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PurposeTo determine by B-scan ultrasonography if the addition of hyaluronidase affects the dispersal of anaesthetic fluid after sub-Tenon's injection.DesignSingle-centre prospective randomised double-blind study.Materials and methodsWe performed a trial in 19 patients who were randomised to receive 5 ml of lidocaine 2% alone, or with hyaluronidase 15 IU/ml. A pre-anaesthetic B-scan ultrasound was performed followed by a standard infero-nasal sub-Tenon's injection. Further B-scan ultrasound studies were performed at 1, 3, and 5 min recording depth of local anaesthetic fluid. Data was analysed with Fisher's exact test and Student's t-test where appropriate. Results were considered significant when P<0.05.ResultsThe maximum depth of local anaesthetic was significantly less in the hyaluronidase group than the control group at 3 and 5 min (0.79 vs1.65 mm, P-value 0.01 and 0.43 vs1.52 mm, P-value 0.002 respectively). There were no statistically significant differences in the akinesia, pain and surgical satisfaction scores between the two groups.ConclusionsThe addition of hyaluronidase significantly augments the dispersal of local anaesthetic fluid, as measured by B-scan ultrasonography.Eye (2008) 22, 1065–1068; doi:10.1038/sj.eye.6702860; published online 25 May 2007 [ABSTRACT FROM AUTHOR]

Hospital computerised records were reviewed to identify patients who had undergone splenectomy, then chart their platelet count before and for the 5 days after the operation. A pre-operative platelet count less than 100 × 109.l−1 occurred in 66% of leukaemia ( n = 35), 56% of lymphoma ( n = 41) and 5% of solid tumour ( n = 39) patients. Platelet supplementation prior to epidural catheter insertion may reduce the risks of spinal bleeding. However, accidental catheter removal during a postoperative period of thrombocytopenia may lead to formation of an epidural haematoma. The lowest postoperative platelet count was less than 100 × 109.l−1 in 66% of leukaemia, 27% of lymphoma and 13% of solid tumour patients. Platelet counts varied considerably, so predicting an individual patient's postoperative nadir from the pre-operative count would be impossible. Consequently, placement of an epidural catheter in many of these patients could expose them to an increased risk of spinal bleeding if the catheter is removed accidentally. [ABSTRACT FROM AUTHOR]

Background: Ultrasound (US) guidance reduces complications and increases accuracy during internal jugular vein (IJV) cannulation. The subclavian vein (SCV) is popular but is less amenable to US guidance. The axillary vein (AxV), a direct continuation of the SCV, is an alternative, but to date, experience with US is limited to small case series.Methods: Retrospective procedural data were collected on 2586 sequential patients referred for insertion of tunnelled central venous access at a UK tertiary centre from 2004 to 2011.Results: A total of 99.8% of patients tolerated the procedure with local anaesthesia ± sedation; six patients had general anaesthesia. Twenty-six (1%) patients had uncorrected coagulopathy or thrombocytopenia. A total of 2572 (99.5%) of patients were cannulated successfully: right AxV 1644 cases, left AxV 279, right IJV 547, left IJV 89, other techniques 13, and 14 (0.5%) cases failed. The initial site chosen was successful in 96%. In patients who previously underwent long-term cannulation, 93.3% of lines were sited easily. Forty-eight (1.9%) procedural complications occurred.Conclusions: In this large analysis of US-guided central venous access in a complex patient group, the majority of patients were cannulated successfully and safely. The subset of patients undergoing AxV cannulation demonstrated a low rate of complications. The AxV route of access appears to be a safe and effective alternative to the IJV. [ABSTRACT FROM AUTHOR]

This article summarizes the study that examines the outcomes of adding hyaluronidase on minimum local anesthetic volume (MLAV) for sub-Tenon's anesthesia in patients with cataract extractions. Information on the drug dosage and the calculation of MLAV using Dixon and Massey formulae is presented. The article also states that hyaluronidase significantly reduces MLAV and improves predictability.

