Haemodynamic and intraocular pressure changes ...

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How did addition of clonidine in peribulbar (in the ropivacaine– clonidine group) cause sedation? ... ropivacaine, lignocaine and clonidine combination during.
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Letters to Editor

In the methodology section, it was written that the surgeon and the patient assessed quality of block. How did the patient assess this? In our opinion, the authors should have used an applanation (hand held or some other form) tonometer instead of the Schiotz tonometer as it does not give accurate readings. Ropivacaine is said to have a vasoconstrictive effect, which helps to reduce the intraocular pressure (IOP). At the same time, superpinky ball and ocular massage was given to reduce the ocular pressure. We think that ocular massage should not have been given if the drug reduces the IOP. Does the drug have an effect on the optic nerve vessels causing damage to its fibres and affecting visual outcome after the phacoemulsification?

References 1.

B Khan, SJ Bajwa, R Vohra, S Singh, R Kaur, Vartika, et al. Comparative evaluation of ropivacaine and lignocaine with ropivacaine, lignocaine and clonidine combination during peribulbar anaesthesia for phacoemulsification cataract surgery. Indian J Anaesth 2012;56:21-6. 2. Duker JS, Belmont JB, Benson WE, Brooks HL, Brown GC, Federman JL, et al. Inadvertentglobe perforation during retrobulbar and peribulbar anesthesia. Patient characters, surgical management, and visualoutcome. Ophthalmology 1991;98:519-26. 3. Fichma RA. Use of topical anesthesia alone in cataractsurgery. J Cataract Refract Surg 1996;22:612-4. 4. Koch PS. Anterior chamber irrigation with unpreservedlidocaine 1% for anesthesia during cataract surgery. J Cataract Refract Surg 1997;23:551-4. 5. Koch PS. Efficacy of lidocaine 2% jelly as a topical agent in cataract surgery. J Cataract Refract Surg 1999;25:632-4. 6. Nicholson G, Sutton B, Hall GM. Ropivacaine for peribulbar anesthesia. Reg Anesth Pain Med 1999;24:337-40. Comment, 2001;26:491-2. Access this article online Quick response code

Reference no. 19 cited by the authors in support of reduction of IOP by clonidine, on Pubmed search by us, states that there is no significant difference in baseline IOP and post-peribulbar IOP. The authors say that the mild sedative effect of clonidine was an added advantage as the patients remained calm and composed during the entire surgical period and had better sedation scores than patients who were administered ropivacaine. How did addition of clonidine in peribulbar (in the ropivacaine– clonidine group) cause sedation? Was it because of good quality block in the ropivacaine–clonidine group or possibility of systemic absorption of clonidine? In case of systemic absorption, issues related to the systemic absorption of other anaesthetic agents used will arise. In conclusion, the authors say that ropivacaine is considered a good local anaesthetic agent available that has a favourable side-effect profile. Nevertheless, we have seen that 3 mL 2% xylocaine and 2 mL 0.5% bupivacaine does work for peribulbar anaesthesia in cataract surgery without any side-effects.

Rajesh S Joshi, Niraj K Prasad1 1

Vasantrao Naik Government Medical College, Yavatmal, Consultant Anesthesiologist, Orivision Nursing Home, Manish Nagar, Somalwada, Nagpur, Maharashtra, India Address for correspondence: Dr. Rajesh Subhash Joshi, 77, Panchatara Housing Society, Manish Nagar, Somalwada, Nagpur - 440 015, Maharashtra, India. E-mail: [email protected]

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DOI: 10.4103/0019-5049.98802

Haemodynamic and intraocular pressure changes during peribulbar anaesthesia with ropivacaine and clonidine in phacoemulsification cataract surgery Sir, It is really heartening to see the progress of the Indian Journal of Anaesthesia (IJA) over the last 2 years. The readership base has widened and so has the horizontal expansion and penetration into other specialities. The progress achieved so far has done the reputation of IJA a world of good in disseminating the knowledge and advancements in anaesthesiology to a much larger intellectual population. The critical comments can really help in improving the quality of the published articles in the journal to a large extent in the future. The identification of weaknesses, shortcomings and limitations can further help in improving the quality of the journal. Indian Journal of Anaesthesia | Vol. 56| Issue 3 | May-Jun 2012

