J Neurosurg Anesthesiol
Volume 26, Number 3, July 2014
nasotracheal intubation in children with a normal airway, 87.5% to 90% of intubations with the 2 devices required help of Magill forceps. A recent study showed that the modified Magill forceps facilitated nasotracheal intubation with the GSVL in the patients with predicted difficult intubation.9 Thus, the authors should provide the auxiliary maneuvers used to facilitate nasotracheal intubation in their study. We believe that addressing these factors would further clarify the transparency of this study. Fourth, their statement that nasotracheal intubation under general anesthesia can be a safe, effective first choice for airway management of patients with ankylosing spondylitis is inconclusive. It is generally recommended that awake fiberoptic intubation is the safest option, especially in those patients where it is not possible to visualize the larynx with indirect laryngoscopy or those with severe fixed cervical flexion deformities.2 Moreover, there has been no study assessing the difference between nasal and oral intubation in patients with ankylosing spondylitis. Actually, the nasotracheal intubation is mainly reserved for patients with temperomandibular joint problems and limited mouth opening.10 The nasotracheal intubation may be required for surgical access; however, elective spine surgery is often performed in a lateral or prone position, and orotracheal tube and breathing system do not limit surgical access. In addition, nasotracheal intubation is inherently more traumatic than orotracheal intubation because the tracheal tube has to be passed blindly through the narrow nasal cavity.
2. 3.
4.
5.
6.
7.
8.
9.
10.
J Neurosurg Anesthesiol. 2013. DOI: 10.1097/ ANA.0b013e31829a0491. Woodward LJ, Kam PC. Ankylosing spondylitis: recent developments and anaesthetic implications. Anaesthesia. 2009;64:540–548. Xue FS, Liao X, Li CW, et al. Clinical experience of airway management and tracheal intubation under general anesthesia in patients with scar contracture of the neck. Chin Med J. 2008;121:989–997. Cooper RM, Pacey JA, Bishop MJ, et al. Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients. Can J Anaesth. 2005;52:191–198. Kramer DC, Osborn IP. More maneuvers to facilitate tracheal intubation with the GlideScopes. Can J Anaesth. 2006;53: 737. Apfelbaum JL, Hagberg CA, Caplan RA, et al. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2013;118: 251–270. Lai HY, Chen IH, Chen A, et al. The use of the GlideScope for tracheal intubation in patients with ankylosing spondylitis. Br J Anaesth. 2006;97:419–422. Kim HJ, Kim JT, Kim HS, et al. A comparison of GlideScopes videolaryngoscopy and direct laryngoscopy for nasotracheal intubation in children. Paediatr Anaesth. 2011;21:417–421. Staar S, Biesler I, Mu¨ller D, et al. Nasotracheal intubation with three indirect laryngoscopes assisted by standard or modified Magill forceps. Anaesthesia. 2013; 68:467–471. Hall CE, Shutt LE. Nasotracheal intubation for head and neck surgery. Anaesthesia. 2003;58:249–256.
Correspondence
were performed in all patients, and an additional maneuver with the Magill forceps was routinely used in every patient. Moreover, as we stated in our investigation, laryngoscopy and intubation were performed by an anesthesiologist experienced in the use of these 2 devices (>200 intubations); therefore, inexperience would not be a cause of intubation failure and increased time of intubation.
Xu Lili, MMed* Hu Zhiyong, MMedw *Department of Anesthesiology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China wDepartment of Anesthesiology, The Children’s Hospital, School of Medicine Zhejiang University, Hangzhou, China
Pneumocephalus After Epidural Anesthesia in an Adult who has Undergone Lumbar Laminectomy
REFERENCES
To the Editor: We thank Dr. Dario Caldiroli and his colleagues for their interest in our work and we understand their concern about the need for an additional maneuver with the Magill forceps to address the tube toward the glottis. This instrumentation is essential both with GlideScope and with Macintosh laryngoscopes and makes the 2 devices ultimately comparable. In fact, in our study, nasotracheal intubations using either the GlideScope or the Macintosh laryngoscope
1. Lili X, Zhiyong H, Jianjun S. A comparison of the GlideScope with the Macintosh laryngoscope for nasotracheal intubation in patients with ankylosing spondylitis.
