Abstract
Purpose:
The purpose of this study is to demonstrate how retinal and vitreous temperatures fluctuate during vitrectomy with room temperature infusion fluid and to demonstrate the extent to which the retina is cooled during routine vitreous surgery.
Methods:
Prospective study of 16 patients already schedule for vitrectomy; a 23-gauge flexible wire thermoprobe was used to measure intraocular temperatures before, at the end of active vitrectomy, and 5 minutes after closing infusion line. The ocular temperature measurements were taken by contact in middle of vitreous, retina nasal to optic disk, retina just outside of inferior arcade, 2 disc diameter temporal to the fovea and immediately above the fovea.
Results:
Total of 16 patients, 6 males and 10 females, room t° and infusion t° were 68.9°F, Patient t° average was 97.5°F, positive correlation 0.04 was found. The patients' diagnostics were VH, DME, MH, TRD, RRD and ERM. We found that basal retinal temperature was physiologically mild hypothermia and that temperature went down 13 to 14 degrees in average, which was deep hypothermia, described under 86°F; after 5 minutes with infusion line closed it recovered an average of 6.5°F. 1) No statistical differences between patient t, Room t, or infusion t at any time point. 2) Significant differences were observed in t between the 3 time points at all vitrous locations. Pre-vitrectomy t were significantly higher than both intra-operative and post-vitrectomy t. The peri-operative temps were all significantly lower than post-vitrectomy t. The temperature of the vitreous adjacent to the fovea positively correlated with the patients temperature (r = 0.625, P = 0.0096)
Conclusions:
During surgery the vitreous and retina are cooled to deep hypothermia. Rapid re-warming begins once infusion is closed. These t fluctuation are extreme and rapid when compared with therapeutic hypothermia. The retina is physiologically in mild hypothermia. The effects of these t on ocular tissues is unclear and studies that change the infusion t during vitrectomy and long term follow are required.
Keywords: 762 vitreoretinal surgery •
449 cell survival