Lecture: Conversations With an Ophthalmic Anesthetist: Topics We Should All Know

During this live webinar, we will open up a discussion of several topics where both the surgeon and anesthetic provider take responsibility for the well-being of the patient and the successful outcome of the eye surgical procedure. Topics that will be addressed are commonly faced concerns: should patients be fasted, how to manage a patient with dementia, poorly controlled blood pressure or blood sugar, and the recognition and management of rare, but serious, medical problems in the operating room. (Level: Intermediate)

Lecturer: Dr. Manish Raval, Ophthalmologist, Moorfields Eye Hospital, United Kingdom of Great Britain and Northern Ireland


Good afternoon from London. My name is Dr. Manish Raval. Essentially, I believe this is the first time there is a presentation made by an anesthesiologist or an anesthetist. So bear with me so I hopefully bring value to everyone. Whether you’re an anesthetist, a nurse, a provider. Someone that works in the operating environment of eye surgery and hopefully we can get something together between us in terms of a discussion that is relevant from your own perspective. I called this working together for safer eye surgery. I was touched by hunter’s suggestion that I had a special secret I could share but I think we all have knowledge that we can share. I have no conflicts of interest. My experience is a UK trained anesthetist. I trained through the University College of London. Performed a fellowship in Australia. I’ve been a consultant for 20 years and I worked for ten years in the hospital and I’m full time now at Moorfields eye hospital. And I’m with the fellowship of royal anesthetists. I worked with the royal college of surgeons. I worked in Sierra Leone and the bulk of my anesthesiology work is with Orbis. I’m akin to how they teach and propagate safe surgical practice. There are a number of countries where I worked and all of them have taught me more than I learned anywhere else I imagine. Why have I picked the content that I picked. It’s ideas that I recognize as important and it’s a suggest that was suggested to me by Orbis eye surgeons. And one or two have come out by topics proposed by attendees, at least in the early days. If you have given a question or a suggest matter, I may not cover it in this but maybe in the questions and answer. Let’s begin. I think the best way to start is with a bit of inter-action, otherwise, it’s just about me talking. So the first question I want to bring to you is about your opinion on a certain aspect of practice. So most of this presentation is going to be about my opinions and I know that you hold opinions that are strong and dear to what you do and reflect your practice and your knowledge. I would like you to share as much as possible. So let’s have a look at the first question. Do you use the WHO surgical safety checklist. I’d like you to be as honest as you can. Yes, in full. Brief time out and debrief always. You do some part of it regularly. You do some part of it occasionally. You tried to do it and have given up or you simply never heard of it. What’s reassuring about this is most of the people out there have at least participated in surgical safety checklist to some extent. What’s worrying though is a third have never heard of it. Without really spend ago whole lecture upon this, which is very easily done, I would suggest we talk about why it’s beneficial. There’s a good 30 percent of you that probably realizes already and are performing it in its entirety. And I respect and applaud you for that. Let’s share the reasons why we think this is relevant. Andy, I can’t close that slide and move on. That’s it. Thank you very much. So my belief is when this was first introduced, it was an idea that kind of had essentially use anywhere and everywhere in the world which is quite unusual for medical advancements. We are often very much predicted on what investments and resources we can invest. This takes very little. It takes engagement, a recognition of a process and a team working together. There is evidence, proper randomized control trial evidence that suggests that mistakes are reduced by using a system such as this. Any system will reduce mistakes but what this system allows you to do is adopt a system that is globally recognized and as a result you will be supported essentially by the WHO to invest in producing this as a local checklist that you can then execute on a regular basis. The idea being, that right from the outset, the team introduces itself, everybody has a name and an allocated role that is known. As a result, there is better communication. People are likely to talk to each other and as a result are less likely to make mistakes where they try to cover up their lack of knowledge or lack of understanding or their lack of awareness of what is going on. They are more inclined to ask and that helps enormously. The reality is mistakes happen and we need to create methodology to stop that from happening and as a result less problems with death, less problems with morbidity in terms of complications. It also has a useful thing where it positively recognized all members of the team. At the time-out, everybody is involved in recognizing the patient is there for a particular procedure, these particular instruments and the correct side is being done. Such a common area in lateralized surgery such as eye surgery and yet there is no easy way of stopping this. Even the surgical safety checklist had failures in doing this. But it brings you closer to recognizing it’s going to happen. And your colleagues can speak about the patients is a very useful part of this. When you are creating your list structure at the start in the brief, you have a better list management strategy. You’re less likely to keep patients starved or — prioritization and get a better flow for the list. Less stopping and starting. This is endorsed by all the major health providers including Orbis. So it’s essentially feels like a no-brainer that people should try. If you have never heard of this, I’m sure through Orbis you can get more information and start practicing this straight away. That is as much preaching that I can do about that. This is an enormous suggest and I would love to talk more but we want to move on. I have another question for you. This is a specific medical question with a view to you looking at your medical practice in a particular situation. So not uncommonly patients will present for eye surgery either as known hypertensives or as a newly presenting hypertensives. Let’s look at this particular individual. A 67-year-old man with known hypertension presents for elective cataract surgery. Documented history of heart disease, stroke, and diabetes. No documented history, sorry. He has taken his normal morning dose of amlodipine 5 mg one hour previously but the blood pressure is being recorded as part of the preop observation and it gives you the following values. Systolic of 181 and diastolic with 92 and a pulse is regular at 84 beats per minute. Known hypertensive. That’s the only condition he is suffering from and takes one medication. That’s his blood pressure and he is about to have cataract surgery. Do you proceed? Just using the facts that I give a you, yes, you proceed, because there are no concerns. Or yes, but this is not the case for training. Yes, give him something to reduce anxiety first. Like a benzodiazepine and then proceed. Yes, but let’s actively lower blood pressure with whatever medication you’re most comfortable and familiar with and go ahead with the surgery. Or no, patient should be sent away. Should be given instructions to start additional anti-hypertensive medication and monitor the blood pressure and return for surgery after 6 weeks. There is clearly many other alternative pathways but try to pick one of those that is closest to your opinion. Okay. So very interesting again. Because I think I’m going to clash with the global opinion out there which I’m quite pleased about in one respect. It goes to show that you’re essentially being very safe medical practitioners. More than, I think almost two-thirds of you want to differ this