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Letters to Editor

We welcome the critical appraisal of our article “Comparative evaluation of ropivacaine and lignocaine with ropivacaine, lignocaine and clonidine combination during peribulbar anaesthesia for phacoemulsification cataract surgery” by the concerned readers.[1] In fact, the entire study is based on the model of day care surgery, especially the camp-based surgery, which is widely practiced in this part of the world. As such, attempts were made to simulate the near-identical surgical conditions prevalent in the peripheral health sector. Topical anaesthesia is immensely popular with the practicing ophthalmologists, but peribulbar blocks are required in many circumstances such as in uncooperative patients. The anaesthetic, lignocaine 2% jelly, may provide good analgesia on topical application but somehow its use is still limited. Instillation of gel can make the surgical conditions more difficult due to its viscous nature. Secondly, it can also cause clouding of the cornea, which may again hamper the smooth operating conditions. We assume that the concerned readers should be well acquainted with this drawback of lignocaine jelly. The day care model has its own limitations during the follow-up of patients. The ophthalmology unit may not be functional for 24 h in a majority of the settings, and this can be another big limitation. Moreover, these patients come from far-off places and do a lot of travelling on the day of surgery, before and after the operation. In our day-to-day practice, we have received complaints in the past about discomfort in the operated eye, foreign body sensation and sometimes even pain. Although we prescribe mild analgesics for such complaints, providing them a prolonged period of analgesia was considered a better option, which finally led to the designing of the present study.

cardiovascular and neurological effects has been successfully established in the literature.[3] The same sentence has been supported by the readers also, where they have mentioned that ropivacaine has a higher threshold for central nervous system toxicity than bupivacaine. Patient’s assessment was based on a subjective questionnaire, which included queries such as preoperative anxiety, pain during block, perioperative anxiety, discomfort and pain, post-operative pain and discomfort. Because of the limitations of word length and inclusion of minimum tables and figures in the manuscript, this questionnaire could not be included. Applanation tonometer is the gold standard measurement in ophthalmology, but, as mentioned previously, this model was simulating day care surgery in peripheral health sector set-ups where the availability of such costly equipment is a big limiting factor. Also, the applanation tonometer requires thorough training before its use and does consume a little higher time as compared with the Schiotz tonometer, as the former has to be cleaned every time it is used on different patients. However, newer techniques are available these days that are more accurate than Goldmann applanation tonometry, such as dynamic contour tonometry, which measures intraocular pressure with more precision and accuracy as well as with a very low inter- and intraobserver variability.[4] But, such methods and techniques are difficult to apply and work out at peripheral health sectors with limited resources. The readers have misunderstood here as ocular massage was never given and only orbital mechanical compression was exerted with “pinky” rubber ball. This was very useful in cases where the eye became tense (like deep set eyes), and orbital mechanical compression is indicated in such situations.

The choice of ropivacaine over other anaesthetics was dictated by its ability to cause lesser and shorter duration of motor blockade at identical doses as compared with bupivacaine. However, the prolonged sensory analgesia with ropivacaine can be useful in day care surgery.[2] The study with ropivacaine, clonidine and dexmedetomidine is already going on for vitroretinal surgeries.

Sedation with clonidine occurs due to central actions on alpha-2 adrenergic receptors. Whatever drug is injected in a regional space does get absorbed to some extent before finally getting metabolized. Otherwise, the pharmacodynamic sciences would have become obsolete and we could have got an unending concentration of injected drugs at local spaces.

The age range of the patients was 50–70 years, and the same was missed in the abstract during corrections of proofs. The safety of ropivacaine with regard to

Although lignocaine and bupivacaine have been traditionally used for achieving the peribulbar block, the above-mentioned merits of ropivacaine

Indian Journal of Anaesthesia | Vol. 56| Issue 3 | May-Jun 2012

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Letters to Editor

as compared with bupivacaine mandate the use of ropivacaine in ocular surgeries as well.

