The CobraPLA

Abstract

We read with interest the response from Quinn [1] to a paper by Cook and Lowe [2]. We wish to correct the inaccurate references made by him to the two papers by Verghese and Brimacombe [3] and Bapat and Verghese [4], in his response. Both these studies were conducted at the Royal Berkshire Hospital. The first study [3] was a prospective study of 11 910 patients, in which positive pressure ventilation was used in 5241 patients (44%). The incidence of non-fatal aspiration was one in 11 910 (0.0083%). In the second paper [4], there were no aspirations in the 100 patients studied. Indeed, the authors discussed the relevance of a zero numerator and how it should be statistically interpreted. It is not clear how these findings were interpreted by Quinn as a 1% incidence of regurgitation with the laryngeal mask airway. Finally, a more recent study by Bernadini et al. [5] describes a cohort of 15 229 patients in whom the laryngeal mask airway was used, with an incidence of one non-fatal aspiration (0.0065%). In that study, positive pressure ventilation was used in 94% of the patients studied. The first reference cited by Patel and Chatterjee [1] was cited in our reply because it was used by Cook et al. to ‘support the overall safety of the laryngeal mask airway’[2]. We are in full agreement with Patel and Chatterjee that the laryngeal mask airway has had a remarkable record of safe use since its introduction. Indeed, later in our reply we note ‘the excellent track record of the classic laryngeal mask airway’[3]. The second reference [4] was cited because it more specifically studied the kind of patient which Cook et al. reported (Cook's first patient) having suffered aspiration; namely, a female undergoing gynaecological laparoscopy. Patel and Chatterjee are correct in stating that this paper reports a 1% incidence of regurgitation and not aspiration. However, we maintain that most clinicians would equate an occurrence of regurgitation with at least a substantially increased risk for aspiration. Thus the intent of citing these two papers was to reinforce the overall excellent safety record of the laryngeal mask airway while also questioning use of that and other supraglottic airways in patients who might be at increased risk of regurgitation. In any event, we maintain that any supraglottic airway should be able to be used safely in appropriately selected patients who require positive pressure ventilation if properly carried out (by limiting airway pressures to < 20 cm H2O), and the letter by Patel and Chatterjee certainly supports this for the laryngeal mask airway. The thrust of our reply to Cook et al. was to question why this would not be true for the CobraPLA as well. B. QuinnVice President Engineered Medical Systems Inc. (EMS) Indianapolis, IN, USA