Presents a letter to the editor in response to the article which examines the potential of Patient-Controlled Alerting Device as a method for reducing anxiety in patients undergoing cataract extraction under local anesthesia, published in the previous issue of the "Eye."

Competing Interests: The authors declare that they have no conflicts of interest.

Background: Volumes of local anaesthetics for sub-Tenon's anaesthesia vary. Lower volumes produce less akinesia, whereas higher volumes increase chemosis and intra-ocular pressures. Hyaluronidase is often added to local anaesthetics to improve akinesia without increasing the volume of the injection, but this is controversial. This randomized, sequential allocation study examines the addition of hyaluronidase on the minimum local anaesthetic volume (MLAV) required for a sub-Tenon's block., Methods: Sixty-two patients having sub-Tenon's blocks for cataract surgery were randomized into two groups. The control group (n=31) received 2% w/v lidocaine and the study group (n=31) received 2% w/v lidocaine with hyaluronidase 15 IU ml(-1). Using parallel up-down sequential allocation from a 4 ml starting volume, the volumes in both groups were changed using a testing interval of 1 ml according to the quality of globe akinesia. The median effective local anaesthetic volume (MLAV) was calculated for both groups using probit regression., Results: The groups were similar for age, sex, and ocular axial length. The MLAV in the hyaluronidase group was 2.6 ml [95% confidence interval (CI), 2.1-3.l] and 6.4 ml (95% CI, 5.1-8.1) in the control group (P<0.002)., Conclusions: Hyaluronidase permits a significant 2.4-fold (95% CI, 1.8-3.4) reduction in MLAV for sub-Tenon's anaesthesia.

Purpose: To review the frequency of hemorrhagic complications with sub-Tenon's anesthesia in patients on aspirin, warfarin or clopidogrel., Setting: St. James's University Hospital, Leeds, United Kingdom., Methods: Data were collected prospectively for patients having elective phacoemulsification under sub-Tenon's anesthesia. Seventy-five patients were on aspirin, 65 were on warfarin, and 40 were on clopidogrel. Seventy-five patients on no anticoagulants were used as the control group. No changes in the anticoagulant regimen were made prior to surgery., Results: No sight-threatening hemorrhagic complications were noted, and no surgery was postponed or cancelled due to an anesthesic complication. Subconjunctival hemorrhage occurred in 19% in the control group, 40% in the clopidogrel group, 35% in the warfarin group, and 21% in the aspirin group. The warfarin and clopidogrel groups had the highest incidence of subconjunctival hemorrhage (P<.05). The incidence of hemorrhages involving more than 1 quadrant was highest in these 3 groups; however, this did not achieve statistical significance (P = .37, Fisher exact test)., Conclusion: Data from this study support the continued use of anticoagulant agents among routine users during cataract surgery using a sub-Tenon's block.

The currently available local anaesthetic agents are capable of providing high quality nerve blockade in a wide variety of clinical circumstances. Our understanding of the mechanisms and consequences of toxicity is increasing rapidly. Knowledge of the chemistry of local anaesthetics has enabled clinicians to exploit the increased safety of single isomer agents. However, the extent, if any, of this improvement in toxicity has yet to be proven. Established toxicity may be very difficult to treat and no specific reversing therapy is yet available. Until this occurs it is essential that practitioners of regional anaesthesia maintain their knowledge base and skill in techniques of administration of local anaesthetic, are able to recognise impending disaster, and constantly update their skills in resuscitation.

The fibrin assay system (FAS) has been designed to address the problem of in-situ diagnosis of central venous catheter (CVC) colonization. The FAS was evaluated in 12 critically ill patients with daily brushings, comparing results with culture of the catheter tip and blood. Data analysis of the FAS showed a sensitivity of 0 with a specificity of 1.0. The study was repeated in a further 12 high-risk patients with a single terminal brushing on catheter removal. This gave a sensitivity of 0.14 and a specificity of 0.8. Differences in sensitivity may be due to daily disruption of the endoluminal fibrin clot. Our results do not support the routine use of the FAS to detect CVC colonization in the intensive care unit.