to control blood pressure or control blood pressure here and now before the surgery. Let’s discuss that in the next few slides. So blood pressure, it’s a global concern. Up to 80 percent of adults aged over 60 are known to maybe either suffer from blood pressure with requiring medication or being monitored. That’s almost a billion people. We have thresholds that have been defined by virtue of the fact they’re associated with target organ damage. These are numbers, systolic greater than 180 and diastolic greater than 110. Clearly, other factors would also contribute to making a risk greater with lower blood pressure. Diabetes, known heart disease and known stroke. These are the values that we use to guide us as a way of knowing there is likely target organ damage. There is increased risk associated with hypertension. Adverse medical outcomes like cardiovascular patient cans suffer from heart disease and have angina and myocardial infarction during surgery or have a stroke. And these things can complicate the perioptical period. Working in and around the eye, you are concerned there is can be a surgical complication. What’s the background to this. High blood pressure is going to be increased fragility of ocular blood vessels. Sometimes, the side effects of the drugs you treat blood pressure with, alpha blockers, can result in making the surgery more difficult with a floppy iris. Hypertension is associated with more capsular cataract distribution and makes the surgery more challenging. And anybody who has hypertension has associated comorbidities and acute end organ damage. Renal dysfunction, ischemia, heart disease. But, is there any evidence that this is going to cause problems in eye surgery? And this is the important thing. Evidence exists for other types of surgery and we often extrapolate that evidence to eye surgery. But we have to be careful about doing so because clearly those patients are having surgeries where the intervention in itself is much more likely to precipitate blood pressure changes, la liability up and down and have more consequence for the surgery itself. There are several studies over the decades but little or no evidence at all of systemic problems. My most intriguing study was a Dutch case series where they looked at 4,000 patients and decided that adverse scabbing and neuro events were rare. Whatever the blood pressure of the patient at presentation, they went ahead and had surgery and there were no recorded systemic complications. In the UK, a similar case study of 740 cases were done in 2010 and again, resulted in no adverse systemic problems. The problem with some of these studies is treatments have often been given which have not been picked up by researchers. People have their blood pressure treated and — we just don’t know that. But, across all of the studies out there, most of the information comes from those types of surgery which I don’t think are relevant to eye surgery. You have to be careful to interpreted the results from those that should influence involvement in an eye operation. The biggest concern I’m often presented with is when a surgeon says I’m unhappy about the blood pressure, we may risk supra choroidal hemorrhage. A British study looked at all the hemorrhages reported over the course of a year and a half, almost 100 cases and in none of those was blood pressure a significant risk factor in the patient. The only time I found evidence was in combined glaucoma surgery and cataract surgery where there was a delayed risk of supra choroidal hemorrhage with raised blood pressure. A very small issue. What are the practical considerations. I’m suggesting maybe we don’t need to worry about this. We should be aware of the patient’s blood pressure and be considerate of what to do to image them. Is the patient anxious. Have they missed treatment. Often patients omit drug tons day of surgery and that can have a consequence. Have we been generous with drops to dilate the eye. Is the patient in pain. Is the patient cold. But on the day of surgery, a blood pressure recording is a blood pressure recording and that can cause you concern before starting the surgery. What most guidance suggests is look at the measurements made in primary care. I accept that is not always available but these values are much more reliable. The trends of the patient displays over time, over the last few months are more reflective of their normal blood pressure and the slight rise in blood pressure that is associated with anxiety of a surgical event is not relevant. If you are treating blood pressure though, remember that treatment takes time and you do need to wait for that to take place. So it takes 6 to 8 weeks for regression of endothelial and vascular changes. You should treat blood pressure ahead of surgery if there are other factors present. My concern is those interventionists that are talking about a third of the group said they would acutely treat the blood pressure with a medication. It’s hard to know what medication is probably the ideal. Given the fact there is variation across the world in terms of what is available, this is different across different centers. But it can be hazardous, you have to carefully consider the drug you’re going to use in terms of the longevity of action. Are you going to send the patient home with a blood pressure lower than it should be and they have a consequence that is not eye related or do you find yourself treating with agents that have interactions with drugs they’re already on that can cause problems. All of these things make that need to treat blood pressure in the time before surgery more challenging and more problematic than actually just recognizing this blood pressure may not cause a problem. Emphasizing that again. Measurements from primary care are more useful than those taken add at mission. That is why we at Moorfields insist on the blood pressure coming from the GP itself. Where blood pressure is within 20 percent of that baseline, so what the blood pressure measurement in the primary care situation, unless it’s highly severe hypertension, systolics well over 200 and diastolics well over 110. Those are the only situations we postpone and treat the blood pressure with medical guidance. Even if the patient’s baseline is 170/105 or within 20 percent of that, we would be inclined to carry on with surgery. There are so many consequences of surgery. The psychological problems of the patient. The social situation. They may have traveled long distance and financial problems related to that. In our country there are waiting lists that make people very, very stressed if they feel the surgery is not going to be done when their opportunity arises and they’re going to be put at the back of the waiting list again. This is opinion-based as you can see. Although I’ve quoted evidence to you, I’m sure it’s possible to find evidence that counters that. The fact that there is no clear evidence in either direction does leave us in the unknown here. But whatever your unit chooses to do, I think you should have a really coherent and consistent policy. That’s one of the challenges that we face in a large hospital, keeping the consistency and making sure all anesthetists and surgeons work with the same rule book. There is always individual opinion and ultraconservative and less so. We need to bring ourselves together and work with a consistent rule book and that way the patients are treated fairly. Moving on. I’ll give you a break to gather your thoughts and talk about another patient situation. On this occasion, we have a 79-year-old lady, who is frail and presents for cataract surgery suffering from bilateral brunescent cataracts. She shows science of early dementia but is still able to give informed consent for the procedure. She takes regular medication to treat Parkinson’s disease and is well controlled with no resting tremor. In addition, she takes oral medication for type two diabetes and her blood sugar level is 63 millimoles. It’s relatively well controlled. She is able to mobilize and lie flat. She is anxious about the procedure. Her vision has gone down badly in the last 6 months and for that reason you’re considering sedation. You know her surgery is