effect of retrobulbar anaesthesia on intraocular pressure and ocular blood flow

To study the effect of retrobulbar anaesthesia on intraocular presssure [lOP] and ocular blood flow [OBF]. Fourty eyes of 40 patients [who were prepared for cataract surgery] received retrobulbar anaesthesia. The patients were divided into 2 groups: group I [retrobulbar anaesthesia without hyaluronidase] and group II [retrobulbar anaesthesia with hyaluronidase]. We measured intraocular pressure [by applanation tonometry] as well as blood flow velocity and resistivity index of central retinal artery and short posterior ciliary arteries [by Doppler sonography] just before anaesthesia, I minute after anaesthesia, and 10 minutes after anaesthesia. Both groups showed significant elevations of intraocular pressure after 1 minute of anaesthetia: group I [+ 17.9% +/- 3.7%] and group II [+ 15.8% +/- 3.3%]. However, the intraocular pressure nearly returned back to its pre-anaesthetic measurement after 10 minutes of anaesthesia. As well, both groups showed significant reductions of ocular blood flow. Group I patients [retrobulbar anaesthesia without hyaluronidase] showed a significant drop of peak systolic velocity in both central retinal artery [- 26.6% +/- 8.0%] and short posterior ciliary arteries [- 18.8% +/- 5.2%] in the 1 minute post-anaesthetic measures, as well as a significant drop of peak systolic velocity in both central retinal artery [- 30.5% +/- 7.0%] and short posterior ciliary arteries [- 22.1% +/- 13.9%] in the 10 minute post-anaesthetic measures. Group II patients [retrobulbar anaesthesia with hyaluronidase] showed a significant drop of peak systolic velocity in both central retinal artery [- 22,0% +/- 6.9%] and short posterior ciliary arteries [- 15.1% +/- 5.9%] in the 1 minute post-anaesthetic measures, as well as a significant drop of peak systolic velocity in both central retinal artery [- 26.4% +/- 13.9%] and short posterior ciliary arteries [- 17.2% +/- 10.3%] in the 10 minute post-anaesthetic measures, Retrobulbar anaesthesia results in the reduction of both choroidal and retinal blood flows. Retrobulbar anaesthesia might carry the risk of visual loss in patients with compromised ocular blood flow before surgery. It may be safer to use other anaesthetic techniques [e.g. topical or subconjunctival] in patients with ocular vascular compromise

effect of retrobulbar anaesthesia on intraocular pressure and ocular blood flow

The aim of this work was to study the effect of retrobulbar anesthesia on intraocular pressure [IOP] and ocular blood flow [OBF]. Forty eyes of 40 patients [who were prepared for cataract surgery] received retrobulbar anesthesia. The patients were divided into two groups: Group I, retrobulbar anesthesia without hyaluronidase and group II, retrobulbar anesthesia with hyaluronidase. The study measured the intraocular pressure [by applanation tonometry] as well as blood flow velocity and resistivity index of the central retinal artery and short posterior ciliary arteries [by Doppler sonography] just before anesthesia, one minute after anesthesia and ten minutes after anesthesia. The study concluded that retrobulbar anesthesia results in the reduction of both choroidal and retinal blood flows. Retrobulbar anesthesia might carry the risk of visual loss in patients with compromised ocular blood flow before surgery. It may be safer to use other anesthetic techniques [e.g. topical or subconjunctival] in patients with ocular vascular compromise

Lactic acid as a predictor for erythrocyte transfusion in healthy preterm infants with anemia of prematurity

Up till now there is no guidelines for blood transfusion in healthy preterm infants. In this study we try to show if blood lactate measurement may be used as in index for transfusion in those preterms. The present study included 33 healthy preterm infants, received no medications except for theophyline and prophylactic antibiotics, required no intravenous fluids or oxygen therapy. They were divided into two groups, [group I] included 23 babies, given once transfusion according to the decision of physician in charge. The main indications for transfusion were Hb below 8 gm/dl, Hct value below 30% and poor weight gain. The remaining 10 babies were not transfused [group II] and used as a control to measure normal blood lactate. The infants in the two groups were subjected to thorough history, clinical examination and selective laboratory investigations including CBC and blood lactate measurement. The results of group I were compared with each other before and after transfusion and with that obtained from group II. Comparing data of group I with that of group II, significant increase in blood lactate and decrease in Hb, Hct and body weight were detected in group I before blood transfusion. Pre and post transfusion data were compared in group I, there were significant decrease in blood lactate levels and significant increase in Hb, Hct and body weight, after transfusion. Blood lactate had a high specificity 100% and sensitivity 91.3%. We can conclude that measurement of blood lactate level as an indicator of early tissue hypoxia could identify otherwise healthy preterm infants who might benefit from blood transfusion. Thus, it may prevent unnecessary transfusion