Aerosol contamination of operation theater personnel is a great concern during airway manipulation of patients with suspected or proven COVID-19. A plethora of devices such as intubation boxes and barrier devices have been recommended to minimize the spread of aerosols in environment.[1] [2] [3] However, the available devices have some major constraints such as rigid frame, heavy, fixed in design with great restriction in hand mobility, and problem of sterilization.[2] Keeping these points in mind, we have designed an indigenous wire mesh device for barrier protection during airway manipulation along with our senior neurosurgeon. The concept of a stable enclosure, light-weight, cost-effective design along with unrestricted natural movement of the hands and clear visibility was possible with the novel design. The final device was designed and fabricated by the second author.

size that the thoracolumbar interfascial plane (TLIP) block may provide more focused analgesia and may be superior to ESP block in this clinical setting. However, based on the available evidence, at this point in time it is difficult to argue that either of these techniques is consistently superior for analgesia in lumbar spine surgery. In the original description of ESP block, Forero et al3 demonstrated that extensive analgesia of the hemithorax could be obtained by depositing a volume of local anesthetic either superficial or deep to the erector spinae muscle. In the vast majority of subsequent literature, deposition of local anesthetic deep to the erector spinae muscle has become standard. The mechanism of action of the ESP block is still not fully elucidated; possibilities include diffuse cutaneous, paravertebral, or epidural spread of local anesthetic. If local anesthetic deposited superficially to the erector spinae muscle can result in analgesia over most of the hemithorax (even if it is less effective or of shorter duration of action compared with local anesthetic placed deep to the erector spinae), it makes logical sense to assume that it is equally possible that injectate deposited in the TLIP could result in paravertebral or diffuse cutaneous spread. In other words, until subjected to formal investigation using robust scientific methodology, it is not possible to determine which, if either, of TLIP or ESP blocks is superior in lumbar spine (and other) surgery. With the ESP block, there is inconsistency in the pattern of effective blockade between individuals and between studies. For example, some studies have consistently shown anterior cutaneous sparing following ESP block,4 whereas others have reported circumferential sensory loss following bilateral ESP block.5 Possible explanations for these variations include the anatomic complexity of the thoracolumbar fascia, the complex 3-dimensional geometry of the erector spinae muscle group (which changes along its length), volume of injectate administered, and differences in operator technique. I agree with Tseng and Xu that the dorsal rami are the nerves of interest in lumbar spine surgery and that the TLIP block warrants further study. The idea that TLIP block prevents local anesthetic washout is an interesting concept worthy of further investigation. It does seem unlikely that involvement of the ventral ramus would result in delayed ambulation. However, there are anecdotal reports suggesting that lower limb weakness may occur following lumbar ESP block,6 presumably due to spread of local anesthetic to the lumbar plexus. It is also possible that such spread could occur following TLIP block. The one thing we can be certain about is that there are exciting opportunities ahead for investigators who are working to unravel the mechanistic details of these competing truncal fascial plane blocks.

Morbidly obese patients with clinical features of obstructive sleep apnoea can present a myriad of challenges to the anaesthesiologists which must be addressed to minimise the perioperative risks. Initiation of continuous positive airway pressure (CPAP) therapy early in the pre- and post-operative period along with appropriate anaesthetic planning is of paramount importance in such patients. This case report emphasises the usefulness of CPAP therapy, even for a short duration, to minimise morbidity, improve recovery and hasten early discharge from the hospital after major surgery.

Vein of Galen malformations (VOGMs) are rare anomalies of intracranial circulation that constitute 1% of all intracranial vascular malformations. However, they represent 30% of vascular malformations presenting in the paediatric age group.[1] These lesions are characterised by the presence of an aneurysmally dilated midline deep venous structure, fed by abnormal arteriovenous communications. The venous system of the brain is mal-developed many venous anomalies can associate with VOGM. We describe a case of VOGM in which there was hypoplasia of the right internal jugular vein (IJV) leading to failure in the placement of central venous catheter through right IJV.