tomorrow and there is very little else to improve the situation here and now but you think sedation might help. Here is another poll. Do we think the instructions we give her is she should have absolutely no oral intake over night. Or do you think she must have nothing to eat and drink overnight except for her normal medication. Or no food or medication for 6 hours preop and no amount of water 2 hours preop. Or do you think she may eat and drink normally and take the normal doses of medication. Or do you think this is not relevant to you. You don’t make this decision and you’re not involved in counseling the patient on their fasting status and you wouldn’t get involved. Share your answers with me. Okay. Very good spread of answers here. The largest portion have gone to essentially say no food or medication 6 hours preop. And no amount of water. This is standard. This is uniform for almost all types of surgery where a patient has a general anesthetic and has been validated by experience but not really evidence. We don’t know as anesthetists what the ideal starvation times are. Things have moved on dramatically and we’re now feeding patients with carbohydrate rich drinks before surgeries to improve outcomes but we’re talking about eye surgery now. I am tending to the eat and drink normally and take all your regular doses of medication. That is my personal opinion on this. I can see that somewhere along the way there are certain criteria that may reflect the approach of a whole unit and it may be the way you work. You share the word, you share the preop assessment unit, you share the delivery of surgical services with a bunch of surgeons and complicating the instructions given to patients for eye surgery opposed to orthopedic surgery or general surgery may cause more difficulty than it’s worth. I see that and I wouldn’t be able to argue again it. But in eye surgery we’re a unique situation. Can I move on then? Why do we create this no by mouth fasting strategy? It’s considered a safety require for general anesthetics and deeper sedation. The idea being when you give drugs that obtund a patient, make a patient very sleepy, you may reduce the reflex activity that protects them from passive or active regurgitation and the ability to stop aspiration pneumonia. And aspiration pneumonia as a complication is one of the worst things that can happen in anesthetics: It causes such profound problems that death is often part of the outcome and it’s avoidable but simple measures to keep patients starved. It’s easy to do. Why shouldn’t we do for all patients. But do we think it’s necessary for local anesthetic techniques alone or with mild conscious sedation. You have to remember compared to other types of surgery, any of those orthopedic general surgical operations, how likely is it that Juan ophthalmic procedure will risk local anesthetic toxicity but shear dosage of the anesthetic in and around the eye or emergency conversion to general anesthetic. Those are the two principle risks that people hold in the back of their mind when they’re committing to an anesthetic technique in other surgical specialties and still insist on the patient being starved. I would argue that the risk of either is almost small to vanishing. For that reason, we don’t tend to starve our patients that may be coming from simple local anesthetic techniques or what we call mild conscious sedation. The idea is the patient still remains awake and cooperative and the patient is still communicative. They are simply given medication to give anxiolysis. A reduction of anxiety. Not to be asleep. Definitely not and that is always emphasized. Why. Why does it matter? There are benefits to not fasting. The better experience may not sound like the most important thing when doing what is very involved surgery and trying to get through as many patients as possible and try to result in as good of an outcome as possible. But if it’s a better experience with patients which it is, there is less fear and anxiety. They have a lower perception to pain as the surgery proceeds and they tend to have no postop nausea and vomiting. And for that, the surgeon benefits. The surgeon is able to get a patient who is going to lie still and follow instructions which is probably the biggest challenge with patients who are fidgeting and causing disturbance during the operation. You’re less likely to need sedation if you haven’t starved the patient. And by not fasting, there is no evidence that there’s a greater risk of any other intraoperative complication in eye surgery. So, there’s a special group of patients. The diabetic patients. If we fast them and they’ve misinterpreted their dosing schedules, hypoglycemic can be presented and that’s much more problematic. Given the normal intake with the normal medication, keeps their blood sugars in a normal range. Much. More so. Elderly patients with dementia who must form a significant part of your workload, the regular schedule of eating and drinking and going through life as they normally would protect them against confusion. So say having a regular intake of calories does that also, too. Most importantly is that emphasis that if you’re eating and drinking on the morning of surgery, you take your regular medication. And less clearly this medication is going to create a risk for the surgery. Whether that is an anticoagulant that you want omitted or a particular anti-hypertensive agent that can cause a profound drop in blood pressure. Those things need to be selected and stopped but otherwise, we have an open understanding of our patients that we expect them to take all of their regular medication. That way, you don’t have that risk of losing disease control which is often going to create a greater risk to the patient than anything during the perioperative period. Clearly, allowing patients to eat and drink normally does sometimes open the flood gates to misinterpretation and bad behavior and you have to be clear that alcohol and illicit drugs are not part of this. That is not going to help you and it’s not going to help them. So further patient preparation. We want to give preop guidance, verbal or written. We want to create a sense of what is going to happen to them. That preparation often allows them toe ask questions that are relevant and know what is expected of them. They know the sequence of events that will happen on the day of surgery. They know the duration of waiting, the intraoperative period and most importantly they know how to behave. We want them to cooperate with us and allow the surgery to happen without difficulty. I always suggest them to wear loose and comfortable clothing. It’s rare in the UK now for the elderly patients that have fought in wars and come in in suits and ties but I feel it flattering they feel this is an important way to present themselves to the surgeon and the team operating on them because they feel it’s respectful but it’s not going to help them be comfortable. I say be comfortable. Loosen your tie. And lay comfortably. The patients need to lay in a flattish position but it doesn’t need to be perfectly flat. I think there are more surgeons in resource poor countries who I’ve seen work more flexibly around more angled patients. Slightly higher head levels than in the UK. It’s a real challenge in the UK for us to deal with patients who have difficulty lying flat because they have breathing problems or some element of cardiac failure or profound reflux or profoundly obese. And these ones have to go to a select group of surgeons who are comfortable working in a semi-recumbent position. This is something you get to learn to do because you’re skilled surgeons and work with a team that will help you. But, remember the patient’s part in this. Emphasizing that what they can do to adopt a position that is going to help you because you need to be able to tell them that the risk of movement. How it can cause problems. But do this in a kind and considerate manner. We don’t want to put all the fear that we can in them. We want them to be calm and cooperative. Now pain is a tricky one. Because they may be pain during the surgery. Whether it’s a topical approach or blocks. As a result, you do need to be able to