A reply

Abstract

We would like to thank Drs Willcox and Turner for their interest in our paper [1]. We are pleased that our publication raised a number of discussion points and we welcome the opportunity to comment. We agree that the risk of transmission of infection from endoscopes is probably low. However, current guidelines suggest that single-use devices should be used where possible (although only if the performance is equivalent) [2, 3]. In addition, the Department of Health bulletin states that endoscopes should be cleaned before and after each use [3]. Consequently, the single-use Ambu aScope is likely to have a shorter ready-to-use time than a re-usable device. This is especially relevant when delay in securing the airway increases the risk to patients, i.e. the Plan B of the Difficult Airway Society guidelines [4]. Furthermore, the single-use fibrescope may be useful in locations remote from the main theatre complex where the fibrescope is infrequently used and an endoscope reprocessing unit may not be readily available. Provision and maintenance of re-usable fibrescopes in such remote locations may be prohibitively expensive. Lastly, the National Creutzfeldt-Jakob Disease Surveillance Unit provides fibrescopes only for established cases of vCJD. The lack of a suction port of the aScope may impair the operator’s ability to clear secretions and blood in the airway. However, the suction channel of the LF-GP Olympus re-usable scope used in our study is only 1.5 mm. Cautious use of external suction, accessing the airway thorough the mouth with either a soft or rigid suction catheter, is likely to provide much better clearance than the limited suction force from the re-usable fibrescope. There are limitations to extrapolating data from any study into clinical practice. Manikin studies have an established place in the evaluation process of an airway device [5, 6]. This is recognised by the Airway Device Evaluation Project Team (ADEPT) [7]. There are number of reasons why no newly introduced device should be used on patients before manikin evaluation is completed. Firstly, the findings of a manikin study can exclude unsafe devices from being used on patients [8, 9] and highlight the design features that require further evaluation on patients [10]. Secondly, they allow for the device to be tested by a large number of clinicians and not only by a small number of researchers and experts. Thirdly, the manikin study design allows for levels of simulation that are likely to be considered unethical if conducted on patients (i.e. crossover study design and simulation of a difficult airway). Although, in our institution, manikin studies go through the same rigorous review as the patient studies (Research and Development and Ethics Committee review), they are still likely to be faster than patient studies in providing initial evidence regarding the safety and usefulness of an untested device. Furthermore, data on historical controls that are required for obtaining level 3b evidence stated in the ADEPT article [7] may not be available for every device currently on the market. Our study was designed to provide evidence on the ease of use and manoeuvrabity of the Ambu aScope when used by a large number of anaesthetists in a manikin set to simulate difficult fiberscope placement. Although this single-use device has a number of potential applications and advantages, the clinical usefulness of the aScope remains to be established.