Tissue ischaemia can be a significant contributor to increased morbidity and mortality. Conventional oxygenation monitoring modalities measure systemic oxygenation, but regional tissue oxygenation is not monitored. Near-infrared spectroscopy (NIRS) is a non-invasive monitor for measuring regional oxygen saturation which provides real-time information. There has been increased interest in the clinical application of NIRS following numerous studies that show improved outcome in various clinical situations especially cardiac surgery. Its use has shown improved neurological outcome and decreased postoperative stay in cardiac surgery. Its usefulness has been investigated in various high risk surgeries such as carotid endarterectomy, thoracic surgeries, paediatric population and has shown promising results. There is however, limited data supporting its role in neurosurgical population. We strongly feel, it might play a key role in future. It has significant advantages over other neuromonitoring modalities, but more technological advances are needed before it can be used more widely into clinical practice.

Jain, Virendra MD, DM; Prakash, Prabhakar S. MD; Dash, Hari H. MD, MNMS Author Information

BACKGROUND:Stellate ganglion block improves cerebral perfusion by decreasing the cerebral vascular tone. Its effects on cerebral vasospasm to relieve neurological deficits have not been evaluated. This prospective observational study was carried out to evaluate the effect of stellate ganglion block on cerebral hemodynamics in patients with symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage. MATERIALS AND METHODS:Fifteen patients of either sex, aged 18-75 years, who underwent surgical clipping of aneurysm and developed refractory cerebral vasospasm were included. Stellate ganglion block was performed using 10 ml of bupivacaine 0.5% on the side with maximum cerebral blood flow velocity. Neurological status, cerebral blood flow velocity and pulsatility index were assessed before and 10 minutes, 30 minutes, 2 hours, 6 hours, 12 hours and 24 hours after stellate ganglion block. RESULTS:Improved Glasgow coma score was observed 30 minutes after stellate ganglion block. Neurological deficits reduced in 11 patients. Ipsilateral middle cerebral artery mean flow velocity decreased from 133.66 cm/sec before stellate ganglion block to 110.53 cm/sec at 6 hours (P<0.001) and 121.62 cm/sec at 24 hours (P<0.001) after stellate ganglion block. There was a decrease in ipsilateral anterior cerebral artery mean flow velocity after stellate ganglion block (P<0.001), which persisted for 12 hours. A decline in flow velocities was observed in contralateral middle cerebral artery (P=0.008) and anterior cerebral artery (P=0.041) for 12 hours. CONCLUSION:This study suggests stellate ganglion block to be an effective modality of treatment for refractory cerebral vasospasm after aneurysmal subarachnoid hemorrhage.

Postoperative nausea and vomiting (PONV) are frequent and distressing complications after neurosurgical procedures. We evaluated the efficacy of ondansetron and granisetron to prevent PONV after supratentorial craniotomy. In a randomized double-blind, placebo controlled trial, 90 adult American Society of Anesthesiologists I, II patients were included in the Study. A standard anesthesia technique was followed. Patients were divided into 3 groups to receive either placebo (saline), ondansetron 4 mg, or granisetron ling intravenously at the time of dural closure. After extubation, episodes of nausea and vomiting were noted for 24 hours postoperatively. Statistical analysis was performed using chi(2) test and 1-way analysis of variance. Demographic data, duration of surgery, intraoperative fluids and analgesic requirement, and postoperative pain (Visual analog scale) scores were comparable in all 3 groups. It was observed that the incidence of vomiting ill 24 hours, severe emetic episodes, and requirement of rescue antiemetics were less in ondansetron and granisetron groups as compared with placebo (P < 0.001). Both the study drugs had comparable effect oil vomiting. However, the incidence of nausea was comparable in all 3 groups (P = 0.46). A favorable influence oil the patient satisfaction scores, and number needed to prevent emesis was seen in the 2 drug groups. No significant correlation was found between neurosurgical factors (presence of midline shift, mass effect, pathologic diagnosis of tumor, site Of tumor) and the Occurrence of PONV. We conclude that ondansetron 4 mg and granisetron 1 mg are comparably effective at preventing emesis after supratentorial craniotomy. However, neither drugs prevented nausea effectively.

