Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.36 (hyaluronidase)
 4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cataract surgery is the most frequent surgical procedure requiring anaesthesia in developed countries. It is performed mainly in elderly patients, who present with many coexisting diseases that induce subsequent hazards from general anaesthesia. Cataract anaesthesia is performed following various techniques of regional anaesthesia, which are detailed in this review. Needle block carries a low but real risk of complications, mainly because of needle misplacement. Correct teaching and training are mandatory to prevent complications. The main patient risk factor for inadvertent globe perforation is the presence of a myopic staphyloma. Retrobulbar block has been progressively phased out and replaced by peribulbar block, sub-Tenon's block (STB) or topical anaesthesia (TA). The requirement for very deep block with total akinesia has greatly decreased with the use of phacoemulsification for cataract surgery, allowing for use of TA or low-volume STB. However, non-akinesia techniques may give rise to impaired surgical conditions, which have the potential to result in surgical complications. A surgical approach to accessing sub-Tenon's space avoids needle block, but does not totally prevent complications. When deep anaesthesia is required, low-volume STB, performed using either the needle technique or a surgical approach, appears to be the technique of choice in terms of efficacy. Increasing the anaesthetic volume provides reproducible akinesia. Various local anaesthetics may be used, depending on their availability and respective properties. The most useful adjuvant to local anaesthetic is hyaluronidase.
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PMID:Anaesthesia for cataract surgery. 2003 Apr 30

Needle length is an important consideration in the safe conduct of ophthalmic blocks. A shorter needle could be used to insert the local anesthetic before the globe equator in the anterior orbit and to direct the injectable posteriorly using Honan's balloon to produce the desired effect. However, the use of pressure-reducing devices is not advisable in procedures with impaired retinal blood flow. The aim of this work was to demonstrate the effect of ocular compression with a Honan's balloon on the quality of peribulbar anesthesia when a short needle was used. The blockades were performed in 120 patients using a 27 G, half-inch-long needle. The needle was inserted into the inferotemporal quadrant adherent to the inferior orbital notch. The 7 to 10 ml of local anesthetic solution, consisting of bupivacaine 0.5%, lidocaine 2% in a ratio of 3:2 with hyaluronidase 5 U/ml, was injected followed by application of Honan's balloon or no compression. Ocular akinesia was assessed 10 min later; if inadequate, supplementary anesthesia was provided. No difference was detected in terms of volume injected, supplementation, and akinesia score. Under the conditions of this study, Honan's balloon did not contribute to the quality of the anterior orbit anesthesia, and the technique can be successfully used when ocular compression is contraindicated.
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PMID:Effect of pressure-reducing devices on the quality of anterior orbit anesthesia. 2140 53

It has been reported that alkalinisation of an anaesthetic medication enhances the rate of onset of regional anaesthesia. The purpose of this study therefore was to find out whether alkalinisation really hastened peribulbar anaesthesia as given prior to routine cataract surgery. Two hundred and forty otherwise healthy patients with bilateral cataracts were selected for this study irrespective of their demographic attributes. The first eye (group FE) received a routine peribulbar block with a standard solution of 6 ml of 2% lignocaine mixed with 15 IU/l units of sodium hyaluronidase at a pH of 4.6. The second eye (group SE) was taken up for surgery after one week and received a peribulbar block with 6 ml lignocaine 2% mixed with 7.5% sodium bicarbonate at a pH 7.4. The time taken for onset of akinesia in both the situations was measured to the last minute with the aid of a stop watch by an independent observer. Thirty-five per cent of patients in group FE had complete akinesia at the end of 5 minutes, another 60% at the end of 7 minutes and remaining 6% at 10 minutes. Sixty-eight per cent of patients in group SE had complete akinesia at the end of 5 minutes and 100% at the end of 7 minutes. No anaesthesia related ocular or systemic complications were seen in any group. Sodium bicarbonate buffered peribulbar block is faster than routine hyaluronidase augmented block with a reduced time of onset of akinesia.
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PMID:Sodium bicarbonate versus sodium hyaluronidase in ocular regional anaesthesia--a comparative study. 2302 28

Ophthalmic pediatric regional anesthesia has been widely described, but infrequently used. This review summarizes the available evidence supporting the use of conduction anesthesia in pediatric ophthalmic surgery. Key anatomic differences in axial length, intraocular pressure, and available orbital space between young children and adults impact conduct of ophthalmic regional anesthesia. The eye is near adult size at birth and completes its growth rapidly while the orbit does not. This results in significantly diminished extraocular orbital volumes for local anesthetic deposition. Needle-based blocks are categorized by relation of the needle to the extraocular muscle cone (ie, intraconal or extraconal) and in the cannula-based block, by description of the potential space deep to the Tenon capsule. In children, blocks are placed after induction of anesthesia by a pediatric anesthesiologist or ophthalmologist, via anatomic landmarks or under ultrasonography. Ocular conduction anesthesia confers several advantages for eye surgery including analgesia, akinesia, ablation of the oculocardiac reflex, and reduction of postoperative nausea and vomiting. Short (16 mm), blunt-tip needles are preferred because of altered globe-to-orbit ratios in children. Soft-tip cannulae of varying length have been demonstrated as safe in sub-Tenon blockade. Ultrasound technology facilitates direct, real-time visualization of needle position and local anesthetic spread and reduces inadvertent intraconal needle placement. The developing eye is vulnerable to thermal and mechanical insults, so ocular-rated transducers are mandated. The adjuvant hyaluronidase improves ocular akinesia, decreases local anesthetic dosage requirements, and improves initial block success; meanwhile, dexmedetomidine increases local anesthetic potency and prolongs duration of analgesia without an increase in adverse events. Intraconal blockade is a relative contraindication in neonates and infants, retinoblastoma surgery, and in the presence of posterior staphylomas and buphthalmos. Specific considerations include pertinent pediatric ophthalmologic topics, block placement in the syndromic child, and potential adverse effects associated with each technique. Recommendations based on our experience at a busy academic ophthalmologic tertiary referral center are provided.
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PMID:Regional Anesthesia for Pediatric Ophthalmic Surgery: A Review of the Literature. 3067 53


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