give them warning this may be part of the process. But, what we often observe and it’s puts a smile on the face of the anesthetist because sometimes the surgeon unintentionally creates pain in the patient. I think the best way to deal with this is just simply say, if you feel pain, let me know. But not necessarily warn of pain at each step. You have to be careful of the words. If you warn the patient they will feel pain, more than likely they will feel pain because of the placebo effect. They have heightened awareness of what they’re going to feel. I don’t want to teach you things you’re well experienced in doing but those are words that I have come to think about when I speak to new surgeons and just get them prepared for the way they talk to their patients. Now, more interaction please. I’m sure not all of you deal with pediatrics but I’m sure a large proportion of you have to because that’s the nature of your practice, both adults and children. You don’t have the niche divisions as elsewhere in the world. This is about a child with an upper respiratory tract infection, sometimes referred to as a URI in the U.S. A nine-year-old girl previously diagnosed with Congenital glaucoma presents for urgent surgical trabeculotomy. She had been managed with medical therapy but has shown acute deterioration. At the time of admission, she had a persistent cough. Her parents explain that over the previous week she was feverish and coughing and not feeling well. Most of the symptoms have slightly improved but the cough still persists. I’m sure you’ve all been faced by something like this in your time. But looking just at the facts I presented to you just now, how would you proceed? Her parents have really expressed concern because they know that general anesthetics is dangerous with a chest infection. Do you proceed with surgery under general anesthesia as soon as possible. Do you proceed after one week treating with antibiotics and physio therapy in between. Do you wait for 6 weeks after the upper respiratory tract infection symptoms have settled and proceed with general anesthetic. Or refer her to a large pediatric tertiary center with the possibility of complications can be managed or proceed under local anesthetic? Okay. Very few going ahead straight away there. They’re recognizing risk and managing risk. That’s what we do in medicine, we manage risk and do it in a way that we know is appropriate. Good split between waiting 6 weeks and another split between sending to the pediatric tertiary center. Very few people say proceeding under local. I think proceeding under local with a 9-year-old is challenging and it takes a skilled set of surgeons and nurses around her to achieve that. It’s possible, but it takes a very high level of skill to do that. I would be challenged by that. Let’s talk about this. What would my answer be? Really difficult. I found that question the hardest of all the ones I posted. I recognize when a surgeon says to me this can be sight saving, it’s absolutely incumbent of me to find a solution. My solution, I would say go ahead with the surgery and manage the symptoms as best I could knowing that I have the recourse of the greatest pediatric hospitals in London: But I also know that you don’t wherever you might be working. That puts me in a very privileged position. I have to admit being safe around a child in more challenging environments is the most important thing: Recognize you may well have to compromise in the surgical intervention as a result. I believe too many children have died as a result of anesthetics going wrong rather than surgery going wrong. That is not something you can ignore. Upper respiratory tract infections, common childhood infections. Most kids get 6 to 8 a year. Sometimes described as a common cold, sneezing, nasal congestion and discharge, sore throat, cough, fever, malaise. Can be very, very vague. They are associated when given a general anesthetic in a situation of one of these being present with perioperative respiratory adverse events. A complication. That is because there is reactivity in the airways which is much more heightened as a result of the inflammation. And patients can suffer from laryngospasm and bronchospasm, profound coughing, persistent coughing, airway obstruction or stridor. Breath holding and hypoxia. In fact, layer ring sew spasm is the most likely cause for respiratory induced cardiac arrest. If you have a patient with some of these features and you have other risk factors present, like the child is being prematurely born or the child has coexisting asthma. Comes from an environment where there is passive smoking. Or there’s a history of snoring in a child, then you should be very, very, very aware that complications can be more problematic. What can you do about it? Elective surgery, you can only cancel unless it’s just minor symptoms and an older child. There is no point taking a risk for a surgery that can be done at any time. Can you use investigations to guide you? They’re not really that useful. Sometimes putting the oxygen probe on the finger can help because it can guide you there is a pneumonia present or they may have depressed saturation and that can be helpful because it’s a major warning sign this may not be the right way forward. If you must go ahead, what can you do. Assure the child is well hydrated. Minimal starvation times as much as possible. Even where a patient is coming from general anesthetic in my center and my practice, we ask the child to stay hydrated up to an hour preop. That is no by mouth to food 6 hours preop but continue with clear fluids, specifically, water up to one hour before. And provide breathing circuits. Nebulized solutions or through a mask can help just as much to soften the secretions and help them clear as much as they can. Of the drugs you can use, bronchodilators help. Perhaps they stop the reactive changes further down the airway. Anticholinergics don’t help. If you are going to do a general anesthetic, some type of laryngeal mask airway is preferred over a tube. You have to be sensible about making the choice. Very small children, you may not feel confident and comfortable this is still a secure enough airway and an endotracheal tube may be the better choice. If you can use a supra glottic airway, it’s less stimulating and less likely to result in problems at induction and emergence. And IV anesthetics perform better than vapors. That’s a privilege that I have. Not all of you have them and I recognize that. what you can do is do a — type of anesthetic. Where if you’re giving a vapor induction, maybe assist with an IV dose at the time when you first perform laryngoscopy to ensure you have control. And on the reverse side, when you’re getting to emergence, use small doses of IV anesthetics as you reduce the vapor content in the child to stop them from becoming reactive to what is essentially an airway irritant and hopefully you can have a nice smooth emergence. Peri anesthetic on that last bit because it’s much more about what anesthetists do. But I wanted to share this for all of the audience. I know I’m getting close to the end but I want to do a couple more. I’m going to make you think about something else in anesthetics that we do here at Moorfields. A 29-year-old woman 33 weeks pregnant presents for a urgent macular detachment surgery. She will be under conventional retinoplexy. She has poorly controlled glaucoma for years. A high miope with an axial length of 29 mm. She is pregnant but we go ahead and give her a general anesthesia or we send her off to a maternity unit where they can give a general anesthetic because they have obstetric care standing by but the surgeon has to move with her. Or do it under local anesthetic. We can give a peribulbar block or a retro bulbar block. Or we can use a sub Tenon block acknowledging that these blocks are not as efficacious or lasting. Or give a topical anesthesia and oral sedation. Share your thoughts. Okay. Well, I’m glad that, well there’s a small portion that thought to do the general anesthetic where they are. They may have obstetric and maternity support on site. But giving general anesthetics for non-obstetric reasons is one of the most