Besdata Video Laryngeal Mask (BD-VLM)- a New Vision-Incorporated 3rd Generation Video Laryngeal Mask Airway : Dear editor.

Since the recent editorial 2, we were approached to evaluate another video laryngeal mask airway - the Besdata Video Laryngeal Mask (BD-VLM) TM, which has a different design concept, specifications and characteristics (Figure 1) compared to the other two.

Features of new vision-incorporated third-generation video laryngeal mask airways.

Numerous studies have shown that blindly inserted supraglottic airway devices (SADs) are sub-optimally placed in 50 to 80% of all cases. Placement under direct vision has been recommended. We describe the very first two new SADs of the third generation that incorporate a videoscope with flexible tip. Both devices are made up of two interlocking components-the SAD and a videoscope. The 3rd generation, direct vision SADs allow vision-guided insertion, corrective manoeuvres, if needed, and correct placement in the hypopharynx and possess additional features which permit insertion of a gastric tube and endotracheal intubation should the need arise. This article describes the two new devices' physical characteristics, features, rationale for use, advantages and limitations in comparison to existing devices. Each of the two new devices-the Video Laryngeal Mask (VLMTM, UE Medical®) and the SafeLM® Video Laryngeal Mask System (SafeLMTM VLMS, Magill Medical Technology®) consist of two parts: (a) a disposable 2nd generation SAD with a silicone cuff and an anatomically curved tube; and (b) a reusable patient-isolated videoscope and monitoring screen, with the flexible scope located into a specially-designed, blind-end channel terminating in the bowl of the SAD, preventing the videoscope from contacting patient body fluids in the SAD bowl. Third generation placement-under-direct-vision supraglottic airway devices possess several theoretical safety and ease of use advantages which now need to be validated in clinical use.

Association of Obstructive Sleep Apnea With Difficult Intubation: Prospective Multicenter Observational Cohort Study.

BACKGROUND: Obstructive sleep apnea (OSA) has been found to be associated with difficult airway, although there is a paucity of prospective studies investigating thresholds of OSA severity with difficult airway outcomes. The aim of this study was to examine the association between OSA and difficult intubation or difficult mask ventilation. We also explored the utility of the Snoring, Tiredness, Observed apnea, high blood Pressure, Body mass index, Age, Neck circumference, and Gender (STOP-Bang) score for difficult airway prediction. METHODS: The Postoperative Vascular Complications in Unrecognized Obstructive Sleep Apnea (POSA) trial was an international prospective cohort study of surgical patients 45 years or older with one or more cardiac risk factor presenting for noncardiac surgery, with planned secondary analyses of difficult airway outcomes. Multivariable logistic regression analyses tested associations between OSA severity and predictors of difficult airway with difficult intubation or difficult mask ventilation. Overall, 869 patients without prior diagnosis of OSA were screened for OSA risk with the STOP-Bang tool, underwent preoperative sleep study, and had routine perioperative care, including general anesthesia with tracheal intubation. The primary outcome analyzed was difficult intubation, and the secondary outcome was difficult mask ventilation. RESULTS: Based on the sleep studies, 287 (33%), 324 (37%), 169 (20%), and 89 (10%) of the 869 patients had no, mild, moderate, and severe OSA, respectively. One hundred and seventy-two (20%) had a STOP-Bang score of 0-2 (low risk), 483 (55%) had a STOP-Bang score of 3-4 (intermediate risk), and 214 (25%) had a STOP-Bang score 5-8 (high risk). The incidence of difficult intubation was 6.7% (58 of 869), and difficult mask ventilation was 3.7% (32 of 869). Multivariable logistic regression demonstrated that moderate OSA (odds ratio [OR] = 3.26 [95% confidence interval {CI}, 1.37-8.38], adjusted P = .010) and severe OSA (OR = 4.05 [95% CI, 1.51-11.36], adjusted P = .006) but not mild OSA were independently associated with difficult intubation compared to patients without OSA. Relative to scores of 0-2, STOP-Bang scores of 3-4 and 5-8 were associated with increased odds of difficult intubation (OR = 3.01 [95% CI, 1.13-10.40, adjusted P = .046] and 4.38 [95% CI, 1.46-16.36, adjusted P = .014]), respectively. OSA was not associated with difficult mask ventilation, and only increasing neck circumference was found to be associated (adjusted P = .002). CONCLUSIONS: Moderate and severe OSA were associated with difficult intubation, and increasing neck circumference was associated with difficult mask ventilation. A higher STOP-Bang score of 3 or more may be associated with difficult intubation versus STOP-Bang score of 0-2. Anesthesiologists should be vigilant for difficult intubation when managing patients suspected or diagnosed with OSA.

