Topic of the Issue: Original Article A retrospective analysis of perioperative complications during intracranial neuroendoscopic procedures: Our institutional experience

Gyaninder P. Singh, Hemanshu Prabhakar, Parmod K. Bithal, Hari Hara Dash

Department of Neuroanesthesiology, Neurosciences Center, All India Institute of Medical Sciences, New Delhi, India

Abstract

Background: Neuroendoscopic procedures are now being performed more frequently, and with advancement in technology, complications related to the procedure and equipments have also minimized or changed. We report our experience with 223 patients who underwent intracranial neuroendoscopic procedures. Materials and Methods: The rates of various perioperative complications, both surgical and related, during intracranial neuroendoscopic surgeries were studied. Data collected included demographics, patient’s medical history and any associated comorbid conditions, diagnosis, procedure performed, anesthetic management, intraoperative and postoperative complications and outcomes. Results: Of the 223 patients studied, 119 were pediatric (age <14 years) and 104 were adults. Hypothermia (25.1%) and cardiovascular complications (such as 18.8%, 11.3%, 16.1%, and hypotension 16.6%) were the commonly observed complications during intraoperative period both in pediatric and adult patients. Address for correspondence: Dr. Hemanshu Prabhakar, At the end of the procedure, delayed arousal was observed in 17 patients and 19 Department of Neuroanesthesiology, patients required postoperative ventilatory support. Postoperative frequent complications Neurosciences Center, 7th Floor, All included: fever (34.1%), tachycardia (32.7%), nausea and vomiting (18.8%). Potentially India Institute of Medical Sciences, fatal complications such as intraoperative hemorrhage, air embolism, etc. were rare. Most New Delhi - 110 029, India. of the complications were transient and self-limiting. Conclusion: Although endoscopic E-mail: prabhakarhemanshu@ procedures are considered minimally invasive, at times may lead to life-threatening rediffmail.com complications and one should be aware of them. Received : 23-04-2011 Review completed : 07-06-2011 Key words: Anesthesia, cardiovascular complications, intracranial surgery, minimally Accepted : 16-07-2011 invasive, neuroendoscopy, surgical complications

Introduction successfully in for various intracranial and spinal lesions, and this has been possible mainly In recent years, endoscopic techniques have been applied due to improvements in the optics and advances in technology.[1] Due to less invasive nature of endoscopic Access this article online surgeries compared to the traditional neurosurgical Quick Response Code: techniques, the incidence and rate of perioperative Website: [2] www.neurologyindia.com complications are expected to be low. Nevertheless, this procedure is also associated with host of complications: PMID: *** Infection, hemorrhage, subdural hygroma, subdural hematoma, , pneumocephalus and DOI: increased (ICP).[3-5] Complications 10.4103/0028-3886.91368 associated with the use of endoscope and irrigation

