Simethicone and N-acetyl cysteine in improving mucosal visibility: Towards a “clearer view” during endoscopy

Quality metrics associated with esophagogastroduodenoscopy (EGD) have multiple domains of assessment, including structure, procedure, outcome and adverse events [1]. The procedural domain encompasses procedures in the peri-EGD period with a primary aim of reducing and avoiding missed diagnoses [1, 2]. Improvements in the procedural domain ultimately should lead to improved outcome measures. These indicators are more precisely defined with respect to colonoscopy, including metrics such as bowel preparation, cecal intubation rate, mean withdrawal time and adenoma detection rate; there remains a limitation in the quality metrics in EGD [1, 3]. One such domain in EGD is the quality and adequacy of mucosal visualization [2]. While guidelines agree that adequate mucosal visualization should be achieved with a combination of proper air insufflation, aspiration and the use of mucosal cleansing techniques (MCTs), recommendations for adequate MCTs remain variable [2, 4]. Mucus, bubbles and foam are the key factors that need to be addressed using mucolytics and defoaming agents. While simethicone (SIM) has been used as a defoaming agent, which acts by reducing the surface tension of gas bubbles, N-acetyl cysteine (NAC) and Pronase (commercially available proteolytic enzyme) have been used as mucolytics [1]. These agents have been tried either individually or in combination in at least 10 prior randomized trials and subsequent meta-analyses, with results suggesting an overall improvement in mucosal visualization [4‐6]. In this issue, Nabi and colleagues, in an elegant four-arm randomized trial, provide one of the largest pieces of evidence for the use of pre-medication with SIM alone and with NAC for improving mucosal visibility during EGD [7]. …