Time to consider supraglottic airway device oropharyngeal leak pressure measurement more objectively.

Oropharyngeal leak pressure (OLP) is considered a measure of successful placement, adequate performance and is a useful comparator between supraglottic airway devices (SADs). OLP measurement is based on the premise that the SAD is sited properly in the hypopharynx after blind placements, but the evidence suggests otherwise. Several limitations and controversies surround OLP. This editorial addresses the uses and pitfalls of OLP, the rationale for and methods of ascertaining OLP, the pros and cons of OLP measurement and newer modalities to improve its accuracy.

Choosing the best supraglottic airway for ophthalmic general anaesthesia: a manikin study.

General anaesthesia is sometimes favoured over regional anaesthesia in ophthalmic surgery. The use of supraglottic airway (SGA) or laryngeal mask airway (LMA) as the primary airway device is increasing due to numerous advantages over tracheal intubation. Compared with 1st generation SGAs, 2nd generation SGAs have an added benefit of isolating the airway from the alimentary tract. However, the vertical profile of SGAs may encroach into the surgical field and hence interfere with surgery. We investigated the vertical projections of 1st generation SGAs (LMA Classic, Ambu AuraFlex) and commonly used 2nd generation SGAs in our institution (LMA ProSeal, LMA Supreme, LMA Protector, Ambu AuraGain and I-gel) in a manikin model. Each device was connected to a corrugated catheter mount or angled connector following insertion as per usual clinical practice in our institutions. Vertical projections of all devices were measured from the chin using a centimetre ruler. Securing of airway device to the chin with an adhesive tape was possible for the LMA Classic and Ambu AuraFlex with straight corrugated connector, whereas the stiffer 2nd generations SGAs required the addition of an angled connector or straight corrugated tubing to direct the airway tube caudally, away from the surgical field. The LMA ProSeal had the lowest vertical projection amongst the 2nd generation SGAs and may be the suitable choice for ophthalmic surgery. We also describe a novel technique of utilising a 1st generation SGA with placement of an orogastric tube, although with some reservations. This study has several limitations and transferability of our findings into clinical practice is questionable as the use of a manikin may not fully imitate the real condition of the patient. Our study is the first study comparing vertical projected height of different SGAs in manikin, but future studies should investigate the use of SGA in the clinical setting during ophthalmic surgery.

Measuring endotracheal tube intracuff pressure: no room for complacency.

Tracheal intubation constitutes a routine part in the care of critically ill and anaesthetised patients. Prolonged use of endotracheal with inflated cuff is one of the major multifactorial causes of complications. Both under-inflation and over-inflation of cuff are associated with complications. Despite known problems, regular measurement of cuff pressure is not routine, and it is performed on an ad hoc basis.

Comparative study of silicone membrane simulator and animal eye models for sub-Tenon's block.

