Biomechanical considerations for optimising subretinal injections.

Subretinal injection is the preferred delivery technique for various novel ocular therapies and is widely used because of its precision and efficient delivery of gene and cell therapies; however, choosing an injection point and defining delivery parameters to target a specified retinal location and area is an inexact science. We provide an overview of the key factors that play important roles during subretinal injections to refine the technique, enhance patient outcomes, and minimise risks. We describe the role of anatomical and physical variables that affect subretinal bleb propagation and shape and their impact on retinal integrity. We highlight the risks associated with subretinal injections and consider strategies to mitigate reflux and retinal trauma. Finally, we explore the emerging field of robotic assistance in improving intraocular manouvrability and precision to facilitate the injection procedure.

Perioperative glycemic measures among non-fasting gynecologic oncology patients receiving carbohydrate loading in an enhanced recovery after surgery (ERAS) protocol.

INTRODUCTION: Preoperative carbohydrate loading is an effective method to control postoperative insulin resistance. However, data are limited concerning the effects of carbohydrate loading on preoperative hyperglycemia and possible impacts on complication rates. METHODS: A prospective cohort study was performed of patients enrolled in an enhanced recovery after surgery pathway at a single institution. All patients underwent laparotomy for known or suspected gynecologic malignancies. Patients who had been diagnosed with diabetes preoperatively and those prescribed total parenteral nutrition by their providers were excluded. Data regarding preoperative carbohydrate loading with a commercial maltodextrin beverage, preoperative glucose testing, postoperative day 1 glucose, insulin administration, and complications (all complications, infectious complications, and hyperglycemia-related complications) were collected. The primary endpoint of the study was the incidence of postoperative infectious complications, defined as superficial or deep wound infection, organ/space infection, urinary tract infection, pneumonia, sepsis, or septic shock. RESULTS: Of 415 patients, 76.9% had a preoperative glucose recorded. The mean age was 60.5±12.4 years (range 18-93). Of those with recorded glucose values, 30 patients (9.4%) had glucose ≥180 mg/dL, none of whom were actually given insulin preoperatively. Median preoperative glucose value was significantly increased after carbohydrate loading (122.0 mg/dL with carbohydrate loading vs 101.0 mg/dL without, U=3143, p=0.001); however, there was no relationship between carbohydrate loading and complications. There was a significantly increased risk of hyperglycemia-related complications with postoperative day 1 morning glucose values ≥140 mg/dL (OR 1.85, 95% CI 1.07 to 3.23; p=0.03). Otherwise, preoperative and postoperative hyperglycemia with glucose thresholds of ≥140 mg/dL or ≥180 mg/dL were not associated with increased risk of other types of complications. DISCUSSION: Carbohydrate loading is associated with increased preoperative glucose values; however, this is not likely to be clinically significant as it does not have an impact on complication rates. Preoperative hyperglycemia is not a risk factor for postoperative complications in a carbohydrate-loaded population when known diabetic patients are excluded. PRECIS: While glucose increased with carbohydrate loading in non-diabetic patients, this was not associated with complications.