874 Neurology India | Nov-Dec 2011 | Vol 59 | Issue 6 Singh, et al.: Complications in neuroendoscopic procedures fluid include: Rise in ICP due to rapid run or inadequate patients were recovered to collect the information on egression of irrigation fluid,[6-8] dilution and electrolyte perioperative events during the hospital stay. Various abnormalities,[9,10] to basilar lying beneath the intraoperative and postoperative events recorded third ventricular floor[4] and injury to structures such as included: tachycardia (sudden increase in the fornix, hypothalamus, or . Few studies by 20% of baseline value), bradycardia (fall in heart in the anesthesia literature have discussed perioperative rate by 20% or more), hypertension and hypotension problems in patients undergoing neuroendoscopic (rise or fall in by more than 20%, surgeries.[2,3-5,11] We report our experience of various respectively), hypothermia (fall in core temperature perioperative complications, both surgical and anesthesia below 35.5°C), electrolyte disturbances (hyponatremia related, in 223 patients who underwent neuroendoscopic or hypernatremia), nausea and vomiting, fever procedures at our institute. (temperature above 99°F), increased ICP (suggested by the signs like nausea and vomiting, bradycardia, Materials and Methods drowsiness or altered sensorium and CT findings), failed endoscopic procedures (either due to severe hemorrhage This is a retrospective review of case records of all or inability to reach the site of lesion requiring open patients who underwent endoscopic neurosurgical craniotomies or other alternative procedure), arrhythmias procedures between January 2006 and August 2009. (like premature ventricular contractions, bigemini Data collected included demographics, patient’s medical and asystole), venous air embolism, hemorrhage, history and any associated comorbid condition, diagnosis delayed awakening, meningitis, hydrocephalus, and procedure performed, anesthetic management, pneumocephalus, subdural hygroma, diabetes insipidus, intraoperative and postoperative complications and fistula, shivering, convulsion, the condition of patient at discharge. This study was anisocoria, respiratory complications (like upper or lower approved by institutional ethical committee. respiratory tract infection, pneumonia, pleural effusion, stridor, wheezing, bronchospasm, laryngospasm, Anesthesia protocol tachypnea, desaturation, reintubation, postoperative A standard management protocol was followed for ), psychiatric complications all patients. Most patients received phenytoin sodium (like hallucinations, delirium, restlessness, agitation, and acetazolamide in the preoperative period which somnolence), paresis of various intracranial nerves and was continued till the day of surgery. In addition, new neurological deficits. The duration of postoperative patients receiving drugs for any comorbid conditions ventilation, ICU stay, hospital stay and condition of also continued to receive them. All patients received patient at discharge were also noted. Data are presented glycopyrrolate or atropine an hour prior to surgery. as mean (SD), median (range), or number (percentage). General anesthesia was induced with fentanyl 2 mcg kg and thiopentone 4-5 mg/kg. Tracheal intubation was facilitated using rocuronium 1 mg/kg. Anesthesia was Results maintained with either isoflurane or sevoflurane in a mixture of nitrous oxide (60%) and oxygen (40%) along A total of 240 patients underwent neuroendoscopic with intermittent boluses of fentanyl and vecuronium surgeries during the study period. Of these, data of or rocuronium. Mechanical ventilation was instituted 17 patients were found to be incomplete and were to maintain the end-tidal carbon dioxide concentration excluded from the final analysis. Of the 223 patients at 35 ± 1 mm of Hg. Invasive blood pressure monitoring included in the study, 143 were males and 80 were was performed to record the hemodynamic changes in females; median age was 13 years (14 days to 69 most patients by cannulating either the dorsalis pedis years), 119 patients were in the pediatric age group or the radial artery. Nasopharyngeal temperature was (<14 years), while 104 were adults. The mean weight monitored in all the patients. Normal saline was used was 34.6 (25.2) kg. The associated comorbidity in as the replacement and maintenance fluid during the children was delayed milestones (21%), while in adults intraoperative period. During endoscopy, Ringer’s hypertension was the most common comorbidity solution warmed to 37°C was used for rinsing. At the (8.7%). Other associated comorbidities were: Diabetes end of the surgery, anesthesia was discontinued and mellitus, tuberculosis, asthma, meningomyelocele, neuromuscular blockade reversed with neostigmine encephalocele, convulsions, cranial nerve palsies, atrio- and glycopyrrolate. All patients, whether tracheally septal defect, tracheoesophageal fistula, stridor, history extubated or requiring postoperative ventilation, were of preterm birth, pneumonia, and neonatal sepsis. The shifted to neurosurgical intensive care for supportive average duration of anesthesia and surgery was 147.3 care and further management. (48.9) min and 86.9 (42.6) min, respectively. All patients had received general anesthesia with the Data collection agents, either isoflurane (n = 102) or sevoflurane Intraoperative and postoperative records of the (n = 121), in oxygen (40%) and nitrous oxide (60%)