To compare and assess silicone membrane-based sub-Tenon's block (STB) simulator and animal eye model (goat's eye) for practicing STB in terms of anatomical similarity and feel of texture of eye layers. The study included 34 participants (26 learners and 8 consultants) from tertiary ophthalmic centres. The participants were divided into groups A and B. Group A performed STB on the goat's eyes before using the silicone membrane simulator. Group B performed STB on the simulator and further proceeded to the goat's eye. Participants had to rate the anatomical similarity and feel of the texture for the simulator model on a scale of 0-10 and share their preference between the two models. In group A, the scores given to the simulator model and the feel of texture of layers were 8.05 ± 0.88 and 7.97 ± 1.07, respectively, and the scores given to the animal model and the feel of texture of layers were 8.11 ± 0.97 and 8.21 ± 0.88, respectively. Group B participants scored the simulator model and feel of texture of layers with 8.13 ± 0.95 and 8.25 ± 0.99, respectively. Overall, 89% participants preferred the simulator; the reasons included ease of usage, helpful warning system, absence of biological waste, and facility for repeatable training. The study validated anatomical accuracy, preference, and ability of usage of the STB simulator. For broader usage, further study involving higher number of participants is recommended.

The case for a 3rd generation supraglottic airway device facilitating direct vision placement.

Although 1st and 2nd generation supraglottic airway devices (SADs) have many desirable features, they are nevertheless inserted in a similar 'blind' way as their 1st generation predecessors. Clinicians mostly still rely entirely on subjective indirect assessments to estimate correct placement which supposedly ensures a tight seal. Malpositioning and potential airway compromise occurs in more than half of placements. Vision-guided insertion can improve placement. In this article we propose the development of a 3rd generation supraglottic airway device, equipped with cameras and fiberoptic illumination, to visualise insertion of the device, enable immediate manoeuvres to optimise SAD position, verify whether correct 1st and 2nd seals are achieved and check whether size selected is appropriate. We do not provide technical details of such a '3rd generation' device, but rather present a theoretical analysis of its desirable properties, which are essential to overcome the remaining limitations of current 1st and 2nd generation devices. We also recommend that this further milestone improvement, i.e. ability to place the SAD accurately under direct vision, be eligible for the moniker '3rd generation'. Blind insertion of SADs should become the exception and we anticipate, as in other domains such as central venous cannulation and nerve block insertions, vision-guided placement becoming the gold standard.

A prospective randomized comparison of airway seal using the novel vision-guided insertion of LMA-Supreme® and LMA-Protector®.

The laryngeal mask airways supreme (LMA-Supreme™) and protector (LMA-Protector™) are generally placed blindly, often resulting in a less than optimal position and vision-guided placement has been recommended. This prospective, randomized controlled study compared the efficacy of airway seal by measuring the oropharyngeal leak pressure in 100 surgical patients who underwent a variety of non-thoracic surgery under general anaesthesia, suitable with a supraglottic airway device. Patients were allocated to either the LMA-Supreme (n = 50) or LMA-Protector (n = 50) group. All insertions were performed under vision of a videolaryngoscope using an 'insert-detect-correct-as-you-go' technique with standardized corrective measures. Our primary endpoint, mean oropharyngeal leak pressure, was significantly higher in the LMA-Protector (31.7 ± 2.9 cm H2O) compared to the LMA-Supreme (27.7 ± 3.5 cm H2O) group (mean difference 4.0 cm H2O, 95% confidence interval (CI) 2.7-5.3 cm H2O, p < 0.001) after achieving a near-optimal fibreoptic position in the LMA-Protector (94%) and LMA-Supreme (96%) groups. No statistically significant differences were shown for secondary outcomes of alignment, number of insertion attempts and malpositions, and final anatomical position as scored by fibreoptic evaluation. Corrective manoeuvres were required in virtually all patients to obtain a correct anatomically positioned LMA. Position outcomes of the two devices were similar except for the proportion of procedures with folds in the proximal cuff (90% LMA-Supreme vs. 2% LMA-Protector, p < 0.001), the need for intracuff pressure adjustments (80% LMA-Supreme vs. 48% LMA-Protector, p = 0.001) and size correction (18% LMA-Supreme vs. 4% LMA-Protector, p = 0.025). In conclusion, a higher oropharyngeal leak pressure can be achieved with LMA-Protector compared to LMA-Supreme with optimal anatomical position when insertion is vision-guided.

Choosing anesthesia options for cataract surgery in patients with dementia.