fraught things. There are considerations and risks, it’s quite a daring thing to do. Probably better to have it done with maternity services literally standing by and monitoring and tell you all is well. The largest group is for general anesthetic rather than local anesthetic. I argue, I firmly suggest to you these surgeries can well and truly be done under local anesthetic. This is something we proudly do at Moorfields. We consider patients to consider local as a technique. Where there are risks to themselves or an unborn child, we’re positive about the benefits of doing this under local. If you give any child, any unborn child a drug whether it’s anesthetic or otherwise, there is a risk of teratogenicity. In this case it’s late in the pregnancy so much less of a concern. But there are general risks with changes to blood pressure and all kinds of concerns in the way the mother is managing risk of airway and risk of hypoxia. There are risks related to the unborn child that we want to manage. The possibility of pregnancy induced hypertension or glucose intolerance. Those can make managing these patients very difficult. But the bottom line is, there is a very serious risk in the general anesthetic in this group. You need to consider when you get the patient to lie flat, to give a general and then start the surgery. That is often needed. You need to consider uterine displacement and the risk of reflux. If you don’t displace the uterus and potentially block venous return which is the cardiac output which is perfusion to the fetus. If you risk, failing to treat any of these, because there are all these concerns going on in terms of the patient’s eye, it can be problematic. So what I would like you to consider is going back and thinking about the local anesthetic approaches and what makes you hold yourself back. What makes you think a local anesthetic approach may not be correct? Clearly, a sharp needle block has problems. Especially if you recognize that it’s a long eye and the risk increases with that long eye. The potential complications of perforation. You should consider staphlomma present because of the glaucoma. That may be the most common and comfortable technique, maybe you need to engage in a new technique and the sub Tenon is a very good technique. I will reemphasize that in the next case. Let’s see if it influences your choices. You can take the options off for me and I’m going to move to the next question. Thank you. Sorry. I jumped forward. Now, here we go. We’re going to — there’s been a slight change in consideration. With that in mind, let’s pose the last question and I can wrap up. This time a 59-year-old man suffered trauma to the left eye. Presented 72 hours after the injury and the penetrating injury is now infected and showing signs of sepsis. He tachycardic and he has a significant medical history. Had a skin disease for several years and gets shortness of breath and occasional chest pain on very little exertion. He experienced a pulmonary embolus three months earlier and takes Warfarin. His INR is a 2.9. Let’s think about how we can do this. He needs to be done. This is an emergency. Surgery as soon as possible. Know that GA is at risk but get on and do it. Start IV antibiotics. Wait 24 to 48 hours before surgery or immediate surgery under the local anesthetic. Peribulbar or retro bulbar block. Immediate surgery using the sub Tenon block. Or just saying surgery cannot be done safely and he should be treated with IV antibiotics. Okay. So again, there’s a good consideration of safety here and treating with IV antibiotics, the fact that he is septic seems perfectly reasonable. Giving a general anesthetic will be a shaky time for this patient. I probably nudged a few of you to think about sub Tenon opposed to sharp needle block. You have probably done this more than I have and can do things safely. Nevertheless, what I want to talk about is these patients with multiple comorbidities and eye surgery. Often you need to get help to manage their medical condition, especially if they’re on drugs that are going to cause complexity of surgery. Anticoagulant drugs with complex. I’ve had to write a policy for my own surgical teams here. It’s been a very fraught procedure because each surgical specialty has a different consideration and each medication has a different considerations. There are reversal treatments if you need to put them in place. Vitamin K for Warfarin or direct antagonists. There’s the use of bridging therapy if you need to keep someone relatively anticoagulated because the risk is so high. These need to be managed but they’re well out of the scope of a simple kind of eye unit. You need individuals who manage this a lot more to help you and guide you. Always be wary when there is a suggestion of sepsis present. You need to diagnosis and get early antibiotics and on going observations. You have to potentially use trans — I want to wrap up this presentation and talk about sub Tenon block. This is something we’re very enthusiastic about. It’s the default technique for local anesthetic and it has pervaded across. It’s the default technique for Orbis and we have tried to show how this can be delivered safely and effectively. It is reliable and effective. This is often, if you can use high lure Ron days as the mixture of the anesthetic, depend on that, essentially the ability of the hyaluronidase to create that permeation of the local anesthetic more deeply. Otherwise, delivering the block and waiting will deliver the same effect. You avoid the sharp needle penetration. And these can be given much later. You may feel you have given a peribulbar block without the complications but the complications can present later on. With the sub Tenon you can give larger volumes. Up to 15 ml into the orbital space. You can do this very effectively with the sub Tenon technique as long as you’re conscious of the possibility for proptosis. The other thing about sub Tenon is it’s easy to top off the block. A very long surgery can be topped up as a sub Tenon. It’s suitable for all types of eye surgery. Whatever you have thought of or read about on this topic, we have done every time of eye surgery here. All types of surgery, enucleations under local blocks. For pregnant patients, the local block allows us to do anything they need. There are some — into this and I accept this. The cons are you need additional equipment. But this can come from the surgical set. The Moorfields forcepts, Wescott scissors, and the spectrum can come from the surgical setting if necessary. And the cannula is the only difficult thing. You don’t need to use the preformed metal cannulas. And will is a learning curve. But they’re minor but still disconcerting. You can get chemosis and bleeding. As a quick visual. That’s the standard set delivered to us on the left. What I tend to use is the sheath of an IV cannula with the needle taken out and that avoids the trauma that the — can possibly provide over the type of the — but also means when working in environments that don’t have the preformed metal cannulas, I have a delivery method that works. That’s my only point of preaching about the sub Tenons. I would say they are useful in your armament of different techniques. I’m now going to stop. I’m going to say thank you very much for listening. We should try to address some of the questions that came up along the way. Okay. First question I can answer is from Dr. Endale. Sorry, did I disappear, I apologize. Am I present again? >> Yes, you are. >> Thank you. So first question. After giving the maximum tolerable retro bulbar anesthesia, if the subject is still in pain, what would you do? One of the things I’m saying is the sub Tenon allows you to carry on topping up. It’s hard to keep topping up because of the risk of needle penetration continues and doesn’t dissipate. Doing it more than once gives you cause for concern. It’s hard for many practitioners to believe that a retro bulbar can be replicated by a sub Tenon but we’re able to persuade people this is the case. Many doctors come to visit us from elsewhere and are surprised what the sub Tenon can achieve. That’s a brief answer. Other than, that I wouldn’t get myself caught in that