Neurology India | Nov-Dec 2011 | Vol 59 | Issue 6 875 Singh, et al.: Complications in neuroendoscopic procedures mixture. Various indications and surgeries performed blood. He was discharged on postoperative day 24 with in pediatric age group and adults are listed in Table 1. a Glasgow Coma Score of 12. Different intraoperative and postoperative complications observed are tabulated in Tables 2 and 3, respectively. Discussion The average ICU stay was 1 (1-20) day and the average hospital stay was 4 (2-24) days. Of the 223 patients, The real incidence of complications for neuroendoscopic 19 patients (16 children and 3 adults) could not be procedures is difficult to estimate because not all extubated and required postoperative ventilation. Eight complications are reported[12,13] and there is a lack of these patients had poor respiratory efforts, while 11 of clear definition of what should be considered a patients were drowsy and did not follow simple verbal complication. [12] The reported complication rates for commands. Delayed arousal was observed in 17 patients neuroendoscopic surgeries varied from 6 to 20%.[5,12] of whom 4 were hypothermic. Intraoperatively, hypothermia was the common One patient developed decreased vision in the immediate finding in our study. Causes of hypothermia include postoperative period, but the vision improved to normal low environment temperature of the operation theater, on the second postoperative day. We did not have any inadequate warming measures used for the patient mortality, and all but one patient were discharged with after induction of anesthesia or wetting of drapes with no fresh neurological deficits. One patient who had egression of irrigation fluid. Hypothermia can also multiple complications in the postoperative period: result if too large a quantity of irrigation fluid at room hydrocephalus, intracranial bleed, seizures, fever, temperature is used.[14] In our patients, hypothermia tachycardia, hypertension, and vomiting, and required was observed in spite of using warming measures and ventriculo-peritoneal shunt for drainage of CSF and Table 3: Postoperative complications observed in patients undergoing neuroendoscopic procedures (n = 223) Table 1: Various indications and different neuroendoscopic procedures performed (n = 223) Complications Pediatrics Adults Total Indications Pediatrics Adults Total (n = 119) (%) (n = 104) (%) n (%) (n = 119) (%) (n = 104) (%) n (%) Cardiovascular Hydrocephalus 68 (57.1) 11 (10.6) 79 (35.4) Tachycardia 55 (46.2) 18 (17.3) 73 (32.7) Cysts 28 (23.5) 50 (48.1) 78 (34.9) Bradycardia 6 (5) 2 (1.9) 8 (3.6) Tumors 12 (10.1) 23 (22.1) 35 (15.6) Hypotension 5 (4.2) 3 (2.9) 8 (3.6) Neurocysticercosis 11 (9.2) 19 (18.3) 30 (13.4) Hypertension 3 (2.5) 3 (2.9) 6 (2.7) SAH with — 1 (0.9) 1 (0.4) Respiratory hydrocephalus complications Surgical procedures Stridor 2 (1.7) — 2 (0.9) Ventriculostomy 73 (61.3) 20 (19.2) 93 (41.7) Wheeze 1 (0.8) — 1 (0.4) Cystectomy 15 (12.6) 53 (50.9) 68 (30.5) Tachypnea 1 (0.8) — 1 (0.4) Fenestration 19 (15.9) 8 (7.7) 27 (12.1) Electrolyte imbalance Biopsy 8 (6.7) 13 (12.5) 21 (9.4) Hypernatremia — 1 (0.9) 1 (0.4) Hyponatremia — 1 (0.9) 1 (0.4) Tumorectomy 4 (3.4) 10 (9.6) 14 (6.3) Diabetes insipidus — 1 (0.9) 1 (0.4) n, Total number of patients; SAH - Neurosurgical Hydrocephalus 6 (0.5) 2 (1.9) 8 (3.6) Table 2: Intraoperative complications noted in patients hemorrhage 1 (0.8) 4 (3.8) 5 (2.2) undergoing neuroendoscopic procedures (n = 223) Pneumocephalus 2 (1.7) 3 (2.9) 5 (2.2) Repeat surgery 4 (3.4) 1 (0.9) 5 (2.2) Complications Pediatrics Adults Total n (%) Subdural hygroma 3 (2.5) — 3 (1.3) (n = 119) (%) (n = 104) (%) CSF fistula 2 (1.7) 1 (0.9) 3 (1.3) Cardiovascular Increased ICP 1 (0.8) — 1 (0.4) Tachycardia 26 (21.8) 16 (15.4) 42 (18.8) Neurological Hypotension 24 (20.2) 13 (12.5) 37 (16.6) Convulsions 4 (3.4) 1 (0.9) 5 (2.2) Hypertension 19 (15.9) 17 (16.3) 36 (16.1) Delirium — 3 (2.9) 3 (1.3) Bradycardia 25 (11.2) 10 (9.6) 25 (11.3) Meningitis 2 (0.7) 1 (0.9) 3 (1.3) PVCs — 3 (2.9) 3 (1.3) Paresis — 2 (1.9) 2 (0.9) Bigemini — 2 (1.9) 2 (0.9) Neurological deficits — 1 (0.9) 1 (0.4) Surgical Miscellaneous Hemorrhage 7 (5.9) 5 (4.8) 12 (5.4) Fever 53 (44.5) 23 (22.1) 76 (34.1) Open craniotomy 2 (1.7) 2 (1.9) 4 (1.8) Nausea and vomiting 16 (13.4) 26 (25) 42 (18.8) Rupture cyst — 1(0.9) 1 (0.4) Delayed arousal 13 (10.9) 4 (3.8) 17 (7.6) Miscellaneous Shivering 2 (1.7) 1 (0.9) 3 (1.3) Hypothermia 39 (32.8) 17 (16.3) 56 (25.1) Restlessness — 1 (0.9) 1 (0.4) Air embolism — 1 (0.9) 1 (0.4) n, Total number of patients; CSF - Cerebrospinal fluid; ICP - Intracranial n, Total number of patients; PVCs - Premature ventricular contractions pressure

