Chandra M. Kumar

Visual experiences during cataract surgery: what anaesthesia providers should know

&NA; Recently published literature shows that most patients experience a variety of visual sensations during cataract surgery under local anaesthesia. Most patients (80‐100%) retain at least some light perception in the operated eye and many also experience a variety of other visual sensations during cataract surgery under regional ophthalmic anaesthesia (retrobulbar, peribulbar and sub‐Tenons blocks) or topical anaesthesia. The visual sensations experienced include perception of movements, flashes, colours, changes in brightness, or the sight of surgical instruments, the surgeons hands or fingers, or even the surgeon. These findings are clinically significant because 3‐16.2% of patients who had cataract surgery under either regional or topical anaesthesia were frightened by their intraoperative visual experience. Fear and anxiety may cause some patients to become uncooperative during the surgery and may also induce a sympathetic stress response that might cause hypertension, tachycardia with myocardial ischaemia, hyperventilation or an acute panic attack. These effects are especially undesirable as the majority of cataract patients are elderly and have concurrent medical problems. Besides increasing the risk of intraoperative complications, a frightening visual experience may decrease patient satisfaction. Appropriate preoperative counselling has been shown to be effective in reducing the patients fear. As most patients retain some visual function during cataract surgery under local anaesthesia, anaesthesia providers should be mindful of this phenomenon and offer appropriate preoperative information and counselling to their patients.

A review of sub-Tenon's block: current practice and recent development.

&NA; The place of sub‐Tenons block in ophthalmic surgery is now established. This block was introduced into clinical practice in the early 1990s as a simple, safe and effective technique. Since then, techniques have evolved, newer cannulae have been introduced and many complications, both minor as well as major, have been reported. This review deals with the recent developments in sub‐Tenons block.

Complications of Ophthalmic Regional Blocks: Their Treatment and Prevention

Complications following ophthalmic regional anaesthesia are rare but are reported during both needle (intraconal and extraconal blocks) and blunt cannula (sub-Tenon’s block) techniques. At present there is no perfect technique of ophthalmic regional anaesthesia. This article reports on the complications, treatment and prevention of commonly used ophthalmic regional blocks. Thorough knowledge of the measures required to deal with complications when they occur are of paramount importance for safe clinical practice.

Composition of the anaesthesia team: a European survey.

Background and objective The anaesthesia workforce in Europe is understaffed and may not meet the growing demands of surgery. In many European countries where responsibilities can be identified and a varying degree of task substitution occurs, the anaesthesia service is provided by a team of physician and nonphysician anaesthesia members. This study assesses the availability, as well as the roles and functions, of nonphysician anaesthesia team members in European countries. Methods A survey was carried out to examine differences in anaesthesia practices and the strength of the anaesthesia workforce in Europe. A questionnaire, seeking information about perioperative anaesthesia input by nonphysician anaesthesia team members, was sent to all the national representatives of the Union of European Medical Specialists Anaesthesiology section and the International Federation of Nurse Anaesthetists. Results The responses to the questionnaire revealed that each European country has its own unique type of nonphysician anaesthesia team member and the roles of these vary substantially. Their levels of organisation vary from country to country and whereas nurse anaesthetists are often well organised, circulation nurses are not. Conclusion The present study demonstrated the heterogeneity and variety of anaesthesia practices throughout Europe. Standardisation of the training and practice of European nurse anaesthetists is desirable for patient safety and quality of care if they seek to work in more than one European country. Those countries that anticipate a shortfall in the supply of anaesthesiologists should examine working models from other countries that currently work with fewer physicians and more nurse anaesthetists.

Ophthalmic regional anaesthesia.

Purpose of review To outline recent developments emphasizing the current literature on ophthalmic regional anaesthesia including modern sharp needle and blunt cannula sub-Tenons blocks. Recent findings Local anaesthesia is commonly used for ophthalmic surgery but the techniques and choice vary. Akinetic ophthalmic regional blocks such as intraconal and extraconal blocks with needles are generally safe, but although rare, serious sight and life-threatening complications continue to occur. Newer akinetic sub-Tenons block with a blunt cannula has emerged as a safer alternative to needle blocks, but although unusual, both sight and life-threatening complications have been reported. Summary At present, there is no absolutely safe ophthalmic regional block. It is imperative therefore to have a basic knowledge of anatomy and technique which reduce complications.

