Effect of weight-adjusted coffeine and propranolol, alone and combined, on simulated surgical skills

Abstract

Purpose : Beta blockers have been studied for their secondary effects on decreasing tremor during surgery, while caffeine may impair surgical performance. This study evaluated novice-level vitreoretinal (VR) surgeons following weight-adjusted doses of caffeine and propranolol, alone and in combination.

Methods : This was a self-controlled single-blinded trial that assessed the surgical performance of VR fellows, with less than 2 years of experience, using the Eyesi simulator. A task sequence was carried out 30 minutes after the masked ingestion of placebo, caffeine, or propranolol pills over 2 days. Five simulations were performed each day. Day 1: testing occurred after the following ordered exposures: placebo; caffeine 2.5 mg/kg (low dose [LD]); caffeine 2.5 mg/kg, totaling 5 mg/kg (high dose [HD]); and propranolol 0.6 mg/kg (HD). Day 2: performance was assessed after the following exposure sequence: placebo; propranolol 0.2 mg/kg (LD); an additional dose of propranolol 0.4 mg/kg, totaling 0.6 mg/kg; and HD caffeine. The outcomes included Eyesi generated score (0-700 [best]), task completion time (min), and the surgical trajectory sum inside the eye (mm). The Mann-Whitney test was used for pairwise comparisons.

Results : Fifteen VR surgeons (9 males, 6 females) were enrolled. Subjects had a significantly higher Eyesi score when treated with LD (617±67 vs 557±109; p=0.05) and HD (608±54.75 vs 557±109; p=0.03) propranolol compared to LD caffeine. The score improvement of propranolol posttreatment after caffeine was lower than with propranolol alone, even at a HD propranolol (570±51.2 vs 608±54.8; p=0.005). The surgical trajectory was shorter after LD propranolol compared to HD caffeine (2080.7±430.4 vs 2566.3±534.9 mm; p=0.02). There was a shorter total time for task completion comparing HD propranolol to placebo (12.3±2.3 vs 13.5±2.8 min; p=0.04). No differences between combined drug intake and placebo were detected in terms of score, time, or trajectory.

Conclusions : Caffeine and propranolol at LD have an impact on the Eyesi score. Propranolol treatment after caffeine is not sufficient to improve the score to the level of propranolol alone. LD propranolol and HD caffeine modify the intraocular trajectory, and HD propranolol alone shortens the time for task completion as compared to placebo. The combined ingestion of both drugs allows a surgeon to return to placebo level performance.

This is a 2020 ARVO Annual Meeting abstract.