Use of Electronic Auscultation in Full Personal Protective Equipment to Detect Ventilation Status in Selective Lung Ventilation: A Randomized Controlled Trial

Abstract

Chest auscultation is the first procedure performed to detect endotracheal tube malpositioning but conventional stethoscopes do not conform to the personal protective equipment (PPE) protocol during the COVID-19 pandemic. This double-blinded randomized controlled trial evaluated the feasibility of using ear-contactless electronic stethoscope to identify endobronchial blocker established selective lung ventilation, simulating endobronchial intubation during thoracic surgery with full PPE. Conventional and electronic auscultation was performed without and with full PPE, respectively, of 50 patients with selective lung ventilation. The rates of correct ventilation status detection were 86 and 88% in the conventional and electronic auscultation groups (p = 1.00). Electronic auscultation revealed a positive predictive value of 87% (95% CI 77 to 93%), and a negative predictive value of 91% (95% CI 58 to 99%), comparable to the results for conventional auscultation. For detection of the true unilateral lung ventilation, the F1 score and the phi were 0.904 and 0.654, respectively for conventional auscultation; were 0.919 and 0.706, respectively for electronic auscultation. Furthermore, the user experience questionnaire revealed that the majority of participant anesthesiologists (90.5%) rated the audio quality of electronic lung sounds as comparable or superior to that of conventional acoustic lung sounds. In conclusion, electronic auscultation assessments of ventilation status as examined during thoracic surgery in full PPE were comparable in accuracy to corresponding conventional auscultation assessments made without PPE. Users reported satisfactory experience with the electronic stethoscope.

Keywords: COVID- 19; auscultation; electronic stethoscop; lung ventilation; personal protective equipment (PPE).

Figure 1

Endobronchial blocker (EB) position and ventilation statuses. (A) The right EB cuff was inflated; this simulates left endobronchial intubation. (B) The left EB cuff was inflated; this simulates right endobronchial intubation. (C) The EB cuff was not inflated; this simulates normal tracheal intubation.

Figure 2

Patient enrolment.

Figure 3

DS101 Electronic Stethoscope. (A). DS101 electronic stethoscope with earpiece microphone. (B). DS101 electronic stethoscope with Bluetooth transmitter for transmission of lung sound to external speaker. (C). DS101 electronic stethoscope connected to external speaker by audio cable.

Figure 4

Illustrations of participant anesthesiologist setting. (A). Illustration of full level C PPE (complying with the requirements of the Occupational Safety and Health Administration) in the electronic stethoscope group. (B). Regular surgical scrubs and cap, not covering the face or ears in the conventional stethoscope group.