Abstract
Purpose: :
To measure the effect of body positioning on intraocular pressure (IOP) during robotic prostatectomy.
Methods: :
In this prospective cohort study, IOP was measured using a Tono-pen® XL handheld tonometer in 32 patients undergoing robot-assisted radical prostatectomy. The IOP was measured prior to anesthesia while supine (baseline T1), anesthetized and supine (T2), anesthetized after insufflation of the abdomen with CO2 (T3), anesthetized in deep Trendelenburg (T4), anesthetized in Trendelenburg at the end of the procedure (T5), anesthetized supine prior to awakening (T6), and 1 hour after awakening (T7). ANOVA with repeated measures was used to analyze these data. The mixed procedure in SAS with the autoregressive correlation structure was used to analyze the trend of IOP change over time. Pair wise comparisons of IOP estimates between time points were performed and the Holm’s procedure was used to adjust for multiplicity. In addition, a linear regression model was fit for the time period between T2 and T5.
Results: :
Intraocular pressure was significantly higher in deep Trendelenburg T5 IOP (29.00 +/- 6.00 mmHg) compared to supine T2 (18.26 units higher, SE=0.5596, P-value <0.0001). A time dependent increase in IOP was also noted from T2 to T5 with an increase of 0.18 mmHg per minute. One hour following the conclusion of the procedure, IOP was, on average, significantly higher than baseline (T1) (1.26 units higher, SE=0.5988, P-value=0.0362), despite return to supine position.
Conclusions: :
Significant elevation in intraocular pressure occurs when anesthetized patients are placed in the deep Trendelenburg position following insufflation of the abdomen with CO2. This elevation in intraocular pressure appears to increase with time.
Keywords: intraocular pressure • neuro-ophthalmology: optic nerve