876 Neurology India | Nov-Dec 2011 | Vol 59 | Issue 6 Singh, et al.: Complications in neuroendoscopic procedures pre-warmed fluid (at 37°C) for irrigation. The frequency in any of our patients, arrhythmias like premature of various cardiovascular changes found in our series ventricular contractions and bigemini were observed; was similar to the observations made in other series.[2,15] probably all these reflect the increase in ventricular In our study, tachycardia was the commonest finding, pressure and/or stimulation of hypothalamic nuclei. with nearly half of the patients having associated hypertension, a finding similar to what has been observed Another potentially fatal complication is the air embolism, by Ganjoo et al.[11] On the contrary, El-Dawlatly et al.[16] either during craniotomy or while withdrawing the observed bradycardia to be the commonest arrhythmia endoscope, and it accounted for 4% in the series by in their study. These hemodynamic changes probably Fabregas et al.[2] We had air embolism in one patient reflect the change in the ICPs which occur with the while doing a burr hole which was detected immediately use of irrigation fluid to improve visibility.[2,8,15,17- 19] and informed to the surgeon who flooded the field with Inadvertent stimulation or injury of the posterior saline. There was tachycardia and hypertension lasting hypothalamus (which modulates the cardiac regulatory for 2-3 min and sustained fall in EtCO2 which gradually function of the brain stem via descending autonomic returned to normal over 90 sec and the further course of pathways) or of the third cranial nerve, both of which the procedure was uneventful. During the event, nitrous lie in close proximity to the floor of third ventricle, can oxide was discontinued and 100% oxygen delivered. also produce significant hemodynamic responses.[20] Bradycardia along with hypertension noted in some Delayed arousal was noted in 17 (7.6%) patients. Large of our patients (described as Cushing ) is the amount of irrigation fluid used during the procedure, clear sign of raised intracranial pressure. Prabhakar which alters the composition of CSF, or the injury to et al.[21] also demonstrated hemodynamic changes the brain structure during surgical manipulation or the and increase in ICP with concurrent fall in cerebral sustained high pressure levels may be the reasons for pressures during Valsalva maneuver in this complication.[2] There was associated hypothermia patients undergoing neuroendoscopic procedures. in four of these patients. Incidence of delayed arousal Anandh et al.[22] also found a significant slowing of the as high as 15% has been reported by Fabregas et al.[2] heart rate during the fenestration of the floor of the and they attributed it some degree of neurological third ventricle. Similarly, El-Dawlatly et al.[19] reported impairment. Most of our patients were extubated at an incidence of 41% of bradycardia in pediatric patients the end of procedure and those who could not be undergoing endoscopic third ventriculostomy (ETV). In extubated were mostly children. These patients either another study by Kalmar et al.,[17] of the 17 patients who did not have adequate respiratory efforts or they were underwent neuroendoscopic procedures, almost every not alert enough (delayed awakening) to follow simple one had hypertension and tachycardia and commands. This may be related to prolonged action (in those patients in whom cerebral perfusion pressure of muscle relaxants or sedatives used (especially in dropped below 15 mmHg), further emphasizing that children) as many a times the procedure ends abruptly, simultaneous onset of hypertension and tachycardia is a causing difficult titration of anesthetics. better and early indicator of impaired cerebral perfusion. Fever was the most common postoperative event in our Massive intraoperative bleeding in the ventricular study and is probably the result of aseptic irritation of system due to damage to the ependymal vessels or the the ependyma or manipulation of the hypothalamus.[24] basilar artery lying beneath the floor of the third ventricle Because of the differences in chemistry between the has been reported by different authors.[17] It is a major irrigation fluid and CSF, toxic reactions have been complication that may necessitate urgent craniotomy reported which manifest as fever, headache, chemical to prevent any catastrophe. In this series, intraoperative meningitis and increased CSF cell count.[14] Irrigation with bleeding was observed in 12 patients, and in 7 of them, normal saline has been reported to cause inflammatory it was associated with various hemodynamic changes. neurological complications including high-grade fever In three patients, the procedure had to be abandoned and headache.[25] In our study, the irrigation fluid used and open craniotomy had to be performed. In another was Ringer lactate, and in most of our patients, fever patient, endoscopy was converted to open craniotomy was transient and resolved with cold sponging or by due to inability to assess the site of lesion. antipyretics.