To JNA Readers: A study demonstrated that spinal anesthesia can be performed safely in patients who have undergone lumbar laminectomy.1 However, the safety of epidural anesthesia in patients who have undergone lumbar laminectomy is still controversial. We present a patient who underwent laminectomy and developed symptomatic pneumocephalus with clonic seizures after epidural anesthesia. A 73-year-old woman underwent laminectomy of the L3 and L4 vertebrae for lumbar spondylosis 6 months previously. She underwent a right-sided total knee replacement for osteoarthritis. With the patient in the right decubitus position, a Tuohy epidural needle was inserted into the L3-L4 intervertebral space and the loss-of-resistance with air (LOR-A)
The authors have no funding or conflicts of interest to disclose.
The authors have no funding or conflicts of interest to disclose.
Yi Cheng, MD Rui-Ping Li, MD Fu-Shan Xue, MD Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China
r
2014 Lippincott Williams & Wilkins
Reply
www.jnsa.com |
261
Correspondence
J Neurosurg Anesthesiol
FIGURE 1. Brain computed tomography showing significant pneumocephalus in the subarachnoid spaces of bilateral temporal fossa (arrow) and parafalcine region.
technique was performed. The initial 2 attempts by the midline approach were unsuccessful and some CSF was drained accidentally. The epidural space was identified by the paramedian approach on the third attempt at the L4-L5 intervertebral space. No CSF was drained from the epidural needle on the third attempt. The amount of air utilized by an experienced anesthesiologist was 9 mL. An epidural catheter was advanced 3 to 4 cm, and anesthesia was induced with bupivacaine (Marcaine Spinal 0.5% Heavy) 2.8 mL. About 30 minutes after anesthesia induction, the patient developed bilateral upper limb clonic seizures. Surgery was halted immediately and convulsions terminated 5 minutes after intravenous lorazepam 2 mg was administered. Brain computed tomography (CT) revealed significant pneumocephalus in the subarachnoid space of the bilateral temporal fossa and parafalcine region (Fig. 1). CT of the lumbar spine revealed air in the spinal canal and
262 | www.jnsa.com
posterior paraspinal soft tissue. The amount of air disclosed on the brain and the spine was more than the injected air during the LOR-A procedure, which was estimated to be 15 mL. The patient was treated conservatively with 100% oxygen and a second brain CT did not reveal any residual intracranial air 4 days later. In a large study, 2.2% of patients developed pneumocephalus after undergoing the LOR-A technique during epidural anesthesia.2 The risk of pneumocephalus can be reduced by using saline instead of air to identify the epidural space.3 However, many anesthesiologists still prefer the LORA technique because the column of air within the syringe provides a better sensation of compressibility than saline. Unlike our case, in which the patient had significant pneumocephalus, in most cases of epidural anesthesia– induced pneumocephalus, only small air bubbles in the ventricles, Sylvian fissure, and chiasmatic cisterns were revealed.2 We propose that the large
Volume 26, Number 3, July 2014
air volume in the intracranial space in our patient may have resulted from several factors. First, the lamina and ligamentum flavum were removed in the previous lumbar laminectomy. The absence of ligamentum flavum resistance made it difficult to identify the epidural space, which resulted in multiple attempts with a large volume of air injected into the epidural space. The epidural air may be trapped into the subarachnoid space by a dural breach, which may have developed in the previous 2 attempts. Second, although the subarachnoid space usually continues to have positive pressure, a deep breath, especially against a closed glottis, may cause transient subarachnoid space negative pressure and thus, trapped epidural air in the subarachnoid space.4 Third, pneumocephalus may also be associated with unintentional injection of air into the subarachnoid space during attempted confirmation of the epidural space. Finally, because the amount of air in the intracranial space is greater than the actual amount which anesthesiologist used, we hypothesize the retention of air in the soft tissue of lumbar region after laminectomy is possible. One previous article also demonstrated that gas can exist in the soft tissue after spinal surgery.5 This soft tissue air may have entered the subarachnoid space by dural breach and thus provides a possible explanation for the greater amount of air in the intracranial space relative to what the anesthesiologist injected during LOR-A. In conclusion, we suggest that previous lumbar laminectomy may be a relative contraindication for performing epidural anesthesia, especially when the LOR-A technique is used.