situation because the sub Tenon is my choice. There is a question in Spanish. I might need some help with that. I will move forward until we come back to that. what other methods to reduce the preop and intra-op anxiety in a patient? What you’re asking me is something I might have covered already about preparing the patient from the process and understanding what is going happen and make sure they are fed and watered. We have volunteers that come and hold the hands of patients. Human touch counts for more than anything I can give IV. Other than that, we do use anxiolytic drugs given IV or orally. That may not be present for you. If it isn’t, I think the other practical measures will help you. What’s the best technique for anesthesia for preterm infants undergoing laser therapy for ROP. You have essentially presented me with one of my scariest moments in anesthesia when I was volunteering for a Mongolian flying hospital mission and I was asked to do exactly what you’re describing. I’m not sure I’m going to give you the best possible answer because I did something that might not feel like it’s going to work. As a technique it can be very powerful. That was, these are small infants. They’re very, very susceptible to post prandial sleeping. What we did was we fasted these children up to a point and then asked for the mother to breast-feed the child. We swaddled the child and held the child in our arms for the surgeon to undergo the laser. Under the course of that 5 to 10 minutes this was adequate. Longer lasering is not possible. But the two things we achieved using this procedure is one laser and intravitreal injections. This is a much much more conducive way to managing premature babies with certain morbidities associate with them. What would you do otherwise? You would have to use the traditional sedative technique that you have present in the NICU or whatever setting you’re in. That drug changes all the time in the UK. I wouldn’t tell you absolutely what is the ideal. Things currently that are fashionable is dexameth — what you’re most familiar with. Knowing how it can create a state of calmness in the child in the briefest period and swaddling the child and holding them still can be the best way to proceed. The best retinal exams — you’re right. I don’t know the answer to that one. Sorry Iddi. That’s a fantastic question. I wish I could give you a answer for really difficult adult patients. We can give them a general anesthetic here. But if you’re doing this regularly for many patients in a difficult environment, I can say that is just not possible. There would be some oral drug you might be able to try but it’s trial and error over the course of many different drugs until you find the one that hits the appropriate window of calming the patient long enough for you to achieve that and what is available without difficulty. That’s the best answer I can give you. Sorry about that. Role of remote monitoring of vitals preop. Yes. This is primary care. In primary care the doctors seeing the patients are measuring these things and able to tell us what the blood pressures are and whether these are relevant to our concerns. If they are clearly running hypertension in their normal state at home, they need to be treated before they come to surgery to the point that it’s problematic and causing risk to them for end-organ damage. That is what I’m talking about. It should be done by primary care ahead of us. If you don’t have eye drops, is it safe to apply Lignocaine topically. I think that’s probably the best thing you can do. Clearly, it’s not going to cross the mucosal barrier as effectively as the other drugs like Tetracaine. That’s the chemical nature of the drug. Can you give a small conjunctival injection, I don’t know. One thing that we, again this is not going to be helpful to you. This was an expensive component to what we tried here once. For strabismus surgery, we tried lignocaine as a gel formation. It was prohibitively expensive. So lignocaine with a gel preparation, no preservative present. A small blob of that has a good effect. It’s a period of contact on the conjunctiva and cornea. But I don’t have an easy answer for you. You work in a hard environment Iddi, I’m very respectful of what you’re trying to achieve there. How safe is general anesthesia. Try to avoid it if you can. The laser has to be super quick. If you need to do a GA for them. It’s a combination of NICU doctors and anesthetic doctors. Preemie babies, the risks are considerable and the risk of complication of a simple anesthetic is profound. In local anesthesia, what is my preference. Without a doubt sub Tenon. I would never do a retro bulbar. Peribulbar, I can see the value and I can see why so many people around the world do it effectively and achieve a good outcome as a result. But I do think there should be a gentle switch towards using more sub Tenons. Ideally, sharing with the surgical set at the out set of the procedure will allow you to do these blocks that are really, really safe. But very effective. For semi-urgent cases, is it possibly to defer the GA for two weeks. Possibly. You’re going down a slope of risk and probably have less of a problem. The one little bit of evidence that exists around this problem of GA complications is six weeks turn around time. If it’s elective you always say six weeks. But maybe waiting two weeks. The interventions that I was describing, the humidification and use of physio therapy and antibiotics may come into being effective in that two-week period. Is the cannula safe to be reused after the sterilization and sub Tenon block? Yes. I respect you for having to think about this. Not something I ever have to think about. It’s a shame we throw away so much in the UK. I would think so. It’s not a sharp needle. There should be no tissue retained upon it. If it’s flushed and sterilized the same as the other instruments, it should be fine. Why not consider the sheath of the IV cannula. I know it’s one less in your box, but that’s a cheap and safe way to make it a single use entity. Just a thought. Can bupivacaine be added to lignocaine. Yes. You have brought this to my mind. We always use a combination. For the longer procedures, we would always give a combination of bupivacaine and lignocaine. Just to achieve longevity of action. If you’re lucky enough to work in environments where you have the you by-cane isomeric, then you can go to the higher concentrations the higher concentration of bupivacaine has been associated with toxicity of the eye but not the other runs. Nevertheless, at Moorfields we only use bupivacaine. .5 percent bupivacaine and we use that in addition to lignocaine if appropriate or on its own to deliver a long acting local anesthetic block. What do you use for sedation before the blocks? If I’m after anxiolysis where I want them to be relaxed and calm. I try to use the smallest dose of one of two agents. That is midazolam 1 to 2 mg. And my favorite drug is alfentanil. Much shorter in the presence in the body. It’s re-sited in the fat quickly and is an acute onset profound analgesic. But, whatever you are comfortable using is the right thing to use for sedation. Nothing slow acting. We’ve been using Dex recently. We have access to midazolam (ph.) When I’m going the local anesthetic techniques and much more profound surgical interventions. If it’s not a pregnant patient that I literally say I’m going to give you a blocker and hold your hand so we avoid fetal interference of drugs. If it’s an elderly person, I give them a local and then an infusion of sedation. That’s much more deep sedation. And treated like a general anesthetic. We don’t necessarily do airway interventions but in those cases, we may run infusions of propofol. Next one. Frequently patients present with tachycardia but have known AF on medication. Should these patients be on anesthetic supported list? Thank you for the question. Caused no end of controversy where we work. The surgeons feel uncomfortable. There are complications with the atrial fibrillation and the lack of anyone present. The reality is it rarely happens and is rarely a problem. Someone truly over 120 in atrial fibrillation should not be ignored. Whether