J Neurosurg Anesthesiol
Correspondence
Volume 27, Number 4, October 2015
FIGURE 1. A, Inspiratory CO2 (ICO2) and end-tidal CO2 (ETCO2) values while patient’s face is covered by the surgical drapes. B, Immediate reduction in the ICO/ETCO2 to 1 mm Hg and EtCO2 to 32 mm Hg after using blower from the forced air warmer. C, Stabilization of ICO2, ETCO2, and respiratory rate (RR) during rest of the procedure. D, Forced air patient warming system hose placed under the drapes to aerate the patient’s face and blow away the CO2.
and increased patient cooperation. By applying this simple technique, we were able to prevent patient discomfort and reduce the potential of an intraoperative crisis. Dhritiman Chakrabarti, MBBS, MD* Sriganesh Kamath, MBBS, MD, DNB, DM* Mayur V. Kaku, MBBSw Departments of *Neuroanaesthesia wNeurosurgery, National Institute of Mental Health and Neuro Sciences Bangalore, Karnataka, India
Dexmedetomidine Sedation for WADA Test With Intracarotid Propofol in Pediatric Patients To JNA Readers: WADA test (intracarotid amobartbital procedure) remains the “gold standard” when the language and memory lateralization cannot be determined by the noninvasive methods.1 The procedure involves transfemoral catheterization of the carotid artery followed by administration of shortacting anesthetic agent into one of the cerebral hemispheres and assessing the language and memory functions of The authors have no funding or conflicts of interest to disclose.
352 | www.jnsa.com
awake contralateral hemisphere. The procedure is usually carried out with local anesthetic only, as sedation may interfere with memory test results. Performing WADA test in pediatric patients may be challenging and they often require sedation especially during femoral arterial cannulation. Midazolam and propofol are the commonly used sedatives and both have a profound effect on the memory. In addition, due to the nonavailability of amobarbital, propofol is an alternative agent for intracarotid administration for WADA test.1 We report 2 cases of successful use of dexmedetomidine sedation in pediatric patients (6-y-old male and 7-yold female) during selective middle cerebral artery WADA test with intracarotid propofol. Both the children suffered from refractory complex partial seizures localized to right side and resective procedure was planned. Parents stayed with the patients during the entire testing. Intravenous access was established after topical application of EMLA cream. After standard monitoring including 16-channel EEG, both the patients received intravenous dexmedetomidine 1 mg/kg bolus over 10 minutes followed by an infusion at a rate of 0.5 to 0.8 mg/kg/h. Sedation was titrated to OAA/S (Observer’s assessment of alertness/sedation) scale of 2 to 3. After optimal sedation and local anesthetic infiltration, right femoral arterial catheterization was done. Dexmedetomidine infusion was then stopped in the first patient but continued at Copyright
r
the rate of 0.2 mg/kg/h in the second child during the neurophysiological assessment because of her developmental delay. Both patients had a successful language lateralization. To our knowledge this is the first report on the use of dexmedetomidine sedation for pediatric WADA test. Ideal agent for sedation during WADA test should have rapid onset and offset of sedation, with minimal effects on EEG and memory assessment. Propofol sedation has been described for pediatric WADA testing.2 However, propofol-induced amnesia has been described in children which may be a confounding factor in the memory testing.3 Propofol has also been shown to cause EEG spikes in patients with epilepsy.4 Unique properties of dexmedetomidine make it a favorable sedative agent for this patient population. The well-documented beneficial effects of dexmedetomidine are anxiolysis, analgesia, sedation, and sympatholysis, and it is not associated with respiratory depressive effect. Dexmedetomidine sedation is routinely used in the pediatric patients undergoing continuous EEG in epilepsy monitoring unit, as it does not influence EEG recording in the clinical sedative doses and amnesic effect is shown to be significantly less with dexmedetomidine.3,5 These properties of dexmedetomidine helped us successfully test our pediatric patients for language and memory. However, future welldesigned prospective clinical studies
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
J Neurosurg Anesthesiol
Volume 27, Number 4, October 2015
are needed to investigate the influence of dexmedetomidine sedation on EEG and neuropsychological assessment of pediatric patients during WADA testing. Suparna Bharadwaj, MD, DM Lashmi Venkatraghavan, MD, FRCA, FRCPC Department of Anesthesia, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
REFERENCES 1. Patel A, Wordell C, Szarlej D. Alternatives to Sodium amobarbital in the WADA test. Ann Pharmacother. 2011;45:395–401. 2. Masters LT, Perrine K, Devinsky O, et al. WADA testing in pediatric patients by use of propofol anesthesia. AJNR Am J Neuroradiol. 2000;21:1302–1305. 3. Veselis RA, Reinsel RA, Feshchenko VA, et al. Information loss over time defines the memory defect of propofol: a comparative
response with thiopental and dexmedetomidine. Anesthesiology. 2004;101:831–841. 4. Wang B, Bai Q, Jiao X, et al. Effect of sedative and hypnotic doses of propofol on the EEG activity of patients with or without a history of seizure disorders. J Neurosurg Anesthesiol. 1997;9:335–340. 5. Mason KP, O’Mahony E, Zurakowski D, et al. Effects of dexmedetomidine sedation on the EEG in children. Paediatr Anaesth. 2009;19:1175–1183.
