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We revisit the well-known Gilbert–Varshamov (GV) bound for constrained systems. In 1991, Kolesnik and Krachkovsky showed that the GV bound can be determined via the solution of an optimization problem. Later, in 1992, Marcus and Roth modified the optimization problem and improved the GV bound in many instances. In this work, we provide explicit numerical procedures to solve these two optimization problems and, hence, compute the bounds. We then show that the procedures can be further simplified when we plot the respective curves. In the case where the graph presentation comprises a single state, we provide explicit formulas for both bounds.

Background and Aims: There are two approaches for ultrasound (US)-guided vessel cannulation: the short axis (SA) approach and the long axis (LA) approach. However, it remains to be seen which approach is better. Therefore, we performed the present updated systematic review and meta-analysis to assess the effectiveness and safety of US-guided vascular cannulation between the SA and LA techniques. Methods: We performed a comprehensive electronic database search in PubMed, Embase, Cochrane Library and Web of Science for the relevant studies from inception to June 2022. Randomised controlled trials comparing the SA approach and the LA approach for US-guided vascular access were incorporated in this updated meta-analysis. The first-attempt success rate was the primary outcome. The secondary outcomes were the overall success rate, cannulation time, number of attempts and the incidence of complications. The statistical analysis was conducted using RevMan software (version 5.4; the Nordic Cochrane Centre, the Cochrane Collaboration, Copenhagen, Denmark). The Cochrane risk of bias tool was used to evaluate each study's potential risk for bias. Results: In total, 16 studies consisting of 1885 participants were incorporated in this updated meta-analysis. No statistically significant difference was found between the SA and LA vascular access techniques for first-pass success rate (risk ratio = 1.07, 95% confidence interval: 0.94–1.22). The overall cannulation success rate, complication rate, average cannulation time and average number of attempts were not significantly different between the SA and LA groups. Conclusion: This updated meta-analysis demonstrated that the SA and LA approaches of US-guided vessel cannulation are similar regarding first-pass success, overall cannulation success rate, total complication rate, cannulation time and the number of attempts.

The SARS-CoV-2 infection spread rapidly throughout the world and appears to involve in both humoral and cell-mediated immunity. SARS-CoV-2 is attached to host cells via binding to the viral spike (S) proteins and its cellular receptors angiotensin-converting enzyme 2 (ACE2). Consequently, the S protein is primed with serine proteases TMPRSS2 and TMPRSS4, which facilitate the fusion of viral and cellular membranes result in the entry of viral RNA into the host cell. Vaccines are urgently required to combat the coronavirus disease 2019 (COVID-19) outbreak and aid in the recovery to pre-pandemic levels of normality. The long-term protective immunity is provided by the vaccine antigen (or pathogen)-specific immune effectors and the activation of immune memory cells that can be efficiently and rapidly reactivated upon pathogen exposure. Research efforts aimed towards the design and development of vaccines for SARS-CoV-2 are increasing. Numerous coronavirus disease 2019 (COVID-19) vaccines have passed late-stage clinical investigations with promising outcomes. This review focuses on the present state and future prospects of COVID-19 vaccines research and development, with a particular emphasis on immunological mechanisms of various COVID-19vaccines such as adenoviral vector-based vaccines, mRNA vaccines, and DNA vaccines that elicits immunological responses against SARS-CoV-2 infections in humans.

Hiccups are usually self-limiting and benign but can be distressing when they become persistent or intractable and produce significant morbidity. In the intubated patients in neurocritical care, persistent hiccups may cause respiratory alkalosis and are also associated with an increased incidence of ventilator-associated pneumonia. Several pharmacological and nonpharmacological strategies have been devised for the treatment of persistent and intractable hiccups. The evidence to support or declare any intervention as harmful is scarce. In this review, we have presented the pathophysiology and workup, and a stepwise management protocol for intractable hiccups.