Jen-Chun Wang, MD Shih-Hung Tsai, MD Wen-I Liao, MD Department of Emergency Medicine Tri-Service General Hospital National Defense Medical Center Taipei, Taiwan Republic of China
REFERENCES 1. Berkowitz S, Gold MI. Spinal anesthesia for surgery in patients with previous lumbar laminectomy. Anesth Analg. 1980;59: 881–882. r
2014 Lippincott Williams & Wilkins
J Neurosurg Anesthesiol
Volume 26, Number 3, July 2014
2. Aida S, Taga K, Yamakura T, et al. Headache after attempted epidural block: the role of intrathecal air. Anesthesiology. 1998;88: 76–81. 3. Scott DB. Identification of the epidural space: loss of resistance to air or saline? Reg Anesth. 1997;22:1–2. 4. Kozikowski GP, Cohen SP. Lumbar puncture associated with pneumocephalus: report of a case. Anesth Analg. 2004;98:524–526. 5. Ilkko E, Lahde S, Koivukangas J, et al. Computed tomography after lumbar disc surgery. Acta Radiol. 1988;29:179–182.
Protocol for Vasospasm To the Editor: The following standard protocol of care is applied to all patients in our institution for vasospasm. On admission, oral nimodipine (360 mg/d) is given orally or in the gastric tube if patients remain ventilated. In addition, patients receive fluids: normal saline around at least 2.5 L/d to maintain euvolemia. Mean arterial pressure is kept at least 10% to 15% above the baseline.1 Norepinephrine is the most common vasopressor used to elevate blood pressure. Early detection of cerebral vasospasm is based on repeated neurological examination in the intensive care unit. Routine transcranial Doppler of cerebral arteries is performed at least daily, or more if required.2 If required, computed tomography angiography/perfusion imaging is also performed. Cerebral vasospasm is suspected when patients exhibit neurological alteration or suggestive Doppler changes, either separately or in combination. Patients who developed cerebral vasospasm despite our standard preventive treatment are eligible for continuous intravenous infusion of milrinone. If well tolerated, the dose is progressively incremented from 0.5 mg/kg/min to 1.0 mg/kg/min.3 Patients who show no signs of improvement or develop focal neurological deficit are made to undergo intra-arterial dilatation therapy using
The authors have no conflicts of interest to disclose. r
2014 Lippincott Williams & Wilkins
nimodepine mostly alone or in combination with milrinone in the case of resistant vasospasm.4 Continuous infusion of vasodilators is reserved for those patients in whom the focal deficit improves after intra-arterial dilatation but is not sustained long enough.5 In conclusion, we would like to say that there is a significant amount of evidence in the literature supporting the neuroprotective role of nimodipine in patients with subarachnoid hemorrhage. This is not the case, however, with all other treatment options available for vasospasm. However, newer pharmacological agents, such as milrinone, have a safer profile and may well be of some benefit in maintaining adequate cerebral blood flow. Needless to say, further testing is required for validating these promising but preliminary results. The importance of performing largescale, multi-institutional, randomized clinical trials, along with the usage of unified outcome criteria in these trials, is of paramount importance for establishing general guidelines for vasospasm management. Saurabh Anand, MD Gaurav Goel, MD, DM Vipul Gupta, MD Medanta, The Medicity, Gurgaon, India
REFERENCES 1. Dankbaar JW, Slooter AJ, Rinkel GJ, et al. Effect of different components of triple-H therapy on cerebral perfusion in patients with aneurysmal subarachnoid haemorrhage: a systematic review. Crit Care. 2010; 14:R23. 2. Saqqur M, Zygun D, Demchuk A. Role of transcranial Doppler in neurocritical care. Crit Care Med. 2007;35(suppl):S213–S216. 3. Lannes M, Teitelbaum J, del Pilar Corte´s M, et al. Milrinone and homeostasis to treat cerebral vasospasm associated with subarachnoid hemorrhage: the Montreal Neurological Hospital protocol. Neurocrit Care. 2012;16:354–362. 4. Romero CM, Morales D, Reccius A, et al. Milrinone as a rescue therapy for symptomatic refractory cerebral vasospasm in aneurismal Subarachnoid hemorrhage. Neurocrit Care. 2009;11:165–171. 5. Doukas A, Petridis AK, Barth H, et al. Resistant vasospasm in subarachnoid hemorrhage treated with continuous intraarterial nimodipine infusion. Acta Neurochir Suppl. 2011;112:93–96.
