many available solutions yet. The Pupillary ReflexDilation has been studied as a surrogate for measuring the nociception/antinociception balance of patients, both in the operating theater aswell as in intensive care.1 The aim of this study was to assess thePupillary Pain Index (PPI) association with different concentrations ofremifentanil.Methods: This was an observational prospective study, where 34 con-secutive patients were enrolled. Patients scheduled for neurosurgicalprocedures, with general TIVA anesthesia with propofol and remifentanilwere considered when no premedication was used. Induction began withan infusion of remifentanil targeted for a constant concentration usingMinto PK Model and then an infusion of propofol at 200mL/h wasstarted until loss of consciousness was observed. Afterwards, an infraredportable pupillometer (AlgiScan—IDMed, France) was used to assess thePupillary Dilation Reflex and its derived index PPI. Following thismeasurement, remifentanil concentrations could be increased or de-creased if deemed necessary by the anesthesiologist. The PPI consists inmeasuring the pupillary dilation in response to a continuously increasingelectric stimulus discharge, that stops when > 13% dilation from baselineis achieved, or when 60mA is reached. PPI measurements were takenafter loss of consciousness and before surgery, at moments when no otherstimulus were present. For each measure of PPI the predicted effect-siteconcentration (EC) of remifentanil (Minto PK model) and of propofol(Schnider PK Model); and the BIS value were noted. Data are mean±SD or %.Results: A total of 78 measures of PPI were done. Patients’ data were:57± 15 years; 73± 21 kg; 162±8 cm; 60% female; 11.5% ASA I; 80.8%ASA II; Remifentanil EC 2.4± 1.5 ng/mL; propofol EC 3.7± 1.3 ug/mL;BIS 46.1± 8.2; PPI 4.8 ± 3. A correlation was observed between the re-mifentanil EC and PPI (R=−0.46, P< 0.001), but not between PPI andpropofol EC or BIS. A correlation was observed between BIS and pro-pofol CE (R=−0.26, P= 0.028), but not with remifentanil. Tukey HSDtest showed that the different is mainly due to concentrations <3 versus≥ 3 ng/mL.Conclusions: We found a significant correlation between the remifentanilconcentration and PPI, showing that PPI discriminates different levels ofanalgesia. No correlation was found with propofol or BIS. However,there was no clear discrimination between all levels of remifentanil con-centrations analyzed. Further research should be done, with more dataand more stratified levels of remifentanil.ACK: LAETA-INEGI.Reference:1. Barvais L, Engelman E, Eba JM, et al. Br J Anaesth. 2003;91:347–352.[SNACC-50] Analgesic Interpatient Variability of RemifentanilAssessed Through Pupillary Dilation ReflexVide S*, Correia R†, Nunes C‡, Amorim P†. *Hospital Pedro Hispano,Matosinhos. †Centro Hospitalar Do Porto. ‡Universidade Aberta, Porto,Portugal.Background: Although there has been significant focus on unconsciousnessand amnesia, identifying the neural signatures of effective analgesia has re-ceived less attention.1 Currently, appraisal of intraoperative nociception ismostly done through the assessment of the autonomic response to noxiousstimuli, whether it is through heart rate variability, heartbeat intervals, ple-thysmographic pulse wave amplitude, skin conductance or pupillary re-sponse.2 The known wide inter-patient variability of the hypnotic effect,namely in the amount of propofol needed to achieve loss of consciousness, ledus to question if this variability also happened for the analgesic effect. In thisJ Neurosurg Anesthesiol  Volume 29, Number 4, October 2017 AbstractsCopyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. www.jnsa.com | 523Copyright r 2017 Wolters Kluwer Health, Inc. All rights reserved.

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Analgesic interpatient variability of remifentanil assessed through pupillary dilation reflex

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