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Anesthesia management during cataract surgery. Volume 1: evidence report. Volume 2: evidence tables and bibliography |
Lubomski L H, Magaziner J, Sprintz M, Kempen J, Reeves S W, Robinson K A, Bass E B |
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Authors' objectives To summarise the published literature on the risks and benefits associated with using one form of local anaesthesia over another, and the risks and benefits associated with different approaches to sedating the patient for cataract surgery.
Searching PubMed (up to 1999) and the Cochrane Library (Issue 1, 1999) were searched; the search strategy for PubMed was reported. In addition, 10 named ophthalmology and anaesthesia-related journals were handsearched, and the reference lists of relevant review articles and a sample of the included studies were checked. Only articles reported in English were included.
Study selection Study designs of evaluations included in the reviewControlled trials and case series with more than 100 cases were eligible.
Specific interventions included in the reviewStudies of local anaesthesia (with or without sedation) were eligible. Studies of general anaesthesia only were excluded. The local anaesthesia techniques used in the included studies were retrobulbar, peribulbar and sub-Tenon's blocks. Over half of the studies used additional agents, mainly hyaluronidase or epinephrine, for local block anaesthesia. Sedation was intravenous, intramuscular or oral.
Participants included in the reviewAdults undergoing cataract surgery were eligible.
Outcomes assessed in the reviewOutcomes related to the risks and benefits of the intervention were eligible. The main outcomes of interest for local anaesthesia were akinesia, pain experienced during administration of anaesthesia, pain experienced during cataract surgery, and ocular and systemic complications. The principle outcomes of interest for sedation were anxiety or pain control, haemodynamics and associated complications.
How were decisions on the relevance of primary studies made?Two reviewers independently assessed the identified articles. Any disagreements were resolved by the full study team.
Assessment of study quality The studies were assessed using a 32-item assessment tool, scored on a scale of 0 to 2, which covered the following domains: representativeness and patient selection; bias and confounding; intervention description; description of outcomes and patient drop-out; and, statistical quality and interpretation. An overall quality score (percentage) was calculated. Two reviewers independently assessed each study using a standardised form. Any disagreements were resolved by consensus, or through a third reviewer where necessary.
Data extraction The data were extracted by one reviewer using a standardised form and checked by a second reviewer. Information on the study design, intervention and relevant outcomes were extracted. Details of the intervention included: the local anaesthetic used; additional agents or techniques; the volume or number of drops of anaesthetic, and location; whether the block was facial or lid; the technique for cataract removal; the mean surgical time; and sedation.
Methods of synthesis How were the studies combined?The studies were combined in both a narrative and tabular format. The studies were grouped based on 33 specific questions in relation to local anaesthesia and 5 questions in relation to sedation. When a question involved a direct comparison of alternative techniques, evidence grades (strong, moderate, weak, insufficient) based on consensus were assigned to the synthesis. Indirect comparisons were also made, though these were not assigned an evidence grade.
How were differences between studies investigated?Differences between the studies were identified in the tables.
Results of the review A total of 141 studies met the inclusion criteria: 105 randomised controlled trials (RCTs) and 36 case series. Of these, 122 assessed local anaesthesia with or without sedation and 19 specifically focused on issues related to sedation. The number of surgeries using local anaesthesia techniques ranged from 20 to 570 in the RCTs, and from 100 to 4,000 in the case series. (These figures were based on the text; there are some discrepancies between the text and the number of studies in the appendix tables.)
Local anaesthesia techniques.