Correspondence
Alternative BIS Montage Positions: Caution Still Warranted To the Editor: We appreciate the thoughtful letter and response from Kim and colleagues regarding our article “An alternative position for the BIS-Vista montage in frontal approach neurosurgical cases.” Their letter brings to light the challenges (and danger) that can be associated with utilizing the BIS-Vista monitor in nonstandard locations, with false elevations noted in utilizing electrodes in a more inferior, mandibular position. As a number of studies, including ours, have begun to examine the BIS monitor in such nonstandard positions, it is important to recognize that not all sites have demonstrated correlation with standard BIS positioning, and that care must be taken when applying the BIS to nonstandard locations.1–3 In such instances, it is even more important to be conscious of the overall clinical picture of the patient, and to not simply treat the patient solely based upon a BIS value. One must consider the anesthetic utilized if the electrodes are placed over significant musculature (ie, the masseter), and examine the BIS and EEG tracings to ensure they appear appropriate and not demonstrating signal interference. However, most importantly, additional studies that focused on alternative positions of the BIS montage in cases where the standard montage cannot be utilized are warranted. Those to date have begun to demonstrate the feasibility of such alternatives; however, the correlation is not perfect. We look forward to seeing the results from the prospective study by Kim and colleagues in hopes of further clarifying appropriate alternative positions for the BIS monitor in neurosurgical cases.
The authors have no funding or conflicts of interest to disclose.
www.jnsa.com |
263
Volume 26, Number 3, July 2014
nasotracheal intubation in children with a normal airway, 87.5% to 90% of intubations with the 2 devices required help of Magill forceps. A recent study showed that the modified Magill forceps facilitated nasotracheal intubation with the GSVL in the patients with predicted difficult intubation.9 Thus, the authors should provide the auxiliary maneuvers used to facilitate nasotracheal intubation in their study. We believe that addressing these factors would further clarify the transparency of this study. Fourth, their statement that nasotracheal intubation under general anesthesia can be a safe, effective first choice for airway management of patients with ankylosing spondylitis is inconclusive. It is generally recommended that awake fiberoptic intubation is the safest option, especially in those patients where it is not possible to visualize the larynx with indirect laryngoscopy or those with severe fixed cervical flexion deformities.2 Moreover, there has been no study assessing the difference between nasal and oral intubation in patients with ankylosing spondylitis. Actually, the nasotracheal intubation is mainly reserved for patients with temperomandibular joint problems and limited mouth opening.10 The nasotracheal intubation may be required for surgical access; however, elective spine surgery is often performed in a lateral or prone position, and orotracheal tube and breathing system do not limit surgical access. In addition, nasotracheal intubation is inherently more traumatic than orotracheal intubation because the tracheal tube has to be passed blindly through the narrow nasal cavity.
2. 3.
4.
5.
6.
7.
8.
9.
10.