Handler et al.[23] have implicated the rapid and forceful Transient change in the ionic composition of CSF irrigation to be the cause of cardiac arrest either due to the by the irrigation fluid may cause stimulation of direct distortion of hypothalamic nuclei or secondary to respiratory centers located in the brain stem and this the increase in intraventricular pressure by irrigation fluid has been suggested as the possible cause for respiratory and recommended regulating the speed of irrigation to complications such as hyperventilation.[2] Enya et al. [26] less than 10 ml/min. Though we did not witness asystole described two infants who developed respiratory

Neurology India | Nov-Dec 2011 | Vol 59 | Issue 6 877 Singh, et al.: Complications in neuroendoscopic procedures arrest after endoscopic surgery for hydrocephalus and pressure inside the neuroendoscope correlate to intracranial pressure suggested postanesthetic monitoring of young changes during neuroendoscopic procedures. Anesthesiology 2004;101: A298. infants who undergo ventriculoscopic surgery. One of 9. Derbent A, Ersahin Y, Yurtseven T, Turhan T. Hemodynamic and our patients had tachypnea during the postoperative electrolyte changes in patients undergoing neuroendoscopic procedures. period with no obvious explainable cause. One patient Childs Nerv Syst 2006;22:253-7. had bilateral wheeze and two patients developed stridor 10. Salvador L, Valero R, Carrero E, Caral L, Fernández S, Marín JL, et al. Cerebrospinal fluid composition modifications after neuroendoscopic postoperatively. procedures. Minim Invasive Neurosurg 2007;50:51-5. 11. Ganjoo P, Sethi S, Tandon MS, Singh D, Pandey BC. Perioperative Injury to brain structures or cranial nerves in the adjacent complications of intraventricular neuroendoscopy: A seven year region may result in various postoperative complications. experience. Turk Neurosurg 2010;20:33-8. 12. Hellwig D, Grotenhuis JA, Tirakotai W, Riegel T, Schulte DM, Diabetes insipidus and electrolyte imbalance may result Bauer BL, et al. Endoscopic third ventriculostomy for obstructive [5] from the damage to hypothalamus, and various nerve hydrocephalus. Neurosurg Rev 2005;28:1-34. palsies may result from injury to the cranial nerves or their 13. Buxton N, Punt J. Cerebral after neuroendoscopic third nuclei. Postoperative electrolyte imbalance is most often ventriculostomy: Case report. Neurosurgery 2001;46:999-1001. [16] 14. Ramani R. Minimally invasive neurosurgery: Anesthetic implications. with no clinical significance. However, permanent Seminars in Anesthesia. Perioper Med Pain 2003;22:43-9. diabetes insipidus following third ventriculostomy 15. Ganjoo P, Sethi S, Tandon MS, Chawla R, Singh D. Incidence and has been documented.[27] Other rare complications pattern of intraoperative hemodynamic response to endoscopic third associated with this procedure in our series included: ventriculostomy. Neurol India 2009;57:162-5. 16. El-Dawlatly A, Elgamal E, Murshid W, Watidy S, Jamjoom Z, Alshaer A. Pneumocephalus, subdural hygroma, postoperative Anesthesia for third ventriculostomy: a report of 128 cases. Middle East hydrocephalus, restlessness and confusion. Seizures J Anesthesiol 2008;19:847-57. can be a complication of this procedure;[11,28] five of our 17. Kalmar AF, Van Aken J, Caemaert J, Mortier EP, Struys MM. patients had seizures during the postoperative period. Value of cushing reflex as a warning sign for brain during neuroendoscopy. Br J Anaesth 2005;94:791-9. Postoperative seizures may be the result of either 18. Aken JV, Struys M, Verplancke T, de Baerdemaeker L, Caemaert J, Pneumocephalus, intraventricular bleed or electrolyte Mortier E. Cardiovascular changes during endoscopic third imbalance.