Editor, Pneumocephalus, or air within the intracranial cavity, is a common occurrence after the cranial surgery [1]. Tension pneumocephalus in the posterior fossa compressing brain stem is previously reported in the sitting [2] or prone position [3]. To the best of our knowledge, it has not been reported in the supine position. We report a case of brain stem tension pneumocephalus after craniotomy for chronic subdural haematoma (SDH) evacuation performed in supine position. Increase in the intracranial pressure due to pneumocephalus leads to postoperative respiratory distress requiring mechanical ventilation. A 54-year-old, 70-kg man admitted with bilateral chronic SDH was scheduled for left craniotomy and haematoma evacuation, followed by burr hole evacuation of haematoma on the right side under general anaesthesia. All preoperative investigations including pulmonary function tests were within normal limits. After informed consent, routine monitoring was instituted, and anaesthesia was induced. Anaesthesia was maintained with 60% air in oxygen and propofol infusion with intermittent doses of fentanyl and vecuronium. Arterial blood gas tension was normal (pH 7.43, paO2 104.2 mmHg, paCO2 38 mmHg) following intubation. After the frontal craniotomy and haematoma evacuation on the left side, the head was turned to the right for burr hole and haematoma evacuation. During the burr hole evacuation, the head end of the table was tilted about 45° above heart level and then backwards to facilitate evacuation of haematoma. The table was tilted two more times within the next 10 min again at the surgeon's request. Total duration of surgery was 90 min. The intraoperative period was uneventful. At the end of surgery, neuromuscular block was reversed with neostigmine and glycopyrrolate. The trachea was extubated, and the patient was fully awake and following commands. Head lift and handgrip were adequate. Thereafter, the patient was shifted to the ICU. Within 10 min of shifting to the ICU, the patient became restless and irritable, and respiration became irregular and shallow. At that time, pulse was 100 beats min−1, blood pressure 140/86 mmHg, respiratory rate 30 breaths min−1 and SpO2 100%. Auscultation of the chest was unremarkable. Arterial blood gas tension showed pH 7.23, paO2 260.6 mmHg and paCO2 67.8 mmHg. In view of the high paCO2, the respiration was supported by bag and mask. However, even after 5 min, the patient's clinical condition did not improve. He was drowsy and responding only to painful stimulus. It was then decided to initiate mechanical ventilation. The trachea was intubated after giving propofol 100 mg intravenously (i.v.) and rocuronium 70 mg i.v. An urgent computed tomography (CT) of the head was done that revealed air around the brain stem (Fig. 1). The patient was sedated with propofol infusion and ventilated overnight. The following morning, a repeat CT was done that showed that the air around the brain stem had resolved. Neurological response was assessed after stopping sedation. He was conscious following verbal commands and moving all four limbs. The patient was thereafter weaned off the ventilator and extubated. He was discharged from hospital on the third postoperative day with intact neurological status.Fig. 1Tension pneumocephalus is not a rare complication of neurosurgical procedures. Tension pneumocephalus may present as deterioration in the level of consciousness, with or without focal signs, restlessness, generalized convulsions or even cardiac arrest [4]. Posterior fossa tension pneumocephalus has been reported previously after surgery performed in sitting [2], prone [3] and even lateral position [5]. In our case, posterior fossa tension pneumocephalus occurred in supine position. The probable mechanism causing air collection near the brain stem could have been as follows – initially, a craniotomy for left-sided haematoma evacuation was carried out. Inspite of all precautions (isotonic saline instillation before dura closure, keeping drainage site at the lowest point of head) being taken, air may have still collected in the left frontal region. The head was thereafter turned to the left for the burr hole evacuation of the haematoma on the right side. The table was tilted thrice upwards and downwards to facilitate the haematoma evacuation. During the head turning or table tilting, the air may have transgressed from the supratentorial compartment to the infratentorial compartment. When the patient was reversed, a transient rise in the intracranial pressure would have occurred leading to conversion of pneumocephalus to tension pneumocephalus. This tension pneumocephalus could have caused compression on the brain stem leading to irregularity in respiration. The other possibility could have been an inadequate reversal of the neuromuscular blockade. As neuromuscular monitoring was continuously performed until reversal, this possibility of residual neuromuscular paralysis is unlikely. Aspiration of air is the treatment of choice for emergency decompression of tension pneumocephalus. Toung et al. [6] have described four cases of tension pneumocephalus after posterior fossa surgery. In all cases but one, surgical aspiration improved the neurological status. Aspiration was not considered in our case, as the location of the air was near the vital structure in the brain stem. Instead, we initiated mechanical ventilation to tackle the respiratory distress with irritable behaviour (probably due to high paCO2) so as to allow the tension pneumocephalus to resolve spontaneously. The posterior fossa is a narrow space with small volume. Therefore, even a small quantity of collected air, as in our case, could have led to a significant increase in the intracranial pressure. Hence, in the event of respiratory distress following craniotomy, the possibility of tension pneumocephalus in posterior fossa should be considered.