Background and Aims: Posterior vessel wall puncture (PVWP) is a common complication of ultrasound (US) guided central venous cannulation. We evaluated and compared the frequency of PWVP of internal jugular vein using short axis (SA) and long axis (LA) approach of US-guided needle cannulation. As a secondary objective incidence of carotid puncture was assessed. Material and Methods: Prospective, single-blinded, cross over, observational study at Urban Level I Neuroanesthesiology and Critical Care Department. Residents receiving standard education on ultrasound-guided central venous cannulation were asked to place an US-guided catheter using either short axis or long axis approach on a human torso mannequin. During the procedure, the path of the needle was carefully observed by the investigator for any PVWP and carotid puncture without interference with the placement procedure. The confidence level of the resident for the intraluminal placement of the needle tip was measured on a 10-point Likert scale. Results: Forty residents participated in the study. The incidence of PVWP in SA and LA group was 40% and 17.5% respectively and was statistically significant (p = 0.026). There was no incidence of carotid artery puncture in either of the group. The mean confidence of intraluminal placement of needle was significantly higher in the LA group (8.32) as compared to the SA group (5.95). Conclusion: Lower incidence of PVWP was seen in LA as compared to the SA approach during US-guided IJV cannulation in phantom in residents having previous experience of CVC (central venous cannulation) in landmark technique only. Participants were more confident about intraluminal needle placement in the LA group compared to the SA group.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2) has rapidly spread across the world including India. Management of patients complicated with neurological illness requiring neurocritical care is challenging during this time. Patients with neurological disease may develop COVID-19 infection or there could be independent neurological manifestations of COVID-19. Critically ill neurological patients are more vulnerable to contracting SARS-CoV-2 infection. Also, neurological patients with comorbidities and multisystem involvement are at increased risk of adverse outcomes. Though SARS-CoV-2 predominantly affects the pulmonary system, it can complicate the assessment and management of neurological patients. With increasing COVID-19 numbers, the hospitalizations of both non-COVID and COVID-19 neurological patients will bring significant strain on the hospital and neurocritical care facilities. Streamlining work pattern, understanding the pathophysiology of COVID-19 and its impact on neurological function, establishing general and specific neurocritical care management strategies, ensuring protection and well-being of health care providers, and implementing effective infection control policies are key elements of efficient neurocritical care management during this pandemic. This joint position statement and advisory on the practice of neurocritical care during the COVID-19 pandemic by the Neurocritical Care Society of India and the Indian Society of Neuroanaesthesiology and Critical Care has been developed to guide clinicians providing care to the critically ill neurological patients in the neurocritical care unit during the current pandemic. As the situation from this novel disease is rapidly evolving, readers must constantly update themselves with newly emerging evidence to provide the best possible care to the critically ill neurological patients.

Fever is probably the most frequent symptom observed in neurointensive care by healthcare providers. It is seen in almost 70% of neurocritically ill patients. Fever of central origin was first described in the journal Brain by Erickson in 1939. A significant number of patients develop this fever due to a noninfectious cause, but are often treated as having an infectious fever. Unjustified use of antibiotics adds to the increased cost of treatment and the emergence of resistant strains, contributing to additional morbidity. Since fever has a detrimental impact on the recovery of the acutely injured brain and contributes to an increased stay in the neurointensive care unit (NICU), timely and accurate diagnosis of the cause of fever in the NICU is imperative. Here, we try to understand the underlying mechanism, risk factors, clinical characteristics, diagnosis and management options of the central fever. We also make an attempt to differentiate two noninfectious causes of fever in the NICU: paroxysmal sympathetic hyperactivity and central fever.

