Location of the endotracheal tube by pilot balloon-cuff counter-ballottement

Abstract

Study objectives: Mastery of the airway is the primary skill of an emergency physician. A wide variety of techniques and devices have been designed to help obtain and control a patent airway during an emergency airway crisis. Presently, the criterion standard for clinical assessment of proper endotracheal tube verification in the airway is a change in the color indicator on the end-tidal carbon dioxide detector device, augmented by another method such as endotracheal tube aspiration. However, depth of insertion of the endotracheal tube or location within the trachea is usually determined clinically by symmetry of auscultated bilateral breath sounds or subsequently confirmed by postintubation chest radiograph. Earlier work in other clinical settings has demonstrated that with pilot balloon-cuff counter-ballottement (PBCCB) technique, the endotracheal tube cuff can be located externally by gentle palpation at the patient's suprasternal notch, with simultaneous counter-ballottement palpation of the endotracheal tube pilot balloon, using the pilot balloon as a cuff sensor. Palpation and compression of the inflated endotracheal tube cuff distends the pilot balloon accordingly. The purpose of this study is twofold: (1) to obtain a retrospective derivation set of patients, in which the endotracheal tube was repositioned postintubation, representing the rate of endotracheal tube malposition (ie, "usual care"); and (2) to obtain a prospective validation set after a training intervention to determine whether PBCCB provides an additional clinical tool for the emergency physician, thereby reducing the need for endotracheal tube repositioning by postintubation chest radiograph. Methods: In a random, retrospective, convenience sample, we examined 221 radiographs or radiography reports from 419 adult emergency department patients who underwent rapid sequence intubation (RSI) from July 1, 2001, through June 30, 2002. Endotracheal tube position (ie, depth of the endotracheal tube within the trachea above the carina) was quantified. The incidence of postintubation repositioning of the endotracheal tube after chest radiograph comprised the incidence of repositioning or "usual care." Next, emergency physicians received standardized group and individualized training in the application of PBCCB technique. In a subsequent random, prospective, convenience sample during 4 consecutive months, emergency physicians were asked to complete a postintubation procedure card, before the chest radiograph was reviewed, indicating whether the externally palpated endotracheal tube cuff by PBCCB technique was at (preferred), above (acceptable), or below (possibly requiring repositioning) the patient's suprasternal notch. These results were compared with those noted from the postintubation chest radiograph. Results: Of the 221 chest radiographs reviewed in the retrospective derivation set, low malposition (<2 cm above the carina) of the endotracheal tube was noted in 46 (21%), including unrecognized mainstem endobronchial intubation in 14 (30% of the low malpositioned tubes; 6% of the total intubations). In the prospective validation set, 78 postintubation procedure cards were completed for 75 RSI patients by 20 PBCCB-trained emergency physicians. Fifty-two RSI procedures (66%) included the attempted application of the PBCCB technique, whereas it was not attempted in one third (26 patients). For patients who did not undergo PBCCB assessment, 9 patients (35%) required endotracheal tube repositioning, 8 of which were repositioned according to postintubation chest radiograph alone, and 1 of which was repositioned according to asymmetrical breath sounds alone. For the 52 patients undergoing pilot balloon assessment, 16 (31%) endotracheal tubes were repositioned postintubation, 6 by PBCCB technique alone, and 10 by chest radiograph alone; in all 10 of those patients, emergency physicians noted that the endotracheal tube cuff could not be localized by PBCCB, intimating that the endotracheal tube was indeed placed too low in the trachea. Conclusion: Although additional work is warranted, these preliminary observations demonstrate that the use of the PBCCB of the endotracheal tube could add to the emergency physician's airway skills armamentarium to assist in location of the endotracheal tube location within the trachea, avoiding prolonged endobronchial intubation. If validated, the technique could apply to alternative settings in which chest radiograph is not immediately available or in which bedside clinical auscultation skills are compromised by ambient noise or patient transport (eg, emergency medical services or military field medical care).