Influence of Strapping of the Hand on Noninvasive Hemoglobin Measurements To JNA Readers: Safe positioning is one of the integral aspects of anesthetic practice. It involves padding and strapping to
Correspondence
protect the patient and prevent extreme positioning of the limbs, head, and neck. We report an interesting observation made while using the Masimo Rad-7 noninvasive hemoglobin (NIHb) measurement (Masimo SET Radical-7, Masimo Corp., CA) that resulted from strapping of the hands. Patient consent was obtained before writing this report. The patient was a 67-year-old man undergoing surgery for foramen magnum meningioma in the prone position. Standard monitoring was applied, including invasive blood pressure monitoring in the left radial artery. An NIHb monitor was attached to the right index finger after the patient was positioned prone with straps and with appropriate padding (Fig. 1E). Two straps were applied to secure the patient, across the arms to the thorax and from the hands to the
FIGURE 1. Change in hemoglobin concentration (solid white box) and perfusion index (dashed white box) before (first row) and after (second row) foam padding removal, as ascertained from the index finger (A), the third finger (B), the fourth finger (C), and the fifth finger (D). Hand of the patient with foam padding (E) and without foam padding (F). C.D.: Initial observation, manuscript preparation; B.V. and B.S.D.: manuscript preparation. The authors have no funding or conflicts of interest to disclose.
Copyright
r
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.jnsa.com |
353
Correspondence
Volume 27, Number 4, October 2015
FIGURE 1. A, Inspiratory CO2 (ICO2) and end-tidal CO2 (ETCO2) values while patient’s face is covered by the surgical drapes. B, Immediate reduction in the ICO/ETCO2 to 1 mm Hg and EtCO2 to 32 mm Hg after using blower from the forced air warmer. C, Stabilization of ICO2, ETCO2, and respiratory rate (RR) during rest of the procedure. D, Forced air patient warming system hose placed under the drapes to aerate the patient’s face and blow away the CO2.
and increased patient cooperation. By applying this simple technique, we were able to prevent patient discomfort and reduce the potential of an intraoperative crisis. Dhritiman Chakrabarti, MBBS, MD* Sriganesh Kamath, MBBS, MD, DNB, DM* Mayur V. Kaku, MBBSw Departments of *Neuroanaesthesia wNeurosurgery, National Institute of Mental Health and Neuro Sciences Bangalore, Karnataka, India
Dexmedetomidine Sedation for WADA Test With Intracarotid Propofol in Pediatric Patients To JNA Readers: WADA test (intracarotid amobartbital procedure) remains the “gold standard” when the language and memory lateralization cannot be determined by the noninvasive methods.1 The procedure involves transfemoral catheterization of the carotid artery followed by administration of shortacting anesthetic agent into one of the cerebral hemispheres and assessing the language and memory functions of The authors have no funding or conflicts of interest to disclose.