Background and Objectives: To examine the effect of cerebrospinal fluid (CSF) flow during percutaneous retrogasserian glycerol rhizotomy (PRGR) on long term pain relief in patients with trigeminal neuralgia. Methods: Eighty-nine patients with trigeminal neuralgia underwent 102 PRGR procedures. PRGR was conducted under fluoroscopy. After the egress of CSF, anhydrous glycerol (0.3-0.4 cc) was injected in the sitting position. In the absence of CSF flow, 0.25 mL 2% lidocaine was injected to elicit hypesthesia in the affected side. Once hypesthesia was elicited glycerol was injected. Patients were grouped as A (CSF flow present) or B (CSF flow absent), according to the egress of CSF at the time of needle placement. Patients were followed up for the recurrence of pain (average duration of follow up, 62 months). Results: CSF flow was present in 54 patients (60.6%) and absent in 35 patients (39.4%). Thirty patients (56.6%) of group A had excellent pain relief, 18 patients (33.3%) had good pain relief, and 6 patients (11.1%) had no pain relief. However, in the absence of CSF flow, 14 patients (40%) each had excellent and good pain relief, and 7 patients (20%) were treatment failures. The pain relief was comparable between the groups. The median time to recurrence of pain needing further injection was 66 months in group A and 63 months in group B (not significant). Conclusions: Presence of CSF flow during needle placement does not influence the success rate and duration of pain relief following PRGR.

Bispectral index (BIS) is commonly used as an index of depth of anaesthesia and sedation. BIS can provide an additional benefit in detecting a critical neurological event, especially if the change of neurological status is caused by the critical illness itself. We encountered such an incident where the BIS value was decreased in a patient with Guillain Barre Syndrome, possibly due to cerebral hypoperfusion. The present report emphasises that BIS can be used not only as an indicator of cerebral ischaemia, but also as a tool to judge adequacy and efficacy of interventions targeted to restore the same.

Halo fixation is often used to provide stability in patients with unstable cervical spine. These fixation devices pose unique challenges to the anesthesiologists encountered while securing an airway. Management of airway in patients with halo fixation is complicated by the fixed position, limited access to the face, and immobilization of neck. We managed two different patients, one in which halo fixation was done for atlanto-axial dislocation (AAD); and the other, who came with halo fixation and underwent wound debridement under general anesthesia. In the former case, procedure was carried out with laryngeal mask anesthesia and patient breathing spontaneously whereas, in the later case, procedure was performed after securing the airway using awake fiberoptic intubation technique.

To address the practice of various controversial issues in neuroanaesthesia practice in India, a questionnaire survey was conducted during the Annual Conference of Indian Society of Neuroanaesthesiology and Critical Care (ISNACC), held in Hyderabad this year in February 2008. The aim of the survey was to assess the views of the neuroanaesthetists on these issues and its influence in their clinical practice. A simple questionnaire comprising of eight questions was prepared related to the various controversies in neuroanaesthesia. Participants were asked to fill the questionnaire and return before the end of conference. All the questionnaires were distributed in hand and collected personally. The response rate was 66.25% from the nearly 160 delegates. The response was received from nearly an equal number of practitioners, both in the government and corporate sectors. Most of the respondents shared a neutral opinion on the controversies in neuroanaesthesia. New challenges are being faced by anaesthetists with evolution of neurosurgical practice. Various controver-sies have led to more research in this field. Although the awareness exists among Indians, the practice continues at many centres. Multi-centric trials to address such issues may prove beneficial.