Multimodal neuromonitoring (NM) is the concept of integrating various tools and data to understand brain physiology and guide therapeutic interventions to prevent secondary brain injury. There exists a range of invasive/noninvasive and global/regional monitors of cerebral hemodynamics, oxygenation, metabolism, and electrophysiology that can be used to guide treatment decisions after neurological insult. No single monitoring modality is ideal for all patients. Simultaneous assessment of cerebral hemodynamics, oxygenation, and metabolism allows individualized patient care. The ability to analyze these advanced data for real-time clinical care, however, remains intuitive and primitive. Advanced informatics is promising and may provide us a supportive tool to interpret physiological events and guide pathophysiological-based therapeutic decisions. Available literature is not robust regarding multimodality NM and favorable patient outcome. This narrative review is undertaken to know the status and recent advancement of multimodal NM in neurocritical care.

Objective: The detailed epidemiological and molecular characterization of an outbreak of Burkholderia cepacia at a neurotrauma intensive care unit of a level 1 trauma centre is described. The stringent infection control interventions taken to successfully curb this outbreak are emphasized. Methods: The clinical and microbiological data for those patients who had more than one blood culture that grew B. cepacia were reviewed. Bacterial identification and antimicrobial susceptibility testing was done using automated Vitek 2 systems. Prospective surveillance, environmental sampling, and multilocus sequence typing (MLST) were performed for extensive source tracking. Intensive infection control measures were taken to further control the hospital spread. Results: Out of a total 48 patients with B. cepacia bacteraemia, 15 (31%) had central line-associated blood stream infections. Two hundred and thirty-one environmental samples were collected and screened, and only two water samples grew B. cepacia with similar phenotypic characteristics. The clinical strains characterized by MLST typing were clonal. However, isolates from the water represented a novel strain type (ST-1289). Intensive terminal cleaning, disinfection of the water supply, and the augmentation of infection control activities were done to curb the outbreak. A subsequent reduction in bacteraemia cases was observed. Conclusion: Early diagnosis and appropriate therapy, along with the rigorous implementation of essential hospital infection control practices is required for successful containment of this pathogen and to curb such an outbreak. Keywords: Burkholderia cepacia, Outbreak, Neurotrauma unit, MLST typing, Novel ST type

Patients with permanent pacemaker posted for cervical spine instrumentation pose special challenges for modern-day anesthesiologist since the field of surgery is in proximity to the pacing apparatus. The important considerations in this regard are pacemaker dependency, prior reprogramming to asynchronous mode, perioperative interference with pacemaker function due to electrolyte, acid-base disturbances, and electromagnetic interference leading to pacemaker failure and hemodynamic compromise. We report successful anesthetic management of a patient of postlaminectomy kyphosis with compressive myelopathy with permanent pacemaker in situ who underwent C5–C6 corpectomy and instrumentation under general anesthesia.

Glanzmann thrombasthenia is a rare inherited coagulation disorder, manifesting itself in early childhood as bleeding episodes. The patients with this disease may present with uncontrollable bleeding following trauma. We report a patient of Glanzmann syndrome with head injury, who presented to us following fall from stairs. Platelet transfusion is the mainstay of treatment in emergency situations. As patients generally have a history of platelet transfusion they may be refractory to the same. Leuko reduced or human leukocyte antigen matched platelets should be used. Recombinant factor VIIa can be used to control bleeding in refractory cases and in patients with antibodies against platelets. Anti-fibrinolytics can also be used as adjuvants. There is need of advanced perioperative coagulation screening spot tests in emergency trauma settings as routine coagulation tests may not be able to pick up the abnormality. Thromboelastography/thromboelastometry can be a great tool for perioperative management of such coagulation disorders.

Radioimaging is the gold standard for confirmation of the position of central venous catheter as well as its related complications. Use of ultrasound has been proven in guiding central venous cannulations, and it can also be used in detecting related complications. We report a case of a 2 year old child with hydrothorax causing desaturation due to malpositioned central venous catheter diagnosed by ultrasound in the delay for getting a radiograph.