Sub-Tenon's block with an ultrashort cannula ☆ ☆☆

Purpose: To evaluate the effectiveness and safety of an orbital block using an ultrashort, wide‐bore blunt metal cannula to inject local anesthetic agents into the anterior sub‐Tenons space. Setting: Department of Ophthalmology, North Riding Infirmary, Middlesbrough, United Kingdom. Methods: Fifty‐nine consecutive patients having routine phacoemulsification with intraocular lens implantation were studied. Five milliliters of lidocaine 2% with adrenaline 1:200000 and hyaluronidase 150 units was injected into the anterior sub‐Tenons space in the inferonasal quadrant via a 16‐gauge, short (0.6 cm), blunt metal cannula. Horizontal and vertical movements were assessed before injection and 2, 4, and 6 minutes after injection (also at 8 and 10 minutes if akinesia was inadequate). The movements were scored from 0 (no movement) to 3 (full movement). Incyclotorsion and lid movements were assessed at the same intervals. In the first 15 patients, B‐scan ultrasonography was performed before, during, and 2 minutes after the injection. If the aggregate akinesia score was higher than 4 at 6 minutes, a supplementary injection was given. Pain during the injection and surgery was assessed using a 10‐point verbal rating score. The incidence, severity, and quadrant of chemosis and conjunctival hemorrhage were noted. Results: Forty‐eight patients (81.35%) had an aggregate akinesia score lower than 4 at 2 minutes and 58 (98.30%) at 4 minutes. One patient had an akinesia score higher than 4 at 6 minutes and required supplementary injection. Incyclotorsion was present in 42 patients (72.88%) at 2 minutes and in 19 (32.20%) at 4 minutes. Lid opening (levator function) was present in 33 patients (55.93%) at 2 minutes and in 19 (32.20%) at 4 minutes. Lid closure (orbicularis function) was present in 34 patients (57.62%) at 2 minutes and in 18 (30.50%) at 4 minutes. One patient required a supplementary injection at 10 minutes. Ultrasonography showed the injection caused rapid opening of sub‐Tenons space, with fluid spreading around the optic nerve. No pain on injection occurred in 67.79% of patients; 17 (28.81%) had a verbal rating score of 1, 1 (1.69%) had a score of 3, and 1 had a score of 5. No patient reported pain during surgery. A minor degree of chemosis and conjunctival hemorrhage occurred in 43 patients and 37 patients, respectively. Moderate chemosis occurred in 15 cases and severe chemosis in 1 case. Conclusions: Effective and predictable ocular anesthesia can be achieved using a blunt, ultrashort cannula for sub‐Tenons block. The technique greatly reduces the risks for globe perforation, muscle damage, and other serious complications.

A disposable plastic sub-Tenon cannula.

Reading Dr Willatts editorial exhorting our specialty to even greater efforts in the future initially provoked the old familiar feeling of guilt that I (and presumably my colleagues) should be doing much, much more. Happily this emotion soon passed, to be replaced with one of incredulity and, rather surprisingly (since I think by nature I am a placid fellow), anger. Coming from the Prime Minister, the five Ps sound, as one might expect, like yet more political sound bites. Coming from a senior and distinguished colleague who might be expected to represent the views from the `coalface they are rather surprising. As Clinical Director of a large department, I have just signed off the job plans of 37 consultant colleagues. All are working in excess of the European working time directive; so much for the `rigid three and a half hour session. All would agree that inadequate nursing levels on the wards and inadequate high dependency beds are a limiting factor in what they would like to achieve. The vast majority are still under 40 and are certainly not `conservative and traditional. They are certainly not `protectionist but imaginative and enthusiastic in doing their very best for patients with chronically limited resources in terms of staff and equipment. As for simply `Passing Gas, the Association and Royal College recent snapshot of activity showed that at any one time 50% of us are engaged in other clinical activities anyway. The Utopian solution that Dr Willatts proposes of greater working flexibility and the abandonment of normal working methods will not by themselves be enough to save the NHS. Indeed, the `rock of traditional medical practice may be all that has held it together for so long. Whatever the future holds, it is clear that Consultants cannot be expected to work any harder, or longer or with less support. Time must be given for teaching, lecture preparation, appraisal, assessment, revalidation, CME, audit, risk management, research, CEPOD, complaints and the many other calls on their time. In essence, enough is enough. For those of us without a higher award and with years left to work before retirement, the prospect is bleak indeed and hardly one of `Opportunity Knocks. Oh and Ive just thought of one more `P 1⁄4 its a decent Pay award.

A comparison of lidocaine 2% with levobupivacaine 0.75% for sub-Tenon's block

Background and objective: To compare the onset of action, and quality of block, of lidocaine 2% with levobupivacaine 0.75% for sub‐Tenons block in patients undergoing cataract surgery. Methods: We performed a two‐centre trial in 91 patients who were randomized to receive 4 mL of lidocaine 2% (n = 44) or levobupivacaine 0.75% (n = 47) for sub‐Tenons block, both with hyaluronidase 15 IU mL−1. Onset of akinesia was assessed every 2 min for 10 min. Numbers of patients requiring supplementary injections to achieve clinically satisfactory akinesia or rescue analgesia were recorded. Data were analyzed with Fishers exact test, U‐test and t‐test where appropriate. Results were considered significant when P < 0.05. Results: The speed of onset was statistically significantly faster for lidocaine compared to levobupivacaine (3.02 vs. 5.06 min, P < 0.001). There was no statistical difference in number of patients requiring a supplementary injection of local anaesthetic (levobupivacaine 3 vs. lidocaine 0, P = 0.24), rescue analgesia with topical tetracaine (levobupivacaine 0 vs. lidocaine 2, P = 0.5), or ocular akinesia scores at the completion of surgery (lidocaine 1.4 vs. levobupivacaine 1.6, P = 0.12). Pain scores measured by a verbal analogue scale were not significantly different for injection, perioperatively or postoperatively. Conclusions: Both agents produce a rapid onset of anaesthesia when used for sub‐Tenons block. The difference between the two agents, although statistically significant, is not clinically important.

Sedation during ophthalmic surgery.

&NA; Sedation is frequently used during ophthalmic regional anaesthesia. There is no ‘ideal drug for sedation or analgesia. Various drugs either alone or in combination have been used with different methods of administration. This review includes the roles of sedation, the pharmacology of drugs and the safety of sedation in patients undergoing ophthalmic surgery.

Needle-based blocks for the 21st century ophthalmology

Acta Ophthalmol. 2011: 89: 5–9