[1,11,20] We had no mortality, and the morbidity ventriculostomy. Minim Invasive Neurosurg 2003;46:198-201. at discharge was also very low (0.44%). 19. El-Dawlatly AA, Murshid WR, Elshimy A, Magboul MA, Samarkandi A, Takrouri MS. The incidence of bradycardia during endoscopic third ventriculostomy. Anesth Analg 2000;91:1142-4. The retrospective nature of our study has its limitation. 20. Baykan N, Isbir O, Gercek A, Dagcmar A, Ozek MM. Ten years of We did not monitor ICP in our patients, so the reasons experience with pediatric neuroendoscopic third ventriculostomy. provided for hemodynamic changes secondary to change J Neurosurg Anesthesiol 2005;17:33-7. in intracranial pressures can be considered hypothetical. 21. Prabhakar H, Bithal PK, Suri A, Rath GP, Dash HH. Intracranial pressure changes during valsalva maneuver, in patients undergoing a Long-term outcome of our patients is also not known as neuroendoscopic procedure. Minim Invasive Neurosurg 2007;50:98-101. it was beyond the aim of our study. 22. Anandh B, Madhusudan Reddy KR, Mohanty A, Umamaheswara Rao GS, Chandramouli BA. Intraoperative bradycardia and References postoperative hyperkalemia in patients undergoing endoscopic third ventriculostomy. Minim Invasive Neurosurg 2002;45:154-7. 23. Handler MH, Abott R, Lee M. A near-fatal complication of endoscopic 1. Ambesh SP, Kumar R. Neuroendoscopic procedures: Anesthetic third ventriculostomy: case report. Neurosurgery 1994;35:525-7. considerations for a growing trend-A review. J Neurosurg Anesthesiol 24. Sainte-Rose C, Chumas P. Endoscopic third ventriculostomy. Tech 2000;12:262-70. Neurosurg 1996;1:176-84. 2. Fabregas N, Lopez A, Valero R, Carrero E, Caral L, Ferrer E. Anesthetic 25. Oka K, Yamamto M, Nonaka T, Tomonaga M. The significance of management of surgical neuroendoscopies: Usefulness of monitoring artificial cerebrospinal fluid as perfusate and endoneurosurgery. the pressure inside the neuroendoscope. J Neurosurg Anesthesiol Neurosurgery 1996;38:733-6. 2000;12:21-8. 26. Enya S, Masuda Y, Terui K. Respiratory arrest after ventriculoscopic 3. Ersahin Y, Arslan D. Complications of endoscopic third ventriculostomy. surgery in infants: two case-reports. Masui 1997;46:416-20. Child’s Nerv Syst 2008;24:943-8. 27. Di Roio C, Mottolese C, Cayrell V, Berlier P, Artru F. Ventriculostomy 4. Schroeder HW, Oertel J, Gaab MR. Incidence of complications in of the third ventricle and diabetes insipidus. Ann Fr Anesth Reanim neuroendoscopic surgery. Childs Nerv Syst 2004;20:878-83. 1999;18:776-8. 5. Teo C, Rahman S, Boop FA, Cherny B. Complications of endoscopic 28. Vaicys C, Fried A. Transient hyponatriemia complicated by seizures neurosurgery. Childs Nerv Syst 1996;12:248-53. after endoscopic third ventriculostomy. Minim Invasive Neurosurg 6. Fabregas N, Valero R, Carrero E, Tercero J, Caral L, Zavala E, et al. 2000;43:190-1. Episodic high irrigation pressure during surgical neuroendoscopy may cause intermittent intracranial circulatory insufficiency. J Neurosurg How to cite this article: Singh GP, Prabhakar H, Bithal PK, Anesthesiol 2001;13:152-7. Dash HH. A retrospective analysis of perioperative complications 7. Prabhakar H, Rath GP, Bithal PK, Suri A, Dash H. Variations in during intracranial neuroendoscopic procedures: Our institutional cerebral haemodynamics during irrigation phase in neuroendoscopic experience. Neurol India 2011;59:874-8. procedures. Anaesth Intensive Care 2007;35:209-12. 8. Fabregas N, Valero R, Salvador L, Caral L, Ferrer E. Variation of Source of Support: Nill, Conflict of Interest: None declared.

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