you do the surgery or not depends on the speed of the surgery. I have encouraged surgeons to complete the operation despite this being present. If we don’t do the surgery, the patient may go without the surgery for months or a year and I feel the patient can be managed in that situation. I ensure the patient is followed up and potential management for that. We often get advice from our cardiologists, try a small dose, 2.5 and things like that to slow them down then and there and allow whatever else needs to happen. That one is up for discussion. That is one where you win your friends in the anesthetic service if you’re a surgeon and say I would feel more comfortable if you support these patients. There’s very clear guidance on this one, the association [indiscernible] find it. It’s a clear 6 months and 3 months. We would not want to go near patients with recent MI or CVA. Recent MI is 6 months and we expect them to be fully investigated for complications. CVA is 3 months. And when those patients come for surgery, it has to be present surgery and the elective surgeries we wait a year if we can. How can I now sooner incase of needle damage for optic nerve. Not sure what your question is Dr. Mumim. Sorry. I’m going to move past that one. Dr. Day. What method for vitrectomy surgery, under local anesthetic block. Sub Tenon. Every patient is told that’s the default way of managing the surgery. Some patients we often sedation because they’re not going to cooperate. And a much smaller group is given a general anesthetic. The much smaller group are infants and children. Sometimes patients with dementia although it seems fraught whether we’re going to give a demented patient with other comorbidities a general anesthesia. Definitely for cataract surgery the benefits are present. But vitreal surgery, you can argue. If it’s a macular detachment, yes, I would give that patient a general anesthetic. But the default answer is local and sub Tenon block. Is sub Tenon safe for retro bulbar hemorrhage. I’m sure you kept yourself anonymous. That is a really good question. If the patient is fully anticoagulated would you feel comfortable using a sub Tenon. I would. I use the soft insert of an IV cannula. There is no metallic component of that. You can argue a preformed metal cannula can cause damage and bleeding if you push hard enough. The likelihood if you’re concerned, you will be careful in terms of insertion. And you are going to know that any — may cause bleeding. Are there recorded events of this, I think one or two recorded events around the world but in patients with such complicated medical histories that perhaps the problem was going to happen anyway. There is one recorded event in the UK of a patient dying at the end of the needle with a sub Tenon. But this patient was 92 years-old with other comorbidities. Perhaps their time had come and the delivery of the sub Tenon was not the precipitant. What size cannula do you use? The standard preformed metal can yule las are 90 gauge. The ones that I use is, IV cannula is a 22 gauge. I find that to be the ideal size. Kathy, you’re welcome to take this presentation. I’m sure Orbis will be happy to provide it for you. We don’t have the best protocols. I have to say like many hospitals around the world, we have established practice but less clear protocols. We often accept what is told to us by our governing bodies. And then we deviate a little bit. Especially in diabetic control. That was an area I didn’t bring up. Diabetic control because I think it’s a mess. We recognize people have got very high blood sugars, may never get low blood sugars and waiting for them to do so defers the surgery to the point where it’s irrelevant. There are guidances that exist because they’re very global anesthetic surgical care and they don’t always have value to us as eye doctors. Any consideration to look for patients with — yes. Common. Maybe this is a patient group I should bring up if I do this again. Atrial fibrillation. The thing about atrial fibrillation is there is a risk if the patients are uncontrolled. If you’re rate controlled, there is no concern to go ahead. If you’re rate controlled and on a novel or anticoagulant. There is no concern to go ahead. Phaco surgery should not have any complications associated with bleeding even with a sub Tenon block where there is redness because of the fact that you’re going to penetrate that layer in a patient with anti-coagulation. No outcome problems related to that. The problems are where the patient has atrial fibrillation and a concentration from that: They may precipitate skin changes or get to the point where the rate is so high that unless it’s corrected, there is risk of further degenerative rhythm changes and then it becomes an adult life support situation. You manage the atrial fibrillation because that’s the primary thing. Do we treat atrial fibrillation ourselves, no. We never do that. It’s a chronic disorder and a chronic treatment. We defer the patient for treatment if we felt the rate was putting them at risk during the surgical period. I would say this is more important. Get this sorted out by a cardiologist. They will do echo ands look for a throbbing bus and atrial fibrillation and treat you appropriately. There is a big trend in this country for ablation therapy. I don’t have an opinion on that. But they at least start medications. The doses of the medication should not cause any reason for you not to do cataract surgery under phaco. Do you select patients [inaudible] some yes and some no. Depends on the patient. There are some patients where I think you can only give the sub Tenon block or any type of block and get close — by sedating them. You can’t get close to their eye because they clench it or whatever. And the only way to get on board is briefly sedate them. What is your experience of patients — dementia, I wish I could say I’m an expert. I’m far from: I seem to have acquired a role in my hospital for giving general anesthesia to dementia patient. That is not a high skill base on my part, it reflects the fact that I kind of recognize as much harm as I will do with anesthetics, which I will do, but whatever harm I do, I am very sure the benefit of the surgery, especially for cataracts is greater. With psychosis management, again, I doubt very much that I’m dealing with the patients that have extreme psychotic patients as you’re dealing with in your situations. My patients come to me very well controlled on a good package of pharmacology and it’s not a problem. We’re aware of the drug interactions and continue and use general anesthetic on these patients. But here’s the really important thing, I don’t give a general anesthetic to every demented or psychotic patient. I don’t think it’s necessary. Having a sense of how the patient behaves by spending ten minutes with them and talking to their relatives and understanding what is going to precipitate bad behavior, agitation or disturbance or otherwise can be more useful than not. My other mother-in-law before she passed away needed cataract surgery. I didn’t want anyone to counsel her because I knew she would have benefit and she lived a very happy 6 months after that. On that occasion. I did everything I could. A small amount of propofol on that occasion and I held her head physically with my own hands so she wouldn’t move while the surgery was taking place. Sometimes we can stretch ourselves as far as we need to do get these patients through an operation. And especially if you’re working with a surgeon who understands the lengths you are going to, they will make sure they do what is needed and no more. And teaching surgeons the importance of doing what is needed and no more is a really important part of their surgical learning. I have some fantastic surgeons that know they need to be in and out of the eye in the 12 minutes that a contact racket operation should take most people. A lot of you probably do quicker still. That makes a real difference in these patients. This is going back to the diabetes and why. Dr. Han, there is a lecture in itself. We extrapolate the everyday from other types of studies that look at poor blood sugar control in cardiac surgery, vascular