BACKGROUND AND AIMS: Not all patients with dementia are the same, and Global Deterioration Scale (GDS) helps in staging dementia. Ophthalmologists usually prefer general anesthesia (GA) for cataract surgery in patients with dementia. We evaluated the impact of "Choosing Wisely" initiative on anesthesia options for cataract surgery in patients with dementia undergoing cataract surgery. MATERIAL AND METHODS: A retrospective review of electronic perioperative database was performed over a 4-year period of patients with a specific diagnosis of dementia undergoing cataract surgery, after the introduction of the "Choosing Wisely" based on preoperative GDS assessment. Preferred method by the listing ophthalmologist, changes in anesthesia modality based on GDS, and the occurrence of intraoperative events were analyzed. RESULTS: One hundred and thirty-six patients with dementia underwent cataract surgery over a 4-year period. The mean patient age was 78 years, 73.5% female, and 55% ASA physical status III. GA was administered for GDS stage 6-7, and regional anesthesia (RA) for GDS stages 1-5. Surgery was uneventful under RA in 64% of the patients (87 out of 136), and 2% (3 patients) originally deemed suitable for RA were converted to GA. CONCLUSIONS: The authors found a reduced requirement for GA when "Choosing Wisely' initiative was used based on the GDS stage.

A snapshot survey of perceptions of healthcare professionals on ageing surgeons.

OBJECTIVE: The aim of this research was to understand healthcare professionals' perception of the continued practice of ageing surgeons in Singapore. METHODOLOGY: A quantitative method was chosen for this research to determine healthcare professionals' perception of the practice of ageing surgeons. Ethical approval was obtained from the local ethical review board. A cross-sectional method using a population survey was performed among healthcare professionals in two tertiary institutions and the study was confined to stakeholders in practices of ageing surgeons. The population sampled was limited to nurses in the theatre, anaesthetists, surgeons and geriatricians (physicians). An online questionnaire was designed for the survey that took into consideration the various conceptual frameworks of ageing surgeons' practice that was obtained from a literature review. RESULTS: There were 104 respondents of a population of 350 sampled (theatre nurses, anaesthetists, physicians and surgeons) giving a respondent rate of 30%. The mean age of the participants was 39.7; 72% were doctors (surgeons 34%, physicians 20% and anaesthetists 18%) and 28% nurses. Only 35% agreed with the statement that older surgeons face deterioration in cognitive faculties and 29% remained neutral. A similar trend was seen with the perception that older surgeons face a decline in memory. However, 44% agreed with the statement that older surgeons face a decline in visuospatial ability and another 40% agreed that they had a decline in psychomotor skills and reaction time. Fifty per cent agreed with the statement that they face deterioration in physical abilities. Sixty-three per cent did not think that older surgeons face a decline in reasoning and judgement. Forty-eight per cent believed that older surgeons' vast fund of knowledge and experience could compensate for physical and cognitive changes. Only 13% agreed with the statement that older surgeons have higher surgical mortality. Forty-five per cent agreed that the retirement age should be 65 while 22% believed it should be over 65. Forty-four per cent agreed that a regular multidisciplinary, objective and comprehensive evaluation of an older surgeon's physical and cognitive function would help to identify and treat reversible problems which when corrected would aid in restoring the surgeon's function. Seventy-four per cent felt that it was the responsibility of all stakeholders to decide or report on when an ageing surgeon is unsafe to continue practicing. Fifty-five per cent disagreed with a mandatory retirement age for surgeons. CONCLUSIONS: This study showed that, in Singapore, stakeholders agreed there are changes in physical and cognitive abilities of ageing surgeons but they thought that these can be overcome with selective strategies to optimise their role in the workforce. They also disagreed on a mandatory retirement age.

Retinal artery occlusion after ophthalmic surgery under regional anaesthesia: A narrative review.