Acknowledgments The entire piece of work was carried out at the Gian Sagar Medical College and Hospital, Banur, Patiala, Punjab.

Balbir Khan, Sukhminder Jit Singh Bajwa1, Ravi Vohra, Sukhwinder Singh, Rajwinder Kaur, Vartika, Asha Departments of Ophthalmology and 1Anaesthesiology & Intensive Care Medicine, Gian Sagar Medical College and Hospital, Ram Nagar, Banur, Punjab, India Address for correspondence: Dr. Sukhminder Jit Singh Bajwa, House No-27-A, Ratan Nagar, Tripuri, Patiala - 147 001, Punjab, India. E-mail: [email protected]

References 1.

Khan B, Bajwa SJ, Vohra R, Singh S, Kaur R, Vartika, Asha. Comparative evaluation of ropivacaine and lignocaine with ropivacaine, lignocaine and clonidine combination during peribulbar anaesthesia for phacoemulsification cataract surgery. Indian J Anaesth 2012;56:21-6. 2. De Kock M, Gautier P, Fanard L, Hody JL, Lavand’homme P. Intrathecal ropivacaine and clonidine for ambulatory knee arthroscopy: A dose-response study. Anesthesiology 2001;94:574-8. 3. Hansen TG, Ilett KF, Lim SI, Reid C, Hackett LP, Bergesio R, et al. Pharmacokinetics and clinical efficacy of long-term postoperative epidural ropivacaine infusion in children. Br J Anaesth 2000;85:347-53. 4. Bochmann F, Kaufmann C, Thiel MA. Dynamic contour tonometry versus Goldmann applanation tonometry: Challenging the gold standard. Expert Rev Ophthalmol 2010;5:743-9. Access this article online Quick response code Website: www.ijaweb.org

DOI: 10.4103/0019-5049.98803

Tranexamic acid in total knee replacement surgeries: Some concerns Sir, We read with great interest the recent article by 320

Gautam et al.[1] on tranexamic acid (TXA) and blood loss during total knee replacement surgeries (TKR). However, we have a few concerns in interpreting the results of the same. Firstly, author claims it to be the first of its kind study in North Indian population. But there is ample literature on the effect of TXA on reducing the blood loss during orthopaedic surgeries. Infact, a similar study was conducted by us on north Indian population only, also published in Indian Journal of Anaesthesia way back in 2009.[2] Secondly, the fibrinolysis activation is a cascade phenomenon, which is most easily inhibited in its earlier phases. Once it is set in, the efficacy of TXA markedly decreases. It is surprising that, the authors have given TXA before deflation of tourniquet (after the surgery is complete) and still were able to show a marked reduction in the blood loss (more than reported in literature). The literature suggests that the TXA is most effective once it is given before the incision.[3-5] Moreover, the fibrinolytic response after trauma is biphasic with an increased activity during the first hours, followed by a shutdown that peaks at about 24 hours. Thus, suppression of fibrinolysis from the beginning of the operation may be more effective than only at the time of the peak of hyperfibrinolysis later. So it would have been better if the drug is administered at the start of surgery (before tourniquet inflation) and then continued perioperatively. Thirdly, the temperature of the theatre is generally kept lower (around 20 degrees) in joint replacement surgeries. Such a low temperature can lead to hypothermia, platelet dysfunction, coagulation abnormalities and increases perioperative bleeding. [6] So, one should monitor core temperature and take measures (forced air warming, warm fluids, etc.) to minimise the induced hypothermia. But neither OT temperature nor core temperature were monitored. Moreover, no measures were taken to reduce hypothermia. This may have been a confounding variable and may have resulted in a greater blood loss in the control group patients. Fourthly, the duration of tourniquet time and timing of its deflation (whether it was deflated before closing or after bandaging) is not mentioned. This may also have affected the results because the bleeding is more if tourniquet is deflated intraoperatively. Moreover, the prolonged use of tourniquet can increase the Indian Journal of Anaesthesia | Vol. 56| Issue 3 | May-Jun 2012