J Neurosurg Anesthesiol. 2013. DOI: 10.1097/ ANA.0b013e31829a0491. Woodward LJ, Kam PC. Ankylosing spondylitis: recent developments and anaesthetic implications. Anaesthesia. 2009;64:540–548. Xue FS, Liao X, Li CW, et al. Clinical experience of airway management and tracheal intubation under general anesthesia in patients with scar contracture of the neck. Chin Med J. 2008;121:989–997. Cooper RM, Pacey JA, Bishop MJ, et al. Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients. Can J Anaesth. 2005;52:191–198. Kramer DC, Osborn IP. More maneuvers to facilitate tracheal intubation with the GlideScopes. Can J Anaesth. 2006;53: 737. Apfelbaum JL, Hagberg CA, Caplan RA, et al. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2013;118: 251–270. Lai HY, Chen IH, Chen A, et al. The use of the GlideScope for tracheal intubation in patients with ankylosing spondylitis. Br J Anaesth. 2006;97:419–422. Kim HJ, Kim JT, Kim HS, et al. A comparison of GlideScopes videolaryngoscopy and direct laryngoscopy for nasotracheal intubation in children. Paediatr Anaesth. 2011;21:417–421. Staar S, Biesler I, Mu¨ller D, et al. Nasotracheal intubation with three indirect laryngoscopes assisted by standard or modified Magill forceps. Anaesthesia. 2013; 68:467–471. Hall CE, Shutt LE. Nasotracheal intubation for head and neck surgery. Anaesthesia. 2003;58:249–256.
Correspondence
were performed in all patients, and an additional maneuver with the Magill forceps was routinely used in every patient. Moreover, as we stated in our investigation, laryngoscopy and intubation were performed by an anesthesiologist experienced in the use of these 2 devices (>200 intubations); therefore, inexperience would not be a cause of intubation failure and increased time of intubation.
Xu Lili, MMed* Hu Zhiyong, MMedw *Department of Anesthesiology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China wDepartment of Anesthesiology, The Children’s Hospital, School of Medicine Zhejiang University, Hangzhou, China
Pneumocephalus After Epidural Anesthesia in an Adult who has Undergone Lumbar Laminectomy
REFERENCES
To the Editor: We thank Dr. Dario Caldiroli and his colleagues for their interest in our work and we understand their concern about the need for an additional maneuver with the Magill forceps to address the tube toward the glottis. This instrumentation is essential both with GlideScope and with Macintosh laryngoscopes and makes the 2 devices ultimately comparable. In fact, in our study, nasotracheal intubations using either the GlideScope or the Macintosh laryngoscope
1. Lili X, Zhiyong H, Jianjun S. A comparison of the GlideScope with the Macintosh laryngoscope for nasotracheal intubation in patients with ankylosing spondylitis.
To JNA Readers: A study demonstrated that spinal anesthesia can be performed safely in patients who have undergone lumbar laminectomy.1 However, the safety of epidural anesthesia in patients who have undergone lumbar laminectomy is still controversial. We present a patient who underwent laminectomy and developed symptomatic pneumocephalus with clonic seizures after epidural anesthesia. A 73-year-old woman underwent laminectomy of the L3 and L4 vertebrae for lumbar spondylosis 6 months previously. She underwent a right-sided total knee replacement for osteoarthritis. With the patient in the right decubitus position, a Tuohy epidural needle was inserted into the L3-L4 intervertebral space and the loss-of-resistance with air (LOR-A)
The authors have no funding or conflicts of interest to disclose.
The authors have no funding or conflicts of interest to disclose.
Yi Cheng, MD Rui-Ping Li, MD Fu-Shan Xue, MD Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China
r
2014 Lippincott Williams & Wilkins
Reply
www.jnsa.com |
261
Correspondence
J Neurosurg Anesthesiol
FIGURE 1. Brain computed tomography showing significant pneumocephalus in the subarachnoid spaces of bilateral temporal fossa (arrow) and parafalcine region.