surgery and go oh my god, look at the problems this causes. Does I cause the same problem in ophthalmic surgery? No evidence. No evidence at all. And I think we’ve handcuffed ourselves to try to follow the guidance presented to us for other types of surgery. As much as possible we should try to improve patient’s blood sugar before surgery. Absolutely. No doubt about that. But the patients that come with diabetic complications that need to have this surgery because if they don’t they lose their eyesight. You need to make a call and say this is as good as it gets for this patient, let’s treat them. But we are extrapolating evidence and the evidence is good evidence because it’s about micro vascular changes, the risks of infection and the risks of poor wound healing. All of which are present in other types of surgery but rarely present the same way in ophthalmic surgery. Dr. V. Allergy to local anesthetic and lignocaine is due to high lace — let’s face it. There is never any allergy to adrenaline. It’s a natural substance. Do get allergy to Hylase. You can get a rather sort of, idiosyncratic reaction. We rarely see it. We use it a considerable amount here. That is not evidence. I don’t believe Hylase is as profound as perceived. Do you get local anesthetic allergies, yes, you do indeed and people can sometimes have this proven with skin testing and otherwise. In which case we switch local anesthetic and use bupivacaine instead. Rarely have we had to use prilocaine. But you know, we are not that extended in our choice of locals as you might imagine. So we do make that choice based on that. I hope that answered your question. Dr. Dey, if the effect of anesthesia dissolves between the process what should we do? I think what you’re trying to say maybe is if you lose the efficacy of the anesthetic, what do you do. Local anesthetic block, the sub Tenon is so useful because you can top it off. It’s easy to top off. I’m very proud if I manage to put a patient through a 3-hour operation and I don’t need to top off. But I don’t want the patient to lie there in pain. I top off and you talk to the nurse and make sure there is something to top off with. Volume are never that profound. If you think about the duration of time passing, even if you have given what you feel like is close to the toxic dose of the anesthetic two hours ago, you should be able to top off with a small amount later on. Which type of anesthesia for patients with arrhythmia who need muscle surgery general or local? Good question. Not easy to answer. But what you’re tapping into is can you do strabismus surgery under local. You can. Very much used by us. In the time when we are bridging COVID and we were trying to avoid general anesthetics in the unknown population for COVID infection, we switched a lot of patients over to local thinking it would be a struggle. Thinking it would be difficult to do. But you can comfortable do strabismus surgery with a sub Tenon block. A good global anesthetic of the eye would achieve sufficient anesthesia. It’s more likely than a general to Brock the cardiac reflex. You’re blocking the afferent more than the efferent. We give something anti-vagal to start the tachycardia. But with a local, you block the afferent loop of that and may even stop the pulling of the muscles from creating a bradycardic response. If you do adjustable splint surgery where you want to allow the surgeon to create different tension in the muscles to adjust visual outcomes, it’s quite difficult with the local block. It’s not impossible. We have done small dose, few volumes, full mls and allowed the surgeon to proceed and the patient recovered from the local to do the adjustment. There is a question if there is latency around the muscles. For fixed muscle strabismus surgery, it’s entirely feasible. And for the patient that you’re describing, I would want do that under local. I would use a bit of sedation and probably use some analgesic sedation. Drugs that have a sedative effect but are profoundly analgesic. That’s the perfect combination for this type of patient. Dr. Kumar. In which cases will you definitely stop the anti-platelet drugs before surgery? Good question. Are there any absolutes to this? Probably. Definitely not in cataract surgery. Most often than not the concern in retinal surgery, rarely stop them. Where we would is you would say, you have a large area to delaminate this. Is a fragile vasculature because they’re diabetic. I think it’s probably a better idea for you not to have a needle in the eye and that’s a condition where we do that. Where the surgeon maybe dealing with an ocular tumor or a biopsy. Those are few. Most of the retinal detachment surgeries that we see, not at all, they wouldn’t be stopped. Glaucoma is really tricky. This is surface surgery. They can potentially carry on with the surgery. The worry of bleeding is so profound this is a discussion you have to have with them. I can clearly understand that someone is going to put a large tube in and they’re worried about blood scarring up the area. They will probably use based on the evidence some anti-scarring therapy. But blood in itself is still a problem. In reality, our surgeons often use a reasonable amount of vasoconstriction on the eye and bleeding is less of a problem with those patients than you imagine. Strabismus surgery, again, you would think it should be a concern but this is another discussed event for the surgeon. More often than not easy. Where I’m edging towards is where the problems do arise. Ocular plastic surgeons that work on the territory around the eye. They would not want anti-platelet drugs given to their patient and we come to a level of compromise in working out what patients are safe to be stopped and what patients aren’t. If you’re doing bony work or orbital surgery, we accept this is not a territory you want to go into where there is uncontrolled bleeding. It’s not easy to apply a hemostatic approach. The oncology surgeons I work with who will do things like radioactive plaque for brachytherapy or markers for proton beam therapy. I’m not sure if this is familiar for to audience, then it’s again up for discussion. They would prefer these drugs to be stopped but if we say to them, this is actually not negotiable, they can work around that. And at least one of my oncology surgeons is very good at essentially removing the eye, not with a knife cutting or a scissor cutting technique but with a metal tie. I’m trying to think of the appropriate word for it. But essentially sealing the vessels and the tissues with a capable tie. That is a very effective way to stop the bleeding. Slightly mixed answer. We do have a policy that is out there and we followed royal college guidance and that was a joint part of the royal college of ophthalmologists that wrote this wonderful document for our policy. That would be worth your finding. This is my final question, what concentration of bupivacaine and which is safer heavy or plain bupivacaine. You’re entering territory when you talk about heavy bupivacaine. We never need to use heavy bupivacaine for the eye. We use plain. We never use adrenaline laced for the blocks. We always use .5 percent. We always know which drug we’re picking up. We don’t have different concentrations, we just use the one concentration. As a result, the volumes effects the mass that you’re delivering. If you’re thinking about what concentrations to use and say you had a small child and wanted to give a larger volume to, I would say there is no problem in using .25 percent if you wanted to if you want to have a larger volume delivered. We never really use that larger volume of drugs for the local anesthetic blocks around the eye and .5 bupivacaine works very well. Thank you very much.

Last Updated: May 15, 2024

4 thoughts on “Lecture: Conversations With an Ophthalmic Anesthetist: Topics We Should All Know”

  1. A 60 years old female has tingling sensation in her right foot and decrease her height over the past few years .she doesn’t do household work and menopause occur 12 years ago .she took NSAID tablets which alleviate her pain ….the above scenario is the case of which disease


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