A range of methodological limitations was identified. The authors stated that these limited the inferences that could be drawn from much of the literature and made it difficult to compare, in a meaningful way, the rates of ocular or systemic complications associated with different local anaesthesia. The following evidence was graded as strong (A): peribulbar and retrobulbar anaesthesia produce equally good akinesia; there is less pain during topical anaesthesia than during administration of a peribulbar block; retrobulbar and peribulbar techniques produce equivalent pain control during cataract surgery; retrobulbar block results in less pain during cataract surgery than topical anaesthesia. The following evidence was rated as moderate (B): there is less pain during the administration of a subconjunctival/sub-Tenon's block than during retrobulbar block; intra-operative pain control using subconjunctival/sub-Tenon's is superior to retrobulbar block; there is less pain associated with peribulbar block during cataract surgery than with topical anaesthesia; pain control was improved by adding intracameral lidocaine to topical anaesthesia. For the remaining questions, the evidence was in the form of indirect comparisons or was graded as weak or insufficient to address the question.
Sedation techniques.
The authors stated that the synthesis of the evidence was limited by the heterogeneity of the outcomes reported. There was weak evidence (C) of an association between intravenous or intramuscular sedation and anxiety, pain relief and patient satisfaction. There was weak evidence that patient-controlled analgesia is an effective method of supplying intravenous sedation, but it results in an increased need for supplemental oxygen. For the remaining questions, the evidence was in the form of indirect comparisons or was graded as insufficient to address the question.
Cost information Cost information was reported. This was not based on the systematic review but on the analysis of a Medicare claims data set.
Authors' conclusions The authors stated that a variety of commonly used anaesthesia management strategies for cataract surgery appear to be safe and highly effective. Topical anaesthesia does not provide pain control that is as effective as injection techniques, although it is quite effective and avoids complications potentially associated with injection techniques. The authors also stated that there was only weak evidence that, during cataract surgery, intravenous or intramuscular sedation or analgesia improves anxiety control, pain relief and patient satisfaction.
CRD commentary The review criteria were clear in terms of the intervention, outcome, participants and outcomes of interest. Two relevant databases were searched, supplemented by handsearching. Studies may have been missed as there were no specific attempts to identify unpublished studies and only English language articles were included. Attempts to minimise error and bias were made: the study selection and quality assessment processes were carried out in duplicate and there was independent checking of the data extraction. Appropriate study details were tabulated. Study quality was assessed and reported for individual studies, and the findings were discussed in the context of study quality. Given the diversity of the studies included, a narrative synthesis was appropriate. The authors' overall conclusions appear to follow from the evidence presented though, given space limitations, it is not possible to comment on the conclusions for each of the 38 review questions.
Implications of the review for practice and research Practice: The authors stated that there is no need for a rigid guideline for anaesthesia care during cataract surgery, or for a change in current practice, as there is no evidence to indicate that one anaesthesia strategy is superior to any other.
Research: The authors stated that there is a need for good-quality clinical trials in this field. Specifically, to gain information on patient preferences for different forms of anaesthesia; to gain a better understanding of surgeon preferences; and to assess the cost-effectiveness of intravenous sedation and of monitoring by anaesthesia staff.
Funding Agency for Healthcare Research and Quality, contract number 290-097-0006.
Bibliographic details Lubomski L H, Magaziner J, Sprintz M, Kempen J, Reeves S W, Robinson K A, Bass E B. Anesthesia management during cataract surgery. Volume 1: evidence report. Volume 2: evidence tables and bibliography. Rockville, MD, USA: Agency for Healthcare Research and Quality. Evidence Report/Technology Assessment; 16. 2001 Other publications of related interest 1. Friedman DS, Bass EB, Lubomski LH, Fleisher LA, Kempen JH, Magaziner J, et al. Synthesis of the literature on the effectiveness of regional anaesthesia for cataract surgery. Opthalmology 2001;108:519-29. 2. Friedman DS, Bass EB, Lubomski LH, Fleisher LA, Kempen JH, Magaziner J, et al. The methodological quality of clinical trials on regional anaesthesia for cataract surgery. Opthalmology 2001;108:530-41.
Indexing Status Subject indexing assigned by CRD MeSH Anesthetics, Local; Cataract Extraction AccessionNumber 12003008006 Date bibliographic record published 31/12/2004 Date abstract record published 31/12/2004 Record Status This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn. |
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