Mechanical ventilation significantly affects cerebral oxygenation and cerebral blood flow through changes in arterial carbon dioxide levels. Neurosurgical patients might require mechanical ventilation for correction and maintenance of changes in the pulmonary system that occur either due to neurosurgical pathology or following surgery during the acute phase. This review discusses the basics of mechanical ventilation relevant to the neurosurgeon in the day-to-day management of neurosurgical patient requiring artificial support of the respiration.

Purpose: General anesthesia causes inhibition of thermoregulatory mechanisms. Propofol has been reported to cause more temperature fall, but in case of deliberate mild hypothermia, both sevoflurane and propofol were comparable. Thermoregulation is found to be disturbed in cases of pituitary tumors. We aimed to investigate which of the two agents, sevoflurane or propofol, results in better preservation of thermoregulation in patients undergoing transsphenoidal excision of pituitary tumors. Methods: Twenty-six patients scheduled to undergo transsphenoidal removal of pituitary adenomas were randomly allocated to receive propofol or sevoflurane anesthesia. Baseline esophageal temperature was noted. Times for temperature to fall by 1°C or 35°C and to return to baseline were also comparable ( P>0.05). After that warmer was started at 43°C and time to rise to baseline was noted. Duration of surgery, total blood loss, and total fluid intake were also noted. If any, side effects such as delayed arousal and recovery from muscle relaxant were noted. Results: The demographics of the patients were comparable. Duration of surgery and total blood loss were comparable in the two groups. The time for temperature to fall by 1°C or 35°C and time to return to baseline was also comparable ( P>0.05). No side effects related to body temperature were noted. Conclusion: Both propofol and sevoflurane show similar effects in maintaining thermal homeostasis in patients undergoing transsphenoidal pituitary surgery.

The placement of central venous catheter using Seldinger′s technique, remains a commonly performed procedure with its own risks and benefits. Various complications have been reported with the use of guide wire as well as catheter. We report a unique problem during subclavian vein cannulation due to guidewire malposition which led to its kinking and difficult retrieval requiring removal in fluoroscopy suit. The probable mechanism of guide wire entrapment and possible bedside management of similar problems is described.

Aspiration of foreign bodies is common in a pediatric age group but adults can also be at risk. We describe management of two adult trauma victims with aspirated tooth. In the first case, foreign body went missing for sometime by intensive care physician and detected by radiologist while it was obvious in the second case. Both the patients were managed with the help of rigid bronchoscopy. Tooth should be removed as soon as possible or it may result in complete airway obstruction or lung collapse.

Apert syndrome is an autosomal dominant disease characterized by craniosynostosis, midface hypoplasia and syndactyly. In general, patients present in early childhood for craniofacial reconstruction surgery. Anesthetic implications include difficult airway, airway hyper-reactivity; however, possibility of raised intracranial pressure especially when operating for craniosynostosis and associated congenital heart disease should not be ignored. Most of the cases described in literature talk of management of syndactyly. We describe the successful anesthetic management of a patient of Aperts syndrome with craniosynostosis posted for bicornual strip craniotomy and fronto-orbital advancement in a 5-year-old child.

Neurogenic pulmonary edema (NPE) is a well-known entity, occurs after acute severe insult to the central nervous system. It has been described in relation to different clinical scenario. However, NPE has rarely been mentioned after endovascular coiling of intracranial aneurysms. Here, we report the clinical course of a patient who developed NPE after aneurysmal rupture during endovascular surgery. There was significant cardiovascular instability possibly from stimulation of hypothalamus adjacent to the site of aneurysm. This case highlights the predisposition of minimally invasive procedures like endovascular coiling to life-threatening complications such as NPE.

During one lung ventilation (OLV) hypoxemia may occur due to ventilation-perfusion mismatch. It can be prevented with application of ventilation strategy that prevents atelectasis while minimally impairing perfusion of the dependant lung. Here, two cases are reported who required OLV and in whom hypoxemia could be prevented with the application of continuous positive airway pressure to the deflated or non-dependant lung, using an indigenous technique. We suggest use of this technique which is easy to be employed during the intraoperative period.