To the Editor: Vasospasm remains a significant cause of morbidity and mortality following subarachnoid hemorrhage (SAH). Recently, the role of cervical sympathetic block has been reported to reverse the delayed ischemic neurologic deficit related to vasospasm following SAH (1). We report two cases in which the use of stellate ganglion block (SGB) relieved vasospasm following SAH. Intraarterial digital subtraction angiography confirmed the presence of an anterior communicating artery aneurysm (ACOM) in a 44-yr-old woman diagnosed with Hunt and Hess SAH grade III. Ten days later, following aneurysm clipping, she became drowsy and disoriented and developed right sided weakness with motor power of 1/5 in right upper limb. Her Glasgow Coma Score (GCS) was 11 with motor response of 5. Transcranial doppler (TCD) ultrasound revealed vasospasm on the left side. Intrathecal papaverine 10 mg, a routine treatment in our institution, was given with only minimal improvement in the patient's clinical condition and no change in TCD values. SGB was performed using an anterior paratracheal approach and 10 mL of 0.5% bupivacaine. After 15–20 min, with the onset of SGB all the vessels were again insonated and a significant reduction in the MCA flow velocity was seen (Table 1). At 6 h, the patient showed marked clinical improvement.Table 1: The Mean Flow Velocities (cm/s) in Cerebral Vessels Before and 1 h After Stellate Ganglion Block, and Before and 10 h After Papaverine had been AdministeredOur second patient was a 58-yr-old man diagnosed as Hunt and Hess SAH Grade II. Twelve days after ACOM aneurysm clipping the patient presented with altered sensorium and motor weakness on left side of his body with power of 2/5 in the upper limb. TCD study revealed severe vasospasm of cerebral vessels. SGB was performed and the patient improved both neurologically and clinically and cerebral bloodflow velocity decreased in both the ACA and MCA. Inadvertent administration of intrathecal papaverine 10 mg by the ICU resident had failed to reduce the bloodflow velocity in the cerebral vessels. Repeat SGB had to be given in both patients nearly 24 h after the previous block. The intracerebral vessels constrict in response to cervical sympathetic stimulation and dilate when these fibers are interrupted (2,3). Anatomically, the stellate ganglion contains cell bodies of the inferior cervical ganglion and the first thoracic sympathetic ganglion. Gupta et al. showed that SGB produces a significant decrease in zero flow pressure, which is a surrogate measure of cerebral vascular tone (4). This seems a logical explanation for improvement in our patients with severe vasospasm. Alternatively, since the SGB followed the use of papaverine in both cases, we cannot rule out an interaction between the two treatments. An additional advantage of SGB is that it can be performed as a bed-side procedure unlike cervical sympathetic block described by Treggiari et al. (1) which requires fluoroscopy. Further trials may be indicated to compare the two techniques in terms of onset of action, efficacy, duration of action, and complications. Hemanshu Prabhakar, MD Virendra Jain, MD Girija P. Rath, DM Parmod K. Bithal, MD Hari H. Dash, MD Department of Neuroanaesthesiology All India Institute of Medical Sciences New Delhi, India [email protected]

In anaesthetic practice, exposure to a hazardous substance should be eliminated or controlled where practicable. Over the past few years, the use of nitrous oxide has become debatable. To assess the current anaesthetic practice in India on the use of nitrous oxide, a total of 400 questionnaires constituted by 15 questions on three topics-use of nitrous oxide, medical air and TIVA(total intravenous anaesthesia)-were distributed.Anaesthesiologists were selected randomly and requested to fill up the questionnaire.Of the 400 questionnaires, 40 questionnaires were discarded due to incomplete answer, leaving a total of 360 valid returned questionnaires, a 90% response rate. 27.22% respondents stated that the use of nitrous oxide had decreased .When medical air was available, 66.67% felt that they would use it frequently. A total of 214 (59.44%) stated that they used total intravenous anaesthesia occasionally.The results showed that although anaesthesiologists had reduced their use of nitrous oxide, this was due to medical considerations rather than concerns over health and pollution issues arising from the use of nitrous oxide.