Two recent cases of central retinal artery occlusion under otherwise uncomplicated sub-Tenon's block that resulted in significant visual loss after cataract surgery prompted us to undertake a literature review of such cases. We identified 97 cases of retinal artery occlusion after ophthalmic surgery under regional anaesthesia that had no immediate signs of block-related complications. These occurred after various intraocular (87%) and extraocular (13%) operations, across a wide range of ages (19-89 years) on patients with (59%) or without (39%) known risk factors. The anaesthetic techniques included 40 retrobulbar blocks, 36 peribulbar blocks, 19 sub-Tenon's blocks, one topical anaesthetic and one unspecified local anaesthetic. Different strengths of lidocaine, bupivacaine, mepivacaine and ropivacaine, either alone or in various combinations, were used. The details of the anaesthetic techniques were often incomplete in the reports, which made comparison and analysis difficult. Only nine cases had their cause (optic nerve sheath injury) identified, while the mechanism of injury was unclear in the remaining patients. Various mechanisms were postulated; however, the cause was likely to be multifactorial due to patient, surgical and anaesthetic risk factors, especially in those with compromised retinal circulation. As there were no definite risk factors identified, no specific recommendations could be made to avoid this devastating outcome. We have provided rationales for some general considerations, which may reduce this risk, and propose anaesthetic options for ophthalmic surgery on the fellow eye if required, based both on our literature review and our personal experience.

International survey of ophthalmic anaesthesia service provision, protection of anaesthesia providers and patients during COVID-19 pandemic: a wake-up call.

AIMS: This international survey was conducted to study the impact of Covid-19 pandemic on the provision and practices of ophthalmic anaesthesia, evaluate the methods employed by parent ophthalmic units for safeguarding their anaesthesia providers and patients during lockdown, and to assess pandemic's effect on anaesthesia providers as individuals. The study was done with the hope that the results will help in protecting patients and safeguarding precious human resource by better management if this pandemic was to continue or there was to be another pandemic. METHODS: An anonymous questionnaire survey was distributed electronically between December 2020-January 2021 to the practicing ophthalmic anaesthesia providers in different parts of the world. RESULTS: The survey identified that apart from reducing elective operating services, the ophthalmic units were ill prepared for the pandemic and the overall management was lacklustre. There was a definite lack of effective peri-operative patient screening, and, streaming processes. Measures for personal protection of staff were not optimal especially during regional/local ophthalmic anaesthesia. Severity of the pandemic, sudden job plan changes, and redeployment to intensive care units/acute covid wards had an adverse psychological impact on the affected staff. CONCLUSION: Ophthalmic anaesthesia services worldwide have had poor attentiveness to the life-threatening menace and reality of Covid-19 pandemic. A review of the institutional practices to address correctible deficiencies is urgently required. Robust, mandatory, elective, timely preventative strategies need to be implemented to protect patients, and, the precious ophthalmic workforce from potential adverse physical and psychological injuries.

Anaesthetic considerations for the surgical management of ocular hypotony in adults.

Ocular hypotony can occur from many causes, including eye trauma, ophthalmic surgery and ophthalmic regional anaesthesia-related complications. Some of these patients require surgical intervention(s) necessitating repeat anaesthesia. While surgical management of these patients is well described in the literature, the anaesthetic management is seldom discussed. The hypotonous eye may also have altered globe anatomy, meaning that the usual ocular proprioceptive feedbacks during regional ophthalmic block may be altered or lost, leading to higher risk of inadvertent globe injury. In an 'open globe' there is a risk of sight-threatening expulsive choroidal haemorrhage as a consequence of ophthalmic block or general anaesthesia. This narrative review describes the physiology of aqueous humour, the risk factors associated with ophthalmic regional anaesthesia-related ocular hypotony, the surgical management, and a special emphasis on anaesthetic management. Traumatic hypotony usually requires urgent surgical repair, whereas iatrogenic hypotony may be less urgent, with many cases scheduled as elective procedures. There is no universal best anaesthetic technique. Topical anaesthesia and regional ophthalmic block, with some technique modifications, are suitable in many mild-to-moderate cases, whilst general anaesthesia may be required for complex and longer procedures, and severely distorted globes.