ABSTRACT
Objective: To evaluate a negative pressure microenvironment designed to contain laser plume during flexible transnasal laryngoscopy. Methods: The Negative Pressure Face Shield (NPFS) was previously reported as well tolerated with initial use on 30 patients. Diagnostic transnasal laryngoscopy was performed on an additional 108 consecutive patients who were evaluated by questionnaires and sequential pulse oximetry. Further study addressed operative transnasal potassium-titanyl-phosphate (KTP) laser laryngoscopy with biopsy done on four patients employing the NPFS. Results: The previously described NPFS version 3 (v.3), a transparent acrylic barrier with two anterior instrumentation ports, was modified by repositioning the side suction port closer to the level of the nose and deepening the lateral sides, squaring off the lower projection. A post-procedure questionnaire employing a 5-point Likert scale ranging from no symptoms (rating of 1) to intolerable (rating of 5) identified excellent patient tolerance of the new design (v.4), among 22 patients evaluated and similar in the comparison to the 116 patients using version 3. Among the 138 patients analyzed, only one patient rated the experience as greater than "mild claustrophobia." 100% of patients answered either "none" or "mild" to the pain and shortness of breath questions. The NPFS (v.4) was then successfully used in four patients for laser laryngoscopy with biopsy of laryngeal papilloma (3/4) and hemorrhagic polyp (1/4). Post-procedure questionnaire identified no shortness of breath (4/4), no claustrophobia (4/4), no pain (4/4) and no significant changes in pulse oximetry during use. Conclusion: Extensive experience in performing diagnostic laryngoscopy with the NPFS directed design changes leading to successful use for transnasal flexible laser laryngoscopy with biopsy in a negative pressure microenvironment. Level of Evidence: Level 2b (Cohort Study).
ABSTRACT
OBJECTIVE: Introduce novel methods and materials to limit microdroplet spread when performing transnasal aerosol generating procedures in the COVID-19 era. METHODS: Prototypes of a negative pressure face shield (NPFS) were tested then used clinically to create a suction-clearing negative pressure microenvironment with controlled access to the nose and mouth. Air pressure measurements within prototypes were followed by prospective evaluation of 30 consecutive patients treated with the device assessed through questionnaires and monitoring oximetry. RESULTS: The NPFS is a transparent acrylic barrier with two anterior instrumentation ports and a side port to which continuous suction is applied. It is positioned on a stand and employs a disposable antimicrobial wrap to secure an enclosure around the head. This assembly was successfully used to complete transnasal laryngoscopy in all 30 patients studied. Tolerance of the design was excellent, with postprocedure questionnaire identifying no shortness of breath (27/30), no claustrophobia (27/30), no pain (29/30), and no significant changes in pulse oximetry. CONCLUSION: Diagnostic laryngoscopy was successfully performed in a negative pressure microenvironment created to limit dispersion of aerosols. Further application of the NPFS device is targeted for use with transnasal laryngeal laser and biopsy procedures to be followed by additional modification to enable intranasal and intraoral procedures in a similar protected environment. LEVEL OF EVIDENCE: Level 2b (Cohort Study).