352 | www.jnsa.com
awake contralateral hemisphere. The procedure is usually carried out with local anesthetic only, as sedation may interfere with memory test results. Performing WADA test in pediatric patients may be challenging and they often require sedation especially during femoral arterial cannulation. Midazolam and propofol are the commonly used sedatives and both have a profound effect on the memory. In addition, due to the nonavailability of amobarbital, propofol is an alternative agent for intracarotid administration for WADA test.1 We report 2 cases of successful use of dexmedetomidine sedation in pediatric patients (6-y-old male and 7-yold female) during selective middle cerebral artery WADA test with intracarotid propofol. Both the children suffered from refractory complex partial seizures localized to right side and resective procedure was planned. Parents stayed with the patients during the entire testing. Intravenous access was established after topical application of EMLA cream. After standard monitoring including 16-channel EEG, both the patients received intravenous dexmedetomidine 1 mg/kg bolus over 10 minutes followed by an infusion at a rate of 0.5 to 0.8 mg/kg/h. Sedation was titrated to OAA/S (Observer’s assessment of alertness/sedation) scale of 2 to 3. After optimal sedation and local anesthetic infiltration, right femoral arterial catheterization was done. Dexmedetomidine infusion was then stopped in the first patient but continued at Copyright
r
the rate of 0.2 mg/kg/h in the second child during the neurophysiological assessment because of her developmental delay. Both patients had a successful language lateralization. To our knowledge this is the first report on the use of dexmedetomidine sedation for pediatric WADA test. Ideal agent for sedation during WADA test should have rapid onset and offset of sedation, with minimal effects on EEG and memory assessment. Propofol sedation has been described for pediatric WADA testing.2 However, propofol-induced amnesia has been described in children which may be a confounding factor in the memory testing.3 Propofol has also been shown to cause EEG spikes in patients with epilepsy.4 Unique properties of dexmedetomidine make it a favorable sedative agent for this patient population. The well-documented beneficial effects of dexmedetomidine are anxiolysis, analgesia, sedation, and sympatholysis, and it is not associated with respiratory depressive effect. Dexmedetomidine sedation is routinely used in the pediatric patients undergoing continuous EEG in epilepsy monitoring unit, as it does not influence EEG recording in the clinical sedative doses and amnesic effect is shown to be significantly less with dexmedetomidine.3,5 These properties of dexmedetomidine helped us successfully test our pediatric patients for language and memory. However, future welldesigned prospective clinical studies
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
J Neurosurg Anesthesiol
Volume 27, Number 4, October 2015
are needed to investigate the influence of dexmedetomidine sedation on EEG and neuropsychological assessment of pediatric patients during WADA testing. Suparna Bharadwaj, MD, DM Lashmi Venkatraghavan, MD, FRCA, FRCPC Department of Anesthesia, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
REFERENCES 1. Patel A, Wordell C, Szarlej D. Alternatives to Sodium amobarbital in the WADA test. Ann Pharmacother. 2011;45:395–401. 2. Masters LT, Perrine K, Devinsky O, et al. WADA testing in pediatric patients by use of propofol anesthesia. AJNR Am J Neuroradiol. 2000;21:1302–1305. 3. Veselis RA, Reinsel RA, Feshchenko VA, et al. Information loss over time defines the memory defect of propofol: a comparative
response with thiopental and dexmedetomidine. Anesthesiology. 2004;101:831–841. 4. Wang B, Bai Q, Jiao X, et al. Effect of sedative and hypnotic doses of propofol on the EEG activity of patients with or without a history of seizure disorders. J Neurosurg Anesthesiol. 1997;9:335–340. 5. Mason KP, O’Mahony E, Zurakowski D, et al. Effects of dexmedetomidine sedation on the EEG in children. Paediatr Anaesth. 2009;19:1175–1183.
Influence of Strapping of the Hand on Noninvasive Hemoglobin Measurements To JNA Readers: Safe positioning is one of the integral aspects of anesthetic practice. It involves padding and strapping to
Correspondence
protect the patient and prevent extreme positioning of the limbs, head, and neck. We report an interesting observation made while using the Masimo Rad-7 noninvasive hemoglobin (NIHb) measurement (Masimo SET Radical-7, Masimo Corp., CA) that resulted from strapping of the hands. Patient consent was obtained before writing this report. The patient was a 67-year-old man undergoing surgery for foramen magnum meningioma in the prone position. Standard monitoring was applied, including invasive blood pressure monitoring in the left radial artery. An NIHb monitor was attached to the right index finger after the patient was positioned prone with straps and with appropriate padding (Fig. 1E). Two straps were applied to secure the patient, across the arms to the thorax and from the hands to the
FIGURE 1. Change in hemoglobin concentration (solid white box) and perfusion index (dashed white box) before (first row) and after (second row) foam padding removal, as ascertained from the index finger (A), the third finger (B), the fourth finger (C), and the fifth finger (D). Hand of the patient with foam padding (E) and without foam padding (F). C.D.: Initial observation, manuscript preparation; B.V. and B.S.D.: manuscript preparation. The authors have no funding or conflicts of interest to disclose.
Copyright
r
2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.jnsa.com |
353
