Ocular blood flow in steep Trendelenburg positioning during robotic-assisted radical prostatectomy

Comparison of intraocular pressure during laparoscopic totally extraperitoneal (TEP) versus transabdominal preperitoneal (TAPP) inguinal hernia repair

BACKGROUND

Laparoscopic totally extraperitoneal (TEP) repair and transabdominal preperitoneal (TAPP) repair are standard laparoscopic procedures for inguinal hernia repair. Some evidence has shown that pneumoperitoneum can cause an increase in intraocular pressure (IOP) during surgery. This study aimed to compare intraoperative IOP following extraperitoneal CO₂ insufflation with the TEP approach and intraperitoneal CO₂ insufflation with the TAPP approach.

METHODS

This study is a prospective cohort study. Patients who had inguinal hernias suitable for laparoscopic inguinal hernia repair were assigned to undergo the TEP or TAPP approach. We measured preoperative, intraoperative, and postoperative IOP. The IOP of the TEP and TAPP groups was evaluated using a t test. The relations between peak inspiratory pressure (PIP), mean arterial pressure (MAP), and end-tidal CO₂ (EtCO₂) were estimated using ANOVA. Univariate and multivariate analyses were performed to determine the factors associated with IOP.

RESULTS

There were 50 patients in this study (TEP group n = 25, TAPP group n = 25). The change in intraoperative IOP from the preoperative measurement to the measurement after CO₂ insufflation was not statistically significant in either the TEP or TAPP group (p value = 0.357). There was no significant difference in intraoperative IOP change between the TEP and TAPP groups. Intraoperative MAP and PIP were related to IOP, but intraoperative EtCO2 was not.

CONCLUSIONS

There was no significant intraoperative IOP change during laparoscopic inguinal hernia repair. Both the TEP and TAPP techniques can be performed safely without increasing intraoperative IOP.

Beneficial Effects of Intravenous Magnesium Administration During Robotic Radical Prostatectomy: A Randomized Controlled Trial

INTRODUCTION

Robotic radical prostatectomy requires prolonged pneumoperitoneum and a steep Trendelenburg position. Magnesium can attenuate the stress response and hemodynamic perturbations. This study aimed to evaluate the effects of intravenous magnesium administration on hemodynamics and the stress response in patients undergoing robotic radical prostatectomy.

METHODS

In this prospective, double-blind, randomized controlled study, 52 patients undergoing robotic radical prostatectomy were randomized into two groups: 26 in the magnesium group and 26 in the control group. The patients in the magnesium group received magnesium sulfate 50 mg/kg intravenously, followed by infusion at a rate of 10 mg/kg/h during surgery. The patients in the control group received an equal volume of 0.9% saline. The primary outcomes were the changes in heart rate and mean arterial pressure (MAP) during surgery. The serum stress hormones (adrenocorticotropic hormone, cortisol, epinephrine, and norepinephrine) were also measured.

RESULTS

MAP showed a significant intergroup difference over time (P_group*time = 0.017); it increased significantly at 5 min after Trendelenburg position in the control group and decreased significantly at 30 min after Trendelenburg position in the magnesium group. The intergroup difference in the change in cortisol concentrations was significant over time (P_group*time = 0.006). The cortisol concentration decreased significantly from baseline to 24 h after surgery in the magnesium group but did not change significantly in the control group. The requirement for intraoperative remifentanil was 35% lower in the magnesium group (P = 0.011), and the severity of postoperative pain at 30 min and 6 h after surgery was also lower in the magnesium group (P = 0.024 and P = 0.015).

CONCLUSION

There is a possibility that intravenous magnesium administration during robotic radical prostatectomy reduces the increases in arterial pressure, cortisol concentrations, opioid requirements, and postoperative pain.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02833038.

Change in Intraocular Pressure and Ocular Perfusion Pressure Due to Trendelenburg Positioning

SIGNIFICANCE

This study increases foundational knowledge about the dynamic relationships between intraocular pressure (IOP), blood pressure (BP), and mean ocular perfusion pressure (MOPP) in the setting of steep Trendelenburg positioning and may inform medical decision making for patients in which this positioning is planned.