technique was performed. The initial 2 attempts by the midline approach were unsuccessful and some CSF was drained accidentally. The epidural space was identified by the paramedian approach on the third attempt at the L4-L5 intervertebral space. No CSF was drained from the epidural needle on the third attempt. The amount of air utilized by an experienced anesthesiologist was 9 mL. An epidural catheter was advanced 3 to 4 cm, and anesthesia was induced with bupivacaine (Marcaine Spinal 0.5% Heavy) 2.8 mL. About 30 minutes after anesthesia induction, the patient developed bilateral upper limb clonic seizures. Surgery was halted immediately and convulsions terminated 5 minutes after intravenous lorazepam 2 mg was administered. Brain computed tomography (CT) revealed significant pneumocephalus in the subarachnoid space of the bilateral temporal fossa and parafalcine region (Fig. 1). CT of the lumbar spine revealed air in the spinal canal and
262 | www.jnsa.com
posterior paraspinal soft tissue. The amount of air disclosed on the brain and the spine was more than the injected air during the LOR-A procedure, which was estimated to be 15 mL. The patient was treated conservatively with 100% oxygen and a second brain CT did not reveal any residual intracranial air 4 days later. In a large study, 2.2% of patients developed pneumocephalus after undergoing the LOR-A technique during epidural anesthesia.2 The risk of pneumocephalus can be reduced by using saline instead of air to identify the epidural space.3 However, many anesthesiologists still prefer the LORA technique because the column of air within the syringe provides a better sensation of compressibility than saline. Unlike our case, in which the patient had significant pneumocephalus, in most cases of epidural anesthesia– induced pneumocephalus, only small air bubbles in the ventricles, Sylvian fissure, and chiasmatic cisterns were revealed.2 We propose that the large
Volume 26, Number 3, July 2014
air volume in the intracranial space in our patient may have resulted from several factors. First, the lamina and ligamentum flavum were removed in the previous lumbar laminectomy. The absence of ligamentum flavum resistance made it difficult to identify the epidural space, which resulted in multiple attempts with a large volume of air injected into the epidural space. The epidural air may be trapped into the subarachnoid space by a dural breach, which may have developed in the previous 2 attempts. Second, although the subarachnoid space usually continues to have positive pressure, a deep breath, especially against a closed glottis, may cause transient subarachnoid space negative pressure and thus, trapped epidural air in the subarachnoid space.4 Third, pneumocephalus may also be associated with unintentional injection of air into the subarachnoid space during attempted confirmation of the epidural space. Finally, because the amount of air in the intracranial space is greater than the actual amount which anesthesiologist used, we hypothesize the retention of air in the soft tissue of lumbar region after laminectomy is possible. One previous article also demonstrated that gas can exist in the soft tissue after spinal surgery.5 This soft tissue air may have entered the subarachnoid space by dural breach and thus provides a possible explanation for the greater amount of air in the intracranial space relative to what the anesthesiologist injected during LOR-A. In conclusion, we suggest that previous lumbar laminectomy may be a relative contraindication for performing epidural anesthesia, especially when the LOR-A technique is used.
Jen-Chun Wang, MD Shih-Hung Tsai, MD Wen-I Liao, MD Department of Emergency Medicine Tri-Service General Hospital National Defense Medical Center Taipei, Taiwan Republic of China
REFERENCES 1. Berkowitz S, Gold MI. Spinal anesthesia for surgery in patients with previous lumbar laminectomy. Anesth Analg. 1980;59: 881–882. r
2014 Lippincott Williams & Wilkins
J Neurosurg Anesthesiol
Volume 26, Number 3, July 2014
2. Aida S, Taga K, Yamakura T, et al. Headache after attempted epidural block: the role of intrathecal air. Anesthesiology. 1998;88: 76–81. 3. Scott DB. Identification of the epidural space: loss of resistance to air or saline? Reg Anesth. 1997;22:1–2. 4. Kozikowski GP, Cohen SP. Lumbar puncture associated with pneumocephalus: report of a case. Anesth Analg. 2004;98:524–526. 5. Ilkko E, Lahde S, Koivukangas J, et al. Computed tomography after lumbar disc surgery. Acta Radiol. 1988;29:179–182.
Protocol for Vasospasm To the Editor: The following standard protocol of care is applied to all patients in our institution for vasospasm. On admission, oral nimodipine (360 mg/d) is given orally or in the gastric tube if patients remain ventilated. In addition, patients receive fluids: normal saline around at least 2.5 L/d to maintain euvolemia. Mean arterial pressure is kept at least 10% to 15% above the baseline.1 Norepinephrine is the most common vasopressor used to elevate blood pressure. Early detection of cerebral vasospasm is based on repeated neurological examination in the intensive care unit. Routine transcranial Doppler of cerebral arteries is performed at least daily, or more if required.2 If required, computed tomography angiography/perfusion imaging is also performed. Cerebral vasospasm is suspected when patients exhibit neurological alteration or suggestive Doppler changes, either separately or in combination. Patients who developed cerebral vasospasm despite our standard preventive treatment are eligible for continuous intravenous infusion of milrinone. If well tolerated, the dose is progressively incremented from 0.5 mg/kg/min to 1.0 mg/kg/min.3 Patients who show no signs of improvement or develop focal neurological deficit are made to undergo intra-arterial dilatation therapy using
The authors have no conflicts of interest to disclose. r
2014 Lippincott Williams & Wilkins
nimodepine mostly alone or in combination with milrinone in the case of resistant vasospasm.4 Continuous infusion of vasodilators is reserved for those patients in whom the focal deficit improves after intra-arterial dilatation but is not sustained long enough.5 In conclusion, we would like to say that there is a significant amount of evidence in the literature supporting the neuroprotective role of nimodipine in patients with subarachnoid hemorrhage. This is not the case, however, with all other treatment options available for vasospasm. However, newer pharmacological agents, such as milrinone, have a safer profile and may well be of some benefit in maintaining adequate cerebral blood flow. Needless to say, further testing is required for validating these promising but preliminary results. The importance of performing largescale, multi-institutional, randomized clinical trials, along with the usage of unified outcome criteria in these trials, is of paramount importance for establishing general guidelines for vasospasm management. Saurabh Anand, MD Gaurav Goel, MD, DM Vipul Gupta, MD Medanta, The Medicity, Gurgaon, India
REFERENCES 1. Dankbaar JW, Slooter AJ, Rinkel GJ, et al. Effect of different components of triple-H therapy on cerebral perfusion in patients with aneurysmal subarachnoid haemorrhage: a systematic review. Crit Care. 2010; 14:R23. 2. Saqqur M, Zygun D, Demchuk A. Role of transcranial Doppler in neurocritical care. Crit Care Med. 2007;35(suppl):S213–S216. 3. Lannes M, Teitelbaum J, del Pilar Corte´s M, et al. Milrinone and homeostasis to treat cerebral vasospasm associated with subarachnoid hemorrhage: the Montreal Neurological Hospital protocol. Neurocrit Care. 2012;16:354–362. 4. Romero CM, Morales D, Reccius A, et al. Milrinone as a rescue therapy for symptomatic refractory cerebral vasospasm in aneurismal Subarachnoid hemorrhage. Neurocrit Care. 2009;11:165–171. 5. Doukas A, Petridis AK, Barth H, et al. Resistant vasospasm in subarachnoid hemorrhage treated with continuous intraarterial nimodipine infusion. Acta Neurochir Suppl. 2011;112:93–96.
Correspondence
Alternative BIS Montage Positions: Caution Still Warranted To the Editor: We appreciate the thoughtful letter and response from Kim and colleagues regarding our article “An alternative position for the BIS-Vista montage in frontal approach neurosurgical cases.” Their letter brings to light the challenges (and danger) that can be associated with utilizing the BIS-Vista monitor in nonstandard locations, with false elevations noted in utilizing electrodes in a more inferior, mandibular position. As a number of studies, including ours, have begun to examine the BIS monitor in such nonstandard positions, it is important to recognize that not all sites have demonstrated correlation with standard BIS positioning, and that care must be taken when applying the BIS to nonstandard locations.1–3 In such instances, it is even more important to be conscious of the overall clinical picture of the patient, and to not simply treat the patient solely based upon a BIS value. One must consider the anesthetic utilized if the electrodes are placed over significant musculature (ie, the masseter), and examine the BIS and EEG tracings to ensure they appear appropriate and not demonstrating signal interference. However, most importantly, additional studies that focused on alternative positions of the BIS montage in cases where the standard montage cannot be utilized are warranted. Those to date have begun to demonstrate the feasibility of such alternatives; however, the correlation is not perfect. We look forward to seeing the results from the prospective study by Kim and colleagues in hopes of further clarifying appropriate alternative positions for the BIS monitor in neurosurgical cases.
The authors have no funding or conflicts of interest to disclose.
www.jnsa.com |
263