PURPOSE

The purpose of this study was to explore the demographic and clinical factors related to IOP, MOPP, and BP change during Trendelenburg positioning in a large sample of subjects.

METHODS

A single-cohort interventional study was conducted at the American Academy of Optometry 2017 annual meeting. Baseline demographic data were collected by a secure survey tool. IOP and BP were then measured while seated and again after 1 and 2 minutes in a steep Trendelenburg position. Raw and percentage differences for each variable were compared between time points, and regression analyses demonstrated factors related to change in IOP, BP, and MOPP during steep Trendelenburg positioning.

RESULTS

Median IOP increased from 16.3 mmHg (13.3 to 18.3 mmHg) at baseline to 25.0 mmHg (21.7 to 28.7 mmHg) at 1 minute after assuming the Trendelenburg position. More than 95% of individual eyes exhibited an IOP increase of at least 10%, and 45% had an IOP increase of 10 mmHg or greater. Correspondingly, MOPP fell from 50.3 mmHg (43.4 to 55.4 mmHg) at baseline to 36.3 mmHg (31.9 to 43.3 mmHg). Mean ocular perfusion pressure decreased by at least 10 in 90% of eyes. In multivariate regression analysis, factors independently related to percentage IOP increase were increasing weight, less myopic refractive error, lower baseline pulse, and lower baseline IOP (total r = 0.31, P < .001). Conversely, weight was the only variable independently related to percent MOPP change, and this relationship was weak (r = 0.05, P = .008).

CONCLUSIONS

Our results confirm that steep Trendelenburg positioning causes an increase in IOP and a decrease in MOPP in almost all eyes. Considering the identified causative factors will inform clinical education and provide foundational knowledge for future investigations.

The Effect of Increased Intraocular Pressure During Steep Trendelenburg Positioning in Robotic Prostatectomy and Hysterectomy on Structural and Functional Ocular Parameters

BACKGROUND

Robotic prostatectomy and robotic hysterectomy require steep Trendelenburg positioning. Many authors documented significant increases in intraocular pressure (IOP) during steep Trendelenburg. However, the long-term biological effect of a significant increase in IOP on the structural and functional ocular system is unknown. This study examines the effect of a significant increase in IOP on the visual acuity, retinal nerve fiber layer thickness (RNFLT), and ganglion cell complex (GCC) thickness in 52 patients without preexisting ocular disease of both genders before and 3 months after their procedures.

METHODS

This was a prospective cohort study. The total number of patients included was 56, then 3 females and 1 male case were excluded, totaling 28 robotic hysterectomies and 24 robotic prostatectomies were performed. Patients underwent complete eye examination before the procedure and 3 months after, measuring the main outcome of RNFLT and the secondary outcomes of GCC thickness, foveal threshold (FT), mean deviation (MD), and pattern standard deviation (PSD). These outcomes were analyzed using linear mixed-effects models. On the day of surgery, we examined the IOP after induction of anesthesia, at the end of steep Trendelenburg, and in the recovery room.

RESULTS

There were significant differences in IOP values at the end of steep Trendelenburg versus after induction and 45-60 minutes post-awakening (P < .001 for both groups). No difference between IOP 45 and 60 minutes post-awakening and IOP after induction was observed in either group. The highest IOPs occurred at the end of the steep Trendelenburg time point for both groups. The mean duration of steep Trendelenburg in robotic prostatectomy was 184.6 minutes (standard deviation [SD] = 30.8), while the mean duration in robotic hysterectomy was 123.0 minutes (SD = 29.8). All ophthalmologic examinations were normal preoperatively and 3 months postoperatively. The ocular parameters in the retina and optic disk did not differ significantly before surgery and 3 months after.

CONCLUSIONS

There is a significant increase in IOP during steep Trendelenburg positioning. There was no significant difference in the ocular parameters examined 3 months after the procedure in this cohort.